Surprised by selectivity

Abstract

Lower olefins, particularly ethylene (C2H4), propylene (C3H6), and butylene (C4H8), are important intermediates in the manufacture of products such as plastics, solvents, paints, and medicines. They are produced worldwide in amounts exceeding 200 million tons per year (see the photo) (1), mostly from crude oil. More recent approaches use methanol or synthesis gas (syngas; a mixture of carbon monoxide and hydrogen) as feedstocks, but capital investments are high and/or selectivities to lower olefins limited. A bifunctional catalyst reported by Jiao et al. on page 1065 of this issue (2) enables the direct conversion of synthesis gas to lower olefins with a surprisingly high selectivity.