The rate of evaporation of droplets. III. Vapour pressures and rates of evaporation of straight-chain paraffin hydrocarbons

Abstract

The vapour pressures, latent heats of vaporization and fusion and diffusion coefficients of the vapours in air, have been determined at 15 to 40 degrees C, by a combination of Knudsen's vapour-pressure technique and studies on the rate of evaporation of drops and solid beads, for n-C$_{16}$H$_{34}$, n-C$_{17}$H$_{36}$ and n-C$_{18}$H$_{38}$. The rates of evaporation of drops and solid beads agree with the previously published theory, and lead to a value of unity for the evaporation coefficient. A new experimental method is described for determining the self-cooling on evaporation of a drop. The bearing of the results on the size and shape of hydrocarbon molecules is discussed.