How to Buy AOS: 92% Powder and 34-36% Liquid Grades

Sodium alpha-olefin sulfonate (AOS, CAS 68439-57-6) is bought in two forms – a 92% powder and a 34-36% liquid – and the specification decides whether a batch performs in your formulation. This guide covers the parameters to confirm, how to choose between powder and liquid, packaging, documents and a supplier checklist.

1. The two specifications

Property	AOS 92% (powder)	AOS 34-36% (liquid)
Appearance (25 deg C)	Light-yellow powder	Light-yellow liquid
Odour	No strange odours	No strange odours
Active matter (%)	90 – 94	34 – 36
Unsulfated matter (%)	Max 3.0	Max 1.75
Inorganic salt (%, as Na₂SO₄)	Max 5.0	Max 1.5
Free alkali (%, as NaOH)	Max 1.0	Max 0.3
Colour (Klett, 5% aqueous solution)	Max 90	Max 80
Water (%)	Max 3.0	–

2. What each parameter means for you

Parameter	Why it matters
Active matter	The surfactant you are paying for; it sets the dosage in your formula
Unsulfated matter	Unreacted olefin; high levels affect foam, odour and performance
Inorganic salt (as Na₂SO₄)	Affects viscosity and electrolyte balance in the finished product
Free alkali (as NaOH)	Affects pH; important for skin-contact and acid-sensitive formulations
Colour (Klett)	Matters for clear and light-coloured products; lower is better
Water	Powder flow, caking and shelf life

Compare prices on a cost per unit of active matter basis, not per tonne of product – a higher-active grade is not necessarily more expensive to use.

3. Powder or liquid?

Form	Advantages	Considerations
Powder (92%)	High active; lower freight per unit active; suits powder detergents and solid formulations	Needs dissolving; dust; hygroscopic – keep sealed
Liquid (34-36%)	Ready to pump and blend; easiest for liquid formulations; no dissolving step	Pays to ship water; protect from freezing

For a liquid shampoo or detergent plant, the liquid grade saves a dissolving step; for powder detergents or long-distance shipping, the powder is often more economical. Pick by product form and logistics.

4. Packaging

Grade	Packaging
Powder (92%)	25 kg PP/PE bags; 1000 kg jumbo bags; palletised for container shipment
Liquid (34-36%)	200 L drums; 1000 L IBCs; ISO tanks; bulk

Store the powder sealed and dry (it is hygroscopic); protect the liquid from freezing and from prolonged high temperatures.

5. Documents to request

Specification sheet – the values the supplier guarantees.
Certificate of analysis (COA) per batch – active matter, unsulfated matter, inorganic salt, free alkali, Klett colour and water.
Safety data sheet (SDS) – handling, storage and first aid.
Third-party inspection (for example SGS/BV) on request.

6. Supplier checklist

States active matter, unsulfated matter, salt, free alkali and Klett colour in writing.
Offers both the powder and the liquid grade, so the form can follow your process.
Provides a per-batch COA and SDS.
Confirms the hydrophobic chain cut (for example C14-C16) if your formulation specifies it.
Quotes FOB or CIF to your port, with lead time.

7. Getting the best terms

AOS is a large-volume commodity surfactant, and China is a major producer, so supply is broad and competitive. Compare quotes on cost per unit of active matter, and for repeat production quote an annual or quarterly volume. Tell us the grade, the active matter and the tonnage for a quotation.

Frequently Asked Questions

What is the active matter of AOS?

The powder is typically 90-94% active; the liquid is 34-36% active. Active matter is the surfactant content and sets your dosage.

Should I buy the powder or the liquid?

Powder for powder detergents and long-distance shipping (less water to pay for); liquid for liquid formulations, where it avoids a dissolving step.

How is AOS packed?

Powder in 25 kg bags and 1000 kg jumbo bags; liquid in 200 L drums, 1000 L IBCs, ISO tanks and bulk.

What documents should I get?

A specification sheet, a per-batch COA (active matter, unsulfated matter, salt, free alkali, colour, water) and the SDS, plus third-party inspection on request.