Desulphurization

H. A. Corver and W. Gmohling, "Hot Metal Desulphurization—North American Experience with CaD," Iron SteelEng (May 1980). 

W. G. Wilson and A. McLean, "Desulphurization of Iron and Steel and Sulfide Shape Control," The Iron and Steel Society of AIME, Warrendale, Pa.,... 

As there now exists a large body of laboratory studies on each of the variable systems, for example the effect of die lime/silica ratio in the slag on the desulphurization of liquid iron, the most appropriate phase compositions can be foreseen to some extent from these laboratory studies when attempting to optimize the complex indusuial process. The factorial uials are not therefore a shot in the dark , but should be designed to take into account die laboratory information. Any qualitative difference between die results of a factorial uial, and the expectations predicted from physico-chemical analysis might suggest the presence of a variable which is important, but which was not included in the nials. 

Merrick, 1989. David Merrick and Jan Vernon, "Review of Flue Gas Desulphurization Systems," Chemistry and Industry, February 6, 1989. 

The orange thiocarbonyl is air stable (IR i/(C=S) 1332 cm-1) its synthesis proceeds via an isolable C2S5 complex that is desulphurized by refluxing with PPh3 [144] ... 

The reaction of the phenylsulphinyl allylic lithium a-carbanion 342 with oxiranes was found by Guittet and Julia to give, after rearrangement and desulphurization, dihydroxy-dienes 343427 (equation 197). Demoute and coworkers have described the alkylation reaction of a very sophisticated 2-alkenyl sulphoxide 344 as a part of the total synthesis of a juvenile hormone 345428 (equation 198). Since the allylic sulphoxide carbanion has an ambident character, the alkylation may occur sometimes also at the y-position. This direction of alkylation is observed in the case of acyclic allylic sulphoxide anions 346, and results in the formation of the corresponding allylic sulphoxide 347 and vinylic sulphoxide 348423 (equation 199). 

Reaction of benzylideneaniline with optically active methyl p-tolyl sulphoxide 449 in the presence of lithium diethylamide produces the corresponding jS-anilinosulphoxide 450 with 100% asymmetric induction. Its reductive desulphurization with Raney nickel leads to the enantiomerically pure amine 451524 (equation 270). When the same optically active... 

The first study into the use of 6% sodium amalgam in refluxing ethanol for the reductive desulphurization of sulphones was reported116 in 1952. Methyl phenyl sulphone gave an... 

The use of Raney nickel for desulphurization reactions has been well known for a considerable time144. Some work has been carried out on sulphones, the most notable... 

Various thiirans have been desulphurated to the corresponding ethylenes with triphenylphosphines. For other desulphuration and related reactions see Chapter 10, Section 2. 

E. Miscellaneous Reactions.—Desulphurization of S-labelled benzyl trisulphide (119) with triphenylphosphine leads to predominant removal of the central sulphur atom, while reaction with tris(diethylamino)-... 

Isopropyl (/ )-( —)-methylphosphinate (134) has been prepared" in > 90% optical purity by Raney nickel desulphurization of optically pure O-isopropyl (5)-(-f-)-methyIphosphonothioate (135). The phosphonate (134) is rapidly racemized by base, but not by acid, unlike secondary phosphine oxides"" [although whether these have been prepared optically active now seems doubtful (see Chapter 4)]. The phosphinate (134) can be reconverted into 89% optically pure (5)-( + )-(135) by addition of sulphur in dioxan. As shown in the Scheme, a series of interconversions has been used to establish the configurations. 

Silver ions will oxidatively desulphurize nucleoside and other phos-phorothioates to generate a phosphorylating agent. This reaction has been utilized for the preparation of nucleotide coenzymes and has the advantage that it can be carried out on a large scale without the formation of contaminating symmetrical pyrophosphates. 

With phosphorus trichloride, a rather complex reaction results partly in the formation of [PhaP N uPPha PPhCl]+ Cl. The reactivity of the phosphorus(iii) atom is also demonstrated by its ability to desulphurize thiophosphoryl chloride, and its ready reactions with Group VI elements, diborane, and carbon disulphide ... 

Dialkyl thiosulphonates (37) are desulphurized by tris(diethylamino)phos-phine to give sulphoxides. In some cases sulphinate esters are formed as minor products. Diaryl thiosulphonates gave 1 1-adducts of the type (38). Desulphurization of sulphenimides (39) by tris(dimethylaniino)phos-... 

Desulphurization of the disulphide (44) has been shown to result in epimerization at the asymmetric carbon atoms. Synthetic applications of... 

Gilbert SC, 1 Morton, S Buchanan, C Oldfield, A McRoberts (1998) Isolation of a unique benzothiophene-desulphurizing bacterium, Gordona sp. strain 213E (NCIMB 40816), and characterization of the desulphurization pathway. Microbiology (UK) 144 2545-2553. 

Oldfield C, O Pogrebinsky, J Simmonds, ES Olson, CE Kulpa (1997) Elucidation of the metabolic pathway for dibenzothiophene desulphurization by Rhodococcus sp. strain IGTS8 (ATCC 53968). Microbiology (UK) 143 2961-2973. 

There have apparently been no recent developments in reagents for desulphurizing sulphoxides that use pentavalent phosphorus compounds. Reagents that were reviewed in 1984 include phosphorus pentasulphide, thiophosphoryl bromide, Lawesson s reagent (1), and phosphorus pentachloride in the presence of a trap for CD ions. The traps used included an enamine or an N, JV-dialkylaniline. Presumably, the net effect of this reaction is to generate phosphorus trichloride in situ. The three thiophosphorus reagents obviously function because the P=S bond is some 150 kJ moD weaker than the P=0 bond . 

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