Thermally stable ion-exchange resins as catalysts for the liquid-phase dehydration of 1-pentanol to di-n-pentyl ether (DNPE)

Conversion, selectivity, yield, and kinetics of the liquid-phase dehydration of I-pentanol to di-n-pentyl ether (DNPE) were determined at 403-463 K on a recently developed sulfonated resin, Amberlyst 70, which is thermally stable up to 473 K. The behavior of Amberlyst 70 was compared with that of Nafion resin NR50, an H-Beta zeolite, and styrene-divinylbenzene resins stable up to 423 K (i.e., Amberlyst 36 and CTL 224). Amberlyst 70 was found to be the most suitable catalyst for this application, showing the highest conversion and yield, with a selectivity to DNPE >= 93%, despite the fact that NR50 showed the highest selectivity to ether at 423-463 K. The kinetic study reveals that a model stemming from an ER mechanism in which I-pentanol from the liquid phase reacts with I-pentanol adsorbed on a single center to give ether adsorbed on a single site represents data on each catalyst. The activation energy was computed to be in the range 110-120 kJ/mol on all the catalysts. (c) 2006 Elsevier Inc. All rights reserved.