Aqueous salt

Albumins. Soluble proteins both in water and in dilute aqueous salt solutions found in all living tissue. Typical albumins are ovalbumin from eggs and lactalbumin from milk. 

Solution Polymerization. Solution polymerization is widely used ia the acryhc fiber iadustry. The reactioa is carried out ia a homogeaeous medium by usiag a solveat for the polymer. Suitable solveats can be highly polar organic compounds or inorganic aqueous salt solutions. 

Hydrated amorphous silica dissolves more rapidly than does the anhydrous amorphous silica. The solubility in neutral dilute aqueous salt solutions is only slighdy less than in pure water. The presence of dissolved salts increases the rate of dissolution in neutral solution. Trace amounts of impurities, especially aluminum or iron (24,25), cause a decrease in solubility. Acid cleaning of impure silica to remove metal ions increases its solubility. The dissolution of amorphous silica is significantly accelerated by hydroxyl ion at high pH values and by hydrofluoric acid at low pH values (1). Dissolution follows first-order kinetic behavior and is dependent on the equilibria shown in equations 2 and 3. Below a pH value of 9, the solubility of amorphous silica is independent of pH. Above pH 9, the solubility of amorphous silica increases because of increased ionization of monosilicic acid. 

Therefore, manufacture of thioglycohc acid is associated with the production of aqueous salt waste, so problems of waste disposal have to be resolved ia each plant. 

Neutral aqueous salt solutions react slowly with tin when oxygen is present but oxidizing salt solutions, such as potassium peroxysulfate, ferric chloride and sulfate, and aluminum and stannic chlorides dissolve tin. Nonaqueous organic solvents, lubricating oils, and gasoline have Httle effect. 

The catalysts are prepared by impregnating the support with aqueous salts of molybdenum and the promoter. In acidic solutions, molybdate ions are present largely in the form of heptamers, [Mo2024] , and the resulting surface species are beHeved to be present in islands, perhaps containing only seven Mo ions (100). Before use, the catalyst is treated with H2 and some sulfur-containing compounds, and the surface oxides are converted into the sulfides that are the catalyticaHy active species. 

Aqueous salt solutions such as saturated 2inc chloride [7646-85-7] or calcium thiocyanate [2092-16-2] can dissolve limited amounts of cellulose (87). Two non-aqueous salt solutions are ammonium thiocyanate [1762-95-4]— uoamonia. and lithium chloride /744Z-4/A/—dimethyl acetamide [127-19-5]. Solutions up to about 15% can be made with these solvents. Trifluoroacetic acid [76-05-17—methylene chloride [75-09-2] and /V-methy1morpho1ine N-oxide [7529-22-8]—(92—94) are two other solvent systems that have been studied (95). 

One problem limiting the consideration of salt extractive distillation is the fact that the performance and solubility of a salt in a particiilar system is difficult to predict without experimental data. Some recent advances have been made in modeling the X T.E behavior of organic-aqueous-salt solutions using modified UNIFAC, NRTL, UNIQUAC, and other approaches [Kumar, Sep. Sci. Tech., 28(1), 799 (1993)]. 

The data of rhodamine 6G solubility in aqueous-salt solutions at different pH value are given. 

Sephadex. Other carbohydrate matrices such as Sephadex (based on dextran) have more uniform particle sizes. Their advantages over the celluloses include faster and more reproducible flow rates and they can be used directly without removal of fines . Sephadex, which can also be obtained in a variety of ion-exchange forms (see Table 15) consists of beads of a cross-linked dextran gel which swells in water and aqueous salt solutions. The smaller the bead size, the higher the resolution that is possible but the slower the flow rate. Typical applications of Sephadex gels are the fractionation of mixtures of polypeptides, proteins, nucleic acids, polysaccharides and for desalting solutions. 

Mulliii, J.W. and Raven, K.D., 1961b. Influence of mechanical agitation on the nucleation of some aqueous salt solutions. Nature, 195, 35-38. 

Bell has calculated Hq values with fair accuracy by assuming that the increase in acidity in strongly acid solutions is due to hydration of hydrogen ions and that the hydration number is 4. The addition of neutral salts to acid solutions produces a marked increase in acidity, and this too is probably a hydration effect in the main. Critchfield and Johnson have made use of this salt effect to titrate very weak bases in concentrated aqueous salt solutions. The addition of DMSO to aqueous solutions of strong bases increases the alkalinity of the solutions. 

It has been found that the growth hormone can be obtained in crystalline form from human pituitary glands by procedures comprising (1) extraction of the fresh glands with acetone, (2) extraction of the acetone residue with aqueous salt solutions, (3) precipitation from aqueous salt solutions by the addition of suitable miscible organic solvents of alkaline and acid pH, and finally crystallization from aqueous salt solutions by the addition of suitable miscible organic solvents. 

Baeumel, A. and Tramposch, O, Investigation of Intercrystalline Grain Boundary Corrosion of Austenitic Manganese-chromium Steels by Water and Aqueous Salt Solutions , Werkst. Korros., 17, 110 (1966) C.A., 64, 13847d... 

Willert, H., Investigations of the Corrosion Resistance of a 13%Cr Steel in Aqueous Salt Solutions , Neue Huelle, 11 72 (1966) C.A., 65, 14954b Tousek, J., Passivity of Nickel , Colleclion Czech. Chem. Commun., 31, 3083 (1966) C.A.,... 

Greiss, J. C., Crevice Corrosion of Titanium in Aqueous Salt Solutions Corrosion, 24, 96 (1968)... 

The ease with which an aqueous salt solution conducts electric current is determined by how much salt is dissolved in the water, as well as by the fact that ions are formed. A solution containing 0.1 moles per liter conducts much more readily than a solution containing 0.01 moles per liter. Thus the conductivity is determined by the concentration of ions, as well as by their presence. 

When an ionic solid like sodium chloride is melted, the molten salt conducts electric current. The conductivity is like that of an aqueous salt solution Na+ and Cl- ions are present. The extremely high melting temperature (808°C) shows that a large amount of energy is needed to tfear apart the regular NaCl crystalline arrangement to free the ions so they can move. 

In the case of aqueous salt solutions, the observed molecular lowering was invariably greater than the calculated. In this case we put instead of (4) ... 

A similar method was used in connexion with the lowering of vapour pressure in 130. It is evident that, since the factor i was introduced in the same connexion in both investigations, the values of i obtained by both methods, viz., by measurements of vapour pressure and of freezing-point, are necessarily the same, and their agreement is therefore independent of any theory which we may adopt to explain the anomalous behaviour of aqueous salt solutions. 

In 1930, DuPont launched the synthetic fiber industry with the discovery of nylon-6,6.2 In 1938, a pilot plant for nylon-6,6 production was put into operation, and in 1939, production was commenced at a large-scale plant in Seaford, Delaware. The classical method for the synthesis of nylon-6,6 involves a two-step process. In the first step, hexamethylene diamine (HMDA) is reacted with adipic acid (AA) to form a nylon salt. Polymerization of the aqueous salt solution is carried out at temperatures in the range of about 210-275°C at a steam pressure of about 1.7 MPa. When 275°C is reached, the pressure is reduced to atmospheric pressure and heating is continued to drive the reaction to completion. 

The permeability tests for alkali metal ions in the aqueous solution were also conducted. When an aqueous salt solution moves to cell 2 through the membrane from cell 1, the apparent diffusion coefficient of the salt D can be deduced from a relationship among the cell volumes Vj and V2, the solution concentration cx and c2, the thickness of membrane, and time t6 . In Table 12, permeabilities of potassium chloride and sodium chloride through the 67 membrane prepared by the casting polymerization technique from the monomer solution in THF or DMSO are compared with each other and with that the permeability through Visking dialyzer tubing. The... 

Tanford, Charles. The electrostatic free energy of globular protein ions in aqueous salt solution. Journal of Physical Chemistry 59 (1955) 788-793. 

The most widely used homogeneous catalysts are simple acids and bases which catalyse well-known reactions such as ester and amide hydrolysis, and esterification. Such catalysts are inexpensive enough that they can be neutralized, easily separated fi om organic materials, and disposed of. This, of course, is not a good example of green chemistry and contributes to the huge quantity of aqueous salt waste generated by industry. 

As discussed in Section 3-, whenever an ionic solid dissolves in water, the salt breaks apart to give a solution of cations and anions. Thus, in any aqueous salt solution the major species are water molecules and the cations and anions generated by the salt. For example, a solution of potassium chloride contains K and Cl ions and H2 O molecules as major species. Likewise, the major species in a solution of ammonium nitrate are NH4 , NO3, and H2 O. 

Figure 2. Molecular weight calibration curves for nonionic polyacrylamide for a single column (4 ft X Vs in. i.d.) containing 2000 A CPG-10 (200/400 mesh) packing with aqueous salt solutions as mobile phase.

Albumins, characterized by their solubility in water, and in diluted aqueous salt solutions... 

Globulins, soluble in diluted aqueous salt solutions, but insoluble or sHghtly soluble in distilled water... 

A model of blending aqueous salt buffers for chromatography has been developed.1 The model assumed full miscibility, low mixing enthalpy and low volume change. It reproduced experimental S-curves of buffer strength produced by a Pharmacia P3500 dual piston system equipped with a model 24 V dynamic mixer with 0.6 mL internal volume as well as those produced by a BioSepra ProSys 4-piston system equipped with two dynamic mixers of 1.2 mL internal volume. 

Kaltenbrunner, O. and Jungbauer, A., Simple model for blending aqueous salt buffers. Application to preparative chromatography, /. Chromatogr. A, 769, 37, 1997. 

With a three-component system, such as a polymer in an aqueous salt solution, preferential adsorption of one component to the polymer can affect the analysis of light-scattering data.199 Such interactions can affect the SRI. Therefore, measurements of the SRI must be made at constant chemical potential. Constant chemical potential is achieved experimentally by dialyzing the solvent and polymer solution to equilibrium through a membrane permeable to the solvent but impermeable to the polymer.199... 

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