摘要
以钨酸钠、磷酸、过氧化氢H2O2和氯代十六烷基吡啶为原料制备了磷钨杂多酸季铵盐相转移催化剂.实验发现,采用乙酸乙酯溶解氯代十六烷基吡啶制备的催化剂呈颗粒状析出于油水界面,简单过滤即可分离.该催化剂与H2O2作用体系呈均相,反应速率显著加快.H2O2耗尽并降温后,催化剂以固体颗粒形式沉淀,回收率达90%,重复使用六次活性基本不变.采用FT-IR表征了反应前后催化剂结构的变化.以二氯乙烷为溶剂考察了反应条件对脂肪酸甲酯环氧化反应和H2O2利用率的影响.实验结果表明,在反应时间2.5h,催化剂0.3g,分步加入30%H2O23.5g(30.88mmol),反应温度65℃,二氯乙烷20mL,脂肪酸甲酯5.0g(双键22.84mmol)时,产品环氧值可达5.78%,双键环氧化选择性81.9%,H2O2利用率达86%.
A heteropolyphosphatotungstate for the epoxidation of fatty acid methyl esters was prepared using sodium tungstate,phosphoric acid,hydrogen peroxide and cetyl pyridinium chloride. It was found that catalysts prepared by dissolving cetyl pyridinium chloride with ethyl acetate aggregate between the interface of organic phase and water phase. The catalyst was separated by simple filtration. The action of the title catalyst with H2O2 leads to a formation of homogeneous phase and an accelerated reaction rate. The catalyst will precipitate in solid particles with the consumption of H2O2 and the decreasing temperature,its recovery is up to 90% and catalytic activity is almost unchanged after six consecutive uses. The catalyst structures before and after epoxidation reaction were characterized by FT-IR. The effect of reaction conditions on the epoxidation and H2O2 utilization was investigated. Under the conditions of reaction time 2.5 h,catalyst 0.3 g,stepwise addition of 30 % H2O2 3.5 g（30.88 mmol）,reaction temperature 65 ℃,1,2-dichloroethane 20 mL,FAMEs 5.0 g（22.84 mmol double bond）,the product epoxy value is up to 5.78%,double bond epoxidation selectivity 81.9% and H2O2 utilization 86%.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2010年第3期222-227,共6页
Journal of Molecular Catalysis(China)
基金
河北省教育厅科技攻关课题
课题编号2008439)
关键词
脂肪酸甲酯
环氧化
相转移催化
过氧化氢
磷钨杂多酸
增塑剂
Fatty acid methyl ester
Epoxidation
Phase-transfer catalyst
Hydrogen peroxide
Phosphotungstic acid
Plastizer
