固体杂多酸盐催化性能的研究Ⅱ．磷钨、硅钨杂多酸的合成、表征和在叔丁醇脱水反应中的催化性能

STUDY ON CATALYTIC BEHAVIOUR OF SALTS OF HETEROPOLY ACIDS Ⅱ.SYTHESIS,CHARACTERIZATION AND CATALYTIC ACTIVITY IN DEHYDRATION OF Cs SALTS OF PW 12 AND SiW 12 HETEROPOLY ACIDS

合成了Ｈ３－ｘＣｓｘＰＷ（ｘ＝０～３），Ｈ４－ｘＣｓｘＳｉＷ（ｘ＝０～４）两系列杂多酸铯盐，以Ｈａｍｍｅｔ指示剂法及ＮＨ３－ＴＰＤ研究了它们的酸性质，用ＢＥＴ法测定了其表面积，并在叔丁醇脱水生成异丁烯的反应中考察了杂多酸铯盐的催化性能，其催化活性高于文献报导的其它杂多化合物在相同条件下的活性，并对该反应作了动力学分析，求得了有关参数，发现杂多酸铯盐的催化活性仅与它们的酸性质有关，与表面积无关，属于拟液相反应。

A Series of Cs +salts of heteropoly acids(HPW 12 ,HSiW 12 ) were synthesized.The Hammett function H 0 was determined in order to investigate the acidic strength,their acidic contents being measured by NH 3 TPD.Their specific surface areas were determined by BET method.The acid catalytic activity of various salts was investigated in the dehydration of t butyl alcohol as a test reaction,their kinetics of the reaction also being studied.It was confirmed that, the acid contents in the bulk rather than on the surface responsible for the catalytic activity,the reaction seems to take place in the pseudoliquid phase.