Optimization of separation on the basis of UNIFAC parameters and evaluation of the composition of the stationary phase in gas-liquid chromatography

An algorithm for the optimisation of separation in gas-liquid chromatography based on varying the composition of the stationary phase and the column temperature is presented using the critical parameter R-S greater than or equal to 0.75 (SigmaR(S) double right arrow max). The stationary phase composition, on the basis of retention parameters expressed in terms of vapour pressure and activity coefficient has been derived. Determination of the composition of the stationary liquid was carried out by defining the nature of solute-solvent interactions using group additive value contributions to the activity coefficients. Predicting values on experimentally determined parameters reduced calculation errors by a factor 2 to 3. The results of the analysis of liquid products from the synthesis of vinyl chloride and chloroprene from acetylene and HCl are presented. The results reveal the mechanism of the reaction and allow optimum conditions to be obtained.