碳酸二辛酯的合成工艺研究

Process reserach on the synthesis of dioctyl carbonate

采用固体碱K2CO3/γ-Al2O3为催化剂,以碳酸二乙酯和正辛醇为主要原料经催化酯交换合成了碳酸二辛酯。采用气相色谱监测反应液中碳酸二辛酯的含量,考察了催化剂用量、物料配比、反应温度与时间以及催化剂重复使用次数对碳酸二辛酯含量的影响。结果表明,固体碱K2CO3/γ-Al2O3对反应有较高的催化活性。经优化的合成工艺为:正辛醇与碳酸二乙酯摩尔比为2.3∶1,催化剂质量用量占碳酸二乙酯的3%,150℃下反应2h,后升温至160℃反应1h,最后再升至170℃反应1h,产品经减压精馏后含量在99.2%以上,单程反应收率可达85%以上,催化剂回收后可重复使用3次以上。

Dioctyl carbonate was synthesized with K2CO3/γ-Al2O3 as catalyst and diethyl carbonate and n-octanol as the main raw materials by catalyzed transesterification.The content of dioctyl carbonate in the reaction solution was monitored by gas chromatography.The effects of catalyst dosage,the molar ratio of alcohol to ester,reaction temperature and time and the number of times of catalyst reuse on the content were investigated.The results showed that the K2CO3/γ-Al2O3 had high catalytic activity for the reaction.The optimized synthesis process was as follows:the molar ratio of n-octanol to diethyl carbonate was 2.3∶1,the catalyst dosage was 3%diethyl carbonate,the reaction lasted for 2 hours at 150℃,and then rose to 160℃for 1 hour,and finally rose to 170℃for 1 hour.The content is above 99.2%after the raw product is subjected to vacuum distillation,and the single-pass reaction yield could reach more than 85%.The catalyst could be reused after being recycled.