聚苯乙烯负载酸性离子液体催化剂的制备及催化性能

以聚乙烯吡咯烷酮为分散剂、偶氮二异丁腈为引发剂、乙醇为分散介质,通过苯乙烯与酸性离子液体1-(3-磺酸基)丙基-3-乙烯基咪唑硫酸氢盐((CH2)3SO3HVIm]HSO4])的分散聚合,制备了聚苯乙烯(PS)负载酸性离子液体催化剂(PS-(CH2)3SO3HVIm]HSO4]),用FTIR、TG-DSC和元素分析方法对其进行了表征。表征结果显示,酸性离子液体较好地负载在PS表面,负载量为0.892 9mmol/g,该催化剂具有良好的热稳定性。将该催化剂用于醋酸与正丁醇的酯化反应,反应体系呈均相,反应结束后加入乙醇,体系转变为非均相,这种现象可使反应高效进行且催化剂易于回收。在较佳的反应条件(反应温度92℃、m(催化剂)∶m(总反应物)=0.080、n(正丁醇)∶n(醋酸)=1.2∶1、反应时间3h、环己烷8mL)下,醋酸正丁酯的收率可达到97.8%;催化剂重复使用4次后醋酸正丁酯的收率为80.2%。

Preparation and Performance of Polystyrene Supported Acidic Ionic Liquid Catalyst

Polystyrene supported 1-(3-sulfonic group) propyl-3-vinyl imidazolium hydrosulfate acidic ionic liquid(PS-(CH_2)_3SO_3HVIm]HSO_4]) catalyst was prepared through dispersion polymerization in Absolute alcohol as disperse medium with polyvinylpyrrolidone as dispersion agent and 2,2′-azobisisobutyronitrile as initiator.The catalyst was characterized by means of FTIR,TG-DSC and element analysis.Results showed that the acidic ionic liquid was supported on the polystyrene support and thermal stability of the catalyst with loading 0.892 9 mmol/g was good.The catalyst was used in the synthesis of n-butyl acetate by esterification of n-butyl alcohol and acetic acid.The catalytic system possessed characteristic of phase-transfer reaction from homogeneous phase to heterogeneous phase with addition of ethanol,so the product yield was high and the catalyst could be separated easily.Under the optimized reaction conditions of reaction temperature 92 ℃,n(n-butyl acetate)∶n(acetate acid)(1.2∶1,) m(PS-(CH_2)_3SO_3HVIm]HSO_4])∶m(reactants)0.080 and reaction time 3 h,cyclohexane 8 mL,yield of n-butyl acetate could reach 97.8%.After the catalyst was reused four times,yield of n-butyl acetate still achieved 80.2%.