Ethyl methyl disulphide

Carbon-sulphur bond homolysis has been shown to be, in addition to sulphur-sulphur bond homolysis, a primary process in the photolysis of disulphides in solution. Sulphur-sulphur bond homolysis is, however, responsible for the establishment of an equilibrium between various alkyl disulphides on irradiation." Other liquid-phase studies of the photodecomposition of acyclic alkyl disulphides have been reported," -and the quantum yield for the formation of methyl ethyl disulphide from methyl disulphide and ethyl disulphide has been determined. ... 

Water with aniline, benzene, benzyl alcohol, carbon disulphide, carbon tetrachloride, chloroform, cyclohexane, cyclohexanol, cyclohexanone, ether (particularly if acidified), ethyl acetate, isoamyl alcohol, methyl ethyl ketone, nitromethane, tributyl phosphate or toluene. 

The solvents more generally used are oil of turpentine, pinewood oil, methyl, ethyl or amyl alcohol, amyl acetate, acetone, ether, carbon disulphide, carbon tetrachloride, chloro-derivatives of ethane and ethylene, chlorohydrins, light mineral oils, light oils from tar, from resin or from shale, and camphor oil. 

In fig. 21.4 all the activity coefficients are less than unity, and the total pressure p is less than the perfect pressure represented by the line PiP2- Ir this case we describe the deviations from ideality as negative. An example of this behaviour is to be found in chloroform -h ethyl ether solutions. Alternatively the deviations from ideality may be positive as in methylal + carbon disulphide solutions (fig. 21.5). 

BDTPTS bis(di-ethyl thiophosphoryl) trisulphide CBS N-cyclo hexyl benzthiazyl sulphenamide MBTS mercaptobenzothiazole disulphide NOBS N-oxy di-ethylene benzthiazyl sulphenamide TMTD tetra-methyl thiuram disulphide DBG N, N diphenyl guanidine ... 

The inflammable solvents most frequently used for reaction media, extraction or recrystallisation are diethyl ether, petroleum ether (b.p. 40-60° and higher ranges), carbon disulphide, acetone, methyl and ethyl alcohols, di-Mo-propyl ether, benzene, and toluene. Special precautions must be taken in handling these (and other equivalent) solvents if the danger of Are is to be more or less completely eliminated. It is advisable to have, if possible, a special bench in the laboratory devoted entirely to the recovery or distillation of these solvents no flames are permitted on this bench. 

Ammonium nitrate and other ammonium salts Any oxidizable substance, such as ethanol, methanol, glacial acetic acid, acetic anhydride, benzaldehyde, carbon disulphide, glycerol, ethylene glycol, ethyl acetate, methyl acetate or furfural Chlorates, perchlorates, permanganates... 

Care must be taken in the choice of organic solvent. Chloroform should never be used under the basic conditions due to the risk of the formation of isocyanides (see Chapter 7) and the use of carbon disulphide can lead to formation of dithiocarba-mates, e.g. dimethyl A -(ethoxycarbonylmethyl)iminodithiocarbonate is formed (35-39%), as the major product in high purity, in the liquiddiquid two-phase methyl-ation of ethyl glycinate in carbon disulphide [15]. The product is useful as an intermediate in the synthesis of thiazoles [15] and dihydrooxazoles [16]. 

Similarly with the raising of the b.p. in violet or reddish-violet soln. of iodine in benzophenone, carbon disulphide, ethyl chloride, chloroform, carbon tetrachloride, ethylene chloride or benzene or in brown soln. of ethyl alcohol, methyl alcohol, thymol, ethyl ether, methylal, or acetone. The values for the last three solvents were rather low, presumably because of the chemical action of solute on solvent. High values with benzene are attributed to the formation of a solid soln. of solvent and solid. Confirmatory results were found by J. Hertz with naphthalene, and by E. Beckmann and P. Wantig with pyridine. The results by I. von Ostromisslensky (o-nitrotoluene), by G. Kriiss and E. Thiele (glacial acetic acid), and by H. Gautier and G. Charpy indicate polymerization, but they are not considered to be reliable. 

Di-m-tolyl tellurium dichloride, (CH3.C6H4)2TeCl2,3 is formed when di-m-tolyl telluride in ether solution is chlorinated. The product appears as needles, sintering at 128° C. and melting at 131° to 132° C., readily soluble at the ordinary temperature in benzene, toluene, xylene, carbon disulphide, chloroform or carbon tetrachloride, less soluble in methyl or ethyl alcohol, insoluble in petroleum. When the dichloride is boiled with water a white powder separates on cooling this melts at 87° C. to a viscous oil which gradually becomes watery. Analysis shows this product to be a basic salt and not the anhydride. 

Di-o-phenetyl tellurium di-iodide, (C2H5O.C6H4)2TeI2, crystallises as four-sided columns or rhombic plates, sintering at 212° C., melting at 214° to 215° C., dissolving readily in cold chloroform or carbon disulphide, also in benzene, toluene or xylene at the ordinary temperature, very slightly soluble in methyl or ethyl alcohol. 

Di-o-phenetyl tellurium oxide, (C2H5O.C6H4)2TeO.—The dibromide in a finely divided state is boiled with concentrated ammonium hydroxide until the colour changes from yellow to white. The product crystallises from toluene as short needles, sintering at 202° C. and melting at 205° to 206° C. The oxide dissolves in chloroform and methyl or ethyl alcohol in the cold, also in warm benzene, toluene, xylene or carbon disulphide it is very sparingly soluble in carbon tetrachloride. 

Di-m-xylyl tellurium di-iodide, [(CH3)2C6H3]2TeI2, forms ruby-red columns, sintering at 179° C. and melting at 181° to 182° C. It dissolves in benzene, toluene, xylene, chloroform or carbon disulphide, is sparingly soluble in ether or ethyl alcohol, and insoluble in methyl alcohol or petroleum ether. 

Mercaptans. — Bunge3 electrolyzed the alkali salts of ethyl and methyl mercaptans and observed the formation of disulphides at the positive pole. In the case of the sulpho-compounds, however, the free adds were generated. 

Fig. 18.VmJ. Vapour Pressure Curves. Abscissae in degrees C., ordinates vapour pressures in mm. Hg. The substances corresponding with the numbers attached to the curves are 1 ammonia, 2 chlorine, 3 methyl ether, 4 cyanogen, 5 sulphur dioxide, 6 ethyl chloride, 7 isopentane, 8 ethyl ether, 9 pentane, 10 carbon disulphide, 11 ethyl formate,...

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