Highly efficient and selective electrophilic and free radical catalytic bromination reactions of simple aromatic compounds in the presence of reusable zeolites
Highly efficient and selective electrophilic and free radical catalytic bromination reactions of simple aromatic compounds in the presence of reusable zeolites
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DOI：
10.1039/b002157l
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
Keith Smith;G. El‐Hiti;M. E. Hammond;D. Bahzad;Zhaoqiang Li;C. Siquet
中科院分区：
文献类型：
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作者：
Keith Smith;G. El‐Hiti;M. E. Hammond;D. Bahzad;Zhaoqiang Li;C. Siquet
在化学计量量的NaY沸石存在下，中等活性的单取代芳族化合物与溴的反应以高产率和对相应的对溴产物的高选择性进行。沸石可以很容易地通过加热再生和重复使用。在甲苯的情况下，通过使用次溴酸叔丁酯作为试剂，沸石HX作为催化剂，和包含四氯化碳和乙醚的混合物的溶剂，可以实现类似的对位选择性。在光的存在下，用溴对4-甲基苯甲酸乙酯进行自由基溴化反应，得到了高产率的4-（溴甲基）苯甲酸乙酯，但对单溴化反应的选择性没有很大的提高。
Reactions of mono-substituted aromatics of moderate activity with bromine in the presence of stoichiometric amounts of zeolite NaY proceed in high yield and with high selectivity to the corresponding para-bromo products. The zeolites can easily be regenerated by heating and reused. Similar para-selectivity can be achieved in the case of toluene by use of tert-butyl hypobromite as reagent, zeolite HX as catalyst, and a solvent comprising a mixture of tetrachloromethane and diethyl ether. Radical bromination of ethyl 4-methylbenzoate using bromine in the presence of light is catalysed by various zeolites and affords a high yield of ethyl 4-(bromomethyl)benzoate but with no great improvement in selectivity for monobromination.