Ethane-1,1-dithiol is an

organosulfur compound Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur der ...

with formula CH₃CH(SH)₂. It is a colourless smelly liquid that is added to or found in some foods. The compound is an example of a

geminal dithiol In organic chemistry, a dithiol is a type of organosulfur compound with two thiol () functional groups. Their properties are generally similar to those of monothiols in terms of solubility, odor, and volatility. They can be classified according ...

Use

Flavouring uses of ethane-1,1-dithiol may include drinks, oil, gravy, soup, meat, fruit, seasonings, and snacks. Maximum concentrations in use that are generally recognised as safe (GRAS) is five parts per million (ppm) but typical uses are around 0.2 ppm. It is supplied as a 1% solution in

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

, due to its strong offensive smell. In the diluted form with 4% ethyl acetate and ethanol the CAS number is 69382-62-3. Toxicity may be due to metabolism products

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...

and

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic compound, organic chemical compound with the chemical formula, formula , sometimes abbreviated as . It is a colorless liquid or gas, boiling near room temperature. It is one of the most ...

, however as used it has a margin of safety of over 10,000,000. Other ways that it is modified in the body apart from hydrolysis is methylation to 1-methylsulfanyl-ethanethiol, oxidation of the

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

to an ethyl sulfonate,

glucuronidation Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve gly ...

of the sulfur, or combination with

cysteine Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the chemical formula, formula . The thiol side chain in cysteine enables the formation of Disulfide, disulfide bonds, and often participates in enzymatic reactions as ...

by way of a disulfide bridge.

Identifiers

Since it is used in the food industry there are codes issued by various authorities. It is identified as JECFA number 1660. The

Flavor and Extract Manufacturers Association The Flavor and Extract Manufacturers Association (FEMA) is a food industry trade group based in the United States. FEMA was founded in 1909 by several flavor firms in response to the passage of the Pure Food and Drug Act of 1906. Founding members ...

(FEMA) id is 4111. The European designation for the flavouring is Fl 12.293.

Natural occurrence

It can be produced during fermentation of grapes. It is used as a food flavouring. It is found naturally in the scent of

durian The durian () is the edible fruit of several tree species belonging to the genus ''Durio''. There are 30 recognized species, at least nine of which produce edible fruit. ''Durio zibethinus'', native to Borneo and Sumatra, is the only species ...

Properties

The nuclear magnetic resonance spectrum shows three environments for protons, in the ratio of 3:2:1 corresponding to CH₃ SH and CH.

Reactions

Ethane-1,1-dithiol has several reactions known that are important in white wine flavours. In the presence of oxygen, ethane-1,1-dithiol is converted to ''cis''/''trans''-3,6-dimethyl-1,2,4,5-tetrathiane which has a rubbery aroma. This molecule has a ring with four sulfur atoms and two carbons, two ethane-1,1-dithiol molecules become linked at their sulfur atoms with the loss of hydrogen. This can further oxidise to ''cis''/''trans''-3,5-dimethyl-1,2,4-trithiolane which has a meat-like odour. Ethane-1,1-dithiol reacts with hydrogen sulfide to form ''cis''/''trans''-4,7-dimethyl-1,2,3,5,6-pentathiepane, a ring containing five sulfur atoms and two carbons. This has a meaty smell.

Formation

Ethane-1,1-dithiol can be formed in the reaction of

with

. 1-Hydroxyethanethiol is formed as an intermediary.

References

External links

* * * {{DEFAULTSORT:Ethanedithiol, 1,1- Thiols Flavors Foul-smelling chemicals

Use