An improved group contribution method is developed for the prediction of boiling points in the context of molecular design. Predictions are based exclusively on the molecular structure of the compound, and for this purpose, UNIFAC-type groups are used. This new model is based on a previous work, which was extended taking into account association effects and modifying the previous method's functionality to achieve a better qualitative and quantitative reproduction of the experimental data. An existing viscosity prediction model is revised and formulated as a group contribution method based also on UNIFAC functional groups. (C) 2013 Elsevier B.V. All rights reserved.