Application Of Pyrrolidone Ionic Liquids On Esterification Reacations

In this paper,pyrrolione ionic liquids were prepared by one-pot methods.The synthesis of ethyl acetate by ethanol and acetic acid was applied as model reactions to test their esterification activity.Results show that the pyrrolione ionic liquids were catalytically efficient for the esterification reactions and that is comparable to or even higher than H2SO4.Then,the stability of ionic liquids was investigated further by recycling tests.It was found that the pyrrolione ionic liquids have great stability.Especially,[NEP][TsO]could be used for 30 times and the activity only decreased by 13.58%.Therefore,the[NEP][TsO]has good catalytic performance for the choosen esterification reaction.The structure of ionic liquid was characterized by FT-IR,1HNMR and the thermal stability was measured by DTG analysis.It was observed that the pyrrolione ionic liquids have better stability in the temperature reange from 150 ? to 200 ?.This is in close relation to the structure of cations;that is,the bigger the alkyl groups,the more stable the ionic liquids will be.The preparation conditons were then optimized by varying the molar ratios of raw materials,preparation times,preparation temperature,and so on.It was found that the yield of[NEP][TsO]could reach 99%under the optimum conditions with w:n(NEP):(TsOH)=1.2:1,4 h,and 110 ?.We have preparaed 400 kg ionic liquids in a 50 L batch reactor and realized successful industrial application on a 50000 t/y esterification equipment for ethyl acetate production.Finally,the ionic liquids were further applied to other esterification reactions such as the synthesis of DMA and methyl acetoacetate.The experimental results showed that ionic liquid could replace H2SO4 as the esterification catalyst.The selectivity of DMA from adipic acid was 99.9%by reactive distillation methods under optimized conditions:reaction temperature being 105 ?,the reflux ratio being 3:1,F(raw material):F(met-hanol)being 0.3:1.1.The selevtivity of methyl acetoacetate reached 97.47%through batch reactions when DK was 50 g,methanol was 22.85 g,triethylamine was 0.5 g,and the IL was 0.5 g.By-products were occupied by low boiling point matters,such as methanol and acetone,indicating a facile way of separating and purification...