Abstract
Epoxidation of styrene with t-butyl hydroperoxide (TBHP) as an oxidizing agent has been conducted under liquid phase reaction conditions over Zr-Mn-MCM-41 with different n(Si)/(n(Zr) + n(Mn)) ratios and Mn-MCM-41(31) catalysts for selective synthesis of styrene oxide. The influences of various reaction parameters such as temperature, time, oxidants, and solvents, styrene to TBHP mmol ratios and acetonitrile (MeCN) to N,N-dimethylformamide (DMF) volume ratios on the conversion of styrene and the selectivity of styrene oxide have also been studied. With the decrease of the n(Si)/(n(Zr) + n(Mn)) ratios of Zr-Mn-MCM-41 catalysts from 327 to 49, the conversion of styrene as well as the yield and selectivity of styrene oxide increase due to the increase of the number of Lewis acid sites on the surface of catalysts. Moreover, the conversion and selectivity in Zr-Mn-MCM-41(49) is higher as compared to that of Mn-MCM-41(31). The Zr-Mn-MCM-41(49) is found to be reusable for the epoxidation of styrene with TBHP for selective synthesis of styrene oxide. (C) 2007 Elsevier Inc. All rights reserved.