Study on cellulose degradation induced by hydroxyl radical with cellobiose as a model using GC-MS, ReaxFF simulation and DFT computation.

The OH induced cellulose degradation was examined by analyzing the reaction products of Fenton's regents with cellobiose. Many degradation products including C2-C5 compounds such as oxaldehyde, malonaldehyde and 2-hydroxysuccinaldehyde were detected by GCMS analysis. Four reaction pathways for the formation of some degradation products were obtained from ReaxFF kinetics simulation and validated by the DFT quantum chemistry calculation at B3LYP/6-31+g(d,p) level. It was found that the H-abstraction from OH of the glucose unit by OH can cause saccharide ring open and breakage of the glycosidic bond. Pathways 1-4 showed that the glucose unit can react with OH consecutively to produce small molecular products with carbon atoms less than 6. This study indicated that ReaxFF reaction kinetics is a powerful tool for the exploration of the degradation mechanism of cellulose induced by OH at room temperature, which correlated well with the experimental results and was validated by DFT calculation.