Nitration Kinetics of Cellulose Fibers Derived from Wood Pulp in Mixed Acids

A model has been developed to describe the reaction kinetics of single cellulose fibers (SCFs) in mixtures of nitric acid, sulfuric acid, and water during the production of highly nitrated nitrocellulose. Experiments were performed to provide insight into factors affecting the rate and extent of reaction for the nitration of wood-pulp-derived cellulose fibers in mixed acids and to provide kinetic data for model evaluation and kinetic parameter estimation. This work provided considerable information regarding the nature of the chemical reaction, and demonstrated that fiber properties do not play a significant role in the reaction kinetics or extent of reaction. This finding is particularly important because it allows for much broader range of wood pulps to be considered for industrial-scale nitration than have historically been used. A semiempirical kinetic model was developed to describe the conversion of cellulose to nitrocellulose as an equilibrium controlled reaction using these results. This kinetic model yielded excellent agreement with experimental results over the entire range of temperatures, fiber types, and reaction times studied.