HYDROPHOBIC HYDROPHILIC EFFECTS ON THE TITANIUM(IV)-CATALYZED EPOXIDATION OF CYCLOHEXENE BY TERT-ALKYL HYDROPEROXIDES - 2-METHYL-1-PHENYL-2-PROPYL HYDROPEROXIDE (MPPH) VERSUS TERT-BUTYL HYDROPEROXIDE (TBHP)/

The epoxidation of cyclohexene in acetonitrile under argon at room tem perature on a titanium(IV)-containing MCM41 silica catalyst is faster and gives a greater final yield of cyclohexene oxide when the oxygen a tom donor is 2-methyl-1-phenyl-2-propyl hydroperoxide (MPPH) than when it is tert-butyl hydroperoxide. This is shown to be due to stronger r etardation of the oxidation by tert-butyl alcohol (TBA) than by the al cohol derived from MPPH. The difference in retardation between these t wo alcohols is attributed to the greater hydrophilicity of TBA. Aceton itrile is a better solvent for this reaction than isooctane, pyridine and a variety of alcohols. These solvent effects are attributed to the hydrophilic nature of the catalyst.