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›› 2020, Vol. 37 ›› Issue (5): 599-605.DOI: 10.7523/j.issn.2095-6134.2020.05.004

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Oligomerization of isobutene catalyzed by combined proton acidic ionic liquids

YU Xiaojia1,2, LIU Ying2, WANG Hui2, WU Youqing1, GUO Yanqiu2   

  1. 1. School of Resources and Environment Engineering, East China University of Science and Technology, Shanghai 200237, China;
    2. CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2019-03-21 Revised:2019-05-13 Online:2020-09-15
  • Supported by:
     

Abstract: Two proton acidic imidazolium-based ionic liquids(ILs) of 1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate ([NNS][CF3SO3]) and 1-(4-sulfobutyl)-3-methylimidazolium hydrosulfate ([NNS][HSO4]), were synthesized and applied in the oligomerization of isobutene. Some important parameters, including the types of ionic liquids, amount of catalysts, the reaction temperature, the reaction time, molar ratios of two ILs, stirring method and speeds, were screened. The optimized reaction conditions were determined as follows, 5 mmol of catalyst, 100 ℃, 3 h, and molar ratio of 1:1 for the two ILs. Under these conditions, the catalytic activity of the complexed ILs reached the highest with conversion rate of 84% for isobutene and selectivity of 77% for C8=. The complex ILs could be recycled six times without obvious loss of catalytic activities, and conversion rate of isobutene remained 70% with above 90% selectivity of C8=. The reaction was monitored on NMR and the formation process was further determined.

 

Key words: oligomerization, isobutene, proton acidic ionic liquid, highly selective dimerization

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