Also found in: Dictionary, Medical.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



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.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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.
The processing of this liquid is necessary because it has a high content of sulphurous mercaptans. Importers have been reluctant to buy condensates from Qatar and Abu Dhabi, so both have opted for large splitters.
Although sulphur is present in many forms in oil, mercaptans are most objectionable due to their obnoxious odour and corrosive action.
Chemicals based on the light fraction of natural mercaptans.
According to AES General Manager Jerry Davis, Vulchur removes hydrogen sulfide (H2S) and mercaptans from wastewater systems two elements that cause serious odor, safety and equipment maintenance issues.
because the Department believes that there is a link between these fines placed with MSW and the production of high amounts of hydrogen sulfide, mercaptans and other reduced sulfur compounds."
The application of these specialty chemicals has the potential to reduce time needed to purge vessels prior to entry and the more environmentally significant capability to scavenge such odorous gases as hydrogen sulfide and mercaptans. As a result of these applications, the safety of the work place is improved and odors are reduced from the processes and waste treatment areas.
They and their partners lift their share of the condensates which, however, contain mercaptans.
The airmoMEDOR, a fully automatic GC with a sulfur selective electrochemical detector, is for routine QC of odiferous trace sulfur components such as [H.sub.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.