疏水性双功能坡缕石固体酸的制备及催化性能研究

Preparation of hydrophobic bifunctional palygorskite solid acid and its catalytic properties

摘要:

3-巯丙基三甲氧基硅烷和四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 ℃时，偏苯三酸酐2.4 g，酸醇摩尔比为1:4.5，催化剂C 16H33-PGS-SO3H为0.12 g (总原料质量的1.2%)，反应6 h，酯化率可达94.81%。

Abstract:

The hydrophobic bifunctional mesoporous of palygorskite solid acid was prepared by using H2O2 to oxidize the chemical palygoriskite, which is modified by grafting 3- mercaptopropyl trimethoxysilane and four kinds of silane coupling agent different carbon number. The samples were characterized by IR, XRD, SEM, BET, NH3-TPDand elemental analysis. The catalytic activity of solid acid was tested for the esterification of trimellitic anhydride with 2-ethyl hexanol. The experimental results showed that the catalytic activity of palygorskite solid acid was increased and amount of catalysts was decrased by hydrophobic hydrocarbon chain leading into. The esterification yield is 94.81% under the conditions： the molar ratio of trimellitic anhydride to 2-ethylhexyl alcohol is 1:4.5, the weight of catalyst is 1.2％ of total weight(0.12 g), the reaction time is 6 h and the oil bath temperature is at 210℃．