Hydrolysis of microcrystalline cellulose using functionalized Bronsted acidic ionic liquids - A comparative study

Area of Science:

• Green Chemistry
• Biomass Conversion
• Catalysis

Background:

• Increasing demand for platform chemicals necessitates sustainable cellulose conversion methods.
• Ionic liquids offer tunable properties for efficient biomass hydrolysis.
• Microcrystalline cellulose is a key renewable feedstock.

Purpose of the Study:

• To investigate the efficacy of various functionalized ionic liquids for microcrystalline cellulose hydrolysis.
• To optimize reaction conditions including temperature, time, acidity, and catalyst loading.
• To correlate experimental findings with theoretical calculations.

Main Methods:

• Hydrolysis of microcrystalline cellulose using SO3H, COOH, and OH functionalized imidazole-based ionic liquids in [BMIM]Cl solvent.
• Systematic variation of temperature, time, ionic liquid acidity, and catalyst loading.
• UV-vis spectroscopy for Hammett function determination and Density Functional Theory (DFT) calculations for structural optimization.

Main Results:

• The SO3H functionalized ionic liquid achieved a maximum yield of 85% for total reducing sugars (TRS) under optimal conditions (100°C, 90 min, 0.2g catalyst).
• Acidity trend of ionic liquids determined as SO3H > COOH > OH.
• Experimental results were validated by DFT calculations.

Conclusions:

• SO3H functionalized ionic liquids are highly effective catalysts for cellulose hydrolysis.
• Optimized reaction conditions significantly enhance platform chemical precursor yields.
• The study provides a foundation for scalable and sustainable cellulose valorization.