(441b) Investigation of Ionic Liquid Systems for Extraction of Benzoic Acid from Hydrocarbons

Ionic liquids are regarded as green solvents and therefore their application in the field of separation processes such as liquid–liquid extraction is increasing substantially.  In petroleum industry there is a need of separating the aromatic compounds from the crude oil. Currently, most of the oil producing countries are beginning to produce heavy crude oil with high contents of carboxylic acids. The presence of benzoic acid in crude oil could cause severe corrosion to refineries processing units especially those operating at temperature above 230ºC. A new class of solvents, namely the ionic liquids, have recently shown promising application for reducing the acid content in crude oil. This study will investigate the ability of ionic liquids to extract aromatic compounds like benzoic acid from hydrocarbons such as dodecane, cyclohexane and hexane. The selectivity and capacity of ionic liquids for extracting benzoic acid can be determined using COSMOtherm simulation software. For calculating various parameters, this software takes into account the interactions of different molecules surface charges. It can also be used as a tool for the determination of thermo-physical properties of ionic liquids. In this study the effect of solvent, anions and cations of ionic liquids, and the length of carbon chain on the selectivity and capacity are examined. The results indicate that imidazolium based ionic liquids are better than phosphonium based ionic liquids for the extraction of benzoic acid. It was also observed that with the increase in the length of carbon chain the selectivity decreases where as the capacity increases.