光促进温和条件下卤代烃的羰基化反应研究

【作者】 谷杨；

【导师】 高大彬； 孙琢琏；

【作者基本信息】 大连理工大学 ， 应用化学， 2002， 硕士

【摘要】 近年来，光促进烯烃在常温常压下与一氧化碳和醇的氢甲酯化反应引起了人们的关注，它也是制备羧酸甲酯的重要方法。而成本相对低廉、品种繁多的卤代烃的光促进氢甲酯化反应研究较少。本文以一系列不同类型的卤代烃为底物，以非贵金属钴盐作催化剂，常温常压条件下实现了羰基化反应，有选择性的得到了甲酯化产物。 本文考察了苄基氯，氯乙酸乙酯，溴代环己烷，碘代正丁烷，溴代正丁烷，溴代正戊烷，氯代正丁烷等卤代烃底物，发现多种卤代烃在适当条件下均可在温和条件下进行光促进羰基化反应，生成相应正构酯和异构化产物，研究了各种因素对反应的影响，发现钴盐是很好的催化剂，醋酸钠是非常好的添加物，其促进作用远强于其它添加物。加入适宜的醋酸钠量，可提高反应的产率和选择性。 以二氧化碳代替一氧化碳，其它条件不变，适当延长光照时间，发现有类似的反应及规律存在，只是酯的产率和选择性不及与一氧化碳的反应。但由于二氧化碳的化学不活泼性，以及每年巨大排放量所造成的环境问题，它参与的羰基化反应就成为一个重要又富有潜力的课题，是绿色化学一个崭新的研究领域。 本文还以ESR谱对苄基氯与二氧化碳的光促进羰基化反应进行了机理探索，发现体系中通入二氧化碳光照后有CO₂^-自由基中间体生成，据此实验结果和文献记载，对该反应的机理进行了推测。更多还原

【Abstract】 Recently photopromoted hydroesterification of olefins with carbon monoxide under room temperature and normal pressure arises people’s interests, which is also an important method to prepare methyl ester. There are few researches on the photopromoted hydroesterification of relatively low cost halides. In this paper, using a series of different types of halides as substrates, non-precious metal cobalt salts as catalyst, methyl esters are selectively obtained.The halides used as substrate include benzyl chloride, chloroacetic acid ethyl ester, bromocyclohexane, iodobutane(n-), bromobutane(n-), chlorobutane (n-),bromopentane(n-), etc. Given the appropriate conditions, they can be photopromoted carbonylized under room temperature and normal pressure, with esters as products. The influences of various factors are investigated, cobalt salts are good catalysts, sodium acetate is effective additive, whose ability of promotion is much better than that of other additives. Certain amount of sodium acetate added, the yield and selectivity of the reaction can increase significantly.Using carbon dioxide instead of carbon monoxide and increasing irradiation time,the same reactions and results are obtained,with disadvantages that the yield and selectivity of esters are not satisfying compared with the carbonylation of carbon monoxide. Due to the chemical inactivity of carbon dioxide and the environmental problems it caused, the carbonylation using carbon dioxide becomes an important topic with potentiality and a new area of green chemistry.The mechanism of carbonylation of benzyl chloride with carbon dioxideis investigated by ESR (Electron Spin Resonance),finding that carbon dioxide after irradiation changes to CO2 radicals, therefore a mechanism is derived under the guidance of experimental results and references.更多还原