环氧丙烷的溶剂分解反应研究  

Study on Solvolysis of Propylene Oxide

作　　者：闫海生[1] 刘靖[1] 王祥生[1] 

机构地区：[1]大连理工大学碳资源综合利用开放实验室,大连116012

出　　处：《催化学报》2001年第3期250-254,共5页

基　　金：国家自然科学基金;中国石油化工集团公司资助项目!(2 9792 0 71)

摘　　要：考察了双氧水浓度、溶剂种类及添加的酸性或碱性物质等因素对环氧丙烷的溶剂分解反应的影响 .结果表明 :双氧水和TS 1沸石上的SiOH(硅羟基 )及TiO2 (锐钛矿 )对环氧丙烷的溶剂分解反应无催化活性 ;而TS 1中的骨架铝 ,沸石骨架中配位不饱和的Ti4 +形成的L酸中心 ,TS 1水解产生的钛羟基和由TS 1,双氧水及溶剂 (甲醇 )相互作用所生成的五元环中间活性钛等物种对环氧丙烷的溶剂分解反应具有催化活性 .原料中加入碱性物质可以显著抑制TS 1催化环氧丙烷的溶剂分解反应活性 ;添加酸性物质可以提高TS 1催化环氧丙烷的溶剂分解反应活性 .由于空间位阻效应 ,使得环氧丙烷的溶剂分解反应活性随着醇类溶剂分子的增大而降低 .在甲醇 水混合溶剂中 ,当水含量增加时 ,活性中间过渡物种的变化导致环氧丙烷的溶剂分解活性降低和双氧水分解率升高 .TS 1沸石晶粒大小对环氧丙烷的溶剂分解反应活性的影响显著 :大晶粒TS 1对环氧丙烷的溶剂分解反应的催化活性明显高于小晶粒TS 1.这是由于大晶粒TSEffects of hydrogen peroxide concentration, acid or base addition in the reactants, different solvents, etc. on solvolysis of propylene oxide in aqueous solution were studied. The results showed that hydrogen peroxide, silanol species and TiO2 did not have catalytic activity for solvolysis of propylene oxide, while framework Al, coordinatively unsaturated Ti4+ as Lewis acid site in the framework, Ti-OH and the five-membered ring active titanium species formed by TS-1, hydrogen peroxide and solvent can catalyze the solvolysis of propylene oxide. The solvolysis reactivity can be inhibited remarkably if a small amount of base was added in the medium, and the reactivity can be enhanced if acid was added. With the increase of alcohol ROH size, space steric effect made the solvolysis reactivity of propylene oxide decrease. In addition, the change of active species transition state made, solvolysis reactivity of propylene oxide decrease and the conversion of hydrogen peroxide increase when the water content in MeOH-H2O mixed solvent increased. The crystal size of TS-1 had significant effect on solvolysis of propyl-ene oxide. The larger crystal size of TS-1 had much higher catalytic activity for solvolysis of propylene oxide than the smaller crystal size of TS-1, on account of the longer internal diffusion distance in the former.

关 键 词：TS-1分子筛 环氧丙烷 溶剂分解反应 过氧化氢 酸性物质 碱性物质 丙烯 环氧化 催化活性 

分 类 号：O621[理学—有机化学]