Ethanol conversion into butadiene over Zr-containing molecular sieves doped with silver

Abstract

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%.