Hydrous

The JP 2001 describes hydrous lanolin as a mixture of lanolin and 25-30% w/w purified water. The PhEur 2005 describes hydrous lanolin as a mixture of lanolin and 25% w/w purified water see also Section 18. The PhEur 2005 additionally permits the inclusion of up to 150 ppm of butylated hydroxy-toluene as an antioxidant. 

Hydrous lanolin is widely used in topical pharmaceutical formulations and cosmetics in applications similar to those for lanolin. 

Hydrous lanolin is commonly used in the preparation of water-in-oil creams and ointments. More water may be incorporated into hydrous lanolin than into lanolin. 

Hydrous lanolin is a pale yellow-colored, unctuous substance with a faint characteristic odor. When melted by heating on a water bath, hydrous lanolin separates into a clear oily layer and a clear water layer. 

Solubility practically insoluble in chloroform, ether, and water. Only the fat component of hydrous lanolin is soluble in organic solvents. 

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Matijevi i E 1976 Preparation and oharaoterization of monodispersed metal hydrous oxide sols Prog. Colloid Polym. Sol. 61 24-35... 

Scandium is not an uncommon element, but is difficult to extract. The only oxidation state in its compounds is -I- 3, where it has formally lost the 3d 4s electrons, and it shows virtually no transition characteristics. In fact, its chemistry is very similar to that of aluminium (for example hydrous oxide SC2O3, amphoteric forms a complex [ScFg] chloride SCCI3 hydrolysed by water). 

Alkali metal ferrates(VI), for example K2pe04, are obtained by oxidation of a suspension of hydrous iron(III) oxide (assumed to be Fe(OH)3 in the equation below) by chlorate(I) in concentrated alkali ... 

Metal organic decomposition (MOD) is a synthesis technique in which metal-containing organic chemicals react with water in a nonaqueous solvent to produce a metal hydroxide or hydrous oxide, or in special cases, an anhydrous metal oxide (7). MOD techniques can also be used to prepare nonoxide powders (8,9). Powders may require calcination to obtain the desired phase. A major advantage of the MOD method is the control over purity and stoichiometry that can be achieved. Two limitations are atmosphere control (if required) and expense of the chemicals. However, the cost of metal organic chemicals is decreasing with greater use of MOD techniques. 

Hexafluoroantimonic acid [72121 -43-8] HSbF 6H20, is prepared by dissolving freshly prepared hydrous antimony pentoxide ia hydrofluoric acid or adding the stoichiometric amount of 70% HF to SbF. Both of these reactions are exothermic and must be carried out carefully. 

FIuorosihca.tes, Compared to the simple sUicates, these crystals have more complex chain and sheet stmctures. Examples from nature iaclude hydrous micas and amphiboles, including hornblende and nephrite jade. In glass-ceramics, fluorine replaces the hydroxyl ion fluorine is much easier to iacorporate ia glass and also makes the crystals more refractory. Eour commercial fluorosUicate glass-ceramic compositions and thek properties are Usted ia Table 2. 

Fluorozirconate Crystallization. Repeated dissolution and fractional crystallization of potassium hexafluorozirconate was the method first used to separate hafnium and zirconium (15), potassium fluorohafnate solubility being higher. This process is used in the Prinieprovsky Chemical Plant in Dnieprodzerzhinsk, Ukraine, to produce hafnium-free zirconium. Hafnium-enriched (about 6%) zirconium hydrous oxide is precipitated from the first-stage mother Hquors, and redissolved in acid to feed ion-exchange columns to obtain pure hafnium (10). 

Hafnium dioxide is formed by ignition of hafnium metal, carbide, tetrachloride, sulfide, boride, nitride, or hydrous oxide. Commercial hafnium oxide, the product of the separation process for zirconium and hafnium, contains 97—99% hafnium oxide. Purer forms, up to 99.99%, are available. 

The hydrous oxide, Hf02 xH20, is precipitated from acidic solutions by addition of ammonium hydroxide or dilute alkaline solutions. However, the hydrous oxide exhibits a limited solubihty in strongly alkaline solutions (65). The existence and relative stabiUty of soluble alkaline peroxy compounds has been demonstrated (66). 

The best known oxoanion of iron is the ferrate(VI) prepared by oxidizing a suspension of hydrous iron(III) oxide in concentrated alkah with potassium hypochlorite or by anodic oxidation of iron in concentrated alkah. Crystals of potassium ferrate [13718-66-6], K FeO, are deep purple, orthorhombic, and contain discrete tetrahedral [FeOJ anions. Barium ferrate [13773-23A] can be precipitated from solutions of soluble ferrate salts. 

The quantities of magnesium sulfate (anhydrous and hydrous) shipped and used in the United States during the period 1989—1993 were (52,103,130) ... 

The Mn ion is so unstable that it scarcely exists in aqueous solution. In acidic aqueous solution, manganic compounds readily disproportionate to form Mn ions and hydrated manganese(IV) oxide, Mn02 2H20 in basic solution these compounds hydroly2e to hydrous manganese(III) oxide, MnO(OH). Sulfuric acid concentrations of about 400 450 g/L are required to stabilize the noncomplexed Mn ion in aqueous solutions. 

Fig. 2. Hydration of the surface stmcture of manganese dioxide (2) and subsequent reactions of hydrous manganese oxide (3) showing proton transfer (4)...

Ion Ionic radius, pm CoUoidal hydrous manganese dioxide, mol/mol Hydrated radius, pm 5-Mn02, )J.mol/g... 

Figure 17 summarizes the avadable sol—gel processes (56). The process on the right of the figure involves the hydrolysis of metal alkoxides in a water—alcohol solution. The hydrolyzed alkoxides are polymerized to form a chemical gel, which is dried and heat treated to form a rigid oxide network held together by chemical bonds. This process is difficult to carry out, because the hydrolysis and polymerization must be carefully controlled. If the hydrolysis reaction proceeds too far, precipitation of hydrous metal oxides from the solution starts to occur, causing agglomerations of particulates in the sol. 

A gel is defined as a hydrous metal aluminosihcate prepared from either aqueous solutions, reactive soflds, colloidal sols, or reactive aluminosihcates such as the residue stmcture of metakaolin and glasses. 

Uranium Purification. Subsequent uranium cycles provide additional separation from residual plutonium and fission products, particularly zirconium— niobium and mthenium (30). This is accompHshed by repeating the extraction/stripping cycle. Decontamination factors greater than 10 at losses of less than 0.1 wt % are routinely attainable. However, mthenium can exist in several valence states simultaneously and can form several nitrosyl—nitrate complexes, some for which are extracted readily by TBP. Under certain conditions, the nitrates of zirconium and niobium form soluble compounds or hydrous coUoids that compHcate the Hquid—Hquid extraction. SiUca-gel adsorption or one of the similar Hquid—soHd techniques may also be used to further purify the product streams. 

A. K. Burnham, Relationship Between Hydrous and Ordinay Pyrolysis, UCRL-JC-114130, Lawrence Livermore National Laboratory, Livermore, Calif.,... 

The petroleum generation process can be dupHcated by laboratory pyrolysis. Higher temperatures are needed to produce these reactions in a few hours or days rather than the millions of years in nature (16,17). Both dry pyrolysis and hydrous pyrolysis have been used. 

In the double-neutralization process, Na2SiFg is precipitated and removed by filtration at a pH of 3—4 (9). Upon raising the pH to 7—9, insoluble phosphates of Fe, Al, Ca, and Mg form and separate. Iron can be precipitated as hydrous ferric oxide, reducing the phosphate loss at the second filter cake. Both the fluorosihcate and metal phosphate filter residues tend to be voluminous cakes that shrink when dewatered recovery of soluble phosphates trapped within the cakes is difficult. 

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