Solubilities of Behenic Acid and Ethylbehenate in Supercritical Carbon Dioxide

Abstract

Solubilities of behenic acid (BA) and ethylbehenate (EB) in supercritical carbon dioxide (SCCO₂) are measured by a flow-type apparatus at 313 K from 12.3 to 22.1 MPa. The solubilities measured and their pressure dependence are analyzed by regular solution theory combined with the Flory-Huggins theory. The solubility of BA is very different from that by Chrastil, especially in the low pressure range. The solubility of EB is about 1, 000 times higher than that of BA. The higher solubility of fatty acid ethyl ester as compared with fatty acid seems effective to avoid solubility limitation of substrates in enzymatic reactions in SCCO₂.