Calcium salt solubility

Figure 5 shows the calcium salt solubility in the mixed systans of NaGCDC-NaGUDC-EL as a function of pH. The solubility exhibited a convex curve with a maximum at pH 8.0. This suggests that the dissolution of calcium salt differs from the systan without EL as shown in Figure 4. 

Figure 7 shows the calcium salt solubility in the mixed... 

Figure 4 Calcium salt solubility in the mixed system of NaGCDC-NaGUDC as a function of pH.

Certain of these acids are used in the manufacture of black azo-colours. A mixture of acids is formed by sulphonation of naphthionic acid with fuming sulphuric acid, and these are separated by treating the calcium salts of the mixture with alcohol. The calcium salt soluble in alcohol of 96 % yields add No. I., the residue contains acids II. and III., of which II. is soluble in alcohol of 85 Acid I. yields azo-colours of no value, and No. III. is of greater importance than No. II. Germ. Pat. 41957, Sept. 4, 1886. 

The concentrations of oxalate, malonate, and other difunctional carboxylate ions are probably limited by the very low solubility of their respective calcium salts (Table 3) and their susceptibility to thermal degradation as discussed below. The monofunctional carboxylate ions listed in Table 2 have calcium salt solubilities that are orders of magnitude greater than those of the dicarboxylate ions (Table 3). Thus, maximum concentrations of acetate and other monofunctional carboxylate ligands are more likely controlled by their relative rates of production and thermal degradation... 

Detergents are made by, for example, treating petroleum hydrocarbons with sulphuric acid, yielding sulphonated products which are water soluble. These can also solubilise fats and oils since, like the stearate ion, they have an oil-miscible hydrocarbon chain and a water-soluble ionic end. The calcium salts of these substances, however, are soiu u-ic in water and, therefore, remove hardness without scum formation. 

These are similar to those of the alkali metals but are rather less soluble in water. However, calcium sulphide, for example, is not precipitated by addition of sulphide ions to a solution of a calcium salt, since in acid solution the equilibrium position... 

The chromates of the alkali metals and of magnesium and calcium are soluble in water the other chromates are insoluble. The chromate ion is yellow, but some insoluble chromates are red (for example silver chromate, Ag2Cr04). Chromates are often isomorph-ous with sulphates, which suggests that the chromate ion, CrO has a tetrahedral structure similar to that of the sulphate ion, SO4 Chromates may be prepared by oxidising chromium(III) salts the oxidation can be carried out by fusion with sodium peroxide, or by adding sodium peroxide to a solution of the chromium(IIl) salt. The use of sodium peroxide ensures an alkaline solution otherwise, under acid conditions, the chromate ion is converted into the orange-coloured dichromate ion ... 

Detergents are designed to be effective in hard water meaning water containing calcium salts that form insoluble calcium carboxylates with soaps These precipitates rob the soap of Its cleansing power and form an unpleasant scum The calcium salts of synthetic deter gents such as sodium lauryl sulfate however are soluble and retain their micelle forming ability even m hard water... 

Saccharin was discovered at Johns Hopkins Uni versity in 1879 in the course of research on coal tar derivatives and is the oldest artificial sweetener In spite of Its name which comes from the Latin word for sugar saccharin bears no structural relationship to any sugar Nor is saccharin itself very soluble in wa ter The proton bonded to nitrogen however is fairly acidic and saccharin is normally marketed as its water soluble sodium or calcium salt Its earliest applications were not in weight control but as a... 

Docusate Calcium. Dioctyl calcium sulfosuccinate [128-49-4] (calcium salt of l,4-bis(2-ethylhexyl)ester butanedioic acid) (11) is a white amorphous soHd having the characteristic odor of octyl alcohol. It is very slightly soluble in water, and very soluble in alcohol, polyethylene glycol 400, and com oil. It may be prepared directly from dioctyl sodium sulfo succinate dissolved in 2-propanol, by reaction with a methan olic solution of calcium chloride. 

Blood Calcium Ion Level. In normal adults, the blood Ca " level is estabhshed by an equiUbrium between blood Ca " and the more soluble intercrystalline calcium salts of the bone. Additionally, a subtle and intricate feedback mechanism responsive to the Ca " concentration of the blood that involves the less soluble crystalline hydroxyapatite comes into play. The thyroid and parathyroid glands, the fiver, kidney, and intestine also participate in Ca " control. The salient features of this mechanism are summarized in Figure 2 (29—31). 

Calcium Phosphates. The alkaline-earth phosphates are generally much less soluble than those of the alkaH metals. Calcium phosphates include the most abundant natural form of phosphoms, ie, apatites, Ca2Q(P0 3X2, where X = OH, F, Cl, etc. Apatite ores are the predominant basic raw material for the production of phosphoms and its derivatives. Calcium phosphates are the main component of bones and teeth. After sodium phosphates, the calcium salts are the next largest volume technical- and food-grade phosphates. Many commercial appHcations of the calcium phosphates depend on thek low solubiHties. 

The reaction of magnesium noncarbonate hardness with lime and with soda ash is a two step reaction since reaction 6 produces a reasonably soluble calcium salt that must react with in order to cause calcium precipitation ... 

Salts of Organic Acids. Calcium salts of organic acids may be prepared by reaction of the carbonate hydroxide and the organic acid (9). Calcium lactate [814-80-2] is an iatermediate ia the purification of lactic acid from fermentation of molasses. Calcium soaps, soaps of fatty acids, ate soluble ia hydrocarbons, and are useful as waterproofing agents and constituents of greases (9). 

Lime-Sulfuric. Recovery of citric acid by calcium salt precipitation is shown in Figure 3. Although the chemistry is straightforward, the engineering principles, separation techniques, and unit operations employed result in a complex commercial process. The fermentation broth, which has been separated from the insoluble biomass, is treated with a calcium hydroxide (lime) slurry to precipitate calcium citrate. After sufficient reaction time, the calcium citrate slurry is filtered and the filter cake washed free of soluble impurities. The clean calcium citrate cake is reslurried and acidified with sulfuric acid, converting the calcium citrate to soluble citric acid and insoluble calcium sulfate. Both the calcium citrate and calcium sulfate reactions are generally performed in agitated reaction vessels made of 316 stainless steel and filtered on commercially available filtration equipment. 

Such a solution contains approximately 200 g. (2.3 moles) of potassium hypochlorite. Sodium or potassium hypochlorite may be used, but the calcium salt is not satisfactory because the calcium salt of /3-naphthoic acid is sparingly soluble. 

The calcium salt is thereby converted into the soluble potassium salt and calcium carbonate is precipitated. The latter is removed by filtration, as before, and the filtrate concentrated on the water-bath to a small volume until a drop of the liquid, removed on the end of a glass rod, crystallises at once on cooling. 

Propeyiies.—Crystals m. p. 79—So very soluble in water. The air-dried calcium salt contains thiee molecules of water of crystallisation and is soluble in 80 parts of water 15°, and in parts at looA See Appendix p 258. 

The acid, without drying, is suspended in about 200 cc. of distilled water and with vigorous stirring, cautiously (Note 3) treated with 25 per cent sodium hydroxide solution until dissolved and the solution reacts neutral to litmus. The solution is then filtered through folded filter paper which should be free from soluble calcium salts, otherwise the filtrate will remain clouded by a suspension of the calcium salt. The clear, faintly yellow or colorless filtrate is then vigorously stirred and treated with 1.5 volumes of 95 per cent alcohol. Crystallization is induced by rubbing with a rod and then an additional volume of alcohol is added. The mixture should be allowed to cool to about 200 and stand for at least two hours to complete the precipitation of the salt, which is then filtered by suction and washed thoroughly with 85 per cent alcohol. The salt is then air-dried. The yield is 73-77 g. (38-40 per cent of the theoretical amount). 

The precipitation of anhydrite (anhydrous calcium sulfate, CaS04) may also occur. Under ambient temperatures, anhydrite is much more soluble than calcium carbonate, but because calcium sulfate, in common with other calcium salts such as calcium phosphate (also known as tricalcium phosphate [Ca3(P04)2]), has an inverse-temperature solubility, it deposits more rapidly on the hottest heat transfer surfaces. 

The solubility of LAS is dependent on various factors. For homologs with different molecular weights, it is normally the case that the higher the molecular mass, the lower the solubility. If the homologs have the same molecular weights, those with symmetrical isomer distribution will be easily dissolved branched homologs lead to a deterioration of solubility. The Na salts of the 2-and 3-phenylalkanes are less soluble then those of the internal phenyl isomers (for calcium salts the opposite is true) [187,188]. 

Calcium salts have a low solubility in water but this is only true for dodecyl and higher sulfates. Pure octyl and decyl calcium sulfates are soluble substances. 

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