Raney Ni催化4-溴联苯加氢降解研究  

Raney Ni-catalyzed hydrodebromination of 4-bromobiphenyl

作　　者：刘琪[1,2,3] 周世伟[1] 马宣宣[1] 刘苏静[1] 杨翠云[1] 夏传海[1] 

机构地区：[1]中国科学院烟台海岸带研究所,烟台264003 [2]中国科学院海洋研究所,青岛266071 [3]中国科学院研究生院,北京100049

出　　处：《环境科学学报》2010年第6期1193-1198,共6页Acta Scientiae Circumstantiae

基　　金："十一五"科技支撑重点项目(No.2008BAC32B03);山东省中青年科学家科研奖励基金(No.BS2009CL006)~~

摘　　要：以4-溴联苯为模型化合物,研究在H2作氢源、RaneyNi作催化剂条件下4-溴联苯的加氢脱溴反应,并调查了溶剂、碱及温度对加氢脱溴的影响,以及不同催化剂的催化效果.结果表明:相比贵金属催化剂(Ru/C、Pt/C、Pd/C),RaneyNi价廉且有较高的催化活性,具有实际应用价值;有机溶剂中添加适量的水可显著促进加氢脱溴反应,在乙醇/水(V/V)=85/15的溶液中,仅30min4-溴联苯就可100%脱溴;而在纯乙醇中,反应60min,尚有10%的4-溴联苯没有降解.另外,碱(NaOH)的加入可明显提高催化剂的活性,n(NaOH)∶n(HBr)=1.1∶1时,仅需30min4-溴联苯就完全被RaneyNi催化加氢降解;而n(NaOH)∶n(HBr)=2∶1时,反应60min,只有约93%的4-溴联苯发生了加氢降解,因此,碱的加入量以超过其化学反应剂量10%为宜.在温和条件(30～45℃、常压约101kPa)下,RaneyNi可催化4-溴联苯完全脱溴产生联苯,同时,联苯作为重要的化工产品可回收再利用.由此可见,多相催化加氢脱溴有望发展成为控制和消减多溴二苯醚等持久性卤代有机污染物的绿色降解技术.In this work,the hydrodebromination of 4-bromobiphenyl over Raney Ni with H2 was studied.The effects of solvent,base,temperature and the catalytic activity of different catalysts on the hydrodebromination of 4-bromobiphenyl were investigated.The results showed that compared with noble-metal catalysts（Ru/C,Pt/C and Pd/C）,low-cost Raney Ni could be employed for practical application due to its higher catalytic activity.The addition of a moderate amount of water to the organic solvent could significantly promote the hydrodebromination of 4-bromobiphenyl.For example,in ethanol/water（V/V）=85/15,the debromination of 4-bromobiphenyl could be completed in 30 minutes;whereas in pure ethanol solvent,10% of 4-bromobiphenyl was still present after 60 minutes.The presence of base（NaOH）could enhance the catalytic activity significantly,and at n（NaOH）∶n（HBr）=1.1∶1,4-bromobiphenyl was completely debrominated in 30 minutes;whereas at n（NaOH）∶n（HBr）=2∶1,about 93% of 4-bromobiphenyl was hydrodebrominated after 60 minutes.So,adding NaOH in 10% excess of the chemical dosage was feasible.Experiments showed that 4-bromobiphenyl could be completely hydrodebrominated by Raney Ni under mild conditions（30~45 ℃ and atmospheric pressure）,and the product was biphenyl,an important industrial chemical,which could be recovered.Therefore,heterogeneous catalytic hydrogenation is promising as an environmentally friendly technology to control and destroy POPs,such as polybrominated diphenyl ethers.

关 键 词：4-溴联苯 RaneyNi 加氢脱溴 多相催化 

分 类 号：X131[环境科学与工程—环境科学]