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

BACKGROUND: The 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. RESULTS: The 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. CONCLUSION: The -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.