A novel manganese tungstate nanorod catalyst for the oxidation of styrene with tert-butyl hydroperoxide as oxidant  

作　　者：Shanmugam Manimaran Arumugam Pandurangan Gopalakrishnan Govindasamy 

机构地区：[1]Department of Chemistry,Anna University,Chennai,Tamil Nadu,600025,India [2]Energy Cluster,School of Engineering,University of Petroleum and Energy Studies(UPES),Dehradun,Uttarakhand,248007,India

出　　处：《Tungsten》2024年第4期845-858,共14页钨科技（英文）

基　　金：the Anna Centenary Research Fellowship(CFR/ACRF/2016/39)funded by Anna University,Chennai to carry out this work;the Department of Science&Technology-Fund for Improvement of S&T Infrastructure(DST-FIST)sponsored Department of Chemistry。

摘　　要：Catalyst,solvent and process parameters are the keys for the selective oxidation of styrene and other olefins to value added intermediates.Hence MnWO_(4)was synthesized by the one-pot hydrothermal method using Pluronic F127 as a surfactant,characterized and evaluated for the oxidation of styrene and different olefins,using tert-butyl hydroperoxide(TBHP)as oxidant.X-ray diffractogram confirmed the phase purity of MnWO_(4)which became further evident from the near surface equimolar proposition of Mn and W in+2 and+6 oxidation states,respectively,as inferred from X-ray photoelectron spectra.N_(2)sorption followed typeⅣa isotherm with H_(3)hysteresis loop,starting at the relative pressure(P/P_(o))of 0.9,typically of mesoporous materials containing macropores as further confirmed by pore-size distribution.Transmission electron microscope images of MnWO_(4)revealed its nanorod morphology.In the absence of catalyst,styrene conversion was 35%with benzaldehyde as the sole product and addition of 75 g of MnWO_(4)increased the styrene conversion to 97.3%,and the styrene oxide selectivity from 0%to 85%demonstrated its activity and selectivity.For the maximum conversion and styrene oxide selectivity optimum temperature,styrene:TBHP molar ratio,catalyst amount and solvent were found to be 70℃,1:2,75 mg,and acetonitrile,respectively.MnWO_(4)catalyst retained its activity and selectivity for five recycles,confirming its recoverability and reusability.From the kinetic studies,pre-exponential factor and apparent activation energy were found to be 0.206 s^(-1)and 31.5 kJ·mol^(-1),respectively,and a reaction mechanism was proposed.MnWO_(4)catalyst was active for oxidation of alkenes,cycloolefins and alkenyl aromatics with high selectivity for epoxides.

关 键 词：Manganese tungstate nanorod Styrene oxidation EPOXIDATION 

分 类 号：TQ426[化学工程] TB383.1[一般工业技术—材料科学与工程]