摘要
用低温沉淀和低温陈化的方法,制备了以氧化锆和氧化钛为主要组分并用镧系过渡金属氧化物改性的无机固体超强酸催化剂,测定了催化剂的酸强度、酸量和硫含量,用红外光谱法推测了其表面结构,研究了该催化剂对难以进行水分分离的乙酸乙酯合成过程的催化作用和工艺条件。结果表明:以反应-精馏耦合反应装置合成乙酸乙酯的最佳工艺条件为醇酸摩尔比为2:1,催化剂用量为3%(wt),反应时间为5.5h。催化剂的有效酸量比未改性的催化剂增加,耐水性和催化活性明显改善,反应后硫损失量减少。由红外光谱图可知催化剂中SO42-以桥式双配位与氧化物相结合,有L、B两种酸性中心,其中以B酸位为主。
Sulfated zirconia-titania oxide solid super acid catalysts modified by lanthanum oxide were prepared and aged at low temperature （0℃）, and were used for the synthesis of ethyl acetate. The catalytic activity was measured by the ester yield obtained from the reaction of acetic acid with ethyl alcohol. The acid strength of the catalysts prepared was tested by Hammett indicators, the sulphur content in the catalyst was analyzed by BaSO4 gravimetric method and the catalyst structure was determined by IR. The results show that： （1） the catalyst molecular structure is bridge biden-tate, L and B acid sites are in existence on the catalyst surface; （2） the optimum reaction conditions are as follows： the molar ratio of C2H5OH to CH3COOH is 2 ： 1, reaction time is 5.5 h, the catalyst amount used is 3%（wt） and adding time of acetic acid is 3.5 h; （3） the ester yield can keep more than 77% after the catalyst was reused for 5 times; （4） the sulphur lost of the La modified catalyst during the esterification reaction is less than that of the catalyst without modified by La. For the esterification, the reaction-distillation coincident technique was employed in this study.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2008年第1期60-64,共5页
Journal of Chemical Engineering of Chinese Universities
关键词
固体超强酸
复合催化剂
乙酸乙酯合成
结构表征
solid superacid
composite catalyst
esterification
structural characterization
作者简介
崔波（1945-），女，山东莱阳人，青岛科技大学教授，学士。通讯联系人：崔波，E-mail：cuibochem@qust．edu．cn
