Phase Equilibria of Binary and Ternary Systems Containing ILs, Dodecane, and Cyclohexanecarboxylic Acid

Martin Atkins, Norfaizah Ab Manan, Johan Jacquemin, Christopher Hardacre, David Rooney

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


This paper reports both the binary and ternary phase behavior of ionic liquids for extracting cyclohexanecarboxylic acid (CCA) from dodecane. This system is a model for the extraction of acids representative of naphthenic acids found in crude oils. In order to develop an effective ternary liquid-liquid extraction system the preliminary selection of ionic liquids was based on CCA miscibility and the dodecane immiscibility with selected ILs. A wide range of ILs based on different cations, anions, cation alkyl-chain length, as well as the effect of temperature on the overall fluid phase behavior is reported. Factors such as variation of cation group, anion effect, alkyl-chain length, and temperature all impact the extraction to various degrees. The largest effects were found to be the lipophilicity of the IL cation and the co-ordination ability of the anion. While CCA capacity increased with lipophilicity of the cation, as did the dodecane. Highly coordinating anions such as trifluoroacetate and triflate demonstrated that highly efficient extraction could be obtained producing favorable tie-lines in the ternary phase diagram. Overall, this study demonstrates that ILs can selectively extract acids from hydrocarbon streams and offers possible treatment solutions for problems associated with the processing of high acid crude oils.
Original languageEnglish
Pages (from-to)312-324
Number of pages13
JournalSeparation Science and Technology
Issue number2
Publication statusPublished - Jan 2012

ASJC Scopus subject areas

  • General Chemistry
  • Process Chemistry and Technology
  • General Chemical Engineering
  • Filtration and Separation


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