- Selective photocatalytic conversion of glycerol to hydroxyacetaldehyde in aqueous solution on facet tuned TiO2-based catalysts
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Glycerol is selectively converted to hydroxyacetaldehyde (HAA) and H 2 in aqueous solution on TiO2-based photocatalysts. The product selectivity was verified to be strongly dependent on the facets of TiO2. Rutile with high percentage of {110} facets results in over 90% superior selectivity of HAA, while anatase with {001} or {101} facets gives only 16% and 49% selectivity for HAA, respectively.
- Chong, Ruifeng,Li, Jun,Zhou, Xin,Ma, Yi,Yang, Jingxiu,Huang, Lei,Han, Hongxian,Zhang, Fuxiang,Li, Can
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supporting information
p. 165 - 167
(2014/01/06)
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- Kinetics and mechanism of the oxidation of diols by butyltriphenylphosphonium dichromate
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The oxidation of four vicinal, four non-vicinal diols and one of their monoethers by butyltriphenylphosphonium dichromate (BTPPD), in dimethylsulfoxide (DMSO), resulted in the formation of corresponding hydroxyaldehyde as a main product of the oxidation. The reactions are of first order with respect to BTPPD, however, second order dependence is obtained with respect to each the diol and hydrogen ion. The oxidation of [1,1,2,2-2H 4]ethanediol exhibited primary kinetic isotope effect (k H/kD = 6.61 at 298 K). The temperature dependence of the kinetic isotope effect suggested the symmetrical transition state in the rate-determining step. The rate constants of oxidation of four vicinal diols show excellent correlation with Taft's ∑ σ* values with negative reaction constant, ρz.ast;. The rate of oxidation of ethanediol has been determined in nineteen different solvents. An analysis of the solvent effect indicates the importance of the cation-solvating power of the solvents. A suitable mechanism has been postulated involving the formation of chromate ester in a pre-equilibrium.
- Panday, Dinesh,Kothari, Seema
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experimental part
p. 918 - 925
(2011/09/19)
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- Oxidation of some vicinal and non-vicinal diols by tetrakis(pyridine)silver dichromate: A kinetic and mechanistic study
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The kinetics of oxidation of four vicinal, four non-vicinal diols and two of their monoethers by tetrakis(pyridine)-silver dichromate (TPSD) have been studied in dimethylsulphoxide (DMSO). The main product of oxidation is the corresponding hydroxycarbonyl compound. The reaction is first order in TPSD. Michaelis-Menten type of kinetics is observed with respect to the diols. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence has the form : kobs = a + b (H+]. The oxidation of [1,1,2,2- 2H4] ethanediol exhibits a substantial primary kinetic isotope effect (kH/kD = 5.91 at 298 K). The reaction has been studied in nineteen different organic solvents and the solvent effect has been analysed using Taft's and Swain's multiparametric equations. The temperature dependence of the kinetic isotope effect indicates the presence of a symmetrical transition state in the rate-determining step. A suitable mechanism has been proposed.
- Meena,Daiya,Sharma,Banerji,Kotai,Sharma, Vinita
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experimental part
p. 1887 - 1893
(2012/04/04)
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- Oxidation of some vicinal and non-vicinal diols by morpholinium chlorochromate: A kinetic and mechanistic study
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The kinetics of oxidation of four vicinal, four non-vicinal diols and two of their monoethers by morpholinium chlorochromate (MCC) have been studied in dimethylsulphoxide (DMSO). The main product of oxidation is the corresponding hydroxycarbonyl compound. The reaction is first order in MCC and the diols. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence is taking the form : kobs = a + b [H+]. The oxidation of [1,1,2,2-2H4]ethanediol exhibits a substantial primary kinetic isotope effect (kH/kD = 5.82 at 298 K). The reaction has been studied in nineteen different organic solvents and the solvent effect has been analysed using Taft's and Swain's multiparametric equations. The temperature dependence of the kinetic isotope effect indicates the presence of a symmetrical transition state in the rate-determining step. A suitable mechanism has been proposed.
- Barthora,Baghmar,Agarwal,Sharma, Vinita
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experimental part
p. 677 - 683
(2012/04/10)
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- Kinetics and mechanism of iridium(III) catalyzed oxidation of ethylene glycol by Cerium(IV) in sulfuric acid media
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The kinetics and mechanism of trace iridium(III) catalyzed oxidation of ethylene glycol by cerium(IV) in sulfuric acid media has been investigated by titrimetric technique of redox in the temperature range of 298-313K. The reaction is first order with respect to Cc(IV) and Ir(III), and a positive fractional order with respect to EG. It is found that the pseudo-first order ([EG]?[Ce(IV)]?[Ir(IIl)]) rate constant, kobs, decreases with the increase of [HSO4-] and increases with the increase of [H+]. Under nitrogen atmosphere, the reaction system can initiate polymerization of acrylonitrile, indicating the generation of free radicals. On the basis of the experimental results, a reasonable mechanism has been proposed. Rate equations derived from this mechanism can explain all the experimental results. From the dependence of kobs on the concentration of HSO 4-, the kinetically active species has been found to be Ce(SO4)2. The rate constants of the rate determining step and the activation parameters have been evaluated.
- Bai, Wei-Song,Zhai, Yong-Qing,Liu, Hong-Mei,Lue, Hong-Ying,Song, Wen-Yu
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body text
p. 1194 - 1198
(2009/03/11)
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- Oxidation of diols by cetyltrimethylammonium dichromate
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The oxidation kinetics of some diols have been investigated using cetyltrimethylammonium dichromate as the oxidant in dichloromethane in the presence of acetic acid and a cationic surfactant. A tentative mechanism has been proposed on the basis of (i) observed rate constant dependencies on the reactants, (ii) high negative entropy change and (iii) the kobs dependencies on surfactant concentration.
- Patel, Sabita,Sung, Dae Dong,Mishra
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experimental part
p. 1218 - 1221
(2009/03/11)
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- Oxidation of unactivated primary aliphatic amines catalyzed by an electrogenerated 3,4-azaquinone species: A small-molecule mimic of amine oxidases
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High catalytic performance of the electrogenerated amine oxidase mimic 3,4-iminoquinone 1ox is observed under metal-free conditions in the chemoselective oxidation reaction of unactivated primary aliphatic amines.
- Largeron, Martine,Neudorffer, Anne,Fleury, Maurice-Bernard
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p. 1026 - 1029
(2007/10/03)
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