丙烯酸十八酯制备方法研究

Evaluation on the Preparations of Octadecyl Acrylate

采用两种酯化方法制备了丙烯酸十八酯 ,研究了影响酯化反应的因素。用甲苯作携水剂的溶剂酯化方法的适宜工艺为丙烯酸与十八醇摩尔比 1 .2∶ 1 .0 ,对甲苯磺酸 3 .0 % (质量分数 ) ,对苯二酚 1 .0 % (质量分数 ) ,在 1 1 0～ 1 2 0°C回流反应 8h,高级酯产率 90 %以上。不使用携水剂的熔融酯化法的适宜工艺为 :丙烯酸 /十八醇摩尔比 1 .2∶ 1 .0 ,对甲苯磺酸 1 .0 % (质量分数 ) ,对苯二酚0 .5 % (质量分数 ) ,回流条件下逐步升温反应 6 h,高级酯产率 90 %以上。系统比较了两种方法制备的丙烯酸十八酯的熔点、沸点和元素组成 ,用红外光谱和核磁共振谱对比分析并证实其结构特征无明显差异 ,表明用熔融酯化法制备丙烯酸十八酯既可减少催化剂和阻聚剂的用量 ,又能保证以较高产率获得较纯的丙烯酸高级酯 ,是一种高效、可靠地制备该类单体的先进方法。

The factors effecting the melt direct esterification and normal solvent direct esterification of acrylic acid and octadecyl alcohol were investigated. The optimum preparation conditions for melt direct esterification were: molar of acrylic acid to octadecyl alcohol 1.2, 3.0% toluene p sulfonic acid as catalyst, 1.0%, hydroqninone as inhibitor and reflux at 110～120 °C for 8 h and the yield was more than 90%. The optimum preparation conditions for solvent direct esterification were: molar ratio of acrylic acid to octadecyl alcohol 1.2, 1.0% toluene p sulfonic acid 1.0%, 0.5% hydroqninone and reacting 6 h, and the yield was also 90% or more. The composition, properties and structure of octadecyl acrylate from different preparation methods were identified and evaluated by melting point and boiling point test, elementary analysis, IR spectroscopy and 1H NMR spectroscopy. The experimental results showed that the two octadecyl acrylate products are similar in physical and structural characteristiics. The melt direct esterification is a more efficient and reliable preparation method for octadecyl acrylate because of the smaller amount of catalyst and inhibitor used and the higher yield.