Kinetic parameter estimation for methanol dehydration to dimethyl ether over sulfonic and polymeric acid catalysts

Abstract

AbstractBACKGROUNDThe methanol dehydration to dimethyl ether (DME) has received considerable attention in the literature, because of its potential use as a multipurpose fuel. A wide literature of kinetic studies is available for γ‐Al2O3, reference commercial catalyst but only a few authors report a kinetic analysis of attractive and alternative catalysts to γ‐Al2O3 in DME production. The aim of this work was to contribute in this direction, by performing a catalytic test focused on the determination of kinetic parameters for methanol dehydration over sulfonic acid catalysts and polymeric materials.RESULTSThe catalytic and kinetic behavior of these materials for the methanol to DME dehydration reaction has been investigated using a fixed bed reactor at total pressure of 1 bar within a temperature range of 50 to 450 °C. The sulfonated fluoropolymer (Aquivion) exhibited the highest activity and stability for the dehydration reaction at relatively low temperatures at which the γ‐Al2O3 did not display any dehydration activity. The tested catalysts showed good time stability when both methanol and methanol/water mixtures were used as feed reactants. Good agreement was achieved between experimental data and the proposed model.CONCLUSIONThe ‐SO3H groups enhanced the surface acidity and the catalytic performances. The sulfonated perfluorinated polymer (Aquivion) was able to catalyze the methanol/DME conversion at temperatures as low as 90 °C. The selectivity to DME at lower temperatures was 100%. Apparent activation energy for this reaction was experimentally evaluated to 110 KJ/mol and theoretical calculated to 96 KJ/mol: there was a comparable and good agreement with the experimental data. © 2020 Society of Chemical Industry