Formation of HNCO during catalytic reduction of NO x with olefins over Cu/ZSM-5

Abstract

Gaseous cyanic acid (HNCO) is formed in the temperature range 513–666 K during the selective catalytic reduction of NO_x with olefins (ethene, propene) over Cu/ZSM-5 under dry conditions, whereas with ammonia no HNCO is observed in the presence of water in the same temperature range; other by-products are hydrogen cyanide, formaldehyde, ethene (with propene as reducing agent), methane and 2-methylpent-1-ene.