Thioglycolic acid

"Thioglycolate" redirects here. For the microbiology broth, see thioglycollate broth.

Thioglycolic acid
IUPAC name 2-Sulfanylacetic acid
Other names Mercaptoacetic acid Thioglycolic acid
Identifiers
CAS number	68-11-1 Y
PubChem	1133
ChemSpider	1101 Y
UNII	7857H94KHM Y
KEGG	C02086 Y
ChEBI	CHEBI:30065 Y
ChEMBL	CHEMBL116455 Y
Jmol-3D images	Image 1
SMILES C(C(=O)O)S
InChI InChI=1S/C2H4O2S/c3-2(4)1-5/h5H,1H2,(H,3,4) Y Key: CWERGRDVMFNCDR-UHFFFAOYSA-N Y InChI=1/C2H4O2S/c3-2(4)1-5/h5H,1H2,(H,3,4) Key: CWERGRDVMFNCDR-UHFFFAOYAP
Properties
Molecular formula	C2H4O2S
Molar mass	92.12 g mol−1
Density	1.32 g/cm3
Melting point	-16 °C, 257 K, 3 °F
Boiling point	96 °C at 5 mmHg
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Thioglycolic acid (TGA) is the organic compound HSCH₂CO₂H. It contains both a thiol (mercaptan) and a carboxylic acid. It is a clear liquid with a strong unpleasant odor. It is readily oxidized by air to the corresponding disulfide [SCH₂CO₂H]₂.

TGA was developed in the 1940s for use as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate. TGA is the precursor to ammonium thioglycolate that is used for permanents. TGA and its derivatives break the disulfide bonds in the cortex of hair. One reforms these broken bonds in giving hair a "perm." Alternatively and more commonly, the process leads to depilation as is done commonly in leather processing. It is also used as an acidity indicator, manufacturing of thioglycolates, and in bacteriology for preparation of thioglycolate media.

TGA is also used in the making of tin stabilizers often used in certain polyvinyl chloride products (such as vinyl siding).

TGA, usually as its dianion, forms complexes with metal ions. Such complexes have been used for the detection of iron, molybdenum, silver, and tin.

Thioglycolic acid is used as nucleophile in thioglycolysis reactions used on condensed tannins to study their structure.

See also

• Glycolic acid
• Ammonium thioglycolate