The limited solubility of mineral oils with some chlorinated refrigerants such as R22 and R13 has led to the investigation of synthetic lubricants for refrigeration use. Replacement refrigerants such as R134a and R23 are less soluble in mineral oils but more soluble in a range of synthetic refrigerants. It is essential to obtain data on the solubility of replacement refrigerants in these synthetic lubricants.

In this presentation we present experimental data on vapour-liquid equilibria, liquid-liquid equilibria and liquid-liquid-vapour equilibria for a series of systems of R23, R32 or R134a with n-alkylbenzenes. These equilibria were determined according to the synthetic method using a so-called Cailletet equipment, which can be used in the temperature range –40 C to + 240 C and at pressures up to 250 bar. Depending on the length of the alkyl tail of the n-alkylbenzene type II, IV or III of fluid phase behaviour according to the classification of Van Konynenburg and Scott is found.