Preparation and Hydrolysis of Water-Stable Amorphous Cellulose

The facile preparation, aqueous stability, and hydrolysis characteristics of amorphous cellulose regenerated from cellulose solutions using amine/inorganic salt solvents was investigated. Highly crystalline cellulose was dissolved in a mixture of ethylenediamine and NaSCN, KSCN, or NaI at room temperature; subsequent addition of an excess of alcohol, acetone, or acetonitrile immediately precipitated the bulk cellulose in a completely amorphous state. Only a small amount of the amorphous cellulose crystallized during one month in 50 °C water, as revealed by X-ray diffraction and cross-polarization magic angle spinning solid state 13C NMR analyses. The susceptibility of the amorphous cellulose to acid and enzymatic hydrolysis was remarkably enhanced compared with the original highly crystalline cellulose. This simple method for preparing the specific amorphous cellulose, coupled with the high susceptibility of the product cellulose to hydrolysis, suggests that this is a useful process for the production of biofuels and biochemicals from chemical pulp.