Cellulose degradation in the reaction system O-2/heteropolyanions of series [PMo(12-n)VnO40]((3+n)-)

resumo

The degradation reactions of cellulose under conditions of dioxygen oxidation in acidic aqueous and organic solvent-water medium in the presence of molybdovanadophosphate heteropolyanions of series [PMo(12-n)VnO40]((3+n)-) have been investigated. The medium acidity and the heteropolyanions action were found to be the factors causing cellulose chain scission by solvolytic and oxidative degradation reactions, respectively. The cellulose oxidative depolymerisation was associated mainly with the action of VO2+ ions released from heteropolyanions via their partial dissociation under acidic conditions. The scheme reflecting the main pathways of cellulose degradation in the reaction system dioxygen/heteropolyanions is proposed. The effect of the medium ionic strength on cellulose depolymerisation is discussed in the context of possibilities to minimise the negative action of medium acidity and of VO2+ ions on cellulose. (C) 2000 Elsevier Science Ltd. All rights reserved.

palavras-chave

ENVIRONMENTALLY BENIGN TECHNOLOGY; KRAFT PULP; HETEROPOLY ACIDS; WOOD PULP; DELIGNIFICATION; OXYGEN; MECHANISM; OXIDATION; CATALYSIS; CHEMISTRY

categoria

Chemistry; Polymer Science

autores

Shatalov, AA; Evtuguin, DV; Neto, CP

nossos autores

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