Ammonium thioglycolate Property

Melting point:

139-139.5 °C

Boiling point:

115℃[at 101 325 Pa]

Density 

1.22

vapor pressure 

0.001Pa at 25℃

form 

Solution

Specific Gravity

1.245 (25℃)

color 

Clear colorless

Odor

strong skunk-like odor

Water Solubility 

Miscible

InChI

InChI=1S/C2H4O2S.H3N/c3-2(4)1-5;/h5H,1H2,(H,3,4);1H3

InChIKey

JYAVWXRMOOCSOD-UHFFFAOYSA-N

SMILES

C([O-])(=O)CS.[NH4+]

LogP

-2.99 at 20℃

CAS DataBase Reference

5421-46-5(CAS DataBase Reference)

EPA Substance Registry System

Acetic acid, 2-mercapto-, ammonium salt (1:1) (5421-46-5)

Safety

Hazard Codes 

T

Risk Statements 

25-43

Safety Statements 

36/37-45-37-24

RIDADR 

2810

WGK Germany 

1

RTECS 

AI7525000

HazardClass 

6.1(b)

PackingGroup 

III

HS Code 

29309090

Hazardous Substances Data

5421-46-5(Hazardous Substances Data)

Toxicity

LD50 ipr-rat: 165 mg/kg JPETAB 97,349,49

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H290May be corrosive to metals

H301Toxic if swalloed

H317May cause an allergic skin reaction

Precautionary statements

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

Ammonium thioglycolate Chemical Properties,Usage,Production

Description

Ammonium thioglycolate, also known as perm salt, is the chemical compound with the formula HSCH₂CO₂NH₄. Being the salt of a weak acid and weak base, ammonium thioglycolic acid exists in solution as an equilibrium mixture of the salt itself as well as the free carboxylic acid thioglycolic acid (HSCH₂CO₂H) and ammonia : HSCH₂COO^- + NH₄⁺ ? HSCH₂COOH + NH₃.

Chemical Properties

Clear colorless solution with characteristic odor

Uses

acts as a reducing agent in permanent-waving formulations for hair treatment and in shrink-resistant treatment of wool.

Uses

Ammonium thioglycolate is contained in permanent waves solutions and causes contact dermatitis in hairdressers.

Uses

Solutions of various strengths are used for hair waving and for hair removal.

Definition

ChEBI: Ammonium thioglycolate is an organic ammonium salt having thioglycolate(1-) as the counterion. Also known as perm salt, it has use in perming hair. It has a role as a reducing agent and an allergen. It contains a thioglycolate(1-).

General Description

Colorless to faint pink liquid with a repulsive, skunk-like odor.

Air & Water Reactions

Water soluble.

Reactivity Profile

Ammonium thioglycolate may be sensitive to heat. Ammonium thioglycolate is incompatible with acids.

Health Hazard

Exposure to this compound may cause sensitivity dermatitis of scalp or hands, with edema, erythema, subcutaneous lesions, burning of skin, papular rash and itching. It may also cause hypoglycemia. Other symptoms include central nervous system depression, convulsions and dyspnea.

Fire Hazard

Flash point data for Ammonium thioglycolate are not available. Ammonium thioglycolate is combustible.

Flammability and Explosibility

Not classified

Contact allergens

This substance is contained in “basic” permanent waves solutions and causes contact dermatitis in hairdressers.

Safety Profile

Poison by intravenous and intraperitoneal routes. An allergen; can cause contact dermatitis. Emits hydrogen sulfide. See also SULFIDES. When heated to decomposition it emits very toxic NOx, SOx, and NH3.

Chemical concepts related to perms

When discussing the chemistry of perms, one should consider two chemical facts. First is the thiol-disulfide equilibrium:
RSH + R'SSR' ? R'SH + RSSR'
where R and R' are organic substituents such as methyl (-CH3), ethyl (-C₂H₅), or -CH₂COO^-.
The thiol-disulfide exchange reaction is accelerated by bases such as ammonia, because the base generates some thiolate anion (RS^- ), which attacks the disulfide. Thus the ammonia plays multiple roles (and more, see below) in this application.
The second chemical fact is that polar molecules are less volatile than nonpolar ones. So the glycolate substituent makes the thiol nonvolatile and hence non-odorous. An added advantage is that the glycolate confers some solubility in water. One could almost certainly use HSCH₃ and ammonia to give a perm, but there would be serious olfactory consequences.

The actual chemistry of perms

A solution containing ammonium thioglycolate contains a lot of free ammonia, which swells hair, rendering it permeable. The thioglycolic acid in the perm solution reduces the disulfide cystine bonds in the cortex of the hair. In a sense, the thioglycolate removes crosslinks. After washing, the hair is treated with a mild solution of hydrogen peroxide, which oxidizes the cysteines back to cystine. These new chemical bonds impart the structural rigidity necessary for a successful perm. The rigidification process is akin to the vulcanization of rubber, where commonly polysulfide linkages are used to crosslink the polymer chains. However, not as many disulfide bonds are reformed as there were before the permanent. As a result, the hair is weaker than before the permanent was applied and repeated applications over the same spot may eventually cause strand breakage.