摘要
研制SO42-改性的锆交联蒙脱土(SO42-/Zr-CLM)固体酸催化剂,采用IR、Py-TPD和Py-IR等方法研究其表面酸中心的结构特征,并以柠檬酸和正丁醇的酯化反应为探针反应,研究其表面酸中心与催化活性的关系.实验结果表明:SO42-/Zr-CLM表面同时具有Bronsted(B)酸和Lewis(L)酸,L酸为弱酸中心,B酸为强酸中心;B酸中心是主要催化活性中心;催化剂经过500℃焙烧后,B酸的酸量显著增加,这可能是由于Zr与SO42-形成了螯合状配位结构,有利于形成更多的B酸中心并且提高其酸强度.
The zirconium cross-linking montmorillonite solid acid modified by SO4^2- （SO4^2-/Zr-CLM） was prepared. The structure features of its surface acid sites were analyzed by means of IR, Py-TPD and Py-IR. The relationship between its surface acid sites and catalytic activity was also analyzed by using the esterification of citric acid with nbutanol as the probe reaction. The results show that both Bronsted（B） acid sites and Lewis （L） acid sites co-exist on the surface of the catalyst SO4^2-/Zr-CLM, on which the L acid sites are basically weak acid sites while B acid sites are strong. The B acid sites are the main sites for catalytic activity. The amount of B acid sites is increased significantly after calcinated at 500 ℃, which is probably due to the formation of the chelate ligand structure formed by SO4^2- and zirconium, which is in favor of the formation of B acid sites and increases its acidic intensity.
出处
《汕头大学学报（自然科学版）》
2008年第2期43-49,共7页
Journal of Shantou University：Natural Science Edition
基金
广东省科技计划资助项目(No:2006B36702003)
关键词
SO4^2-改性锫交联蒙脱土
固体酸
表面酸中心
催化活性
酯化反应
zirconium cross-linking montmorillonite modified by SO4^2-
solid acid
surface acid sites
catalytic activity
esterification
