磺酸树脂对柠檬醛环化的催化作用及其动力学特征研究

摘要

Cyclization of citral was catalyzed by D-72 sulfoacid resin.The influences of reaction medium,volume fraction of citral,dosage of catalyst,reaction temperature on conversion rate of citral and product selectivity were investigated.Kinetic characteristic of cyclization reaction was also studied.The results showed that cyclization products of citral are α-terpinene,p-cymene and 1-methyl-4-(1-methylethenyl)-benzene.Selectivity of cymene in carbon tetrachloride is 100 %.Conversion rate of citral using 0.8 g catalyst is 97.31 %.Using ethyl acetate as reaction medium,volume fraction of citral at 10 %,dosage of catalyst at 0.4 g and 343 K,conversion rate of citral and selectivity of cymene were 97.76 % and 67.8 %,respectively.Kinetic studies show that cyclization of citral catalyzed by D-72 sulfoacid resin follows the kinetics rule of pseudo-first-order reaction.Apparent activation energy calculated from least square method is 60.7 kJ/mol.%以D - 72磺酸树脂为催化剂催化柠檬醛环化反应,考查了反应介质、催化剂用量、反应温度和柠檬醛的体积分数对柠檬醛转化率和产物选择性的影响,探讨了环化反应的催化动力学特征.实验结果表明:环化反应产物为α - 松油烯、对伞花烃、对异丙烯基甲苯;用四氯化碳为反应介质,对伞花烃的选择性为100%;0.8g催化剂催化时柠檬醛的转化率为97.31%;用乙酸乙酯为反应介质,在柠檬醛体积分数为10%、催化剂0.4g、反应时间1h和343K条件下反应时,柠檬醛的转化率和对伞花烃的选择性分别为97.76%和67.8%.动力学研究表明,柠檬醛在D - 72催化剂上的环化反应服从一级动力学模型,经最小二乘法处理数据得表观活化能为60.7kJ/mol.