Potassium salts, soluble

Solubility is also a function of the pK. The pX a values are phenol 9.98, 2,4,6-trichlorophenol 6.15, tetrachlorophenol 5.16 and pentachlorophenol 4.75 As a rule, the solubility of the anionic form is much higher than that of the molecular form. For example, the solubility of the herbicide loxynil (pX a = 3.96) in water is 50 mgp and that of its potassium salt solubility in water is 107 gl . The pX a value of pentachlorophenol is 4.75, and its solubility in water is 14 mg 1 whereas the solubility of the commercially produced sodium pentachlorophenoxide is 330 gl . This shows that pentachlorophenol is very soluble in nonacidic wastewater, and its leakage from factories can be very dangerous for the environment. 

CH OfiSj, H2C(S03H)2- a colourless, crystalline solid which readily absorbs water vapour decomposes on distillation. The potassium salt is prepared by heating methylene chloride with an aqueous solution of potassium sulphite under pressure at 150-I60" C. The free acid is obtained by decomposing the sparingly soluble barium salt with sulphuric acid. The aryl esters are very stable, but the alkyl esters decompose on heating to give ethers. Resembles malonic acid in some of its reactions. 

KCl —NaCl —MgS04) and in many brines. Separated by fractional crystallization, soluble water and lower alcohols. Used in fertilizer production and to produce other potassium salts. 

Sodium sulphate crystallises out in hydrated form (common ion effect) and is filtered off on concentration, sodium dichromate is obtained. For analytical purposes, the potassium salt. K2Cr20-. is preferred potassium chloride is added and the less soluble potassium dichromate obtained. 

Sodium dichromate is used instead of the potassium salt because it is far more soluble in water, and is not precipitated from its aqueous solution by addition of the ethanol. It is also cheaper than the potassium salt, but has the disadvantage of being deliquescent. 

Pure ethyl hydrogen sulphate is difficult to prepare, as it is an oily liquid, very soluble in water, and easily hydrolysed. It is therefore usually isolated as the potassium salt, since potassium ethyl sulphate crystallises well from water, and is not readily hydrolysed in neutral or weakly alkaline solution. 

It is frequently advisable in the routine examination of an ester, and before any derivatives are considered, to determine the saponification equivalent of the ester. In order to ensure that complete hydrolysis takes place in a comparatively short time, the quantitative saponi fication is conducted with a standardised alcoholic solution of caustic alkali—preferably potassium hydroxide since the potassium salts of organic acids are usuaUy more soluble than the sodium salts. A knowledge of the b.p. and the saponification equivalent of the unknown ester would provide the basis for a fairly accurate approximation of the size of the ester molecule. It must, however, be borne in mind that certain structures may effect the values of the equivalent thus aliphatic halo genated esters may consume alkali because of hydrolysis of part of the halogen during the determination, nitro esters may be reduced by the alkaline hydrolysis medium, etc. 

Vigorous oxidation of a monosaccharide (e.g., with dUute nitric acid) produces carboxyl groups at both ends of the chain. Thus galactose gives the sparingly soluble mucic acid glucose affords the soluble saccharic acid, which is best isolated as the sparingly soluble acid potassium salt. 

Saccharic acid. Use the filtrate A) from the above oxidation of lactose or, alternatively, employ the product obtained by evaporating 10 g. of glucose with 100 ml. of nitric acid, sp. gr. 1 15, until a syrupy residue remains and then dissolving in 30 ml. of water. Exactly neutralise at the boiling point with a concentrated solution of potassium carbonate, acidify with acetic acid, and concentrate again to a thick syrup. Upon the addition of 50 per cent, acetic acid, acid potassium saccharate sepa rates out. Filter at the pump and recrystaUise from a small quantity of hot water to remove the attendant oxahc acid. It is necessary to isolate the saccharic acid as the acid potassium salt since the acid is very soluble in water. The purity may be confirmed by conversion into the silver salt (Section 111,103) and determination of the silver content by ignition. 

Solvent Effects on the Rate of Substitution by the S 2 Mechanism Polar solvents are required m typical bimolecular substitutions because ionic substances such as the sodium and potassium salts cited earlier m Table 8 1 are not sufficiently soluble m nonpolar solvents to give a high enough concentration of the nucleophile to allow the reaction to occur at a rapid rate Other than the requirement that the solvent be polar enough to dis solve ionic compounds however the effect of solvent polarity on the rate of 8 2 reactions IS small What is most important is whether or not the polar solvent is protic or aprotic Water (HOH) alcohols (ROH) and carboxylic acids (RCO2H) are classified as polar protic solvents they all have OH groups that allow them to form hydrogen bonds... 

Metal carboxylates are ionic and when the molecular weight isn t too high the sodium and potassium salts of carboxylic acids are soluble m water Carboxylic acids therefore may be extracted from ether solutions into aqueous sodium or potassium hydroxide... 

Solid Compounds. The tripositive actinide ions resemble tripositive lanthanide ions in their precipitation reactions (13,14,17,20,22). Tetrapositive actinide ions are similar in this respect to Ce . Thus the duorides and oxalates are insoluble in acid solution, and the nitrates, sulfates, perchlorates, and sulfides are all soluble. The tetrapositive actinide ions form insoluble iodates and various substituted arsenates even in rather strongly acid solution. The MO2 actinide ions can be precipitated as the potassium salt from strong carbonate solutions. In solutions containing a high concentration of sodium and acetate ions, the actinide ions form the insoluble crystalline salt NaM02(02CCH2)3. The hydroxides of all four ionic types are insoluble ... 

Trisodium hexakiscyanoferrate [14217-21-17, Na2[Fe(CN) J, forms red hygroscopic crystals that are soluble in water. A monohydrate [13755-37-8] and a dihydrate [36249-31-7] are also known. The sodium salt is used for many of the same purposes as the potassium salt. 

The potassium salts are the most soluble and other salts usually are precipitated by addition of the appropriate metal chloride to a solution of the corresponding potassium salt. The metaniobates, MNbO, and orthoniobates, MNbO, generally are prepared by fusion of the anhydrous mixed oxides. The metaniobates crystallize with the perovskite stmeture and are ferroelectric (131) (see Ferroelectrics). The orthoniobates are narrow band-gap semiconductors (qv) (132). 

In addition to cost, several factors influence the choice of salt for a particular appHcation. The ammonium salt is the most soluble in water, but for some apphcations the presence of the ammonium ion maybe undesirable. The sodium salt is almost as soluble as the ammonium salt at ambient temperatures and above. The potassium salt is much less soluble. 

Table 1. World Reserves and Production of Soluble Potassium Salts, t x 10 K O...

To avoid generation of waste brines and the associated serious problem of brine disposal, the potash industry in the former FRG began converting some operations to electrostatic separation, a dry process for separating potassium salts from other soluble salts (24,25). 

Soluble Sta.nna.tes, Many metal staimates of formula M Sn(OH) are known. The two main commercial products are the soluble sodium and potassium salts, which are usually obtained by recovery from the alkaline detinning process. They are also produced by the fusion of stannic oxide with sodium hydroxide or potassium carbonate, respectively, followed by leaching and by direct electrolysis of tin metal in the respective caustic solutions in cells using cation-exchange membranes (27). Another route is the recovery from plating sludges. 

Because of its bitter taste and water iasolubiUty, guaiacol has been chemically modified to improve its properties. Sulfonation provides a mixture of guaiacol-4- and 5-sulfonic acids which, as the potassium salts, is water-soluble, comparatively tasteless, but less active than guaiacol. Treatment of the sodium salt of guaiacol with phosgene provides guaiacol carbonate [553-17-1] (3) which also lacks the bitter taste of guaiacol, but is less water-soluble. 

A mild and effective method for obtaining N- acyl- and N- alkyl-pyrroles and -indoles is to carry out these reactions under phase-transfer conditions (80JOC3172). For example, A-benzenesulfonylpyrrole is best prepared from pyrrole under phase-transfer conditions rather than by intermediate generation of the potassium salt (81TL4901). In this case the softer nature of the tetraalkylammonium cation facilitates reaction on nitrogen. The thallium salts of indoles prepared by reaction with thallium(I) ethoxide, a benzene-soluble liquid. 

Partly because of their low cost, aqueous solutions of sodium or potassium carbonate also are used for CO9 and H9S. Potassium bicarbonate has the higher solubility so the potassium salt is preferred. In view of the many competitive amine and carbonate plants that are in operation, fairly close figuring apparently is required to find an economic superiority, but other intangibles may be involved. 

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. 

The majority of aromatic sulphonic acids aie very soluble in water, and are difficult to obtain in the crystalline form On the other hand, the sodium or potassium salts generally ciystal-lise well, and it is customary to prepare them by pouiing the sulphonic acid directly after sulphonation into a strong solution of sodium or potassium chloride (Gattermann). 

When Sommer tried to prepare the potassium salt of 3 the crystal-fine product obtained exploded with violence as he spread it upon a porous plate. The potassium salt was, however, isolated and analyzed by Browne and Hoel. It is anhydrous but very soluble in water. Several other salts have been prepared. The slightly soluble heavy-metal salts are very sensitive to shock and may explode violently even under water. 

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