Mechanochemistry Unlocks direct cellulose conversion to 5-Hydroxymethylfurfural.

Area of Science:

• Green Chemistry and Biomass Valorization
• Materials Science and Engineering
• Catalysis and Reaction Engineering

Background:

• Producing 5-hydroxymethylfurfural (HMF) from cellulose is difficult due to cellulose's resistance to breakdown and product degradation under acidic conditions.
• Existing methods often require harsh conditions or multiple steps, limiting efficiency and scalability for this pivotal bio-based platform chemical.

Purpose of the Study:

• To develop an efficient, one-pot strategy for converting cellulose into HMF.
• To activate cellulosic feedstocks using a combination of Lewis acidity and mechanical force.
• To establish a potentially scalable route for biomass valorization into HMF.

Main Methods:

• An AlCl3-assisted mechanochemical strategy was employed, combining Lewis acid catalysis with ball-milling mechanical force.
• Cellulose activation involved disrupting hydrogen bonds and cleaving glycosidic linkages, reducing crystallinity and polymerization degree.
• The pretreated cellulose was directly converted to HMF, with optimization through controlled HCl addition to balance Brønsted/Lewis acidity.

Main Results:

• The synergistic AlCl3-mechanochemical treatment significantly enhanced cellulose reactivity.
• Direct conversion of pretreated cellulose yielded up to 46.8% HMF, with yields increasing to 62.8% after HCl optimization.
• The method demonstrated broad applicability across diverse lignocellulosic biomass resources (waste paper, corncob, bamboo, corn straw).

Conclusions:

• The AlCl3-assisted mechanochemical strategy provides an efficient and potentially scalable route for cellulose and lignocellulosic biomass conversion to HMF.
• This approach overcomes key challenges in cellulose activation and HMF production, offering a promising pathway for bio-based chemical synthesis.
• The developed pretreatment method significantly improves the chemical reactivity of recalcitrant biomass, enabling high yields of valuable platform chemicals.