稀土盐酯化催化剂失活原因的探讨

实验发现，稀土盐作为酯化反应催化剂，重复使用时活性有较大幅度的下降。本文采用Ｘ射线衍射（ＸＲＤ）及程度升温分解（ＴＰＤＥ）等手段，结合四水硫酸铈（Ⅳ）催化合成乙醇单乙醚醋酸酯的反应活性测定，对鹇催化剂和经不同预处理的催化剂进行了研究，讨论了催化剂失活的原因。结果表明，四水硫酸铈（Ⅳ）的催化活性与表面质子酸性质有关。在反应过程中，催化剂发生结晶水的丢失，铈离子价态的降低及晶体结构的变化，使催化剂的质

DEACTIVATION OF RARE-EARTH SALT CATALYST FOR ESTERIFICATION OF 2-ETHOXY ETHANOL WITH ACETIC ACID

he catalytic activity of rare-earth salt used as the catalyst for esterification reduced to a great extent when rare-earth salt was used repeatedly. In this paper, fresh and pretreated Ce(SO4)2. 4H2O2 used forthe esterification of 2-ethoxy ethanol with acetic acid were studied by Xray diffraction (XRD) and temperature programmed decomposition(TPDE). The causes for the deactivation of catalyst were discussed. Itwas found that the catalytic activity of Ce(SO4)2. 4H2O2 catalyst resulted from the sites of Bronsted acid. In the process of reaction, theamount of Bronsted acid decreased and its intensity became weaker because of the loss of crystal water, the reduction of Ce4+ and the variation of crystal structure, so the catalytic activity of catalyst decreased.