Chiral ionic liquids based on L-cysteine derivatives for asymmetric aldol reaction

POCI-01-0145-FEDER–007265 PTDC/QUI-QOR/32406/2017 022161Structure, and consequently properties, of ionic liquids can be easily tailored by changing cation/anion combinations and/or attaching functional groups. By grafting enantiopure moieties to the framework of ionic liquid it is possible to prepare bioinspired chiral molecules that can serve as a reaction medium, additive or even asymmetric catalyst. In this context, new chiral ionic liquids (CILs), based on biomolecules, such as aminoacids (L-cysteine derivatives), have been synthesised and tested in asymmetric aldol condensation of aldehydes and ketones. The best results were obtained for CILs composed of S-methyl-L-cysteine cation and bis(trifluoromethane)sulfonimide anion, in the reaction of 2-or 4-nitrobenzaldehyde with acetone or cyclohexanone, giving the aldol product in moderate yields 70–76% and high ee values (up to 96%).publishersversionpublishe

Ionic Liquids for CO2 Capture and Reduction

As pointed out in the description of this thematic issue of C, with the current atmospheric levels of carbon dioxide being above 400 ppm, there is a growing interest in recycling this greenhouse gas in the form of valuable compounds [...

Solubility of carbon dioxide in ammonium based CO2-induced ionic liquids

The solubility of carbon dioxide in ionic liquids was measured in a new apparatus. The ionic liquids chosen have ammonium-based cations and show melting temperature decreases under CO2 pressure that range from low (25 K) to extremely high (120 K). The main purpose of this study was to check whether the solubility of the gas in each liquid could explain the previously reported wide differences in melting point depression (MPD). The results show there is no correlation between solubility and MPD

Solubility and phase behaviour of binary systems containing salts based on transitional metals

Tri(1-ethyl-3-methylimidazolium) gadolinium hexachloride ([emim]3[GdCl6]), tri(1-butyl-3-methylimidazolium) hexagadolinium chloride ([bmim]3[GdCl6]), di(tetramethylammonium) manganese tetrachloride ([TMA]2[MnCl4]) and cholinium tetrachloroferrate ([Chol][FeCl4]) were synthetized and their solubility in water, ethanol, 1-propanol and 1-butanol were determined as a funcion of temperature. Activity coefficients were calculated and their comparison with ideal solutions were discussed. The experimental data were correlated successfully by means of the semi-empirical Grant equation. In addition, melting point depression effect of high pressure carbon dioxide was studied