| 초록 |
Acid-catalyzed hydrolysis is controlled not only by temperature and acid concentration but also by the physical state of the cellulose. Under low temperature and acid condition the cellulose structure stays in stable crystalline form. Therefore the prevailing reaction mode is endwise hydrolysis. Glucose then becomes the main sugar product. Once the crystalline structure of the cellulose is disrupted, acid molecules can penetrate into the inner layers of the cellulose chains. In support of this hypothesis, we have experimentally verified that a substantial amount of oligomers are formed as reaction intermediates under extremely low acid and high temperature conditions. One of such condition is 210oC, 0.07% H2SO4. Glucose, once it is formed in the hydrolyzate, interacts with acid soluble lignin forming a lignin-carbohydrate complex. On the basis of these findings, a comprehensive kinetic model is proposed. This model is in full compliance with our recent experimental data obtained under broad range of reaction conditions. |
