Crystallization of an organic compound from an ionic liquid using carbon dioxide as anti-solvent

In this paper the anti-solvency behavior of supercritical carbon dioxide (CO(2)) as a way to recover an organic compound from an ionic liquid by crystallization is explored. As an example, the conditions for crystallization of the organic compound methyl-(Z)-alpha-acetamido cinnamate (MAAC) from the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim(+)][BF(4)(-)]) using supercritical CO(2) as anti-solvent are studied experimentally by measuring the phase behavior of the ternary system [bmim(+)][BF(4)(-)] + CO(2) + MAAC. MAAC can be recovered from [bmim(+)][BF(4)(-)] by either using a shift to higher CO(2) concentrations at constant temperature (anti-solvent crystallization) or by using a shift to lower temperatures at constant CO(2) concentration (thermal shift).