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° 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.