CuCl_(2)-N-甲基咪唑催化合成2,4,4,4-四氯丁腈

Synthesis of 2,4,4,4-tetrachlorobutyronitrile catalyzed by N-methylimidazole-CuCl_(2) complexes

以N-甲基咪唑(N-Mim)与CuCl_(2)·2H_(2)O合成了一系列N-甲基咪唑-CuCl_(2)配合物CuL_(n)Cl_(2)[L为N-甲基咪唑(N-Mim),n=1、2、4]。采用XRD、FTIR及TG对其结构进行了表征。比较了CuL_(n)Cl_(2)催化CCl_(4)与丙烯腈(AN)的原子转移自由基加成(ATRA)反应合成2,4,4,4-四氯丁腈(TBN)的催化性能。考察了反应温度、反应时间、催化剂用量及溶剂的协同催化效应对TBN收率的影响.结果表明,CuL_(2)Cl_(2)的空间配位构建的Cu活性中心呈现最优的催化性能,以乙腈(MeCN)为溶剂,n(CuL_(2)Cl_(2)):n(AN)=1:100,100℃下,反应9 h,TBN的收率可达91.6%,且催化剂可简便回收使用4次而活性无明显降低。基于相关的实验结果,提出了CuL_(2)Cl_(2)催化CCl_(4)和AN的ATRA反应中Cu(Ⅱ)/Cu(Ⅰ)的氧化-还原催化循环机理。

A series of N-methylimidazole-CuCl_(2)complexes CuL(n)Cl_(2)(L=N-methylimidazole=N-Mim,n=1,2,4)were synthesized from N-Mim and CuCl_(2)·2H_(2)O and characterized by XRD,FTIR and TG.The catalytic performance of Cu L_(n)Cl_(2)in the synthesis of 2,4,4,4-tetrachlorobutyronitrile(TBN)by atom transfer radical addition(ATRA)reaction of CCl_(4)and acrylonitrile(AN)were compared.The effects of reaction temperature,reaction time,catalyst dosage and synergistic catalytic effect of solvent on the yield of TBN were investigated.The results showed that the Cu active center constructed by the spatial coordination of CuL_(2)Cl_(2)showed the best catalytic performance.Under the conditions of acetonitrile(MeCN)as solvent,n(CuL_(2)Cl_(2))∶n(AN)=1∶100,the yield of TBN could reach 91.6%at 100℃for 9 h.After being reused for 4 times,and the activity of catalyst did not decrease significantly.Based on the relevant experimental results,the oxidation-reduction catalytic cycle mechanism of Cu(Ⅱ)/Cu(Ⅰ)in the ATRA reaction of CCl_(4)and AN catalyzed by CuL_(2)Cl_(2)was proposed.