Efficiency of zeolite MCM-22 with different SiO2/Al2O3 molar ratios in gas phase glycerol dehydration to acrolein

• Published in: Microporous and mesoporous materials 2013-11, Vol.181, p.74-82
• Main Authors: Carriço, Camila S., Cruz, Fernanda T., Santos, Maurício B., Pastore, Heloise O., Andrade, Heloysa M.C., Mascarenhas, Artur J.S.
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Colloidal state and disperse state; Dehydration of glycerol; Exact sciences and technology; General and physical chemistry; Ion-exchange; MCM-22; Porous materials; Surface physical chemistry; Sustainable production of acrolein; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zeolites: preparations and properties
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2013.07.020

•MCM-22 zeolite is a highly active and selective catalyst in the gas phase dehydration of glycerol to acrolein.•Glycerol conversion and acrolein selectivity is strongly dependent on the SiO2/Al2O3 molar ratio.•MCM-22 (SiO2/Al2O3=30) has shown the best conversion and selectivity.•Acid and textural properties role an important play in understanding catalytic performance of this zeolite.•MCM-22 catalysts deactivate by coke formation, but can be regenerated by burning in oxidative atmosphere. The gas-phase dehydration of glycerol was conducted over MCM-22 zeolite with different SiO2/Al2O3 molar ratios. MCM-22 zeolites were synthesized and characterized by XRD, FTIR, TG, SEM, EDX, textural analysis by N2 physisorption and NH3-TPD. The MCM-22 zeolites have presented good crystallinity, high surface areas and a decreased amount of acid sites and strength with increasing SiO2/Al2O3 ratio was observed. The glycerol conversion and acrolein selectivity increased with increasing reaction temperature from 280°C to 320°C on MCM-22 (30) catalyst. As long as the concentration of glycerol solution was in the range from 10% to 36.6%, there was no noticeable difference in the glycerol conversion but the acrolein yield increased with water amount in the feed. The glycerol conversion and selectivity to acrolein at 320°C using glycerol feed of 36.6% during 10h of reaction decreased in the following order: MCM-22 (30)>MCM-22 (50)>MCM-22 (80). This result shows that glycerol dehydration to acrolein is strongly dependent on the acid sites density and external surface area of the zeolite MCM-22.