13C NMR as a method species determination in CO2 absorbent systems

Ciftja, Arlinda F.; Hartono, Ardi; Svendsen, Hallvard F.

doi:10.1016/j.ijggc.2013.04.006

Cited by 70 publications

(56 citation statements)

References 28 publications

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“…This indicates that the sample preparation methods used has not changed the speciation significantly and that the results are representative of the original samples. However, for the very low loadings of the upper phase the uncertainty of particularly the titration method becomes very large and the measurements are also close to the detection limits of the NMR method (Ciftja et al, 2013a). This is the reason for the discrepancies seen for this phase.…”

Section: Nmr Experiments Of Blended Deea-mapa-co 2 -H 2 Omentioning

confidence: 86%

“…. The preloaded samples were kept at room temperature for about 24h and then analyzed for CO 2 and amine by titration and compared with the NMR analyses (Ciftja et al, 2013a).…”

Section: Sample Preparationmentioning

confidence: 99%

“…Amine-protonated amine, amine carbamate-protonated amine carbamate and bicarbonate-carbonate which involve proton transfers, have very rapid reaction rates with very small relaxation times. Therefore the 13 C NMR will average the peaks for these species (Ciftja et al, 2013a;Jakobsen et al, 2005).…”

Section: Reaction Mechanisms Of Aminesmentioning

confidence: 99%

“…The quantitative NMR experiments and the parameters used for the system are explained in the literature (Ciftja et al, 2013a). All the data were processed and calculated by the NMR software (MestReNova).…”

Section: Nmr Experiments On the Loaded Deea-co 2 -H 2 O Systemmentioning

confidence: 99%

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Experimental study on phase change solvents in CO2 capture by NMR spectroscopy

Ciftja

Hartono

Svendsen

2013

Chemical Engineering Science

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Abstract2-(Diethylamino)ethanol (DEEA) and 3-(Methylamino) propylamine (MAPA) in combination may represent a promising absorbent system for CO 2 capture due to high CO 2 loading capacity, high equilibrium temperature sensitivity, low energy requirement for regeneration and relatively high reaction rate.Three different systems: DEEA-CO 2 -H 2 O; MAPA-CO 2 -H 2 O and DEEA-MAPA-CO 2 -H 2 O were studied quantitatively by NMR spectroscopy and the data are reported in the present work. The main products quantified for these systems are: carbonate-bicarbonate for the DEEA-CO 2 -H 2 O system; primary, secondary carbamate, dicarbamate for the MAPA-CO 2 -H 2 O system, and primary/ secondary carbamate, dicarbamate, carbonate/bicarbonate in blended DEEA-MAPA-CO 2 -H 2 O. The speciation data of the three systems were measured and reported in the present work. The blended system of 5M DEEA-2M MAPA can form two liquid phases after being loaded with CO 2 and both phases were analyzed quantitatively by NMR spectroscopy. The experimental data shows that the lower phase is rich in CO 2 and MAPA while the upper phase was lean in CO 2 and rich in DEEA. The ratio DEEA-MAPA in the lower phase increases with increasing partial pressure whereas for the upper phase the opposite is true.

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Section: Nmr Experiments Of Blended Deea-mapa-co 2 -H 2 Omentioning

confidence: 86%

“…. The preloaded samples were kept at room temperature for about 24h and then analyzed for CO 2 and amine by titration and compared with the NMR analyses (Ciftja et al, 2013a).…”

Section: Sample Preparationmentioning

confidence: 99%

Section: Reaction Mechanisms Of Aminesmentioning

confidence: 99%

Section: Nmr Experiments On the Loaded Deea-co 2 -H 2 O Systemmentioning

confidence: 99%

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Experimental study on phase change solvents in CO2 capture by NMR spectroscopy

Ciftja

Hartono

Svendsen

2013

Chemical Engineering Science

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“…1 H and 13 C NMR is a better analytical option compared to titration and optical techniques because no calibration is needed and structure of molecules obtained enables byproduct analysis. Plenty of studies on speciation study in liquid phase and determination of equilibrium constants using NMR spectroscopy were reported (Böttinger et al, 2008;Ciftja et al, 2013;Ermatchkov et al, 2003;Jakobsen et al, 2005). However long acquisition time for quantitative 13 C NMR experiments is not desirable for kinetic experiments, therefore some researchers opted for vibrational spectroscopy for liquid phase analysis.…”

Section: Introductionmentioning

confidence: 99%

Chemical speciation of CO2 absorption in aqueous monoethanolamine investigated by in situ Raman spectroscopy

Wong

Bustam

Shariff

2015

International Journal of Greenhouse Gas Control

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NMR Study of CO₂ Capture by Butylamine and Oligopeptide KDDE in Aqueous Solution: Capture Efficiency and Gibbs Free Energy of the Capture Reaction as a Function of pH**

et al. 2023

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We have been interested in the development of rubisco-based biomimetic systems for reversible CO 2 capture from air. Our design of the chemical CO 2 capture and release (CCR) system is informed by the understanding of the binding of the activator CO 2 ( A CO 2 ) in rubisco (ribulose-1,5-bisphosphate carboxylase/ oxygenase). The active site consists of the tetrapeptide sequence Lys-Asp-Asp-Glu (or KDDE) and the Lys sidechain amine is responsible for the CO 2 capture reaction. We are studying the structural chemistry and the thermodynamics of CO 2 capture based on the tetrapeptide CH 3 COÀ KDDEÀ NH 2 ("KDDE") in aqueous solution to develop rubisco mimetic CCR systems. Here, we report the results of 1 H NMR and 13 C NMR analyses of CO 2 capture by butylamine and by KDDE. The carbamylation of butylamine was studied to develop the NMR method and with the protocol established, we were able to quantify the oligopeptide carbamylation at much lower concentration. We performed a pH profile in the multi equilibrium system and measured amine species and carbamic acid/ carbamate species by the integration of 1 H NMR signals as a function of pH in the range 8 � pH � 11. The determination of ΔG 1 (R) for the reaction RÀ NH 2 + CO 2 !RÀ NHÀ COOH requires the solution of a multi-equilibrium equation system, which accounts for the dissociation constants K 2 and K 3 controlling carbonate and bicarbonate concentrations, the acid dissociation constant K 4 of the conjugated acid of the amine, and the acid dissociation constant K 5 of the alkylcarbamic acid. We show how the multi-equilibrium equation system can be solved with the measurements of the daughter/parent ratio X, the knowledge of the pH values, and the initial concentrations [HCO 3 À ] 0 and [R-NH 2 ] 0 . For the reaction energies of the carbamylations of butylamine and KDDE, our best values are ΔG 1 (Bu) = À 1.57 kcal/mol and ΔG 1 (KDDE) = À 1.17 kcal/mol. Both CO 2 capture reactions are modestly exergonic and thereby ensure reversibility in an energy-efficient manner. These results validate the hypothesis that KDDE-type oligopeptides may serve as reversible CCR systems in aqueous solution and guide designs for their improvement.

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13C NMR as a method species determination in CO2 absorbent systems

Cited by 70 publications

References 28 publications

Experimental study on phase change solvents in CO2 capture by NMR spectroscopy

Experimental study on phase change solvents in CO2 capture by NMR spectroscopy

Chemical speciation of CO2 absorption in aqueous monoethanolamine investigated by in situ Raman spectroscopy

NMR Study of CO₂ Capture by Butylamine and Oligopeptide KDDE in Aqueous Solution: Capture Efficiency and Gibbs Free Energy of the Capture Reaction as a Function of pH**

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13C NMR as a method species determination in CO2 absorbent systems

Cited by 70 publications

References 28 publications

Experimental study on phase change solvents in CO2 capture by NMR spectroscopy

Experimental study on phase change solvents in CO2 capture by NMR spectroscopy

Chemical speciation of CO2 absorption in aqueous monoethanolamine investigated by in situ Raman spectroscopy

NMR Study of CO2 Capture by Butylamine and Oligopeptide KDDE in Aqueous Solution: Capture Efficiency and Gibbs Free Energy of the Capture Reaction as a Function of pH**

Contact Info

Product

Resources

About

NMR Study of CO₂ Capture by Butylamine and Oligopeptide KDDE in Aqueous Solution: Capture Efficiency and Gibbs Free Energy of the Capture Reaction as a Function of pH**