Deactivation study of catalysts Amberlyst(tm) 35 and Purolite CT® 275 by acetonitrile

Abstract

Nowadays tertiary alkyl ethers are widely employed as high performance components for gasoline blending. This is because ethers enhance gasoline properties, such as octane rating. Ethers result essential to fulfil current environmental legislation, especially in more developed countries. For this reason etherification reactions have today an increasing interest for petrochemical industry. The simultaneous liquid-phase production of ethyl tert-butyl ether (ETBE) and tertamyl ethyl ether (TAEE) is the reaction system studied in the present work. These ethers are usually formed from ethanol (as common reactant) and isobutene (IB) for ETBE and isoamylenes (IA) for TAEE. These olefins are part of the C4 and C5 cuts from Fluid Catalytic Cracking (FCC) or Stream Cracking units (SC). Usual impurities from these cuts are basic compounds such as acetonitrile (ACN) and amines. ACN is present in very low concentration but even at such low concentrations is the main cause of acid catalyst deactivation. Diffuse deactivation, means of acid sites neutralization, is one of the most important drawbacks that affect the catalyst lifespan of industrial reactors. For the mentioned causes, it is therefore interesting to study the effect of the presence of ACN in the reactant streams on the catalysts used for etherification reactions. The catalysts used in this study are AmberlystTM 35 (A35) and Purolite CT® 275 (CT275), both widely employed in industrial etherification units.