Peroxodicarbonate as a Green Oxidizer for the Selective Degradation of Kraft Lignin into Vanillin
Michael Zirbes, Tobias Graßl, Rieke Neuber, Siegfried R. Waldvogel
Abstract
Abstract Lignin, the world's largest resource of renewable aromatics, with annually roughly 50 million tons of accruing technical lignin, mainly Kraft lignin, is highly underdeveloped regarding the production of monoaromatics. We demonstrate the oxidative depolymerization of Kraft lignin at 180 °C to produce vanillin 1 in yields up to 6.2 wt % and 92 % referred to the maximum yield gained from the quantification reaction utilizing nitrobenzene. Using peroxodicarbonate (C 2 O 6 2− ) as “green” oxidizer for the degradation, toxic and/or harmful reagents are prevented. Also, the formed waste can serve as makeup chemical in the pulping process. Na 2 C 2 O 6 is synthesized in an ex‐cell electrolysis of aqueous Na 2 CO 3 at BDD anodes, achieving a yield of Na 2 C 2 O 6 with 41 %. At least, the oxidation and degradation of Kraft lignin is analysis via UV/Vis and NMR spectroscopy.