Journal of Chemical Thermodynamics, Vol.70, 122-126, 2014
Unusual trend of viscosities and densities for four ionic liquids containing a tetraalkyl phosphonium cation and the anion bis(2,4,4-trimethylpentyl) phosphinate
Densities and viscosities are reported for three similar ionic liquids, all with anion bis(2,4,4-trimethylpentyl) phosphinate [TMPP]. The hydrocarbon chains attached to the phosphonium cation vary in length; the three cations are tetrabutylphosphonium [P4444], trimethyloctylphosphonium [P8111] and tributylmethylphosphonium [P1444]. Contrary to expectation, neither the densities nor the viscosities show a monotonic trend with the length of the hydrocarbon chains on the cation. (C) 2013 Elsevier Ltd. All rights reserved.