A DISCUSSION OF THE EXCESS GIBBS ENERGY OF LIQUID MIXTURES BASED ON THE LOCAL COMPOSITION

Abstract

Based on local composition, the Wilson equation, NRTL equation and Bruin equation are discussed. A new two-parameter equation
g^E/RT=x₁x₂{W₁₂/x₂+x₁exp(-W₁₂)+W₂₁/x₁+x₂exp(-W₂₁)}
is proposed. This equation maybe applied to most systems, as can the three-parameter NRTL equation, though it has the limited use to the systems having the large negative deviation from Raoult''s law. This equation is tested and compared with other equations including van Laar equation for five binary and two ternary systems and good results are obtained.