Reaction-controlled phase-transfer

Commercially available 30% hydrogen peroxide solution can oxidize alkenes readily in the presence of a carbo-diimide promoter <1996SL649, 1998JOC2564, 1998JOC1730> (Equation 67). A method to epoxidize propene using aqueous hydrogen peroxide and a reaction controlled phase-transfer catalysts was developed <20040PD131>. 

X. Zuwei, Z. Ning, S. Yu, L. Kunlan, Reaction-controlled phase-transfer catalysis for propylene epoxidation to propylene oxide. Science 292, 1139-1141 (2001). 

Reaction-Controlled Phase-Transfer Catalyst Based on Quaternary Ammonium Phosphotungstates 431... 

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. 

Reaction-Controlled Phase-Transfer Catalysis for Epoxidation of Olefins... 

This chapter will present recent progress made in reaction-controlled phase-transfer catalysis for the epoxidation of olefins, focusing on work with hetero-pol)q5hosphotungstates and quaternary ammonium ions from our group. We have systemically investigated the influence of composition of the heteropoly anion and various quaternary ammonium ions on the catalyst activity. The epoxidation of propylene, allyl chloride, and others olefins and the stability of the catalyst in recycle will be summarized and discussed in detail. 

REACTION-CONTROLLED PHASE-TRANSFER CATALYST BASED ON QUATERNARY AMMONIUM PHOSPHOTUNGSTATES... 

Catalyst I, containing the small tetrapropyl ammonium ion, was insoluble in the reaction medium during the epoxidation, so both the conversion and selectivity were low, only 60.6% and 60.2%, respectively. Catalyst A is a reaction-controlled phase-transfer catalyst with high catalytic activity and selectivity. Although catalyst 11 also has good catalytic performance, it was totally soluble in the reaction system during and after the epoxidation, because it contains a big octadecyl benzyl methyl ammonium ion. This makes catalyst recovery difficult. 

PO is an important chemical feedstock useful for producing polyurefhanes, resins, surfacfanfs, efc. This section presenfs resulfs on the epoxidation of propylene with a reaction-controlled phase-transfer cafalysf with in situ H2O2 and aqueous H2O2 as the oxidants. 

Recently, considerable effort has been expended on commercializing this technology. A new-generation reaction-controlled phase-transfer catalyst (catalyst D) was developed with lower production cost and a higher recovery yield (>95%) of the catalyst which makes it more economical. 

Since PO is water soluble, a few homogeneous catalytic systems employing aqueous H2O2 as oxidant have been reported [34]. This section report results on the homogeneous catalytic epoxidation of propylene to PO with 52% H2O2 using the reaction-controlled phase-transfer catalyst A [45]. The catalyst is easily... 

Cyclohexene oxide is an important intermediate used, for example, in synthesis of pesticides. A process for catalytic epoxidation of cyclohexene to cyclohexene oxide by reaction-controlled phase-transfer catalysis has been commercialized in China since 2003. It is an envirorunent-friendly process compared to the polluting traditional chlorohydrin method. 

M. Li, X. Jian, T. M. Han, L. Liu, Y. Shi, Reaction-controlled phase-transfer catalyst K3PV4024 for synthesis of phenol from benzene. Chin. J. Catal. 25 (2004) 681. 

M. Guo, Catalytic oxidation of cyclohexene to adipic acid with a reaction-controlled phase transfer catalyst. Chin. J. Catal. 24 (2003) 483. 

K. L. Li, N. Zhou, Z. W. Xi, Effects od solvents and quaternary ammonium ions in heteropoly-oxotungstates on reaction-controlled phase-transfer catalysis for cyclohexene epoxidatio. Chin. J. Catal 23 (2003) 125. 

Ishii, Y., Yamawaki, K., Ura, T., et al. (1988). Hydrogen Peroxide Oxidation Catalyzed by Heteropoly Acids Combined with Cetylpyridinium Chloride. Epoxidation of Olefins And Allylic Alcohols, Ketonization of Alcohols and Diols, and Oxidative Cleavage of 1,2-Diols and Olefins, J. Org. Chem., 53, pp. 3587-3593 Sato, K., Aoki, M., Ogawa, M., et al. (1997). A Halide-Free Method for Olefin Epoxidation with 30% Hydrogen Peroxide, Bull. Chem. Soc. Jpn., 70, pp. 905-915 Xi, Z. W., Zhou, N., Sun, Y., et al. (2001). Reaction-Controlled Phase-Transfer Catalysis for Propylene Epoxidation to Propylene Oxide, Science, 292, pp. 1139-1141 Neumann, R. 

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