A comparison of many different mixing rules in a cubic equation of state for 1-alkanol + n-alkane mixtures

Abstract

Abstract Different density dependent and density independent mixing rules have been tested for a modified Redlich-Kwong EOS. The attractive parameter of the pure component is considered to be temperature dependent, and adjustable parameters in the attractive term are fitted to achieve a good agreement between experimental and calculated vapour pressure data for the pure compounds. The general form of the considered mixing rule has eight adjustable parameters, and it is possible to choose an arbitrary subset of the adjustable parameters in fitting experimental VLE data. Mixing rules with one, two, three or four parameters were tested for a number of 1-alkanol + n-alkane systems. For such systems false liquid-liquid splits occur. They may be avoided by including liquid-liquid critical points into the fit or by a constrained parameter fit.