Evaluating the catalytic performances of SAPO-34 catalysts for the oxidative dehydrogenation of ethane

Acid silicoaluminophosphate SAPO-34 catalysts with a chabasite-related structure were evaluated for the oxidative dehydrogenation of ethane at 550°-700°C, achieving very interesting catalytic performances (about 70% C₂H₄ selectivity at 45% ethane conversion), which were related to both Lewis and Brønsted acid sites. Ethylene, CO, and CO₂ were detected in all catalytic tests. Traces of methane were formed only at higher conversions, which makes SAPO-34-based catalysts quite distinct from other zeolites. All acid sites were involved in both ethane activation and ethylene formation in contrast to the behavior of ZSM-5, which was more active and selective when alkali metal ions or transition metal ions were present.