钨杂多酸/膨润土的表面酸性和酯化催化活性  

Study on Surface Acidity of Bentonite Supported Tungstophosphorous Heteropoly Acid Catalyst and Catalytic Activity for Esterification

作　　者：林深[1] 余雅琴[1] 李小晶[1] 陈守正[1] 

机构地区：[1]福建师范大学化学系

出　　处：《福建师范大学学报（自然科学版）》1998年第4期43-46,共4页Journal of Fujian Normal University：Natural Science Edition

基　　金：福建省自然科学基金

摘　　要：以天然膨润土为原料，经净化、过筛、强酸处理和高温灼烧得活性白土，再用不同质量百分数的磷钨酸溶液，对活性白土进行负载得到磷钨酸／膨润土催化剂．以Ｈａｍｍｅｔ指示剂正丁胺滴定法测定催化剂表面酸强度及表面酸量按强度的分布，并与气固相催化合成甲酸乙酯的催化活性相关联，考察了催化剂的酸催化活性与表面酸性的关系．实验结果表明：制备的磷钨酸／膨润土催化剂表面酸强度分布在－１２．７０≤Ｈ０≤－８．２０、－１３．１６≤Ｈ０≤－１２．７０、－１３．７０≤Ｈ０≤－１３．１６、－１４．５２≤Ｈ０≤－１３．７０、Ｈ０≤－１４．５２范围内对酯化反应贡献分别为２．９２％、２４．１４％、８３．９１％、７．１０％、－１８．０６％．可见，影响酯化产率的主要因素是催化剂表面酸强度分布，不同酸强度的酸中心对催化酯化反应贡献不同．The catalyst was prepared by treating with the original bentonite and supporting tungstophosphorous heteropoly acid on it. The distribution of acid strength was determined by titrating with n butylamine,Hammett as indicator. It was related to the catalytic activity of synthesis of the ethyl formic ester under gas solid phase.The influence of the acid catalytic activity and the surface acidity was investigated.It showed that in the acid sites such as -12.70≤H 0≤-8 20,-13 16≤H 0≤-12 70, -13 70≤H 0≤-13 16,-14 52≤H 0≤-13 70 and H 0≤-14 52 made a contribution to the esterification with the ratioes of 2 92%,24 14%,83 91%,7 10% and -18 06% The main effection of the esterification yield was the distribution of acid strength on the surface.The acid centre of different acid strength has different contribution to the esterification.

关 键 词：表面酸性 酯化反应 催化活性 钨杂多酸 膨润土 

分 类 号：O643.361[理学—物理化学] O621.256.4[理学—化学]