VAPOR-LIQUID-EQUILIBRIUM MEASUREMENT AND DATA TREATMENT OF N-PROPANOLAND ISOBUTANOL MIXTURE AT ATMOSPHERIC-PRESSURE

The measurement of vapor-liquid equilibrium of n-propanol and isobutan ol binary mixture was carried out in a condensed vapor phase recircula ting still at atmospheric pressure. The experimental data were checked by Herington consistency test and chi-square distribution of statisti cs. The correlation results showed that van Laar equation was the most suitable model to describe the VLE behavior of this mixture and that the absolute correlation coefficient of the pair parameters of model i s near to unity. This says that the model parameters are linearly rela ted to each other and this mixture behaves like a regular solution. Th e experimental points with large residuals were deleted from the data set. The F-distribution test of statistics was then applied to judge w hether the new data-set could better describe phase behavior of mixtur e than the previous set. The statistical chi-square analysis was also applied to determine whether the estimated variance of fit used for ob jective function was reasonable. The data treatment applied in this st udy was different from that applied to isoprene and n-pentane mixture in our previous paper (Lee et al., 1994) where the T-x diagram was use d to delete the experimental points with systematic error.