The critical curves of the four binary systems from CO2-methanol to CO2-1-butanol at temperatures from 300 to 600 K and pressures from 4 to 18 MPa have been calculated. An equation of state that uses a perturbation type containing a repulsion term and a square-well potential attraction term for intermolecular interaction has been used. To use the pairwise combination rule for the square-well molecular interaction potential, three adjustable parameters are required. The experimental critical point data are compared with the values predicted from the equation of state. Good agreement is obtained between the experimental critical pressure-composition data and the calculated values.