Phase behaviors of two- and three-component mixtures 'alpha-pinene-water' and 'alpha-pinene-ethanol-water' were studied over a wide range of their composition, temperature, and pressure. Conditions were found that provide heteroazeotropic states of binary mixture 'alpha-pinene-water' and ternary mixture 'alpha-pinene-ethanol-water' depending on the ratio of 'water/(alpha-pinene+ethanol)' fractions at the 'alpha-pinene+ethanol' ratio of 1:1. Critical curves were Calculated to demonstrate an anomalous dependence of these Curves on the mixture composition, with the temperature minimum points typical of the mixtures that form heteroazeotropes. (c) 2008 Elsevier Ltd. All rights reserved.