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Poster Presentation 3-14
Depolymerization of Cellulose to Glucose: The Significance of the Level-off Degree of Polymerization of Cellulose
Roger D’Amour3, Daniel Montané1 and Esteban Chornet2,3
1Universitat Rovira i Virgili, ETSEQ Tarragona, Spain
2Also affiliated with: (a) Enerkem Technologies Inc., 375 Courcelette, Sherbrooke, QC, Canada J1H 3X4; and (b) National Renewable Energy Laboratory, Golden, CO 80401.
3Université de Sherbrooke Sherbrooke, QC Canada, J1K 2R1
E-mail: echornet@courrier.usherb.ca
This paper discusses, based on experimental evidence, the conversion of cellulose to its level-off degree of polymerization (LODP), a structural state at which the cellulose is essentially microcrystalline. It has been found that the depolymerization patterns are similar in water-rich and water-restricted environments. The presence of acid catalyzes the depolymerization, increasing the rate, but it does not alter the conversion patterns which show solubilization of the amorphous cellulose by the time the LODP is reached. Modeling of the depolymerization has been achieved using phenomenological severity markers. The significance of a stepwise depolymerization via a LODP microcrystalline intermediate is that it facilitates subsequent controlled conversion of the intermediate to glucose. Using a combination of decrystallization and mild acid hydrolysis, glucose yields close to stoichiometric with glucose concentrations >5 wt% in the hydrolyzates have been achieved. Converting the cellulose into a LODP intermediate and preparation of the latter as a colloidal suspension or hydrogel may also represent an advantageous way of pretreating the cellulose for enzymatic hydrolysis.
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