Calcium Thioglycolate, Calcium Mercaptoacetate, 814-71-1

Calcium Thioglycolate, Calcium Mercaptoacetate, 814-71-1

Molecular Formula: C₄H₆CaO₄S₂
Molecular Weight: 222.3 g/mol
Chemical Name: Calcium Thioglycolate
CAS Number: 814-71-1

General Information and Description

Calcium Thioglycolate is the calcium salt of Thioglycolic Acid. It is a chemical compound widely recognized as the primary active ingredient in depilatory (hair removal) products within the cosmetic and dermatological industries. While the pure chemical is odorless, it produces a characteristic, unpleasant odor when used in formulations.

This odor is directly linked to its mechanism of action. Calcium Thioglycolate works by breaking the disulfide bonds (chemical bonds between sulfur atoms) found in the protein structure of hair (keratin). The cleavage of these bonds releases sulfur-containing compounds, which is the source of the typical "rotten egg" smell associated with hair removal creams.

It shares similar properties with Potassium Thioglycolate but is generally considered to have stronger, more potent effects.

Synonyms

• 814-71-1 (CAS Number)

• Calcium Mercaptoacetate

• Thioglycolic acid calcium salt

• Mercaptoacetic acid calcium derivative

• Calcium Bis(sulfanylacetate)

Production Method

Calcium Thioglycolate is produced through a controlled neutralization reaction between Calcium Hydroxide [Ca(OH)₂] and Thioglycolic Acid (HS-CH₂-COOH). The reaction yields the calcium thioglycolate salt and water.

Physical and Chemical Properties

• Physical Appearance: White to off-white crystalline powder.

• Odor: Odorless in its pure, dry state.

• pH Value: Its aqueous solution is strongly alkaline, typically with a pH range of 11–12.

• Thermal Stability:

  • Begins to lose water of crystallization above 95°C (203°F).

  • Decomposes at temperatures exceeding 220°C (428°F).

• Purity and Concentration: The active ingredient is typically available at a high purity of 99.4% . This pure substance contains the equivalent of approximately 49.7% Thioglycolic Acid.

Applications and Uses

The primary application of Calcium Thioglycolate is in cosmetic and dermatological products. Its function relies on its ability to reduce and cleave the disulfide bonds in the keratin protein.

1. Depilatory Creams (Hair Removal Creams):

   • This is the most common use. It chemically weakens the hair shaft above the skin's surface. The hair structure is broken down into a gelatinous mass that can be easily wiped away with a spatula or damp cloth, without affecting the hair follicle or root.

   • In depilatory cream formulations, the concentration of Calcium Thioglycolate is typically 5–6% . These products often include other ingredients like Lidocaine (a local anesthetic) to minimize potential skin irritation or burning sensations during use.

2. Hair Shaping Products (Permanent Waves and Straighteners):

   • Thioglycolic acid and its salts are the key ingredients in products designed for permanent waving (perms) and chemical hair straightening.

   • Mechanism of Action: The thioglycolate solution is first applied to break the disulfide bonds in the hair, making it soft and pliable so it can take on a new shape (around curlers or straightened). After the desired shape is achieved, a neutralizing solution, often containing Hydrogen Peroxide (H₂O₂), is applied. This oxidizer reforms the disulfide bonds, locking the hair permanently into its new configuration.

3. Other Applications:

   • Acne Treatment: Due to its keratolytic properties (ability to soften and break down keratin), it can be found in creams and lotions for treating acne. It helps to dissolve the plugs of keratinized skin cells (comedones) that block pores.

   • Dermocosmetic Products: Used in the formulation of specialized, often gentler, depilatory creams intended for sensitive areas, such as the face.