Isobaric vapor-liquid equilibrium (VLE) data (x-y-T-P) were measured for binary methanol- and benzene-morpholine systems in a Swietoslawski type ebulliometric still at 101.325 kPa. The data were correlated with liquid activity coefficient models by using a parameter estimation method based on the maximum-likelihood principle, the observed vapor phase compositions (Y(ex)) being intentionally excluded from the data reduction scheme.