Isobaric vapor-liquid equilibria for methyl esters + butan-2-ol at different pressures

Vapor-liquid measurements for the mixtures of three methyl esters (ethanoate, propanoate, butanoate) and butan-2-ol were obtained at 74.66, 101.32 and 127.99 kPa in a small capacity still. All systems were found to be thermodynamically consistent and the maximum likelihood principle was chosen as the regression technique to determine the parameters of different available equations. Only the mixture methyl butanoate + butan-2-ol presented a minimum azeotrope which shifted toward concentrations richer in alcohol as working pressure increased. Experimental results were compared with prediction by UNIFAC and ASOG methods.