Dodecyl Dimethyl Benzyl Ammonium Chloride (DDBAC) - CAS 139-07-1

Dodecyl Dimethyl Benzyl Ammonium Chloride (DDBAC) - Properties, Applications, and Safety

Dodecyl dimethyl benzyl ammonium chloride (DDBAC, CAS 139-07-1), also known as benzalkonium chloride C12 or benzyldodecyldimethylammonium chloride, is a representative quaternary ammonium compound (QAC) belonging to the class of cationic surfactants. It is a non-oxidizing biocide with broad-spectrum and highly effective bactericidal, fungicidal, and algicidal activity.

Chemical and Physical Properties

DDBAC has the molecular formula C₂₁H₃₈ClN and a molecular weight of approximately 339.99–340 g/mol. It typically appears as a colorless to pale yellow transparent liquid, though it can also be found as a white to light yellow crystalline powder. Key properties include:

• Melting Point: Approximately 31–32°C for liquid grades, or ~60°C for solid forms

• Boiling Point: 162.7°C at 101,325 Pa

• Density: 1.03 g/cm³ at 20°C

• pH (1% aqueous solution): 6.0–8.0

• Solubility: Highly soluble in water and organic solvents (866 g/L in organic solvents at 20°C)

• Hygroscopic: Absorbs moisture from air

• Stability: Chemically stable, heat-resistant, light-resistant, non-volatile

Mechanism of Action

As a cationic surfactant, DDBAC's positively charged quaternary ammonium head group electrostatically adsorbs to negatively charged microbial cell surfaces, disrupting membrane integrity and causing leakage of intracellular components. It functions as a non-oxidizing biocide, effectively controlling the growth of bacteria, fungi, algae, and biofilm formation, while also providing some dispersing, penetrating, and corrosion-inhibiting properties.

Applications

Disinfection and Sanitization: DDBAC is widely used as a disinfectant and antiseptic in healthcare, veterinary, and household applications. It is effective against bacteria, fungi, and some viruses, and is commonly employed as a medical instrument disinfectant.

Water Treatment: Used as a biocide and algicide in industrial cooling water systems, swimming pools, and wastewater treatment to control algae and slime formation.

Textile and Industrial Processing: Applied as an antistatic agent, disinfectant, and biocide in textile manufacturing and various industrial processes.

Agriculture: Used as a biocide for plant treatment and facility disinfection.

Household and Institutional Cleaning: Incorporated into surface disinfectants, sanitizers, and cleaning products.

Safety and Toxicology

DDBAC is classified as a hazardous substance. It is harmful if swallowed, in contact with skin, or if inhaled (H302+H312+H332). It causes severe skin burns and eye damage (H314) and is very toxic to aquatic life with long-lasting effects (H410). At high concentrations, it is irritating and corrosive to skin. Environmental studies have demonstrated that DDBAC can disrupt gut microbiota, phospholipids, and calcium signaling in non-target organisms such as honeybees at environmentally relevant levels, and has inhibitory effects on microalgae in wastewater.

Storage and Handling

Store in tightly sealed, corrosion-resistant containers in a cool, dry, well-ventilated area, away from strong oxidizers. Use appropriate personal protective equipment (gloves, safety goggles) when handling. Avoid release into the environment. In case of skin or eye contact, rinse thoroughly with water and seek medical attention if irritation persists.

Conclusion

Dodecyl dimethyl benzyl ammonium chloride (DDBAC, CAS 139-07-1) is a versatile cationic surfactant and broad-spectrum antimicrobial agent widely used in disinfectants, water treatment, and industrial applications. Its strong bactericidal and algicidal properties, combined with good water solubility and stability, make it an effective biocide across multiple sectors. However, its toxicity to aquatic organisms and potential health hazards require careful handling and adherence to safety regulations.