磷钨酸掺杂聚苯胺催化合成正己酸正丁酯及其动力学研究

Synthesis and kinetics of butyl hexanoate catalyzed by H_3PW_(12)O_(40)/PANI

以磷钨酸掺杂聚苯胺(H3PW12O40/PANI)为催化剂,正己酸和正丁醇为原料合成正己酸正丁酯。考察了醇酸摩尔比、催化剂用量、反应时间等因素对反应转化率的影响,以及催化剂的重复使用性能,并测定了动力学数据。结果表明较佳反应条件为:n(正丁醇)∶n(正己酸)=4∶1,H3PW12O40/PANI的用量为正丁醇和正己酸总质量的8%,在温度不高于126℃条件下反应5 h。较佳反应条件下正己酸的转化率为98.88%;在此条件下进行重现,转化率稳定在98.46%以上;催化剂使用4次后,正己酸的转化率为97.97%。反应总级数为二级,表观活化能为21.87 kJ·mol-1,指前因子为1.636 L·mol-1·min-1。

Synthesis of butyl hexanoate from hexanoic acid and n - butanol on H3 PW12 O40/PANI was studied. Effects of reaction conditions,such as molar ratio of n- butanol to hexanoic acid, catalyst dosage and reaction time as well as the reusability of the catalyst were investigated. The kinetic data of this system were measured in a batch reactor. The optimum reaction conditions were obtained as ： n （ n - butanol） ： n （ henanoic acid ） = 4：1 ;H3PW12O40/PANI dosage,8% of the total mass of n- butanol and hexanoic acid;reaction time,5 h at temperature less than 126 ℃. The results showed that conversion of hexanoic acid can reach 98. 88% ;the conversion rate in the repeated operation remains above 98. 46% ; activity of the catalyst remains at 97. 97% conversion after reuse of 4 times. The synthesis of butyl hexanoate is a second -order reaction on H3PW1204o/PANI. The apparent activation energy is 21.87 kJ · mol^-1 ,and the pre - exponential factor is 1. 636 L · mol^-1 · min^-1.