Resumo

BLANCO, Ernesto  e  ALFARO, Johnny. CHEMICAL MODIFICATION OF Calophyllum brasiliense Cambess. AND Enterolobium cyclocarpum (Jacq.) Griseb. WOOD. Colomb. for. [online]. 2014, vol.17, n.1, pp.125-132. ISSN 0120-0739.

Wood samples of two tropical hardwood species, Cedar Mary (Calophyllum brasiliense Cambess.) and Guanacaste (Enterolobium cyclocarpum (Jacq.) Griseb.), growing in Costa Rica were chemically modified by acetylation. Acetic anhydride was used as reagent and donor of the acetyl group, potassium carbonate as a catalyst and N,N-dimethylformamide (DMF) as a solvent. The reaction was carried out at 90° C and three reaction times were studied in order to determine the percentage weight gain (PWG) for every treatment. For the seven hour reaction, PWG was 12.88 % and 12.44 % for Guanacaste and Cedar Mary samples respectively. IR spectra using ATR technology were obtained in order to corroborate the reaction. Results showed characteristic signals of functional groups C = O (1737 cm^-1), C-O (1220 cm^-1) and C-H bending vibration for the acetyl group (1368 cm^-1), which indicates that hydroxyl groups had been replaced by acetyl groups. Longer reaction times increase this replacement in both species.

Palavras-chave : acetylation; acetic anhydride; Tropical hardwood; chemical mod.

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