TRANSFORMATION OF ETHANOL INTO 1,3-BUTADIENE OVER MAGNESIUM-OXIDE SILICA CATALYSTS

Contact masses based on MgO and SiO2 and mixtures thereof have been prepared, characterized (temperature-programmed desorption, UV spectroscopy, electron microscopy, energy-dispersive X-ray scanning transmission electron microscopy and X-ray diffraction) and tested in the direct synthesis of 1,3-butadiene from ethanol. The MgO/SiO2 catalyst prepared by wet-kneading the components is distinguished from the mechanical mixture MgO + SiO2 not only by its activity but also by its stability under steady-state conditions. This suggests that in the catalyst there is an interaction between the solids: a synergic effect. The physicochemical measurements confirm significant MgO-structural perturbations, particularly in the catalyst, occasioned by MgO-SiO2 interactions. TPD results indicate an accumulation on the surface of oxygenated C2-species at the steady state, but apparently not oxygenated C4-entities.