Atmosphere carbon disulphide

A solution of sodium methoxide, prepared from sodium (23 g) and dry methanol (500 mL), was added drop-wise at 0 °C to a stirred suspension of aminoacetonitrile hydrochloride (18, 100 g, 1.08 mol) in dry methanol (100 rnL). After stirring for 2 h at rt the precipitated sodium chloride was filtered off and the filtrate concentrated in vacuo. EtOAc (20 mL) was added and evaporated under reduced pressure to remove all traces of methanol. The oily residue was dissolved in dry EtOAc (100 mL) and anhydrous sodium sulfate added. After cooling, the precipitate was filtered off. The solution of crude aminoacetonitrile was used without further purification. This solution was added drop-wise during a period of 1 h to a vigorously stirred, ice-cooled solution of carbon disulphide (100 mL, 1.66 mol) in dry EtOAc (100 mL) under an N2 atmosphere. Continued mechanical stirring and water-free conditions were essential. The mixture was stirred at 0 °C for 1 h. The resultant precipitate was filtered off, washed with EtaO and dried, giving the product 50 as yellow crystals (99 g, 75 % on amount of sodium), m.p. 131 °C dec. IR (KBr) v max 1630, 1500 cm. ... 

An air stream at approximately atmospheric temperature and pressure and containing a low concentration of carbon disulphide vapour is flowing at 38 m/s through a series of 50 mm diameter tubes. The inside of the tubes is covered with a thin film of liquid and both heat and mass transfer are taking place between the gas stream and the liquid film. The film heat transfer coefficient is found to be 100 W/mzK. Using a pipe friction chan and assuming the tubes to behave as smooth surfaces, calculate ... 

Salts of O-alkyldithiocarbonatcs ( xanthates ) are hazardous as dusts, forming explosive suspensions in air. The lower-alkyl salts are claimed to be explosive in the solid state when dry [1]. Explosions reported when drying hydrated xanthate salts are probably the consequence of release of carbon disulphide to form an inflammable atmosphere of very low autoignition temperature in the oven [2], Xanthate esters are thermally unstable by a variety of eliminations and rearrangements, all distinctly exothermic and many evolving extremely flammable gases and vapours. Free xanthic acids, which may be isolated on acidification, decompose autocatalytically and perhaps explosively [3],... 

Pour the dry carbon disulphide into a flask for distillation under atmospheric pressure (see Fig. 20) and distil it over the fused calcium chloride, collecting the fraction boiling at 45-46 °C. Heat with hot water in the absence of heating equipment. 

Crystallisation of sulphur at the ordinary temperature from solution, e.g. from carbon disulphide, yields octahedral crystals which differ from the crystals obtained by the solidification of molten sulphur in that the proportion of y- and 77-sulphur, present in solid solution, is less. Octahedral crystals of sulphur may be prepared at the ordinary temperature also by the gradual atmospheric oxidation of a. solution of... 

Carbon disulphide is an excellent solvent for rhombic sulphur, the proportions soluble in 100 parts by weight of the solvent at different temperatures being given in the following table the highest temperature is the boiling-point of the saturated solution under ordinary atmospheric pressure.4... 

Carbon disulphide vapour appears to be associated to a small extent. When the vapour and ether vapour are mixed at constant volume at 80° C. under atmospheric pressure, the increase of pressure observed indicates previous association of the carbon disulphide to the extent of 0-14 per cent., whilst vapour density determinations by Dumas method give results corresponding with 2 per cent, association.3... 

Heated with baryta water in an atmosphere of nitrogen, carbon disulphide yields barium hydrosulphide, which is subsequently converted into sulphate by contact with the air (see p. 264) 5... 

Arsenic exhibits allotropy, which is characteristic of non-metals the usual, more stable, metallic form resembles the typical metals in appearance and in being a fairly good conductor of electricity. Under atmospheric pressure it begins to volatilise at about 450° C. and passes into a vapour containing complex molecules, As4, which at higher temperatures dissociate to As2 this complexity is not unusual in non-metals. The yellow allotrope, which is stable at low temperatures, resembles white phosphorus in being soluble in carbon disulphide—a property which emphasises the non-metallic character of this variety. The reactivity of the allotropes, as in the case of phosphorus, differs considerably. 

The grey form may be obtained from the yellow in carbon disulphide solution by treating with alcohol, or by cooling with carbon dioxide and ether or with liquid air. It is stable towards atmospheric oxygen, and is oxidised by nitric acid more slowly than the brown and metallic modifications. 

Arsenic Pentiodide ( ), Asls.—When a mixture of arsenic and iodine in the requisite proportions is heated in an atmosphere of carbon dioxide in a sealed tube at 150° C., a brown crystalline product is obtained.3 The crystals, which melt at 70° C. and have density 3-93, are soluble in water, carbon disulphide, alcohol, ether and chloroform. The solution in carbon disulphide yields, when allowed to crystallise, a mixture of arsenic triiodide and iodine. The latter is readily lost from the pentiodide, and heating at 100° C. in nitrogen in a sealed tube brings about the decomposition. Like the triiodide, the pentiodide dissolves boron tribromide.4... 

Notes. (1) Pyridine was stored over potassium hydroxide and distilled immediately before use. The tris(cyclohexyl)phosphine-carbon disulphide complex is prepared by the method of K. Issleib and A. Brack.9 This involves the addition of carbon disulphide to an ethereal solution of tricyclohexylphosphine, the precipitate is washed with light petroleum (b.p. 50-60 °C), and recrystallised under a nitrogen atmosphere from either methanol, ethanol or dioxane the complex has m.p. 118 °C. 

Subsulphides.—Several supposedly subsulphides of iron have been described from time to time, namely FeJS,6 Fe2S,6 and Fe4S3. The last-named is produced when iron is heated m an atmosphere of carbon disulphide vapour, at 1300° to 1400° C., and allowed to cool in the disulphide vapour.7 It is a crystalline body of density 6 96, and soluble in dilute mineral acids. evolving hydrogen sulphide and hydrogen. It does not alter when exposed to air, and is oxidised only with difficulty. 

The iodine which separates may be recognised either by the reddish-violet colouration which it imparts to chloroform or to carbon disulphide, or by the blue colouration which is produced with starch solution. This latter reaction can be adapted in practice by employing starch-iodide paper, which when exposed even for a short period to an atmosphere containing chlorine assumes a blue colour more or less intense according to the concentration of chlorine present. According to the experiments of Smolczyk a content of 14 mgm. chlorine per cu. m. of air produces a change in the colour of starch-iodide paper within 3-5 seconds. 

Sandalls, F. J. and Penkett, S. A., 1977 Measurements of carbonyl sulphide and carbon disulphide in the atmosphere. Atmospheric Environment 11, 197-199. 

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