An association model applicable to calculating the solubilities of low-volatile substances in supercritical fluids was derived and compared with experimental data available in the literature

showing good agreement over wide ranges of temperatures and pressures: 1.01≤Tr≤1.23; 0.96≤Pr≤9.66 On the basis of this model

the solvability of supercritical fluids and its changing tendency with other variables over the range likely to be encountered in supercritical fluid extraction were discussed. Some deductions derived from the model showed good agreement with experimental results.