Accelerated Cellulose Depolymerization Catalyzed by Paired Metal Chlorides in Ionic Liquid Solvent

Journal Article · Tue Jan 04 04:00:00 EST 2011 · Applied Catalysis. A, General, 391(1-2):436-442

DOI:https://doi.org/10.1016/j.apcata.2010.09.021· OSTI ID:1009733

Su, Yu; Brown, Heather M; Li, Guosheng; Zhou, Xiao Dong; Amonette, James E; Fulton, John L; Camaioni, Donald M; Zhang, Z Conrad

Efficient hydrolytic depolymerization of crystalline cellulose to sugars is a critical step and has been a major barrier for improved economics in the utilization of cellulosic biomass. We report a novel catalytic system involving paired metal chlorides in an ionic liquid that considerably accelerates the rate of cellulose depolymerization under mild conditions. Paired metal chlorides, consisting of CuCl2 (primary metal chloride) and a second metal chloride, such as CrCl2, PdCl2, CrCl3 or FeCl3 in 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) solvent were found to substantially accelerate the hydrolytic cleavage of 1,4-glucosidic bonds as compared to known acid-catalyzed hydrolysis in similar temperature range (80-120°C). In contrast, single metal chlorides with the same total molar loading showed much lower activity under similar conditions. Experimental results illustrate the dramatic effect of the second metal chloride in the paired catalytic system. A combination of characterization techniques, including electron paramagnetic resonance (EPR) spectroscopy, differential scanning calorimetry (DSC), X-ray absorption fine structure (XAFS) spectroscopy, and X-ray absorption near edge structure (XANES) spectroscopy, were used to reveal a preliminary understanding of possible mechanisms involved in the paired CuCl2/PdCl2 catalytic system. Results suggest that the C2-proton of the imidazolium ring may be activated by the paired metal-chloride catalysts.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1009733
• Report Number(s): PNNL-SA-71427; 25449
• Journal Information: Applied Catalysis. A, General, 391(1-2):436-442, Journal Name: Applied Catalysis. A, General, 391(1-2):436-442 Journal Issue: 1-2 Vol. 391; ISSN ACAGE4; ISSN 0926-860X
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
1-alkyl-3-methylimidazolium chloride
1-ethyl-3-methyl-imidazolium chloride
ABSORPTION
BIOMASS
CALORIMETRY
CATALYSTS
CELLULOSE
CHLORIDES
CLEAVAGE
CuCl2
DEPOLYMERIZATION
ECONOMICS
ELECTRON SPIN RESONANCE
Environmental Molecular Sciences Laboratory
FINE STRUCTURE
HYDROLYSIS
Ionic liquid
PdCl2
SACCHARIDES
SOLVENTS
SPECTROSCOPY
catalyst
cellobiose
cellulose
cellulose conversion
depolymerization
glucose
hydrolysis
maltose
paired metal chlorides