SiO2气凝胶负载无水四氯化锡催化顺酐与正丁醇酯化反应的研究

通过表面反应制备了气凝胶SiO2负载无水四氯化锡催化剂并应用于顺酐与正丁醇的酯化反应.结果表明,酯化产物主要为马来酸二丁酯(DBM)与富马酸二丁酯(DBF),其优化条件为:载体SiO2气凝胶焙烧温度500℃,物料摩尔比顺酐∶正丁醇:催化剂=1∶2∶0.0028,反应时间6 h.并且通过XRD,FTIR,DRUV-vis,N2物理吸附以及元素分析技术对所合成催化剂进行表征.结果表明:无水四氯化锡成功负载于SiO2气凝胶表面,在催化酯化反应当中实现了86.1%的顺酐转化率,此结果接近于国内外所报道的均相体系成果,同时在催化回收利用六次后,其活性虽逐步下降,但仍是空白的2倍.分析测试表明,反应过程中Cl的流失量较大、反应物及产物在催化剂表面产生了吸附,这些可能是导致催化活性下降的主要原因.

Esterification of Maleic Anhydride with Butanol over Tin Tetrachloride Supported on Silica Aerogels Catalyst

Dibutyl maleate(DBM) and dibutyl fumarate(DBF) are important intermediates extensively used in industrial application.The current paper reports a study on the efficacy of tin tetrachloride supported on silica aerogels catalyst(Sn/Si) in the esterification of maleic anhydride(MA) with butanol(BO) at reflux in which DBM and DBF are synthesized directly.The catalyst was characterized by X-ray powder diffraction(XRD),Infrared(FTIR) spectra,UV-vis diffuse reflectance spectra(DRUV-vis),N2 sorption and element analysis.The optimal reaction conditions were confirmed as follows: calcination temperature of silica aerogels was 500 ℃,reaction time was 6 h,mol ratio of reactants was 1∶ 2∶ 0.0028(MA∶ BO∶ Sn/Si).The conversion of MA was up to 86.1%,and the selectivity to DBM and DBF were 68.3% and 1.84% respectively,which almost same as the homogeneous catalyst system.And the Sn/Si catalyst kept a reasonable activity after 6 times reused cycles.The lost of Cl and the reaction of MA,BO,DBM,DBF with the catalyst surface could result in the decrease of the catalytic activity.