IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
NMR investigation of chemical reactions of CO2, COS and CS2 in 1-butyl-3-methylimidazolium acetate ionic liquid
Autor/es:
F. VACA CHAVEZ; M. BESNARD; M: CABAÇO ; N. PINEAUD; PEDRO J. SEBASTIÃO; J. COUTINHO; J. MASCETTI; Y. DANTEN
Reunión:
Congreso; 9TH LIQUID MATTER CONFERENCE; 2014
Resumen:
In this work we present the solvation of carbon dioxide, carbon disulfide and carbonyl sulfide in 1-butyl-3-methylimidazolium acetate ([C4mim][Ac]) ionic liquid [1,2]. The study has been carried out by 1H, 13C, and 15N NMR spectroscopy. It is shown that a carboxylation reaction occurs between CO2 and Bmim Ac, leading to the formation of a non-negligible amount of 1-butyl-3-methylimidazolium-2-carboxylate. It is also found that acetic acid molecules are produced during this reaction and tend to form with elapsed time stable cyclic dimers existing in pure acid. Further experiments have been dedicated to characterize the influence of water traces on the carboxylation reaction. It is found that water does not hamper the formation of the carboxylate species but lead to the formation of byproduct involving CO2. The evolution with temperature of the resonance lines associated with the products of the reactions confirms that they have a different origin. The main byproduct has been assigned to bicarbonate. All these results confirm the existence of a reactive regime in the CO2? [C4mim][Ac] system but different from that reported in the literature on the formation of a reversible molecular complex possibly accompanied by a minor chemical reaction. In the case of the mixtures of [C4mim][Ac] with CS2 and OCS, the formation of1-butyl- 3-methylimidazolium-2-thiocarboxylate [C4mim] COS, CH3COS- and gaseous CO2 and OCS was observed. Our results also demonstrate that the anion plays an unexpected role not observed in the CO2?[C4mim][Ac] reaction. [1] M. Besnard, M. I. Cabaço, F. Vaca Chávez, N. Pinaud, P. J. Sebastião, J. A. P. Coutinho and Y. Danten, Chem Comm., 48, 1245 (2012). [2] M. I. Cabaço, M. Besnard, F. Vaca Chávez, N. Pinaud, P. J. Sebastião, J. A. P. Coutinho, J. Mascetti and Y. Danten, Chem Comm., 49, 11083 (2013).