Mercaptans


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Mercaptans

 

thioalcohols, thiols, sulfur analogues of alcohols, general formula, RSH, where R is a hydrocarbon radical.

With the exception of methyl mercaptan (boiling point, 6.0°C), the mercaptans are liquids with an unpleasant specific odor. They occur in nature mainly in the products of protein decay. Their weakly acidic properties make mercaptans capable of forming salts, called mercaptides [for example, of mercury— (RS)2Hg—hence the name, from the Late Latin mercurium captans,“mercury-binding”]. Mercaptans are easily oxidized to disulfides (RSSR) and sulfonic acids (RSO3H).

Mercaptans are prepared by the alkylation of hydrosulfides of the alkaline metals: NaSH + RX → RSH + NaX (where R is alkyl and X is a halogen). They are also obtained by the condensation of thiourea S = C(NH2)2 with alkyl halides (RX), followed by the hydrolysis of the resultant S-alkylisothiouronium salts. Thiophenols are also frequently included among the mercaptans.

Mercaptans and their derivatives (salts, sulfides, and disulfides) are used as accelerators in the vulcanization of natural and synthetic rubbers (for example, 2-mercaptobenzothiazole, or Kaptaks), as accelerators in the plastication of rubbers (for ex-ample, pentachlorothiophenol, or Renatsit, and dodecyl mercaptan), in certain medicinal preparations (methionine, Sulfonal), and in insecticides. A mixture of mercaptans (mostly of butyl and amyl mercaptans) is used to add an odor to harmful odorless gases.

References in periodicals archive ?
An example would be naturally occurring methyl mercaptan oxidizing the injected tert-butyl mercaptan blend, resulting in an under-odorized natural gas supply.
As it is shown, in natural gas composition except hydrocarbon it contains mechanical impurities like hydrogen sulfide, carbon dioxide and nitrogen, mercaptans, oxygen, moisture and other compounds that negatively affect on the quality of produced products.
Ali (1987) reported a study on the removal of mercaptans, sulphides, and disulphides from a petroleum oil of 240-360[degrees]C boiling range using 5A and 13X molecular sieves.
The authors review the properties and applications of mercaptans (thiols) in organic synthesis, then describe the composition and properties of C2-C5 mercaptans in a mixture of national origins and describe the synthesis of other materials, explain the synthesis and transformation of functionally situated acids and the synthesis and transformation of products of thioalkylatin of mercaptans C2-C5, testing of applied properties of organic compounds synthesized on the base of the C2-C5 mercaptans mixture, and methods of carrying out experiments.
2]S, mercaptans, sulfides, and others with low or sub-ppb sensitivity.
There is no reference side contamination and the electrodes may be used where sulphides, mercaptans, heavy metal ions or similar materials are present, say Semat of 1 Executive Park, Hatfield Road, St.
Besides the hydrogenation of dienes, ethyl and propyl mercaptans are also removed via thioetherification where the diolefins react with the mercaptans to form olefinic sulfides which are higher boiling and concentrate at the bottom of the tower.
I had found an industrial-strength cologne to mask the pungent mercaptans and now reeked of mint.
is a triazine based product that scavenges hydrogen sulfide and mercaptans.
Many compounds, among them nitroso compounds, mercaptans and their zinc salts, thiocarboxylic acids and their salts, disulphides, sulphenamides, hydrazines, peroxides and metal complexes, are known to have depolymerizing effects[5].
Supply of odorant for natural gas type Tetrahydrothiophene (THT) and Mercaptans liquid mixture (TBM) including transportation and placing directly into service tanks or reserves of Re.