Properties and Applications of Didecyl Dimethyl Ammonium Chloride (DDAC)

Didecyl dimethyl ammonium chloride (DDAC) is a quaternary ammonium compound (QAC) widely used as a broad-spectrum biocide, disinfectant, and cationic surfactant. It exhibits h3 antimicrobial activity against bacteria (both gram-positive and gram-negative), fungi, and enveloped viruses.

Key Properties

Property Details

Chemical Name Didecyl dimethyl ammonium chloride

CAS Number 7173-51-5

Molecular Formula C₂₂H₄₈N·Cl

Molecular Weight ~362.08 g/mol

Appearance Typically a liquid formulation (various concentrations available, e.g., 50%, 80%)

Solubility Soluble in water; functions as a cationic surfactant

DDAC is a high-foaming surfactant, which is an important property to consider in applications where foam control is critical.

Primary Applications

DDAC is a versatile compound used across multiple industries, primarily for its biocidal properties.

Application Area Specific Uses

Disinfection & Sanitization - Healthcare & Public Spaces: Disinfectant sprays, wipes, and cleaners.

- Food Industry: Sanitizer for food contact surfaces, equipment, and packing facilities.

- Institutional & Household: General-purpose disinfectant and sanitizer for various surfaces.

Industrial Water Treatment - Cooling Towers & Oilfield: Biocide and algicide for water treatment systems to control microbial growth.

- Swimming Pools: Algaecide and sanitizer.

Agriculture & Wood Preservation - Pesticide Adjuvant: Used to boost the performance of pesticides and herbicides.

- Wood Treatment: Widely used as a wood preservative and mildew preventative.

Other Applications - Textile & Petrochemical: Surfactant, emulsifier, and processing aid.

- Cosmetics & Personal Care: Ingredient in certain household and personal care products, such as hair conditioners and hand sanitizers.

Regulatory & Safety Considerations

Regulatory Status:

Registered as an antimicrobial pesticide with the U.S. EPA.

Approved as a biocidal active substance in the EU for various product types (e.g., disinfectants, wood preservatives).

Maximum residue limits (MRLs) exist for DDAC in food products within the EU, as residues can occur from its use in food processing and packaging facilities.

Toxicity & Sensitization:

Studies have shown DDAC to be toxic to aquatic life. For example, the 48-hour EC₅₀ for Daphnia magna is 0.094 mg/L, and the 96-hour LC₅₀ for rainbow trout is 1.16 mg/L.

Case reports and studies have identified DDAC as a potential skin sensitizer and irritant, with documented cases of allergic contact dermatitis. Inhalation exposure has also been associated with lung injury in animal studies.