THIOGLYCOLIC ACID (MERCAPTOACETIC ACID)

THIOGLYCOLIC ACID

PRODUCT IDENTIFICATION

CAS NO.

68-11-1

THIOGLYCOLIC ACID

EINECS NO. 200-677-4

FORMULA

HSCH₂COOH

MOL WT.

92.12

H.S. CODE

2930.90

TOXICITY

Oral, rat LD50 : 114 mg/kg

SYNONYMS 2-Mercaptoacetic acid Thiovanic acid

2-Thioglycolic acid alpha-Mercaptoacetic acid Mercaptoessigsä ure (German) á cido mercaptoacé tico (Spanish) Acide mercaptoacé tique (French)

SMILES

chloroacetic acid

CLASSIFICATION

THIOGLYCOLATE /

PHYSICAL AND CHEMICAL PROPERTIES

PHYSICAL STATE Colorless liquid

MELTING POINT

-16.5 C

BOILING POINT 96 C

SPECIFIC GRAVITY 1.325

SOLUBILITY IN WATER

100 mg/ml

pH 1.6 (10% solution)

VISCOSITY 6.35 cps at 20 C

AUTOIGNITION

350 C

REFRACTIVE INDEX

1.503

NFPA RATINGS Health: 3 Flammability: 0 Reactivity: 2

FLASH POINT

112 C

STABILITY Stable under ordinary conditions

GENERAL DESCRIPTION & APPLICATIONS

Glycolic acid is the smallest alpha-hydroxy acid (AHA) which has a hydroxyl group on the carbon atom next to the acid group. If the hydroxy group is on the second carbon next to the acid group, it is called beta-hydroxy acid. Glycolic acid is a low mole weight compound but has dual functionality of alcohol and acid. Because of its small molecular weight and size, it has a better capability to penetrate skin. AHA is used extensively in cosmetics. It is known that it diminishes the lines on the skin and make skins look young by acting as a humectant to absorb moisture in air and by exfoliating action to break the bonds between dead skin cells, Pure glycolic acid is a white crystals decomposes about 78 C very soluble in water, alcohols, acetone, acetates slightly soluble in ethyl ether sparingly soluble in hydrocarbon solvents polymerization occurs above 50 C. Commercially, it is available in crystal form as well as in aqueous solutions of various concentrations, usually 70 percent or less. Activating both the hydroxyl and carboxylic acid group, glycolic acid has the property to form metal complexes and can be used in cleaning applications and hard water dissolution. Aqueous solution grade is mainly used fro this cleaning application. Glycolic acid is an useful intermediate in organic synthesis including oxidation/reduction, esterification and formation of oligomers as well as long chain polymerization. Glycolic acid is naturally found in sugar beets, cane sugar, and unripe grapes. It is known that it diminishes the lines on the skin and make skins look young. Synthetic glycolic acid and its derivatives are used commercially in leather tanning and textile dyeing as a flavouring agent and preservative in food processing, water treatment industries pH control and chemical intermediates as well as in household, industrial, electronics cleaning applications and cosmetics. They are also used in emulsion polymers, solvents and ink and paint additive to improve flow properties and impart gloss.

'Thio' is a chemical prefix indicates the replacement of an oxygen in an acid radical by sulfur with a negative valence of 2 meaning 'sulfur' derived from the Greek theion. In substitutive nomenclature their names are formed by adding '-thiol' as a suffix to the name of the parent compound. When -SH is not the principal group, the prefix 'mercapto-' is placed before the name of the parent compound to denote an unsubstituted -SH group. Thioglycolic acid, a simple sulfur group- chained carboxylic acid, is a clear liquid melts at -16. C, boils at 96 C soluble in water. It is an useful chemical intermediate in the chemical reactions such as addition, elimination and cyclization. Sulfur group will react with bases, acids, ketoness and organic halogen compounds, whereas the carboxylic group will preferentially react In the presence of alcohols or amines. The applications of thioglycolic acid and its derivatives are wide in the fields of

Main materials for the synthesis of PVC stabilizers.
Down-hole acidizing
Corrosion inhibition in the oil field industry.
Manufacturing of pharmaceuticals, agrochemicals and dyes
Hair care products (waving, hair removal and hair straightening)
Shrink-resistant treatment of wool
Fabric dying
Leather processing.

The first chemical contrast of thiols and sulfides with alcohols and ethers is acidity which is important in organic reactions. Thiols are stronger acids than relevant alcohols and phenols. Thiolate conjugate bases are easily formed, and are excellent nucleophiles in SN2 reactions of alkyl halides and tosylates. The nucleophilicity of sulfur is much greater than that of oxygen, resulting in a number of useful electrophilic substitution reaction that are rare by oxygen. For example, sulfides form (with alkyl halides) ternary sulfonium salts, in the same alkylattion of tert-amines quaternary ammonium salts, whereas ternary oxonium salts are prepared only under extream conditions. Without exception, sulfoxides, sulfinate salts and sulfite anion also alkylate on sulfur, despite of the partial negative formal charge on oxygen and partial positive charge on sulfur. The second character is the oxidation states of sulfur. Oxygen has only two oxidation states, whereas sulfur covers from –2 to +6 as follows:

-2: Hydrogen Sulfide (H₂S), sulfides, sulfonium ions
-1: disulfides
0: S elemental, sulfoxides, sulfenic acids
+2: sulfones, sulfinic acids
+4: sulfonic acids, sulfite esters
+6: sulfate esters

One more sulfur compound's contrast with oxygen analog is in oxidation chemistry. Oxidation of sulfur compounds changes the oxidation state of sulfur rather than carbon, whereas, oxidation of alcohols to aldehydes and ketones changes the oxidation state of carbon not oxygen. Thiols is oxidized to S-S single bond (disufide) which is stronger than O–O bond in peroxide. Disufide forms sulfenyl chlorides (with chlorine in mild condition) or sulfonic acids under harder condition. Oxidation of sulfides with hydrogen peroxide (or peracids) yields sulfoxides and then to sulfones. A certain sulfoxide compound such as dimethyl sulfoxide can be used as an effective oxygen source in the oxidation reaction of primary and secondary alcohols to aldehydes and ketones. DMSO easily is reduced to dimethyl sulfide and water is taken up by the electrophile. oxidation procedure is very mild and tolerates a variety of other functional groups, including those having oxidizable nitrogen and sulfur atoms.

Thioglycolic acid, a simple sulfur group- chained carboxylic acid, is a clear liquid melts at -16. c, boils at 96 C soluble in water. It is an useful chemical intermediate in the chemical reactions such as addition, elimination and cyclization. Sulfur group will react with bases, acids, ketones and organic halogen compounds, whereas the carboxylic group will preferentially react In the presence of alcohols or amines. The applications of thioglycolic acid and its derivatives are wide in the fields of PVC stabilizers, down-hole acidizing, corrosion inhibition in the oil field industry, manufacturing of pharmaceuticals, agrochemicals and dyes, shrink-resistant treatment of wool, fabric dying, leather processing.

Thioglycolates are used in cosmetic hair-care products especially permanent waving products as they weaken the keratin structure by the opening of the cystine disulfide linkages. In addition to hair-waving application, they are used as depilating agents to remove unwanted body hair. The break-down of disulfide bonds in the cortex by thioglycolates either rearranges (permanent waving) or entirely destroys (depilating) hair structure. As an antioxidant application in cosmetics, thioglycolates protect the product itself not the skin against oxidative reactions promoted by ultraviolet radiation or oxygen.

SALES SPECIFICATION

96%

APPEARANCE

Clear liquid

ASSAY

96.0% max

EXCESS ACID

1.0% max

COLOR, APHA

15 max

IRON (Fe)

1ppm max

80%

APPEARANCE

Clear liquid

CONTENT

78.0 - 82.0

EXCESS ACID

1.0% max

COLOR, APHA

15 max

IRON (Fe)

1ppm max

TRANSPORTATION

PACKING 260kgs in Drum

HAZARD CLASS 8

UN NO. 1940

OTHER INFORMATION

Hazard Symbols: T, Risk Phrases: 23/24/25-34, Safety Phrases: 25-27-28-45

PRICES