Mercaptan yields

Hydrogen Sulfide andMercaptans. Hydrogen sulfide and propylene oxide react to produce l-mercapto-2-propanol and bis(2-hydroxypropyl) sulfide (69,70). Reaction of the epoxide with mercaptans yields 1-aLkylthio- or l-arylthio-2-propanol when basic catalysis is used (71). Acid catalysts produce a mixture of primary and secondary hydroxy products, but ia low yield (72). Suitable catalysts iaclude sodium hydroxide, sodium salts of the mercaptan, tetraaLkylammonium hydroxide, acidic 2eohtes, and sodium salts of an alkoxylated alcohol or mercaptan (26,69,70,73,74). 

Sulfur monochloride and sulfur dichloride also react with mercaptans, yielding tetra- and trisulfides (eqs. 8 and 9) (11). 

Dehydrosulphidation of thiols and sulphides is directly analogous to dehydration of alcohols and ethers. Thiols (mercaptans) yield both alkenes and sulphides... 

If secondary decomposition of the mercaptan is neglected for the moment, the mechanism proposed above, and expression (I) derived therefrom, should apply, with the modification that the total CHsS yield should be equivalent to the previously measured mercaptan yield. The... 

That the mercaptan product arises exclusively from singlet sulfur atom reactions was proven in experiments with added CO2. The data in Table VI clearly demonstrate the suppressing effect of COj on the mercaptan yield, with a concomitant and equivalent rise in episulfide production. Further substantiation comes from mercury-photosensitization studies with COS in which it was found that the sulfur atoms produced by this means yield only episulfide, no mercaptans being formed with ethylene or with any of the other olefins studied. 

Some experiments have been carried out with ethylene-ethane mixtures as well. The data given in Table VII show the expected trend, in that with increasing ethane pressure, at a fixed ethylene concentration, the ethyl mercaptan yield increases at the expense of the yields of vinyl mercaptan and episulfide. However, while vinyl mercaptan formation seems to be completely suppressible with increasing ethane pressure, this is not the case with the episulfide. This seems clearly to be due to the fact that the two mercaptans form in competing reactions for S( Z)) atoms, while episulfide can form from ( P) atoms, arising by the collisionally induced S( Z>) - S( P) transition. 

The photolysis of methyl mercaptan yields H2, CH4, H2S and (0113)282 as major products. At 2537 A, (H2) > 0.9. At low conversions, H2 is the only non-condensable formed, and experiments with CH3SD confirmed that the primary process is probably... 

Both of these compounds yield sulphides or thio-ethers. Thio-phenol by the diazo reaction yields di-phenyl sulphide, CeHs—S—Cell5, di-phenyl thio-ether and benzyl mercaptan yields di-benzyl sulphide, CeHs—CH2—S—CH2—CeHs, di-benzyl thio-ether. These sulphides on oxidation yield sulphones (p. 526). 

With multifunctional thiols such as pentaerythritol tetra(3-mercaptopropionate), added in concentrations below 10 percent to typical peroxide-amine cured resins, composites with significantly reduced setting time and excellent color stability have been obtained ( ). Dodecyl mercaptan yields comparable results (ll). The free radical addition of the thiol to the double bond of the monomer probably controls the molecular weight of the polymer. 

It is important not to allow the reaction mixture to become appreciably alkaline, since the free base then decomposes rapidly yielding benzyl mercaptan, which has an unpleasant odour. 

Alkyl (or Aryl) 2 4-dinitrophenyl-sulphides (or thioethers) and the corresponding sulphones. Mercaptans react with 2 4-dinitrochlorobenzene in alkaline solution to yield crystalhne thioethers (2 4-dinitrophenyl-sulphides) (I) ... 

Dinitrothiobenzoates. Mercaptans react with 3 5-dinitro-benzoyl chloride in the presence of pyridine as a catalyst to yield 3 5-di-nitrothiobenzoates ... 

Methyl mercaptan adds to acrolein in neatly quantitative yields in the presence of a variety of basic catalysts (72,73). Other aLkylmercaptopropionaldehydes produced by the reaction of acrolein with a mercaptan are known. Table 8 Hsts a variety of these and their boiling points (74). 

Many of these reactions are reversible, and for the stronger nucleophiles they usually proceed the fastest. Typical examples are the addition of ammonia, amines, phosphines, and bisulfite. Alkaline conditions permit the addition of mercaptans, sulfides, ketones, nitroalkanes, and alcohols to acrylamide. Good examples of alcohol reactions are those involving polymeric alcohols such as poly(vinyl alcohol), cellulose, and starch. The alkaline conditions employed with these reactions result in partial hydrolysis of the amide, yielding mixed carbamojdethyl and carboxyethyl products. 

Stabilizer Synthesis. The selected alkyltin chloiide intermediate reacts with either a carboxyhc acid or a mercaptan in the presence of an appropriate base, such as sodium hydroxide, to yield the alkyltin carboxylate or alkyltin mercaptide heat stabihzet. Alternatively, the alkyltin chloride can react with the base to yield the alkyltin oxide, which may or may not be isolated, for subsequent condensation with the selected carboxyhc acid or mercaptan. 

The reaction of aliphatic and aromatic mercaptans with aziridines yields thioethers (117—119). 

The described method of preparation of w-nitrophenyl disulfide is essentially that of Foss and co-workers and is a modification of that reported by Ekbom. The disulfide has been prepared by reaction of potassium ethyl xanthate with w-nitrobenzenedi-azonium chloride solution, followed by hydrolysis to yield the mercaptan, which is subsequently oxidized with potassium ferro-cyanide or dilute nitric acid to the disulfide. ... 

NBD-chloride reacts with nucleophilic compounds (amines, mercaptans etc.) to yield the corresponding 7-substituted 4-nitrobenzofurazan derivatives. 

The striking effect of the catalyst is exemplified by the reaction of pregna-4, 16-diene-3,20-dione (10) with benzyl mercaptan. In the presence of piperidine only conjugate addition occurs to give (11) whereas with pyridine hydrochloride only the 3-benzyl thioenol ether (12) is formed. In the presence of p-toluenesulphonic acid both reactions take place to yield (13). 

The A" -3-keto group can be selectively protected as a thioenol ether in the presence of a 17- or 20-ketone. High yields are obtained with benzyl mercaptan and pyridine hydrochloride as a catalyst. 

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