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  • 1
    Electronic Resource
    Electronic Resource
    A Kinetic Study of the Cyclohexadienyl Radical. I. Disproportionation and Combination with the Isopropyl Radical (1964)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 86 (1964), S. 5424-5429 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01078a012
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  • 2
    Electronic Resource
    Electronic Resource
    The Reactivity of the Cyclic Polyenes toward Free Radicals. IV. Cyclohexadiene-1,3 and the Isopropyl Radical (1965)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 69 (1965), S. 2362-2367 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100891a041
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  • 3
    Electronic Resource
    Electronic Resource
    Reactions of the Ethyl Radical. VIII. A Molecular Orbital Approach to the Energetics of the Addition Reaction (1966)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 70 (1966), S. 2191-2201 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100879a019
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  • 4
    Electronic Resource
    Electronic Resource
    The polymerization of acrylonitrile in aqueous solution (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 34 (1959), S. 209-228 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of polymerization of acrylonitrile in aqueous solution when initiated (a) by Fenton's reagent and (b) photochemically using various photosensitizers have been determined dilatometrically over a wide range of conditions. Whenever ferric salts are either present initially or generated in situ, some polyacrylonitrile radicals (S*) are always destroyed by the reaction; $$ S_j^* + {\rm Fe}({\rm III}) \to p_j + {\rm Fe}({\rm II}) $$ for which k = 6.7 × 10-5 exp { -2.3 kcal./RT} . mole-1 sec.-1. Reaction (1) may be suppressed by addition of fluoride ion. When Fe3+OH- is used as the photosensitizer for 3130 A. light, the intensity exponent x is given by 1 〉 x 〉 0.5, being larger the greater [Fe(III)]. This effect is also due to reaction (1) competing with mutual termination, and measurements of d[Fe(II)]/dt confirm this and lead to values of the primary quantum yeild in agreement with published values. The rotating sector technique can be applied and gives kp = 3 × 107 exp { -4.1 kcal./RT} and kt = 3 × 1013 exp { -5.4 kcal./RT} l. mole-1 sec.-1. From observations of the small photo after-effect, the “build up” to the steady state in both (a) and (b) above, and the effect of mechanical agitation on all these phases of the reaction, it is concluded that some of the observed rate is due to polymerization of radicals buried in polymer particles, P* (one radical per particle) utilizing adsorbed monomer. In mechanically undisturbed systems, P* particles are constant in number throughout the steady state, decay slowly and bimolecularly during the after-effect, but are not oxidized by Fe(III). The presence of these particles is responsible for the changing order with respect to [m1] from two to unity as [m1] is increased. The value of [m1]c, the concentration at which this changae of order takes place, is dependent on the rate of initiation and air temperature in a way which reconciles previously published conflicting rate equations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1203412718
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  • 5
    Electronic Resource
    Electronic Resource
    The polymerization of acrylonitrile in aqueous solution. Part II. The reaction photosensitized by Fe3+, Fe3+OH-, Fe2+, and I- ions (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 39 (1959), S. 299-312 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerization of acrylonitrile in aqueous solution photosensitized by Fe2+, Fe3+OH-, and I- has been determined dilatometrically at 25°C. After an acceleratory phase caused partly by increasing intensity of absorbed light due to light-scattering by the insoluble polymer particles, a steady rate Rp is established and continues up to ∼10% conversion. Rp is proportional to Iabs[m1]1.0, where x is slightly greater than 0.5 unless ferric ions are present which may oxidize and terminate polyacrylonitrile radicals and cause x to be greater than 0.5. In accordance with earlier measurements, φ for the reaction \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Fe}^{3 +} {\rm OH}- {{{3130\ {\rm A}.} \atop {-\hskip-4pt-\hskip-4pt-\hskip-4pt-\hskip-4pt-\hskip-4pt-\hskip-4pt-\hskip-5pt\longrightarrow}}\atop{}}{\rm Fe}^{2 +} + {\rm OH}$$\end{document} is found to be 0.15. Propagation occurs by addition (a) of dissolved monomer molecules to polymer radicals S* (kp = 1.45 × 104 l. mole-1 sec.-1) and (b) of adsorbed monomer molecules to the radical in suspended polymer particles P* which contain several polymer molecules and one growing radical. S* radicals are subject to mutual termination (kt = 2 × 109 l. mole-1 sec.-1) and oxidative termination by ferric ion (k4 = 1.3 × 104 l. mole-1 sec.-1). As soon as the steady state is established [P*] is constant, but after stopping irradiation [P*] decays slowly and bimolecularly and therefore gives rise to a small aftereffect. Agitation causing the polymer suspension to coagulate (a) reduces Rp due to changes in Iabs and a decrease in the number of particles and (b) decreases the half-life of the aftereffect by increasing the rate of mutual destruction of P* particles.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1203913523
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  • 6
    Electronic Resource
    Electronic Resource
    Radical displacement in allyl ester polymerization. I. Allyl acetate; evidence from gas-phase kinetics (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 75-80 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photolysis of diethyl ketone in the presence of allyl acetate in the range 35-175°C. leads to the addition and dismutation reactions: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{c} {\rm CH}_3 {\rm CH}_2^ \cdot + {\rm CH}_2 \hbox{=\hskip-1.5pt=}{\rm CHCH}_2 {\rm OCOCH}_3 \displaystyle{{{{k_7}\atop \to}\atop {}}}{\rm tCH}_3 {\rm CH}_2 {\rm CH}_2 {\rm \dot CHCH}_2 {\rm OCOCH}_3\\ {\rm CH}_3 {\rm CH}_2 {\rm CH}_2 {\rm \dot CHCH}_2 {\rm OCOCH}_3 \displaystyle{{{{k_8}\atop \to}\atop {}}}{\rm C}_5 {\rm H}_{10} + {\rm CO}_2 + {\rm CH}_3\\ \end{array}$$\end{document} The proposed reaction scheme is supported by the values: R(CO2)/[R(C5H10) + R(C4H8)] = 1.02 ± 0.03, and R(C5H10)/[R(CH4) + R(C3H8)] = 1.01 ± 0.03, and allows the evaluation of k7 and k8: \documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{*{20}c} {k_7 /k_2 ^{1/2} = 10^{(- 7.2 \pm 0.4)} \exp \{- 7.7 \pm 0.6\} 10^3 /RT} \hfill & {({\rm cm}.^3 /{\rm mol}.\sec .)^{1/2}} \hfill \\ {k_8 k_2 ^{1/2} /k_{7{\rm a}} = 10^{(14.5 \pm 0.5)} \exp \{- 15.8 \pm 1.0\} 10^3 /RT} \hfill & {({\rm mol}./{\rm cm}.^3 \sec .)^{1/2}} \hfill \\ \end{array} $\end{document} where k2 refers to: 2CH3CH·2 → C4H10 and k7a to: CH3CH·2 + ·C5H10OCOCH3 → C7H15OCOCH3. These results are discussed in relation to the radical displacement mechanism of effective chain transfer in the polymerization of allylic monomers.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030109
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  • 7
    Electronic Resource
    Electronic Resource
    The copolymerization of crotononitrile and styrene. I. Trans-crotononitrile: The penultimate unit effect (1964)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 2 (1964), S. 991-997 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1964.110021015
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  • 8
    Electronic Resource
    Electronic Resource
    A quantitative study of alkyl radical reactions by kinetic spectroscopy. II. Combination of the methyl radical with the oxygen molecule (1972)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 4 (1972), S. 129-149 
    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 \documentclass{article}\pagestyle{empty}\begin{document}$${\rm CH}_{\rm 3} + {\rm O}_{\rm 2} (+ {\rm M}) \to {\rm CH}_{\rm 3} {\rm O}_{\rm 2} {\rm (+ M)}$$\end{document} have been studied, using the technique of flash photolysis and kinetic spectroscopy to follow the methyl radical concentration. The order of the reaction lies between 2 and 3 throughout the range of pressure from 25 to 380 torr at 22°C, and the results are consistent with a single reaction sequence: \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{l} {\rm CH}_{\rm 3} + {\rm O}_{\rm 2} \mathop {{\rm \rightleftharpoons}}\limits_{\rm b}^{\rm a} {\rm CH}_{\rm 3} {\rm O}_{\rm 2} ^* \\ {\rm CH}_{\rm 3} {\rm O}_{\rm 2} ^* {\rm } + {\rm M}\mathop {{\rm \rightarrow}}\limits^{\rm c} {\rm CH}_{\rm 3} {\rm O}_{\rm 2} {\rm + M} \\ \\\end{array}$$\end{document} The limiting values of the third-order rate coefficients at low pressures are (3.6±0.3) × 1011 1.2 mole-2 sec-1 when M is neopentane, and (0.94 ± 0.03) × 1011 1.2 mole-2 sec-1 when M is nitrogen. The limiting value of the second-order rate coefficient at high pressures is (3.1 ± 0.3) × 108 1. mole-1 sec-1. The rate constant for the independent second-order reaction \documentclass{article}\pagestyle{empty}\begin{document}$${\rm CH}_{\rm 3} + {\rm O}_{\rm 2} \to {\rm CH}_{\rm 2} {\rm O} \to {\rm OH}$$\end{document} is shown to be not much greater than 2 × 105 1. mole-1 sec-1, so that this reaction does not complete significantly with the combination reaction.This new interpretation is contrary to currently accepted views.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550040202
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  • 9
    Electronic Resource
    Electronic Resource
    A kinetic study of the reactions of the hydrogen atom with the cyclohexadiene isomers in the gas phase (1974)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 6 (1974), S. 337-357 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Absolute values of the rate constants for the reaction of hydrogen atoms with cyclic olefins in the gas phase have been measured in a discharge-flow system under 3.5, 16, and 22 torr Ar at 23°C. The attenuation of hydrogen atom concentration in the reaction tube in the presence of a large excess of olefin was measured with an ESR spectrometer, and the products were analyzed by gas chromatography. Cyclic C6 hydrocarbons were the only significant products obtained when the hydrogen atom concentration was 2.6 × 10-10 mole/1., the olefin concentration was in the range of 9 to 22 × 10-8 mole/1., and the pressure was 16 torr Ar. The values for the rate constants for reaction with cyclohexadiene-1,3, cyclohexadiene-1,4, and cyclohexene are, respectively, (9 ± 2) × 108, (12 ± 1) × 108, and (6 ± 1) × 108 l./mole-sec, and they are not changed significantly by a sixfold change in total pressure. The fraction of the total interaction that proceeds by addition is 84% in the cyclohexadiene-1,3 system, but only 18% in the cyclohexadiene-1,4 system, and the cyclohexadienyl radical is therefore the dominant radical species in the latter system. The pattern of interaction between the hydrogen atom and the cyclohexadienyl radical was determined, and comprises 65% of disproportionation, and 13% and 23% of combination to yield cyclohexadiene-1,3 and cyclohexadiene-1,4, respectively. These results are consistent with the general patterns of reactivity emerging from studies of the reactions between free radicals and olefins in related systems.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550060305
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  • 10
    Electronic Resource
    Electronic Resource
    The ethylperoxy radical spectrum and rate constant for mutual interaction measured by flash photolysis and kinetic spectroscopy (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 11 (1979), S. 1211-1229 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Intrinsic spectral and kinetic parameters have been measured for the ethylperoxy radical, which was formed in the gas phase by the flash photolysis of azoethane in the presence of an adequate excess of oxygen. Absolute values of the extinction coefficient ∊(λ) were derived from complementary measurements of the yield of nitrogen and the absorbance of an equivalent concentration of ethylperoxy radicals. The absorption spectrum is broad, structureless and comparatively weak; ∊(236) = 1.02 × 103 liter mole-1 cm-1 at the maximum, and the oscillator strength is 3.4 × 10-2. This spectrum resembles the spectrum of the methylperoxy radical closely in form, but it is less intense; the ratio of the values of oscillator strength is 0.5. The bimolecular reactions of mutual interaction of ethylperoxy radicals are not exclusively terminating, and ethoxy and hydroperoxy radicals are formed in kinetically significant quantities. A computer program was designed to simulate the rise and fall of the concentration of each radical species, and to perform the related kinetic analysis. This program predicted that a second-order plot of the decline of the absorbance of the ethylperoxy radical during the dark period would not show a significant departure from linearity, a conclusion which was confirmed by experiment. Accordingly, the gradient of each such plot yielded a value of k'/∊(λ), where k' is the apparent value of the rate constant for the collective reactions of mutual interaction. This rate constant was evaluated from the product of corresponding values of k'/∊(λ) and ∊(λ); individual values are independent of the wavelength of measurement, and the mean value is k' = (6.6 ± 0.5) × 107 liter mole-1 sec-1. Further kinetic analysis yielded the corresponding absolute value: k = (6.0 ± 0.6) × 107 liter mole-1 sec-1. This value fits the pattern of a relationship between rate constant and structure shown by the methylperoxy, isopropylperoxy, and tert-butylperoxy radicals. Adequate sensitivity for the characterization of the spectrum of the ethylperoxy radical was achieved by the use of a pulsed xenon arc as the monitoring light source in conjunction with a dual beam detection system with twin cells and balanced photomultipliers, and the apparatus is described in detail.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550111107
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