The depolymerization of lignin into value added chemicals or liquid fuels provide an additional revenue for current polysaccharides based biorefinery processes. Lignin is usually depolymerized into low molecular chemicals via either oxidation or reduction approaches and the conversion processes require the use of expensive metal catalyst such as Nobel metals. Therefore, it is significant to develop sustainable and metal-free catalyst. Graphene oxide (GO) has great potential as sustainable “carbocatalyst” because it contains a variety of functionalities (e.g. hydroxyl, epoxide and carboxylic groups) on its edge and basal plane, which providing powerful oxidizing properties. Herein, we explore capabilities of GO for facilitating oxidation, cleavage and depolymerization of two typical lignin model compounds with <i>β</i>-O-4 linkage at ambient condition. The effects of solvents (e.g. water, THF, DMSO, Ethanol and acetone), the catalyst loading (10 -100 wt. %) as well as temperature (25 -120 <sup>o</sup>C) were studied to achieve the optimized conditions to depolymerize lignin. The results indicated that 100% conversion rate of lignin models to liquid products was achieved at the selected condition.  The main products were identified by GC/MS providing substantial evidences for depicting the reaction mechanisms.

Lignin oxidation depolymerization using graphene oxide as a metal-free catalyst

249th National Meeting (2015)

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