Sodium PCA CAS 28874-51-3
What is Sodium Pyrrolidone Carboxylic Acid?
Sodium Pyrrolidone Carboxylic Acid (PCA-Na) is an amino acid derivative, a naturally occurring substance in the skin. It is soluble in water and ethanol but insoluble in oil. It is an important component of the body's natural moisturizing factor, highly hygroscopic, non-toxic, non-irritating, and stable, making it an ideal natural cosmetic and health product for modern skin and hair care. Sodium pyrrolidone carboxylate (PCA-Na) has strong hygroscopic properties and can absorb moisture from the air. In cosmetics, it is used as a moisturizer, and its moisturizing ability is stronger than traditional moisturizers such as glycerin, propylene glycol, and sorbitol. In addition to its powerful moisturizing effect, it also has a broad-spectrum penetration-enhancing effect. At low concentrations, it selectively distributes into keratinocytes; at high concentrations, it affects the fluidity of the stratum corneum and simultaneously promotes the distribution of active ingredients within the stratum corneum. Sodium PCA is non-irritating to the skin and eyes, does not clog pores, and has high safety, making it an excellent cosmetic moisturizer.
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Characteristics of Sodium Pyrrolidone Carboxylic Acid
1. Moisturizing and Water Retention
Hygroscopicity: Its moisture absorption capacity is up to 2 times that of polyethylene glycol and 6 times that of sorbitol, capable of absorbing and locking in several times its own weight in water.
Moisturizing Properties: Replenishing sodium PCA in the stratum corneum helps strengthen the natural barrier against moisture loss and enhances the skin's self-moisturizing ability. It has low viscosity, does not produce the sticky feeling of glycerin-based moisturizers, and is refreshing and easily absorbed.
2. Improves Skin Texture
Enhances Skin Elasticity: By increasing the moisture content of the stratum corneum, it makes skin softer and more elastic. When used in conjunction with other moisturizing ingredients such as hyaluronic acid, it can work synergistically to improve overall moisturizing effects.
3. Brightens Skin Tone
Inhibits Melanin Production: By inhibiting tyrosine oxidase activity, it reduces melanin deposition, helping to maintain a fair complexion. Suitable for whitening skincare products.
4. Softens Cuticles
It can act as a cuticle softener, improving rough skin. It has a certain auxiliary care effect on abnormal keratinization problems such as psoriasis and strengthens the stratum corneum structure, improving the skin's moisturizing and protective abilities.
5. Hair Care Effects
Used in shampoos and conditioners, it can increase hair moisture, shine, and elasticity, reducing frizz and static electricity caused by dryness.
6. Safety
Gentle: Non-irritating to skin and mucous membranes, with high safety, suitable for sensitive skin.
Natural Source: As an inherent component of the skin, it has good biocompatibility.
7. Antioxidant and Anti-aging
Helps fight free radicals, delays skin aging, and assists in skin repair and revitalization.
Applications of Sodium Pyrrolidone Carboxylic Acid
I.Personal Care and Cosmetics (Core Applications)
As a powerful moisturizer and skin conditioner
Applied products: face creams, lotions, serums, masks, toners, etc.
Hair Care Products
As a moisturizer, antistatic agent, and conditioner
Applied products: shampoos, conditioners, hair masks, hair sprays, etc. Replenishes moisture to the hair shaft, increases shine, smoothness, and elasticity, effectively reduces frizz, flyaways, and static caused by dryness, and makes hair easier to comb.
Oral Care Products
As a humectant and moisturizer
Applied products: toothpaste, mouthwash, etc. Provides a long-lasting moisturizing sensation, improves the texture of pastes, and helps maintain the comfort of the oral mucosa.
II. Pharmaceuticals and Health
Utilizing its high biocompatibility, physiological activity, and ability to aid penetration. As an excipient in topical medications such as ointments, creams, and gels.
Applications: Used in adjunctive care products for skin problems such as psoriasis and xerosis. It effectively softens the stratum corneum and regulates epidermal moisture, helping to relieve symptoms such as scaling and dryness.
III. Industrial Applications
Utilizing its strong hygroscopicity, antistatic properties, softening ability, and compatibility, it is used as a dyeing auxiliary, softener, and antistatic agent.
As a leather fatliquoring agent or softener, it penetrates into the leather, giving the finished leather excellent softness, fullness, and certain antistatic properties.
As a wetting agent and dispersant. It improves the dispersion stability of pigments in the system and enhances the flowability and coating uniformity of coatings.
The synthesis of sodium pyrrolidone carboxylate mainly uses L-glutamic acid as a raw material, which undergoes intramolecular dehydration condensation to form PCA, followed by neutralization to form PCA-Na.
There are multiple routes to achieve the above synthesis process.
1. Biocatalytic Method
Glutamic acid is used as a raw material, and pyrrolidone carboxylic acid is obtained by catalytic condensation with alkalobacterium glycosides produced by microorganisms. Powdered alkalobacterium glycosides (0.2 g/L) and ZnCl2 (5 × 10⁻⁵ mol/L) are added to an aqueous solution of glutamate, and the reaction is carried out at 50℃ and pH 7.4 for 60 min, achieving a conversion rate of 95%.
2. Dry Pyrolysis
L-Sodium glutamate (melting point 195℃) can be thermally decomposed at 195~270℃ to obtain sodium L-pyrrolidone carboxylic acid (melting point 156~157℃). Heating at 220℃ for 1 h yields a clear melt, which, upon cooling, yields sodium L-pyrrolidone carboxylic acid, with a conversion rate of 99%. Passing its aqueous solution through an ion exchange resin yields L-pyrrolidone carboxylic acid. Recrystallization of the sodium glutamate pyrolysis product with water yields rhombic crystals containing three molecules of water of crystallization.
3. Wet pyrolysis
Heating an aqueous solution of L-glutamic acid under reflux overnight yields a pyrrolidone carboxylic acid solution (conversion rate 85-86%). Unconverted L-glutamic acid is removed using a cation exchange resin, or 1 part L-glutamic acid is dissolved in 3 parts water, heated to decompose and generate pyrrolidone carboxylic acid, which is then recrystallized from ethanol. Crude pyrrolidone carboxylic acid is also soluble in acetic acid at 80°C. After cooling and crystallization, it is washed with acetone-acetic acid and water, respectively, and then dried under vacuum at 40°C.