Sodium phase diagram

Fig. 6. Phase diagram of the Na20—H2O—P20 (sodium orthophosphate) system at 25°C.

Fig. 1. Binary soap—water phase diagram for sodium palmitate (4). Courtesy of Academic Press, Ltd.

For sodium palmitate, 5-phase is the thermodynamically preferred, or equiUbrium state, at room temperature and up to - 60° C P-phase contains a higher level of hydration and forms at higher temperatures and CO-phase is an anhydrous crystal that forms at temperatures comparable to P-phase. Most soap in the soHd state exists in one or a combination of these three phases. The phase diagram refers to equiUbrium states. In practice, the drying routes and other mechanical manipulation utilized in the formation of soHd soap can result in the formation of nonequilibrium phase stmcture. This point is important when dealing with the manufacturing of soap bars and their performance. 

Sodium is miscible with many metals in liquid phase and forms alloys or compounds. Important examples ate hsted in Table 9 phase diagrams ate available... 

References 37 and 167 present phase diagrams of sodium with other metals. 

Sodium thiosulfate, either the anhydrous salt, Na2S202, or the crystalline pentahydrate, is commonly referred to as hypo or crystal hypo. When a concentrated sodium thiosulfate solution (50—60 wt %) is cooled to <48° C, the pentahydrate, containing 63.7% Na2S202, crystallines in monoclinic transparent prisms as shown in the equiUbrium phase diagram (Fig. 1). The monohydrate [55755-19-6] and the heptahydrate [36989-91-0] are also known. 

Vanadium-Sodium Compounds Most Corrosive. Physical property data for vanadates, phase diagrams, laboratory experiments, and numerous field investigations have shown that the sodium vanadates are the lowest melting compounds and are the most corrosive to metals and refractories. These compounds are thought to form by either the vapor phase reaction of NaCI and V2O5 or by the combination of fine droplets of these materials upon the cooler parts of combustion equipment. 

An example for a partially known ternary phase diagram is the sodium octane 1 -sulfonate/ 1-decanol/water system [61]. Figure 34 shows the isotropic areas L, and L2 for the water-rich surfactant phase with solubilized alcohol and for the solvent-rich surfactant phase with solubilized water, respectively. Furthermore, the lamellar neat phase D and the anisotropic hexagonal middle phase E are indicated (for systematics, cf. Ref. 62). For the quaternary sodium octane 1-sulfonate (A)/l-butanol (B)/n-tetradecane (0)/water (W) system, the tricritical point which characterizes the transition of three coexisting phases into one liquid phase is at 40.1°C A, 0.042 (mass parts) B, 0.958 (A + B = 56 wt %) O, 0.54 W, 0.46 [63]. For both the binary phase equilibrium dodecane... 

No phase diagram is available for the sodium-copper system. 

Sodium-zinc alloys for phase diagram determination are prepared by melting the elements in glass tubes under H2- Samples of NaZujj are prepared by heating zinc for several hours above the melting point of NaZn,3 (557°C) with xs Na in alundum extraction thimbles with N2 or Ar in a steel bomb scaled with copper gaskets. Excess Na was removed by extraction with liq NHj. Both KZn,3 and KCd,2 were prepared in this manner. ... 

Assume that the cations build up a perfect sodium chloride structure matrix. The formula must be expressed as (Mg, Al)10Ov To make sure that this formula is in agreement with the measured ratio of MgO and A1203 represented on the phase diagram use the following procedure ... 

Sodium chloride-water system, phase diagram of, 22 801—802 Sodium chlorite, 6 133 Sodium chloroacetate, 1 139—140 Sodium AT-chlorobenzenesulfonamide (chloramine B), 4 54 Sodium AT-chloroimidodisulfonate, 4 54... 

Thus for undiluted polymers the relaxation behaviour can be examined over a wider range of apparent frequencies. Similar functions can be constructed for other regions of the phase diagram and other rheological experiments. The method of reduced variables has not been widely tested for aqueous crosslinked polymers. Typically these are polyelectrolytes crosslinked by ionic species. Some of these give rise to very simple relaxation behaviour. For example 98% hydrolysed poly(vinyl acetate) can be crosslinked by sodium tetraborate. The crosslink that forms is shown in Figure 5.31. 

Olander, A., and Liander, H. (1950). The phase diagram of sodium chloride and steam above the critical point. Acta Chem. Scand. 4, 1437. 

Figure 3.7 Electrochemical phase diagram for sodium sulphide with elemental sulphur as metastable phase. Equilibrium lines (solid lines) correspond to dissolved species at 10" mol/L. Plotted points show the upper and lower limit potential of sulphur-included flotation of pyrite, pyrrhotite and arsenopyrite from literature...

Figure 3. Phase diagrams of the system water sodium dodecyl sulphate/alkanols benzene (a) ethanol (b) 2-propanol (c) 1-propanol(d) 1-butanol (e) 1-pentanol (f) 1-hexanol (g) 1-heptanol.

Figure 2. Phase diagram of a water-pentanol-sodium dodecyhulfate-p-xylene...

Figure 10. Ternary phase diagram at 298°K for systems of methanol in triolein with surfactant systems of bis(2-ethylhexyl) sodium sulfosuccinate, triethylammonium linoleate and tetradecyldimethylammonimum linoleate with 4/1 molar ratios of 2-octanol as co-surfactant.

Another way of ensuring that a glass surface is free of water or hydroxyl groups is to cover it with a film of sodium. This method was used when the melting point phase diagram for the system isobutene + titanium tetrachloride was determined (Longworth, Plesch and Rutherford, 1959 Plesch, 1972), but it cannot be used on silane-treated glass as the sodium will not spread on the waxy surface. 

Diphasic liquid systems used in CCC may have a wide variety of polarities. The most polar systems are the ATPS made by two aqueous-liquid phases, one containing a polymer, for example, polyethylene glycol (PEG), the other one being a salt solution, for example, sodium hydrogen phosphate. The less polar systems do not contain water there can be two-solvent systems, such as heptane/acetonitrile or dimethylsulfoxide/hexane systems or mixtures of three or more solvents. Intermediate polarity systems are countless since any proportion of three or more solvents can be mixed. Ternary phase diagrams are used when three solvents are mixed together. 

Reverse micelles are well known to be spherical water in oil droplets stabilized by a monolayer of surfactant. The phase diagram of the surfactant sodium bis(2-ethylhexyl) sulfosuccinate, called Na(AOT), with water and isooctane shows a very large domain of water in oil droplets and often forms reverse micelles (3,23). The water pool diameter is related to the water content, w = [H20]/[ AOT], of the droplet by (23) D(nm) = 0.3w. From the existing domain of water in oil droplets in the phase diagram, the droplet diameters vary from 0.5 nm to 18 nm. Reverse micelles are dynamic (24-27) and attractive interactions between droplets take place. 

Figure 11.1.9 shows the phase diagram of the ternary components of sodium bis(2-ethylhexyljsulfosuccinate (AOT), toluene, and water (24). The dotted line indicates... 

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