Sulphur production

Dispersion of soluble rhombic sulphur does not usually create problems in most polymers, but addition of the insoluble form can create problems of incorporation into the rubber compound due to insolubility in the rubber. The insoluble sulphur particles tend to agglomerate into small lumps, which cannot then be dispersed effectively. Various treated insoluble sulphur products are available which aid incorporation. 

Sodium sulphide NaOCl + NaiS => NaCl + sulphur products (26.5)... 

Along with processing changes to achieve higher synthetic crude yields, the employment of future technology will result in greater quantities of sulphur production. 

Formation of naphthalene from phthalic anhydride and thiophene implies the extrusion of sulphur. Products arising from the reaction of this sulphur, possibly monatomic and hence highly reactive (Sidhu et al., 1966) with thiophene might be expected. Indeed, the mass spectrum revealed a product of molecular weight 116 and an isotopic distribution establishing the elemental composition as C4H4S2, doubtless thio-phenethiol. The relative amounts of the products were ... 

Sulphoselenides.—When the selenides of phosphorus are melted with sulphur, products are obtained which have the composition P4SSe2 (m.pt. 225° to 230° C.) and P4S2Se (m.pt. 190° to 200° C.).s ... 

Tonzetich, J. McBride, B.C. Characterization of volatile sulphur production by pathogenic and non-pathogenic strains of oral bacteroides. Arch. Oral Biol. 1981, 26, 963-969. 

V. SULPHURIC ACID AND SULPHUR PRODUCTS. By Gkoi-trky Martin, Th D., D.Sc. and J. Louis Foucar, B.Sc. 

Reaction (8.5)(iv) results in the formation of the less reactive disulphide from the more reactive thiyl, RS-, radical and thiolate anion, RSCl ". This explains the smaller amount of sulphur product formation in boundary lubrication with dibenzyl disulphide and chlorinated paraffin [91]. Assuming this to be the case, electron transfer between an initially formed disulphide radical anion and a chlorinated paraffin appears to be an additional explanation for the increased reactivity of chlorinated paraffin in the presence of disulphide. 

Pigments and Chemicals titanium dioxide industrial chemicals (aniline, HCN, amides and amines, sodium, lithium and sulphur products) performance chemicals (fabric protectors, lubricants, oxidising agents) ... 

The stoicheiometry and kinetics of reaction of aqueous ammonia solutions of copper(ii) ions with thiosulphate ion in the presence of oxygen have been examined. The amount of oxygen consumed and the relative amounts of the final sulphur products, namely trithionate and sulphate ions, are dependent on the initial 8203 concentration and pH. The most active species for SjOe" formation is a tetra-amminecopper(ii) complex having one axial 8303 and one axial O2 ligand. A complex having both axial and equatorial 8203 ligands as well as an axial O2 was suggested as the reactive intermediate for sulphate formation. 

Analyser systems are expensive and should therefore be adequately protected from their environment and the process streams that they control. Every analyser is liable to malfunction upon contact with rain, snow, Ice, wind, sand, dust and so forth. After some time, alternate hot-cold or humid-dry periods cause expansions and compressions that results In erosion and corrosion of the analyser. On the other hand, industrial environments are particularly severe as the rain and atmospheric humidity react with traces of hydrocarbons, sulphurized products and nitrogen oxides to form acids which accelerate corrosion. All these reasons recommend protecting the analyser to an extent depending on the potential hazards of the area where the analyser is... 

The numerous amino-adds which are met in the products of advanced tryptic hydrol)rsis are of quite different constitution. Some possess only an add function and an amine function others are di-adds and mono-amines, or mono-adds and di-amines. Some have an alcohol function others are sulphur products. Finally, these compounds are sometimes of straight chain, sometimes of dosed chain constitution. Yet, we may say that all answer to the general formula, R — CHCNHj) — COjH, which shows that there is at least a grouping NHj fixed on the C adjacent to carboxyl, R bdng an acyl, an aromatic or heterocyclic radical. The following is a list of these compounds ... 

SAFFA (matches, sulphur products) [public company] 100... 

Zinc, Cadmium, Indium, Germanium Sulphur Products... 

Sulphur recovery consists of a hydrocyclone and two parallel flotation circuits. Normally, over 95% of the elemental sulphur is recovered in this circuit. Work is ongoing to improve the recovery of the finer sulphur size fraction. The sulphur concmtrate is dewatered on a belt filter, melted and passed through a molten sulphur filter to remove unreacted minerals and ash to produce a marketable sulphur product. 

With lower oxygen availability, lower temperature and higher acid concentration, oxidation of pyrite may result in some elemental sulphur production. 

Atypically, there are a few materials which occur in an elemental form. Perhaps the most notable example is sulphur, which occurs in underground deposits in areas such as Louisiana, Southern Italy and Poland. It can be brought to the surface using the Frasch process in which it is first melted by superheated steam and then forced to the surface by compressed air. This produces sulphur of high purity. Substantial quantities of sulphur are also removed and recovered from natural gas and crude oil (petroleum). This amounted to 24 million tonnes out of a total world sulphur production of 37 million tonnes in 1991, and clearly demonstrates the vast scale on which the oil and petrochemical industries operate since crude oil normally contains between 0.1 and 2.5% of sulphur, depending on its source. Desulphurization of flue gases from some U.K. power stations will be another source of sulphur in the future. Over 80% of all sulphur is converted into sulphuric acid, and approximately half of this is then used in fertilizer manufacture. 

Anonymous. 1980. Elemental Sulphur Production Recovery From Low-Grade Pyrites and Phosphogypsum, Sulphur, No. 147(March-ApriI) 36-38. 

S—S— Oxidations. As shown in the above scheme, the oxidation of disulphides can lead to a variety of compound types. In the earlier ones, the —S—S— bond is preserved, whereas further oxidation leads to the mono-sulphur products, sulphinic and sulphonic acids. For asymmetric disulphides, the point of first oxidation to monosulphoxide (thiosulphinate) is adjacent to the more electron-donating substituent. This is usually carried out by peracid systems at or below ambient tern-... 

Increasing the CO2 slippage in the Amine absorbers has reduced the CO2 content of Acid Gas considerably and stopped the anti-environmental Acid Gas flaring from AGRU. This achievement has saved and protected the environment from the impact of flaring around 300 mmscf of Acid Gas and therefore a loss of around 2610 tons of liquid sulphur product estimated to be 1.72 MM QR has been avoided. 

Phytoalexins are low molecular weight products which are produced in response to elicitors such as microbial, herbivorous or environmental stimuli (Poulev et al. 2003). Once plants detect a pathogen signal, a complex mixture of secondary metabolites is produced to control the invader. These molecules are synthesized de novo, and thus involve the activation of certain genes and enzymes required for their synthesis (Kuc 1995). Phytoalexins are chemically diverse and may include many chemical classes such as simple phenylpropanoid derivatives, alkaloids, gly-costeroids, flavonoids, isoflavonoids, various sulphur products, terpenes and polyketides (Hammerschmidt 1999). There is no boundary between phytoalexins and phytoanticipins, and in one plant species a certain chemical can function as a phytoalexin, whereas it has the function of a phytoanticipin in another species (Junghanns et al. 1998). It is important to point out that the distinction between phytoanticipins and phytoalexins is not based on their chenucal structure but rather on how they are produced. Thus, the same chemical may serve as both phytoalexin and phytoanticipin, even in the same plant (VanEtten et al. 1994). 

This is analogous to the reaction reported by Hayasi and Nozaki. Dimethylsulphonium(p-methyl)phenacylide reacted with diphenylthiiren dioxide to afford mainly diphenylacetylene and a mixture of sulphurous products, mainly (77) and (78), which may have been formed by carbanion attack at the double bond, acyl transfer, ring opening, and then ring closure of an enolate ion. ... 

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