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  • 1
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of the decomposition of hydrogen peroxide catalyzed by Mn(II)-bis-salicylaldimine complexes (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 393-399 
    Details
    ISSN: 1434-4475
    Keywords: Hydrogen peroxide ; Manganese ; TetradentateSchiff base ; Kinetics ; Decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die teradentatenSchiffschen Basen N,N′-bis-Salicyliden-ethylendiamin (salen), N,N′-bis-Salicyliden-Hexylendiamin (salhex) und N,N′-bis-Salicyliden-o-phenylendiamin (sal-o-phen) werden von Kationenaustauschen (Dowex-50W) mit Mangan(II) als Gegenion unter der Bildung stabiler Komplexe adsorbiert. Die Kinetik der katalytischen Zersetzung von H2O2 in Gegenwart dieser Komplexe wurde in wäßrigem Medium untersucht. Die Zersetzungsreaktion ist erster Ordnung bezüglich H2O2 in den Fällensalen undsal-o-phen und dritter Ordnung im Fall vonsalhex. Die Reaktionsgeschwindigkeit steigt mit der Länge der Methylenkette des Liganden und mit dessen Raumbedarf und wird von der Aktivierungsentropie bestimmt. Ein Reaktionsmechanismus wird vorgeschlagen.
    Notes: Summary The tetradentateSchiff bases N,N′-bis(salicylidene) ethylenediamine (salen), N,N-bis-(salicylidene) hexylenediamine (salhex), and N,N′-bis(salicylidene)-o-phenylenediamine (sal-o-phen) are very strongly adsorbed by cation exchange resins (Dowex-50W) with manganese(II) as a counter ion, forming stable complexes. The kinetics of the catalytic decomposition of H2O2 in presence of these complexes has been studied in aqueous medium. The decomposition reaction is first order with respect to H2O2 in the case ofsalen andsal-o-phen and third order in the case ofsalhex. The greater the ligand methylene chain length or the greater the steric effect of the ligand, the greater will be the rate of reaction. The reaction is governed by the entropy of activation. A reaction mechanism is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00813201
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  • 2
    Electronic Resource
    Electronic Resource
    Heterogeneous decomposition ofp-methoxy- andp-methyl-dibenzoyl peroxides by a montmorillonite amine intercalate (1986)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 4 (1986), S. 169-175 
    Details
    ISSN: 1573-1111
    Keywords: Montmorillonite ; decomposition of organic peroxides ; heterogeneous catalysis and benzidine reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A kinetic study of the heterogeneous thermal decomposition ofp-MeO-DBP andp-Me-DBP catalysed by the montmorillonite benzidine intercalate has been made. The kinetics of decomposition were observed to follow a three-halves order reaction with respect to the peroxides. The activation parameters in heterogeneous media have lower values compared with the corresponding values in homogeneous ones. The relationships between ΔH * and ΔS * were plotted and show two converging straight lines which indicate that both electron donating and withdrawing substituents on the peroxide enhance the rate of decomposition under these conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655931
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  • 3
    Electronic Resource
    Electronic Resource
    Kinetics of heterogeneous decomposition of hydrogen peroxide (1986)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 4 (1986), S. 359-367 
    Details
    ISSN: 1573-1111
    Keywords: H2O2 decomposition ; Wofatit KPS-resin ; Cu(II)-ammine complex ions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of the decomposition of hydrogen peroxide was studied in aqueous medium in the temperature range 25–40°C in the presence of Wofatit KPS-resin in the form of Cu(II)-ammine complex ions. The rate constant was deduced at various degrees of resin cross-linkage and different concentrations of hydrogen peroxide. The order of the decomposition reaction varied from first order to half order, i.e., the order of the reaction decreased with increasing the concentration of H2O2. The decomposition process was found to be a catalytic reaction which was controlled by the chemical reaction of H2O2 molecules with the active species inside the resin particles. The mechanism of the reaction can be summarized by the equation $$ - {\text{d}}\left[ {{\text{H}}_{\text{2}} {\text{O}}_{\text{2}} } \right]/{\text{d}}t = k_1 {\text{ }}\sqrt {K_1 } K_2 \left[ {{\text{H}}_{\text{2}} {\text{O}}_{\text{2}} } \right]\left[ {{\text{Cu}}\left( {{\text{NH}}_{\text{3}} } \right)_4 } \right]^{2{\text{ }} + } /\left[ {{\text{H}}^{\text{ + }} } \right]$$ in which the subsequent reactions of the probable active complex are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656163
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  • 4
    Electronic Resource
    Electronic Resource
    Catalytic decomposition of organic peroxides by 4,4′-diamino-trans-stilbene (DTS)/montmorillonite complex: II.p-nitro andp-methyl dibenzoyl peroxide (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 675-682 
    Details
    ISSN: 1573-1111
    Keywords: Organic peroxide reactions ; montmorillonite/4,4′-diaminostilbene intercalate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of the induced decomposition ofp-NO2- andp-CH3-dibenzoyl peroxide in the presence of 4,4′-diamino-trans-stilbene (DTS) were studied in ethanol under both homogenous and heterogeneous conditions. The heterogeneous reaction was carried out in the presence of the DTS/montmorillonite complex. The decomposition reaction was found to be second order and three-halves order for the peroxide concentration in homogeneous and heterogeneous systems, respectively. The reaction was first order for the amine concentration in the homogeneous system. The activation energies for the decomposition reaction were obtained as 54.7±2 and 59.5±3 kJ mol−1 forp-NO2- andp-CH3-dibenzoyl peroxides, respectively, in the homogeneous systems and are higher than the corresponding values of 41±1.5 and 47.6±1 kJ mol−1 for thep-NO2 andp-CH3 derivatives in heterogeneous media.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656586
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  • 5
    Electronic Resource
    Electronic Resource
    Oxidation kinetics of p-aminodiphenylamine with peroxydisulphate (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 609-614 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of oxidation of p-aminodiphenylamine with the peroxydisulphate ion were investigated spectrophotometrically. The oxidation was accompanied by the appearance of a wine-red colour, which changed to become colourless. The reaction rate was measured by the stopped-flow technique with a UV spectrophotometer. The reactions proceeded with second-order kinetics, first-order for each individual reactant. Cationic micelles (cetyltrimethyl ammonium bromide) caused an enhancement in the reaction rate followed by inhibition at higher concentrations. Anionic micelles (sodium dodecyl sulphate), on the other hand, had a slightly retarding effect. The effects of radical scavenger, pH and ionic strength on the fast oxidation rate were examined. A mechanism consistent with the observations is discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061103
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  • 6
    Electronic Resource
    Electronic Resource
    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.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260910
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