THIOGLYCOLIC ACID

CAS No. : 68-11-1
EC No. : 200-677-4

mercaptoacetic acid; Tiyoglikolik Asit; 68-11-1; 2-Tiyoglikolik Asit; Acetic acid, mercapto-; Sulfanylacetic acid; 2-Mercaptoacetic acid; 2-sulfanylacetic acid; Thioglycollic acid; Thiovanic acid; Mercaptoessigsaeure; Glycolic acid, thio-; thioglycolate; Acide thioglycolique; Glycolic acid, 2-thio-; Mercaptoethanoic acid; USAF CB-35; 2-Mercaptoacetate; mercapto acetic acid; Kyselina thioglykolova; Kyselina merkaptooctova; thioglycolicacid; Thioglykolsaeure; alpha-Mercaptoacetic acid; Thioglycolic acid solution; Acetic acid, 2-mercapto-; Merkaptoessigsaeure; NSC 1894; .alpha.-Mercaptoacetic acid; Acide thioglycolique [French]; mercapto-acetic acid; UNII-7857H94KHM; Kyselina thioglykolova [Czech]; CCRIS 4873; Kyselina merkaptooctova [Czech]; HSDB 2702; EINECS 200-677-4; UN1940; BRN 0506166; AI3-24151; CHEMBL116455; CHEBI:30065; 7857H94KHM; NSC-1894; MFCD00004876; mercaptoacetic acid  ; DSSTox_CID_6141; Mercaptoacetic acid, 98%; DSSTox_RID_78033; DSSTox_GSID_26141; CAS-68-11-1; mercaptoactic acid; 2-mercaptoaceticacid; Sulfanylacetic acid #; HSCH2COOH; HSCH2CO2H; WLN: SH1VQ; EC 200-677-4; ACMC-1BG92; Thioglycolic acid, >=97%; Thioglycolic acid, >=98%; Thioglycolic acid, >=99%; 4-03-00-00600 (Beilstein Handbook Reference); KSC492E2P; AMMONIUM THIOGLY- COLATE; DTXSID8026141; Thioglycolic acid, LR, ~80%; CTK3J2227; CWERGRDVMFNCDR-UHFFFAOYSA-; NSC1894; STR00166; ZINC4658574; Tox21_201717; Tox21_303306; ANW-13583; BDBM50336509; STL264219; AKOS000118940; DB15429; LS-1576; MCULE-8097997001; Thioglycolic acid, for synthesis, 97%; UN 1940; KS-000015P9; NCGC00249103-01; NCGC00257153-01; NCGC00259266-01; NCI60_001579; SC-18319; Thioglycolic acid [UN1940] [Corrosive]; DB-002789; Thioglycolic acid [UN1940] [Corrosive]; FT-0628213; FT-0651867; M0052; NS00003173; 8847-EP2292595A1; 8847-EP2295415A1; 8847-EP2308839A1; 8847-EP2316824A ; C02086; 102887-EP2301938A1; 119037-EP2272817A1; 119037-EP2272843A1; 119037-EP2281817A1; 119037-EP2287155A1; 119037-EP2287160A1; 119037-EP2292597A1; 119037-EP2295414A1; 119037-EP2298756A1; 119037-EP2374786A1; Q414738; Thioglycolic acid solution, ~70 % (w/w) in H2O; F2191-0214; Thioglycolic acid solution, ~80% in H2O, for spectrophotometric det. of palladium, iron, uranium(VI), molybdates and nitrites; Thioglycolic acid; Tiyoglikolik Asit; tioglikolik asit; tioglik asit; THIGLYCOLIK ACID; TIGLYCOLIC ACID; TIOGYLIC ACID; GLYCOLIC ACID; thiglicolic acid; mercaptoacetic acid; thioglycolic acid; 68-11-1; 2-Thioglycolic acid; Acetic acid, mercapto-; Sulfanylacetic acid; 2-Mercaptoacetic acid; 2-sulfanylacetic acid; Thioglycollic acid; Thiovanic acid; Mercaptoessigsaeure; Glycolic acid, thio-; thioglycolate; Acide thioglycolique; Glycolic acid, 2-thio-; Mercaptoethanoic acid; USAF CB-35; 2-Mercaptoacetate; mercapto acetic acid; Kyselina thioglykolova; Kyselina merkaptooctova; thioglycolicacid; Thioglykolsaeure; alpha-Mercaptoacetic acid; Thioglycolic acid solution; Acetic acid, 2-mercapto-; Merkaptoessigsaeure; NSC 1894; .alpha.-Mercaptoacetic acid; Acide thioglycolique [French]; mercapto-acetic acid; UNII-7857H94KHM; Kyselina thioglykolova [Czech]; CCRIS 4873; Kyselina merkaptooctova [Czech]; HSDB 2702; EINECS 200-677-4; UN1940; BRN 0506166; AI3-24151; CHEMBL116455; CHEBI:30065; 7857H94KHM; NSC-1894; MFCD00004876; mercaptoacetic acid  ; DSSTox_CID_6141; Mercaptoacetic acid, 98%; DSSTox_RID_78033; DSSTox_GSID_26141; CAS-68-11-1; mercaptoactic acid; 2-mercaptoaceticacid; Sulfanylacetic acid #; HSCH2COOH; HSCH2CO2H; WLN: SH1VQ; EC 200-677-4; ACMC-1BG92; Thioglycolic acid, >=97%; Thioglycolic acid, >=98%; Thioglycolic acid, >=99%; 4-03-00-00600 (Beilstein Handbook Reference); KSC492E2P; AMMONIUM THIOGLY- COLATE; DTXSID8026141; Thioglycolic acid, LR, ~80%; CTK3J2227; CWERGRDVMFNCDR-UHFFFAOYSA-; NSC1894; STR00166; ZINC4658574; Tox21_201717; Tox21_303306; ANW-13583; BDBM50336509; STL264219; AKOS000118940; DB15429; LS-1576; MCULE-8097997001; Thioglycolic acid, for synthesis, 97%; UN 1940; KS-000015P9; NCGC00249103-01; NCGC00257153-01; NCGC00259266-01; NCI60_001579; SC-18319; Thioglycolic acid [UN1940] [Corrosive]; DB-002789; Thioglycolic acid [UN1940] [Corrosive]; FT-0628213; FT-0651867; M0052; NS00003173; 8847-EP2292595A1; 8847-EP2295415A1; 8847-EP2308839A1; 8847-EP2316824A ; C02086; 102887-EP2301938A1; 119037-EP2272817A1; 119037-EP2272843A1; 119037-EP2281817A1; 119037-EP2287155A1; 119037-EP2287160A1; 119037-EP2292597A1; 119037-EP2295414A1; 119037-EP2298756A1; 119037-EP2374786A1; Q414738; Thioglycolic acid solution, ~70 % (w/w) in H2O; F2191-0214; Thioglycolic acid solution, ~80% in H2O, for spectrophotometric det. of palladium, iron, uranium(VI), molybdates and nitrites; Thioglycolic acid; Tiyoglikolik Asit; tioglikolik asit; tioglik asit; THIGLYCOLIK ACID; TIGLYCOLIC ACID; TIOGYLIC ACID; GLYCOLIC ACID; thiglicolic acid; mercaptoacetic acid; thioglycolic acid; 68-11-1; 2-Thioglycolic acid; Acetic acid, mercapto-; Sulfanylacetic acid; 2-Mercaptoacetic acid; 2-sulfanylacetic acid; Thioglycollic acid; Thiovanic acid; Mercaptoessigsaeure; Glycolic acid, thio-; thioglycolate; Acide thioglycolique; Glycolic acid, 2-thio-; Mercaptoethanoic acid; USAF CB-35; 2-Mercaptoacetate; mercapto acetic acid; Kyselina thioglykolova; Kyselina merkaptooctova; thioglycolicacid; Thioglykolsaeure; alpha-Mercaptoacetic acid; Thioglycolic acid solution; Acetic acid, 2-mercapto-; Merkaptoessigsaeure; NSC 1894; .alpha.-Mercaptoacetic acid; Acide thioglycolique [French]; mercapto-acetic acid; UNII-7857H94KHM; Kyselina thioglykolova [Czech]; CCRIS 4873; Kyselina merkaptooctova [Czech]; HSDB 2702; EINECS 200-677-4; UN1940; BRN 0506166; AI3-24151; CHEMBL116455; CHEBI:30065; 7857H94KHM; NSC-1894; MFCD00004876; mercaptoacetic acid  ; DSSTox_CID_6141; Mercaptoacetic acid, 98%; DSSTox_RID_78033; DSSTox_GSID_26141; CAS-68-11-1; mercaptoactic acid; 2-mercaptoaceticacid; Sulfanylacetic acid #; HSCH2COOH; HSCH2CO2H; WLN: SH1VQ; EC 200-677-4; ACMC-1BG92; Thioglycolic acid, >=97%; Thioglycolic acid, >=98%; Thioglycolic acid, >=99%; 4-03-00-00600 (Beilstein Handbook Reference); KSC492E2P; AMMONIUM THIOGLY- COLATE; DTXSID8026141; Thioglycolic acid, LR, ~80%; CTK3J2227; CWERGRDVMFNCDR-UHFFFAOYSA-; NSC1894; STR00166; ZINC4658574; Tox21_201717; Tox21_303306; ANW-13583; BDBM50336509; STL264219; AKOS000118940; DB15429; LS-1576; MCULE-8097997001; Thioglycolic acid, for synthesis, 97%; UN 1940; KS-000015P9; NCGC00249103-01; NCGC00257153-01; NCGC00259266-01; NCI60_001579; SC-18319; Thioglycolic acid [UN1940] [Corrosive]; DB-002789; Thioglycolic acid [UN1940] [Corrosive]; FT-0628213; FT-0651867; M0052; NS00003173; 8847-EP2292595A1; 8847-EP2295415A1; 8847-EP2308839A1; 8847-EP2316824A ; C02086; 102887-EP2301938A1; 119037-EP2272817A1; 119037-EP2272843A1; 119037-EP2281817A1; 119037-EP2287155A1; 119037-EP2287160A1; 119037-EP2292597A1; 119037-EP2295414A1; 119037-EP2298756A1; 119037-EP2374786A1; Q414738; Thioglycolic acid solution, ~70 % (w/w) in H2O; F2191-0214; Thioglycolic acid solution, ~80% in H2O, for spectrophotometric det. of palladium, iron, uranium(VI), molybdates and nitrites; Thioglycolic acid; Tiyoglikolik Asit; tioglikolik asit; tioglik asit; THIGLYCOLIK ACID; TIGLYCOLIC ACID; TIOGYLIC ACID; GLYCOLIC ACID; thiglicolic acid; mercaptoacetic acid; thioglycolic acid; 68-11-1; 2-Thioglycolic acid; Acetic acid, mercapto-; Sulfanylacetic acid; 2-Mercaptoacetic acid; 2-sulfanylacetic acid; Thioglycollic acid; Thiovanic acid; Mercaptoessigsaeure; Glycolic acid, thio-; thioglycolate; Acide thioglycolique; Glycolic acid, 2-thio-; Mercaptoethanoic acid; USAF CB-35; 2-Mercaptoacetate; mercapto acetic acid; Kyselina thioglykolova; Kyselina merkaptooctova; thioglycolicacid; Thioglykolsaeure; alpha-Mercaptoacetic acid; Thioglycolic acid solution; Acetic acid, 2-mercapto-; Merkaptoessigsaeure; NSC 1894; .alpha.-Mercaptoacetic acid; Acide thioglycolique [French]; mercapto-acetic acid; UNII-7857H94KHM; Kyselina thioglykolova [Czech]; CCRIS 4873; Kyselina merkaptooctova [Czech]; HSDB 2702; EINECS 200-677-4; UN1940; BRN 0506166; AI3-24151; CHEMBL116455; CHEBI:30065; 7857H94KHM; NSC-1894; MFCD00004876; mercaptoacetic acid  ; DSSTox_CID_6141; Mercaptoacetic acid, 98%; DSSTox_RID_78033; DSSTox_GSID_26141; CAS-68-11-1; mercaptoactic acid; 2-mercaptoaceticacid; Sulfanylacetic acid #; HSCH2COOH; HSCH2CO2H; WLN: SH1VQ; EC 200-677-4; ACMC-1BG92; Thioglycolic acid, >=97%; Thioglycolic acid, >=98%; Thioglycolic acid, >=99%; 4-03-00-00600 (Beilstein Handbook Reference); KSC492E2P; AMMONIUM THIOGLY- COLATE; DTXSID8026141; Thioglycolic acid, LR, ~80%; CTK3J2227; CWERGRDVMFNCDR-UHFFFAOYSA-; NSC1894; STR00166; ZINC4658574; Tox21_201717; Tox21_303306; ANW-13583; BDBM50336509; STL264219; AKOS000118940; DB15429; LS-1576; MCULE-8097997001; Thioglycolic acid, for synthesis, 97%; UN 1940; KS-000015P9; NCGC00249103-01; NCGC00257153-01; NCGC00259266-01; NCI60_001579; SC-18319; Thioglycolic acid [UN1940] [Corrosive]; DB-002789; Thioglycolic acid [UN1940] [Corrosive]; FT-0628213; FT-0651867; M0052; NS00003173; 8847-EP2292595A1; 8847-EP2295415A1; 8847-EP2308839A1; 8847-EP2316824A ; C02086; 102887-EP2301938A1; 119037-EP2272817A1; 119037-EP2272843A1; 119037-EP2281817A1; 119037-EP2287155A1; 119037-EP2287160A1; 119037-EP2292597A1; 119037-EP2295414A1; 119037-EP2298756A1; 119037-EP2374786A1; Q414738; Thioglycolic acid solution, ~70 % (w/w) in H2O; F2191-0214; Thioglycolic acid solution, ~80% in H2O, for spectrophotometric det. of palladium, iron, uranium(VI), molybdates and nitrites; Thioglycolic acid; Tiyoglikolik Asit; tioglikolik asit; tioglik asit; THIGLYCOLIK ACID; TIGLYCOLIC ACID; TIOGYLIC ACID; GLYCOLIC ACID; thiglicolic acid; mercaptoacetic acid; thioglycolic acid; 68-11-1; 2-Thioglycolic acid; Acetic acid, mercapto-; Sulfanylacetic acid; 2-Mercaptoacetic acid; 2-sulfanylacetic acid; Thioglycollic acid; Thiovanic acid; Mercaptoessigsaeure; Glycolic acid, thio-; thioglycolate; Acide thioglycolique; Glycolic acid, 2-thio-; Mercaptoethanoic acid; USAF CB-35; 2-Mercaptoacetate; mercapto acetic acid; Kyselina thioglykolova; Kyselina merkaptooctova; thioglycolicacid; Thioglykolsaeure; alpha-Mercaptoacetic acid; Thioglycolic acid solution; Acetic acid, 2-mercapto-; Merkaptoessigsaeure; NSC 1894; .alpha.-Mercaptoacetic acid; Acide thioglycolique [French]; mercapto-acetic acid; UNII-7857H94KHM; Kyselina thioglykolova [Czech]; CCRIS 4873; Kyselina merkaptooctova [Czech]; HSDB 2702; EINECS 200-677-4; UN1940; BRN 0506166; AI3-24151; CHEMBL116455; CHEBI:30065; 7857H94KHM; NSC-1894; MFCD00004876; mercaptoacetic acid  ; DSSTox_CID_6141; Mercaptoacetic acid, 98%; DSSTox_RID_78033; DSSTox_GSID_26141; CAS-68-11-1; mercaptoactic acid; 2-mercaptoaceticacid; Sulfanylacetic acid #; HSCH2COOH; HSCH2CO2H; WLN: SH1VQ; EC 200-677-4; ACMC-1BG92; Thioglycolic acid, >=97%; Thioglycolic acid, >=98%; Thioglycolic acid, >=99%; 4-03-00-00600 (Beilstein Handbook Reference); KSC492E2P; AMMONIUM THIOGLY- COLATE; DTXSID8026141; Thioglycolic acid, LR, ~80%; CTK3J2227; CWERGRDVMFNCDR-UHFFFAOYSA-; NSC1894; STR00166; ZINC4658574; Tox21_201717; Tox21_303306; ANW-13583; BDBM50336509; STL264219; AKOS000118940; DB15429; LS-1576; MCULE-8097997001; Thioglycolic acid, for synthesis, 97%; UN 1940; KS-000015P9; NCGC00249103-01; NCGC00257153-01; NCGC00259266-01; NCI60_001579; SC-18319; Thioglycolic acid [UN1940] [Corrosive]; DB-002789; Thioglycolic acid [UN1940] [Corrosive]; FT-0628213; FT-0651867; M0052; NS00003173; 8847-EP2292595A1; 8847-EP2295415A1; 8847-EP2308839A1; 8847-EP2316824A ; C02086; 102887-EP2301938A1; 119037-EP2272817A1; 119037-EP2272843A1; 119037-EP2281817A1; 119037-EP2287155A1; 119037-EP2287160A1; 119037-EP2292597A1; 119037-EP2295414A1; 119037-EP2298756A1; 119037-EP2374786A1; Q414738; Thioglycolic acid solution, ~70 % (w/w) in H2O; F2191-0214; Thioglycolic acid solution, ~80% in H2O, for spectrophotometric det. of palladium, iron, uranium(VI), molybdates and nitrites; Thioglycolic acid; Tiyoglikolik Asit; tioglikolik asit; tioglik asit; THIGLYCOLIK ACID; TIGLYCOLIC ACID; TIOGYLIC ACID; GLYCOLIC ACID; thiglicolic acid; mercaptoacetic acid; thioglycolic acid; 68-11-1; 2-Thioglycolic acid; Acetic acid, mercapto-; Sulfanylacetic acid; 2-Mercaptoacetic acid; 2-sulfanylacetic acid; Thioglycollic acid; Thiovanic acid; Mercaptoessigsaeure; Glycolic acid, thio-; thioglycolate; Acide thioglycolique; Glycolic acid, 2-thio-; Mercaptoethanoic acid; USAF CB-35; 2-Mercaptoacetate; mercapto acetic acid; Kyselina thioglykolova; Kyselina merkaptooctova; thioglycolicacid; Thioglykolsaeure; alpha-Mercaptoacetic acid; Thioglycolic acid solution; Acetic acid, 2-mercapto-; Merkaptoessigsaeure; NSC 1894; .alpha.-Mercaptoacetic acid; Acide thioglycolique [French]; mercapto-acetic acid; UNII-7857H94KHM; Kyselina thioglykolova [Czech]; CCRIS 4873; Kyselina merkaptooctova [Czech]; HSDB 2702; EINECS 200-677-4; UN1940; BRN 0506166; AI3-24151; CHEMBL116455; CHEBI:30065; 7857H94KHM; NSC-1894; MFCD00004876; mercaptoacetic acid  ; DSSTox_CID_6141; Mercaptoacetic acid, 98%; DSSTox_RID_78033; DSSTox_GSID_26141; CAS-68-11-1; mercaptoactic acid; 2-mercaptoaceticacid; Sulfanylacetic acid #; HSCH2COOH; HSCH2CO2H; WLN: SH1VQ; EC 200-677-4; ACMC-1BG92; Thioglycolic acid, >=97%; Thioglycolic acid, >=98%; Thioglycolic acid, >=99%; 4-03-00-00600 (Beilstein Handbook Reference); KSC492E2P; AMMONIUM THIOGLY- COLATE; DTXSID8026141; Thioglycolic acid, LR, ~80%; CTK3J2227; CWERGRDVMFNCDR-UHFFFAOYSA-; NSC1894; STR00166; ZINC4658574; Tox21_201717; Tox21_303306; ANW-13583; BDBM50336509; STL264219; AKOS000118940; DB15429; LS-1576; MCULE-8097997001; Thioglycolic acid, for synthesis, 97%; UN 1940; KS-000015P9; NCGC00249103-01; NCGC00257153-01; NCGC00259266-01; NCI60_001579; SC-18319; Thioglycolic acid [UN1940] [Corrosive]; DB-002789; Thioglycolic acid [UN1940] [Corrosive]; FT-0628213; FT-0651867; M0052; NS00003173; 8847-EP2292595A1; 8847-EP2295415A1; 8847-EP2308839A1; 8847-EP2316824A ; C02086; 102887-EP2301938A1; 119037-EP2272817A1; 119037-EP2272843A1; 119037-EP2281817A1; 119037-EP2287155A1; 119037-EP2287160A1; 119037-EP2292597A1; 119037-EP2295414A1; 119037-EP2298756A1; 119037-EP2374786A1; Q414738; Thioglycolic acid solution, ~70 % (w/w) in H2O; F2191-0214; Thioglycolic acid solution, ~80% in H2O, for spectrophotometric det. of palladium, iron, uranium(VI), molybdates and nitrites; Thioglycolic acid; Tiyoglikolik Asit; tioglikolik asit; tioglik asit; THIGLYCOLIK ACID; TIGLYCOLIC ACID; TIOGYLIC ACID; GLYCOLIC ACID; thiglicolic acid; tiyoglikolik asit; tihoglikolik asid; tuyoglikolik asit

Thioglycolic acid

Thioglycolic acid appears as a colorless liquid with an unpleasant odor. Density 1.325 g / cm3. Used to make permanent wave solutions and depilatories. Corrosive to metals and tissue.

Thioglycolic acid is a sulfur-containing carboxylic acid. It is a conjugate acid of a thioglycolate(1-).

Thioglycolic acid is under investigation in clinical trial NCT03238105 (Treatment of Periorbicular Hyperchromia Comparing 10% Thioglycolic Acid Peeling Versus Pulsed Intense Light).

Thioglycolic acid[1]
Thioglycolic acid.png
Space-filling model of thioglycolic acid
Names
Preferred IUPAC name
Sulfanylacetic acid
Other names
2-Sulfanylacetic acid
2-Mercaptoacetic acid
Acetyl mercaptan
Mercaptoacetate
Mercaptoacetic acid
Thioglycolic acid
Thiovanic acid[2]
Identifiers
CAS Number    
68-11-1 check
3D model (JSmol)    
Interactive image
ChEBI    
CHEBI:30065 check
ChEMBL    
ChEMBL116455 check
ChemSpider    
1101 check
ECHA InfoCard    100.000.616
KEGG    
C02086 check
PubChem CID    
1133
UNII    
7857H94KHM check
CompTox Dashboard (EPA)    
DTXSID802614

Properties
Chemical formula    C2H4O2S
Molar mass    92.11 g·mol−1
Appearance    colorless, clear liquid[3]
Odor    strong, disagreeable[3]
Density    1.32 g/cm3
Melting point    −16 °C (3 °F; 257 K)
Boiling point    96 °C (205 °F; 369 K) at 5 mmHg
Solubility in water    miscible[3]
Vapor pressure    10 mmHg (17.8°C)[3]
Magnetic susceptibility (χ)    -50.0·10−6 cm3/mol
Hazards
Flash point    > 110 °C; 230 °F; 383 K [3]
Explosive limits    5.9%-?[3]
NIOSH (US health exposure limits):
PEL (Permissible)    none[3]
REL (Recommended)    TWA 1 ppm (4 mg/m3) [skin][3]
IDLH (Immediate danger)    N.D.[3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Thioglycolic acid (TGA) is the organic compound HSCH2CO2H. Thioglycolic acid is often called mercaptoacetic acid (MAA). It contains both a thiol (mercaptan) and carboxylic acid functional groups. It is a colorless liquid with a strongly unpleasant odor. Thioglycolic acid is miscible with polar organic solvents.

Uses
Thioglycolic acid is used as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate. Thioglycolic acid is the precursor to ammonium thioglycolate that is used for permanents. Thioglycolic acid 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.[5] In fact thioglycolysis reactions used on condensed tannins to study their structure.

Organotin derivatives of thioglycolic acid isooctyl esters are widely used as stabilizers for PVC. These species have the formula R2Sn(SCH2CO2C8H17)2.[5]

Applying Thioglycolic acid can soften nails and then fix pincer nails in the correct position.

Sodium thioglycolate is a component of a special bacterial growth media : thioglycolate broth. It is also used in so-called "fallout remover"[6] or "wheel cleaner" to remove iron oxide residue from rims.[7] Ferrous iron combines with thioglycolate to form red-violet[8] ferric thioglycolate.[9][10]

Production
Thioglycolic acid is prepared by reaction of sodium or potassium chloracetate with alkali metal hydrosulfide in aqueous medium.[11] It can be also prepared via the Bunte salt obtained by reaction of sodium thiosulfate with chloroacetic acid:[5][12]

ClCH2CO2H + Na2S2O3 → Na[O3S2CH2CO2H] + NaCl
Na[O3S2CH2CO2H] + H2O → HSCH2CO2H + NaHSO4
Reactions
Thioglycolic acid with a pKa of 3.83 [5] is about 10 times stronger an acid than acetic acid (pKa 4.76):

HSCH2CO2H → HSCH2CO2− + H+
The second ionization has a pKa of 9.3:

HSCH2CO2− → −SCH2CO2− + H+
Thioglycolic acid is a reducing agent, especially at higher pH. It oxidizes to the corresponding disulfide (2-[(carboxymethyl)disulfanyl]acetic acid or dithiodiglycolic acid):

2 HSCH2CO2H + "O" → [SCH2CO2H]2 + H2O
With metal ions
Thioglycolic acid, 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 reacts with diethyl acetylmalonate to form acetylmercaptoacetic acid and diethyl malonate, the reducing agent in conversion of Fe(III) to Fe(II).[13]

History
Scientist David R. Goddard, in the early 1930s, identified Thioglycolic acid as a useful reagent for reducing the disulfide bonds in proteins, including keratin (hair protein), while studying why protease enzymes could not easily digest hair, nails, feathers, and such. He realized that while the disulfide bonds, which stabilize proteins by cross-linking, were broken, the structures containing these proteins could be reshaped easily, and that they would retain this shape after the disulfide bonds were allowed to re-form.[14] Thioglycolic acid was developed in the 1940s for use as a chemical depilatory.

Safety and detection
The LD50 (oral, rat) is 261 mg/kg,[5] LC50 inhalation for rat is 21 mg/m3 for 4 h, and LD50 dermal for rabbit is 848 mg/kg.[15] Mercaptoacetic acid in hair waving and depilatory products containing other mercapto acids can be identified by using thin-layer chromatography and gas chromatography.[16][17] MAA also has been identified by using potentiometric titration with silver nitrate solution.[18]

See also
Glycolic acid
Ammonium thioglycolate
Thiolactic acid

Thioglycolic acid   IUPAC Name 2-sulfanylacetic acid
Thioglycolic acid   InChI InChI=1S/C2H4O2S/c3-2(4)1-5/h5H,1H2,(H,3,4)
Thioglycolic acid   InChI Key CWERGRDVMFNCDR-UHFFFAOYSA-N 
Thioglycolic acid   Canonical SMILES C(C(=O)O)S
Thioglycolic acid   Molecular Formula C2H4O2S
Thioglycolic acid   CAS 68-11-1
Thioglycolic acid   Deprecated CAS 57755-20-1, 7283-42-3
Thioglycolic acid   European Community (EC) Number 200-677-4
Thioglycolic acid   ICSC Number 0915
Thioglycolic acid   NSC Number 1894
Thioglycolic acid   RTECS Number AI5950000
Thioglycolic acid   UN Number 1940
Thioglycolic acid   UNII 7857H94KHM
Thioglycolic acid   DSSTox Substance ID DTXSID8026141
Thioglycolic acid   Physical Description Liquid
Thioglycolic acid   Color/Form Colorless liquid
Thioglycolic acid   Odor Strong, unpleasant odor 
Thioglycolic acid   Boiling Point 248 °F at 20 mm Hg 
Thioglycolic acid   Melting Point 2.3 °F 
Thioglycolic acid   Flash Point 235 °F
Thioglycolic acid   Solubility greater than or equal to 100 mg/mL at 64° F
Thioglycolic acid   Density 1.3253 at 68 °F
Thioglycolic acid   Vapor Density 3.18 (Air = 1)
Thioglycolic acid   Vapor Pressure 10 mm Hg at 64 °F
Thioglycolic acid   LogP 0.09 (LogP)
Thioglycolic acid   Stability/Shelf Life Stable under recommended storage conditions.
Thioglycolic acid   Autoignition Temperature 350 °C
Thioglycolic acid   Decomposition When heated to decomp it emits toxic fumes of /sulfur oxides/.
Thioglycolic acid   Viscosity 6.55 mPa.s (= cP) at 20 °C
Thioglycolic acid   Corrosivity Corrosive
Thioglycolic acid   Heat of Combustion 1450 kJ/mol
Thioglycolic acid   Heat of Vaporization 627.2 J/g
Thioglycolic acid   Refractive Index Index of refraction: 1.5080 at 20 °C/D
Thioglycolic acid   Dissociation Constants pKa = 3.55
 
Thioglycolic acid   Molecular Weight 92.12 g/mol 
Thioglycolic acid   XLogP3 0.1 
Thioglycolic acid   Hydrogen Bond Donor Count 2 
Thioglycolic acid   Hydrogen Bond Acceptor Count 3 
Thioglycolic acid   Rotatable Bond Count 1 
Thioglycolic acid   Exact Mass 91.993201 g/mol 
Thioglycolic acid   Monoisotopic Mass 91.993201 g/mol 
Thioglycolic acid   Topological Polar Surface Area 38.3 Ų 
Thioglycolic acid   Heavy Atom Count 5 
Thioglycolic acid   Formal Charge 0 
Thioglycolic acid   Complexity 42.9 
Thioglycolic acid   Isotope Atom Count 0 
Thioglycolic acid   Defined Atom Stereocenter Count 0 
Thioglycolic acid   Undefined Atom Stereocenter Count 0 
Thioglycolic acid   Defined Bond Stereocenter Count 0 
Thioglycolic acid   Undefined Bond Stereocenter Count 0 
Thioglycolic acid   Covalently-Bonded Unit Count 1 
Thioglycolic acid   Compound Is Canonicalized Yes
 

Thioglycolic acid   is the organic compound HSCH2CO2H. Thioglycolic acid   is often called mercaptoacetic acid (MAA). It contains both a thiol (mercaptan) and carboxylic acid functional groups. It is a colorless liquid with a strongly unpleasant odor. Thioglycolic acid   is miscible with polar organic solvents.Thioglycolic acid   is used as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate. Thioglycolic acid   is the precursor to ammonium thioglycolate that is used for permanents. Thioglycolic acid   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.[5] In fact thioglycolysis reactions used on condensed tannins to study their structure.Organotin derivatives of thioglycolic acid isooctyl esters are widely used as stabilizers for PVC. These species have the formula R2Sn(SCH2CO2C8H17)2.Applying Thioglycolic acid   can soften nails and then fix pincer nails in the correct position.Sodium thioglycolate is a component of a special bacterial growth media : thioglycolate broth. It is also used in so-called "fallout remover"[6] or "wheel cleaner" to remove iron oxide residue from rims.[7] Ferrous iron combines with thioglycolate to form red-violet[8] ferric thioglycolate.Thioglycolic acid is prepared by reaction of sodium or potassium chloracetate with alkali metal hydrosulfide in aqueous medium.[11] It can be also prepared via the Bunte salt obtained by reaction of sodium thiosulfate with chloroacetic acid:[5][12]Thioglycolic acid, 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 reacts with diethyl acetylmalonate to form acetylmercaptoacetic acid and diethyl malonate, the reducing agent in conversion of Fe(III) to Fe(II).Thioglycolic acid :Understanding the risk of Specific Chemicals of Interest Thioglycolic acid can cause severe burns and chemical injuries when it enters in contact with the skin, eye, digestive or respiratory tracts. It is corrosive and can even induce a systemic toxicity.However, thioglycolic acid is still widely used in domestic products such as depilatory creams and by hairdressers for "perms". Let's understand the risk it presents.Thioglycolic acid is a colorless liquid with a strong, typical mercaptan disagreeable odor (although olfactory fatigue may occur) which is used in cosmetic formulations including permanent wave solutions and depilatories, in pharmaceutical manufacture, and as a stabilizer for vinyl plastics. A recent use is as a capping or stabilizing agent for Cd/Te quantum microdots (QDs). It is a member of the thioglycolate chemical class.Thioglycolic acid is a reactive reducing agent: it is readily oxidized on exposure to air. Thioglycolic acid is also a weak acid due to the presence of a carboxylic acid function in the molecule.Because of its high reactivity, it is incompatible with air, strong oxidizers, bases, active metals such as sodium, potassium, magnesium, and calcium (for examples).Thioglycolic acid is considered to be a Class IIIB Combustible Liquid, therefore, it is not considered to be flammable.Thioglycolic acid is a contact irritant or corrosive substance of the eyes, skin, and mucous membranes.It is known to cause severe skin burns and eye damages. The European Chemical Agency (ECHA) recommends to label it with the H314 risk phrase. (full classification) In case of cutaneous or ocular exposure to thioglycolic acid, corneal damage and chemical skin injury with blister formation has occurred.In one reported case where thioglycolic acid liquid was splashed into the eyes bilaterally and also on the skin of the face, legs, and arms, second-degree (blistering) injury of the skin areas occurred. By two hours, the corneas were clouded (one worse than the other) and the conjunctiva was edematous. It took several months for the corneas and conjunctiva to heal, and some vascularization occurred resulting in mild visual impairment.Experimental animal studies have shown significant eye and skin lesions from direct contact. Additionally, the thioglycolates class has been shown to be rapidly absorbed through the skin in experimental animals, resulting in systemic toxicity.This is somewhat corroborated by a single case report of a 79-year-old woman who developed significant systemic toxicity including toxic pulmonary edema, and sequelae of hemorrhagic fibrinous tracheobronchitis, acute respiratory distress syndrome (ARDS), lactic acidosis, kidney and liver failure, rhabdomyolysis, and bleeding from the mucous membranes following exposure to a home permanent waving solution containing thioglycolic acid. This exposure, however, may have been primaryily by inhalation rather than dermal contact.Thioglycolic acid also presents liver and digestive tract toxicity when it is ingested.As part of cosmetic formulations, thioglycolic acid has been associated with development of irritant or allergic contact dermatitis, particularly amongst hairdressers exposed chronically.Thioglycolic acid was not mutagenic in various Salmonella tyhrimurium strains with or without metabolic activation.There is currently no evidence that thioglycolic acid is a carcinogen.A series of preliminary tests in which an attempt was made to agglomerate sulfurized mineral pyrite in the presence of an agglomeration suppressant showed that the following materials were effective suppressants: Thioglycolic acid  , thiolactic acid (TLA), mercaptosuccinic acid (MSA), 3-mercaptopropionic acid (MPA), and 2-mercapto-ethane-sulfonic acid (MES). Typical results are indicated in Fig. 1 for sulfurized mineral pyrite in the presence of different concentrations of Thioglycolic acid   at pH 4.5. A baseline experiment conducted without Thioglycolic acid   showed that the pyrite was agglomerated readily with heptane since the turbidity of the particle suspension decreased steadily as the heptane dosag increased. In the presence of 0.0002 M Thioglycolic acid  , the turbidity was greater than without Thioglycolic acid  , indicating that the particles were dispersed more completely. However, the turbidity still decreased as increasing amounts of heptane were added, which showed that agglomeration was occurring. But in the presence of 0.001 M and larger concentrations of Thioglycolic acid  , the turbidity only increased as more heptane was added. This trend was due apparently to the dispersion of heptane droplets in the aqueous suspension which meant that the heptane was not adhering to the pyrite. Similar results were obtained at pH 7.5 and pH 10.4 except that a Thioglycolic acid   concentration of only 0.0002 M was sufficient to prevent agglomeration. Similar results were also realized with sulfurized coal-derived pyrite. A baseline experiment showed that this material was readily agglomerated without a suppressant, whereas agglomeration was suppressed by Thioglycolic acid  .In order to study the macromolecular properties of lignin such as molecular weight, density, shape, crystallinity, etc. a detailed structural analysis is required. This is generally done by using various nondegradative techniques that make use of various chemicals such as Thioglycolic acid   and ACBR which add functional groups to lignin polymer, modify its properties, thereby allowing the quantification of the content/composition without disturbing the native structure of the polymer [42,43]. In these techniques, derivatization of lignin is first done by adding functional groups to the β-O′-4 units resulting in a change in its solubility. For further quantification, lignin is solubilized in appropriate solvents and the content is determined by using UV absorbance. Care must be taken to maintain the native structure of the polymer while performing derivatization and solubilization procedures. Later, the solubilized lignin is analyzed to study the size and conformation of polymer by size-exclusion chromatography. There are some limitations of using size-exclusion chromatography such as lengthy elution time and not so accurate molar mass determination as it is based on UV absorbance. Moreover, the detailed structure/conformation of the polymer cannot be studied accurately using UV absorption method alone [44]. Therefore, use of dynamic light scattering method has emerged. This method is based on the principle of illuminating the sample with a beam of laser light and the fluctuations of the scattered light are detected and analyzed at a known scattering angle by a fast photon detector that can determine the molar mass and shape distribution of the polymer accurately [44]. Therefore, the use of an appropriate extraction method which is nondegradative along with size-exclusion chromatography is used to determine the lignin structure.Proteins are successfully conjugated to the surface of nanoparticles via covalent bonding between the protein reactive moieties (such as carboxyl and amino groups) and the functional groups conferred by the capping agent of nanoparticles.Carbodiimide coupling is the most commonly used reaction for protein-nanoparticle conjugation via amide or ester bond formation. Arginine is employed to decorate the surface of iron oxide nanoparticles (IONPs) to provide free amine groups giving an opportunity for amide bond formation with the carboxylic groups of bovine serum albumin (BSA). Similarly, the carboxylic groups of both gadolinium diethylene triamine pentaacetic acid (Gd-DTPA) complexes and thioglycolic acid-functionalized CdTe QDs (Thioglycolic acid  -QDs) are conjugated via carbodiimide coupling to the amino groups of HSA and BSA, respectively. The use of ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) as a linker to conjugate Thioglycolic acid  -QDs to BSA is found to be comparable to bifunctional crosslinkers, e.g., glutaraldehyde, while avoiding their toxicity. Conjugation efficiency can be enhanced by cationization of albumin by replacing the side-chain carboxylic groups with ethylenediamine followed by linking to the surface carboxylic groups of the citrate-capped magnetic nanoparticles (MNPs), thus elaborating albumin-magnetic nanohybrids. Common linkers like succinic anhydride is used to conjugate mesoporous silica nanoparticles (MSNs) to the proteins; gelatin, BSA, and lysozyme leading to fabrication of MSN-protein nanohybrids. Amino-functionalized MSNs are covalently decorated with succinic anhydride molecules producing carboxylated MSNs followed by protein immobilization via their amino groups onto the surface of carboxylated MSNs by carbodiimide coupling. Albumin and gelatin are coupled to MSNs in higher amounts compared to lysozyme, probably due to their higher molecular weight. Another technique thiol-maleimide coupling was also utilized to link thiolated proteins to the surface of maleimide-derivatized inorganic nanoparticles. Thiolated transferrin (Tf) was successfully attached to PEG-maleimide-activated HSA-Gd-DTPA nanoparticles with 84% Tf binding efficiency. Another conjugation method involves the formation of Schiff-base bonds between residual aldehyde groups on the surface of inorganic nanoparticles and amine groups of the proteins. Treatment of amine-modified MSNs with glutaraldehyde and further reaction of the resulting aldehyde-functionalized MSNs with gelatin leads to the fabrication of gelatin corona on the surface of MSNs [45].Thioglycolic acid and the ethers of glycolic acid may have the added benefits of a higher boiling point and possibly increased water solubility [11]. A higher boiling point means the additive will not distill into the distillate fractions in the crude unit and cause corrosion or product quality concerns. The higher water solubility also favors removal of the additive from the crude oil in the desalter and reduces the amount that may reach the downstream processing units. The addition of glycolic acid (ie, hydroxyacetic acid) and other water-soluble hydroxyacids to a crude oil can significantly reduce the amount of calcium and other metals and amines as well as reactive phosphorus species in the hydrocarbon when it is run through a desalter in a refinery [7].Toward this direction, Zhi, Bando, and Golberg have discovered that treatment of BNNTs in H2O2 introduces hydroxyl groups (single bondOH) to boron sites, while single bondNH to nitrogen sites [55]. These single bondOH groups were esterificated with perfluorobutyric acid (CF3CF2CF2COOH) and thioglycolic acid (HSCH2COOH), and employed for further chemical functionalization.Another unique advantage of using gold nanoparticles for the construction of electrochemical DNA biosensors is the development of amplification routes for the DNA sensing events. One of the earlier alternatives explored consisted of coupling the primary probe DNA recognition event with the use of a colloidal gold tag followed by label-free detection (i.e., using impedimetry). An illustrative example is the construction of an electrochemical DNA biosensor based on the assembly of highly conductive gold nanoparticles on the free terminal of hairpin-structured DNA probes. The bifunctional hairpin structure DNA probe with amino and thiol groups at the 3′- and 5′-ends, respectively, was immobilized on a gold electrode through the thiol group (Fig. 11.15). Then, thioglycolic acid (Thioglycolic acid  ) was grafted on the 3′-ends of hairpin DNA probes via the carboxylic-amino condensation reaction, and the gold nanoparticles tags were further attached on the free terminal of probe DNA through self-assembling with the SH of the modified Thioglycolic acid  . Thus a highly conductive biointerface with a significantly low electrochemical impedance background response in was constructed. Upon hybridization with complementary DNA the stem-loop portion of the hairpin DNA probe was converted into a rigid, linear double helix, which driven the gold nanoparticles tag far away from the electrode. Thus a significant increase in impedance occurred. The biosensor showed a wide dynamic detection range from 1.0×10-17 to 1.0×10-11 M, and a LOD of 1.7×10-18 M. In addition, it exhibited good selectivity, stability, and regeneration ability.Thioglycolic acid and its salts may be used in: Hair products: general use, max concentration allowed 8% (pH 7 to 9.5) professional use, max concentration allowed 11% (pH 7 to 9.5) Depilatories, max concentration allowed 5% (pH 7 to 12.7) Hair rinse-off products, max concentration allowed 2% (pH up to 9.5) Thus, the use of thioglycolic acid and thioglycolates in hair products is in accordance with the new European cosmetics legislation, but the application of these products to eyelashes has been prohibited since 11 July 2013.In order to ensure the legal compliance of these products, the applicant submitted a dossier for the safety assessment of thioglycolic acid and thioglycolates in cosmetic products used on eyelashes. It has been reported that eyelash-waving products based on thioglycolic acid derivatives are applied by professionals and during application a direct contact to the skin or eyes is avoided with the help of a sticking eyelash roll. Original studies on chemical characterisation, physico-chemical properties and toxicological endpoints of thioglycolic acid and its salts were not included in the submitted dossier. The submitted literature, as well as additional literature searched by the SCCS were used for the safety evaluation of thioglycolic acid and its salts in this Opinion. According to information submitted by the industry (ICADA 2012) the stability of thioglycolic acid in a gel preparation, containing circa 8.8% (range 8.7% to 8.9%) thioglycolic acid, over seven months at alternating temperatures (20°C / 40°C) in different bottles was evaluated.In the polyolefin bottle, the content of the active ingredient declined to 82.8% of the initial value. In the glass bottle the thioglycolic acid was able to resist the thermal stress (the final measured content was 97.8% of the t0-value). When the original product was stored at room temperature over one year, the content of the active ingredient declined to 94.9% of the initial value. Thus, this marketed product appeared to be stable with respect to thioglycolic acid content when stored in a glass bottle.Thioglycolic acid and its ammonium and sodium salts are toxic by oral administration. When expressed as thioglycolate anion, whatever the salt is, the LD50's of the salts were in the range of the thioglycolic acid LD50 in rats.In an acute oral toxicity study performed according to the OECD guideline # 401, 5 groups of 5 Sprague-Dawley rats per sex were dosed with 0, 40, 64, 80 and 200 mg/kg bw thioglycolic acid (purity 99%). Animals were observed for 14 days following the exposure for mortality and clinical signs. Mortality occurred at dose levels equal to and exceeding 64 mg/kg bw. Behavioural abnormalities (piloerection, lethargy, ptosis, prostration) were observed in all treated rats. The LD50 of thioglycolic acid was 73 mg/kg bw.The acute oral toxicity of ammonium and sodium thioglycolates was tested in male and female rats according to the Acute Toxic Class Method (OECD guideline # 423). The LD50 of the 71% aqueous solution of ammonium salt was between 50 and 200 mg/kg bw (or between 35 and 142 mg/kg bw when expressed as active ingredient) in rats. Sodium thioglycolate was tested pure (>98%) or as a 46% aqueous solution in Wistar rats, the LD50's were between 50 and 200 or 200 and 500 mg/kg bw (Sanders, 2000), respectively.Another study performed with ammonium thioglycolate according to the OECD guideline #401 lead to an acute LD50 between 25 and 200 mg a.i./kg bw in Wistar rats.Thioglycolic acid was applied as a single occlusive patch test on the abdominal skin of rabbits. Skin reactions were observed and recorded at various time intervals up to 7 hours or until a chemical burn was observed. At the end of the exposure period, the skin area was washed with soap and water. Thioglycolic acid application resulted in necrosis within 5 minutes. This was accompanied by hyperemia and edema.Patch tests with thioglycolic acid (apparently not neutralized) at concentrations (up to 11%) described as typical of hair waving solutions were carried out with duration from 1 hour through 96 hours on the unabraded skin of 294 and the abraded skin of 63 volunteers. In the study, the data from which were not presented fully in this paper, thioglycolic acid was found to cause irritation to the skin at 2.8% or higher, being most irritating to abraded skin.Tests using 4.6% aqueous thioglycolic acid caused irritation to the skin of volunteers after 4-6 hours.Thioglycolic Acid and it salts and esters modify hair fibers to facilitate changes to the structure of the fibers, such as with permanent waves or with hair straightening. They are also used to chemically break down hair fibers so that unwanted hair can be removed by simply wiping it from the skin.Based on Fenton reaction without adding nanomaterials, a simple colorimetric sensor for detecting thioglycolic acid (Thioglycolic acid  ) was developed. By reducing Fe³⁺ ions to Fe²⁺ ions, Thioglycolic acid   efficiently stimulates Fenton reaction through accelerating Fe³⁺/Fe²⁺ redox cycle. Owing to this, the accelerated decomposition of H2O2 generates more [rad]OH radicals, which cause a significant blue change in the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). Compared with Fe³⁺/H2O2/TMB system, this sensor can be operated over a wider pH range from 4.0 to 8.0. The calibration curve of Thioglycolic acid   is achieved in the concentration range of 0.046-7.37 μg mL⁻¹ under optimized conditions, and the detection limit of Thioglycolic acid   is 0.036 μg mL⁻¹ (S/N = 3). This sensor has been successfully applied to the detection of Thioglycolic acid   in cold wave lotion with recovery rates between 99.1 and 101.6%, which has broad application prospects in cosmetic analysis and environmental monitoring.
 
Thioglycolic acid appears as a colorless liquid with an unpleasant odor. Density 1.325 g / cm3. Used to make permanent wave solutions and depilatories. Corrosive to metals and tissue.

Molecular Weight of Thioglycolic acid:    92.12 g/mol     
XLogP3 of Thioglycolic acid:    0.1     
Hydrogen Bond Donor Count of Thioglycolic acid:    2     
Hydrogen Bond Acceptor Count of Thioglycolic acid:    3     
Rotatable Bond Count of Thioglycolic acid:    1     
Exact Mass of Thioglycolic acid:    91.993201 g/mol     
Monoisotopic Mass of Thioglycolic acid:    91.993201 g/mol     
Topological Polar Surface Area of Thioglycolic acid:    38.3 Ų     
Heavy Atom Count of Thioglycolic acid:    5     
Formal Charge of Thioglycolic acid:    0     
Complexity of Thioglycolic acid:    42.9     
Isotope Atom Count of Thioglycolic acid:    0     
Defined Atom Stereocenter Count of Thioglycolic acid:    0     
Undefined Atom Stereocenter Count of Thioglycolic acid:    0     
Defined Bond Stereocenter Count of Thioglycolic acid:    0     
Undefined Bond Stereocenter Count of Thioglycolic acid:    0     
Covalently-Bonded Unit Count of Thioglycolic acid:    1     
Compound  of Thioglycolic acid Is Canonicalized?:    Yes