Behavior of an Organic Solvent Drop During the Supercritical Extraction of Emulsions

FACUNDO MATTEA; ÁNGEL MARTÍN; CONSTANTIN SCHULZ; PHILIP JAEGER; RUDOLF EGGERS; MARÍA JOSÉ COCERO

AICHE JOURNAL

JOHN WILEY & SONS INC

Año: 2010 vol. 56 p. 1184 - 1195

0001-1541

The behavior of a drop of dichloromethane in water in contact with CO2 at high pressure has been investigated with the purpose of analyzing the phenomena that takes place during the supercritical fluid extraction of emulsions process. Experiments have been performed with and without a solute (b-carotene) and a surfactant (n-octenylsuc- cinic anhydride-modified starch) dissolved in the drop, and the evolution of the drop volume as well as of the interfacial tension between the drop and the aqueous phase has been measured. Additionally, a mathematical model has been developed that allows describing the mass transfer. Results show that the drop undergoes swelling and shrinking processes due to diffusion of CO2 into the drop and dichloromethane out of the drop. CO2 concentration in the drop can be as high as 0.9 (molar fraction). Emulsion drops behave as miniature gas antisolvent precipitators and many particles are formed inside the drop. The interfacial tension between the drop and the aqueous phase increases during the process, therefore destabilizing the emulsion.