DELIGNIFICATION OF EUCALYPT WOOD (EUCALYPTUS-GLOBULUS) IN ACETIC-ACID WATER MEDIA - EFFECT OF PRESSURIZED OXYGEN ADDITION

resumo

The delignification of E. globulus wood by acetic acid/water solutions (80:20, VN) has been studied at 140-150-degrees-C, without the presence of any catalyst (autocatalyzed solvolysis). A degree of delignification of 90% can be obtained with a pulp yield of 50%, but with cooking times relatively high; lignin condensation and reprecipitation is observed if cooking is extended. In the presence of oxygen (15 bar at 25-degrees-C) (oxydative solvolysis), a net increase in reaction kinetics is observed and the degree of delignification is higher. Pulp yields always exceed 50% but cellulose DPv are relatively small as a consequence of fiber degradation in the presence of oxygen. The chemistry of solvent pulping, with or without oxygen is discussed.

palavras-chave

BEHAVIOR; ETHERS; LIGNIN

categoria

Forestry; Materials Science

autores

NETO, CP; ROBERT, A

nossos autores

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