A molecular thermodynamic model of gas solubility in nonpolar solvents has been established. The Helmholtz energy of liquid mixture is calculated through the following three steps. First

the pure components in standard state are mixed isothermally to form an ideal gas mixture. Then each molecule is inflated into a hard sphere with diameterσ. The corresponding Helmholtz energy change is calculated by using the Mansoori-Carnahan-Starling-Leland equation. Finally

the molecules are charged with LJ 12-6 potential to form the real liquid mixture

where the structure is described by an approximated radial distribution function gij(r) = H(r-rij**) + βδ(r-rij*). Henrys constants are then calculated from residual chemical potential. With the use of the same LJ parameters

this model can predict the computer simulation results of Henrys constants quite well. In this respect

this model is superior to the Pierottis theory. For the practical systems

using only one adjustable parameter

the Henrys constants of various gases in C1-C20 alkanes and their isomers

naphthenes

aromatic hydrocarbons and liquid gases can be well correlated over a wide temperature range. The predictions for A△Hs1

△Ss1

and V1 are satisfactory either.