Texture and morphology-directed activity of magnesia-silica mixed oxide catalysts of ethanol-to-butadiene reaction

Magnesia-silica mixed oxide catalysts of different texture and morphology were prepared for the ethanol-to-butadiene (ETB) reaction. Magnesia low high specific surface area (SSA) made by thermal decomposition magnesium nitrate. High-SSA MgO was using hard-templating (HT) method. Mesoporous carbon, obtained carbonizing a resorcinol-formaldehyde polymer used as template. The carbon pores saturated Mg(NO3)2 solution calcined then in order to decompose nitrate combust get high-SSA MgO. processes induced latter calcination followed Thermogravimetry-Differential Scanning Calorimetry (TG-DSC) To obtain MgO-SiO2 both magnesia samples wet-kneaded (WK) with silica aerogel structured mesoporous SBA-15 material, having lower higher SSA, respectively. Morphological textural properties these characterized means N2 physisorption, X-ray powder diffraction (XRD), Transmission Electron Microscopy (TEM), photoelectron spectroscopy (XPS), Energy Dispersive Spectroscopy (EDX). Ranking attempted according their acidity basicity, i. e., concentration strength acidic basic sites. Therefore, adsorption interaction molecules, either or character. CO2 NH3 studied Temperature-Programmed Desorption (TPD) method, whereas that pyridine CDCl3 Fourier Transform Infrared (FT-IR). WK changed structure parent oxides, generated Mg-O-Si bonds, acidity, basicity. XPS EDX results showed Mg content from low-SSA than bulk phase, while lower. This demonstrates use template proved be more reactive process bonds. containing always activity butadiene (BD) selectivity corresponding catalyst BD is related subtle acidity-basicity balance. Nevertheless, measured selectivities did not show correlation any parameters characterizing acid-base catalysts. highest yield at 425 °C achieving 75% ethanol conversion level 50% selectivity.