基于羧酸改性TS-1分子筛的制备与环氧化性能研究

Preparation and Epoxidation Properties of TS-1 Molecular Sieve Modified by Carboxylic Acid

钛硅分子筛(TS-1分子筛)催化烯烃环氧化反应具有条件温和、环境友好等特点。以有机羧酸代替传统的无机酸TS-1分子筛的处理,有效降低了TS-1分子筛的非骨架钛含量。有机羧酸的酸性相对无机酸较弱,对骨架钛的损害较小。并且,TS-1分子筛在煅烧时,有机酸根会降解并逸出体系,不会形成额外的酸性位点。在3-氯丙烯环氧化反应中,三氯乙酸处理后的TS-1分子筛具有较高的环氧氯丙烷选择性和收率以及H2O2利用率。此外,三氯乙酸处理后的TS-1分子筛具有良好重复性能,以及更长的使用寿命。由此可见,三氯乙酸等有机酸可以有效替代盐酸等无机酸对TS-1分子筛进行处理。

The epoxidation of olefins catalyzed by TS-1 molecular sieve has the characteristics of mild conditions and environment-friendly.In this work,organic carboxylic acid was used to replace the traditional inorganic acid on handling TS-1 molecular sieve,which effectively reduced the non-framework titanium content.The acidity of organic carboxylic acid is weaker than that of inorganic acid,which does little damage to framework titanium.Moreover,when TS-1 molecular sieve is calcined,organic acid anions will degrade and escape from the system,and no additional acid sites will be formed.In the epoxidation of 3-chloropropene,TS-1 molecular sieve handled with trichloroacetic acid has high ECH selectivity,ECH yield and H2O2 utilization.In addition,TS-1 molecular sieve handled with trichloroacetic acid has good repeatability and longer service life.It can be seen that organic acids such as trifluoroacetic acid can effectively replace inorganic acids on handling TS-1 molecular sieve.