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机构地区:[1]郑州大学化工与能源学院,河南郑州450001
出 处:《高校化学工程学报》2010年第4期614-619,共6页Journal of Chemical Engineering of Chinese Universities
基 金:河南省高校科技创新人才计划(2010HASTIT037)
摘 要:以氯甲基化大孔聚苯乙烯-二乙烯苯交联树脂(PS)为载体与叔胺进行季铵化、与磷钨杂多化合物离子交换制得了PS接枝季铵磷钨杂多酸盐催化剂。对催化剂进行了FT-IR、XPS和BET分析,并将催化剂用于无搅拌条件下的相界相转移催化环辛烯双氧水环氧化反应;讨论了催化剂结构、催化剂用量、双氧水质量分数、双氧水和环辛烯摩尔比、反应温度等因素对反应的影响。结果发现具有三乙醇胺结构的催化剂因亲水性较强处于下层水相而不能用于相界相转移催化反应;而具有长直碳链季铵盐结构的催化剂因具有合适的亲水性和亲油性,能处于环辛烯和双氧水的界面处,可用于无搅拌情况下的相界相转移催化反应。室温下环氧环辛烷的产率可达99%以上;提高反应温度、双氧水质量分数等可明显提高反应速度。催化剂可至少重复使用五次而活性无明显下降。Using chlorine methyl PS as loading material,through quaternary amination with tertiary amine and ion-exchange with phosphor-tungstic heteropoly compounds,the PS grafted quaternary ammonium phosphor tungsten heteropoly acid salt catalysts were prepared and were characterized by FT-IR,XPS and BET.The prepared catalysts were used in the phase boundary phase transfer catalysis (PBPTC) for epoxidation of cyclooctene (COE) by aqueous hydrogen peroxide (HP).The factors affecting the epoxidation reaction,such as the structure of catalyst,amount of catalyst used,mass fraction of HP,molar ratio of HP to COE,reaction temperature and so on,were studied.The results show that,since those catalysts with the structure of triethanolamine quaternary ammonium salt will lay in the lower HP phase due to their strong hydrophilicity and can't contact with the upper COE layer,they can't act as phase boundary phase transfer catalysts for epoxidation of COE with HP;while those catalysts with long carbon chain quaternary ammonium salt structure will lay at the liquid-liquid phase boundary area between upper COE phase and lower HP phase due to their amphiphilicity and can act as phase boundary phase transfer catalysts for epoxidation of COE with HP in stirring-free condition.Using the prepared catalyst with long carbon chain quaternary ammonium salt structure,the yield of 1,2-epoxycyclooctane can reach over 99% at room temperature.The reaction rate can be obviously increased by increasing the mass fraction of HP or reaction temperature.Moreover,the prepared catalyst can be reused for five times without obviously decreasing its catalytic activity.
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