VAPOR-LIQUID-EQUILIBRIA OF BINARY-MIXTURES OF ALKANOLS WITH ALKANES FROM ATMOSPHERIC-PRESSURE TO THE CRITICAL-POINT

A reformulated version of the Wong-Sandler mixing rule and the Peng-Ro binson equation of state are used for the correlation and prediction o f the vapor-liquid equilibrium of several alkanol + alkane binary syst ems. The description of these mixtures provides a stringent test since cubic equations of state with conventional mixing rules usually predi ct false liquid-liquid splits for such systems. For all systems, the m odel parameters used were fit to data on the lowest temperature isothe rm and then higher-temperature isotherms were successfully predicted w ith those parameters. False phase splitting was avoided by using a con strained parameter fit. For highly asymmetric (in size) alkanol + alka ne binaries four parameters were necessary for an accurate representat ion of the data, while for less asymmetric alkanol + alkane binaries o nly two parameters were used.