Direct synthesis of extra-heavy olefins from carbon monoxide and water

Extra-heavy olefins (C(12+)(=)), feedstocks to synthesize a wide range of value-added products, are conventionally generated from fossil resources via energy-intensive wax cracking or multi-step processes. Fischer-Tropsch synthesis with sustainably obtained syngas as feed-in provides a potential way to produce C(12+)(=), though there is a trade-off between enhancing C-C coupling and suppressing further hydrogenation of olefins. Herein, we achieve selective production of C(12+)(=) via the overall conversion of CO and water, denoted as Kölbel-Engelhardt synthesis (KES), in polyethylene glycol (PEG) over a mixture of Pt/Mo(2)N and Ru particles. KES provides a continuously high CO/H(2) ratio, thermodynamically favoring chain propagation and olefin formation. PEG serves as a selective extraction agent to hinder hydrogenation of olefins. Under an optimal condition, the yield ratio of CO(2) to hydrocarbons reaches the theoretical minimum, and the C(12+)(=) yield reaches its maximum of 1.79 mmol with a selectivity (among hydrocarbons) of as high as 40.4%.