PRODUCTION OF DIETHYLETHER BY CATALYTIC DEHYDRATION OF ETHANOL OVER HYDROXYAPATITE/ALUMINA-SILICA CATALYSTS

Abstract

Hydroxyapatite and alumina-silica catalysts prepared by physical and chemical methods were examined in ethanol dehydration reaction for catalytic activity and selectivity. The catalysts prepared by physical mixing method were obtained by varying weight ratios of hydroxyapatite to alumina-silica (0-100 wt%). In chemical mixing method part, the hydroxyapatite and alumina-silica catalysts were prepared by sol-gel and co-precipitation methods. All catalysts were characterized by X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR) Analysis, Raman spectroscopy, NH3-tempearture programmed desorption (NH3-TPD) and thermal gravimetric analysis (TGA). The catalytic activity was determined in dehydration reaction of ethanol in order to produce diethylether (DEE). The reaction was run in gas phase at atmospheric pressure and temperature range from 200 to 400oC. For DEE production and catalytic performance, time-on-stream was performed at suitable condition during 10 hours. From the result, it was found that the optimal ratio of hydroxyapatite to alumina-silica catalyst was 4 to 6 by weight % for the physical mixing. The catalyst exhibited the highest DEE yield as 32% at 350oC. The catalyst prepared by co-precipitation method presented the highest DEE yield at 300oC as 24%.