Thioglycolic acid

Description

 

Thioglycolic Acid (TGA)

Thioglycolic Acid (TGA), also known as mercaptoacetic acid, is a colorless to pale yellow liquid with a strong, characteristic odor. It is a highly versatile compound featuring both a thiol (-SH) and a carboxylic acid (-COOH) functional group, giving it strong reducing properties and wide industrial utility.

Chemical Properties

• Molecular Formula: C₂H₄O₂S
• Molar Mass: 92.12 g/mol
• CAS Number: 68-11-1
• Solubility: Miscible with water, alcohols, and most organic solvents
• Boiling Point: ~218°C

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Applications

1. Construction & Concrete Additives
   Thioglycolic acid plays an important indirect role in the concrete industry, particularly in the production of polycarboxylate ether (PCE) superplasticizers—advanced admixtures used to enhance the flowability and strength of concrete. TGA is used as a chain transfer agent during the polymerization process, helping control the molecular weight and structure of PCEs. This control is critical to improving the workability and water reduction performance of modern concrete formulations.
2. Cosmetics & Personal Care
   Widely used in depilatory creams and hair treatments, TGA breaks disulfide bonds in keratin, enabling hair reshaping or removal.
3. Metal Treatment & Electroplating
   Used as a complexing agent and corrosion inhibitor in metal cleaning and electroplating baths, especially for copper and silver.
4. Photographic Industry
   Serves as a stabilizer and processing aid in developing solutions.
5. Polymer Chemistry
   Functions as a chain transfer agent in radical polymerizations to control polymer size and branching, particularly in PVC and acrylic resins.
6. Oil & Gas
   Used in scale removal agents and corrosion control in oilfield applications.

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Advantages

• Strong reducing agent
• Dual functionality (thiol and carboxylic groups)
• High reactivity
• Plays a critical role in advanced polymer synthesis (e.g., for concrete additives)

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Safety and Handling

Thioglycolic acid is corrosive and toxic, requiring careful handling. It can cause severe skin and eye burns and should not be inhaled. Appropriate personal protective equipment (PPE) such as gloves, goggles, and chemical-resistant clothing must be used. Industrial storage should be well-ventilated, clearly labeled, and compliant with GHS hazard communication standards.