[Bmim]Br-AlCl_3离子液体催化合成二-(3,4-二甲氧基苯基)乙二酮

以自制1-丁基-3-甲基咪唑溴盐-三氯化铝(Bmim]Br-AlCl3)离子液体为催化剂及反应溶剂,催化邻二甲氧基苯与草酰氯的Friedel-Crafts酰基化反应,合成二-(3,4-二甲氧基苯基)乙二酮。研究了几种不同Lew-is酸离子液体、离子液体用量、原料配比、反应温度和反应时间对酰化反应收率的影响。确定了较优的工艺条件:n(Bmim]Br-AlCl3)∶n(邻二甲氧基苯)=1∶1,n(邻二甲氧基苯)∶n(草酰氯)=1∶3,反应温度为15℃,反应时间为8h,在此条件下收率为55.76%。中间体Bmim]Br及产物二-(3,4-二甲氧基苯基)乙二酮的结构经IR、1 H NMR确证。

SYNTHESIS OF BIS-(3,4-DIMETHOXY-PHENYL)ETHANEDIONE CATALYZED BY IONIC LIQUID[Bmim]BR-AlCl3

Bis-(3,4-dimethoxy-phenyl)ethanedione was synthesized via Friedel-Crafts acylation reaction with o-dimethoxy benzene and oxalyl chloride as raw materials,bromide 1-butyl-3-methylimidazolium-alchlor(Br-AlCl3) ionic liquid as catalyst and reaction solvent.Influencing factors on reaction,such as different kinds Lewis acid ionic liquid,dosage of Br-AlCl3,ratio of raw material,reaction temperature and reaction time were investigated.Experimental results show that the optimum conditions are: n(Br-AlCl3)∶n(o-dimethoxy benzene)=1∶1,n(o-dimethoxy benzene)∶n(oxalyl chloride) = 1∶3,reaction temperature was 15 ℃,reaction time was 8 h.Under the conditions,the yield is 55.76%.The structure of the intermediate Br and product bis-(3,4-dimethoxy-phenyl)ethanedione are characterized by IR,1H NMR.