胺丙基官能化SiO_2的制备及其催化性能

Preparation and Catalytic Activity of Amine Functionalized Silica

应用超声波技术在温和条件下以3-胺丙基三甲氧基硅烷为偶联剂制得了不同嫁接量的胺丙基官能化SiO2;考察了3-胺丙基三甲氧基硅烷用量和超声波处理时间对胺丙基嫁接量的影响;对所制备的试样进行了傅里叶变换红外光谱、元素分析、29Si核磁共振和热重分析表征;将试样用于催化苯甲醛与氰乙酸乙酯的Knoevenagel缩合反应和苯酚与碳酸二甲酯的甲基化反应测试其催化性能。实验结果表明,胺丙基以共价键嫁接到SiO2载体上;当3-胺丙基三甲氧基硅烷用量5.0mL、超声波处理时间2h时,胺丙基嫁接量最大(2.00mmol/g);胺丙基官能化SiO2在Knoevenagel缩合反应及甲基化反应中反应物的转化率均大于95%,产物选择性为100%;胺丙基官能化SiO在Knoevenagel缩合反应中的稳定性优于甲基化反应。

Amine functionalized silica, using 3-aminepropyltrimethoxysilane （APTMS）as couphng agent, was prepared by ultrasonic technique. Effects of coupling agent dosage and ultrasonic treating time on quantity of grafted organic groups were studied. The prepared samples were characterized by means of PTIR, element analysis,^29 Si NMR and TG. The quantity of grafted organic groups was influenced by amount of coupling agent and ultrasonic treating time. Knoevenagel reaction between benzaldehyde and ethyl cyanoacetate ,and methylation between phenol and dimethyl carbonate（DMC） on prepared amine functionalized silica catalyst were investigated. The catalyst exhibited promising catalytic property and could be reused in both reactions again. Conversions of both benzaldehyde and phenol are more than 95% and selectivities of relevant products are 100%. The prepared catalyst shows better reusability in Knoevenagel reaction than in methylation.