Dissolution of microcrystalline cellulose in phosphoric acid--molecular changes and kinetics.
In this study, we aimed to dissolve microcrystalline cellulose (MCC) with phosphoric acid to obtain high-quality fermentable saccharides. MCC was directly dissolved in phosphoric acid (the concentration was 83%) for 10 hours at temperatures of 30, 50, and 70 degrees C. The structural changes of MCC were determined in detail with X-ray powder diffraction, solid-state cross-polarization magic angle spinning (13)C-NMR, and X-ray photoelectron spectroscopy. The kinetics of MCC decrystallization during treatment with phosphoric acid was also compared at 30, 50, and 70 degrees C. With the assumption of first order kinetics, the Arrhenius parameters of K, A(0) and E(a) were calculated. The rate constants of decrystallization reaction (K) were 0.06, 0.17, and 0.12 h(-1) respectively. The pre-exponential factor (A(0)) was 1.2 x 10(6) h(-1), and the activation energy (E(a)) was 42.4 kJ/mol.
Zhang
Junhua
J
Department of Resources Science and Engineering, State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, Guangdong Province, China.
Zhang
Jingqiang
J
Lin
Lu
L
Chen
Tianming
T
Zhang
Jun
J
Liu
Shijie
S
Li
Zhenjiang
Z
Ouyang
Pingkai
P
D002482:Cellulose / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D010756:Phosphoric Acids / Q000737:chemistry*; D013696:Temperature
D010756:Phosphoric Acids; D002482:Cellulose; C030242:phosphoric acid