Sulphide reactivity

Saturated Aliphatic Sulphides Aryl Sulphides.— Reactivity of aryl alkyl sulphides towards Br2 in AcOH decreases in the order Pr, Et, Me, though the opposite order applies to the oxygen analogues. 

Ozone is very much more reactive than oxygen and is a powerful oxidising agent especially in acid solution (the redox potential varies with conditions but can be as high as + 2.0 V). Some examples are 1. the conversion of black lead(ll) sulphide to white lead(II) sulphate (an example of oxidation by addition of oxygen) ... 

Sulphur is less reactive than oxygen but still quite a reactive element and when heated it combines directly with the non-metallic elements, oxygen, hydrogen, the halogens (except iodine), carbon and phosphorus, and also with many metals to give sulphides. Selenium and tellurium are less reactive than sulphur but when heated combine directly with many metals and non-metals. 

Spontaneous Pyrophoric deposit Deposits Water reactive Sulphides Oily rags, oil impregnation of lagging Heat transfer salt ... 

Reactivities of carbon disulphide, carbon dioxide and carbonyl sulphide towards some transition metal systems. J. A. Ibers, Chem. Soc. Rev., 1982,11, 57-73 (78),... 

The well-known fact that enantiomers exhibit different reactivity towards chiral reagents has been used to obtain optically active sulphoxides in a process which is called kinetic resolution. Kinetic resolution of sulphoxides usually involves either oxidation to the corresponding sulphones or reduction to sulphides by means of proper chiral oxidizing or reducing agents. 

Pyrophoric deposit Deposits Water reactive Sulphides... 

Although this mechanism could explain the inertness of di-t-butyl sulphide towards oxidation due to the absence of a-hydrogen atoms, it was later ruled out by Tezuka and coworkers They found that diphenyl sulphoxide was also formed when diphenyl sulphide was photolyzed in the presence of oxygen in methylene chloride or in benzene as a solvent. This implies that a-hydrogen is not necessary for the formation of the sulphoxide. It was proposed that a possible reactive intermediate arising from the excited complex 64 would be either a singlet oxygen, a pair of superoxide anion radical and the cation radical of sulphide 68 or zwitterionic and/or biradical species such as 69 or 70 (equation 35). 

Copper (II) sulphide is like any other sulphide, ie very reactive vis- -vis oxidants. Therefore detonations occur during mixtures between this compound and magnesium, zinc and cadmium chlorates. 

The chemistry of a-haloketones, a-haloaldehydes and a-haloimines Nitrones, nitronates and nitroxides Crown ethers and analogs Cyclopropane derived reactive intermediates Synthesis of carboxylic acids, esters and their derivatives The silicon-heteroatom bond Syntheses of lactones and lactams The syntheses of sulphones, sulphoxides and cyclic sulphides... 

Cruz R., Bertrand, V., Monroy, M., GonzAlez, I. 2001. Effect of sulphide impurities on the reactivity of pyrite and pyritic concentrates a multi-tool approach. Applied Geochemistry, 16, 803-819. 

This technique uses a nitrogen atmosphere in grinding and flotation to retard oxidation of reactive sulphides, and has been successfully applied on carbonaceous ores from Nevada (USA). The effectiveness of the method depends on (a) the amount of carbonaceous gangue present in the ore, and (b) the amount and type of clay. Ores that are high in carbon or contain high clay content (or both) are not amenable for nitrogen atmosphere flotation. 

Esters which are unstable and/or too reactive, such as those of CF3S03H, require a negative modifier (donor), e.g., a dialkyl sulphide, to give living systems such modifiers form a D-A complex with an acceptor centre, e.g., the acidic protons, at the growing end. 

At the same time a small amount of hydrogen sulphide is also eliminated. The main product of this reaction, carbodiphenylimide (di-phenylcyanamide), an extremely reactive substance, combines with the aniline present in the solution to form triphenylguanidine in the same way as, from cyanamide itself and ammonia, the unsubstituted guanidine is formed. 

Sandmeyer s valuable isatin synthesis involves the removal of sulphur from diphenylthiourea (I) (p. 169) with basic lead carbonate. Hydrogen cyanide is combined with the reactive diphenylcarbodiimide (II) so obtained, and the nitrile (III) produced is converted by means of hydrogen sulphide into tbe thioamide (IV). Concentrated sulphuric acid brings about ring closure and the product is the a-anil of isatin (V). Then, by hydrolysis with dilute sulphuric acid, aniline is removed ... 

The A3-phospholen sulphides (44), bearing reactive functional groups, may be reduced to the phosphine using nickelocene in the presence of allyl iodide.37 The intermediate nickel complex is decomposed with cyanide to free the functionalized A3-phospholen (45). 

A further illustration has appeared28 of the reactivity of simple a-keto-alkyldi-phenylphosphine oxides (31) towards addition reactions, as outlined in Scheme 5. In the same paper, alkylation of chloro(di-t-butyl)phosphine (32) by alkyl benzoates is described 28 see Chapter 3 for details. A similar acylation reaction of tetramethyl-diphosphine disulphide (33) has been described, although the acetylphosphine sulphide (34) was not isolated.29... 

The deoxygenation of some penicillin and cephalosporin sulphoxides has been accomplished by the use of phosphorus pentasulphide.53 The reactive species responsible for deoxygenation was not identified. A particularly mild method for reducing sulphoxides to sulphides involves the reaction of the sulphoxide with 2-chloro-l,3,2-benzodioxaphosphole at room temperature.536 Yields in excess of 80% were reported. 

As one might expect, the mesomeric effect of an alkoxy group enhances the activity of the C=C to attack by the carbene, but it has been noted that, where there is competition between an alkoxyvinyl group and an inactivated alkene group within the same molecule, an alkyl or aryl group stabilizes the transition state better than does the vinyloxy group (Scheme 7.10) [56]. It is noteworthy that vinyl sulphides are five times more reactive than are the enol ethers [62]. 

Feng Qiming, 1989. Pulp electrochemistry of flotation of sulphide minerals theory and technology (Ph.D. thesis). Central South University of Technology Feng Qiming, Chen Jin, Xu Shi, 1991. Relationship between thermodynamics, property of reactive products on sulphide and collectorless flotation separation of sulphide minerals. J. CSIMM (suppl.), 22(3) 28 - 35... 

In natural environments, abiotic reduction may also be effected by a range of natural reductants including sulphide and methane. In the sulphide producing sediments in the Long Island Sound and the Mississippi Delta, for example, Fe oxides have been transformed to Fe sulphides (FeS and FeS2) (Canfield Berner, 1987 Boesen Postma, 1988). As a result, when there was a sufficient supply of reactive Fe oxides in the sediments, hardly any dissolved sulphide was found in the pore water. The reduci-... 

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