Phase equilibria of the systems (water + pyruvic acid + high boiling alcohol) have been determined at T = 298.2 K. Among the heavy alcohol solvents studied, 1-decanol gives the largest distribution ratio and separation factors for extraction of pyruvic acid. The distribution data of pyruvic acid are used to establish the basis for an analytical structure to provide optimum extraction. Some aspects of selection of an appropriate criterion for designing optimum extraction of acid are discussed. The solvation energy relation (SERLAS) with 5- and 10-parameters has been performed to correlate the (liquid + liquid) equilibria (LLE) of associated systems containing a protic alcohol solvent capable of hydrogen bonding. The extraction equilibria were also predicted through the UNIFAC-original model. The reliability of both models has been analyzed against the LLE data with respect to the distribution ratio and separation factor. (C) 2012 Elsevier Ltd. All rights reserved.