Sodium carbonate/water diagram

Figure 16.3. Enthalpy-composition diagrams of some salt solutions. Several other diagrams are in the compilation of Landolt-Bomstein, IV 4b, 1972, pp. 188-224. (a) sodium sulfate/water (b) magnesium sulfate/water (after Chemical Engineers Handbook, 1963 edition, McGraw-Hill, New York) (c) sodium carbonate/water.

ZA2 Zafarani-Moattar, M.T. and Nilgoo, D., Phase diagrams for liquid-liquid and liquid-solid equilibrium of the ternary polyfethylene glycol) dimethyl ether 2000 + sodium carbonate + water system, J. Chem. Eng. Data, 54, 2918, 2009. 

FIGURE 7.45. Sodium carbonate-water phase diagram. 

Figures 9 and 10 show phase-behavior diagrams for David Lloydminster crude oil and the surfactant Neodol 25-3S in the presence of 1 wt% sodium carbonate. Phase-behavior measurements were carried out according to the method of Nelson et al. (52). The David Lloydminster oil field is near the Alberta-Saskatchewan border directly east of Edmonton. The oil has a density of 0.922 g/mL and a viscosity of 144 MPa s at 23 °C. The region of optimal phase behavior is shown at a surfactant concentration of 0.1 wt% in Figure 9. The region of optimal phase behavior is shaded. Above this region, type II +) behavior occurs, and type II(-) behavior occurs below the region of optimal phase behavior. Volume percent oil refers to the amount of oil present in the phase-behavior tube used. For a given oil-to-water ratio, a transition from type II(-) to type III to type II(+) occurs as salinity increases. As the amount of oil increases relative to the amount of aqueous phase, the same trend in phase behavior is seen.

If the third component is a water-insoluble alcohol (five carbons or more), amine, carboxylic acid, or amide, the phase topography is profoundly modified. The phase diagram shown in Figure 3.8b [7] shows in addition to LI and HI a very large lamellar phase, a narrow reverse hexagonal phase H2, and, even more important, a sector-like area of reverse micelles L2. This means that the solubility of n-decanol in a sodium octanoate-water mixture containing between 25 and 62% amphiphile is far more important (30 to 36%) than pure water (4%) and pure sodium octanoate (almost zero). This phase is essential to obtain water-in-oil (w/o) microemulsions. 

Fig. 2.3-3 Triangular solubihty diagram of the system sodium-carbonate sodium sulphate-water...

Figure 7.45 is the phase diagram for sodium carbonate and water. Three different hydrates are involved, and there are phase transitions at 32°C and 35.4°C. The solid forms of most interest are the decahydrate (washing soda) and the monohydrate. The diagram shows that the solubility of the monohydrate is nearly thermoneutral. The solubility as Na2CC>3 is about 33% at 36°C and 31% at 80°C. The inverse solubility prevents crystallization from a solution as it cools during transfer, and soda ash storage in the slurry form is usually as the monohydrate. The temperature in the tank should remain above 43-46°C to prevent transition to the hepta- or decahydrate. 

Binary Soap-Water System Mixtures of soap in water exhibit a rich variety of phase structures (4, 5). Phase diagrams chart the phase structures, or simply phases, as a function of temperature (on the y-axis) and concentration (on the x-axis). Figure 2.1 shows a typical soap-water binary phase diagram, in this case for sodium pahnitate-water. Sodium palmitate is a fully saturated, 16-carbon chain-length soap. At lower temperatures, soap crystals coexist with a dilute isotropic soap solution. Upon heating, the solubility of soap increases in water. As the temperature is increased the soap becomes soluble enough to form micelles this point is named the Krafft point. The temperature boundary at different soap concentrations above which micelles or hquid crystalline phases form is named the Krafft boundary (5). 

This process can be illustrated by connecting an apparatus, A, for generating ammonia, Fig. 65, and an apparatus, B, for making washed carbon dioxide with a tower, O, filled with a sat. soln. of sodium chloride and fitted with four perforated iron discs as shown in the diagram. The tower is provided with an exit tube dipping in a beaker of water. The soln. is first sat. with ammonia, and then with carbon dioxide. In about an hour, crystals of sodium bicarbonate will be deposited on the perforated shelves. 

To construct the potential pH diagrams of the different elements, all their possible redox processes with water, oxygen, and hydrogen have to be taken into account, and the electrochemical potentials have to be calculated. In addition, the dissolution/precipitation equilibria (e.g., hydrolysis) have to be taken into consideration, as well. The main dissolved ions in groundwater (calcium, magnesium, sodium, and potassium cations hydrocarbonate/carbonate, chloride,... 

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