Hydrochloric Acid-Catalyzed Levulinic Acid Formation from Cellulose: Data and Kinetic Model to Maximize Yields

In this study, the kinetics of the acid catalyzed hydrolysis of microcrystalline cellulose (Avicel PH101) to levulinic (LA) and formic (FA) acids was investigated in a batch reactor over the following range of conditions: 160-200 degrees C, hydrochloric acid concentrations of 0.309-0.927 M (11.3-33.8 g/l), cellulose concentrations of 49.8-149 mM (8.06-24.1 g/l), and residence times of 0-50 min. The maximum LA yield of around 60% of theoretical was achieved for an initial cellulose concentration of 99.6 mM, acid concentration 0.927 M, and 180-200 degrees C. A mathematical model and its analytical solution were developed to predict conversion of cellulose to LA and FA through glucose and hydroxymethyl-2-furfural based on an irreversible pseudo-first order reaction. Rate analysis of each reaction indicated that the rate-controlling step shifted from LA formation initially to HMF formation later. (C) 2011 American Institute of Chemical Engineers AIChE J, 58: 236-246, 2012