Anion and cation effects of ionic liquids and ammonium salts evaluated as dehydrating agents for super-heavy crude oil: Experimental and theoretical points of view

Anion and cation effects of ionic liquids and ammonium salts evaluated as dehydrating agents for super-heavy crude oil: Experimental and theoretical points of view

Type	Journal Article
Author	César A. Flores
Author	Eugenio A. Flores
URL	http://www.sciencedirect.com/science/article/pii/S0167732214001457
Volume	196
Pages	249-257
Publication	Journal of Molecular Liquids
Date	August 2014
Abstract	Researchers examined a series of ionic liquids (IL), [TOA]+ [Y] (where [Y]− = [Cl]−, [HSO4]− or [H2PO4]−), and new ammonium salts, [OCD]+ [Y]− (where [Y] = [HSO4]−, [MeSO3]− or [MePhSO3]−), as demulsifying agents for super-heavy crude oil, at API = 6.39° (MO1) and API = 7.13° (MO2), with 8.46 and 8.94 wt.% of asphaltenes, respectively, at dosages of 1000 and 1500 ppm, using a conventional heating bottle test. The molecular volume (VM), molecular refractivity (MR), dipolar moment (μ) and mean polarizability (α) of the cation and anion fragments were important factors driving the dewatering process. VM, MR and α exhibited a direct relationship with water removal efficiency. Furthermore, absolute softness and the electrophilicity index of the cation fragments were calculated at the density functional theory (DFT) level. An increase in the softness and electrophilicity of the cations correlated with lesser effectiveness as demulsifiers. The partition coefficient of the cations revealed that if the viscosity of the crude oil is low, it is possible to use ILs with a low partition coefficient (log P), but if the viscosity is high, the log P of IL should be near the [TOA]+ [Cl]− value.