For the multi - phase systems involving CO2

the pressure p can be estimated from the temperature

the weight of CO2

and the volume not occupied by materials other than CO2. An empirical equation is introduced

by which the standard deviation for p calculation is 10.4 % for 11 systems. The accuracy can be improved by considering different solubility of CO2 in various liquid components. By this means

the pressure p can be determined with a standard deviation of 5.39 % . Thus the vapor- liquid equilibrium and kinetic parameters can be obtained without experimental measurements. Further

the copolymerization process of CO2 and propylene oxide can be simulated satisfactorily.