(123h) Competing Kinetics between Electrochemical Reduction of Furfural and Non-Electrochemical Homogeneous Side Reactions

Furfural (FF) is produced at a scale above 250,000 metric tons per year, largely through the Quaker process. This FF can then be used as a solvent but can also be converted to fine chemicals such as furfuryl alcohol (FA), or prospective fuels like 2-methylfuran (MF) through thermochemical processes requiring temperatures above 100°C, high pressures of 10 to 20 bar, and externally-supplied hydrogen gas. FA is used to create furanic resins for industry, and MF has been identified as a potential fuel or fuel additive. Another process is the electrochemical hydrogenation and hydrogenolysis (ECH) of FF which can use renewable electricity to produce FA and MF at room temperature and pressure with required protons being produced in-situ from the electrolyte. FF ECH, when done in acidic media over Cu catalysts can produce FA and MF. The acidic conditions however cause non-electrochemical side reactions that use up both FA and MF. Understanding the competition between the reactions can assist in achieving higher yields of desired products.

We found that the ECH reactions to FA and MF were both dependent on the concentration of furfural until concentrations of 60mM at which a plateau was seen, following a Langmuirian trend. Homogeneous side reactions occurred in solutions of pH 0 and 1 in which both FA and MF were lost. The homogeneous side reactions were concentration dependent in FA and MF and impacted the performance of ECH. By deriving kinetic relations for the desired and non-desired reactions, we showed that the as the conversion continued to increase, the yield in a batch reactor reached a peak before dropping (Figure 1). The kinetic relations from this work can assist in modeling of reactors to check for the impact of acidic conditions and impact onto the desired yield.