The extraction of pyridine-3-carboxylic acid was investigated using N-methyl-N,N-dioctyloctan-1-ammonium chloride (TOMAC) with different diluents having distinct functional groups. Nine diluents were used in the study, i.e., octan-1-ol, nonan-1-ol, decan-1-ol, ethyl ethanoate, propyl ethanoate, heptan-2-one, octan-2-one, octane, and decane. The measurements were performed at room temperature (T = 298 K). The experimental results of batch extractions were used to calculate distribution coefficients (K-D), loading factors (Z), and extraction efficiency (E). The maximum distribution coefficient (K-D = 2.335) was obtained with octan-1-ol, and its extraction efficiency was 70.16 %. Besides, the highest loading factor was reached to a value of (0.179 at 0.440) mol.kg(-1) equilibrium amine concentration. The results of the liquid-liquid equilibrium measurements were correlated by a linear solvation energy relationship (LSER) model which takes into account physical interactions. Experimental and model results of pyridine-3-carboxylic acid extraction from aqueous solution was compared. LSER model has been applied to experimental results with 0.98 R square.