磷钨酸季铵盐催化制备环氧化桐油甲酯及其性能研究

摘要

以磷钨酸、30％H2O2和十二烷基氯化吡啶为原料制备了磷钨酸季铵盐相转移催化剂(C12H25C6H5N)3[PW4O16],并将该催化剂用于催化桐油甲酯(TOME)合成环氧桐油甲酯(ETOME),考察了不同反应条件对TOME环氧化反应的影响.研究发现:该相转移催化剂与H2 O2和TOME相互作用的体系可以视为均相反应,且反应速率快,当n(C=C):n(H2O)为1:1.6,TOME和催化剂的质量比1:0.03,反应温度为50℃,反应时间为3h时,制得的ETOME的环氧值达到4.9％;热重(rG)分析表明桐油(TO)、TOME和ETOME的热稳定性顺序为ETOME＞ TO＞ TOME.%A quaternary ammonium phosphotungstates phase transfer catalyst (C12 H25C6H5N) 3 [PW4O16] was synthesized by using phosphotungstic,hydrogen peroxide(30％) and dodecylpyridinium chloride as feedstock.This phase transfer catalyst was used for the epoxidation of tung oil methyl ester(TOME) and manufacture the epoxidized tung oil methyl ester(ETOME).It was found that the system consist of phase transfer catalyst,TOME and hydrogen peroxide can be regarded as a homogeneous system and the reaction rate was accelerated.Effect of different conditions on the epoxidation reaction of methyl tung oil was investigated.Results showed that the optimum conditions were 50 ℃ reaction temperature,3 h reaction time,1.6:1 molar ratio of hydrogen peroxide to double bond and catalyst dosage was 3.0％.The epoxy value of ETOME can reach 4.9％ under these optimum condition.Thermogravimetric analysis showed that the descending order of thermal stability of the products was ETOME ＞ TO ＞ TOME.