Hydrogen peroxide propylene epoxidation

Key Words Reaction-controlled phase-transfer catalysis, 2-ethylanthrahydroquinone, Hydrogen peroxide. Propylene, Propylene oxide (PO), Cyclohexene, Cyclohexene oxide, Allyl chloride, Epichlorohydrin, Epoxidation. 2008 Elsevier B.V. 

Epoxidation with hydrogen peroxide has also been tried. The epoxidation reaction is catalyzed with compounds of As, Mo, and B, which are claimed to produce propylene oxide in high yield ... 

A particularly interesting system for the epoxidation of propylene to propylene oxide, working under pseudo-heterogeneous conditions, was reported by Zuwei and coworkers [61]. The catalyst, which was based on the Venturello anion combined with long-chained alkylpyridinium cations, showed unique solubility properties. I11 the presence of hydrogen peroxide the catalyst was fully soluble in the solvent, a 4 3 mixture of toluene and tributyl phosphate, but when no more oxidant was left, the tungsten catalyst precipitated and could simply be removed from the... 

R. Meiers, and W. F. Holderich, Epoxidation of propylene and direct synthesis of hydrogen peroxide by hydrogen and oxygen, Catal. Lett. 59, 161-163 (1999). 

Sometimes, due to special conditions, chain transformation may hardly be induced. An example of this is the reaction of propylene epoxidation. However, intense generation of active sites (H02) in the primary reaction gives the possibility of suppressing acceptor chain transformation to undesired products and simultaneously stimulating the main direction—epoxidation. This is obtained due to chemical induction, which induces and speeds up selective transformation of propylene (acceptor) to a quite high rate. The authors have implemented such a conjugation mechanism in propylene epoxidation by hydrogen peroxide [10]. 

Conjugated propylene epoxidation with hydrogen peroxide is the main reaction proceeding in the temperature range of 500-580 °C under optimal conditions the average propylene oxide yield reaches 50%. 

It is common knowledge that the rate of epoxidation by alkylperoxy radicals is defined by their structure. The simplest representative and the parent radical of this class is the HO radical. In the case of propylene epoxidation with hydrogen peroxide in the gas phase at 500-580 °C and contact time r = 4.4 s, the epoxidating particle is, probably, the HO radical whose activity in the absence of catalysts is higher than the RO activity. 

The number of catalytic cycles (v) in propylene epoxidation reaction with hydrogen peroxide... 

Effective kinetic and thermodynamic parameters of propylene epoxidation with hydrogen peroxide on biomimic (perFTPhPFe(III)0H/Al203)... 

This technology could also be applied for the oxidation of methane (70 °C, 5 Mpa) to formic acid (46% selectivity based on hydrogen peroxide). Another catalyst which can be applied for the direct oxidation of benzene with H202 is the TS-1 catalyst, as described above for propylene epoxidation [41]. Conversion is generally kept low, because introduction of a hydroxy group activates the aromatic nucleus to further oxidation to hydroquinone, catechol and eventually to tarry products [137]. 

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