Selenium oxychloride

Seiko Chemical Co., Ltd, 188 Selenium and Selenium Compounds, 115 Selenium dioxide, 116 Selenium hexafluoride, 116 Selenium oxychloride, 116 Selenium sulfides, 116... 

Diamino-2,l,3-benzothiadiazole 82 affords [l,2,5]selenodiazolo[3,4-i ]-2,l,3-benzothiadiazole 83 quantitatively on treatment with selenium oxychloride in refluxing chloroform-pyridine <2004JHC955>. This was an improvement of the previous method using selenium dioxide (62% yield) <1984ZNB485>. 6-Isoprenyl-477-imidazo[4,5-< ]-benzothiadiazolone 84 was obtained when 4,5-diaminobenzothiadiazole was reacted with methyl acetoacetate in xylene at reflux (Scheme 10) <1997H(45)19>. 

SELENIUM TETRACHLORIDE SELENIUM HEXAFLUORIDE SELENIUM OXYCHLORIDE SELENIUM DIOXIDE SILICON... 

SeOCl2 SELENIUM OXYCHLORIDE -31.1449 -1.5960E+03 1.5901E+01 -1.1690E-02 3.7904E... 

There are several different compounds of selenium and the halogen chlorine that range from selenium dichloride (SeCy to selenium oxychloride (SeOCl ), which are used as solvents. 

Compounds Selenium dioxide selenium trioxide selenium oxychloride sodium selenite sodium selenate hydrogen selenide selenic acid selenium sulfide selenium disulfide... 

Elemental selenium is not particularly irritating, but various compounds such as selenium oxychloride and selenium dioxide are strong vesicants. Skin contact with the fume of heated selenium dioxide caused an acute, weeping dermatitis, with the development of hypersensitivity in some cases. Selenium dioxide forms selenious acid when in contact with water if allowed to penetrate beneath the fingernails, it causes an especially painful inflammatory reaction. ... 

Se02 + HBr SeOBr2 + H2O Reaction with thionyl chloride yields selenium oxychloride ... 

Selenium oxychloride is a solvent for synthetic phenohc resins and many other substances. 

Selenium oxychloride may be prepared by several methods (1) by passing chlorine gas into a suspension of selenium dioxide in carbon tetrachloride, (2) by heating thionyl chloride, SOCE, with selenium dioxide, (3) by dehydration of dichloroselenious acid, H2Se(CE)02, and (4) by fusion of selenium dioxide, selenium, and calcium chloride. 

The known dibromide 464 was converted in good yield to the dinitrile 465 by reaction with buffered potassium or sodium cyanide. Reaction of 2,5-dimethoxycarbonyl-3,4-dicyanomethylthiophene 465 with thionyl chloride and selenium oxychloride gave thieno[3,4-f]thiophene 466 and selenolo[3,4-f]thiophene 467, respectively (Scheme 57) <2002JOC2453>. In the case of thionyl chloride as the sulfur transfer reagent, an intermediate sulfoxide 468 must be involved, which then suffers a spontaneous base-catalyzed Pummerer reaction to give 466 in high yield. 

The ease with which selenium combines with many other elements to form binary compounds has already been mentioned (p. 299). Only one compound with hydrogen is known, but a series of polyselenides of the alkali metals corresponding to the polysulphides has been obtained. Selenium forms a hexafluoride, SeFG, but no other hexalialide has been isolated. The tetrahalides arc the most stable, and mixed chloro-bromides of quadrivalent selenium, SeCl Br, are known. Selenium monochloride, SeaCla, and selenium monobromide, Se2Br2, also exist as comparatively stable liquids at ordinary temperatures. No compound of selenium and iodine is known. Selenium oxychloride, SeOCl2, and the oxybromide, SeOBr2, are extremely reactive and useful compounds. 

Selenyl Chloride, Selenium Oxychloride, SeOCl2, may be prepared in the following ways ... 

By adding the calculated amount of dry selenium dioxide to selenium tetrachloride suspended in carbon tetrachloride. The oxychloride formed in the cold dissolves in the carbon tetrachloride, from which it may be obtained by distillation. Carbon tetrachloride distils at 76° to 77° C., while the selenium oxychloride distils over at 176-4° C.1... 

When a mixture of selenium dioxide and selenium tetrachloride is heated in a sealed tube, selenium oxychloride is formed 5... 

Selenium oxychloride is also formed when selenium dioxide is heated with sodium chloride 6... 

Selenium oxychloride is a nearly colourless liquid having a boiling-point of 176-4° C. at 726 mm. Its melting-point is 10 8° C.7 At 20° C. it has a refractive index of 1-6516. The specific conductivity of the dry liquid at 25° C. is 8 2-0 ( 0-3) x 10 5 mho. The oxychloride is, however, extremely hygroscopic, and the presence of traces of water causes a considerable increase in the electrical conductivity. The presence of the merest trace of water can be shown 9 by sealing up a sample of the oxychloride with cobalt carbonate which has been dried at 200° C. for three hours a blue colour gradually develops if moisture is present. 

Selenium oxychloride absorbs all light up to a wave-length of 4050pp. It is miscible with chloroform, carbon disulphide and benzene without chemical change. It is also soluble in carbon tetrachloride, but after a time reaction takes place with formation of selenium tetrachloride and carbonyl chloride.10 At the ordinary temperatures selenium oxychloride is not miscible with the paraffin hydrocarbons,... 

Selenium oxychloride, when distilled under reduced pressures, has a light straw colour, but when distilled under atmospheric pressure it decomposes slightly and becomes reddish-brown this decomposition reverses to some extent on cooling. 

The vapour pressure of selenium oxychloride has been determined at temperatures between 84-3° and 117-2° C. It can be expressed by the formula 2... 

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