Critical temperatures and pressures of hydrocarbons

Abstract

A method has been developed for the calculation of van der Waals' constants both a and b for hydrocarbons usually encountered, including the aliphatic, naphthenic, and aromatic types. With these constants critical temperatures and pressures can be calculated directly.Methods recently made available (12, 13, 14, 15) allow the calculation of these constants through the use of substitution values involving the replacement of hydrogen atoms by methyl groups in a definitely prescribed pattern. In this study van der Waals' constants are directly calculated from a consideration only of the molecular structure of the hydrocarbon. This approach has become possible through the assignment of group contributions to different types of carbon atoms, which can be combined in any manner to produce the van der Waals' constants representative of the molecular structure of the hydrocarbon.