Accelerating Selective Oxidation of Biomass-Based Hydroxyl Compounds with Hydrogen Bond Acceptors

Area of Science:

• Catalysis
• Green Chemistry
• Biomass Valorization

Background:

• Hydrogen-bonding causes self-association in biomass-derived hydroxyl compounds, hindering high-concentration valorization.
• Optimizing oxidative reactivity of concentrated hydroxyl compounds using noncovalent medium effects requires further understanding.

Purpose of the Study:

• To elucidate the role of deaggregation in enhancing the aerobic oxidation of biomass-based aromatic alcohols.
• To investigate the use of hydrogen bond acceptors to improve the reactivity and selectivity of concentrated hydroxyl compounds.

Main Methods:

• Aerobic oxidation of neat 5-hydroxymethylfurfural (HMF) using a vanadium-based catalyst.
• Employing N,N-dimethylformamide (DMF) as a hydrogen bond acceptor to deaggregate hydroxyl groups.
• Varying the concentration of DMF to study its effect on reaction kinetics and selectivity.

Main Results:

• Deaggregation of hydroxyl groups with a catalytic amount (25 mol %) of DMF significantly enhances HMF oxidation reactivity (>7-fold increase).
• The optimized conditions yield corresponding aldehydes with excellent selectivity.
• Excessive DMF concentrations lead to deactivation, highlighting the importance of controlled deaggregation.

Conclusions:

• Deaggregation of hydroxyl groups via hydrogen bond acceptors is crucial for improving the aerobic oxidation of concentrated biomass-derived aromatic alcohols.
• This strategy offers a pathway for efficient valorization of biomass compounds, contrasting with reaction deactivation observed at high additive concentrations.