Estimation of the vapour pressure of non-electrolyte organic compounds via group contributions and group interactions

A new group contribution method for the prediction of liquid vapour pressures for non-electrolyte organic compounds is presented. The model represents both a significant improvement and extension of the original method developed by Nannoolal et al. The method was developed with the aid of the Dortmund Data Bank, which contains over 180 000 data points for both solid and liquid vapour pressure (2007). Group parameters were regressed to a training set of nearly 114 000 data points for more than 2330 compounds. As in the case of the method of Nannoolal et al. the new model only requires knowledge about the molecular structure and a single vapour pressure point in order to generate the vapour pressure curve. In the absence of experimental data it is possible to predict the normal boiling point by a method developed earlier by Nannoolal et al. The relative error in pressure was found to be 5.0% (113 888 data points for 2332 compounds) which compares favourably with the previous model (6.6% for 111 757 data points and 2207 compounds).