In this paper the ability of the UNIFAC methods (original UNIFAC and modified UNIFAC (Dortmund)) to predict the excess molar enthalpies, H-E, is considered. The predicted and the obtained earlier experimental values of the excess molar enthalpies for 5 binary systems of n-propanol, acetic acid, n-propyl acetate, and water were compared. Since the both methods represent the H-E unsatisfactorily, new set of group interaction parameters of the UNIFAC (Dortmund) method for mentioned above compounds was evaluated. (C) 2016 Elsevier B.V. All rights reserved.