AOS in Household and Industrial Cleaning

Sodium alpha-olefin sulfonate (AOS, CAS 68439-57-6) is a building block of modern detergents. Its hard-water tolerance, rich foam and sulfonate stability make it useful in liquid and powder laundry detergents, dishwash, hard-surface cleaners and industrial cleaning – and it works in the high-hardness water that degrades cheaper anionics. This article covers where AOS is used in cleaning and how to formulate with it.

1. Why AOS in cleaning products

Property	Benefit in cleaning
Hard-water tolerance	Foam and detergency hold up where calcium and magnesium would precipitate cheaper anionics
Rich, stable foam	Good lather for hand dishwash and foam cleaners
Sulfonate stability	Stable in alkaline cleaners and across pH – no hydrolysis
Electrolyte tolerance	Behaves well with builders and salts in detergent formulations
Biodegradability	Readily biodegradable – important for detergent environmental profiles

2. Where AOS is used

Product	Role of AOS
Liquid laundry detergent	Primary or co-surfactant; hard-water detergency and foam
Powder detergent	Surfactant in spray-dried or agglomerated powders (92% grade)
Hand dishwash	Rich, stable foam and good grease removal
Hard-surface cleaner	Wetting and detergency in alkaline or neutral cleaners
Industrial and institutional cleaning	Alkaline cleaning, degreasing, CIP formulations
Textile wetting and scouring	Wetting agent tolerant of hard water and electrolytes

3. Formulating with AOS

Parameter	Typical practice
Active level (liquid detergent)	About 5 – 20% active
Active level (powder detergent)	About 5 – 15% active
Active level (hand dishwash)	About 8 – 20% active, with foam boosters
Co-surfactants	LAS, SLES, alcohol ethoxylates, amine oxides, betaines
Builders / chelants	Zeolites, citrates, phosphonates, or sodium carbonate in alkaline cleaners
pH	Neutral to strongly alkaline, depending on the product class

AOS pairs well with LAS (see the comparison): blending it into an LAS-based detergent improves hard-water tolerance and foam while keeping cost down.

4. The hard-water advantage

In hard water, LAS and soap lose performance as their calcium and magnesium salts become insoluble. AOS is a sulfonate with better hard-water tolerance, so a detergent built around AOS (or an AOS/LAS blend) keeps its foam and cleaning power where softer-water formulations would struggle. This matters most for markets with hard water, and for cleaning products used without a water softener.

5. Industrial cleaning

Alkaline cleaners – AOS is stable in alkaline formulations used for industrial degreasing and CIP.
Metal and surface cleaning – wetting and emulsification of oils and soils.
Textile processing – wetting, scouring and level dyeing in hard water.
Foam cleaning – AOS’s stable foam suits foam-based cleaning and foam barriers.

6. Dosage and blending (starting points)

System	Illustrative AOS contribution
LAS-based liquid detergent	Replace 10 – 30% of the LAS active with AOS
Hard-water dishwash	AOS as the main anionic, with amine oxide or betaine
Powder detergent	AOS as part of the anionic surfactant blend (92% grade)

These are starting points; build the formulation and confirm foam, detergency, viscosity and stability on the finished product.

Frequently Asked Questions

Why use AOS in detergents?

For hard-water tolerance, rich foam, sulfonate stability (including in alkaline cleaners) and good biodegradability – and to improve the performance of LAS-based detergents.

Is AOS better than LAS in hard water?

Yes. AOS is a sulfonate with better hard-water tolerance, so its foam and detergency hold up where LAS salts would precipitate. LAS remains cheaper in soft water or well-built formulas.

Can AOS be used in alkaline cleaners?

Yes – the sulfonate group is stable across a wide pH range, which suits alkaline industrial cleaning formulations.

Which grade is used in cleaning products?

The 92% powder for powder detergents, and the 34-36% liquid for liquid detergents and cleaners.