Kinetics of the liquid phase dehydration of 1-octanol to di-n-octyl ether on Amberlyst 70

Abstract

The kinetics of the liquid phase dehydration of 1-octanol to di-n-octyl ether (DNOE) over Amberlyst 70 was studied at 413-453K. Mechanistic rate models assuming water and 1-octanol adsorbed on the resin, and the free sites fraction negligible, were selected from 1-octanol dehydration experiments. Next, the influence of DNOE, water and 1,4-dioxane (solvent) concentration was evaluated. DNOE and 1,4-dioxane do not affect significantly the reaction rate, while water inhibits it strongly. Water effect was quantified by splitting the rate constant into a 'true one' and a correction factor related to the fraction of active sites blocked by water. The best kinetic model stemmed from an Eley-Rideal mechanism with water adsorbed onto the resin and DNOE released directly to the liquid phase, with a correction factor for water inhibitory effect based on a Freundlich isotherm-like function; activation energy being 110±5 kJ·mol-1 based in line with literature data on homologous reactions.