Sodium sulfide synthesis

Researchers at Phillips Petroleum Company developed a commercially viable process for the synthesis of PPS involving the polymerization of /)-dich1orohenzene and a sodium sulfide source in a polar organic compound at elevated temperature and pressure. This Phillips process was patented in 1967 (18). Between 1967 and 1973, Phillips built and operated a pilot plant, estabhshed market demand, and constmcted a hiU-scale commercial plant. In 1973, the world s first PPS plant came on-stream in Phillips faciUty in Borger, Texas. 

The synthesis of thiophene from diacetylene was first performed by Schulte (62CB1943), who used sodium sulfide in aqueous alcohol (pH 8-10), the yield being no more than 20%. 

Because sodium sulfide is a strong nucleophile, other non nucleophilic reagents such as Ca/Hg 144 or Bu3SnH145 are more suitable than Na2S in the synthesis of functionalized olefins (see Eq. 7.105). NaTeH is also effective to induce the elimination reaction presented in Eqs. 7.103 and 7.104.146... 

In contrast, synthesis of 3,4-diphosphorylthiophenes requires more elaboration because of low reactivity of 3,4-positions of thiophene and unavailability of 3,4-dihalo or dimetallated thiophenes. Minami et al. synthesized 3,4-diphosphoryl thiophenes 16 as shown in Scheme 24 [46], Bis(phosphoryl)butadiene 17 was synthesized from 2-butyne-l,4-diol. Double addition of sodium sulfide to 17 gave tetrahydrothiophene 18. Oxidation of 18 to the corresponding sulfoxide 19 followed by dehydration gave dihydrothiophene 20. Final oxidation of 20 afforded 3,4-diphosphorylthiophene 16. 3,4-Diphosphorylthiophene derivative 21 was also synthesized by Pd catalyzed phosphorylation of 2,5-disubstituted-3,4-dihalothiophene and converted to diphosphine ligand for Rh catalysts for asymmetric hydrogenation (Scheme 25) [47],... 

The synthesis of polysulfide elastomers involves the use of a small amount of trichloroalkane in addition to dichloroalkane and sodium sulfide in order to form a branched polymer. The prepolymer is treated with a mixture of sodium hydrosulfide and sodium sulfite followed by acidification to convert all end-groups to thiol groups. Further polymerization and crosslinking is achieved by oxidative coupling of the thiol end-groups by treatment with lead dioxide, p-quinone dioxime, or other oxidizing agent... 

The by-product, representing a relatively reduced form of sulfur, is a reasonable model for the sulfur impurities in the synthesis gas obtained from sulfur-rich coal. This sodium sulfide test of sulfur resistance of water gas shift catalyst systems generated in basic solutions is a very severe test since the quantities of sulfur involved are much larger than those likely to be found in synthesis gas made from any sulfur-rich coals. 

The first stage of the synthesis involves the interaction of a nitro compound with sodium sulfide. When used alone, sodium sulfide is only slightly effective The reactions proceed slowly and the yields of mercaptanes are small. If elemental sulfur is added, the conversion accelerates markedly and the yield increases to 75-80%. The promoting effect of elemental sulfur can be easily explained by the radical-chain mechanism. The reaction starts with one-electron transfer from the nucleophile to the nitro compound further conversions resemble other chain ion-radical substitutions. 

Fahey, D. R. and J. F. Geibel, Poly(/>-phenylene sulfide) (Synthesis by p-Dichlorobcnzcnc and Sodium Sulfide), pp. 6506-6515 in Polymeric Materials Encyclopedia, J. C. Salamone, ed., CRC Press, Boca Raton, FL, 1996. 

The technically most important polysulfide is poly thiophenylene or poly(p-phe-nylene sulfide), PPS. It is obtained by reacting sodium sulfide and p-dichlo-robenzene in a polar solvent, for example, l-methyl-2-pyrrolidone at about 280 °C under pressure. The mechanism of the reaction is very complex and cannot be described by a simple aromatic substitution. This synthesis requires special autoclaves and is therefore not suitable for a laboratory course (for an experimental procedure see Table 2.3). 

The most important applications of hydrogen sulfide involve the production of sodium sulfide and other inorganic sulfides. Hydrogen sulfide obtained as a by-product often is converted into sulfuric acid. It also is used in organic synthesis to make thiols or mercaptans. Other applications are in metallurgy for extracting nickel, copper, and cobalt as sulfides from their minerals and in classical qualitative analytical methods for precipitation of many metals (see Reactions). It also is used in producing heavy water for nuclear reactors. 

Two general methods have been described for the synthesis of this new class of meso-ionic compounds (196). The most convenient method is by the treatment of 4-bromo-l,2,3-triazolium salts (197, X = Br) with sodium sulfide in dimethylformamide. Alternatively, N-methylation of the isomeric 4- or 5-alkylmercapto-1,2,3-triazoles 198 or 199 with methyl tosylate gave intermediate triazolium salts (197, X = SR, Y = Tos), which yielded meso-ionic l,2,3-triazole-4-thiones (196) by 5-dealkylation by heating with piperidine. 

Dihydrothieno[3,4-Z ]thiophene (131) was prepared by two methods. In the first (Scheme 8), chloromethylation of methyl thiophene-2-carboxylate (132) forms methyl 2,3-bischloromethyl-thiophene-5-carboxylate (133) (85%) cyclization of 133 with sodium sulfide in methanol yields (66%) methyl 4,6-dihydrothieno[3,4-i]-thiophene-2-carboxylate (134). Peroxide oxidation of 134 gives 2-methoxycarbonyl-4,6-dihydrothieno[3,4-h]thiophene 5,5-dioxide (135) and hydrolysis of 134 followed by metaperiodate oxidation furnishes the sulfoxide (91). Thienothiophene (131) was produced by hydrolysis and decarboxylation of 134. As indicated above, the sulfoxide (91) was used for the synthesis of thieno[3,4-6]thiophene (3). 

Dioxins, 1,4-oxathiins, and 1,4-dithiins have often been prepared by elimination reactions from saturated analogs as described in CHEC-II(1996) <1996CHEC-II(6)447>. Since then, a synthesis of tetramethyl l,4-dithiin-2,3,5,6-tetracarboxylate 241 has been reported in low yield (12%) by thermal decomposition of the 1,4,2,5-dithiadiazine system 240 in refluxing o-dichlorobenzene in the presence of DMAD <1997J(P1)1157>. Recently, 2,6-divinyl-l,4-dithiin 68 has been isolated from the reaction of l,4-bis(4-bromobut-2-ynyloxy)benzene with an excess of alumina-supported sodium sulfide. The formation of 68 has been presumed to take place via cyclic sulfide 242 <2003S849>. 

The influence of the addition of cetyl trimethyl ammonium chloride, CTAC, to the reverse micellar solution affects the droplet size and micellar interactions, as demonstrated by the DQLS experiment (64). Addition of CTAC to micellar system at a given water content leaves the droplet size unchanged, whereas a decrease in the intermicellar attraction has been observed. This decrease is more important for high CTAC concentrations. This has been interpreted to steric repulsion induced by the long hydrocarbon tail of CTAC (C ft). Thus, the addition of this compound to CdS synthesis could modify the nucleation and/or growth process. The experiments were performed by solulization of CTAC in the micellar solution containing either sodium sulfide or Cd(AOT)2. 

Sodium toluene dispersion of, 55, 65 Sodium p-toluenesulfinate, 57, 103 Spiro[4 n] alkenones, 58, 62 Spiro[cyclopentane-l,l -indene] 55, 94 Squalene, 56, 116 Squalene, 2,3-epoxy, 56, 116 Stannic chloride, 56, 97 Steroids synthesis, 58, 85 E Stilbene, 55, 115,58, 73 z-Stilbene, 58, 133 Styrene, 56, 35,58, 43 Styrene glycol, 55, 116 Styrene glycol dimesylate, 55, 116 Succinic acid, 58, 85 Succinic anhydride, 58, 85 Sucunimide, 56, 50, 58, 126 Succimmide, Vbromo, 55, 28, 56, 49 SULFIDE CONTRACTION, 55, 127 Sulfide, dimethyl-, 56, 37 SULFIDE SYNTHESIS, 58, 143,58, 138 SULFIDE SYNTHESIS ALKYL ARYL SULFIDES, 58, 143 SULFIDE SYNTHFSIS DIALKYL SULFIDES, 58, 143 SULFIDE SYNTHESIS UNSYMMETRI-CAL DIALKYL DISULFIDES, 58, 147 SULFONYL CYANIDES, 57, 88 Sulfur tetrafluoride, 57, 51... 

An efficient synthesis of thietanes (29) via reaction of 1,3-dihalo alkanes (28) with sodium sulfide was recently reported by Lancaster and Smith.S7... 

Nucleophilic addition at the 2-position of pyrylium salts (223) occurs readily under mild conditions and when ammonia or primary amines are used the subsequent ring-opening/ring-closure sequences give pyridines (224) and pyridinium salts (222), respectively (Section 3.2.1.6.4.iii). The process is most useful for the synthesis of 2,4,6-trisubstituted pyridine derivatives. Thiinium salts (226) are conveniently prepared from pyrylium salts (225) by treatment with sodium sulfide (Section 3.2.1.6.5), Thiinium salts (226) react with ammonia and amines similarly to their pyrylium analogues. 

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