The paper mainly discusses the effects of solvents on reaction-controlled phase-transfer catalysis which possesses the advantages of both homogeneous and heterogeneous catalysis. The reaction-controlled phase-transfer catalysis system not only realizes the catalyst recovery from the product over homogeneous catalysis but also avoids the low reaction rate, long reaction time, leaching of the active species and low selectivity in heterogeneous catalysis. For a reaction-controlled phase-transfer catalyt,its characteristic is affected not only by its composition including anion and cation but also by the used solvent during the reaction. A suitable solvent can increase the conversion rate of the substrate and the yield of product, and benefits the recovery of the catalyst. The effects of solvents on reaction-controlled phase-transfer catalysis systems including epoxidation of olefins, oxidation of alcohols to prepare aldehydes or ketones, esterification, oxidative cleavage of olefins or alcohols to prepare dicarboxylic acid, acetalation, oxidative desulfurization, hydroxylation reaction and catalytic reduction by Se, are presented in this paper. Finally, some possible measures to overcome the shortcomings in the present catalytic system are put forward and the future research prospects are discussed.
Contents
1 Introduction
2 Principle of the reaction-controlled phase-transfer catalysis
3 Effects of solvents on reaction-controlled phase-transfer catalysis
3.1 Epoxidation of olefins
3.2 Oxidation of alcohols to prepare aldehydes or ketones
3.3 Esterification
3.4 Oxidative cleavage of olefins or alcohols to prepare dicarboxylic acid
3.5 Acetalation
3.6 Oxidative desulfurization
3.7 Hydroxylation reaction
3.8 Catalytic reduction by Se
4 Conclusion and outlook