溶胶-凝胶法制备SiO_2固载酸性离子液体催化剂及其在2-甲基-4-甲氧基苯胺“一锅法”合成中的应用

Preparation of SiO_2 immobilized acidic ionic liquid catalyst by sol-gel method and its application in one-pot synthesis of 2-methyl-4-methoxyaniline

采用溶胶-凝胶法制备了SiO2固载的酸性离子液体N-甲基咪唑丙磺酸硫酸氢盐([HSO3-pmim][HSO4])催化剂,运用FT-IR,TG-DTG和SEM等技术对催化剂进行了表征.考察了制备过程中盐酸用量和正硅酸乙酯(TEOS)用量对[HSO3-pmim][HSO4]固载牢度的影响,将其与Pt/C组成双功能催化体系用于邻硝基甲苯加氢重排"一锅法"合成2-甲基-4-甲氧基苯胺(MMA)反应中.研究结果表明:在反应温度50℃、氢压0.04MPa条件下反应6h,邻硝基甲苯转化率为100%,MMA的选择性为45.23%,催化剂循环使用三次后仍有较高的选择性.

SiO2immobilized acidic ionic liquid [HSO3-pmim][-HSO4 ] catalyst was prepared using sol-gel method. The catalyst was characterized by FT-IR, TG-DTG and SEM techniques. The effects of the amount of hydrochloric acid and TEOS on the supporting intension of [HSO3-pmim][HSO4] were investigated. [HSO3-pmim][HSO4]/SiO2 with 3%Pt/C was used in the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol to 2-methyl-4- methoxyaniline by a one-pot method. The results showed that the conversion of o-nitrotoluene was 100% and the selectivity to MMA was 45.23% over the catalyst system under the conditions of the temperature 50 ℃ and hydrogen pressure 0.04 MPa. After reused 3 times, the catalyst system still showed good selectivity to MMA.