Stearamidopropyl Dimethylamine is a chemical compound obtained from rapeseed oil, 

The name describes the structure of the molecule:

• Stearamidopropyl is a group derived from stearic acid, a long-chain fatty acid with 18 carbon atoms, modified by the addition of an amide group -CONH₂ and a propyl group -CH₂CH_3.
• Dimethylamine refers to an amine group -NH2 modified by the addition of two methyl groups -CH3.

The synthesis process takes place in different steps:

• Preparation. The first step in the process involves the preparation of stearic acid, a saturated fatty acid used in the production of detergents, soaps and cosmetics. It can be obtained from fats and oils through the saponification of triglycerides.
• Amidation. This is a reaction of stearic acid with ammonia under heat to produce stearamide.
• Alkylation. Stearamide reacts with dimethylamine, a type of secondary amine, in a process known as alkylation. This reaction leads to the formation of Stearamidopropyl Dimethylamine
• Purification. The final step in the process involves the removal of all unreacted materials and by-products from the reaction mixture to obtain pure Stearamidopropyl Dimethylamine.

It appears as a yellowish powder or colourless liquid.

What it is for and where

Cosmetics

Stearamidopropyl Dimethylamine is used in cosmetics as a cationic surfactant usually in percentages lower than 5%.

Antistatic agent. Static electricity build-up has a direct influence on products and causes electrostatic adsorption. The antistatic ingredient reduces static build-up and surface resistivity on the surface of the skin and hair.

Added to shampoos instead of silicone compounds, it slides the hair adhering to their surface.

Safety

The Cosmetic Ingredient Review Panel (Panel) examined the safety of fatty acid amidopropyl dimethylamines, which act primarily as antistatic agents in cosmetic products. Relevant animal and human data examined for these indicate that they are potential skin sensitisers that may be due in part to the sensitising impurity, 3,3-dimethylaminopropylamine. The Panel concluded that fatty acid amidopropyl dimethylamines are safe as cosmetic ingredients when formulated in a non-sensitising manner, which can be based on a quantitative risk assessment  (1).

Chemical safety

Commercial applications

Hair Conditioning Agent. Stearamidopropyl Dimethylamine is used in conditioners and hair treatments to detangle and condition the hair, making it soft and manageable.

Emulsifier in Cosmetic Products. It is used in creams and lotions to help mix water and oils, creating a uniform texture.

Antistatic Agent. Used in hair products to reduce static electricity, making the hair more manageable.

Silicone Substitute. It can be used as an alternative to silicones in hair products to improve shine and softness without weighing hair down.

Thickening Agent. It is used to increase the viscosity of cosmetic products.

• Molecular Formula   C₂₃H₄₈N₂O
• Molecular Weight   368.65
• CAS   67799-04-6

• UNII   9070YRE8OF    P1IO9HNJ3V
• EC number  267-101-1 
• Nikkaji     J425.569K

Synonyms:

Lexamine ; N-[3-(Dimethylamino)propyl]stearamide; Stearamidopropyl dimethylamine; Octadecanamide; Stearamidopropyldimethylamine

References_____________________________________________________________________

 (1) Burnett, C. L., Boyer, I., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., ... & Heldreth, B. (2019). Safety assessment of fatty acid amidopropyl dimethylamines as used in cosmetics. International journal of toxicology, 38(1_suppl), 39S-69S.