The recovery of valeric acid from aqueous solutions using several extractants dissolved in different diluents was studied. Commercial extractants Amberlite LA-2 and tributyl phosphate gave the best distribution coefficients. The extraction of valeric acid with Amberlite LA-2 dissolved in toluene was investigated in more detail. The influence of agitation time, agitation rate, extractant concentration and temperature on the equilibrium distribution are reported. Modeling of physical extraction with toluene and reactive extraction with Amberlite LA-2 was carried out using a proposed equilibrium mechanism. The distribution of the valeric acid between water and toluene is regarded as physical extraction taking into account the partial dissociation of the acid in the aqueous phase and its dimerization in the organic phase. The equilibrium behavior with the Amberlite LA-2 is modeled by postulating the formation of various stoichiometric complexes of acid and amine, based on an acid-base-type reaction. The values of the equilibrium constants were obtained via a Levenberg-Marquardt algorithm computer program. The presence and relative proportions of the chemical species were confirmed by means of ¹H NMR studies, thus demonstrating the reliability of the proposed model.