Carbon dioxide in aqueous solutions

Sodium acetate reacts with carbon dioxide in aqueous solution to produce acetic anhydride and sodium bicarbonate (49). Under suitable conditions, the sodium bicarbonate precipitates and can be removed by centrifugal separation. Presumably, the cold water solution can be extracted with an organic solvent, eg, chloroform or ethyl acetate, to furnish acetic anhydride. The half-life of aqueous acetic anhydride at 19°C is said to be no more than 1 h (2) and some other data suggests a 6 min half-life at 20°C (50). The free energy of acetic anhydride hydrolysis is given as —65.7 kJ/mol (—15.7 kcal/mol) (51) in water. In wet chloroform, an extractant for anhydride, the free energy of hydrolysis is strangely much lower, —50.0 kJ/mol (—12.0 kcal/mol) (51). Half-life of anhydride in moist chloroform maybe as much as 120 min. Ethyl acetate, chloroform, isooctane, and / -octane may have promise for extraction of acetic anhydride. Benzene extracts acetic anhydride from acetic acid—water solutions (52). 

Measurement of the absorption rate of carbon dioxide in aqueous solutions of sodium hydroxide has been used in some of the more recent work on mass-transfer rate in gas-liquid dispersions (D6, N3, R4, R5, V5, W2, W4, Y3). Although this absorption has a disadvantage because of the high solubility of C02 as compared to 02, it has several advantages over the sulfite-oxidation method. For example, it is relatively insensitive to impurities, and the physical properties of the liquid can be altered by the addition of other liquids without appreciably affecting the chemical kinetics. Yoshida and... 

The reaction products often compromise a mixture of various substances. Moreover, the reduction of carbon dioxide in aqueous solutions in the cathodic potential region is always accompanied by hydrogen evolution. Hence, an important criterion that describes the reaction selectivity is the faradaic yield ri for each individual Mh organic reaction product. 

Table 8. Data and Results of Fit on Solubility of Carbon Dioxide in Aqueous Solutions at 298.15°K...

Transfer hydrogenation and hydrogenolysis Hydrogenation of carbon dioxide in aqueous solution Hydrogenations of biological interest... 

Fosetyl readily degrades to phosphonic acid (H3PO3) and carbon dioxide in aqueous solution, soil and plant tissue and phosphonic acid is considered to be the active and systemic principle through the disruption of phospholipid metabolism. 

Carbon dioxide in aqueous solutions exist in three forms (i) physically dissolved CO2 (ii) bicarbonate ion HCOg and (iii) carbonate ion COj"-. In the physiological range of pH the latter form can be neglected. The bicarbonate ion HCOg is produced by the following hydration reaction ... 

Further details of the Leblanc process are omitted here for the reason that it is primarily of historical interest. The Solvay process is so superior in all respects that the Leblanc process is used little, if at all, at the present time and has never been used in the United States. However, it is interesting to point out that while the primary product of the Leblanc process is the normal carbonate, it may be converted to the acid carbonate by treatment with carbon dioxide in aqueous solutions ... 

When changing force field parameters of a compound, overall exactness of the model is determined by the parameterization criteria. As this work was parameterized to reproduce the solubility, which is related to the thermodynamic quantity of free energy, this raises the question of solvent structure, as the structure-energy relationship is evident even in the gas phase interactions. One way to test the solvent structure is to check the density of the aqueous solution as a rough estimate of the ability of the model to reproduce the correct intermolecular interaction between the solute and the solvent. For this purpose, additional MC simulations were carried out on the developed models to test their ability to reproduce the experimental density of solution, at the specified concentration. The density was calculated using the experimentally derived density equations for carbon dioxide in aqueous solution from Teng et al., which is calculated from the fyj, of the C02(aq) and the density of the pure solvent [36, 37]. 

R. A. Alberty. Standard transformed formation properties of carbon dioxide in aqueous solutions at specified pH. J. Phys. Chem., 99 11028-11034, 1995. 

The solubilities of carbon dioxide in aqueous solutions of mixed salts chosen from eight electrolytes (NaCl, KCl, Na2SO>, NH Cl, AfgSOj, (HHh)2SOh, CaCl2, KNOs) were measured at 25° C and 1 atm by the saturation method. Experimental results for the mixed-salt system were not described easily by the modified Setschenow Equation. However, they were correlated very well by an empirical two-parameter equation. The parameters in the equation for the binary and ternary salt solutions could be estimated easily from these equations for the components of the mixed salts. 

The solubility data of carbon dioxide in aqueous solutions of binary mixed salts obtained in this study are summarized in Table I those for ternary mixed salts are summarized in Tables II, III, and IV. Figures 1 and 2 show the solubility data for the potassium chloride-calcium chloride and sodium chloride-sodium sulfate-ammonium chloride mixed solutions, respectively, which are representative of all the data. The salting-out effect was shown in all the systems studied. 

O Leary M. H. (1984) Measurement of the isotope fractionation associated with diffusion of carbon-dioxide in aqueous-solution. J. Phys. Chem. 88(4), 823—825. 

Figure 3. The Henry constant of carbon dioxide in aqueous solutions of sodium sulfate at 25 °C (O) experimental data (a) the Henry constant calculated with eq 24 using for the mean activity coefficient of dissolved salt the Debye-Hiickel equation (b) the Henry constant calculated with eq 24 using for the mean activity coefficient of dissolved salt the extended Debye-Hiickel equation (c) the Henry constant calculated with eq 24 using for the mean activity coefficient of dissolved salt the Bromley equation (d) the Henry constant calculated with eq 15.

Garrison, W.M., Morrison, D.C., Hamilton, J.G., Benson, A. and Calvin, M., 1951. Reduction of carbon dioxide in aqueous solutions by ionizing radiation. Science, 114 416— 478. 

Getoff, N.G., Scholes, G. and Weiss, J., 1960. Reduction of carbon dioxide in aqueous solutions under the influence of radiation. Tetrahedron Lett., 18 17—23. 

GetofFN, Scholes G, Weiss J Reduction of Carbon Dioxide in Aqueous Solutions under the Influence of Radiation. Tetrahedron Letters I960, (18) 17-23. 

Jou, F-Y. Mather, A. and Otto, F. 1996, Solubility of Mixtures of Hydrogen Sulfide and Carbon Dioxide in Aqueous Solutions of Triethanolamine. Chem. Eng. Data., 41,1181-1183. 

Rumpf B, Xia J, Maurer G (1998) Solubility of carbon dioxide in aqueous solutions containing acetic acid or sodium hydroxide in the temperature range from 313 to 433 K and at total pressures up to 10 MPa. Ind Eng Chem Res 37 2012-2019... 

The common commercially available metals can be used for carbon dioxide installations (those not handling carbon dioxide in aqueous solutions). Any carbon dioxide system at the user s site must be designed to safely contain the pressures involved and must conform with all state and local regulations. See also CGA G-6.1, Standard for Low Pressure Carbon Dioxide Systems at Consumer Sites. [2] For low-pressure carbon dioxide systems (up to 400 psig or 2758 kPa), containers and related equipment should have design pressures rated at least 10 percent above the normal maximum operating pressure. 

Since carbon dioxide forms carbonic acid when dissolved in water, systems handling carbon dioxide in aqueous solutions must be fabricated from such acid-resistant materials as certain stainless steels, Hastelloy metals, or Monel metal. 

Falk M, Miller AG (1992) Infrared spectrum of carbon dioxide in aqueous solution. Vibr Spectrosc 4 105-108... 

Flaisher H, Tenne R, Hahnann M (1996) Photoelectrochemical reduction of carbon dioxide in aqueous solutions on p-GaP electrodes an a.c. impedance study with phase-sensitive detection. J Electroanal Chem 402(l-2) 97-105... 

Horton (Ref. 16) studied the absorption of carbon dioxide and ammonia in water on a single 18-in.-diameter plate and reported values of E%[y about 3 per cent for CO2, and 70 per cent for ammonia. Fair-brother (Ref. 9) studied the absorption of carbon dioxide in aqueous solutions of glycerine and obtained values of the Murphree plate efii-ciency of 0.65 to 4 per cent. 

Goldman, A. M and Leibush, A. G., 1959, Solubility of Carbon Dioxide in Aqueous Solutions of Monoethanolamine in the Temperature Range 75-140°C, Trudy Gasudarst, Nauch.-lssledov Praekt. Inst.-Azot. Prom., Vol. 10, pp. 54-82. 

The reaction of peroxynitrite with carbon dioxide in aqueous solution shows a significant barrier in the free energy profile of the reaction in solution (exp. 12 kcal/mol calc. 12.4 kcal/mol). The barrier vanishes completely for the reaction in vacuum. This difference again results since the solvation pattern implicates the breaking and forming of several hydrogen bonds [670]. 

The report on the solubility of carbon dioxide in aqueous solutions of arsenous oxide, arsenic pentoxide, and hydrogen chloride by Robb and Zimmer (1968) affords several points of interest in the present context. That work was done in connection with an attempt to correct to standard states in the combustion... 

D. Silkenbaumer, B. Rumpf, R.N. Lichtenthaler, Solubihty of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1-propanol and N-methyldiethanolamine and their mixtures in the temperature range from 313 to 353 K and pressures up to 2.7 MPa. Ind. Eng. Chem. Res. 37(8), 3133-3141 (1998)... 

---