Cr_2O_3/SiO_2催化苯酚与碳酸二乙酯邻位烷基化反应  

Ortho-selective alkylation of phenol with diethyl carbonate over Cr_2O_3/SiO_2 catalyst

作　　者：贾泉[1] 薛冰[1] 许杰[1] 李永昕[1] 

机构地区：[1]常州大学石油化工学院,江苏常州213164

出　　处：《化工进展》2011年第5期1019-1023,共5页Chemical Industry and Engineering Progress

基　　金：江苏省高技术研究项目(BG2006015);江苏省"青蓝工程"青年骨干教师项目

摘　　要：以Cr(NO3)3?9H2O为前体,采用等体积浸渍法制备了一系列不同Cr2O3负载量的Cr2O3/SiO2催化剂;在固定床连续微反装置上,考察了Cr2O3/SiO2催化剂对苯酚与碳酸二乙酯邻位烷基化反应的催化性能;采用XRD、NH3-TPD、CO2-TPD和吡啶吸附、红外等手段对催化剂进行了表征。实验结果表明,随着Cr2O3负载量的增加,苯酚的转化率和邻乙基苯酚的选择性均逐渐增加;当Cr2O3负载量达到7.5%时,苯酚的转化率和邻乙基苯酚的选择性均达到最大值,分别为48%和67%。催化剂的表征结果表明,L酸中心是苯酚邻位烷基化反应的活性中心,苯酚转化率和邻乙基苯酚选择性的变化主要是由催化剂的酸、碱中心数目变化引起的。Cr2O3/SiO2 catalysts with different Cr2O3 loadings were prepared by impregnation with Cr（NO3）3？9H2O as precursor.Ortho-selective alkylation of phenol with diethyl carbonate was performed in a continuous flow fixed-bed reactor filled with Cr2O3/SiO2 catalysts.The Cr2O3/SiO2 catalysts were characterized by means of XRD,NH3-TPD,CO2-TPD and FT-IR with pyridine adsorption.The results indicated that with increasing Cr2O3 loading,conversion of phenol and selectivity to o-ethylphenol increased;when Cr2O3 loading reached 7.5%,conversion of phenol and selectivity for o-ethylphenol reached a maximum of 48% and 67%,respectively.The catalyst characterization results showed that the Lewis acid sites were the active centers of ortho-selective alkylation of phenol;and the variations in phenol conversion and selectivity to o-ethylphenol could be mainly ascribed to the change in the number of acid sites and base sites.

关 键 词：氧化铬/二氧化硅 碳酸二乙酯 苯酚 邻乙基苯酚 2 6-二乙基苯酚 

分 类 号：TQ243.1[化学工程—有机化工]