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构建了纳米Pd/Fe催化还原甲醇/水中2,2’,4,4’-四溴联苯醚(BDE-47)反应体系,常压下采用单因素实验系统考察了纳米Pd/Fe催化还原甲醇/水中2,2’,4,4’-四溴联苯醚(BDE-47)的主要影响因素,并分析了BDE-47还原反应的中间产物及终产物.结果表明,纳米Pd/Fe的反应活性随Pd负载率的提高而先升后降;甲醇-水体积比高于50∶50后,BDE-47去除率随甲醇-水体积比升高而降低;在25～40℃内,BDE-47去除率随反应温度的升高而升高,随BDE-47初始浓度的增加而降低,增加纳米Pd/Fe量可提高反应速率;酸性及弱碱性条件有利于BDE-47还原.BDE-47还原主要为脱溴反应,是一个从n溴到(n-1)溴联苯醚的逐步脱溴过程,反应进行90min后,BDE-47分子中溴原子完全被脱除,反应终产物为二苯醚.
The catalytic system was established for the catalytic reduction of 2,2 ’, 4,4’-tetrabromodiphenyl ether (BDE-47) in Pd / Fe catalyzed by Pd / Fe. Under normal pressure, single- The main influencing factors of 2,2 ’, 4,4’-tetrabromodiphenyl ether (BDE-47) in methanol / water were analyzed and the intermediates and final products of BDE-47 reduction reaction were analyzed.The results showed that Pd / Fe Reactivity decreased with the increase of Pd loading. When the volume ratio of methanol to water was above 50:50, the removal efficiency of BDE-47 decreased with the increase of methanol / water volume ratio. At 25-40 ℃, The removal rate of BDE-47 increased with the increase of reaction temperature and decreased with the increase of initial concentration of BDE-47. Increasing the amount of nano-Pd / Fe could increase the reaction rate; acidic and weak alkaline conditions were favorable for the reduction of BDE-47. The reduction of BDE-47 is mainly a debromination reaction, which is a gradual debromination process from n-bromine to (n-1) -bromodiphenyl ether. After 90 minutes of reaction, the bromine atom in BDE-47 molecule is completely removed. The product is diphenyl ether.