Effects of crystallinity on dilute acid hydrolysis of cellulose by cellulose ball-milling study.

The dilute acid (0.05 M H2SO4) hydrolysis at 175 oC of samples comprising varying fractions of crystalline (I) and amorphous cellulose was studied. The amorphous content, based on XRD and NMR, and the product (glucose) yield, based on HPLC, increased by as much as a factor of three upon ball milling. These results are interpreted in terms of a model involving mechanical disruption of crystallinity by breaking hydrogen bonds in Icellulose, opening up the structure and making more -1,4 glycosidic bonds readily accessible to the dilute acid. However, in parallel with hydrolysis to form liquid phase products, there are reactions of amorphous cellulose that form solid degradation products.