3071-32-7Relevant academic research and scientific papers
Hydrogen Bonding in α-Phenylethyl Hydroperoxide
Danoczy, E.,Holly, S.,Jalsovszky, G.,Gal, D.
, p. 1190 - 1194 (1984)
The H-bonded associates of α-phenylethyl hydroperoxide (HROOH) were investigated in CCl4, at various concentrations (0.788 X 1E-3 - 960 X 1E-3 M) and temperatures (22-75 deg C), by using IR spectroscopic methods.A very stable intramolecular OH..? bond was observed with a low enthalpy value.Above a concentration of 50 X 1E-3 M cyclic dimers and trimers were found, the latter with the lowest thermal stability.The corresponding thermodynamic parameters have been calculated.
Temperature effect on the rate of formation of free radicals in CTAB-catalyzed decomposition of hydroperoxides
Pisarenko,Maksimova,Kartasheva,Kasaikina
, p. 1500 - 1503 (2003)
The temperature effect on the rate of the decomposition of hydroperoxides and the rate of the formation of free radicals in the oxidation of ethylbenzene with molecular oxygen in the presence of α-phenylethyl hydroperoxide-cetyltrimethylammonium bromide (CTAB) as a catalytic system for free radical generation was studied by kinetic methods (from the oxygen consumption and hydroperoxide decomposition rates) and the inhibition method involving different acceptors of free radicals.
Photooxidation of ethylbenzene with TiO2 and metal coated TiO2 and its kinetics
Habibi, Mohammad H.,Isfahani, A. Zeini,Mohammadkhani,Montazerozohori
, p. 1121 - 1127 (2004)
Photooxidation of ethylbenzene with oxygen to give ethylbenzene hydroperoxide has been achieved in a stirred photochemical reactor that was cooled by a water system by irradiation with a 400 W high-pressure mercury lamp and using TiO2 powder and metal coated TiO2. The effects of the amount of copper or silver coated on TiO2 and of the temperature on the rate of oxidation have been investigated. It is suggested that thermal cleavage of the O-O bond and photochemically generated singlet oxygen should be considered as the initiating step in a radical chain mechanism. An optimum loading of 6% Ag or 4-5% Cu was observed for photooxidation of ethylbenzene. Springer-Verlag 2004.
Selective side-chain oxidation of alkyl aromatic compounds catalyzed by cerium modified silver catalysts
Beier, Matthias J.,Schimmoeller, Bjoern,Hansen, Thomas W.,Andersen, Jens E.T.,Pratsinis, Sotiris E.,Grunwaldt, Jan-Dierk
, p. 40 - 49 (2010)
Silver supported on silica effectively catalyzes the aerobic side-chain oxidation of alkyl aromatic compounds under solvent-free conditions. Toluene, p-xylene, ethylbenzene and cumene were investigated as model substrates. Typically, the reaction was performed at ambient pressure; only for toluene an elevated pressure was required. Carboxylic acids, such as benzoic acid or p-toluic acid, additionally increased the reaction rate while CeO2 could act both as a promoter and an inhibitor depending on the substrate and the reaction conditions. Silver catalysts were prepared both by standard impregnation and flame spray pyrolysis. Addition of a Ce precursor to the FSP catalyst resulted in significantly smaller silver particles. Ce-doped FSP catalysts in general exhibited a superior catalytic performance with TONs up to 2000 except for cumene oxidation that appeared to proceed mainly by homogeneous catalysis. In addition, flame-made catalysts were more stable against silver leaching compared to the impregnated catalysts. The structure of the silver catalysts was studied in detail both by X-ray absorption spectroscopy and transmission electron microscopy suggesting metallic silver to be required for catalytic activity. Catalytic studies point to a radical mechanism which differs depending on the type of substrate.
Inhibition of the oxidation of styrene epoxide by potassium iodide and bromide in an acidic solution
Petrov,Solyanikov
, p. 154 - 157 (2010)
The inhibiting action of potassium iodide and bromide on the oxidation of the binary system of styrene epoxide + p-toluenesulfonic acid and on the hydroperoxide decomposition in the presence of the binary system was revealed. The inhibition mechanism is complex. During the course of the inhibition, the active form of the inhibitor is regenerated, which interacts, according to the kinetic data, with the transient species formed in the binary mixture.
In situ formed Co clusters in selective oxidation of Α-C–H bond: Stabilizing effect from reactants
Wang, Zhijie,Guan, Anxiang,Kung, Mayfair C.,Peng, Anyang,Kung, Harold H.,Lv, Ximeng,Zheng, Gengfeng,Qian, Linping
, p. 1 - 7 (2019)
Aerobic oxidation of α-C–H bond of organic compounds to valuable chemicals is widely investigated in both fundamental research and industry. Due to the good stability of molecular oxygen, severe reaction conditions are generally required. Herein, by in situ synthesis we used molecular oxygen to induce cobalt nanoclusters with the sensitive catalysis in mild selective oxidation. The cobalt containing clusters with an average diameter around 0.9 nm are in situ prepared in the presence of cis-cyclooctene epoxidation and cyclooctene dimer oxide is formed at the interface to stabilize Co clusters with electron donation as an oil-soluble surfactant. The soluble clusters exhibit high activity in selective oxidation of α-C–H bond of ethylbenzene into acetophenone and turnover number (TON) reaches about 7 × 104 during 50 h’ reaction at 373 K, which is around 960 times more active than the one using CoCl2 salt as the catalyst, resulting from efficient mass transportation, π bond interaction and oxygen gas activation. Extended work based on this understanding demonstrates that cobalt nanoclusters also effectively catalyze aerobic oxidation of cyclohexene.
An Improved Catalytic Performance of Fe(III)-promoted NHPI in the Oxidation of Hydrocarbons to Hydroperoxides
Kuznetsova,Kuznetsova,Yakovina,Karmadonova,Bal’zhinimaev
, p. 1020 - 1027 (2020)
Abstract: N-hydroxyphthalimide (NHPI) is a promising catalyst in aerobic oxidation of hydrocarbons to corresponding hydroperoxides. We have found that a trace amount of Fe(benz)3 or Fe(acac)3 (in concentration of less than 10?1 mmol/l and with the ratio of Fe(III): NHPI = 1:500) considerably accelerates the oxidation of cyclohexene and ethylbenzene, while retaining the selectivity to hydroperoxides at a level of 90%. As a consequence, the reaction temperature could be lowered down to 50–60?°C. The promoting effect of the additives was attributed to the ability of Fe(III) complexes to generate phthalimido-N-oxyl radicals (PINO) without participation in any transformations of hydrocarbon intermediates and hydroperoxides, thus ensuring selective formation and stability of the hydroperoxides.
An experimental and theoretical study of the catalytic effect of quaternary ammonium salts on the oxidation of hydrocarbons
Barrio,Toribio,Campos-Martin,Fierro
, p. 11527 - 11532 (2004)
The enhancement in the autoxidation of ethylbenzene by molecular oxygen in the presence of quaternary ammonium salts (QAS) was investigated from the experimental and theoretical points of view. The primary effect of the addition of QAS to the reaction medium was an increase in ethylbenzene conversion. Quantum chemical calculations, using B3LYP hybrid functional, revealed a weakening of C-O and O-H bonds of the hydroperoxide. These effects favor the formation of ethylbenzenyl and peroxyl radicals, respectively, both of which are involved in the propagation reaction that leads to the formation of hydroperoxide, the desired final product. Analysis of the electronic properties of the structures formed between reactants and catalysts offers a better understanding of the mechanism of ethylbenzene oxidation reactions. The atoms-in-molecules approach enables a rigorous description of atomic charges and bond properties that can be qualitatively related to the experimental data.
New Understanding of Selective Aerobic Oxidation of Ethylbenzene Catalyzed by Nitrogen-doped Carbon Nanotubes
Su, Yongzhao,Li, Yuhang,Chen, Zhicheng,Huang, Jiangnan,Wang, Hongjuan,Yu, Hao,Cao, Yonghai,Peng, Feng
, p. 646 - 655 (2020/12/04)
Selective aerobic oxidation of hydrocarbons undergoes a free-radical chain reaction to yield corresponding value-added products is the significant process in the chemical industry. Nanocarbons with heteroatoms doping as free-metal catalysts have been prov
Mixed hetero-/homogeneous TiO2/N-hydroxyimide photocatalysis in visible-light-induced controllable benzylic oxidation by molecular oxygen
Krylov, Igor B.,Lopat'eva, Elena R.,Nikishin, Gennady I.,Subbotina, Irina R.,Terent'ev, Alexander O.,Yu, Bing
, p. 1700 - 1711 (2021/06/28)
Homogeneous and heterogeneous types of catalysis are frequently considered as separate disciplines or even opposed to each other. In the present work, a new type of mixed hetero-/homogeneous catalysis was demonstrated for the case of selective alkylarene
