Ethanol conversion into butadiene over Zr-containing molecular sieves doped with silver†
The synthesis of butadiene-1,3 from ethanol over silver doped (1 wt%) Zr-containing molecular sieves ZrBEA, ZrMCM-41 and ZrO2 supported on silica has been studied. The catalysts were characterized by X-ray diffraction, nitrogen adsorption–desorption, X-ray photoelectron spectroscopy, 29Si MAS NMR, SEM/EDX, TEM and FTIR of adsorbed CD3CN. The activity of the catalysts was found to increase in the following range: Ag/ZrO2/SiO2 < Ag/ZrMCM-41 < Ag/ZrBEA. This activity range correlated with the content of Lewis acid sites in the catalysts determined by FTIR of the adsorbed CD3CN. The best catalyst performance in terms of butadiene yield was observed for ZrBEA (Si/Zr = 100) promoted with silver, which showed butadiene selectivity of 56% at ethanol conversion of 48%.