Carbon dioxide 157 dissolution

The presence of the complex carbohydrates provides the environment with a viscous hydrogel structure water removal gradually yields a mass of bacteria bound by undigested carbohydrates (celluloses) to form the stool. The presence of a hydrogel softens the mass and also provides water for dissolution. Carbon dioxide release is also a fermentation product, and if the redox potential is sufficiently low, bacteria can produce methane and hydrogen that can be detected in the breath particularly after the ingestion of pulses. In the upright position, the gas will rise to the transverse colon It is estimated that an adult produces approximately 2-3 L per day on 20 g fermentable fibre (most of which is eliminated in the breath). ... 

Neutralizing Amines. Neutralizing amines are used to neutralize the acid (H" ) generated by the dissolution of carbon dioxide or other acidic process contaminants in the condensate. These amines hydrolyze when added to water and generate the hydroxide ions required for neutralization ... 

Total carbon in beryUium is determined by combustion of the sample, along with an accelerator mixture of tin, iron, and copper, in a stream of oxygen (15,16). The evolved carbon dioxide is usuaUy measured by infrared absorption spectrometry. BeryUium carbide can be determined without interference from graphitic carbon by dissolution of the sample in a strong base. BeryUium carbide is converted to methane, which can be determined directly by gas chromatography. Alternatively, the evolved methane can be oxidized to carbon dioxide, which is determined gravimetricaUy (16). 

Dissolution Some waters continuously dissolve appreciable amounts of copper . Factors that favour this action are high free carbon dioxide, chloride and sulphate contents, low hardness, and increase of temperature. The trouble is therefore most prevalent in hot, soft, acid waters. The corrosion is general and the resulting thinning is so slight that the useful life of the pipe or component is virtually unaffected (unless impingement attack... 

The effect of pH on the corrosion of zinc has already been mentioned (p. 4.170). In the range of pH values from 5 -5 to 12, zinc is quite stable, and since most natural waters come within this range little difficulty is encountered in respect of pH. The pH does, however, affect the scale-forming properties of hard water (see Section 2.3 for a discussion of the Langelier index). If the pH is below the value at which the water is in equilibrium with calcium carbonate, the calcium carbonate will tend to dissolve rather than form a scale. The same effect is produced in the presence of considerable amounts of carbon dioxide, which also favours the dissolution of calcium carbonate. In addition, it is important to note that small amounts of metallic impurities (particularly copper) in the water can cause quite severe corrosion, and as little as 0-05 p.p.m. of copper in a domestic water system can be a source of considerable trouble with galvanised tanks and pipes. 

The pentafluorophenylcopper tetramer is usually analytically pure as isolated and melts at 200° with decomposition. If any significant decomposition occurs during the final drying, the product can be purified by dissolution in ether, filtration to remove copper metal, and precipitation by addition of hexane. It can also be recrystallized from benzene. When kept in a sealed container under nitrogen at room temperature, pentafluorophenyl copper tetramer appears to be stable for reasonable periods. It can be stored indefinitely at -78° under an atmosphere of carbon dioxide. 

Lj + G —> L2 Absorption of gases in water Dissolution of gases like hydrogen chloride, ammonia and carbon dioxide in water... 

The dissolution of porous minerals, the combustion of porous carbon, the reaction between porous carbon and carbon dioxide, and the formation of nickel carbonyl from pure nickel are some examples of fluid-solid reactions where the reactant solid is porous and where no solid reaction product is formed. A reaction of this type can be represented as... 

The presentation finally descends on the very last of the listed chemical precipitation processes, and this pertains to precipitation implemented by carbonate anions (CO-). The dissolution of carbon dioxide takes place with the formation of the weak diabasic acid, H2C03. The overall dissociation of this acid (dissociation constant, KD) is represented by ... 

Sodium bicarbonate tablets are administered in increments of 325 and 650 mg tablets. A 650 mg tablet of sodium bicarbonate contains 7.7 mEq (7.7 mmol) each of sodium and bicarbonate. Sodium retention associated with sodium bicarbonate can cause volume overload, which can exacerbate hypertension and chronic heart failure. Patient tolerability of sodium bicarbonate is low because of carbon dioxide production in the GI tract that occurs during dissolution. 

Carbon dioxide can change the pH of water because of its slightly dissolution in water to form carbonic acid, H2COs (a weak acid), according to Equation 9 ... 

Gholami Y., Azin R., et al. Prediction of carbon dioxide dissolution in bulk water under isothermal pressure decay at different boundary conditions. 2015 Journal of Molecular Liquids 202 23-33. 

Both of these facts are employed in the carbonation process of sodas and beer and some sparkling wines. Low-temperature conditions and CO2 pressures of 3 to 4 atm are used to enhance the dissolution of carbon dioxide gas in water. The graph in Fig. 3.1.1 presents the solubility of carbon dioxide in water at various temperatures and pressures. The parameter used to express CO2 solubility is... 

To a flame-dried, three-neck, 1-1 flask were added, in order, p-xylene (107 g, 1.0 mol), phosphorus trichloride (412 g, 3.0 mol), and anhydrous aluminum chloride (160 g, 1.2 mol). The reaction mixture was slowly heated to reflux with stirring. After 2.5 h at reflux, the reaction was allowed to cool to room temperature and the volatile components distilled at reduced pressure. The residual oil was slowly added to cold water (1 1) with stirring, and a white solid formed. The solid was removed by filtration, washed with water, and air dried. The solid was suspended in water (1 1) to which was added 50% sodium hydroxide solution (90 ml) to cause dissolution. The solution was saturated with carbon dioxide and filtered through Celite . The basic solution was washed with methylene chloride (200 ml) and acidified with concentrated hydrochloric acid (200 ml). The white solid that separated was isolated by extraction with methylene chloride (3 x 250 ml). The extracts were dried over magnesium sulfate, filtered, and evaporated under reduced pressure to give the pure 2,5-dimethylbenzenephosphinic acid (99 g, 60%) as an oil, which slowly crystallized to a solid of mp 77-79°C. 

Econamine FG [Flue gas] A process for removing carbon dioxide from flue-gases by dissolution in an aqueous solution of monoethanolamine and a proprietary corrosion inhibitor. Originally developed by the Dow Chemical Company under the designation Gas/Spec FT, the process was acquired in 1989 by the Fluor Corporation and is now licensed by that company. 

---