固体碱催化剂KF/Al2O3催化合成乙二醇丁醚

摘要

针对乙二醇丁醚合成中传统催化剂产物后处理工艺复杂、污染环境等缺点,采用浸渍法制备KF/Al2O3负载型固体碱催化剂,催化环氧乙烷(EO)与丁醇反应合成乙二醇丁醚.考察了催化剂前驱体/载体比例、焙烧温度对催化性能的影响.结果表明氟化钾(KF)负载量为30%,焙烧温度为600℃时,催化剂时EO和丁醇反应催化活性最高.对催化剂进行了XRD表征,并采用Hammett指示剂法测定了催化剂的碱强度:pKa＞9.3的总碱量为3.0mmol/g催化剂,碱强度(H_)≥18.4,属中等碱强度催化剂.KF/Al2O3固体碱催化剂用于催化合成乙二醇丁醚最佳工艺条件为:反应温度110℃,反应压力0.20～0.30 MPa,催化剂用量为0.5%(m/m),n(BuOH)∶n(EO)为5∶1,反应时间100～120 min,EO转化率达99.47%.%In order to solve the problems that the traditional catalysts are dealt in difficult and polluted environments in ethylene glycol monobutyl ether production, the KF/Al2O3 solid base catalysts are prepared via impregnation method and their catalytic properties for the etherification to synthesize ethylene glycol monobutyl ether from ethylene oxide(EO) and butanol are evaluated.The influences of loading amount of KF over Al2O3 support, calcinate temperature of catalysts are examined.The results indicate that the catalyst possesses the best catalytic activity under the conditions of catalyst calcinate temperature 600 ℃ and 30％ of loading amount of KF.The catalysts are characterized by means of X-ray diffraction( XRD)and surface alkalinity are determined by Hammett indicator method.The results show that its base strength is higher than 18.4 and the base amount(pKa＞9.3)is 3.0 mmol/g Cat.The optimal etherification condition is as follows: reaction temperature 110℃, pressure O.20 ～0.30 MPa,reaction time 100 ～ 120 min,w(catalyst)= O.5％ and n(BuOH) :n( EO)= 5:1.Under such reaction conditions,the conversion of EO reaches 99.47％.