无机-有机杂化材料催化合成乙酸异戊酯及动力学研究

以甘氨酸(Gly)和磷钨酸为原料合成的一系列无机有机杂化材料为催化剂,考察各因素对其催化合成乙酸异戊酯的影响,并利用响应面分析法优化乙酸异戊酯合成工艺。研究表明,[GlyH]_(1.0)-H_(2.0)PW_(12)O_(40)催化剂具有最高的催化酯化反应活性和重复使用性能。响应面分析法优化乙酸异戊酯合成的最佳条件为:醇酸摩尔数比为1.05∶1,催化剂用量为酸质量的4.5%,反应时间2.0h,带水剂量10mL,该条件下,乙酸异戊酯产率为98.5%,结果与模型预测值基本相符。优化条件下[GlyH]_(1.0)-H_(2.0)PW_(12)O_(40)催化酯化反应表观活化能为79.73kJ/mol。

Catalytic synthesis of isoamyl acetate by amino acid functional heteropolyacid as catalysts and its kinetics

The organic-inorganic hybrid catalyst,namely[GlyH]_xH_3-xPW₁₂O₄₀(x=1.0-3.0),was prepared by combining phosphotungstic acid and glycine (Gly).The effects of various factors on the catalytic synthesis of isoamyl acetate with using[GlyH]_xH_3-xPW₁₂O₄₀(x=1.0-3.0) as catalysts were studied,and the synthesis process of isoamyl acetate was optimized by response surface methodology (RSM).The results show that[GlyH]_1.0-H_2.0PW₁₂O₄₀ catalyst has the highest catalytic esterification reactivity and reusability.The optimum conditions are n(isoamylol):n(acetic acid)=1.05:1,the amount of catalyst to acetic acid 4.5%,reaction time 2.0 h and water-carrying agent 10 mL.Under these conditions,the yield of isoamyl acetate reaches 98.5%,which is in basic agreement with values predicted by the mathematical model.Under the optimal conditions,the active energy of the esterification is 79.73 kJ/mol.