Equilibrium film pressure of the monolayers on water of n-long-chain alcohols and n-long-chain alkoxy-ethanols

Abstract

The equilibrium film pressure, ?e, on water surface of the two homologous series, n-long chain alcohols, C_n-OH, and the corresponding n-alkoxy-ethanols, C_nOC₂H₄OH (n = 14, 16, 18, 20, 22), was measured in the temperature range of 15°C. to 35°C. In the case of the n-alcohols, π_e increased with the decrease in chain length and with increase in temperature, but in the case of n-alkoxy-ethanols there was no such systematic behavior and, for C₁₄- and C₁₆-OC₂H₄OH, dπ_e/dT was found to be negative. Further, the π_e for alkoxy-ethanols was found to be considerably higher than for the n-alcohols. A number of thermodynamic properties related to spreading were calculated from the variation of π_e with the temperature.