Oxidative destruction of dichloromethane over protonic zeolites

• Published in: AIChE journal Vol. 49; no. 2; pp. 496 - 504
• Main Authors: López-Fonseca, R., Cibrián, S., Gutiérrez-Ortiz, J. I., Gutiérrez-Ortiz, M. A., González-Velasco, J. R.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.02.2003; Wiley Subscription Services; American Institute of Chemical Engineers
• Subjects: Applied sciences; Atmospheric pollution; Catalysis; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; General processes of purification and dust removal; Pollution; Prevention and purification methods; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Conversion rate; Thermooxidative degradation; Volatile organic compound; Selectivity; Chemical degradation; Zeolite; Experimental study; Bronsted site; Molecular sieve; Characterization; Heterogeneous catalysis; Catalytic combustion; Chlorine Organic compounds; Chlorocarbon; Mordenite; Dichloromethane; Physicochemical purification; Oxidation; Kinetics; Catalyst activity; Flue gas purification; Catalyst
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.690490219

Various protonic zeolites (H‐Y, H‐ZSM‐5, and H‐MOR) were tested for the total combustion of dichloromethane (DCM) as a model reaction for the catalytic destruction of chlorinated organic pollutants. The order of catalytic activity decreased in the following order: H‐MOR > H‐ZSM‐5 > H‐Y. Strong Brønsted acidity played a determining role in controlling the active catalytic behavior as revealed by TPD of ammonia and IR measurements of adsorbed pyridine. DCM oxidative decomposition gave rise to CO and HCl as main products along with small amounts of CO2 and Cl2. In addition, methyl chloride was detected as a reaction intermediate between 250 and 500°C. The presence of water in the feed stream led to an inhibition of the zeolite activity and resulted in a noticeable change in the reaction product distribution. Water effectively promoted the selectivity toward environmentally desirable reaction products, that is, HCl and CO2, and completely suppressed the formation of methyl chloride.