Catalytic Conversion of Biomass-derived Feedstock (HMF) into Value Added Chemicals and Biofuels

HMF (5’-hydroxymethylfurfural) has been identified as a key and versatile biorefining building block for sustainable chemicals, materials, and liquid fuels. The HMF pathway is highly desirable as the conversion of cellulose to HMF can be achieved by chemical, biological, and hydrothermal pathways, and the conversion of HMF to biofuel and a variety of value-added chemicals is also known and generally feasible.

Nevertheless, several challenges and opportunities exist with the HMF chemical pathway. Methods suitable for the industrial scale conversion of cellulose to HMF have not been developed. Furthermore, although the easiest accessible biofuel from HMF (dimethylfuran, DMF) is twice as energy dense as ethanol, it is still only a six carbon (C6) fuel and therefore not as energy dense as higher carbon forms of fuel, such as jet fuel or (bio)diesel. Upgrading of HMF to a higher carbon fuel without the use of additional carbon sources is a particularly difficult challenge for which no industrially acceptable solutions exist.

Dr. Chen’s group has developed a novel catalytic system by which the feedstock chemical HMF can be upgraded into a higher carbon fuel (12C), classified as either kerosene or jet fuel. The system upgrades HMF (a 6C compound) by coupling two HMF molecules together to form a 12C compound (di(hydroxymethyl)furoin, or DHMF), which then undergoes standard hydrogenation/hydrogenolysis processing to form a suitable fuel for use as kerosene or jet fuel. Importantly, this upgrading process stands alone as the only HMF upgrading technology that does not require the 1:1 addition of another compound (as the source of additional carbon).

The upgraded fuel is significantly more energy dense than HMF and can be used as a kerosene or jet fuel. Dr. Chen's lab has also developed methods that further upgrade the fuels to 16C and 21C, as well as techniques that deoxygenate the fuels to form "drop-in" diesel and jet fuel.

This upgrading process offers many advantages that will help biofuel compete with its petroleum equivalent. The nontoxic, organic catalyst upgrades HMF to DHMF at room temperature or under industrially-preferred conditions (60° to 80°C). The conversion catalyst is nontoxic and rapidly upgrades HMF to DHMF (1 to 24 hours, depending on temperature). Yields in excess of 86% have been realized under industry-relevant settings.

This technology also offers the possibility for a one-pot biofuel synthesis (ie., conversion of cellulose to HMF to DHMF without the need for purification between steps). This is still in development.

• Catalytic reaction system that upgrades 6-carbon compounds from biomass to higher value 12-carbon compounds.
• Couples two bio-derived HMF compounds together without requiring addition of other carbon sources (such as petroleum derived small molecules).
• High yield, rapid, non-toxic reaction under industrially preferred conditions (e.g. temperature).
• Additional steps can further upgrade carbon content and remove oxygen atoms from the compounds.
• Results in high carbon content chemical feedstocks for use as jet/diesel fuels or further processing into value added specialty chemicals.