Cocamidopropyl betaine
Lauramidopropyl betaine, the major component of cocamidopropyl betaine
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Names | |
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IUPAC name
{[3-(Dodecanoylamino)propyl](dimethyl)ammonio}acetate
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Other names
2-[(3-Dodecanamidopropyl)dimethylaminio]acetate
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Identifiers | |
61789-40-0 | |
ChemSpider | 19106 |
EC Number | 263-058-8 |
Jmol 3D model | Interactive image Interactive image Interactive image |
PubChem | 20280 |
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Properties | |
C19H38N2O3 | |
Molar mass | 342.52 g·mol−1 |
Vapor pressure | {{{value}}} |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references | |
Cocamidopropyl betaine (CAPB) is an organic compound derived from coconut oil and dimethylaminopropylamine.[1] It is a zwitterion, consisting of both a quaternary ammonium cation and a carboxylate. CAPB is available as viscous pale yellow solution that is used as a surfactant in personal care products. The name reflects that the major part of the molecule, the lauric acid group, is derived from coconut oil. Cocamidopropyl betaine to a significant degree has replaced cocamide DEA.
Production
Cocamidopropyl betaine can be viewed as the combination of cocamide and glycine betaine. It is however prepared by combining chloroacetic acid with the amide derived from dimethylaminopropylamine and lauric acid:
- CH3(CH2)10C(O)N(H)CH2CH2CH2N(CH3)2 + ClCH2CO2H + NaOH → CH3(CH2)10C(O)N(H)CH2CH2CH2N+(CH3)2CH2CO2− + NaCl + H2O
Specifications and properties
Cocamidopropyl betaine is used as a foam booster in shampoos.[2] It is a medium strength surfactant also used in bath products like hand soaps. It is also used in cosmetics as an emulsifying agent and thickener, and to reduce irritation purely ionic surfactants would cause. It also serves as an antistatic agent in hair conditioners. which most often does not irritate skin or mucous membranes. However, some studies indicate it is an allergen.[3][4][5] It also has antiseptic properties, making it suitable for personal sanitary products. It is compatible with other cationic, anionic, and nonionic surfactants.
CAPB is obtained as an aqueous solution in concentrations of about 30%.
- Active *NaCl 4.6 – 5.6%
Typical impurities of leading manufacturers today:
- Sodium monochloroacetate < 5 ppm
- Amidoamine (AA) < 0.3%
- dimethylaminopropylamine (DMAPA) < 15 ppm
- Glycerol < 3%
The impurities AA and DMAPA are most critical, as they have been shown to be responsible for skin sensitation reactions. These by-products can be avoided by a moderate excess chloroacetate and the exact adjustment of pH value during betainization reaction accompanied by regular analytical control.
Safety
CAPB has been claimed to cause allergic reactions in some users,[3][4][5] but a controlled pilot study has found that these cases may represent irritant reactions rather than true allergic reactions.[6] Furthermore, results of human studies have shown that CAPB has a low sensitizing potential if impurities with amidoamine (AA) and dimethylaminopropylamine (DMAPA) are low and tightly controlled.[7][8] Other studies have concluded that most apparent allergic reactions to CAPB are more likely due to amidoamine.[9][10] Cocamidopropyl betaine was voted 2004 Allergen of the Year by the American Contact Dermatitis Society.[11]
See also
References
- ↑ Christian Nitsch, Hans-Joachim Heitland, Horst Marsen, Hans-Joachim Schlüussler, "Cleansing Agents" in Ullmann’s Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a07_137
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- ↑ History of Allergen of the Year. contactderm.org