Vapor-liquid equilibrium (VLE) data were measured for the nine ketone/alkane pairs comprising, one of 2-heptanone, 3-heptanone, and 4-heptanone with n-octane, n-nonane), and n-decane at an absolute pressure of 40 kPa. Thermodynamic consistency of the data was checked using the Wisniak L/W and McDermott-Ellis consistency tests. Azeotropic points were observed in all nine Systems at the considered operating pressure and the data were correlated with the NRTL activity coefficient Model. The data. Showed that the location of the dipolar carbonyl group influences the binary phase behavior of ketone structural isomers with a common second component