疏水性双功能坡缕石固体酸的制备及催化性能

Preparation of Hydrophobic Bifunctional Palygorskite Solid Acid and Its Catalytic Properties

3-巯丙基三甲氧基硅烷和4种不同碳数目硅烷修饰坡缕石,用双氧水氧化后得到疏水性双官能团介孔坡缕石固体酸。采用红外光谱、元素分析、X射线衍射、扫描电镜、NH3-TPD及N2吸附解析对其进行表征,以偏苯三酸三辛酯的合成作为探针反应对该固体酸的催化性能进行了研究。结果表明,随着疏水官能团烷烃链的引入,该固体酸的催化性能增强,催化剂用量下降。在反应温度为210℃,偏苯三酸酐2.4 g,酸醇摩尔比为1∶4.5,催化剂C16H33-PGS-SO3H为0.12 g(占总原料质量的1.23%),反应时间6 h的条件下,酯化率可达94.81%。

The hydrophobic bifunctional mesoporous of palygorskite solid acid was prepared by using H2O2 to oxidize the chemical palygoriskite which was pre-modified by grafting 3-mercaptopropyl trimethoxysilane and four kinds of silane coupling agent with different carbon number.The samples were characterized by means of IR,XRD,SEM,BET,NH3-TPD and elemental analysis.The catalytic activity of solid acid was tested for the esterification of trimellitic anhydride with 2-ethyl hexanol.The experimental results show that,with the introduction of hydrophobic hydrocarbon chain,the catalytic activity of palygorskite solid acid was increased and the amount of catalysts was decreased.The esterification yield was 94.81% under the following conditions：the molar ratio of trimellitic anhydride to 2-ethylhexyl alcohol was 1：4.5,the dosage of catalyst was 1.23% of total weight（0.12 g）,the reaction time was 6 h and the oil bath temperature was 210 ℃.