Bromine disulphide

Carbon disulphide is an excellent solvent for fats, oils, rubber, sulphur, bromine and iodine, and is used industrially as a solvent for extraction. It is also used in the production of viscose silk, when added to wood cellulose impregnated with sodium hydroxide solution, a viscous solution of cellulose xanthate is formed, and this can be extruded through a fine nozzle into acid, which decomposes the xanthate to give a glossy thread of cellulose. 

Like bromine, iodine is soluble in organic solvents, for example chloroform, which can be used to extract it from an aqueous solution. The iodine imparts a characteristic purple colour to the organic layer this is used as a test for iodine (p. 349). NB Brown solutions are formed when iodine dissolves in ether, alcohol, and acetone. In chloroform and benzene a purple solution is formed, whilst a violet solution is produced in carbon disulphide and some hydrocarbons. These colours arise due to charge transfer (p. 60) to and from the iodine and the solvent organic molecules. 

The mono-bromination of phenol at low temperatures in carbon disulphide or carbon tetrachloride solution results in almost exclusive para substitution ... 

Tris trifluoromethyl phosphine bums in air, but, unlike its methyl analogue, has not so far been found to form addition compounds with sulphur, carbon disulphide or silver iodide. With chlorine it forms the addition compound P(CF3)3Cl2 (b.p. 94°), and there is some indication that an addition compound of lower stability may be formed with bromine. With either of these halogens at higher temperatures, partial replacement of CF3 by halogen occurs and a similar reaction occurs with iodine, yielding some P(CF3)2l and P(CF3)l2. 

The increase in the solubility of bromine in soln. of ammonium salts is very marked, as is also the case with the alkali chlorides. The case with the alkali bromides is specially interesting. The solubilities by F. P. Worley are indicated in Table IX. The marked increase in the solubility of bromine in soln. of potassium bromide was attributed by M. Roloff to the formation of molecules of KBr3. He shook up a soln. of bromine in carbon disulphide with water and with an aq. soln. of potassium biomide, and measured the concentration of the bromine in the two layers. M. Wildermann has shown that the density of bromine vapour over a soln. of potassium bromide sat. with bromine is the same as over water sat. with bromine, indicating that the cone, of the free bromine in all the aq. soln. is the same, and any excess in the presence of potassium bromide must be united with the potassium bromide. All the bromine dissolved by a soln. of potassium bromide can be removed... 

A soln. of twenty-two grains of iodine and thirty-three grains of iodide of potassium, in one ounce of distilled water forms the liquor iodi of the British Pharmacopoeia. The effects produced by the ammonium salts are attributed to their hydrolysis into ammonium hydroxide, and the consequent formation of ammonium iodide or polyiodide. The effects produced by soln. of the halide salts are doubtless due to the formation of poly iodides as in the analogous case with bromine and potassium bromide. A. A. Jakowkin allowed carbon disulphide to remain in contact with aq. soln. of iodine and potassium iodide until equilibrium was attained and... 

Pour several drops of bromine water into a test tube, dilute it with 5 ml of distilled water, and add 5-10 drops of chloroform. Thoroughly stir the contents of the test tube. Explain the observed phenomenon. Perform a similar experiment with other organic solvents (petrol, benzene, carbon disulphide, carbon tetrachloride). 

Carbon disulphide vapour mixed with hydrogen and directed on to heated platinum reacts to form carbon and hydrogen sulphide.11 Carbon disulphide inflames in the cold in contact with fluorine, and under varying conditions it reacts with chlorine, bromine and iodine. 

In the absence of alkali, oxidation, as for instance by permanganate solution, bromine water, or nitric or iodic acid, involves the separation of sulphur.3 Water and aqueous alkalis hydrolyse carbon disulphide at 150° C., thus ... 

Carbon Bromosulphide, C2S3Br6.—When a mixture of carbon disulphide and bromine is allowed to stand and is then distilled, a residue of composition CS2Br4 is obtained this is decomposed by water or alcohol, forming sulphur bromide and carbon bromosulphide, C2S3Br6. Carbon bromosulphide when heated gives rise to bromine, sulphur bromide, carbon tetrabromide and a blue substance of apparent composition C9S4Br4.2HgO.11... 

Thiocyanogen, (CNS)2.—Thiocyanogen was first obtained by Soderback by the action of bromine or iodine on a suspension of the thiocyanate of silver, lead, cadmium, mercury, zinc, thallium or copper in carbon disulphide 3... 

Selenium Monobromide, Se2Br2.—This is produced together with the tetrabromide by the action of boiling bromine on selenium.9 The reaction, which is accompanied by considerable heat evolution, may be moderated by dissolving the bromine in carbon disulphide.10 The substance can also be produced by treating the tetrabromide with selenium at the ordinary temperature.11... 

It is a very deep red liquid having a density of 3-60 at 15° C. its odour is unpleasant. It is soluble in carbon disulphide and in chloroform and is, in its turn, a solvent for selenium. When heated, partial decomposition occurs, with formation of bromine and the tetrabromide, distillation taking place at 225° C. 

Selenium Tetrabromide, SeBr4, is formed by the action of excess of bromine on selenium or on selenium monobromide, the latter preferably being in solution in carbon disulphide, in order to moderate the vigour of the process.3... 

A dark red, almost black liquid, of specific gravity 2.97 to 2.99, and boiling at 63° C. Bromine dissolves in about 30 parts of water. It is easily soluble in alcohol, ether, chloroform, and carbon disulphide. 

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