氧化苯乙烯加氢体系中竞争反应的影响因素

Influential factors of competitive reaction in hydrogenation system of styreneoxide

以氧化苯乙烯为原料,通过催化加氢制得2-苯乙醇。考察了不同活性金属、活性金属负载量、载体及反应条件对氧化苯乙烯催化加氢存在的竞争反应的影响;选择Pd/Al_(2)O_(3)、Ni/Al_(2)O_(3)、Pt/Al_(2)O_(3)、Pd/MgO-Al_(2)O_(3)和Pd/AC(活性炭)催化体系为研究对象,采用XRD、H_(2)-TPD、BET、XPS和催化剂评价方法探究了催化剂与竞争反应的关联性。研究发现,在Pd基催化体系中,提高反应温度可以促进氧化苯乙烯加氢反应进行,但是过高温度更有利于异构化生成苯乙醛并进一步发生缩合反应。结果表明,以Pd_(0.5)/MgO-Al_(2)O_(3)(Pd含量为Al_(2)O_(3)载体质量的0.5%)为催化加氢体系,当反应温度为150℃时,氧化苯乙烯转化率为93%,2-苯乙醇选择性大于85%,而苯乙醛及其缩合物选择性小于15%。

2-Phenylethanol was prepared from styrene oxide by catalytic hydrogenation.The effects of different active metals,active metal loads,carriers and reaction conditions on the competitive reaction of catalytic hydrogenation of styrene oxide were investigated.Pd/Al_(2)O_(3),Ni/Al_(2)O_(3),Pt/Al_(2)O_(3),Pd/MgO-Al_(2)O_(3)and Pd/AC catalytic systems were used as the research objects.The correlation between catalysts and competitive reactions was explored was XRD,H_(2)-TPD,BET,XPS and catalytic evaluation method.The results showed that in Pd catalytic system,enhancing reaction temperature could promote the hydrogenation of styrene oxide,but excessive temperature was more favorable for isomerization into phenylacetaldehyde and further condensation reaction.It was found that when Pd_(0.5)/MgO-Al_(2)O_(3)(Pd content was 0.5%of the mass of Al_(2)O_(3)carrier)was used as catalyst and reaction temperature was 150℃,the conversion rate of styrene oxide was 93%,the selectivity of 2-phenylethanol was over 85%,and the selectivity of phenylacetaldehyde and its condensation products was less than 15%.