Selenium hydrogen chloride

J. R. Joss 19 seems to have obtained this element in 1824 he noticed that a red colour was developed in preparing hydrogen chloride by heating a sample of rock salt with sulphuric acid, but he attributed the coloration to the presence of selenium in the acid employed. J. Volhard also narrates that J. von Liebig had bromine in hand a month before A. J. Balard, but mistook it for iodine chloride ... 

Colloidal selenium produced by means of hydrazine hydrate can be frozen to a blue ice which melts with complete coagulation, but the presence in the solution of hydrogen chloride, sodium carbonate or potassium chloride, exerts a protective action which is a maximum at certain definite concentrations.2... 

Estimation of Selenium in Sulphide Minerals.s—In various sulphite-cellulose manufactories difficulties have occurred which have been traced to the presence of selenium in the pyrites used for burning. Part of the selenium remains in the burnt pyrites and part volatilises with the sulphur dioxide. 20 to 30 grams of pyrites are dissolved in hydrochloric acid (dens.=1-19) and potassium chlorate. Zinc is added to reduce the iron to the ferrous condition more hydrochloric acid is then added, the solution boiled and stannous chloride added to precipitate selenium. Since the selenium may contain arsenic, it is collected on an asbestos filter, dissolved in potassium cyanide and reprecipitated using hydrogen chloride and sulphur dioxide. The element may then be estimated by the iodometric method described below. In order to determine the relative proportion of volatile to non-volatile selenium, the pyrites may be roasted in a current of oxygen. After this treatment the contents of the tube are dissolved in warm potassium cyanide and the selenium reprecipitated and estimated in the ordinary way. 

A solution of selenium in fuming sulphuric acid gives a gradual separation of the monoehloride on the addition of hydrogen chloride.6... 

By various methods from selenium dioxide for example, by the action of hydrogen chloride, thionyl chloride or phosphorus pentachloride. The last-named is perhaps the most convenient chlorinating agent. A mixture of the pentachloride and the dioxide is heated until chemical change causes it to solidify. Phosphorus oxychloride can be distilled off with the aid of a current of carbon dioxide and the residual selenium tetrachloride purified by sublimation.8... 

This reaction may also be effected by mixing together the selenium dioxide and the dehydrating agent, passing in hydrogen chloride in the cold and then distilling off the oxychloride.4... 

Dry hydrogen sulphide interacts with selenium oxychloride with the formation of yellow selenium sulphide and evolution of hydrogen chloride. There is a development of heat which dissociates the selenium sulphide into sulphur and red selenium. Sulphur dioxide has no action on the hot anhydrous oxychloride, but if water is present there is a deposition of selenium. Sulphur trioxide is soluble in selenium oxychloride, forming a thick solution which is a very powerful solvent for the oxides of the rare earth metals. When the oxychloride is brought into contact with finely divided barium sulphate, the latter is at once peptised and becomes gelatinous in appearance,1 but when subsequently treated with water the sulphate immediately changes back to the ordinary form. 

Carbon monoxide has no action on selenium oxychloride.2 Water causes decomposition of the liquid into selenium dioxide and hydrogen chloride. Anhydrous ammonia reacts according to the equation. -... 

Chloroselenic Acid, (Se03.HGl)2, has been described as a pale yellow liquid obtained wrhen dry hydrogen chloride and selenium trioxide (see p. 331) are allowed to combine in a cooled vessel.1 It has a density of 2-26, and solidifies at —46° C. It fumes in air owing to the escape of hydrogen chloride, which gas is also evolved on heating, selenium and selenium dioxide remaining. 

By the action of hydrazine hydrate on a dilute solution of selenic acid, hydrazine hydrogen selenate may be obtained as a colourless compound which is not decomposed by boiling water, but which, when dry, explodes with great readiness when subjected to heat, to shock, or to fumes of hydrogen chloride. For this reason, before hydrazine hydrate is used in the analysis of selenium compounds (see p. 307), it is essential that selenic acid and selenates should be reduced to selenites by means of hydrochloric acid.3... 

Benzene (3 parts) and one part of selenium tetrachloride are heated together under reflux in the presence of anhydrous aluminium chloride until no further evolution of hydrogen chloride occurs.3 Benzene, aluminium bromide and selenium bromide interact to give bromobenzene and a 22 to 27 per cent, yield of diphenyl selenide.4... 

Dibenzyl selenium dichloride,4 (C6H5.CH2)2SeCl2, occurs when an alcoholic solution of the dinitrate is treated with hydrogen chloride, or when benzylseleninic acid is treated with phosphorus pentachloride. It crystallises in colourless needles, M.pt. 134° to 135° C.5... 

Dibenzyl selenium dibromide, (C6H5.CH2)2SeBr2.6—The existence of this compound seems doubtful, but it is said to result when the hydrogen chloride in the foregoing preparation is replaced by hydrogen bromide. Dibenzyl selenide and bromine in chloroform yield a red powder of melting-point 84° C.7... 

The hydrogen chloride formed reacts with the selenium derivative giving a further amount of 3-chloroacetylacetone, and the principal reaction becomes modified with the production of a small amount of diselenium acetylacetone. 

Samarium (III) nitrate, analysis of anhydrous, 6 41 Selenic acid, crystalline, 3 137 Selenides, precipitation of pure metallic, from solutions of hydrogen selenide, 2 185 Selenium, red and gray, 1 119 Selenium (II) chloride, formation of, by selenium(IV) chloride, 6 127... 

Oxidation of 2,4,4-trimethyl - A1 -py rroline V-oxide with selenium dioxide, followed by treatment with hydrogen chloride, causes ringopening and reclosure to 2,3,4,5-tetrahydro-3,3-dimethyl-5-oxo-pyridine N-oxide (111). Clemmensen reduction of 111 forms 2,4,4-trimethyl-d 1-pyrroline (112) by ring-contraction.334... 

Hydrogen chloride converted bis[2-formylphenyltelluro] selenium quantitatively to 2-formylphenyl tellurium chloride2. 

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