Sulphur solubility

By rapidly cooling the fluid mixture it is possible to minimise the readjustment of the equilibrium and to attain a solid condition in which tire original proportions of the mixture are approximately retained in the solid state tire allotropic change is so very slow as to allow careful and fairly prolonged examination of the mixture. It is then found that, the normal mobile liquid constituent (S ) has given rise to crystalline sulphur, soluble in carbon disulphide, whereas the dark-coloured viscous constituent (S ) has produced an amorphous solid, insoluble in this solvent4 (see also p. 10). A rough analysis of molten sulphur in... 

Insoluble Amorphous Sulphur is produced, usually together with some sulphur soluble in carbon disulphide, by many reactions in which sulphur is set free. The slow decomposition of sulphur chloride or bromide by water, which may require several days for completion, gives a very stable form of insoluble sulphur.8 The action of mineral acids on... 

TT-Sulphur, a deep yellow amorphous form of sulphur soluble in carbon disulphide, has already been described (p. 17). 

With increasing fQ the sulphur solubility in silicate melts decreases according to (25) before increasing again as reaction (26) becomes effective with sulphur dissolving as S0 ,... 

On acetylation it gives acetanilide. Nitrated with some decomposition to a mixture of 2-and 4-nitroanilines. It is basic and gives water-soluble salts with mineral acids. Heating aniline sulphate at 190 C gives sulphanilic add. When heated with alkyl chlorides or aliphatic alcohols mono- and di-alkyl derivatives are obtained, e.g. dimethylaniline. Treatment with trichloroethylene gives phenylglycine. With glycerol and sulphuric acid (Skraup s reaction) quinoline is obtained, while quinaldine can be prepared by the reaction between aniline, paraldehyde and hydrochloric acid. 

C2He04S, Et0)(H0)S02. Oily acidic liquid. Soluble in water and slowly hydrolysed by it to ethanol and sulphuric acid. Prepared by passing ethene into concentrated sulphuric acid or by heating ethanol and sulphuric acid. Gives ethene when heated alone, and diethyl sulphate when heated with ethanol at 140 C. Forms crystalline metallic salts which are soluble in water. 

C, soluble in water and alcohol. It occurs in woad as the glucoside indican, and in mammalian urine, combined with sulphuric acid, as an ester, also called indican. It arises in the body from the bacterial decomposition of tryptophan. 

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. 

M.p. 283 C (decomp.). Soluble in water and alcohol. The naturally occurring substance is laevorotatory. Methionine is one of the natural sulphur-containing amino-acids, and is present in small quantities in the hydrolysis pro-... 

The phthalocyanines must be suitably dis-p>ersed to be used as pigments or they can be sulphonated to water-soluble forms for dyeing and for precipitation as lakes. The dispersion is carried out by solution in sulphuric acid, followed by precipitation in water. 

Protamines. Strongly basic, low mol. wt. proteins which contain high levels of arginine, but no sulphur-containing amino-acids. They are soluble proteins, associated with nucleic acids and are obtained in large quantity from fish spermatozoa. 

Boron trioxide is not particularly soluble in water but it slowly dissolves to form both dioxo(HB02)(meta) and trioxo(H3B03) (ortho) boric acids. It is a dimorphous oxide and exists as either a glassy or a crystalline solid. Boron trioxide is an acidic oxide and combines with metal oxides and hydroxides to form borates, some of which have characteristic colours—a fact utilised in analysis as the "borax bead test , cf alumina p. 150. Boric acid. H3BO3. properly called trioxoboric acid, may be prepared by adding excess hydrochloric or sulphuric acid to a hot saturated solution of borax, sodium heptaoxotetraborate, Na2B407, when the only moderately soluble boric acid separates as white flaky crystals on cooling. Boric acid is a very weak monobasic acid it is, in fact, a Lewis acid since its acidity is due to an initial acceptance of a lone pair of electrons from water rather than direct proton donation as in the case of Lowry-Bronsted acids, i.e. 

Lead dioxide is slightly soluble in concentrated nitric acid and concentrated sulphuric acid, and it dissolves in fused alkalis. It therefore has amphoteric properties, although these are not well characteri.sed since it is relatively inert. 

Industrially. phosphoric(V) acid is manufactured by two processes. In one process phosphorus is burned in air and the phos-phorus(V) oxide produced is dissolved in water. It is also manufactured by the action of dilute sulphuric acid on bone-ash or phosphorite, i.e. calcium tetraoxophosphate(V). Ca3(P04)2 the insoluble calcium sulphate is filtered off and the remaining solution concentrated. In this reaction, the calcium phosphate may be treated to convert it to the more soluble dihydrogenphosphatc. CafHjPOjj. When mixed with the calcium sulphate this is used as a fertiliser under the name "superphosphate . 

When sulphur is melted viscosity changes occur as the temperature is raised. These changes are due to the formation of long-chain polymers (in very pure sulphur, chains containing about 100 (X)0 atoms may be formed). The polymeric nature of molten sulphur can be recognised if molten sulphur is poured in a thin stream into cold water, when a plastic rubbery mass known as plastic sulphur is obtained. This is only slightly soluble in carbon disulphide, but on standing it loses its plasticity and reverts to the soluble rhombic form. If certain substances, for example iodine or oxides of arsenic, are incorporated into the plastic sulphur, the rubbery character can be preserved. 

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. 

Barium sulphite is soluble in dilute hydrochloric acid unlike barium sulphate which is insoluble. Hence this reaction, and the evolution of sulphur dioxide on addition of an acid, distinguishes a sulphite from a sulphate. 

Sulphur trioxide is not very soluble in water but dissolves readily in concentrated sulphuric acid. 

This reaction is also used on a large scale, to obtain iodine from seaweed. The ash from burnt seaweed ( kelp ) is extracted with water, concentrated, and the salts other than iodides (sulphates and chlorides) crystallise out. The more soluble iodides remain and the liquor is mixed with sulphuric acid and manganese dioxide added the evolved iodine distils off and is condensed. 

Anhydrous titanium dioxide is only soluble with difficulty in hot concentrated sulphuric acid dilution allows the crystallisation of a sulphate of formula T10S04.H20, but it is doubtful if the titanyl cation TiO actually exists, either in solution or the solid. Certainly [TifHjOIn] does not exist, and solutions of titanyl salts may best be considered to contain ions [Ti(0H)2(H204)] . Titanium... 

A second preparation to illustrate sulphonation is that of sulphanilic acid, NH2C4H4SO3H, a highly crystalline substance which, having a low solubility in cold water, can be readily isolated. If aniline is treated with an excess of concentrated sulphuric acid, aniline hydrogen sulphate is first formed, and... 

Both chloramine-T and dichloramine-T have marked antiseptic properties, chloramine-T being most frequently used because of its solubility in water. Aqueous solutions of chloramine-T can be used either for external application, or for internal application to the mouth, throat, etc, as chloramine-T in moderate quantities is non-toxic its aqueous solution can also be effectively used when the skin has come in contact with many of the vesicant liquid poison-gases, as the latter are frequently organic sulphur or arsenic derivatives which combine with or are oxidised by chloramine-T and are thus rendered harmless. 

To determine which halogen is present, take 1-2 ml. of the filtrate from the sodium fusion, and add dilute sulphuric acid until just acid to litmus. Add about 1 ml. of benzene and then about 1 ml. of chlorine water and shake. A yellowish-brown colour in the benzene indicates bromine, and a violet colour iodine. If neither colour appears, the halogen is chlorine. The result may be confirmed by testing the solubility of the silver halide (free from cyanide) in dilute ammonia solution silver chloride is readily soluble, whereas the bromide dissolves with difficulty, and the iodide not at all. 

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