Octadecyltrimethylammonium Chloride (STAC) CAS 112-03-8

Octadecyltrimethylammonium Chloride (Steartrimonium Chloride) – Cationic Surfactant for Conditioning and Antistatic Applications

Basic Information

• CAS Number: 112-03-8

• Molecular Formula: C₂₁H₄₆ClN

• Molecular Weight: ~348.0 g/mol

• Synonyms: Steartrimonium chloride, Stearyltrimethylammonium chloride, Cetyltrimethylammonium chloride (C18 analog)

• Appearance: White to off-white powder or flakes, forming clear solutions in warm water

• Solubility: Soluble in warm water and alcohols; practically insoluble in non‑polar solvents

• Storage: Store in a cool, dry place, in tightly sealed containers, protected from moisture and light

Overview
Octadecyltrimethylammonium chloride (commonly known as Steartrimonium chloride or STAC) is a cationic surfactant with a long hydrophobic octadecyl (C18) chain and a positively charged trimethylammonium head group. This structure provides excellent conditioning, antistatic, and emulsifying properties, making it a valuable ingredient in hair care, textile processing, and cosmetic formulations. It is particularly valued for its ability to reduce static electricity, improve softness, and enhance product texture.

Applications

• Hair care: Used in conditioners, hair masks, and leave‑in treatments to improve wet and dry combability, reduce static, and impart smoothness and shine.

• Cosmetics: Functions as an emulsifier and conditioning agent in creams, lotions, and skin care products.

• Textile industry: Applied as a softener and antistatic agent for fabrics, improving hand feel and reducing static cling.

• Leather processing: Used as a softening and conditioning agent in leather treatment.

• Industrial: Employed as a flotation agent, phase transfer catalyst, and in water treatment applications.

Key Benefits

• Excellent conditioning and softening properties.

• Effective antistatic agent – reduces static electricity.

• Good emulsification and dispersing capabilities.

• Compatible with nonionic and cationic surfactants (avoid anionic surfactants).

• Stable over a wide pH range.

• Cost‑effective and widely available.

Safety and Handling

• May cause mild skin and eye irritation at high concentrations; use appropriate personal protective equipment (gloves, safety goggles) when handling.

• Incompatible with anionic surfactants – forms precipitates.

• Avoid contact with strong oxidizers and acids.

• Store in a cool, dry place, away from direct sunlight.

• Shelf life: typically 24 months under recommended storage conditions.

Quality Assurance
Each batch is tested for active content, pH, and performance properties to ensure consistent quality.