Auto-tandem catalytic reductive hydroformylation with continuous multiphase catalyst recycling

Abstract

The production of alcohols from olefin-enriched Fischer–Tropsch products represents a promising route for CO₂-neutral bio-synthetic fuels. Tandem-catalytic systems as alternatives for the conventional two-step production of long-chain alcohols are attractive in terms of energy and resource efficiency. Herein, we present the first rhodium-based catalytic system capable of direct conversion of olefins to alcohols in a biphasic liquid/liquid system. After optimizing the reaction conditions for the biphasic operation, an alcohol selectivity of up to 64% was achieved, while aldehydes and olefin isomers were observed as main by-products. By employing water-soluble alkanolamines, the catalyst is immobilized in a water phase and can be easily separated from the product containing an organic phase with a rhodium loss of as low as 0.1%. After investigation of various reaction parameters, a TON of 128 in batch operation was achieved. Furthermore, the developed catalyst recycling strategy was implemented in a continuously operated miniplant, reaching a TTON for alcohol production of 1236 after 50 hours.