摘要
制备了多种季铵盐离子液体,考察了不同阴阳离子的离子液体对苯与苯酐酰基化合成邻苯甲酰苯甲酸(BBA)反应的催化性能。采用FTIR、紫外吸收光谱与Hammett酸强度函数联用的方法对离子液体进行表征,并借助量化计算分析反应路径。实验结果表明,不同阴离子的Et_(3)NHCl离子液体催化活性的高低顺序为:Et_(3)NHCl-2.5AlCl_(3)>Et_(3)NHCl-2.5FeCl_(3)>Et_(3)NHCl-2.5ZnCl_(2);不同阳离子的季铵盐类AlCl_(3)离子液体酸强度的大小顺序为:Me_(3)NHCl-2.5AlCl_(3)>Et_(3)NHCl-2.5AlCl_(3)>C_(6)H_(13)NHCl-2.5AlCl_(3)>(C_(4)H_(9))_(3)NHCl-2.5AlCl_(3)>(C_(8)H_(17))_(3)NHCl-2.5AlCl_(3)。Et_(3)NHCl-2.5AlCl_(3)为该酰基化反应的较好催化剂,较优的合成条件为:n(AlCl_(3))∶n(Et_(3)NHCl)=2.5,80℃下反应3 h。Et_(3)NHCl-2.5AlCl_(3)催化苯与苯酐反应的最佳条件为:n(苯)∶n(Et_(3)NHCl-2.5AlCl_(3))∶n(苯酐)=5∶2∶1,45℃下反应4 h;该条件下BBA收率可达95.7%。密度泛函量化计算结果表明,Et_(3)NHCl-2.5AlCl_(3)催化苯与苯酐酰基化反应接近碳正离子机理。
The catalytic performence of quaternary ammonium ionic liquids with different anions and cations for synthesizing o-benzoylbenzoic acid(BBA)from benzene and phthalic anhydride was investigated.The ionic liquids were characterized by FTIR,UV spectroscopy,as well as Hammett acid strength function,and the reaction pathway was analyzed by quantification calculation.The catalytic activity of ionic liquids with different anions was in order of Et_(3)NHCl-2.5AlCl_(3)>Et_(3)NHCl-2.5FeCl_(3)>Et_(3)NHCl-2.5ZnCl_(2).In terms of acid strength,the sequences of ionic liquids with different cations was Me_(3)NHCl-2.5AlCl_(3)>Et_(3)NHCl-2.5AlCl_(3)>C_(6)H_(13)NHCl-2.5AlCl_(3)>(C_(4)H_(9))_(3)NHCl-2.5AlCl_(3)>(C_(8)H_(17))_(3)NHCl-2.5AlCl_(3).Et_(3)NHCl-2.5AlCl_(3) showed high catalytic performance for the acylation reaction,and the optimal preparation conditions of Et_(3)NHCl-2.5AlCl_(3) were n(AlCl_(3))∶n(Et_(3)NHCl)2.5,reaction temperature of 80℃,and reaction time of 3 h.The best reaction conditions for synthesizing BBA over Et_(3)NHCl-2.5AlCl_(3) were as follows∶n(benzene)∶n(Et_(3)NHCl-2.5AlCl_(3))∶n(phthalic anhydride)5∶2∶1,reaction temperature of 45℃,and reaction time of 4 h.Under these conditions,the yield of BBA reached 95.7%.On the basis of density functional quantification calculation,the reaction for synthesizing BBA over Et_(3)NHCl-2.5AlCl_(3) was consistent with the mechanism of carbenium ion.
作者
王桂荣
闫云
杨秋生
赵新强
王延吉
Wang Guirong;Yan Yun;Yang Qiusheng;Zhao Xinqiang;Wang Yanji(School of Chemical Engineering and Technology,Hebei University of Technology,Tianjin 300130,China)
出处
《石油化工》
CAS
CSCD
北大核心
2022年第2期115-123,共9页
Petrochemical Technology
