MAIN PROPERTIES OF SOLVENTS USED IN EXTRACTION AND REQUIREMENTS IMPOSED ON THEM

Abstract

The separation of aromatic hydrocarbons from petroleum fractions remains a critical task in fuel and lubricant production due to increasingly stringent environmental and quality requirements. The growing demand for high-quality motor fuels and the necessity to reduce anthropogenic environmental impact have intensified interest in efficient and selective separation methods. Among the available technologies, liquid–liquid extraction using selective solvents is widely applied because it enables effective separation at relatively low temperatures without significant thermal energy consumption.

This paper reviews the physicochemical properties and performance characteristics of industrially used selective solvents for the extraction of aromatic hydrocarbons, including glycols, sulfolane, dimethyl sulfoxide, N-methylpyrrolidone, and N-formylmorpholine. The advantages and limitations of individual solvents are analyzed in terms of selectivity, solubility capacity, viscosity, boiling point, and regeneration efficiency. Special attention is given to mixed solvent systems, particularly those based on N-methylpyrrolidone and ethylene glycol, which demonstrate enhanced extraction efficiency due to synergistic intermolecular interactions.

Phase equilibrium studies of multicomponent hydrocarbon–solvent systems confirm that mixed solvents can significantly improve the separation of aromatic and non-aromatic hydrocarbons compared to single-component solvents. In addition, the potential application of ionic liquids as alternative extractants is discussed, highlighting their chemical and thermal stability, low volatility, and limitations associated with high viscosity.

The results indicate that the rational selection and optimization of selective solvents, including the use of mixed solvent systems, can substantially enhance the efficiency of aromatic hydrocarbon extraction while reducing energy consumption and environmental impact.