ESTIMATION OF ENTROPY OF VAPORIZATION - EFFECT OF CHAIN-LENGTH

The entropy of vaporization of organic non-hydrogen bonding compounds can be estimated by using the following modifications of Trouton's rule: (1) for rigid molecules, ΔSv = 20 cal/deg·mole; (2) for long chain derivatives of such molecules, ΔSv = 20 + 0.16(n-5) cal/deg·mole, where n is the number of flexible links in the chain, and n > 5. These simple rules provide a good estimation for the entropy of vaporization which is sufficiently accurate to obtain reasonable estimations of vapor pressure. © 1990.