Acid SAPO-34 Catalysts for Oxidative Dehydrogenation of Ethane

Acid SAPO-34-based microporous catalysts with chabasite structure have been tested for the oxidative dehydrogenation of ethane in the temperature range 550–700°C. Pure acid and La/Na-containing samples were monitored and very interesting catalytic performances were achieved at 550–700°C (75–60% C2H4 selectivity and 5–30% ethane conversion) with respect to those reported for both acid zeolites and metal oxides. These performances correlated to the Brønsted acidity probed by FTIR spectroscopy and temperature-programmed desorption of NH3. The number of Brønsted acid sites located at the bridging hydroxyls (3626–3600 cm−1) in acidic SAPO-34 was higher than in La- and Na-containing samples, which showed also a larger amount of P–OH at framework defects. Lewis acidity induced by the presence of La and Na ions also influenced the reactivity of the SAPO-34-based catalysts.