Levulinic acid (LA) is a top building block obtained from biomass-derived sugars. Advances in conversion of cellulose-derived biomass to date have resulted in selective yields of levulinic acid of up to about 80% at a production cost of about 5 cents (US) per pound. Significant R&D efforts have been extended to develop chemicals and fuels that originate from LA. LA-derived chemicals are applied in the chemical industry as solvents and plasticizers, in the food industry, and in other applications. However, current methods for upgrading biomass-derived sugars including hexoses (6-carbon sugars) and pentoses (5-carbon sugars) are limited by a lack of robust catalysts, high operating costs, and low yields.

PNNL scientists have developed a method for decarboxylation of levulinic acid to generate ketones. The PNNL-developed method provides the direct conversion of levulinic acid to methyl ethyl ketone (MEK) via decarboxylation.  This highly desired conversion proceeds over a copper (Cu) catalyst at 450 degrees C.  No cyclic products or intermediates (e.g., lactones) are produced, and no reducing gas (H2) is used.  Thus, no catalyst coking or deactivation is observed.

Complete conversion of the levulinic acid is obtained, with MEK formed at 35% selectivity and acetone at 5%.  MEK and acetone may be distilled and used or sold as commodity chemicals, or the reaction products can be readily converted to transportation.