Experimental measurements and correlation of the solubility of N,N-dialkylamides in supercritical carbon dioxide

N,N-Dialkylamides are the potential ligands for the extraction of actinides in nuclear-fuel cycle operations. Supercritical carbon dioxide (SCCO2) containing N,N-dialkylamides is a green solvent for the extraction of actinides with minimum liquid waste generation. In this connection, the solubilities of six N,N-dialkylamides in SCCO2 (313-333 K and 10-20 MPa) were measured to evaluate their utility as extractants for actinide separations. The solubilities are ranging from 0.005 x 10(-3) to 102 x 10(-3) mol mol(-1). The solubility of amides can be improved by increasing pressure and reducing temperature in the investigated region. The internal-consistency of solubility data was tested with Mendez-Teja equation. The solubility data was correlated with Chrastil, Mendez-Teja, solution theory with Wilson activity coefficient model and association theory with van Laar activity coefficient model. The correlation results demonstrated that, association theory with van Laar activity coefficient model predicts the solubilities with an average deviation of < 8% and is best among the models studied.