Liquid-Liquid Extraction of Phenolic Compounds from Coal Tar Using Mixed Solvent Systems

Abstract

manufacture of resins, pharmaceuticals, dyes, disinfectants, and specialty chemicals. Efficient recovery and separation of these compounds are essential for improving coal tar valorization and reducing environmental impacts associated with byproduct disposal. The present study investigates the liquid–liquid extraction of phenolic compounds from coal tar using mixed solvent systems under controlled operating conditions. The research focuses on evaluating extraction efficiency, phase equilibrium behavior, selectivity, and process optimization associated with mixed solvent extraction systems. Experimental analysis was conducted to examine the influence of solvent composition, extraction temperature, solvent-to-feed ratio, mixing intensity, contact time, and phase separation conditions on phenolic compound recovery and purification performance. Results demonstrate that mixed solvent systems significantly enhance the selective extraction of phenolic compounds through improved solubility interactions and mass transfer mechanisms, resulting in higher extraction efficiency compared with single-solvent systems. The study further reveals that optimized solvent combinations and operating conditions substantially improve phase separation characteristics while minimizing co-extraction of undesirable hydrocarbons. Increased solvent polarity and controlled extraction conditions contributed to enhanced recovery of targeted phenolic fractions and improved process stability. Comparative assessment with conventional extraction techniques confirms the advantages of mixed solvent systems, including higher selectivity, improved extraction kinetics, and reduced energy consumption during downstream purification.