Catalytic upgrading of fermentation-derived organic acids

The production of organic acids in low-cost, high-efficiency fermentation processes makes available a new route to chemical production from biomass. Because of their multiple functional groups and high reactivity, organic acids can undergo a variety of reactions that are effectively catalyzed by inorganic heterogeneous or homogeneous catalysts. Lactic acid and succinic acid, in particular, are approaching large-scale production via fermentation and show excellent promise as feedstocks for catalytic conversion routes such as hydrogenation, dehydration, or condensation. A number of catalytic conversion pathways of organic acids are potentially competitive with petroleum-based routes in the current economic environment, particularly when integrated into existing biomass/crop processing schemes. This article reviews some of the key reaction pathways available using fermentation-derived organic acids as feedstocks and presents recent results from the authors' lab on succinate hydrogenation to 1,4-butanediol and tetrahydrofuran. By a judicious choice of support properties and reaction conditions, it is possible to achieve yields of either of these two products in excess of 80%.