Lignin is a three-dimensional organic biopolymer present in large scale in the secondary cell walls of vascular plants primarily mixed with cellulose and hemicellulose. It is composed of phenylpropanoid units which are linked by ether and carbon-carbon bonds. Its structural determination is very complex because lignin does not have any regular monomeric sequence. Nowadays, lignin is considered as a potential alternative source for different types of value-added chemicals and for renewable energy. Therefore, it is necessary to understand the comprehensive structure and macromolecular features of lignin. Numerous degradation methods are used to reveal the comprehensive structure of lignin. Cupric oxide is a mild oxidant, showed better oxidative degradation than others, mainly breaking down the ether linkages between the monomeric units, keeping the aromatic ring intact producing the substituent phenolic monomers which comprise lignin. In our present study, the reaction was carried out at 150±2 °C at 1.5, 2, 2.5 hours followed by GC-MS analysis, to determine the optimized reaction time. Lignin produced four different moieties guaiacol, vanillin, acetovanillone and homovanillic acid in each condition. The quantitative results showed that the production of guaiacol remain same with the increase of reaction time. On the other hand, the vanillin production increased with the increase of reaction time and production of acetovanillone and homovanillic acid increased from 1.5 hours to 2 hours but decreased when the reaction time increased from 2 hours to 2.5 hours.

Cupric oxide oxidation of lignin: Effects of reaction time

2019 Spring National Meeting

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