Alpha Olefin Sulphonate (AOS)

Alpha olefin sulfonate is a mild anionic surfactant, characterized by high-foaming and strong emulsifying properties. Other advantages include excellent surface activity, great hard-water resilience, and good dispersion of calcium soap.

GENERAL INFORMATION

Chemical name: Alpha Olefin Sulphonate (AOS)

CAS No.: 68439-57-6

Molecular formula: CnH2n-1SO3Na (n= 14 – 16)

Standard executed: GB/T 20200-2006 

Packaging: in 200KG plastic drum (35% solution); in 25 KG kraft paper bag (92% powder)

Contents

Description

A-olefin sulfonate is mostly derived from coconut oils. 

Alpha olefin sulfonates are typically created by processes such as ethylene oligomerization, or by the Fischer-Tropsch process of synthesis. The sulphonation process starts inside a continuous thin film reactor. High-temperature hydrolysis reacts with sultones to form a mixture of cyclic sulfonate esters and alkene sulfonic acids. This is followed by incorporating aqueous sodium hydroxide to neutralize the mix. Neutralization and hydrolysis are carried out in isopropanol instead of water in order to form Alpha olefin sulfonates in solid form.

Alpha olefin sulfonate features excellent cleaning and degreasing properties, strong wetting effect, foam booster, slight viscosity enhancer. It’s compatible with other surfactants, including amphoteric and non-ionic co-surfactants.

It’s gentle on the skin, without drying effects, which makes it ideal for making sulfate-free cleansing products. Those features, along with decent biodegradability, lead to the high popularity of Alpha olefin sulfonate as a cosmetic ingredient. In general, non-sulfate anionic surfactants are gradually becoming the prime solution for use in personal care cleansing products, particularly for scalp and hair care.

The most common AOS used in cosmetics is sodium C14-16 olefin sulfonate. This multifunctional variety can act as a detergent, emulsifier, and wetting agent. Properly formulated, it enhances viscosity, foaming properties, and the production of a stable lather.

Alpha olefin sulfonate can be added to formulas on its own, in a range of 4-30% of the final product. The concentration depends on desired properties, such as foaming and cleansing effects.

Technical specification

Items Standards:
(35.2% solution)
Standards:
(92% powder)
Classification
Anionic surfactant
Anionic surfactant
Appearance(25℃)
Light yellow liquid
Light yellow powder
Active matter content, %
33.0-36.0
90.0-94.0
Colour and Lustre
100 MAX
100 MAX
Sulfated compounds content, %
2.0 MAX
5.0 MAX
Sodium sulfate (Na2SO4) content, %
1.0 MAX
6.0 MAX
Free alkali (NaOH) content, %
1.0 MAX
1.0 MAX

Stability/Shelf life

Two years under proper storage. Store in a dry, cool place, away from moisture and heat.  

Alpha olefin sulfonate is stable at an extensive pH range and suitable for use in acidic environments.

Manufacturing

Alpha olefin sulfonate is a chemical compound composed of long-chain sulfonate salts made by the process of sulfonation of alpha-olefins. Alpha-olefin sulfonate is produced by oligomerization of ethylene, or by Fischer-Tropsch synthesis. The process is followed by purification. 

Industry use

Alpha olefin sulfonate’s primary use is in washing powder, liquid detergents, and soaps. Other applications include the textile, printing, and dyeing industries as well as the petrochemical industry. Alpha olefin sulfonate is additionally used as an industrial foaming agent, wetting agent, concrete density improver, and pesticide emulsifier. 

Consumer use

Alpha olefin sulfonate is commonly used as a surfactant in personal care products, such as sulfate-free shampoo, liquid and bar soaps, hand sanitizers, bath lotions, bubble baths, and facial cleansers, as well as in various household products such as dishwashing liquids and vehicle wash liquids. 

Solubility

Alpha olefin sulfonate is characterized by good solubility, suitable for use in liquid detergents. 

Common synonyms

  • Sodium alpha-olefin sulfonate
  • Sodium tetradecene sulfonate
  • Linear alpha-olefin
  • α-olefin sulfonate
  • Sodium a-olefin sulfonate
  • Sodium c14-16 olefin sulfonate

Ask an expert

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In brief, AOS has better resistance to hard water than LABSA, and it also has better foaming property. However, at present, LABSA is cheaper than AOS and is more accessable.

It depends on your product application and manufacturing method. To produce liquid detergents, AOS solution would be your choice. To produce powder detergents by a spray drying tower, AOS solution is the better choice. However, to produce powder detergent by dry mixing or agglomeration, AOS powder may be the only option.

Yes AOS has very good compatibility with LABSA in detergent solution.  A combination of LABSA and AOS in certain proportions can yield synergistic detergent action. As repitive experiments show, when LABSA and AOS are added at a proportion of 4:1 (by weight) in a detergent formula, it results in the best performance of a given total active matter content.

STPP-Angie-Liu

Angie Liu

Product Manager