酸掺杂聚苯胺催化马来酸丁酯化及动力学

Synthesis and kinetics of dibutyl maleate by polyaniline doped with p-toluene sulfonic acid as catalyst

用对甲苯磺酸作为搀杂剂对水相氧化法合成的盐酸搀杂的聚苯胺(HC l/PANI)进行搀杂,制备了由聚苯胺(PANI)负载对甲苯磺酸的固体酸催化剂(PTSA/PANI)。以PTSA/PANI为催化剂、马来酸酐和正丁醇为原料合成马来酸二丁酯。考察了原料配比、催化剂用量和反应时间等因素对反应的影响以及催化剂的重复使用性能,测定了反应动力学。最佳反应工艺条件为:n(正丁醇)∶n(马来酸酐)=3.33∶1、w(PTSA/PANI)=3.81%、反应温度≤130℃、反应时间3 h。结果表明,在该条件下马来酸酐的转化率为96.23%;催化剂经重复使用5次后,马来酸酐的转化率为90.82%;确定反应级数为二级,表观活化能为41.0 kJ/mol。对甲苯磺酸搀杂聚苯胺催化剂具有催化活性高、稳定性好、容易制备、无环境污染等优点。

HCl doped-polyaniline （HCl/PANI） was prepared by aqueous phase oxidation polymerization process. A new solid acid catalyst （PTSA/PANI） was prepared by doping HCl/PANI with p-toluene sulfonic acid as dopant. Synthesis of dibutyl maleate from maleic anhydride and n-butyl alcohol on PTSA/PANI was studied. Effects of reaction conditions, such as mole ratio of n-butyl alcohol to maleic anhydride, catalyst content, and reaction time as well as the reusability of the catalyst were investigated. The kinetics such as the rate constant of various reaction temperatures, reaction order and apparent activation energy, etc. was measured. The optimum reaction conditions were obtained： n （n-butyl alcohol） ： n （maleic anhydride） = 3.33 ： 1, w （PTSA/PANI） = 3.81%, reaction temperature ≤130 ℃, reaction time 3 h. The results show that conversion of maleic anhydride can reach 96.23%, and activity of catalyst is still kept at 90. 82% after being used 5 times, and the synthesis of dibutyl maleate is a second-order reaction on PTSA/PANI catalyst, and the apparent activation energy of 41.0 kJ/mol for PTSA/PANI catalyst was obtained. PTSA/PANI has many advantages, such as high activity, good stability, easy preparation and pollution-free to the enviromnent.