The study of the deactivation of HY zeolites in the dehydration reaction of glycerol to acrolein has represented a challenge for the design of new catalysts. HY zeolites with SiO2/Al2O3 molar ratios between 3.5 and 80 were studied. The solids were characterized by XRD, N2 physisorption, SEM-EDXS, Raman and UV-vis spectroscopies, infrared spectroscopy of pyridine (FTIR-Py) and catalytic activity tests from 250 °C to 325 °C. It was found that the total amount of acid sites per unit area of catalyst decreased as the SiO2/Al2O3 molar ratio increased from 3.5 to 80, resulting in the decrease in the initial glycerol conversion. The initial acrolein selectivity was promoted with the increase of the Brønsted/Lewis acid sites ratio at any reaction temperature. The deactivation tests showed that the catalyst lifetime depended on the pore structure, improving with the presence of large surface areas as evidenced by the deactivation rate constants. The characterization of the deactivated catalysts by XRD, N2 physisorption and thermogravimetric analysis indicated that the deposition of coke resulted in the total obstruction of micropores and the partial blockage of mesopores. Moreover, the presence of large mesopores and surface areas allowed the amount of coke deposited at the catalyst surface to be reduced.

This study shows the development of a combustion promoter for the oil-refining process called fluid catalytic cracking (FCC). The investigation of a catalyst prepared for the combustion of CO composed of 0.05 wt% Pt supported on SiO2–Al2O3–0.5 wt% W microspheres with high mechanical resistance, promoted with tungsten oxides (WOx) that can inhibit the sintering of Pt, is reported. The addition of WOx in SiO2–Al2O3 inhibited the decrease in the specific area when calcined from 550 °C to 950 °C. SiO2–Al2O3 support in the form of calcined microspheres with average diameters between 70–105 µm were produced by spray drying, using two atomization discs with vanes of different geometry: a straight rectangular blade disc (DAR) and a curved rectangular vanes disc (DAC). The DAR disk produced whole microspheres, while the DAC had hollow and broken microspheres. The microspheres were characterized by XRD, SEM, optical microscopy, N2 physisorption (BET area) and fracture resistance tests. The Pt catalysts were evaluated by TPR, H2 chemisorption and CO combustion. The catalyst of 0.05 wt% Pt/SiO2–Al2O3–0.5 wt% turned out to be the most stable. A thermal stabilization effect was observed at contents lower than 1 wt% W that allowed it to inhibit the sintering of the Pt catalyst.