以水为介质的氧化反应是一种有效的烯烃选择性绿色氧化和有机物的绿色处理过程.以苯乙烯为反应底物,开展了苯乙烯在室温、紫外光照射下的有机-水两相界面上的分子氧选择性光氧化反应.结果表明:在水溶液中,苯乙烯被选择性地光氧化成苯甲醛,苯甲醛的产率和选择性分别为28.5％和90.8％;而在无氧状态下,水溶液和有机溶剂中的苯乙烯光氧化反应都只得到非常少量的苯甲醛,产率仅有0.2％ ～0.4％.芳香端基烯烃(如3-甲基苯乙烯、4-甲氧基苯乙烯、1,1-二苯基乙烯)也能在水溶液中被分子氧选择性地光氧化,生成相应的羰基化合物;以双氧水为氧化剂,在水溶液中苯乙烯光氧化反应的苯甲醛产率为0.4％,以双氧水或分子氧为氧化剂时,醇溶剂中苯甲醛的产率均为0.6％ ～0.7％.研究显示,分子氧和水是苯乙烯光氧化反应的必须因素.%An oxidation process with water as the reaction medium might be effective in selective green oxidation of olefins and green oxidation treatment of organic compounds.The photooxidation of styrene by molecular oxygen was investigated in organic/water biphasic media at room temperature under UV light irradiation.The results indicated that the photoreaction,which occurred in aqueous medium,gave a high selectivity (90.8％) of the product,benzaldehyde,with a formative yield of 28.5％.The photoreaction which occurred in aqueous solution and organic solvents without molecular oxygen gave little amount of benzaldehyde with a yield of 0.2％-0.4％.The photooxidation process was also operative for the oxidation of several styrene derivatives (e.g.,3-methylstyrene,4-methoxylstyrene and 1,1-diphenylethylene),which can be selectively photooxidized into the corresponding aldehydes or ketones.The photoreaction which occurred in aqueous medium with hydrogen peroxide as oxidants gave benzaldehyde yield of 0.4％.However,the photoreaction which occurred in alcohol solvent with hydrogen peroxide or molecular oxygen as oxidants gave little amount of benzaldehyde with a yield of 0.6％-0.7％.The experiments indicated that both molecular oxygen and water are essential to photooxygenatiou reaction of styrene.
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