Thioglycolic acid

• Thioglycolic acid
• TGA
• Sulfanylessigsäure
• THIOGLYCOLIC ACID (INCI)

Colorless liquid with an unpleasant odor

Liquid

1.33 g · cm -3

-17 ° C.

105 ° C (19 hPa)

10 Pa ( 20 ° C)

3.68 (25 ° C)

Miscible with water, ethanol, chloroform, toluene, and diethyl ether

1.5080 (20 ° C)

Risk

73 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search available

Mercaptoacetic acid (other name: thioglycolic acid ) is a colorless, viscous liquid and belongs to the group of thiols, their salts hot thioglycolates. It is chemically related to the glycolic acid.

Synthesis

The synthesis is carried out chloroacetic acid and sodium hydrogen sulfide by nucleophilic substitution.

Use

It is used in depilatory products and salon products for perms since about 1940. These contain about 1 to 11% mercaptoacetic acid as the ammonium salt ( ammonium thioglycolate ):

The use of permanent waves is based on the discovered by Leonor Michaelis solubility of keratin - from which hair are made - in thioglycolic acid. This disulfide bridges are separated between two cysteine ​​units of keratin by reduction.

If necessary, you can also find Kaliumthioglykolat in depilatory products. In addition, it is used in leather processing and in the production of stabilizers for PVC. Furthermore, can be detected with their iron ions by an intense red color. The reaction of mercaptoacetic acid with cyclic imines leads to bicyclic lactams.

Safety

Upon heating, mercaptoacetic acid decomposed under formation of toxic vapors ( hydrogen sulfide and sulfur oxides).