Potassium carbonate solutions vapor pressure

Figure 5.2.2. CO2 equilibrium vapor pressures over potassium carbonate solutions (Astarita et al., 1983.) Reprinted, with permission, from G. Astarita, D. W. Savage, A. Bisio, Gas Treating with Chemical Solvents, Figure 2.4.1, p. 70, John Wiley Son, 1983. Copyright 1983, John Wiley Sons.

The equilibrium vapor pressure of CO2 over a solution containing the equivalent of 20% potassium carbonate as a function of conversion to bicarbonate, based on the data of Tosh et al. (1959), is presented in Figure 5-9. These authors, who investigated vapor/liquid equilibria for 20, 30, and 40% equivalent potassium carbonate solutions, found that the CO2 equilibrium vapor pressure remains practically the same for the range of 20 to 30%. This in effect confirms the observation of Buck and Leitch (1958) for commercial operations. The experimental CO2 vapor pressure data were used by Tosh el al. (1959) as the basis for calcu-... 

Figure 5-19. Equilibrium vapor pressure of CO2 over 30% potassium carbonate solution, two-thirds converted to KHCO3 + lOtS. Tosh etal., 1960i...

White granular powder or cubic crystals refractive index 2.071 darkens on exposure to hght density 5.56 g/cm Moh s hardness 2.5 melts at 455°C vaporizes at 1,547°C vapor pressure 1 and 5 torr at 912 and 1,019°C insoluble in water, alcohol and dilute acids soluble in ammonia solution and concentrated sulfuric acid, alkali cyanide, ammonium carbonate also soluble in potassium bromide and sodium thiosulfate solutions. 

Grayish-white metal hody-centered cubic crystalline structure density 19.3 g/cm3 melts at 3,422°C vaporizes at 5,555°C vapor pressure 1 torr at 3,990°C electrical resistivity 5.5 microhm-cm at 20°C modulus of elasticity about 50 to 57 x lO psi (single crystal) Poisson s ratio 0.17 magnetic sus-ceptibilty +59 x 10-6 thermal neutron absorption cross section 19.2 + 1.0 barns (2,200m/sec) velocity of sound, about 13,000 ft/sec insoluble in water practically insoluble in most acids and alkabes dissolves slowly in hot concentrated nitric acid dissolves in saturated aqueous solution of sodium chlorate and basic solution of potassium ferricyanide also solubibzed by fusion with sodium hydroxide or sodium carbonate in the presence of potassium nitrate followed by treatment with water... 

A solution of 690 g. (5.0 moles) of potassium carbonate in 2 1. of distilled water is prepared in a 4-1. polyethylene beaker or pail, and 500 g. of crushed ice and 300 ml. of ether are added. The cold reaction mixture is cautiously added to the carbonate solution with stirring. The pH of the aqueous layer becomes about 9. The ether layer is separated, and the aqueous layer is extracted with three 200-ml. portions of ether. The ether solutions are combined and washed with three 100-ml. portions of water. The ether solution is dried over anhydrous sodium sulfate, and the ether is removed by distillation. The oily residue is fractionated through a 15-cm. Vigreux column under reduced pressure. There is a fore-run of about 0.5 ml., and then 59-75 g. (60-77%) of l-bromo-2-fluoroheptane is collected at 70-78° (15 mm.) 25d 1.4408-1.4420. According to vapor phase chromatography, it is about 90% pure (Note 5). 

Deliquescence is a property of substances very soluble in water. When such substances, potassium carbonate or calcium chloride for example, are exposed to the air, the water vapor forms with the substance a small quantity of a saturated solution. This saturated solution has a lower vapor pressure than that of the atmosphere, that is, the water is held by the substance, it does not tend to escape, hence more water vapor is added from the air, and finally the substance is entirely dissolved in this condensed vapor. Common salt or sodium chloride often appears to deliquesce, but the deliquescence is due to the very soluble magnesium and calcium chlorides which are usually mixed with commercial sodium chloride. Sodium nitrate is very soluble in water at the ordinary temperature, but potassium nitrate is only slightly soluble. Hence potassium nitrate, and not sodium nitrate, is used in the manufacture of gunpowder. 

The solubility of chlorine per 100 cc. of water at 20° is 1.85 g. that of bromine is 3.58 g. and that of iodine 0.28 g. Both chlorine and bromine form crystalline hydrates, C12-8H20 and BrjTOHjO. They are stable only at low temperatures (0-9°). The increased solubility of bromine in potassium bromide solution is ascribed to the formation of KBr if such solutions are saturated with bromine, the vapor pressure of the latter is the same as that of a water solution saturated with bromine. However, the halogen can be removed completely by extraction with carbon disulfide or by a stream of air the KBra must be stable only in the presence of free bromine. The solubility of iodine in water is increased by potassium iodide to 1.4 g. per 100 cc. and in ethanol a 20% solution can be formed. 

Iron tetracarbonyl dihydride melts at —70°, and it has a vapor pressure of 11 mm. at —10° (extrapolated). However, it is very unstable when pure and decomposes below —10°. In a current of carbon monoxide, the dilute vapors do not decompose even at room temperature. In alkaline solution, the potassium salt, K2Fe(CO)4, is stable but is very sensitive to oxidation by air. 

The potassium carbonate system operates mainly isothermal-COg absorption at high pressure and COg release at low pressure. In the absorptim step the pressure is typically about 3.0 MPa (reformer pressure minus pressure losses), and the temperature may be 100°C. The COg is absorbed chemically by the conversion of potassium carbonate to bicarbonate. When the solution pressure is reduced to about atmospheric pressure, part of the COg and water vapor escape. COg release is assisted by steam stripping. The steam is raised in the regenerator reboiler heated by the gas from the LTS shift converter thus, some or most of the heat required by the COg removal process is derived from the heat in the incoming gas. The regenerated solution is returned to the absorber. 

Poly(itaconic acid) has also been prepared in a 0.2M/liter aqueous solution using potassium persulfate at 50 C over a 5-hr period under reduced pressure. After the polymer is reprecipitated twice into methanol-ethyl acetate, a polymer is isolated with a molecular weight of 1.64 x 10, determined by vapor pressure osmometry of a methanolic solution of the methyl ester prepared from the polymer [49]. Unfortunately Tsuchida and coworkers did not report on the quantitative extent to which poly(methyl itaconate) had been formed from this polymer (presumably by reaction with diazomethane). Consequently, there is little in the literature to confirm or dispute the paper by Braun and Azis el Sayed [97], which offered evidence that during the free-radical polymerization of itaconic acid, carbon dioxide evolves to a considerable extent. During the process, it seems that hydroxyl and formyl radicals are generated and incorporated in the macromolecule. It is proposed by these authors that the homopolymer of itaconic acid contains virtually no itaconic acid repeat units but rather intramolecular lactone rings and acetal- or hemiacetal-like moieties. Since the polymer remains soluble in the reaction solvent (dioxane). 

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