The oxidation of dimeric lignin model compounds (arylglycerol - β - aryl ethers and phenylcoumarans) by molecular oxygen, catalyzed by [N, N′ - bis(salicylidene) -ethane - 1,2-diaminato] cobalt(II), [Co(salen)], was studied in order to find novel processes for the production of chemicals by degradation of polyphenols contained in waste waters from the pulp and paper industry. All the studied compounds reacted at room temperature in chloroform with high conversion already after 30 minutes; after 48 h the reaction was essentially complete and interesting low molecular weight compounds were isolated with good yields. An EPR investigation of the reaction mixtures indicates the presence of a phenoxy cobalt radical, [CoIII(salen)(RO-)(RO•)], as a reactive intermediate for ROH as phenolic substrate. The electron donor properties of the phenolic substrate and the stability of the phenoxy radical control the yields of the oxidation products
Canevali, C., Morazzoni, F., Orlandi, M., Rindone, B., Scotti, R., Sipila, J., et al. (2001). Oxidative degradation of dimeric lignin model compounds. In D.S. Argyropoulos (a cura di), Oxidative Delignification Chemistry : Fundamentals and Catalysis (pp. 197-210). American Chemical Society..
Oxidative degradation of dimeric lignin model compounds
CANEVALI, CARMEN;MORAZZONI, FRANCA;ORLANDI, MARCO EMILIO;RINDONE, BRUNO;SCOTTI, ROBERTO;
2001
Abstract
The oxidation of dimeric lignin model compounds (arylglycerol - β - aryl ethers and phenylcoumarans) by molecular oxygen, catalyzed by [N, N′ - bis(salicylidene) -ethane - 1,2-diaminato] cobalt(II), [Co(salen)], was studied in order to find novel processes for the production of chemicals by degradation of polyphenols contained in waste waters from the pulp and paper industry. All the studied compounds reacted at room temperature in chloroform with high conversion already after 30 minutes; after 48 h the reaction was essentially complete and interesting low molecular weight compounds were isolated with good yields. An EPR investigation of the reaction mixtures indicates the presence of a phenoxy cobalt radical, [CoIII(salen)(RO-)(RO•)], as a reactive intermediate for ROH as phenolic substrate. The electron donor properties of the phenolic substrate and the stability of the phenoxy radical control the yields of the oxidation products
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