Pt-[HSO_3-bvim]HSO_4/SiO_2双功能催化剂制备及其催化性能研究

Preparation and Catalytic Performance of Bi-Functional Catalyst Pt-[HSO_3-bvim]HSO_4/SiO_2

针对离子液体固载中存在的使用物理方法固载的离子液体易流失的问题,采用化学键合的方法将离子液体固载于硅胶表面。合成了一种新型Brφnsted酸性离子液体1-乙烯基-3-磺丁基咪唑硫酸氢盐([HSO3-bvim]HSO4),并通过自由基链转移反应将该酸性离子液体用化学键固定于氢硫基官能团化的硅胶表面,制备出了[HSO3-bvim]HSO4/SiO2固体酸催化剂,再利用化学还原方法在该固体酸催化剂上负载金属铂,得到Pt-[HSO3-bvim]HSO4/SiO2双功能催化剂。采用傅立叶红外光谱、核磁共振光谱、热重、元素分析和X射线衍射等方法对所制备的样品进行了结构表征。将该双功能催化剂应用于硝基苯催化加氢合成对氨基苯酚反应中,结果表明,其具有一定的催化活性。在85℃、4h、0.4MPa条件下,双功能催化剂可以多次重复使用,对氨基苯酚的收率大于3.1%。

In order to solve the problem of ionic liquid leaking from its support, a chemical method was used to immobilize the ionic liquid on silica gel via covalent bond. A novel Bronsted type acidic ionic liquid 1-vinyl-3-sulfobutyl imidazolium hydrogen sulfate, [HSO3-bvim]HSO4, was synthesized. Then via free radical chain transfer reaction, the [HSO3-bvim]HSO4 prepared was immobilized on silica gel functionalized by sulphydryl to obtain [HSO3-bvim]HSO4/SiO2 solid acid catalyst. Finally, the metallic Pt was loaded on the prepared solid acid catalyst by the chemical reduction method to obtain the bi-function catalyst Pt-[HSO3-bvim]HSO4/SiO2. The samples of prepared bi-function catalyst were characterized by FT-IR, NMR, TG, elemental analysis and XRD, respectively. The hydrogenation of nitrobenzene to p-aminophenol （PAP） was used to evaluate the bi-function catalyst, and the results show that the PAP yield is higher than 3.1% under following conditions： hydrogenation temperature of 85℃, reaction time of 4 h and H2 pressure of 0.4 MPa. And the bi-function catalyst can be reused for several times.