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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 natural bentonite is taken as raw material, and the activated clay is purified, sieved, treated with strong acid and burnt at high temperature, and the phosphatic tungstic acid / bentonite catalyst is loaded on the activated clay by using phosphotungstic acid solution with different mass percentages. Hammet indicator n-butylamine titration method was used to determine the acid strength and surface acidity of the catalyst by the intensity distribution, and with the solid-phase catalytic synthesis of ethyl formate catalytic activity were investigated catalyst acid catalytic activity and surface acidity relationship. The experimental results show that the surface acid strength distribution of the prepared phosphotungstic acid / bentonite catalyst is -12.70≤H0≤-8.20, -13.16≤H0≤-12.70, -13.70≤H0≤-13 .16, -14.52≤H0≤-13.70, and the contribution of H0≤-14.52 to esterification reaction were2.92%, 24.14%, 83.91%, 7.10% -18.06%. It can be seen that the main factor affecting the yield of esterification is the acid strength distribution on the catalyst surface. The acid centers with different acid intensities contribute to the catalytic esterification reaction differently.