A phosphonium ionic liquid with glyceryl moiety was synthesized and used as an efficient extractant in the removal of sulfur compounds from a model liquid fuel. The effects of different parameters such as volume ratio, time, initial concentration, temperature and type of sulfur compound on the desulfurization efficiency were investigated. The reusability and the recyclability of the described ionic liquid in the extractive desulfurization were also studied. For comparison, another ionic liquid with two acidic moieties was synthesized and used in the extractive desulfurization. To understand the mechanism of the extractive desulfurization by the phosphonium ionic liquid, a computational study consisting of structural investigations, interaction energy, NBO, AIM and EDA analysis on the type and nature of the interaction between dibenzothiophene (DBT) and the prepared ionic liquid was also performed. The obtained results of this research support the idea of rational design, synthesis and application of the task specific extractants for the green desulfurization of liquid fuels. (C) 2017 Elsevier Ltd. All rights reserved.