Aqueous Carboxylic Acid-Based Solutions for CO2 Capture

G.V.S.M. Carrera, L.C. Branco, M. Nunes da Ponte
LAQV - REQUIMTE - FCT- NOVA University,
Portugal

Keywords: CO2 capture, water, ionic liquids, carboxylates

Summary:

Aqueous Carboxylic Acid-Based Solutions for CO2 Capture Gonçalo V. S. M. Carrera a, Luís C. Branco a, Manuel Nunes da Ponte a a LAQV/REQUIMTE Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, CQFB/REQUIMTE, 2829-516 Caparica, Portugal. Contact e-mail GVSMC: goncalo.carrera@fct.unl.pt In the current energetic, environmental, economic context are highly sought effective systems to capture carbon dioxide. The present work combines, the concept water activation by carboxylate-based ionic liquids (ILs) to capture CO2 in the form of bicarbonates, [1] with the use of organic superbases in the design of these ILs, [2] and test of multi-functionalization in the optimization of CO2 uptake. [3] Considering this framework, it was tested formic acid, dicarboxylic, tricarboxylic, tetracarboxylic acids and the polymeric alginic acid, in combination with an organic superbase and variable quantity of water. It was tested ambient pressure (to simulate flue gas) and higher pressures of CO2 (to simulate natural gas conditions). The reactional mixtures were weighted previous and after reaction with CO2. Furthermore the reactional mixtures were evaluated by 1H-NMR, 13C-NMR, HMBC (Heteronuclear Multiple Bond Correlation) and FTIR in order to check the form and quantity of captured CO2. The Task-Specific Ionic Liquids (TSILs), designed for water activation in carbon dioxide capture, contain one to multiple equivalents (carboxylate functionalities) and present an associated low molecular weight. Moreover, the simplicity of preparation of these TSILs (an acid-base reaction), the low cost and availability of the reactants constitute clear advantages of these systems. [1] K. Anderson, M. P. Atkins, J. Estager, Y. Kuah, S. Ng, A. A. Oliferenko, N. V. Plechkova, A. V. Puga, K. R. Seddon and David F. Wassell, Green Chem., 2015, 17, 4340. [2] P. G. Jessop, D. J. Heldebrant, X. Li, C. A. Eckert and C. L. Liotta, Nature, 2005, 436, 1102. [3] G.V.S.M. Carrera, N. Jordão, L.C. Branco, M. N. da Ponte, Faraday Discuss., 2015, 183, 429.