The CO2-water system. I. Study of the slower hydration-dehydration step

Patel, Ramesh C.; Boe, R. J.; Atkinson, Gordon

doi:10.1007/bf00713250

Cited by 15 publications

(9 citation statements)

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“…The ion pairing reaction [5] is shown for the K+ and C032-ions, as this is the most likely equilibrium to be of consequence in the studies reported here. Equilibria involving divalent cations are of more importance in natural waters (3), and the HC03-ion would also be involved in such equilibria (10, 11).…”

Section: The Square Brackets Indicate Concentration In Mol L-' (M)mentioning

confidence: 53%

“…Some 13C nmr, however, has been used to study the enzyme catalysis of reactions [2] assumed speciation reactions [l] to [5]. The discussion is supported by further Raman data and speciation calculations.…”

Section: The Square Brackets Indicate Concentration In Mol L-' (M)mentioning

confidence: 98%

“…The existence of the species H2C03(aq) has been postulated due to kinetic considerations (5,6). No actual spectroscopic evidence of this species seems to exist, and quantum mechanical calculations suggest that it is not a stable species in the gas phase (7,8).…”

Section: Introductionmentioning

confidence: 99%

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¹³C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

Abbott¹,

Buchanan²,

Kruus³

et al. 1982

Can. J. Chem.

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13C-nmr spectra of carbon dioxide in water are reported for a wide range in pH. Chemical shifts were determined for the following species: CO2(g), CO2(aq), HCO3−(aq), CO32−(aq). A linear relationship was found between the shift of the 13C line and the fraction of carbonate ion calculated to be present, as well as between the ratio of the area under the 1067 cm−1 (carbonate) Raman peak to the sum of the area under the 1067 cm−1 and 1017 cm−1 (bicarbonate) peaks and the fraction carbonate.

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Section: The Square Brackets Indicate Concentration In Mol L-' (M)mentioning

confidence: 53%

Section: The Square Brackets Indicate Concentration In Mol L-' (M)mentioning

confidence: 98%

See 1 more Smart Citation

¹³C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

Abbott¹,

Buchanan²,

Kruus³

et al. 1982

Can. J. Chem.

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“…It has been suggested that in some cases the apparent discrepancies may simply reflect an inappropriate estimate of used in the calculation of ^h2co3 (Knoche 1980). The most recent paper on carbonic acid dehydration (van Eldik & Palmer 1982) proposes that the value of 19 s_1 for ^h2co3 determined by Patel et al (1973) should be taken as the most reliable. The rather low value of Gibbons & Edsall has been explained by the fact that phosphate (used as a buffer in their solutions) was considered to have a catalytic effect on the rate of dehydration, and the rate constant was therefore corrected.…”

Section: T Heorymentioning

confidence: 99%

The dissolution of calcite in aqueous solution at pH < 4: kinetics and mechanism

Compton

Unwin

1990

Phil. Trans. R. Soc. Lond. A

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The requirements of any experimental investigation of a reaction, such as dissolution or precipitation, at the solid-liquid interface are delineated, and it is shown that no previously adopted experimental method successfully meets all of these criteria. A new strategy for studying such reactions is therefore proposed, and described specifically for the dissolution kinetics of calcium carbonate in acidic aqueous solution. This technique involves locating a calcite crystal in part of one wall of a rectangular duct, through which reactant flows under laminar conditions, and positioning either an amperometric or potentiometric detector electrode immediately adjacent to and downstream of the crystal. The rate of the reaction at the crystal surface is then followed by measuring the concentration of the reactant or products reaching the electrode as a function of solution flow rate. In this way both transport (to the crystal and detection system) and the surface topography of the crystal are defined and controllable, and, most importantly, the concentrations interrogated by the detector electrode are those pertaining at the crystal surface and not the bulk values, which are those probed with other (previous) methods. A mechanistic model for the dissolution reaction at pH < 4, H + + CaCO 3 → C a 2 + + HCO 3 − , is developed, and it is recognized that half-, first- and second-order reactions in surface H + constitute possible candidate heterogeneous processes. The model also takes the following homogeneous (solution) reactions into account: HCO 3 − + H + ⇌ H 2 C O 3 ⟶ k H 2 C O 3 C O 2 + H 2 O , K H 2 C O 3 = a H + a HCO 3 − / a H 2 C O 3 The backward implicit finite difference method is used to provide theory for the proposed flow cell experiment. Specifically this relates the rate of an n th order process at the crystal surface to the transport-limited current at an amperometric detector electrode, as a function of solution flow rate and cell-crystal-electrode geometry. The computational method selected allows both the full parabolic velocity profile and any value of n to be considered. The validity of the numerical approach is checked by invoking the Lévêque approximation (linearizing the parabolic velocity profile) and solving the problem analytically for n = 0 and 1. The numerical method is extended so that both parallel heterogeneous and homogeneous reactions are covered, specifically so that theory describing the mechanistic model can be derived as related to the flow cell experiment. The design and construction of the necessary experimental apparatus is described, along with experiments devised to prove the validity of the experimental approach. The results of flow cell dissolution experiments carried out with 0.25–1.0 mM HCl solutions are presented, and it is shown for the first time that the reaction between H + and calcite is not transport-controlled. Assuming k H 2 C O 3 = 20 s − 1 and K H 2 C O 3 = 3.06 × 1 0 − 4 M , a best fit to the data is obtained for a first-order heterogeneous process with a rate constant of (0.043 ± 0.015) cm s -1 .

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“…The chemical reaction of CO 2 with water to form carbonic acid is clearly the central feature of these carbonate equilibria, and has been addressed by many experiments [5,16,[18][19][20][21][22][23][24][25][26] and calculations [17,[27][28][29][30][31][32][33][34][35][36] with conflicting results. Details of the neutral CO 2 solvation by bulk water prepare the reaction pathway, and are thus a determining factor in this chemistry.…”

Section: Introductionmentioning

confidence: 99%

The hydration structure of dissolved carbon dioxide from X-ray absorption spectroscopy

Lam

England

Smith

et al. 2015

Chemical Physics Letters

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a b s t r a c tThe dissolution of carbon dioxide in water and its subsequent hydrolysis reactions comprise one of the most central processes in all of science, yet it remains incompletely understood despite enormous effort. We report the detailed characterization of dissolved CO 2 gas through the combination of X-ray spectroscopy and first principles theory. The molecule acts as a hydrophobe in water with an average hydrogen bond number of 0.56. The carbon atom interacts weakly with a single water at a distance of >2.67Å and the carbonyl oxygens serve as weak hydrogen bond acceptors, thus locally enhancing the tetrahedral water hydrogen bonding structure.Published by Elsevier B.V.

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The CO2-water system. I. Study of the slower hydration-dehydration step

Cited by 15 publications

References 15 publications

¹³C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

¹³C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

The dissolution of calcite in aqueous solution at pH < 4: kinetics and mechanism

The hydration structure of dissolved carbon dioxide from X-ray absorption spectroscopy

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The CO2-water system. I. Study of the slower hydration-dehydration step

Cited by 15 publications

References 15 publications

13C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

13C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

The dissolution of calcite in aqueous solution at pH < 4: kinetics and mechanism

The hydration structure of dissolved carbon dioxide from X-ray absorption spectroscopy

Contact Info

Product

Resources

About

¹³C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

¹³C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems