Vapor-Liquid Equilibrium Study in the Alcohol Binary Solutions using the Cluster Model

Abstract

The vapor-liquid equilibrium was analyzed for infinitely miscible binary solutions of alcohols exhibiting positive deviations from the Raoult’s law on the basis of the cluster model. The considered substances were by-products of the Fischer --- Tropsch process and various additives to the biofuel. Cluster model equation was provided to describe concentration dependences of vapor pressure over the solution on composition of the liquid phase. The model applicability included non-electrolyte solutions, which deviation from ideality was caused by preferential association of one of the solution components. The model equations parameters were the mathematical expectations of the associates’ distribution in standard state and dispersion of the association number. It is shown that the model equations adequately describe experimental data on vapor pressure for mixtures of various aliphatic alcohols with diethyl carbonate and ketones. For mixtures of hydrocarbons with pentanol isomers, the previously formalized method for simulating vapor pressure along concentration dependences of the mixture excess molar characteristics on the liquid phase composition was applied. It was established that solutions obtained by various methods are in good agreement with each other and adequately describe concentration dependences of the vapor pressure on composition of the liquid phase