What is Thioglycolic Acid (TGA)?
Thioglycolic Acid (TGA), also known as mercaptoacetic acid, is an organic compound with the chemical formula HSCH₂COOH. It is a colorless liquid with a strong, unpleasant odor, widely used in cosmetics, industrial applications, and research.
What are the main uses of Thioglycolic Acid?
TGA is commonly used in:
- Hair care products (e.g., permanent wave solutions and depilatory creams);
- Industrial applications (e.g., PVC stabilizer, rust remover);
- Scientific research (e.g., bacterial culture media).
What is the chemical formula of Thioglycolic Acid?
The chemical formula of TGA is HSCH₂COOH.
What is the molecular weight of Thioglycolic Acid?
The molecular weight of TGA is 92.12 g/mol.
What are the physical properties of Thioglycolic Acid?
TGA is a colorless liquid with a strong, rotten egg-like odor. It has a density of 1.32 g/cm³, a boiling point of 209°C, a melting point of 10°C, and is miscible with water and polar solvents like methanol and ethanol.
What is the pH range for Thioglycolic Acid in hair care products?
In permanent wave solutions, TGA is typically used at a pH range of 7 to 9.5 to balance effectiveness and hair safety.
What is the mechanism of action of Thioglycolic Acid in hair treatments?
TGA breaks the disulfide bonds (-S-S-) in hair keratin, allowing the hair to be reshaped. A neutralizing agent, like hydrogen peroxide, then reforms the bonds to set the new shape.
What are the safety concerns associated with Thioglycolic Acid?
TGA is corrosive and may cause skin/eye irritation or allergic reactions. Protective equipment is recommended during handling.
What are the alternatives to Thioglycolic Acid in hair care?
Alternatives include ammonium thioglycolate, cysteine, and sulfites, though TGA is favored for its efficacy.
What is the difference between Thioglycolic Acid and Thioglycolate salts?
Thioglycolate salts (e.g., ammonium thioglycolate) are derivatives of TGA, often used at higher pH levels to reduce hair damage.
What is the shelf life of Thioglycolic Acid?
TGA remains stable for several years when stored in a sealed container in a cool, dry, dark place.
What is the odor of Thioglycolic Acid, and how is it managed?
TGA has a strong, unpleasant rotten egg-like smell, often masked with fragrances in products.
What are the environmental impacts of Thioglycolic Acid?
TGA is biodegradable and does not persist in the environment, but it requires proper disposal as hazardous waste.
What is the production method of Thioglycolic Acid?
TGA is typically made by reacting chloroacetic acid with sodium hydrosulfide or via the Bunte salt method.
What is the role of Thioglycolic Acid in depilatory creams?
TGA weakens hair by breaking disulfide bonds, allowing it to be easily removed.
What are the potential side effects of Thioglycolic Acid on skin?
Side effects include irritation, redness, itching, or allergic reactions. Avoid contact with eyes and mucous membranes.
What is the concentration of Thioglycolic Acid in permanent wave solutions?
Concentrations typically range from 5% to 10%, depending on hair type and desired effect.
What are the long-term effects of using Thioglycolic Acid on hair?
Overuse can make hair dry, brittle, or prone to breakage, requiring regular conditioning.
What are the storage recommendations for Thioglycolic Acid?
Store in a cool, dry, dark place, away from oxidizing agents and metals, in a tightly sealed container.
What is the role of Thioglycolic Acid in bacterial culture media?
TGA creates a reducing environment in thioglycolate media, supporting the growth of anaerobic bacteria.
What is the CAS Number of TGA?
The CAS Number of Thioglycolic Acid is 68-11-1.
What are the safety measures for handling TGA?
When handling TGA, wear appropriate protective equipment, including gloves, goggles, and a face mask. Avoid skin and eye contact, and work in a well-ventilated area.
