【作者】 李蒙召； 王译晨； 周丹红；

【Author】 Mengzhao Li;Yichen Wang;Danhong Zhou;College of Chemistry and Chemical Engineering,Liaoning Normal University;

【机构】 辽宁师范大学化学化工学院；

【摘要】 TS-1分子筛在H₂O₂水溶液中的一系列选择氧化反应均表现出优异的催化性能。本研究采用密度泛函理论计算的方法,以TS-1分子筛中Ti-η²-OOH和Ti-η¹-OOH模型为活性中心结构,探讨了H₂O、CH₃OH溶剂在Ti中心以及通过氢键作用的吸附,并进一步研究了氯丙烯的环氧化机理。结果表明,在不同活性中心结构上,氯丙烯环氧化反应的活化能垒依照下列顺序升高:Ti-η²-OOH-CH₃OH<Ti-η²-OOH<Ti-η²-OOH-H₂O<Ti-η¹-OOH（CH₃OH）<Ti-η¹-OOH（H₂O）,即三元环Ti-η²-OOH活性氧物种通过氢键作用与CH₃OH溶剂吸附后环氧化反应的活化能垒最低。对于五元环Ti-η¹-OOH活性中心,由于受到分子筛周围骨架空间障碍的影响,不利于溶剂分子的靠近,氯丙烯环氧化反应的活化能垒也相对较高。更多还原

【Abstract】 TS-1 molecular sieve have been attracting much attention,because it is capable of serving as highly efficient catalysts for the oxidation of various organic substrates with H₂O₂ as an oxidant under mild conditions.Density functional theory has been used to study the effects of solvent coordination on the structure and formation of the titanium hydroperoxo species believed to be the active intermediate of epoxidation reactions in TS-1/H₂O₂ catalytic systems and allyl chloride.It indicated that the most likely reaction activation energy is Ti-η²-OOH species with adsorption of CH₃OH by hydrogen bonding.For the Ti-η¹-OOH activity center,due to steric hindrance is not conducive to solvent molecules close that allyl chloride epoxidation reaction activation energy barrier is high,respectively.更多还原