Solubility anhydrous compounds

Since the lanthanides that exhibit the divalent state in aqueous solution, Sm, Eu ", and Yb, are all readily oxidized to the trivalent state, attempts to record their absorption spectra have usually proceeded from the rapid dissolution of a soluble anhydrous compound. The absorption spectra shown in fig. 24.16 for Sm ", Eu, and Yb were adapted from results published by Butement and Terrey (1937), Butement (1948), and Christensen et al. (1973). Production of other divalent lanthanide ions by pulse radiolysis, and the observation of their spectra is discussed in section 5.2. 

By treatment with anhydrous aluminium chloride (Holmes and Beeman, 1934). Ordinary commercial, water-white benzene contains about 0 05 per cent, of thiophene. It is first dried with anhydrous calcium chloride. One litre of the dry crude benzene is shaken vigorously (preferably in a mechanical shaking machine) with 12 g. of anhydrous aluminium chloride for half an hour the temperature should preferably be 25-35°. The benzene is then decanted from the red liquid formed, washed with 10 per cent, sodium hydroxide solution (to remove soluble sulphur compounds), then with water, and finally dried over anhydrous calcium chloride. It is then distilled and the fraction, b.p. 79-5-80-5°, is collected. The latter is again vigorously shaken with 24 g. of anhydrous aluminium chloride for 30 minutes, decanted from the red liquid, washed with 10 per cent, sodium hydroxide solution, water, dried, and distilled. The resulting benzene is free from thiophene. 

The anhydrous compound is not appreciably hygroscopic, is readily soluble in acetone and amyl alcohol, and insoluble in benzene, toluene, xylene and chloroform it is also readily soluble in absolute methyl or ethyl alcohol, but a trace of water causes immediate hydrolysis with the formation of an opalescent precipitate. 

Step 4. The steam-volatile neutral compounds. The solution (containing water-soluble neutral compounds obtained in Step 1 is usually very dilute. It is advisable to concentrate it by distillation until about one-third to one-half of the original volume is collected as distillate the process may be repeated if necessary and the progress of the concentration may be followed by determination of the densities of the distillates. It is frequently possible to salt out the neutral components from the concentrated distillate by saturating it with solid potassium carbonate. If a layer of neutral compound makes its appearance, remove it. Treat this upper layer (which usually contains much water) with solid anhydrous potassium carbonate if another aqueous layer forms, separate the upper organic layer and add more anhydrous potassium carbonate to it. Identify the neutral compound. 

Stabihty depends mosdy on purity, with purer materials having longer shelf Hves (1). For the higher alkyl groups, the anhydrous compounds are soluble and the monohydrates are insoluble in ether. Solutions in water are strongly ionized and acidic. The lower dialkyl sulfates are Hquids with faint but pleasant odors n-nonyX and higher normal aHphatic and cycHc sulfates are soHds. 

Elemental composition Cr 32.84%, Cl 67.16%. Chromium(HI) chloride may be solubilized in water by a reducing agent and the aqueous solution may be analyzed for chromium by AA, ICP, or other instrumental techniques. Alternatively, the compound may be digested with nitric acid, brought into aqueous phase, diluted appropriately, and analyzed for the metal as above. The aqueous solution (when a nonchloride reducing agent is used for dissolution of the anhydrous compound in water) may be analyzed for chloride ion by ion chromatography or chloride-selective electrode. The water-soluble hexahydrate may be measured in its aqueous solution as described above. 

The anhydrous compound is white crystalline powder hygroscopic density 1.70 g/cm3 converts to sodium pyrophosphate at 240°C soluble in water ... 

Tellurium(IV) sulfato complexes of composition 2(2Te02 S03),MHS04-2H20 have been reported,46 from which the anhydrous compounds were obtained by calcination. Carboxylic acids have also been found to form anionic complexes with tellurium(IV) and polonium(IV). For example, the silver salts of the citrato- and tartrato-tellurates(IV) have been described47 as insoluble in water but soluble in nitric acid. 

Hydrocellulose is formed when pure cellulose is subjected to the action of cold mineral acids solutions. Hydrolysis then proceeds by stages to yield glucose as the final product. It is possible to stop the hydrolysis at any desired moment, for example by diluting the reaction mixture with water. Hydrocellulose then remains in the form of non dissolved fibres or as powder (Girard [47]). The hydrolysis is usually performed by means of hydrochloric acid or with hydrogen chloride in an anhydrous medium. In the latter case, a water-soluble addition compound (C6H10O5)2.3HCl may occur as a transient product, as reported by Hess and M. Ullman [48]. 

Cobalt Metaphosphate, Co(P03)2, is obtained9 by evaporating a mixture of cobalt sulphate and phosphoric acid in a platinum dish, and subsequently heating to 300° C. It is deposited as a beautiful, rose-coloured, anhydrous compound, insoluble in water and dilute acids, but soluble in concentrated sulphuric acid. 

The synthesis of nickel organic compounds often requires a source of organic-solvent-soluble anhydrous nickel halide. 

The evidence from microstructure, calorimetry and other sources suggests that the hydration processes of cement and C3S are essentially similar. There are important differences in the nature of the early product and in where the C-S-H formed in the middle stage of reaction begins to deposit, but in both cases it would appear that the early reaction slows down because of the deposition of a layer of product, which either isolates parts of the anhydrous surfaces from the main solution or allows the concentrations close to those surfaces to rise to values approaching the theoretical solubilities of the anhydrous compounds. In both cases, the initiation of the main reaction and the kinetics in its acceleratory phase appear to be controlled by the nucleation and growth of C-S-H. 

Iron(If) bromide, FeBr2 (ferrous bromide), is a pale yellow/brown hygroscopic solid soluble in water and donor organic solvents. It may be prepared from iron and bromine at 200 °C, or iron and HBr in methanol, hydrobromination of iron(III) oxide at 200-350 °C, or dehydration of [FeBr2(H20)4]. The anhydrous compound is readily purified from FeBr3 by sublimation under nitrogen or in vacuo. It... 

The compound is sufficiently volatile so that it may be purified by sublimation in vacuo. It is quite hygroscopic. It is very soluble in benzene, carbon tetrachloride, and chloroform the reported low solubility in benzene may refer to the diaquo compound. The anhydrous compound can be precipitated from benzene by ether, probably as an ether addition compound. Solutions air-o.xidize at a rate inversely related to the donor properties of the solvent. Magnetic moments ranging from 3.9 to 4.93 B.M. have been found the high value is probably the most accurate. ... 

The monosulphide and polysulphides are formed by burning the metals in sulphur vapour, by the action of sulphur on the metals dissolved in liquid ammonia, and by the action of the molten metals on sulphur dissolved in toluene. Hydrates or alcoholates and, in some cases, the anhydrous compounds may be prepared by dissolving sulphur in hot solutions of the hydrosulphides or monosulphides. Potassium, rubidium and caesium give all the sulphides where = 1, 2, 3, 4, 5, or 6 sodium only up to the pentasulphide, and lithium only those for which x = 1, 2 and 4 (Pearson and Robinson, 1931). All the metals form two polysulphides of relatively outstanding stability one is invariably the disulphide, and the other tetrasulphide in the case of lithium or sodium, and pentasulphide in the case of potassium, rubidium or caesium. The amount of water of crystallisation and the solubility decrease with increase in atomic number of the metal, the gradation being most marked between sodium and potassium. 

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