Dimethyl sulphide, decomposition

Zahradnikova et al. dimethyl sulphide (DMS) reacts much faster with peracids than with other types of peroxides [14]. Although there still is discussion about this method, from peroxide determination before and after treatment with DMS it was concluded that the fast decomposing peroxides are peracids [15], resulting from aldehydes which are formed via the decomposition of hydroperoxides. ... 

However, unlabelled dimethyl sulphide is obtained from the reaction of 2-phenylethyl-2//2-dimethylsulphonium ion with hydroxide in water . Elimination from tri(ethyl-l,l-//2)-sulphonium ion with triphenylmethylsodium in ether gives triphenylmethane, 75% of which contains deuterium, indicating that the predominant route for the decomposition is via an ylid mechanism. The analyses of the other products are also in agreement with this conclusion... 

The highest concentration of hydrogen sulphide in biogas is noted in the early stages of waste decomposition. The decrease in the concentration of H S is most likely caused by the precipitation of the sulphides in the reaction with heavy metals (such as Cu and Fe) or their oxides, which are present in the deposited material. Sulphides as water insoluble compounds remain in the mass of waste (Parker et al. 2002). The organic sulfur compounds in the greatest concentrations in landfill gas are dimethyl sulphide (DMS), carbon disulphide, methyl mercaptan, dimethyl disulphide (DMDS) at the concentrations of 0.007-180 mg m" 0.09-61.6 mg m" 0.084-17.94 mg m 0.0124-0.942 mg m" respectively (Kim et al. 2005, Shin et al. 2002). 

A modification to the alkene ozonolysis reaction employs dimethyl sulphide to reduce the ozonide to a keto-aldehyde. Decomposition of benzoyl poroxide is accelerated by aliphatic sulphides or disulphides, owing to nucleophilic attack by sulphur at oxygen. An extension of work described in 1%9 by the same authors showing the ability of sulphides and thiols to quench pffioto-excited benzophenone has been described. ... 

DMSO can be boiled under reflux for long periods largely unchanged (3.7% of volatile decomposition products after 72 h) but under air or O2 in a sealed tube, kept just below the boiling point (189 C) for 68 h, it is completely transformed into paraformaldehyde, dimethyl sulphide, and bis(methylthio)methane, water, and dimethyl disulphide." " Peroxides catalyse the decomposition, as does MeSOjH." " The formaldehyde formed in this way can be used for in situ methylene acetal formation with oxidation products of alcohols and diols." Reduction of DMSO with Br2+HBr gives MezS, MeSOsH, and paraformaldehyde, while diphenyl sulphoxide is unchanged." ... 

In the previous section, transition-metal-substituted polyoxometalates (TMSPs) supported on Si02 [61, 62] have been mentioned. TMSPs have been also tested when immobilized on Ti02- For instance, the H5PW10V2O40 supported on Ti02 was active in the photocatalytic decomposition of dimethyl sulphide (DMS) in gas-... 

The compound crystallises in pearly plates, M.pt. 143° C., insoluble in water, fairly soluble in alcohol, easily in methyl iodide and ether. It sublimes without decomposition and yields the oxide with alkalies or ammonium hydroxide, whilst ammonium sulphide jorecipitates the sulphide in faint yellowish flocks.Distillation with potassium cyanide, >otassium hydroxide, or metallic potassium gives mercury dimethyl. Its molecular w eight in methyl or ethyl sulphide is normal. 

Decomposition of this intermediate would lead to dimethyl sulphoxide and phenyl methyl sulphide (equation 43). Diphenyl disulphide should... 

The exploration of novel preparative routes commands much attention in isothiazole chemistry. Especially interesting are the reactions of 3-phenyl-l,2,4-oxathiazol-5-one with acetylenic esters which afford isothiazoles in high yield (72, 7). The reaction is envisaged as a 1,3-dipolar addition of benzonitrile 7V-sulphide, produced as a transient intermediate, to the dipolarophilic dimethyl acetylenedicarboxylate or propiolic ester. Isothiazoles are also produced by photoisomerization of thiazoles (72, 19). Nitrenes may be implicated in the thermal decomposition of 2-azidoaryl thioketones into benzoisothiazoles (72, 51). 

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