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  • Electronic Resource  (1,121)
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  • 1990-1994  (1,121)
  • Physical Chemistry  (1,121)
  • 101
    Electronic Resource
    Electronic Resource
    Mechanism of the hydride transfer reaction of leuco crystal violet with cyanomethylene acceptors (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 218-220 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the hydride transfer of Leuco Crystal Violet to form the Crystal Violet, cation, the role of cyanomethylene acceptors was found to be essentially different from that of p-benzoquinones, both previously believed to act as π-acceptors in the same manner.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070408
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  • 102
    Electronic Resource
    Electronic Resource
    Calibration of a semi-empirical procedure for predicting the ground-state spin multiplicities of open-shell molecules. Applications to new systems (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 207-217 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A semi-empirical configuration interaction (CI) algorithm is presented for predicting the ground-state spin multiplicity of open-shell systems. The computed energy gaps ΔE(LS—HS) of model systems, Y-phenyl-X-phenyl-Y, where Y is a nitrene or nitroxide radical and X is an exchange coupling unit, are critically compared with the available experimental data. The current method has attenuated the deficiencies of the earlier algorithm proposed by Lahti and Ichimura and the predictions are qualitatively clearer, facilitating the classification of high- and low-spin topologies for isomeric species. The relative effectiveness of different exchange couplers can be discerned semi-quantitatively, and several new exchange couplers are described. The reasons for the qualitative failure of the earlier algorithm are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070407
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  • 103
    Electronic Resource
    Electronic Resource
    N-alkylation and N-arylation of anilines starting from a mild N—Mg reagent: Its activation causing the ‘N=C’ coupling to extend the unified structure-reactivity relationshipAryliminodimagnesium reagents, part XXIV. For part XXIII, see ref. 3b. (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 9-17 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: New N-alkylation and N-arylation procedures starting from anilinomagnesium (ArNHMgBr) are reported. For N-alkylation with alkyl bromides, addition of hexamethylphosphoramide to an ArNHMgBr solution in tetrahydrofuran (THF) is effective. After heating at 55°C, N-monoalkylation product was obtained in 60-90% yield, slight dialkylation taking place. The combined use of aryliminodimagnesium [ArN(MgBr)2] with α,ω-dibromoalkanes led to N-arylazacycloalkanes. For N-arylation with iodobenzene, replacement of THF with pyridine and additional use of copper(I) iodide are effective. After heating at 115°C with iodobenzene, mono- and diarylation products were obtained, the former being predominant. The combined use of ArNHMgBr and N,N,N′,N′-tetramethylethylenediamine as the ligand of copper species is effective for elimination of diarylation and other undesired products, and leads to diarylamines in excellent yield. The method is of advantage over the conventional Ullmann and Chapman methods. The polar solvents and copper salt are effective additives for inducing ‘inert combinations’ of ArNHMgBr or ArN(MgBr)2 with alkyl and aryl halides into N—C coupling, to extend the unified view proposed for the reactivity of magnesium reagents. The difference in the roles of N—Mg and N—Cu species is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070103
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  • 104
    Electronic Resource
    Electronic Resource
    Water-Catalysed hydrolysis of p-nitrobenzyl cellulose xanthate (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 287-295 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The spontaneous hydrolysis of p-nitrobenzyl cellulose xanthate (CelXNB) with a degree of substitution (DS) in the range 2-9 was studied in 10% aqueous ethanol at pH 10, and was followed spectrophotometrically by the appearance of p-nitro-α-toluenethiol, in a continuous-flow system where the reactor was shaken. CelXNB was characterized by solid-state 13C NMR spectra. The reaction occurs through two parallel processes due to two xanthate ester groups with different reactivities. The fast hydrolysis was ascribed to the reaction of the C-2 + C-3 isomers, whereas the slow hydrolysis was due to the C-6 isomer. The percentage of the latter is much higher than C-2 + C-3. The solvent isotope effect of the fast hydrolysis (k′H2O/)k′H2D 11 was 2·22 ± 0·16 and the proton inventory indicated that there is only one proton transfer involved in the transition state, where a second water (or a neighbouring OH group) acts as a general base. The entropy of activation of the fast hydrolysis was only 3·3 ± 0·8 e.u., suggesting that the water molecules involved are highly oriented with respect to the coordinates required to reach the transition state. It is proposed that they form part of the three-dimensional hydrogen-bonded ice-like structure that involves the cellulose matrix.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070604
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  • 105
    Electronic Resource
    Electronic Resource
    Spectrometry and reactivity of phenalenyl anions (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 296-302 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The aromatic odd-alternant phenalenyl anion and a number of its derivatives were prepared in order to study the perturbation of this conjugated anion by methyl and methoxy groups. The conjugated anions were studied by means of 1H and 13C NMR spectrometry, alkylation experiments and semi-empirical calculations. It was found that a substituent at a charged carbon atom perturbs the entire conjugated system, whereas substituents at inactive (uncharged) carbon atoms have a large effect on the positions ortho to the substituent.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070605
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  • 106
    Electronic Resource
    Electronic Resource
    Potentiometric evaluation of the ion-selective characteristics of 1,4-bridged cubyl diester crown ethers (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 303-308 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cubane diester crown ethers were tested as ion-selective electrodes in poly(vinyl chloride) (PVC) membranes. The four ionophores studied proved to be good K+ neutral carriers, showing Nernstian and near-Nernstian responses to this ion, in the range 10-4-10-1 M. The fixed interferences method was used to determine relative selectivity coefficients for all the electrodes. The highest selectivity for potassium relative to sodium, lithium, calcium and magnesium ions using potassium tetrakis(p-chlorophenyl)borate (KTpClPB) as a resistance modifier and NPOE as a plasticizer was obtained with the 1,4-cubyl diester-25-crown-7 ether ionophore. The effects of KTpCIPB on membrane selectivity were assessed; its removal was found to increase the selectivity of the four ionophores for potassium relative to cesium, sodium, calcium and magnesium ions with minimal effects on lithium and ammonium ions. The compounds tested exhibited a fast Nernstian response to changes in K+ concentration which was stable to within 〈100 μV h-1.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070606
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  • 107
    Electronic Resource
    Electronic Resource
    Hydride transfer reactions of Michler's hydride with different π-accetors (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 309-315 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The hydride transfer reactions of 4,4′-bis(dimethylaminophenyl)methane (Michler's hydride) with p-benzoquinones were studied. The rate of formation of Michler's Hydrol Blue was followed spectrophotometrically. The second-order rate constants and the activation parameters were estimated. The formation of a charge-transfer complex was observed at low temperatures. Stable and unstable paramagnetic species formed during the reactions were assigned by ESR spectroscopy. The observed kinetic behaviour and the stoichiometry were in line with those previously obtained for the systems involving Leuco Crystal Violet, Leuco Malachite Green and Leuco Bindschedler's Green. Hence the reaction is considered to proceed according to the so-far accepted multi-step mechanism. However, when tetracyano-p-quinodimethane or tetracyanoethylene was used as a π-acceptor, a comparatively stable radical ion pair was formed as a result of a one-electron transfer, followed by the gradual formation of Michler's Hydrol Blue. The kinetic behaviour and the stoichiometry of the reaction were examined, together with the enhanced kinetic effects of added triethylamine. A modified mechanism for these systems is proposed. The role of cyanomethylenes was found to be essentially different from that of p-benzoquinones, and therefore π-acceptors are divided into two groups of cyanomethylenes and p-benzoquinones.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070607
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  • 108
    Electronic Resource
    Electronic Resource
    Vinyl ether hydrolysis. 30. Effect of β-carboxy and β-carbomethoxy substitution (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 316-322 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rates of hydrolysis of the vinyl ether functional groups of (Z)- and (E)-β-methoxyacrylic acid and (Z)-and (E)-β-methoxymethacrylic acid and their methyl esters were measured in aqueous perchloric acid solution. Additional rate measurements were also made for one substrate, (Z)-β-methoxymethacrylic acid, in buffer solutions down to pH 7, and a rate profile was constructed. The results show that the β-carboxy and β-carbomethoxy substituents produce strong rate retardations, ranging from 2000- to 25 000-fold, for both Z- and E-isomers in both the acrylic and methacrylic acid series. The rate profile for (Z)-β-methoxymethacrylic acid indicates that ionization of this substrate to the carboxylate ion form rises the rate of hydrolysis by a factor of 240. It is argued that this difference in reactivity of ionized and non-ionized forms of the substrate is due to conjugative and inductive effects of the substituents, rather than β-lactone formation as suggested in an earlier observation of the same phenomenon in a different system.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070608
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  • 109
    Electronic Resource
    Electronic Resource
    Equilibrium acidities and homolytic bond dissociation enthalpies of the acidic C—H bonds in dialkyl malonates and related compounds (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 751-756 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The equilibrium acidities, pKHA, of 18 dialkyl malonates, five alkyl 2-cyanoacetates and nine malononitriles and the oxidation potentials of their conjugate anions, EOX(A-), were measured in dimethyl sulfoxide solution. The homolytic bond dissociation enthalpies (BDEs) of their acidic C-H were estimated by combining their pKHA and EOX(A-) values. The pKHA values of the dialkyl malonates were found to increase from 15·9 to 16·4 to 18·4 as the dialkyl groups were changed from dimethyl to diethyl to di-tert-butyl, but the BDEs of the acidic C-H bonds remained constant [95·3±0·3 kcal mol-1] (1 kcal = 4·184 kJ). Introduction of methyl, ethyl, isopropyl and tert-butyl groups into the 2-position of diethyl malonate caused the equilibrium acidities to increase by 2·0, 2·4, 3·8 and 8·0 pKHA units, respectively, and the BDE values to decrease by 4·4, 3·7, 2·5 and 0·8 kcal mol-1, respectively. Introduction of a phenyl group into the 2-position of diethyl malonate had no effect on the acidity, but weakened the acidic C-H bond by 10 kcal mol-1. The effects on acidity and BDE of introducing 3,4,5- (MeO)3C6H2CO, CF3, Me3N+, c-C5H10N, p-MeC6H4, p-NO2C6H4, PhO, F and c-C5H5N+ groups into the 2-position of diethyl malonate were also examined.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610071214
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  • 110
    Electronic Resource
    Electronic Resource
    Study of the hydrogen bond donor acidity of binary aqueous mixtures and their role in reversed-phase liquid chromatography (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 757-769 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The solvatochromic hydrogen bond donor (HBD) acidity parameter (αmix) of aqueous mixtures of methanol, acetonitrile, propan-2-ol and tetrahydrofuran were determined spectrophotometrically. The study was carried out at 25deg;C as a function of composition. The indicators used were 2,6-diphenyl-4-(2,4,6-triphenyl-N-pyridino)phenolate, 2,6-dichloro-4-(2,4,6-triphenyl-N-pyridino)phenolate and Fe(LL)2(CN)2 (LL = N-(2-pyridylbenzylidene)-3,4-dimethylaniline). The HBD acidity of the aqueous organic mixtures was related to retention in reversed-phase liquid chromatography.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610071215
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  • 111
    Electronic Resource
    Electronic Resource
    Micellar catalysis of organic reactions. Part 35. Kinetic determination of the critical micelle concentration of cationic micelles in the presence of additives (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 437-441 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The critical micelle concentration of solutions of cetyltrimethylammonium bromide and of tetradecyltrimethylammonium bromides were determined by a kinetic method. This involved the determination of the rates of the hydroxydehalogenation of some activated aromatic substrates over a wide range of detergent concentrations. Measurements were made in solutions containing significant quantities of added hydroxyl ion and substrates which were themselves amphiphilic. Conventional methods cannot be applied with confidence to such systems. The effects of changing hydroxyl ion concentrations, added sodium bromide, changing the nature of the aromatic substrate (whether neutral or charged), the identity of the micellar counterion and the temperature were investigated. It was wound that added bromide or hydroxyl ions resulted in a lower CMC whereas increased temperature led to an increase in the CMC. The nature of the micellar counterion (Br, F, OH, SO4) had little effect on the CMC. The presence of a charged aromatic substrate led to a considerable lowering of the CMC, whereas the neutral aromatic substrate used showed very little effect.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070808
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  • 112
    Electronic Resource
    Electronic Resource
    Bimolecular nucleophilic substitution at a resonance-stabilized carbenium ion: Elevated value of cross-interaction constant, imbalanced transition state and the non-interactive phenomenon (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 448-454 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A characteristic feature in the bimolecular nucleophilic substitution reactions at a resonance-stabilized carbenium ion has been shown to be an imbalanced transition state resulting in an elevated value of the cross-interaction constant, which in turn leads to a non-interactive phenomenon. Examples of the reactions of ring-substituted phenylethyl and benzhydryl cations are given.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070810
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  • 113
    Electronic Resource
    Electronic Resource
    Micellar catalysis of organic reactions. Part 36. Nucleophilic aromatic substitution reactions in hydroxy functionalized micelles with bulky head groups (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 442-447 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reaction of several nitro activated aromatic halides with hydroxide ions was studied in the presence of hydroxy functionalized micelles containing bulky head groups, e.g. C16H33N+R2CH2CH2OH Br-, where R = Me, Et, Bu. In a biphasic reaction, the aryl halide is first converted into an aryl mincellar ether which subsequently reacts with hydroxide ions to form the phenolic product. Despite the increased nucleophilicity of hydroxide ions as water is squeezed away from the micelle surface by the bulky head groups, no direct reaction of the aromatic substrate with hydroxide ion is detectable. In the second phase of reaction, the breakdown of the aryl micellar ether to form the phenolic product, the order of reactivity in the different micelles is dependent on the steric interactions between substituents ortho to the reaction centre and the head group of the micelle. For compounds having one substituent ortho to the reaction centre, the order of reactivity is Bu 〉 Me 〉 Et, whereas for 2-chloro-1,3-dinitrobenzene, which has two substituents ortho to the reaction centre, the order is Me 〉 Et 〉 Bu.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070809
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  • 114
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610070901
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  • 115
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610071101
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  • 116
    Electronic Resource
    Electronic Resource
    Gas phase thermolysis of N-(tert-butylthio)allylamine and N-(tert-butylthio)diethylamine (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 585-590 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The title sulphenamides were pyrolysed in a stirred-flow reactor at temperatures of 310-410°C, pressures of 8-15 Torr and residence times of 0·4-2 s using toluene as the carrier gas. N-(tert-Butylthio)allylamine formed 73 ± 4% isobutene, 23 ± 3% propene and N-allylthiohydroxylamine. The first-order rate coefficients for the formation of isobutene and propene, respectively, followed the Arrhenius equations kC4(s-1) = 1012·52 ± 0·36 exp(-163 ± 5 kJ mol-1 RT) and kC3(s-1) = 1010·99 ± 0·29 exp(-151 ± 4 kJ mol-1 RT) N-(tert-Butylthio)diethylamine gave 97 ± 1% isobutene, 1·9 ± 0·4% isobutane and N,N-diethylthiohydroxylamine. The first-order rate coefficients for isobutene elimination followed the Arrhenius equation k(s-1) = 1013·45 ± 0·24 exp(-164 ± 3 kJ mol-1 RT). The formation of the products is interpreted in terms of an elimination reaction with a unimolecular, four-centered, cyclic transition state. The reactivity of these sulphenamides was found to be much higher than that of previously studied alkyl or aryl tert-butyl sulphides and disulphides.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610071102
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  • 117
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    Directional hydrogen bonding in the MM3 force field. I (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 591-609 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The MM3 molecular mechanics program calculates a fair representation of hydrogen bonding interactions, but to improve the MM3 hydrogen bond potential, a directional term has been added to the hydrogen bonding function. The resulting total function was reoptimized. Comparisons of the hydrogen bonding potential functions from ab initio, the original MM3, the current MM3(92) force field and the reoptimized MM3 force field MM3(94) for a variety of C,N,O systems are described.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610071103
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  • 118
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    Reactions of 1,3-dihaloadamantanes with diphenylphosphide ions by the SRN1 mechanism. Competition between intermolecular and intramolecular electron transfer reactions (1994)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 610-614 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reactivity of 1,3-dihaloadamantanes with diphenylphosphide ions (Ph2P-) in liquid ammonia was studied. 1,3-Dichloroadamantane (1a), 1-bromo-3-chloroadamantane (1b) and 1,3-dibromoadamantane (1c) reacted with Ph2P- ions under photostimulation by the SRN1 mechanism. Irradiation of 1c without Ph2P- ions gave no reaction (〈5%). Three products were found: 1,3-bis(diphenyphosphinyl)adamantane (2), (3-X-1-adamantyl)diphenylphosphine (X = Cl, 3a; X = Br, 3b) and 1-adamantyldiphenylphosphine (4). Compounds 2 and 4 were formed by intramolecular electron transfer (ET) of the radical anion 3a-· (3b-·); whereas 3a (3b) were formed by intermolecular ET of this radical anion to the substrates. It was observed that the product distribution depends on the substrate and reaction conditions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610071104
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  • 119
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    Kinetics and mechanisms of the reactions of OH with some oxygenated compounds of importance in tropospheric chemistry (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 113-130 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the reactions have been studied in a discharge flow system under pseudo-first-order conditions. The OH concentration was monitored by laser induced fluorescence and helium was used as the carrier gas. Values of k1 = (8.1 ± 1.7) × 10-13, k2 = (1.31 ± 0.26) × 10-11, k3 = (2.6 ± 0.5) × 10-11, and k4 = (2.5 ± 0.4) × 10-11 cm3 molecule-1 s-1, at 298 K and 1 torr total pressure, were obtained.To validate the newly constructed system the rate constant for the reaction was determined in a similar manner. The value of k5 = (6.7 ± 0.9) × 10-12 cm3 molecule-1 s-1 at 298 K and 1 torr total pressure is in very good agreement with other literature values.The mechanisms for the atmospheric degradation of these compounds have been constructed to allow their incorporation in a photochemical trajectory computer model, to assess their impact on photochemical ozone creation in the troposphere. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/kin.550260112
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  • 120
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    Two-color multiphoton decomposition of 1-bromo 2-fluoroethaneWe are pleased to make this contribution in memory of Bob Back. Bob collaborated with our group at Chalk River on many projects over the last decade. He was a friend, colleague, and teacher to us and we have felt his absence on many occasions, not the least of which was while writing this article. We often asked one another, “How would Bob have explained the results?” Needless to say, Bob will continue to be missed. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 147-158 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiphoton decomposition of 1-bromo 2-fluoroethane (CH2BrCH2F, BFE) with a two-color CO2 infrared laser is reported as a function of number of laser pulses. For single color irradiation at a wavelength chosen to excite BFE, the decomposition product, vinyl fluoride, which accumulates during the many-pulse MPD experiment, is found to deactivate BFE decomposition. When a second laser, tuned to a vinyl fluoride absorption is introduced, coincident with the first, the vinyl fluoride is found to activate further BFE decomposition. These results are accounted for in terms of a pressure-dependent model. Changes in model parameters, upon addition of the second laser, are shown to be consistent with interpretations in terms of collision-dependent reaction schemes. © 1994 John Wiley & Sons, Inc.
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    Improved method for fitting falloff data (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 273-281 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An extension of the dimensionless treatment of Troe is developed for fitting falloff data from unimolecular and recombination reactions. This method using dimensionless parametrizations derived from accurate numerical solutions of the master equation for system with any type of activated complex and energy transfer probability distribution, is as easily implemented as Troe's method, and allows global fitting of an entire set of pressure- and temperature-dependent rate coefficients. © 1994 John Wiley & Sons, Inc.
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    URL: http://dx.doi.org/10.1002/kin.550260205
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    Study of the pseudo-steady-state kinetics of CO2 hydrate formation and stability (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 289-297 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article describes a dynamic model for formation and stability of CO2-hydrate on the interface of liquid CO2(LCO2) and ocean water at large depths. Experimental results indicate that a thin film of hydrate naturally forms on the interfaces between LCO2 and water, and inhibits diffusion between the two phases. Experiments further shows that the flux of CO2 through the hydrate film is dependent of the CO2-concentration in the ambient sea water. The model proposed here explains these phenomena by introducing four major mechanisms; diffusion of water to the LCO2-phase, formation of hydrate in the LCO2-hydrate interface, decay of hydrate in the water-hydrate interface, and diffusion of CO2 through the water phase. The model explains the CO2 flux not by diffusion through the hydrate film, but suggest a mechanism of continuous hydrate formation and decay. The overall effect is a “moving,” pseudo-steady-state hydrate film due to transport of CO2 through the film. The film velocity is dependent of liquid-liquid diffusivity parameters and reaction constant, and lacking experimental values of these parameters, an order-of-magnitude analysis is done by fitting the model to experimentally obtained data for the overall film velocity. The motivation for this work is to elucidate options for CO2 depositions in deep oceans, of which liquid CO2 sequestration is believed to be one of the most feasible. Spreading of CO2 from a liquid CO2-lake and associated lowering of pH in the ecosystem surrounding the lake is of large concern. The work presented here concludes that diffusion of CO2 in the ocean is largely reduced by the hydrate film and suggests that hydrate formation may alleviate some of the environmental concerns regarding deep ocean sequestration of liquid CO2. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/kin.550260207
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    The CSP method for simplifying kinetics (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 461-486 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Computational Singular Perturbation (CSP) method of simplified kinetics modeling is presented with emphasis on its comparative merits versus conventional methodologies. A new “refinement” procedure for the basis vectors spanning the fast reaction subspace is presented. A simple example is first worked through using the conventional partial-equilibrium and quasi-steady approximations, and is then treated in some detail using CSP. © 1994 John Wiley & Sons, Inc.
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    URL: http://dx.doi.org/10.1002/kin.550260408
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    Kinetic study of the oxidation of ethanol by 3,4-lutidine chromium(VI) peroxide in dichloromethane solution (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 497-502 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation kinetics of ethanol with 3,4-lutindine chromium(VI) peroxide (LCP) were investigated by monitoring the absorbance change at 565 nm in dichloromethane solution. The reaction had a first-order dependence on oxidant and a fractional (one half) dependence on reactant. The stoichiometric ratio between LCP and ethanol was 1 : 2. The activation parameters were determined from temperature dependence of the reaction rate. It was found that the cleavage of the peroxide groups of LCP is primarily responsible for the oxidant of ethanol to acetaldehyde. Based on the kinetic results obtained (including deuterium isotope effect) a plausible mechanism is proposed. © 1994 John Wiley & Sons, Inc.
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    URL: http://dx.doi.org/10.1002/kin.550260502
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  • 125
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    Kinetics and mechanisms of the gas-phase reactions of the NO3 radical with aromatic compounds (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 511-525 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and nitrated products of the gas-phase reactions of the NO3 radical with methoxybenzene, 1,2-, 1,3-, and 1,4-dimethoxybenzene, dibenzofuran and dibenzo-p-dioxin have been investigated at 297 ± 2 K and in the presence of one atmosphere of air. A relative rate method was used for the kinetic measurements. No reactions of methoxybenzene or dibenzofuran with the NO3 radical were observed. The dimethoxybenzenes were observed to react by H-atom abstraction and NO3 radical addition to the aromatic ring, while dibenzo-p-dioxin reacted by NO3 radical addition to the aromatic rings. For these compounds, the NO3 radical addition pathways were observed to be reversible. At the NO2 concentrations employed, the NO3-aromatic adducts reacted with NO2 and the observed rate constants increased with increasing NO2 concentration. However, for dibenzo-p-dioxin the observed rate constant became independent of the NO2 concentration for concentrations ≥ 4.8 × 1013 molecule cm-3, and under these conditions the rate constant of 6.8 × 10-14 cm3 molecule-1 s-1 was taken to be that for addition of the NO3 radical to the aromatic rings. The proposed NO3 radical reaction mechanisms are discussed. © 1994 John Wiley & Sons, Inc.
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  • 126
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    Yield of 16OS18O from the 18OH initiated oxidation of CS2 in 16O2 (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 551-560 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The yield of 16OS18O from the 18OH initiated oxidation of CS2 in 16O2 was measured by using a discharge flow reactor coupled to a chemical ionization mass spectrometer. 16OS18O is the dominant SO2 isotopomer produced with a yield of 0.90 ± 0.20 relative to 18OH loss. The errors are estimates for the uncertainty at the 95% confidence level. The implications of these results to the understanding of the CS2 oxidation mechanism are discussed. © 1994 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
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    Erratum (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 593-594 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260513
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260601
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260701
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  • 130
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    The IR multiphoton decomposition of CF3I. The effect of inert and reactive gases (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 705-718 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The multiphoton decomposition of CF3I with a pulsed CO2 laser has been studied at incident fluences of 0.6 and 1.2 J/cm2. The effect of pressure on the reaction probability for dissociation of CF3I was measured in the presence of added isobutane, Ar and CO2. In the experiments with isobutane, the CF3 radicals generated by the decomposition of excited CF3I react to yield CF3H in competition with the recombination to C2F6. The laser absorption cross section was also measured as a function of fluence at a pressure of 0.1 torr of CF3I and with 0.5-2.0 torr of added isobutane. The experimental results were modeled with a master equation in order to obtain information on the energy transferred by collisions of excited CF3I with the bath molecules. An energy dependent value of 〈ΔE〉d produces the best fit to the experimental data. Integration of the rate equations to account for the fractional product yield, [CF3I]/[C2F6], allowed for the calculation of the specific rate constant for hydrogen abstraction from isobutane by CF3 radicals. The value obtained is dependent on the total pressure and higher than expected at room temperature. From these results, an effective temperature for the reaction mixture was calculated. © 1994 John Wiley & Sons, Inc.
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    A novel correlative relationship among rates of complexation of 1:1 copper(II) diketonates and basicity of the ligand (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 743-747 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An exceptional kinetic behavior on the reactivity of β-diketones against copper(II) have been found. Some relationship between ligand basicity and unexpected enhancement on the rates of complex formation, which may be useful for predicting rate constants of similar monochelated copper(II) complexes, are established. © 1994 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/kin.550260708
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260801
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  • 133
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    Pulsed laser powered homogeneous pyrolysis: A computational analysis (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 779-799 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of the pulsed laser powered homogeneous pyrolysis technique for measuring unimolecular decomposition rate constants under unambiguously homogeneous conditions is investigated by numerical simulation of the experiment. The coupled partial differential equations which govern the gas dynamics and chemical kinetics are solved numerically and the results analyzed. Conditions under which rate constants can be extracted from the experimental data using a simplified analysis are determined. The effects of five sources of error in the simplified analysis are computed. A correlation is presented which may be used to correct for overestimation of the rate constant which is inherent in the simple analysis. Conditions under which the other four sources of error become negligible are presented. Overall, it is expected that this technique will be capable of routinely measuring rate constants within a factor of 2, and will do much better when a high power laser with a uniform beam profile is used and/or a well characterized thermal monitor molecule is available which decomposes with kinetic parameters close to that of the reactant being investigated. © 1994 John Wiley & Sons, Inc.
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    Thermal Decomposition of CF3C(O)O2NO2, CClF2C(O)O2NO2, CCl2FC(O)O2NO2, and CCl3C(O)O2NO2 (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 827-845 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Haloacetyl, peroxynitrates are intermediates in the atmospheric degradation of a number of haloethanes. In this work, thermal decomposition rate constants of CF3C(O)O2NO2, CClF2C(O)O2NO2, CCl2FC(O)O2NO2, and CCl3C(O)O2NO2 have been determined in a temperature controlled 420 l reaction chamber. Peroxynitrates (RO2NO2) were prepared in situ by photolysis of RH/Cl2/O2/NO2/N2 mixtures (R = CF3CO, CClF2CO, CCl2FCO, and CCl3CO). Thermal decomposition was initiated by addition of NO, and relative RO2NO2 concentrations were measured as a function of time by long-path IR absorption using an FTIR spectrometer. First-order decomposition rate constants were determined at atmospheric pressure (M = N2) as a function of temperature and, in the case of CF3C(O)O2NO2 and CCl3C(O)O2NO2, also as a function of total pressure. Extrapolation of the measured rate constants to the temperatures and pressures of the upper troposphere yields thermal lifetimes of several thousands of years for all of these peroxynitrates. Thus, the chloro(fluoro)acetyl peroxynitrates may play a role as temporary reservoirs of Cl, their lifetimes in the upper troposphere being limited by their (unknown) photolysis rates. Results on the thermal decomposition of CClF2CH2O2NO2 and CCl2FCH2O2NO2 are also reported, showing that the atmospheric lifetimes of these peroxynitrates are very short in the lower troposphere and increase to a maximum of several days close to the tropopause. The ratio of the rate constants for the reactions of CF3C(O)O2 radicals with NO2 and NO was determined to be 0.64 ± 0.13 (2σ) at 315 K and a total pressure of 1000 mbar (M = N2). © 1994 John Wiley & Sons, Inc.
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260901
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  • 136
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    Kinetics and mechanism of the reaction of CH3O with NO (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 887-901 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the reaction of CH3O with NO and the branching ratio for HCHO product formation, obtained as ΓHCHO = (Rate of HCHO formation) / (Rate of CH3O decay), have been studied using a discharge flow reactor. Laser induced fluorescence has been used to monitor the decay of the CH3O radical and the build-up of the HCHO product. Overall rate constants and product branching ratios were measured at room temperature over the pressure range of 0.72-8.5 torr He. Three reaction mechanisms were considered which differed in the routes of HCHO formation: (i) direct disproportionation; (ii) via an energized collision complex; or (iii) both reaction routes. It has been shown that data on the pressure dependence of the overall rate constant are not sufficient to distinguish between these mechanisms. In addition, an accurate value of ΓHCHO∞ is required. Analysis of the available experimental data provided 0.0 and about 0.1 as the lower and upper limit for ΓHCHO∞, respectively. Since the rate constants derived for CH3ONO formation were not sensitive to the value assumed for ΓHCHO∞, kCH3ONO° = (1.69 ± 0.69) × 10-29 cm6 molecule-2 s-1 and kCH3ONO∞ = (2.45 ± 0.31) × 10-11 cm3 molecule-1 s-1 could be derived. The rate constant obtained for formaldehyde formation when extrapolated to zero pressure is kHCHO0 = (3.15 ± 0.92) × 10-12 cm3 molecule-1 s-1. © 1994 John Wiley & Sons, Inc.
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    The role of water in promoting the oxidative dehydrogenation of ethane (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 921-928 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition of water vapor has a strong positive effect on the rate of ethane oxidation at 575°C. This effect is attributed to the role of H2O as a third body in the decomposition of H2O2 to OH radicals. Carbon tetrafluoride likewise enhances the rate of ethane conversion, although not to the extent realized with H2O. A kinetic model, based on known elementary reactions, adequately accounts for the conversions and selectivities observed as a function of H2O pressure, temperature, contact time, and O2 pressure. © 1994 John Wiley & Sons, Inc.
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550261001
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  • 139
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    Micellar effects upon the reaction of hydroxide ion with 2-phenoxyquinoxaline (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 963-972 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic micelles of alkyltrimethylammonium chloride and bromide (alkyl = n—C12H25, n—C14H29, and n—C16H33) catalyze and anionic micelles of sodium dodecyl sulfate inhibit the reaction of hydroxide ion with 2-phenoxyquinoxaline (1). Inert anions such as chloride, nitrate, mesylate, and n-butanosulfonate inhibit the reaction in CTABr by competing with OH- at the micellar surface. The overall micellar effects on rate in cationic micelles and dilute electrolyte can be treated quantitatively in terms of the pseudo-phase ion-exchange model. The determined second-order rate constants in the micellar pseudo-phase are smaller than the second-order constants in water. © 1994 John Wiley & Sons, Inc.
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  • 140
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    Kinetics and thermochemistry of the reaction of acetylene and nitric oxide (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 997-1011 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The shock tube data of Ogura [5] on the pyrolysis of C2H2/NO mixtures (1100-1500 K) is shown to be consistent with a simple mechanism whereby radicals are both initiated and terminated by NO (Scheme I). The scheme accounts for the rate of formation of the main product, vinylacetylene (VA), the lesser products CO and HCN and a very minor product, propionitrile. It is also shown to be consistent with other studies below 900 K and observation at 300 K on the reactions of vinyl radicals with NO. The substantial inhibition of vinyl acetylene formation by 5% NO makes untenable any substantial role of vinylidene in the C2H2 pyrolysis above 1000°K.The reaction of NO with acetylene is an efficient source of HCN. It appears to be a general reaction of NO with substituted acetylenes and below 900 K a mechanism is presented to account for the production of acrylonitrile (AN) from the reaction of NO with VA.Thermochemical data are estimated on ΔfH°298 and S°298 for some alkyl-NO, vinyl NO, and acetylene NO compounds and radicals and some new and some revised group values are estimated for estimating ΔfH°298 of derivatives of hydroxyl amines, imines, and isoxazolines. © 1994 John Wiley & Sons, Inc.
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  • 141
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    Catalytic activity of Manganese(II)-Gluconate complex in reactions of Hydrogen Peroxide (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 1121-1134 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetic studies of the hydrogen peroxide decomposition catalyzed by the dimeric Mn(II)-gluconate complex, in alkaline medium, showed evidence for the oxidative cleavage of the ligand, leading to the formation of formaldehyde as one of the products. In the presence of a large excess of other hydroxylated substrates, such as methanol or ethylene glycol, a significant increase in the yield of formaldehyde was observed, corroborating the observed peroxidase activity in this system, in addition to the catalase activity. Oxygen free radicals were detected as intermediates of reaction, by ESR spectroscopy using the spintrapping method, only under aerobic conditions. Therefore, a nonradical mechanism was proposed for the reaction, based on the formation of a peroxo-Mn(II) complex, and its further reduction to the previous Mn(II) species. © 1994 John Wiley & Sons, Inc.
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    The study of decomposition reactions through the exchange of thermal energy (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 1151-1166 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In many decomposition reactions, the reaction velocity can be described as a product of two functions: a temperature dependent part K(T) and the kinetic function f(1 - α), where T designates the temperature and α the fraction of reactant that has decomposed. The physical interpretation of these functions is discussed for both solid and homogeneous systems. A method is described by which f(1 - α) and K(T) can be determined from kinetic data. The mechanism of decomposition can subsequently be identified which should be consistent with the derived kinetic parameters. The method has been applied to analyze the kinetics of the thermal decomposition of nitromethane. © 1994 John Wiley & Sons, Inc.
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    URL: http://dx.doi.org/10.1002/kin.550261203
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    Rate constants for the gas-phase reactions of Ozone with unsaturated Aliphatic Alcohols (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 1185-1191 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas-phase reaction of ozone with unsaturated alcohols in air has been investigated at atmospheric pressure and ambient temperature (288-291 K). Cyclohexane was added to scavenge the hydroxyl radical which forms as a product of the ozone-unsaturated alcohol reaction. The reaction rate constants, in units of 10-18 cm3 molecule-1 s-1, are 16.2 ± 0.7 for (±) 3-buten-2-ol, 17.9 ± 1.8 for 1-penten-3-ol, 10.0 ± 0.3 for 2-methyl-3-buten-2-ol, 169 ± 25 for cis-2 penten-1-ol, and 251 ± 41 for 2-buten-1-ol (mixture of isomers). Substituent effects on reactivity are discussed. The reactivity of unsaturated alcohols towards ozone is similar to that of their alkene structural homologues. Implications of these results with respect to the atmospheric persistence of unsaturated alcohols are briefly discussed. © 1994 John Wiley & Sons, Inc.
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    Kinetic and mechanistic aspects of the NO oxidation by O2 in aqueous phase (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 1207-1227 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation kinetics of NO by O2 in aqueous solution was observed using a stopped flow apparatus. The kinetics follows a third order rate law of the form k · [NO]2 · [O2] in analogy to gas-phase results. The rate constant at 296 K was measured as (6.4 ± 0.8) · 106 M-2 s-1 with an activation energy of 2.3 kcal/mol and a preexponential factor of (4.0 ± 0.5) · 108 M-2 s-1. The rate constant displays a very slight pH dependence corresponding to less than a factor of three over the range 0 to 12. The system NO/O2 in aqueous solution is an efficient nitrosating agent which has been tested using phenol as a substrate over the pH range 0 to 12. The rate limiting step leading to formation of 4-nitrosophenol is the formation of the reactive intermediate whose competitive hydrolysis yields HONO or NO2-. The absence of NO3- in the autoxidation of NO, the exclusive presence of NO2- as a product of the nitrosation reaction of phenol, and the kinetic results of the N3- trapping experiments point towards N2O3 as the reactive intermediate. © 1994 John Wiley & Sons, Inc.
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    Selected recent publications of R.A. Back (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 5-6 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/kin.550260103
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  • 146
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    The lifetimes of gas phase CO2·- and N2O·- calculated from the transition probability of the autodetachment process A- → A + e- (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 7-24 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure to calculate the quantum mechanical transition probability of a unimolecular primary chemical process, A- → A + e- is investigated for the circumstance where A- and A have different numbers of vibrational and rotational degrees of freedom (one is linear, the other not). A procedure is introduced to deal with the coupling between the vibrational and rotational motions. The proposed method was applied to calculating the lifetimes of CO2·- and N2O·- in the gas phase. The geometry optimizations and frequency calculations for CO2, CO2·-, N2O, and N2O·- are performed at HF, MP2, and QCISD(T) levels with 6-31G* or 6-31+G* basis sets, in order to obtain reliable geometric and spectroscopic information on these systems. Lifetimes are calculated for several of the lower vibrational-rotational states of the anions, as well as for the Boltzmann distribution of states at 298 K. The lifetime of the lowest vibrational-rotational state of CO2·-, is 1.03 × 10-4 s, and of the lowest vibrational state with rotational levels weighted by Boltzmann distribution at 298 K, 1.50 × 10-4 s. These values are in good agreement with the experimental number, 9.0 ± 2.0 × 10-5 s, and support the experimental evidence that CO2·- was formed in its ground vibrational level by the techniques used. The lifetime of CO2·- calculated with Boltzmann distribution over its vibrational and rotational levels at 298 K, is 1.51 × 10-5 s. There are no direct measurements of the lifetime of N2O·-, but it was estimated to be greater than 10-4 s from experimental evidence. The predicted lifetimes of N2O·-, at its lowest vibrational-rotational state (0 K) and lowest vibrational state with rotational levels weighted by the Boltzmann distribution at 298 K, are 238 and 19.1 s, respectively. The lifetime of N2O·- at thermal equilibrium at 298 K is 6.66 × 10-2 s, indicating that electron loss from the excited vibrational states of N2O·- is significant. This study represents the first theoretical investigation of CO2·- and N2O·- lifetimes. © 1994 John Wiley & Sons, Inc.
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    Gas-phase kinetic study of the silylene addition reaction to acetylene and acetylene-d2 over the temperature range 291-613 KThis article is dedicated to the memory of Bob Back. We remember him as a painstaking experimentalist and a deep thinker about all aspects of kinetics and photochemistry, as a modest man, and a true friend. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 45-60 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Time-resolved studies of silylene, SiH2, generated by laser-flash photolysis of phenylsilane, have been employed to obtain rate constants for its bimolecular reactions with C2H2 and C2D2. The reactions have been studied in the gas-phase, in the pressure range 1-100 torr (with SF6 bath gas) at five temperatures in the range 291-613 K.Reaction with C2H2 is pressure dependent, consistent with a third body assisted association reaction. However the lack of a simple fit to RRKM calculated values suggests a more complex process with another reaction channel. Reaction with C2D2 is faster than with C2H2, showing a pressure dependent isotope effect. The data are consistent with a rapid isotopic scrambling mechanism. Further RRKM modeling of a three-channel decomposition mechanism for the suggested silirene adduct (intermediate) provides a semi-quantitative fit to the data. Rate constants extracted from the modeling are shown to be consistent with a mechanism leading to formation of both ethynylsilane and vinylsilylene, as previously proposed by O'Neal, Ring et al. from higher temperature studies. An enthalpy surface is shown to be consistent with this mechanism. © 1994 John Wiley & Sons, Inc.
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    Reactions of the copper dimer, Cu2, in the gas phaseThis article is submitted in the memory of Bob Back. He is much missed as a valued friend and colleague at NRC. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 85-96 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Cu2 with several small molecules have been studied in the gas phase, under thermalized conditions at room temperature, in a fast-flow reactor. They fall into one of two categories. Cu2 does not react with O2, N2O, N2, H2, and CH4 at pressures up to 6 torr. This implies bimolecular rate constants of less than 5 × 10-15 cm3 s-1 at 6 torr He. Cu2 reacts with CO, NH3, C2H4, and C3H6 in a manner characteristic of association reactions. Second-order rate constants for all four of these reagents are dependent on total pressure. The reactions with CO, NH3, and C2H4 are in their low pressure limit at up to 6 torr He buffer gas pressure. The reaction with C3H6 begins to show fall-off behavior at pressures above 3 torr. Limiting low-pressure, third-order rate constants are 0.66 ± 0.10, 8.8 ± 1.2, 9.3 ± 1.4, and 85 ± 15 × 10-30 cm6 s-1 in He for CO, NH3, C2H4, and C3H6, respectively. Modeling studies of these rate constants imply that the association complexes are bound by at least 20 kcal mol-1 in the case of C2H4 and C3H6 and at least 25 kcal mol-1 in the other cases. The implications of these results for Cu-ligand bonding are developed in comparison with existing work on the interactions of these ligands with Cu atoms, larger clusters, and surfaces. © 1994 John Wiley & Sons, Inc.
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  • 149
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    Etching of GaAs (100) with gaseous H/CH3 mixturesThis article is contributed to the special edition in honor of Dr. Robert A. Back. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 131-140 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: GaAs (100) wafers were etched in mixtures of hydrogen atoms and methyl radicals. The atoms were formed in a remote hydrogen plasma, and a fraction of these were converted into methyl radicals by introducing methane into the flow system upstream from the semiconductor surface. The flux of hydrogen atoms into the reaction chamber was determined by isothermal calorimetry. The methyl radical flux passing over the substrate was then calculated using previously determined rate parameters for the reaction between atomic hydrogen and methane, and a simple modeling program. The GaAs etch rates were about an order of magnitude faster when methyl radicals were present in the hydrogen atom stream, and were found to follow a first-order dependence on the partial pressure of methyl radicals. Absolute rate constants were determined and an Arrhenius activation energy of 1.2 kcal mol-1 was calculated. The values of k and Ea are consistent with a diffusion-controlled process. SEM photographs of the surface revealed small crystallographic features that made the surface appear very rough. XPS analysis indicated that these surfaces were arsenic deficient. A mechanism is proposed for the etching of GaAs by a combination of methyl radicals and hydrogen atoms. © 1994 John Wiley & Sons, Inc.
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    The rate of methyl radical decomposition at high temperatures and pressuresDedicated to the memory of R.A. Back. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 159-169 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rate constants are calculated for CH3 (+ Ar) ⇄ CH2 + H (+ Ar) at the limiting low-pressure, the limiting high-pressure, as well as the intermediate fall-off ranges. The results show that published experimental rate constants for methyl dissociation correspond to the fall-off region close to the low-pressure limit. At the low-pressure limit the activation energy is less than the bond dissociation energy, in agreement with experimental results. Forward and backward rate coefficients at the high-pressure limit are compared with other theoretical calculations. More theoretical and experimental work is necessary to understand the reverse reaction and its competing reactions, as well as the decomposition channel leading to CH + H2. © 1994 John Wiley & Sons, Inc.
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260201
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  • 152
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    Thermal decomposition of di-t-butyl peroxide in the presence of (CH3)2C=CH2: Reactions of CH3, (CH3)2ĊCH2CH3, and (CH3)2ĊCH2C(CH3)2CH2CH3 radicals (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 227-246 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A study of the reaction initiated by the thermal decomposition of di-t-butyl peroxide (DTBP) in the presence of (CH3)2C=CH2 (B) at 391-444 K has yielded kinetic data on a number of reactions involving CH3 (M·), (CH3)2CCH2CH3 (MB·) and (CH3)2ĊCH2C(CH3)2CH2CH3 (MBB·) radicals.The cross-combination ratio for M· and MB· radicals, rate constants for the addition to B of M· and MB· radicals relative to those for their recombination reactions, and rate constants for the decomposition of DTBP, have been determined. The values are, respectively, \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {\phi \left({{\rm M} \cdot {\rm, MB} \cdot} \right) = \left({2.3 \pm 0.2} \right)} \\ {\log \left({{{k_2} \mathord{\left/ {\vphantom {{k_2} {k_5^{1/2}}}} \right. \kern-\nulldelimiterspace} {k_5^{1/2}}}} \right) = \left({3.18 \pm 0.32} \right) - {{\left({28.0 \pm 1.3} \right)} \mathord{\left/ {\vphantom {{\left({28.0 \pm 1.3} \right)} \theta}} \right. \kern-\nulldelimiterspace} \theta}} \\ {\log \left({{{k_9} \mathord{\left/ {\vphantom {{k_9} {k_{15}^{1/2}}}} \right. \kern-\nulldelimiterspace} {k_{15}^{1/2}}}} \right) = \left({2.2 \pm 0.9} \right) - {{\left({24.4 \pm 2.5} \right)} \mathord{\left/ {\vphantom {{\left({24.4 \pm 2.5} \right)} \theta}} \right. \kern-\nulldelimiterspace} \theta}} \\ {\log \left({k_0} \right) = \left({15.57 \pm 0.23} \right) - {{\left({156.3 \pm 2.2} \right)} \mathord{\left/ {\vphantom {{\left({156.3 \pm 2.2} \right)} \theta}} \right. \kern-\nulldelimiterspace} \theta}} \\\end{array} $$\end{document} where θ = RT ln 10 and the units are dm3/2 mol-1/2 s-1/2 for k2/k51/2 and k9/k151/2, s-1 for k0, and kJ mol-1 for E.Various disproportionation-combination ratios involving M·, MB·, and MBB· radicals have been evaluated. The values obtained are: Δ1(M·, MB·) = 0.79 ± 0.35, Δ1(MB·, MB·) = 3.0 ± 1.0, Δ1(MBB·, MB·) = 0.7 ± 0.4, Δ1(M·, MBB·) = 4.1 ± 1.0, Δ1(MB·, MBB·) = 6.2 ± 1.4, and Δ1(MBB·, MBB·) = 3.9 ± 2.3, where Δ1 refers to H-abstraction from the CH3 group adjacent to the center of the second radical, yielding a 1-olefin. © 1994 John Wiley & Sons, Inc.
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    In memory of Robert Arthur back (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 1-3 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 154
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    The flash photolysis of aqueous solutions of rhodizonic and croconic acids (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 25-36 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The flash photolysis of aqueous solutions of rhodizonic and croconic acids has been studied in the presence and absence of electron acceptors. No transient absorption which could be identified with an excited state was observed with either anion. The rate of recovery of the ground state in the absence of additives was a first-order process with both acids and gave rate constants for deactivation of the excited state, kD, of 2.4 × 105 s-1 for rhodizonate and 2.8 × 105 s-1 for croconate. With croconate dianion in the presence of three acceptors, 4-nitrobenzylbromide, methylviologen, and biacetyl, a transient absorption was detected, with a maximum absorbance at 500 nm, and was tentatively identified with the monoanion radical, formed following electron transfer to the acceptor. From the rate of growth of the transient, rate constants for the rate of electron transfer to the acceptor were measured as follows: 4-nitrobenzylbromide: 2.8 × 109 M-1 s-1; methyl viologen: 3.7 × 1010 M-1 s-1; and biacetyl: 2.0 × 108 M-1 s-1. The significance of the measurements is discussed in relation to the mechanism proposed for the photochemical reactions of these dianions. © 1994 John Wiley & Sons, Inc.
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    The nitrogen pentoxide dissociation equilibriumWith warm memories of Bob Back - for although no new rate constants are reported, I think he would have smiled on this attempt to sort things out. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 61-71 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The third-law method is used to assess the authenticity of available equilibrium constants for the thermal dissociation of N2O5 ⇌ NO2 + NO3. © 1994 John Wiley & Sons, Inc.
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    Isotope effect in Ni + C2H4 (C2D4) association reactionThis article is dedicated to the memory of R.A. Back. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 97-111 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The association reactions of atomic nickel with ethene and fully deuterated ethene in carbon dioxide buffer gas at 295 K have been investigated in the pressure range 5-100 torr, using a laser photolysis-laser fluorescence technique. By comparison with results of ab initio quantum chemistry calculations for the complex Ni[C2H4], the data are shown to be consistent with reaction on both ground and excited state potential energy surfaces. A simple rate equations treatment is described which shows the form of the pressure dependence of the second-order recombination rate coefficient in this case. Under conditions which are expected to hold for the Ni + C2H4 (C2D4) reaction, the pressure dependence has the standard Lindemann-Hinshelwood form, with the limiting high pressure rate constant given by an apparent value which reflects the degree to which the participating electronic states are coupled by nonadiabatic transitions. The limiting high pressure behavior of the recombination rate coefficient for Ni + C2H4 is not strongly affected by deuterium isotope substitution. However, the effect on the low pressure rate constant is large and consistent with RRKM unimolecular reaction theory. This validates the use of RRKM calculations for estimating the binding energy of the complex from kinetic data. The binding energy of Ni[C2H4] is estimated to be 35.2 ± 4.2 kcal mol-1. © 1994 John Wiley & Sons, Inc.
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    Role of resin-manganese(II) complexes in hydrogen peroxide decomposition (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 341-346 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of hydrogen peroxide decomposition has been investigated in the presence of Wofatit KPS (4% DVB, 40-80 μm) resin in the form of mono (mea), di (dea), triethanolamine (tea), ethylenediamine (eda), and N,N′-diethylethylenediamine (deeda)- Mn(II) complexes. The rate constant k (per g dry resin) was evaluated over the temperature range 25-40°C. The reaction was first-order with respect to [H2O2]. The rate constant, k, with the three ethanolamines decreased in the following order mea 〉 dea 〉 tea which is the same order of basicity. Also, k value with deeda is lower than eda as a result of steric hindrance. The peroxo metal complex which formed at the beginning of the reaction, was found to contain the catalytic active species. The rate of reaction was proportional to [Mn-complex], [H2O2] and [H+]-1. The activation parameters were calculated and a probable reaction mechanism is proposed. © 1994 John Wiley & Sons, Inc.
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260401
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  • 159
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    Rates of reaction between the nitrate radical and some aliphatic ethers (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 367-380 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rate coefficients for the reaction of NO3 with dimethyl ether, diethyl ether, di-n-propyl ether, and methyl t-butyl ether (MTBE) have been determined. Absolute rates were measured at temperatures between 258 and 373 K using the fast flow-discharge technique. Relative rate experiments were also made at 295 K in a reactor equipped with White optics and using FTIR spectroscopy to follow the reactions. The measured rate coefficients (in units of 10-15 cm3 molecule-1 s-1) at 295 K are: 0.26 ± 0.11, 2.80 ± 0.23, 6.49 ± 0.65, and 0.64 ± 0.06 for dimethyl ether, diethyl ether, di-n-propyl ether, and methyl t-butyl ether, respectively. The corresponding activation energies are 21.0 ± 5.0, 17.2 ± 4.0, 15.5 ± 2.1, and 20.1 ± 1.7 kJ mole-1. The error limits correspond to the 95%-confidence interval. © 1994 John Wiley & Sons, Inc.
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    A shock tube study of the OH + OH → H2O + O reaction (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 389-401 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate coefficient for the reaction has been determined in mixtures of nitric acid (HNO3) and argon in incident shock wave experiments. Quantitative OH time-histories were obtained by cw narrow-linewidth uv laser absorption of the R1(5) line of the A2 σ+ ← X2 Πi (0,0) transition at 32606.56 cm-1 (vacuum). The experiments were conducted over the temperature range 1050-2380 K and the pressure range 0.18-0.60 atm. The second-order rate coefficient was determined to be \documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 = 9.40 \times 10^{- 5} T^{4.77} \exp \left({{{+ 4570} \mathord{\left/ {\vphantom {{+ 4570} {T\left[{\rm K} \right]}}} \right. \kern-\nulldelimiterspace} {T\left[{\rm K} \right]}}} \right)\left[{{\rm cm}^{\rm 3} {\rm mol}^{- 1} {\rm s}^{- 1}} \right] $$\end{document} with overall uncertainties of +11%, -16% at high temperatures and +25%, -22% at low temperatures. By incorporating data from previous investigations in the temperature range 298-578 K, the following expression is determined for the temperature range 298-2380 K \documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 = 3.57 \times 10^4 T^{2.40} \exp \left({{{+ 1063} \mathord{\left/ {\vphantom {{+ 1063} {T\left[{\rm K} \right]}}} \right. \kern-\nulldelimiterspace} {T\left[{\rm K} \right]}}} \right)\left[{{\rm cm}^{\rm 3} {\rm mol}^{- 1} {\rm s}^{- 1}} \right]. $$\end{document} © 1994 John Wiley & Sons, Inc.
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    Rate constant of the α-pinene + atomic hydrogen reaction at 295 K (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 527-534 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate constant of the reaction of α-pinene with atomic hydrogen was determined at 295 K using the fast-flow reactor technique directly coupled to a mass spectrometric detection technique. The value was found to be equal to (9.8 ± 3.3) × 10-13 cm3 molecules-1 s-1 and independent of the helium pressure between 1 and 2 torr. The major reaction product formed is pinane showing that the stabilization of the adduct radical C10H17*, followed by a subsequent hydrogen atom addition step, is the important reaction route. © 1994 John Wiley & Sons, Inc.
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  • 162
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    Error analysis for complex kinetics systems methyl-vinyl cross-radical reactions (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 535-544 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Many rate constants, particularly for radical-radical reactions, are determined in systems exhibiting complex kinetics. Parameters often comprise several species concentrations, absorption cross sections, and rate constants. They cannot be obtained from an exact analytic expression, and therefore, must be solved iteratively through an efficient numerical differential equation solver. We examine here the reaction kinetics of the CH3 and the C2H3 mixed-radical system, generated by excimer laser photolysis of methyl vinyl ketone (MVK) at 193.3 nm. As a model, a detailed error analysis for determination of the cross-radical reaction rate constant, the initial CH3 and C2H3 radical concentrations are performed using a least-squares modeling program (Acufit). The least-squares program, an assumed mechanism, a detailed set of signal-averaged data, are viewed as the measuring “instrument.” The output of the “instrument” consists of a “signal” that is fit to the data using the least-squares criterion. This gives estimated parameters that are examined with respect to random as well as systematic errors. The biases due to uncertainties of each known parameter and combined uncertainties on the measured parameters are assessed. © 1994 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
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  • 163
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    Concerted mechanism of the aminolysis of 2,4,6-trinitrophenyl o-ethyl dithiocarbonate in aqueous ethanol (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 571-575 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of the title substrate with a series of secondary alicyclic amines are subjected to a kinetic study in 44 wt% aqueous ethanol, 25.0°C, and ionic strength 0.2 M (KCl). The Brönsted-type plot (log kN vs. pKa of the amine, where kN is the second-order rate coefficient) obtained is linear with slope β = 0.53, which indicates a concerted mechanism. The predicted Brönsted break for a hypothetical stepwise mechanism is pKa0 = 8.7, which was not observed (pKa range of amines: 6-11). The same reaction in water is stepwise, which shows that the tetrahedral intermediate found in water is much destabilized by the change of solvent from water to aqueous ethanol. © 1994 John Wiley & Sons, Inc.
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  • 164
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    Kinetics and mechanism of oxidation of glycine, alanine, and threonine by fluoride coordinated bismuth(V) in aqueous HClO4-HF medium (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 577-585 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of oxidation of amino acids viz. glycine, alanine, and threonine with bismuth(V) in HClO4-HF medium have been studied. The kinetics of the oxidation of all these amino acids exhibit similar rate laws. The second-order rate constants were calculated to be 2.04 × 10-2 dm3 mol-1 and 2.72 × 10-2 dm3 mol-1 s-1 for glycine and alanine, respectively, at 35°C and 5.9 × 10-2 dm3 mol-1 s-1 for threonine at 25°C. All the possible reactive species of both bismuth(V) and amino acids have been discussed and a most probable kinetic model in each reaction has been envisaged. © 1994 John Wiley & Sons, Inc.
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  • 165
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    Spectrokinetic study of SF5 and SF5O2 radicals and the reaction of SF5O2 with NO (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 615-629 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: UV spectra of SF5 and SF5O2 radicals in the gas phase at 295 K have been quantified using a pulse radiolysis UV absorption technique. The absorption spectrum of SF5 was quantified from 220 to 240 nm. The absorption cross section at 220 nm was (5.5 ± 1.7) × 10-19 cm2. When SF5 was produced in the presence of O2 an equilibrium between SF5, O2, and SF5O2 was established. The rate constant for the reaction of SF5 radicals with O2 was (8 ± 2) × 10-13 cm3 molecule-1 s-1. The decomposition rate constant for SF5O2 was (1.0 ± 0.5) × 105 s-1, giving an equilibrium constant of Keq = [SF5O2]/[SF5][O2] = (8.0 ± 4.5) × 10-18 cm3 molecule-1. The SF5—O2 bond strength is (13.7 ± 2.0) kcal mol-1. The SF5O2 spectrum was broad with no fine structure and similar to the UV spectra of alkyl peroxy radicals. The absorption cross section at 230 nm was found to (3.7 ± 0.9) × 10-18 cm2. The rate constant of the reaction of SF5O2 with NO was measured to (1.1 ± 0.3) × 10-11 cm3 molecule-1 s-1 by monitoring the kinetics of NO2 formation at 400 nm. The rate constant for the reaction of F atoms with SF4 was measured by two relative methods to be (1.3 ± 0.3) × 10-11 cm3 molecule-1 s-1. © 1994 John Wiley & Sons, Inc.
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  • 166
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    Base hydrolysis of (αβ S)-(o-methoxy benzoato) (tetraethylenepentamine) cobalt(III) ion: A comparative study of the role of ion pairs and micelles (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 681-692 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of base hydrolysis of (αβ S)-(o-methoxy benzoato) (tetraethylenepentamine)cobalt(III) obeyed the rate law: kobs = kOH[OH-], in the range 0.05 ≤ [OH-]T, mol dm-3 ≤ 1.0, I = 1.0 mol dm-3, and 20.0-40.0°C. At 25°C, kOH = 13.4 ± 0.4 dm3 mol-1 s-1, ΔH≠ = 93 ± 2 kJ mol-1 and ΔS≠ = 90 ± 5 JK-1 mol-1. Several anions of varying charge and basicity, CH3CO2-, SO32-, SO42-, CO32-, C2O42-, CH2(CO2)22-, PO43-, and citrate3- had no effect on the rate while phthalate2-, NTA3-, EDTA4-, and DTPA5- accelerated the process via formation of the reactive ion pairs. The anionic (SDS), cationic (CTAB), and neutral (Triton X-100) micelles, however, retarded the reaction, the effect being in the order SDS〉 CTAB 〉 Triton X-100. The importance of electrostatic and hydrophobic effects of the micelles on the selective partitioning of the reactants between the micellar and bulk aqueous pseudo-phases which control the rate are discussed. © 1994 John Wiley & Sons, Inc.
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  • 167
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    Methyl isocyanide is an RRKM molecule after all (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 729-736 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Classical trajectory calculations on the methyl isocyanide molecule at energies above 25,000 cm-1 confirm that the rate of reaction to methyl cyanide is bimodal, with a very fast rate before 0.1 ps, and a slower rate from then on. We conclude that before 0.1 ps, the reacting molecules are unrandomized, but thereafter, they are essentially randomized, with decay to products being, to a good approximation, pure exponential. We estimate that the time for randomization is roughly 0.3 ps at energies near the reaction threshold of 13,500 cm-1. © 1994 John Wiley & Sons, Inc.
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  • 168
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    Kinetics of the thermal decomposition of ferrocenyl azide: Character of ferrocenyl nitrene (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 631-641 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Arrhenius parameters for the thermal decomposition of ferrocenyl azide in isooctane are A = (5.1 ± 1.4) × 1012 s-1 and Eact = 113.1 ± 0.9 (kJ mol-1) and the rate is relatively insensitive to solvent (isooctane, benzene, acetonitrile: 1:1.7:2.4). The results indicate a relatively nonpolar transition state which is considerably “tighter” than for a normal bond fission reaction. The Arrhenius parameters are comparable to those for aromatic azides and do not offer any support for anchimeric assistance by the iron atom. A kinetic scheme is presented which accounts for the observed products: Nitrogen, ferrocene, aminoferrocene, azoferrocene, and insoluble material. Rates of hydrogen abstraction by the intermediate ferrocenyl nitrene from cyclohexane, benzene, and acetonitrile are used to show that the nitrene is nucleophilic. © 1994 John Wiley & Sons, Inc.
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  • 169
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    Reactions of cobalt(III) complexes with free radicals derived from thymine (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 693-703 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature of interaction of Co(III) complexes such as Co(III)EDTA and Co(III)NTA with transient adducts of thymine such as TOH·, T·-, and TH· formed in the gamma radiolysis of thymine were studied. The study shows that TOH radicals do not undergo electron transfer reaction with Co(III) complexes whence no radiosensitization of thymine by Co(III) complexes was observed. Electron transfer however, takes place from T·- and TH· to Co(III) complexes. A plausible mechanism of radiolysis of thymine in presence of Co(III) complexes is discussed. © 1994 John Wiley & Sons, Inc.
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  • 170
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    Kinetics of the reactions of Cl atoms with CH3Br and CH2Br2 (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 719-728 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate coefficients for the reactions of Cl atoms with CH3Br, (k1) and CH2Br2, (k2) were measured as functions of temperature by generating Cl atoms via 308 nm laser photolysis of Cl2 and measuring their temporal profiles via resonance fluorescence detection. The measured rate coefficients were: k1 = (1.55 ± 0.18) × 10-11 exp{(-1070 ± 50)/T} and k2 = (6.37 ± 0.55) × 10-12 exp{(-810 ± 50)/T} cm3 molecule-1 s-1. The possible interference of the reaction of CH2Br product with Cl2 in the measurement of k1 was assessed from the temporal profiles of Cl at high concentrations of Cl2 at 298 K. The rate coefficient at 298 K for the CH2Br + Cl2 reaction was derived to be (5.36 ± 0.56) × 10-13 cm3 molecule-1 s-1. Based on the values of k1 and k2, it is deduced that global atmospheric lifetimes for CH3Br and CH2Br2 are unlikely to be affected by loss via reaction with Cl atoms. In the marine boundary layer, the loss via reaction (1) may be significant if the Cl concentrations are high. If found to be true, the contribution from oceans to the overall CH3Br budget may be less than what is currently assumed. © 1994 John Wiley & Sons, Inc.
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  • 171
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    Dissolution kinetics of copper(II) oxide in water saturated by sulphur dioxide (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 737-742 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dissolution and the kinetics of dissolution of cooper(II) oxide in water saturated by sulphur dioxide has been studied. In the experiments, the particle size, the flow rate of the gas, the solid to liquid ratio, and the reaction temperature have been chosen as parameters, while the stirring rate was held constant. As a result of present experiments, it was observed that the decrease of the particle size, the solid to liquid ratio, and an increase of the reaction temperature increased the dissolution rate. It was also observed that the flow rate of sulphur dioxide in the range of its flow rate values did not affect the dissolution rate.The reaction kinetics of copper(II) oxide according to the heterogeneous reaction models was examined and it was found that the dissolution rate was controlled by chemical reaction. The calculated activation energy is 66.50 kJmol-1. © 1994 John Wiley & Sons, Inc.
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  • 172
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    High-temperature ignition of propane with MTBE as an additive: Shock tube experiments and modeling (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 757-770 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ignition of propane has been studied in a shock tube and by computational modeling to determine the effect of methyl tert-butyl ether (MTBE) as a fuel additive. MTBE and isobutene were added in amounts up to 25% of the fuel to propane-oxygen-argon mixtures in shock tube experiments covering a range of temperatures between 1450 and 1800 K. Ignition delays were measured from chemiluminescence at 432 nm due to excited CH radicals. The temperature dependence of the ignition rates was analyzed to yield Arrhenius parameters of Ea ca. 40 kcal/mol and A ca. 109 s-1 for the overall propane reaction and Ea ca. 34 kcal/mol and A ca. 108.3 s-1 for the overall propane/MTBE reaction. Reactions involving MTBE and its decomposition products were combined with an established propane mechanism in a numerical model to describe the kinetic interaction of this additive with a typical hydrocarbon fuel. The experiments and the kinetic model both show that MTBE and isobutene retard propane ignition with nearly equal efficiency. The kinetic model demonstrates that isobutene kinetics are responsible for inhibition by both MTBE and isobutene, and the specific elementary reactions that produce this behavior are identified. © 1994 John Wiley & Sons, Inc.
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  • 173
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    Kinetics of the reaction of C6H5 with HBr and DBr (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 771-778 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate constants for the reaction of C6H5 with HBr and DBr have been measured with the cavity-ring-down method in the temperature range of 297 to 523 K and 297 to 500 K, respectively. These rate constants can be effectively represented, in units of cm3/s, by \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{l} k_{{\rm HBr}} = 10^{- 10.40 \pm 0.24} \exp \left[{{{\left({- 554 \pm 208} \right)} \mathord{\left/ {\vphantom {{\left({- 554 \pm 208} \right)} T}} \right. \kern-\nulldelimiterspace} T}} \right]{\rm and} \\ k_{{\rm DBr}} = 10^{- 10.36 \pm 0.17} \exp \left[{{{\left({- 662 \pm 151} \right)} \mathord{\left/ {\vphantom {{\left({- 662 \pm 151} \right)} T}} \right. \kern-\nulldelimiterspace} T}} \right]{\rm.} \\ \end{array} $$\end{document} Both activation energies are similar and positive, contrary to those of alkyl radical reactions, all of which exhibit negative temperature dependencies. The difference, as pointed out before [1], could be accounted for by the electron-withdrawing effect of the phenyl vis-à-vis the electron-donating ability of the alkyls. © 1994 John Wiley & Sons, Inc.
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  • 174
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    Rates of processes initiated by pulsed laser production of F atoms in the presence of HCl, CH4, and CF3H (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 813-825 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Time-resolved vibrational chemiluminescence from HF has been recorded following the production of F atoms by the pulsed laser photolysis (λ = 266 nm) of F2 in the presence of HCl, CH4, and CF3H. In the first two cases, experiments have been conducted by observing emission from HF(ν = 3) at four temperatures from 295 to 139 K. Rate constants have been determined over this range of temperature for the reactions of F atoms with HCl and CH4 and of CH3 radicals with F2, and for the relaxation of HF(ν = 3) by HCl and CH4. The reaction of F atoms with CF3H is slower than those with HCl and CH4 and measurements on the emission from HF(ν = 2) have been used to infer rate constants for reaction and relaxation only at 295 K. © 1994 John Wiley & Sons, Inc.
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  • 175
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    CO2 laser excitation of triethylsilane: Time resolved luminescence of diethylsilyl radical (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 857-867 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The infrared multiphoton excitation of triethylsilane in the gas phase, with a pulsed CO2 laser at high intensities (I 〉 700 MW/cm2), produced an intense luminescence. The spectrum and time profile of this luminescence was studied as a function of pressure, and laser frequency. The radiative lifetime of this emission was 357 ± 10 ns, and the quenching rates by Cl2 and NO were determined from lifetime measurements. A reasonable mechanism for the interpretation of this luminescence involves the initial infrared multiphoton decomposition of triethylsilane, followed by the secondary infrared multiphoton excitation of the primary photofragment diethylsilyl radical, which subsequently undergoes relaxation to an excited electronic state. The addition of O2 resulted in a new chemiluminescence at shorter wavelengths, which corresponds to the SiO* chromophore group. © 1994 John Wiley & Sons, Inc.
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  • 176
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    Branching ratio of the C2H2 + O reaction at 290 K from kinetic modelling of relative methylene concentration versus time profiles in C2H2/O/H systems (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 869-886 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In earlier work on the room temperature oxidation of C2H2 by O atoms, two distinct sources of methylene radicals have been identified: (i) direct, primary production via channel 1b of the C2H2 + O reaction, and (ii) delayed formation via the secondary reaction 3 involving the products HCCO and H of the other primary channel 1a: Presently, it was confirmed by a detailed sensitivity analysis that the precise shapes of the resulting total methylene concentration-versus-time profiles in C2H2/O systems depend strongly on the k1a/k1b branching ratio. Along that line, the important parameter k1a/k1b was determined from relative CH2 concentration-versus-time profiles measured in a variety of C2H2/O/H systems using Discharge Flow-Molecular Beam sampling Mass Spectrometry techniques (DF-MBMS). The data analysis was carried out by deductive kinetic modelling; the method, as applied to profile shapes, is discussed at length. Via this novel, independent approach, the CH2(3B1) yield of the two-channel C2H2 + O reaction was determined to be k1b/k1 = 0.17 ± 0.08. The indicated 2σ error includes possible systematic errors due to uncertainties in the rate constants of other reactions that influence the shapes of the CH2 profiles. The present result, which translates to an HCCO yield k1a/k1 = 0.83 ± 0.08, is in excellent agreement with other recent determinations. The above mechanism, with the subsequent reactions that it initiates, also reproduces the measured absolute [C2H2], [O], and [H] profiles with an average accuracy of 5%, thus validating the consistency of the C2H2/O/H reaction model put forward here. © 1994 John Wiley & Sons, Inc.
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  • 177
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    Formation yields of epoxides and O(3P) atoms from the gas-phase reactions of O3 with a series of alkenes (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 945-950 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of ozone with propene, 1-butene, cis-2-butene, trans-2-butene, 2,3-dimethyl-2-butene, and 1,3-butadiene were carried out in N2 and air diluent at atmospheric pressure and room temperature and, by monitoring the formation of the epoxides and/or a carbonyl compound formed from the reactions of O(3P) atoms with these alkenes, the formation yields of O(3P) atoms from the O3 reactions were investigated. No evidence for O(3P) atom formation was obtained, and upper limits to O(3P) atom formation yields of 〈4% for propene, 〈5% for 1.3-butadiene, and 〈2% for the other four alkenes were derived. The reaction of O3 with 1,3-butadiene led to the direct formation of 3,4-epoxy-1-butene in (2.3 ± 0.4)% yield. These data are in agreement with the majority of the literature data and show that O(3P) atom formation is not a significant pathway in O3 - alkene reactions, and that epoxide formation only occurs to any significant extent from conjugated dienes. © 1994 John Wiley & Sons, Inc.
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  • 178
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    Gas-phase kinetics of N-substituted diacetamide (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 951-954 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Gas-phase elimination reactions of number of N-substituted diacetamides have been studied. The rates of N-phenyl, 4-methoxyphenyl, 4-nitrophenyl, and benzyl diacetamide have been measured between 643-683, 642-693, 673-725, and 555-610 K, respectively. They undergo unimolecular first-order elimination reactions, for which log A = 12.8, 12.9, 12.8, and 11.0 s-1 and Ea = 185.7, 191.4, 193.4, and 143.6 kJ mol-1, respectively. The reactivity of these compounds has been compared with the unsubstituted diacetamide at 600 K. The kinetic data reveals that each of the N-aryldiacetamides is less reactive than the parent molecule. We attribute this observation to the resonance of the lone pair of electrons on the nitrogen with either the two carbonyl oxygen atoms or with the 6π electrons in the aromatic ring which will result in the stabilization of the N-aryldiacetamides related to the parent molecules. © 1994 John Wiley & Sons, Inc.
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  • 179
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    Iron(II)-bis (salicyladimine) Schiff-base complexes catalyzed decomposition of hydrogen peroxide (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 955-962 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tetradentate Schiff-base ligands, N,N′-bis(salicylidene)-ethylenediamine (Salen), N,N′-bis(salicylidene) butylenediamine (Salbut), and N,N′-bis(salicylidene)-o-phenylenediamine, (sal-o-phen) are very strongly sorbed by cation exchange resin (Dowex-50W) with Fe2+ ions as a counter ion, forming stable complexes. The kinetics of the catalytic decomposition of H2O2 using these complexes was studied in ethanolic medium. The reaction was first-order with salen and sal-o-phen and second-order with salbut with respect to [H2O2]. The rate of the H2O2 decomposition increased either from salen to salbut or from salen to sal-o-phen. Also, the k (per g dry resin) values decreased with increasing both the particle size and the degree of resin cross-linkage. The active species formed at the beginning of the reaction, had an inhibiting effect on the reaction rate. The corresponding activation parameters were calculated from a least-squares fit of the temperature dependence of the rate constant. A reaction mechanism is proposed. © 1994 John Wiley & Sons, Inc.
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    Kinetics of the reactions of OH with alkanes (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 973-990 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate coefficients for the reactions of OH with ethane (k1), propane (k2), n-butane (k3), iso-butane (k4), and n-pentane (k5) have been measured over the temperature range 212-380 K using the pulsed photolysis-laser induced fluorescence (PP-LIF) technique. The 298 K values are (2.43±0.20) × 10-13, (1.11 ± 0.08) × 10-12, (2.46 ± 0.15) × 10-12, (2.06 ± 0.14) × 10-12, and (4.10 ± 0.26) × 10-12 cm3 molecule-1 s-1 for k1, k2, k3, k4, and k5, respectively. The temperature dependence of k1 and k2 can be expressed in the Arrhenius form: k1 = (1.03 ± 0.07) × 10-11 exp[-(1110 ± 40)/T] and k2 = (1.01 ± 0.08) × 10-11 exp[-(660 ± 50)/T]. The Arrhenius plots for k3 - k5 were clearly curved and they were fit to three parameter expressions: k3 = (2.04 ± 0.05) × 10-17 T2 exp[(85 ± 10)/T] k4 = (9.32 ± 0.26) × 10-18 T2 exp[(275 ± 20)/T]; and k5 = (3.13 ± 0.25) × 10-17 T2 exp[(115 ± 30)/T]. The units of all rate constants are cm3 molecule-1 s-1 and the quoted uncertainties are at the 95% confidence level and include estimated systematic errors. The present measurements are in excellent agreement with previous studies and the best values for atmospheric calculations are recommended. © 1994 John Wiley & Sons, Inc.
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/kin.550261101
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  • 182
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    Kinetics and mechanism of H2O2 decomposition by Cu(II)-, Co(II)-, and Fe(III)-Amine complexes on the surface of Silica-Alumina (25% Al2O3) (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 1055-1061 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the H2O2 decomposition by Cu(II)-, Co(II)-, and Fe(III)-amine complexes supported on the surface of silica-alumina (25% Al2O3) catalyst have been investigated. The decomposition process proceeded with first-order kinetics for the substrate concentration. With copper complexes, in particular, the rate of reaction decreased in the sequence: ethylenediamine (en) 〉 monoethanolamine (mea) 〉 triethanolamine (tea). With ethylenediamine as aligand, the rate has also decreased in the order: Cu(II) 〉 Co(II) 〉 Fe(III). Both of the energy and entropy of activation were found to decrease as: en 〉 mea 〉 tea and for one ligand (en) and different metal ions the sequence was Cu(II) 〉 Co(II) 〉 Fe(III). The decomposition reaction involved the formation of an intermediate active species, which converts into a peroxo-metal-complex of brown or faint red color. The rate of reaction was directly proportional to the [complex], [H2O2], and [H]-1. A mechanism describing the decomposition process is proposed. © 1994 John Wiley & Sons, Inc.
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  • 183
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/kin.550260101
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  • 184
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    Study of the kinetics and equilibrium of the benzyl-radical association reaction with molecular oxygen (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 171-189 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The forward rate constant, k1, and the equilibrium constant, Kp, for the association reaction of the benzyl radical with oxygen have been determined. The rate constant k1 was measured as a function of temperature (between 298 and 398 K) and pressure (at 20 and 760 torr of N2) by two different techniques, argon-lamp flash photolysis and excimer-laser flash photolysis, both of which employed UV absorption spectroscopy (at 253 nm and 305 nm, respectively) to monitor the benzyl radical concentration. Over the range of conditions studied, we find that the reaction is independent of pressure and is almost independent of temperature, which is in accord with two early studies of the reaction but in apparent disagreement with more recent work. For our results in 760 torr of N2 and for 298 〈 T/K 〈 398, a linear least-squares fitting of the data yield the expression: k1 = (7.6 ± 2.4) × 10-13 exp[(190 ± 160)K/T] cm3 molecule-1 s-1. With the flash-photolysis technique, we determined Kp over the temperature range 398-525 K. Experimental values were analyzed alone and combined with theoretically determined entropy values of the benzyl and benzylperoxy radicals to determine the enthalpy of reaction: ΔH298° = (-91.4 ± 4) kJ mol-1. Previous work on the benzyl radical enthalpy of formation allows us to calculate ΔH°f 298 (Benzylperoxy) = (117 ± 6) kJ mol-1. In addition, we carried out an RRKM calculation of k1 using as constraints the thermodynamic information gained by the study of Kp. We find that all the studies of the association reaction are in good agreement once a fall-off effect is taken into account for the most recent work conducted at pressures near 1 torr of helium. © 1994 John Wiley & Sons, Inc.
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  • 185
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    CO2 laser-induced decomposition of propan-2-ol, butan-2-ol, pentan-2-ol, pentan-3-ol, and hexan-2-olThis article is dedicated to the memory of Bob Back, a personal friend and colleague over many years who is sadly missed and to whom we were indebted for valuable discussions during the progress of the work described. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 201-210 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pulsed CO2 laser-induced decompositions of propan-2-ol, butan-2-ol, pentan-2-ol, pentan-3-ol, and hexan-2-ol in the gas phase have been investigated. Like ethanol which we examined previously [1] the absorption cross section of propan-2-ol for pulsed 9R14 radiation increases with pressure at low pressures, an effect attributed to rotational hole-filling. In contrast the absorption cross section of butan-2-ol (10R24) has only a small pressure dependence and those of pentan-2-ol (9R26), pentan-3-ol (10R14), and hexan-2-ol (9P20) show little or no variation with pressure in the range 0.1-5.0 torr.Decomposition products have been investigated at low pressure where the excitation of the alkanols was essentially collision free. The observed products for all the alkanols can be rationalized on the basis of primary dehydration and C—C fission channels, with minor contributions from other molecular eliminations. © 1994 John Wiley & Sons, Inc.
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    Photochemistry of formic acid monomer at 222 nmThis article is dedicated to the memory of our friend and colleague at the National Research Council, Dr. Robert A. Back. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 219-225 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The yields of CO2 and CO formed from the gas-phase photolysis at 222 nm of very low pressures of formic acid where the monomer predominates have been determined using FTIR spectroscopy. The observed ratio of CO2/CO approaches unity as the formic acid pressure approaches zero. Previous studies have shown that the quantum yield for HCOOH + hv → OH + HCO (or H + CO) is 0.70 at 298 K. The present experimental results indicate that the ratio of the quantum yields of the possible molecular photolysis channels forming H2 + CO2 (φ1b) and H2O + CO (φ1c) is ca. 1. Including this result in an analysis of previously reported quantum yields of CO and CO2 determined at higher pressures of formic acid, where both monomer and dimer contribute significantly to the products, indicates that φ1b = φ1c = 0. © 1994 John Wiley & Sons, Inc.
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  • 187
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    Infrared multiphoton decomposition of highly excited t-butyl chloride-d9This article is dedicated to the memory of R.A. (Bob) Back, our mentor and friend. (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 247-257 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The infrared multiphoton decomposition (IR MPD) of t-butyl chloride-d9 as a function of pressure and fluence is reported. The major decomposition route was molecular elimination of DCl in accord with earlier pyrolysis studies. The effect of added gases (2-methyl propene-d8, DCl and 2-methyl propene-h8) on the MPD is presented. This study is a further example of the utility of a new method of analysis of MPD experiments. © 1994 John Wiley & Sons, Inc.
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  • 188
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    Does the HO2 radical react with H2S, CH3SH, and CH3SCH3? (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 355-365 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the title reactions were investigated in a discharge flow tube by using laser magnetic resonance detection of HO2. The upper limits for the bimolecular rate constants for the reactions of HO2 with H2S (k1), CH3SH (k2), and CH3SCH3 (k3) are 〈3 × 10-15, 〈4 × 10-15, and 〈5 × 10-15 cm3 molecule-1 s-1, respectively, at 298 K. Our upper limit for k1 is three orders of magnitude lower than the previously reported value.Measurements at higher temperatures also yield similar upper limits. Our results suggest that HO2 is not an important oxidant for these reduced compounds in the atmosphere. © 1994 John Wiley & Sons, Inc.
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  • 189
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    Gas-phase thermal decomposition of peroxy-N-butyryl nitrate (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 381-387 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas-phase thermal decomposition rate of peroxy-n-butyryl nitrate (n-C3H7C(O)OONO2, PnBN) has been measured at ambient temperature (296 K) and 1 atm of air relative to that of peroxyacetyl nitrate (CH3C(O)OONO2, PAN) using mixtures of PAN (14-19 ppb), PnBN (22-46 ppb), and nitric oxide (1.35-1.90 ppm). The PnBN/PAN decomposition rate ratio was 0.773 ± 0.030. This ratio, together with a literature value of 3.0 × 10-4 s-1 for the thermal decomposition rate of PAN at 296 K, yields a PnBN thermal decomposition rate of (2.32 ± 0.09) × 10-4 s-1. The results are briefly discussed by comparison with data for other peroxyacyl nitrates and with respect to the atmospheric persistence of PnBN. © 1994 John Wiley & Sons, Inc.
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  • 190
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    On the role of transport in the combustion kinetics of a steady-state premixed laminar CO + H2 + O2 flame (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 437-453 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The role of mechanistic steps, diffusion, and their interrelation is explored in a steady-state premixed laminar CO + H2 + O2 flame using a numerical model. Sensitivity coefficients and Green's functions calculated for this system offer systematic characterization of the role of diffusion and exothermicity in carbon monoxide oxidation kinetics. The results reveal that the uncertainties in transport parameters are as important to the model predictions as those in the kinetic steps. The rate controlling steps of the CO + H2 + O2 reaction are found to be different for adiabatic and nonadiabatic premixed flames, and also for systems with and without transport. In particular, the reactions of the hydroperoxyl radical with hydrogen, oxygen, and hydroxyl radicals are found to be important at all temperatures in the fuel lean (40 torr) adiabatic flame studied here. The diffusive mixing of chemical species from the low and the high temperature portions of the flame and the larger heats of reaction associated with the hydroperoxyl radicals are found to be responsible for the increased importance of these reactions. © 1994 John Wiley & Sons, Inc.
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  • 191
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    Gas-phase thermolysis of allyl propargyl amine, allyl cyanomethyl propargyl amine, allyl propargyl 2-thiapropyl amine, and allyl methanesulfonyl propargyl amine (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 487-496 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title amines have been pyrolyzed in a stirred-flow reactor, at temperatures of 360-500°C, pressures of 7-16 torr, and residence times of 0.5-2.9 s, using toluene as carrier gas. The reaction products were allene, propene, and the corresponding imines. The ratio allene:propene varied in the range 6.7-1.6. The amines with CH2CN and SO2CH3 substituents also formed HCN and SO2. These appear to arise from complex free radical decomposition of the imine product. The first-order rate coefficients for the production of allene plus propene followed the Arrhenius equations: Allyl propargl amine: \documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{10.07 \pm 0.31} \exp \left({- 133 \pm 4{\rm kj/mol\,}RT} \right) $$\end{document} Allyl cyanomethyl propargyl amine: \documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{10.73 \pm 0.30} \exp \left({- 146 \pm 4{\rm kj/mol\,}RT} \right) $$\end{document} Allyl propargyl 2-thiapropyl amine: \documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{12.55 \pm 0.38} \exp \left({- 166 \pm 5{\rm kj/mol\,}RT} \right) $$\end{document} Allyl methanesulfonyl propargyl amine: \documentclass{article}\pagestyle{empty}\begin{document}$$ k\left({{\rm s}^{- 1}} \right) = 10^{12.56 \pm 0.34} \exp \left({- 184 \pm 5{\rm kj/mol\,}RT} \right) $$\end{document} Nonconcerted mechanisms, involving polar six center cyclic transition states, are suggested for the elimination of allene and propene. © 1994 John Wiley & Sons, Inc.
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  • 192
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    An analytic hindered rotor model for calculating microcanonical variational unimolecular rate constants from reaction path properties (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 407-419 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A model is proposed for performing microcanonical variational transition state theory calculations which incorporates ideas from vibrator and flexible variational transition state models. Vibrational frequencies, moments of inertia, and potential energy for the variational transition state are found by reaction path following as for the vibrator model. However, the transitional modes are treated as hindered rotors using an analytic potential and an analytic density of states, which are fit to barriers for hindered rotation determined from reaction path following. The model proposed here differs from the flexible transition state model in that the density of states for the transitional modes is analytic and transitional modes and external rotational angular momenta are uncoupled. For the H + CH3 ⇌ CH4 system, rate constants calculated with this new model are only 6-23% smaller on average from those of the flexible transition state model for values of total angular momentum which correspond to average rotational temperatures of 0-2000 K. Harmonic frequencies calculated for the transitional modes from the hindered rotor Hamiltonian are in good agreement with the exact values found by a reaction path analysis. © 1994 John Wiley & Sons, Inc.
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    Kinetics of the acid and alkaline hydrolysis of Monofluorophosphite (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 455-459 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the acid and alkaline hydrolysis of monoflorophosphorous acid has been studied by P-31 NMR and static pH titration over a wide temperature range. The acid catalyzed hydrolysis has a rate constant at 25°C equal to 0.35 dm3 mol-1 s-1 and an activation energy of 53 kJ while the alkaline hydrolysis has a rate constant of 4.6 dm3 mol-1 s-1 and an activation energy of 42 kJ. When the hydrogen in this compound is replaced by either fluorine or a hydroxyl group, the rates of reaction decrease by two orders of magnitude. © 1994 John Wiley & Sons, Inc.
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  • 194
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994) 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260501
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  • 195
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    Kinetics and mechanism of the thermal decomposition reaction of acetone cyclic diperoxide in the gas phase (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 503-509 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the thermal decomposition reaction of gaseous 3,3,6,6-tetramethyl-1,2,4,5-tetroxane (ACDP) in the presence of n-octane was studied in the 403.2-523.2 K temperature range. This reaction yields acetone as the organic product. Under optimum conditions, first-order kinetics were observed, included when the S/V ratio of the Pyrex reaction vessel was increased by a nearly six-fold factor. In the range 443.2-488.2 K the temperature dependence of the rate constants for the unimolecular reaction in conditioned vessels is given by In k1/(s-1) = (31.8 ± 2.5) - [(39.0 ± 2.5)/RT]. The value of the energy of activation in kcal/mol correspond to one O—O bond homolysis of the ACDP molecule in a stepwise biradical initiated decomposition mechanism. At the lower reaction temperatures as well in preliminary experiments participation of a surface catalyzed ACDP decomposition process could be detected. © 1994 John Wiley & Sons, Inc.
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  • 196
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    Hydrolysis of 2-aminoethanethiolsulfate ions (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 545-549 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the acid catalyzed hydrolysis of 2-aminoethanethiolsulfate (AETS) ions were investigated. The dependence of the hydrolysis rate constant on acidity and temperature was determined. The hydrolysis rate equation can be expressed as \documentclass{article}\pagestyle{empty}\begin{document}$$ d{{\left[{{\rm AETS}} \right]} \mathord{\left/ {\vphantom {{\left[{{\rm AETS}} \right]} {dt}}} \right. \kern-\nulldelimiterspace} {dt}} = - k{\rm H}_{\rm o} \left[{{\rm AETS}} \right] $$\end{document} where Ho is the Hammett acidity function. The rate constant, k, can be expressed as The pKa's for the compound were measured and literature value of pKa was found to be in error. The values determined in this study are pKa1 〈 -0.5 and pKa2 = 9.1 ± 0.1. General acid catalysis of the hydrolysis reaction was found not to proceed to a significant degree. © 1994 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
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  • 197
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    Vacuum ultraviolet photolysis of CClF2CH2Cl (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 561-569 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photolysis of CClF2CH2Cl was studied by 147 nm vacuum ultraviolet irradiation. In the presence of NO; CF2CH2, CF2CHCl, and CClF2CN were produced. These products represent three different reaction paths; the molecular dechlorination, molecular dehydrochlorination, and chlorine radical elimination reactions. The reactant pressure and the addition gas (He or NO) pressure effects upon the product yield were studied. © 1994 John Wiley & Sons, Inc.
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  • 198
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    The determination of kinetic data for the reactions of chromium(VI) with glutathione and other thiols (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 587-591 
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    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The equations necessary for the determination of the rate constants corresponding to the opposite elementary steps for formation of the oxidant-reductant ester intermediate, as well as that corresponding to its redox decomposition, in the reduction of chromium(VI) by glutathione and other thiols at physiological pH have been deduced. It is shown that those three rate constants can be obtained with a good reproducibility. © 1994 John Wiley & Sons, Inc.
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    Complex dynamical behavior in the oxidation of hydroxylamine by bromate (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 347-353 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complex dynamical behavior has been observed in the oxidation of hydroxylamine by bromate in acidic sulfate medium. The reaction shows clock type kinetics in closed conditions and an aperiodic oscillations if gaseous products are removed from the system with a constant flow-rate. The reduction kinetics of bromate ions with excess hydroxylamine has been studied in the presence of allyl alcohol. The observed pseudo-first-order rate constant kobs has been found to follow the expression \documentclass{article}\pagestyle{empty}\begin{document}$$ k_{{\rm obs}} = \frac{{kK_1 \left[{{\rm H}^ +} \right]\left[{{\rm hydroxylamine}} \right]}}{{\left({1 + {\rm K}_{\rm 1} \left[{{\rm H}^ +} \right]} \right){\rm K}_{\rm 2}}} $$\end{document} where [hydroxylamine] is total initial hydroxylamine concentration, K1 = 0.5 M-1, K2 = 106 M-1, and k = 2.57 × 103 M-1 s-1 at 298.15 K and I = 2.0 M.The rate constant for the bromine oxidation of hydroxylamine in sulfuric aqueous solution has been determined. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260305
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    Electronic Resource
    Kinetics of solvolysis of 2-chloroquinoxaline (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 403-406 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pseudo-first-order rate constants and activation parameters have been measured for the solvolysis of 2-chloroquinoxaline in various aquo-organic mixtures using methanol, ethanol, and isopropanol as the organic solvent. Excellent linear correlations are found between lnk and the mol fraction of cosolvent and ln[H2O]. The medium effect on the rates of solvolysis is assessed by Grunwald-Winstein's mY correlationship. The estimated values of m (0.55-0.72) and the entropy of activation (148-212 J deg-1 mol-1) for the reactions are well in the range for a bimolecular aromatic substitution reactions. © 1994 John Wiley & Sons, Inc.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260403
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