Interfacial resistance due to thin films of alcohols and its effect on the rate of evaporation of water

Abstract

Measurements were obtained of the interfacial resistance due to thin films of straight-chain higher alcohols and their effect on the evaporation of water. This was done by passing preheated dry air at a constant rate over water in a beaker. Unlike previous studies both phases were stitted. Four alcohols, dodecyl, myristyl, cetyl, and stearyl, were studied. A large reduction in evaporation was observed when 0.00025 gm. of cetyl alcohol was added to 1 liter of water with gas-liquid interfacial area of 0.2015 sq. ft. A much higher amount of stearyl alcohol, 0.0006 g., was needed for commensurate effect. Resistance due to films of dodecyl and myristyl alcohols was neglibible. For the most part cetyl alcohol is the most effective of those tested. Plots are given of the pseudo mass transfer coefficients and interfacial resistances as a function of the amount of the various alcohols.