1988 Volume 36 Issue 10 Pages 3985-3993
The determination of the molecular volumes of organic substances for which values of specific gravity (d) are not available was investigated. The values of van der Waals volume (VA:Å3/molecule) for aliphatic saturated monocarboxylic acids are closer to those of molecular weight per specific gravity (M/d: cm3/mol) than those of Vw (cm3/mol). The slope of the correlative equation between VA and M/d for organic anionic substances is 1.03, but that between Vw and M/d is 0.62.
The values of VA for organic anionic substances show a good correlation with the absolute ionic mobility (mo) as well as M/d. The values of VA for amino acids and dipeptides also showed a better correlation with mo than the molecular weight (M). Thus, the values of mobility could be better estimated from the molecular volume than the molecular weight.