PRODUCTIVE AND PARASITIC PATHWAYS IN DILUTE ACID-CATALYZED HYDROLYSIS OF CELLULOSE

Cellulose hydrolysis experiments were conducted in a percolating reactor at 34.5 MPa. A glucose yield of 71% of the theoretical maximum was obtained at 215-degrees-C with 0.05% by weight of sulfuric acid in the percolating solution. The classical model of glucose formation from cellulose followed by secondary sugar degradation did not describe the reaction chemistry under these conditions. A parasitic pathway which leads to the formation of nonhydrolyzable oligomer was discovered in the absence of acid. In the presence of acid, kinetic modeling of the measured, temperature-dependent rates of glucose evolution indicates that an acid-catalyzed parasitic pathway operates in competition with the glucose production pathway. No chemical changes were detected in the solid phase during the course of reaction.