Hydrogen chloride selenium dioxide

OXU3ATIVE Hydrogen peroxide. Hydrogen peroxide-Selenium dioxide. Lead tetraacetate. Photolytic Cuprous chloride. 

Phenanthrenequinone has been prepared by treatment of phe-nanthrene with chromic acid in acetic acid 5 potassium dichromate in sulfuric acid 3-6 hydrogen peroxide in acetic acid 6 7 and selenium dioxide above 250°.8 It can also be prepared from benzil with aluminum chloride at 120° 9 and from biphenyl-2,2 -dialdehyde with potassium cyanide.10... 

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. 

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. 

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... 

Iron diselenide, FeSe2, is prepared by heating anhydrous ferric chloride to dull red heat in hydrogen selenide.3 When ignited in oxygen, it yields ferric oxide and selenium dioxide. 

Cyclopenteaediol isomers have previously been prepared by hydrolysis of acetates produced by reaction of dibromocyclopen-tene with potassiiun acetate in acetic acid by reaction of cyclo-pentene with selenium dioxide in acetic anhydride or by reaction of cyclopentadiene with phenyl iodosoacetate/ with lead tetraacetate, or with peracetic acid in the absence of base. Preparation of cydopentenediol without intermediate formation of acetates has been accomplished by reaction of cyclopentadiene with hydrogen peroxide in the presence of osmium tetroxide in terf-butanol, and hy reaction of cyclopentadiene with peracetic acid in a methylene chloride suspension of anhydrous sodium carbonate, followed by hydrolysis of the resulting epoxycyclo-pentene. ... 

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