Brazilian Journal of Chemical Engineering
versão On-line ISSN 0104-6632
VIANA, L.M.; FREITAS, M.R.; RODRIGUES, S.V. e BAUMANN, W.. Extraction of lapachol from Tabebuia avellanedae wood with supercritical CO2: an alternative to Soxhlet extraction?. Braz. J. Chem. Eng. [online]. 2003, vol.20, n.3, pp. 317-325. ISSN 0104-6632. http://dx.doi.org/10.1590/S0104-66322003000300011.
The solubility of lapachol in supercritical CO2 was determined at 40°C and pressures between 90 and 210 bar. Supercritical fluid extraction of lapachol and some related compounds by CO2 from Tabebuia avellanedae wood is compared to Soxhlet extraction with different solvents. A standard macroscale (100-200 g wood) and a microscale (»10 mg wood) experimental setup are described and their results are compared. The latter involved direct spectrophotometric quantification in a high-pressure autoclave with an integrated optical path and a magnetic stirrer, fitted directly into a commercial spectrophotometer. The relative amount of lapachol extracted by supercritical CO2 at 40°C and 200 bar was about 1.7%, which is similar to the results of Soxhlet extractions. Lower contents of a- and b-lapachone as well as dehydro-a-lapachone are also reported.
Palavras-chave : solubility; supercritical; extractability; CO2; lapachol; lapachone; dehydro-a-lapachone.