Synthesis of Butadiene from Formaldehyde and Propylene on Cesium Salts of Silicotungstic Heteropoly Acid

A one-stage gas-phase synthesis of butadiene from formaldehyde and propylene on silica-supported cesium salts of silicotungstic heteropoly acid was realized for the first time. The physicochemical properties of the catalysts were studied by X-ray fluorescence analysis, low-temperature nitrogen adsorption, XRD, SEM, Raman spectroscopy, and NH 3 –TPD. The coke deposits were studied by the TGA–DTA method. Analysis of the catalytic properties showed that an increase in the concentration of cesium atoms in Cs x H 4– x SiW 12 O 40 /SiO 2 ( x = 0–3) has a beneficial effect on the endurance of the catalyst but is accompanied by a decrease in activity and butadiene selectivity. In the case of CsH 3 SiW 12 O 40 /SiO 2 , the butadiene selectivity was 51 mol %.