High solubilities of small hydrocarbons in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate

Xiangyang Liu; Waheed Afzal; Guangren Yu; Maogang He; John M Prausnitz

doi:10.1021/jp403460a

High solubilities of small hydrocarbons in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate

J Phys Chem B. 2013 Sep 12;117(36):10534-9. doi: 10.1021/jp403460a. Epub 2013 Aug 30.

Authors

Xiangyang Liu¹, Waheed Afzal, Guangren Yu, Maogang He, John M Prausnitz

Affiliation

¹ Department of Chemical and Biomolecular Engineering, University of California , Berkeley, California, 94720-1462, United States.

PMID: 23947453
DOI: 10.1021/jp403460a

Abstract

Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P(14)666][TMPP] from 313 to 353 K up to 6.7 MPa. A literature review on solubilities of small hydrocarbons in ionic liquids shows that solubilities in [P(14)666][TMPP] are appreciably larger than those in other ionic liquids. Contrary to solubilities in ionic liquids studied earlier, solubilities of paraffins (ethane and propane) in [P(14)666][TMPP] are larger than those of the corresponding olefins (ethylene and propylene). Because, at fixed temperature, the vapor pressure of an olefin is larger than that of the corresponding paraffin, the relative volatility of the olefin exceeds that of the corresponding paraffin, contrary to the relative volatility observed in conventional extractive distillation with polar solvents where the volatility of the paraffin exceeds that of the corresponding olefin.