Viscosities and densities of the methyl esters of some n-alkanoic acids

The densities and viscosities of the methyl esters of hexanoic, heptanoic, octanoic, decanoic and dodecanoic acids were determined at temperatures ranging from 10 to 80°C at 5°C intervals. The densities of the methyl esters vary linearly with temperature. When fluidities were plotted against molal volumes of the esters, smooth curves were obtained. Intrinsic volumes were determined by extrapolation to zero fluidity. Based upon Hildebrand's equation, the B values, which represent a measure of the molecules resisting transport of momentum, were calculated for each ester and found to be exponentially related to the temperatures. A modified equation relating the fluidity with temperature was formulated. Excellent agreement was obtained between calculated and experimental fluidities.