Conclusions
The hydrogenolysis and hydrolysis of lignin in an aqueous alkaline medium must be considered as an oxidative degradation of the lignin macromolecule by hydroxyl radicals. This process takes place even in a reducing medium in the presence of a catalyst. This was shown by a study of the hydrogenolysis process using model compounds. The oxidative processes in lignin are connected with the appearance in the system (lignin or its model) of alkali-induced quinoid structures which, being electron-acceptors, abstract electrons from hydroxyl ions and form hydroxyl radicals. The latter lead to oxidative processes through the the hydroxylation of the system. The correctness of this has been confirmed by studying the composition of the products, which shows the oxidative nature of the hydrogenolysis process.
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Scientific-Research Institute for the Chemistry and Technology of Cotton Cellulose, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 512–517, September–October, 1970.
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Bronovitskii, V.E., Kalinskaya, L.L. Oxidation of lignin in aqueous alkaline solution. Chem Nat Compd 6, 532–535 (1970). https://doi.org/10.1007/BF00563432
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DOI: https://doi.org/10.1007/BF00563432