Non-catalytic desulfurization of model diesel using synthesized biodegradable ionic liquid

Abstract

ABSTRACT The conventional processes generally used by petroleum refineries for eradication of sulfur compounds from diesel, namely, diesel hydrotreating is associated with the problem of high cost in terms of energy consumption, catalyst regeneration, etc. The present work has spotted a diesel desulfurization process at ambient temperature (25°C) without using any catalyst. Solvent extraction was applied to eliminate heterocyclic sulfur compounds from model diesel using a novel ionic liquid, which was synthesized from basic raw materials and characterized by common techniques like Fourier Transform Infrared (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR) spectroscopy. A preliminary biodegradation study of the synthesized ionic liquid revealed 49.98% biodegradability after 35 days. The compounds present in the synthesized ionic liquid are 1,3-diethyl-1H-1,2,3-triazol-3-ium acetate ([Etim][OAc]), 1,3-diethyl-1H-imidazol-3-ium ([Eiim][OAc]), and 1-ethyl-3-methyl-3H-pyrazol-1-ium acetate ([EMpim][OAc]). The maximum desulfurization efficiency was 99.09% for dibenzothiophene (DBT) and 97.94% for thiophene using a solvent to feed ratio of 1:1 and applying a stirring time of 60 minutes. The quality of the model diesel has been checked with respect to flash point, aniline point, diesel index, and cetane index both pre- and post-desulfurization.