Heterogeneous aspects of acid hydrolysis of α-cellulose
- 273 Downloads
Hydrolysis of α-cellulose by H2SO4 is a heterogeneous reaction. As such the reaction is influenced by physical factors. The hydrolysis reaction is therefore controlled not only by the reaction conditions (acid concentration and temperature) but also by the physical state of the cellulose. As evidence of this, the reaction rates measured at the high-temperature region (above 200°C) exhibited a sudden change in apparent activation energy at a certain temperature, deviating from Arrhenius law. Furthermore, α-cellulose, once it was dissolved into concentrated H2SO4 and reprecipitated, showed a reaction rate two orders of magnitude higher than that of untreated cellulose, about the same magnitude as cornstarch. The α-cellulose when treated with a varying level of H2SO4 underwent an abrupt change in physical structure (fibrous form to gelatinous form) at about 65% H2SO4. The sudden shift of physical structure and reaction pattern in response to acid concentration and temperature indicates that the main factor causing the change in cellulose structure is disruption of hydrogen bonding. Finding effective means of disrupting hydrogen bonding before or during the hydrolysis reaction may lead to a novel biomass saccharification process.
Index EntriesAcid hydrolysis cellulose hydrogen bonding kinetics crystallinity
Unable to display preview. Download preview PDF.
- 1.Fengel, D. and Wegener, G. (1984), Wood Chemistry, Ultrastructure, Reactions, Walter de Gruyter, Berlin, Germany.Google Scholar
- 2.Shafizadeh, F. (1963), TAPPI J. 46, 381–383.Google Scholar
- 4.Harris, J. F. (1975), Appl. Polym. Symp. 28, 131–144.Google Scholar
- 5.Philipp, B., Jacopian, V., Loth, F., Hirte, W. and Schulz, G. (1979), in Hydrolysis of Cellulose: Mechanisms of Enzymatic and Acid Catalysis, Advances in Chemistry Series No. 181, Brown, Jr. R. D. and Jurasek, L., eds., American Chemical Society, Washington, DC, pp. 127–143.Google Scholar
- 7.Springer, E. L. (1966), Tappi 49, 102–106.Google Scholar
- 10.Millett, M. A., Effland, M. J., and Caulfield, D. F. (1979), in Hydrolysis of Cellulose: Mechanisms of Enzymatic and Acid Catalysis, Advances in Chemistry Series No. 181, Brown, Jr R. D. and Jurasek, L., eds., American Chemical Society, Washington, DC, pp. 71–89.Google Scholar
- 12.(1995) NREL Chemical Analysis and Testing Standard Procedure, No. 001-014, National Renewable Energy Laboratories, Golden, CO.Google Scholar
- 13.Sasaki, M., Kabyemela, B., Adschiri, T, Malaluan, R., Hirose, S., Takeda, N., and Arai, K. (1997), unpublished poster presentation in Fourth International Symposium on Supercritical Fluids, Sendai, Japan.Google Scholar