Deep separation of benzene from cyclohexane by liquid extraction using ionic liquids as the solvent

Teng Zhou, Ziyun Wang, Yinmei Ye, Lifang Chen, Jing Xu, Zhiwen Qi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)


Separation of benzene and cyclohexane is one of the most important and difficult processes in the petrochemical industry, especially for low benzene concentration. In this work, three ionic liquids (ILs), [Bmim][BF 4], [Bpy][BF 4], and [Bmim][SCN], were investigated as the solvent in the extraction of benzene from cyclohexane. The corresponding ternary liquid-liquid equilibria (LLE) were experimentally determined at T = 298.15 K and atmospheric pressure. The LLE data were correlated with the nonrandom two-liquid model, and the parameters were fitted. The separation capabilities of the ILs were evaluated in terms of the benzene distribution coefficient and solvent selectivity. The effect of the IL structure on the separation was explained based on a well-founded physical model, COSMO-RS. Finally, the extraction processes were defined, and the operation parameters were analyzed. It shows that the ILs studied are suitable solvents for the extractive separation of benzene and cyclohexane, and their separation efficiency can be generally ranked as [Bmim][BF 4] > [Bpy][BF 4] > [Bmim][SCN]. The extraction process for a feed with 15 mol % benzene was optimized. High product purity (cyclohexane 0.997) and high recovery efficiency (cyclohexane 96.9% and benzene 98.1%) can be reached.

Original languageEnglish
Pages (from-to)5559-5564
Number of pages6
JournalIndustrial and Engineering Chemistry Research
Issue number15
Publication statusPublished - 18 Apr 2012

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Chemistry(all)
  • Industrial and Manufacturing Engineering


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