Cocoamidopropyl betaine

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Structural formula of the main component lauramidopropyl betaine

Cocamidopropyl betaines (CAPB) are a collective name for certain betaines that are derived from coconut fatty acids . Lauramidopropyl betaine (C 19 H 38 N 2 O 3 ) is the most important . Synonyms for cocoamidopropyl betaine are CAPB, COCAMIDOPROPYL BETAINE ( INCI ), alkylamidobetaines, coconut (fatty acid amidopropyl) betaine and 2- [3- (dodecanoylamino) propyl-dimethylazaniumyl] acetate ( IUPAC ).

Extraction and presentation

To produce CAPB, first coconut fatty acids (i.e. in particular fatty acids with eight to eighteen carbon atoms in the compound) or their triacylglycerols are amidated with the aid of 3-aminopropyldimethylamine . This is followed by carboxymethylation with chloroacetic acid , which takes place under basic conditions.

In 2003 around 100 kilotons of 30% goods were produced worldwide.

properties

CAPB belong to the amphoteric surfactants , so they are zwitterions . The positive charge is on the quaternary nitrogen atom , the negative on the carboxylate group . They behave like amphoteric surfactants in neutral solutions , like cationic surfactants in acidic solutions and like anionic surfactants in alkaline solutions . The CAS number is 61789-40-0 and the PubChem registration number is 20280.

use

CAPB are used in particular as cosurfactants in cosmetics and household chemicals, especially in shower gels , shampoos and liquid soaps , but also in fabric softeners or dishwashing detergents . In addition to their cleansing properties, they have an antistatic effect, improve the feel of the skin and the manageability of hair, but can also be used to improve the foam quality and as viscosity regulators. In addition, CAPB have an antiseptic effect. The good mucous membrane tolerance also favors the use in cosmetic articles for babies.

safety instructions

CAPB are generally considered to be kind to the skin and environmentally friendly. They are classified in the water hazard class WGK 1.

Nevertheless, they are suspected of being responsible for the occurrence of allergic contact eczema, especially with shampoos and on the face or scalp, less often on the hands. In some cases this could also be irritant contact eczema. Various studies also provide evidence that amidoamine or DMAPA , which are often found as impurities in commercially available CAPB mixtures, could actually be the cause of allergic contact eczema.

Individual evidence

  1. ↑ a b c d e Entry on cocoamidopropyl betaine. In: Römpp Online . Georg Thieme Verlag, accessed on August 13, 2017.
  2. ↑ a b entry on betaine. In: Römpp Online . Georg Thieme Verlag, accessed on August 13, 2017.
  3. ↑ a b c Rolf Pohling: Chemical reactions in water analysis . Springer, Berlin, Heidelberg 2015, ISBN 978-3-642-36353-5 , pp. 338 ( limited preview in Google Book search).
  4. ↑ Information on CAPB at haut.de , accessed on August 13, 2017.
  5. ^ Robert L. Rietschel, Joseph F. Fowler, Alexander A. Fisher: Fisher's Contact Dermatitis . 6th edition. PMPH-USA, 2008, ISBN 978-1-55009-378-0 , pp. 287 ( limited preview in Google Book search).