Buying DDAC: What Matters
DDAC (didecyl dimethyl ammonium chloride, CAS 7173-51-5) is a liquid cationic biocide supplied as an 80% solution. Buying it well means confirming the identity and active content, checking residual amine and pH, choosing the right form for your process, and respecting the regulatory and compatibility rules that apply to quaternary ammonium biocides.
For the chemistry and applications behind these points, see our main article on DDAC (CAS 7173-51-5).
Step 1: Confirm the Identity
DDAC is easily confused with other quaternary ammonium biocides, so start with identity:
| Substance | CAS | Distinguishing feature |
|---|---|---|
| DDAC | 7173-51-5 | Two C10 chains |
| BAC (benzalkonium chloride) | 8001-54-5 | One alkyl chain + benzyl group |
Confirm the CAS number and, if a blend is offered, its composition.
Step 2: Read the Specification
| Parameter | Why it matters | Typical value |
|---|---|---|
| Active matter | Defines dosing and cost per active unit | ≥ 80% |
| Appearance | Confirms a clean, light solution | Light yellow to white transparent liquid |
| Free amine and amine salt | Measures completeness of quaternisation; affects odour and compatibility | ≤ 2% |
| pH (1% solution) | Affects stability and performance | 4 – 8 |
The active content and the free-amine figure are the two most decision-relevant parameters: the first sets your dosing, the second reflects product quality.
Step 3: Match the Form to Your Process
- 80% solution. The standard bulk grade for formulators; diluted on site.
- Lower-strength solutions. For convenience or regulatory reasons.
- Blends. DDAC with BAC or other quats, or pre-formulated disinfectant/sanitiser concentrates.
Step 4: Respect the Rules
- Cationic compatibility. Do not combine DDAC with anionic surfactants or anionic polymers; they precipitate and deactivate each other.
- Regulatory fit. Biocides are regulated by use; confirm the grade and documentation are acceptable for your product type and market.
- Handling. The concentrate is irritant/corrosive and toxic to aquatic life; plan for PPE and containment.
Supplier Checklist
- Identity. CAS 7173-51-5 confirmed.
- Active content. 80% (or as specified), with a clear basis.
- Free amine / pH. Within specification.
- Form and packaging. Drum or IBC, suited to your dilution system.
- Documentation. SDS, per-batch COA and applicable biocide regulatory statements.
- Consistency. Batch history if colour or active content is critical.
Common Buying Mistakes
- Confusing DDAC with BAC. Different substances; confirm the CAS.
- Buying on active content alone. A high assay with a high free-amine level may underperform.
- Overlooking compatibility. Using DDAC in an anionic system wastes both products.
- Ignoring regulation. Biocide uses are regulated; the wrong grade or documentation blocks legal use.
- Poor storage. Keep containers sealed and away from anionics and oxidisers.
How PolyBlueChem Can Help
PolyBlueChem can supply DDAC 80% (CAS 7173-51-5) as a bulk biocide/surfactant raw material, with the documentation appropriate to your market. To request current specifications, a COA or a quotation, contact the PolyBlueChem team.
Frequently Asked Questions
What should I look for when buying DDAC?
Confirm the CAS number (7173-51-5) and active content, check the free-amine figure and pH, choose the right form, and secure the SDS, COA and biocide regulatory statements.
What is the active content of DDAC?
The standard commercial grade is an 80% active aqueous solution, though other strengths and blends are available.
Is DDAC the same as benzalkonium chloride?
No. DDAC (7173-51-5) has two C10 chains; BAC (commonly 8001-54-5) is a mixture with one alkyl chain and a benzyl group.
What documents should come with a shipment?
At minimum an SDS and a per-batch COA, plus the applicable biocide regulatory statements for your market.
How should DDAC be stored?
Sealed, cool and out of direct sunlight, in corrosion-resistant containers, away from anionic materials and oxidisers.