酸性离子液体高选择性催化合成2,6-二甲基萘  

High Selective Synthesis of 2,6-Dimethylnaphthanlene Catalyzed by Acidic Ionic Liquids

作　　者：吴伟[1] 魏晓丽[1] 武光[2] 李凌飞[2] 张密林[1] 

机构地区：[1]哈尔滨工程大学材料科学与化学工程学院,黑龙江哈尔滨150001 [2]黑龙江大学化学化工与材料学院,黑龙江哈尔滨150080

出　　处：《催化学报》2007年第6期572-578,共7页

基　　金：黑龙江省科学技术计划项目(2006G1660-00);黑龙江省自然科学基金(B0301);哈尔滨市科学研究基金(2004AFXXJ048).

摘　　要：研究了三乙胺氯铝酸盐(Et3NHCl-AlCl3)类离子液体催化剂的酸性及反应条件对1,2,4,5-四甲基苯与2-甲基萘转移烷基化合成2,6-二甲基萘(2,6-DMN)反应的影响规律.结果表明,通过调节Et3NHCl-AlCl3离子液体的酸强度和优化反应温度及反应时间等工艺条件可以高选择性地制备2,6-DMN.以Et3NHCl-AlCl3(x(AlCl3)=0.71)为催化剂,以环己烷为溶剂,在2-甲基萘∶四甲基苯摩尔比为1∶1和20℃的条件下反应6h,2-甲基萘的转化率可达48.8%,DMN的选择性和2,6-DMN占DMN的摩尔百分比分别达到81.2%和52.4%,2,6-DMN的收率可达20.8%.特别需要指出的是,在此优化条件下反应2h,2-甲基萘的转化率为3.7%时,2,6-DMN占DMN的摩尔百分比达到100%.以混合甲基萘和萘为转移烷基化反应原料时也高选择性地得到了2,6-DMN.对Et3NHCl-AlCl3的循环使用性能进行了考察,并分析了失活原因.The transalkylation of 1,2,4,5- tetramethylbenzene （TeMB） with 2-methylnaphthalene （2-MN） to synthesize 2,6-dimethylnaphthalene （2,6-DMN） by ionic liquid Et3NHCl-AlCl3 was investigated, and the effects of the acidic strength of the ionic liquid and the reaction conditions on the transalkylation were studied. The results showed that a high selectivity for 2,6-DMN can be obtained by controlling the acid strength of the ionic liquid and optimizing the reaction conditions. Using cyclohexane as the solvent and Et3NHCl-AlCl3 （x （AlCl3） =0.71） as the catalyst, 48.8% 2-MN conversion, 81.2% selectivity for DMN, 52.4% molar ratio of 2,6- DMN/total dimethylnaphthalenes, and 20.8 % yield of 2,6-DMN were obtained under the reaction conditions of 20 ℃ , 6 h, and 2-MN ：TeMB molar ratio of 1： 1. In addition, the catalyst exhibited 100 % molar ratio of 2,6- DMN/total dimethylnaphthalenes with 3.7 % 2-MN conversion during 2 h reaction under the optimized reaction conditions. A high selectivity for 2,6-DMN was also obtained when a feed of mixed methylnaphthalene or naphthalene was used. The reuse of the ionic liquid was investigated and the main reason for the catalyst deactivation was discussed.

关 键 词：离子液体 1 2 4 5-四甲基苯 2-甲基萘 转移烷基化 2 6-二甲基萘 

分 类 号：O643.32[理学—物理化学]