The mixed gamma and chi crystalline phase alumina catalyst prepared by the solvothermal method of the mixed solution (toluene and 1-butanol) was investigated for the effect of calcination temperatures and MoO3 modification. The catalysts were characterized by X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and NH3-tempearture programmed desorption (NH3-TPD). The catalytic activity was tested for ethylene production by dehydration reaction of ethanol in gas phase at atmospheric pressure and temperature between 200°C to 400°C. It was found that the calcination temperature and MoO3 loading have an effect on acidity of the catalysts. The increasing in calcination temperature resulted in decreased acidity while the MoO3 loading on the mixed phase alumina catalyst yielded increased acidity especially medium to strong acid. In this study, the catalytic activity of ethanol dehydration to ethylene apparently depends on the medium to strong acid. The mixed phase alumina catalyst calcined at 600°C (C50-600) gave the highest catalytic activity and the MoO3 modified catalysts promoted dehydrogenation reaction.

Thesis (M.Eng.)--Chulalongkorn University, 2013