Coconut diethanolamide is a mixture of fatty acid diethanolamides, primarily derived from coconut oil fatty acids (notably lauric acid) reacted with diethanolamine. The chemistry dates back to mid‑20th century surfactant research when fatty acid amides were recognized as effective nonionic surfactants. The compounds are synthesized by amidation or condensation of coconut fatty acid esters or coconut acid with diethanolamine under alkaline catalysis, typically at temperatures around 150–170 °C. A molar ratio of approximately 1 : 1 between fatty acid (or methyl ester) and diethanolamine yields a product with minimal free diethanolamine; ratios of 1 : 2 produce lower‑grade mixtures containing byproducts and residual amine. The resulting product is a viscous, yellowish to pale liquid identified by CAS number 68603‑42‑9.
Its main application is as a foaming agent and emulsifier in personal and industrial care products including shampoos, bath soaps, cleansing liquids, and hand cleaners. It stabilizes foam, improves viscosity, and acts as a viscosity enhancer or antistatic agent in shampoos and conditioners. It has been used for decades in formulations at concentrations from about 1 % up to 25 %. Occupational exposure to products containing cocamide DEA has occasionally caused contact dermatitis in workers using hand-cleaning creams, soaps, or metalworking fluids containing the compound.
More recently, research has explored coconut diethanolamide as a bio-based substitute for petroleum-derived polyols in producing rigid polyurethane-urea foams. One study demonstrated that industrial-grade coconut fatty acid diethanolamide can serve directly as a biopolyol precursor in rigid foam synthesis, enabling shorter gel and cream times through intrinsic amine autocatalysis, and yielding foam with thermal conductivity and compressive strength comparable to standard rigid polyurethane foam. The approach maps toward high-performance, renewable insulation materials.
Safety profiles have been evaluated in genotoxicity and carcinogenicity studies. Coconut diethanolamine condensate is classified by IARC as Group 2B, meaning possibly carcinogenic to humans, based on dermal studies in mice showing increased hepatocellular tumors associated with free diethanolamine impurities. In carcinogenicity bioassays, the tumour response in mice correlated with residual free diethanolamine (\~18 %) rather than the amide mixtures themselves, and no tumour effects were observed in rats. Genotoxicity assays including bacterial mutation and mammalian cell tests, as well as in vivo rodent micronucleus tests, were negative for mutagenicity, indicating no intrinsic genotoxic potential apart from the impurity component. Safety assessments recommend limiting free diethanolamine content and restricting use to rinse‑off formulations or brief contact products.
Environmental use includes applications in laundry detergents, cosmetics, polishing and metalworking fluids as an antistatic or emulsifying agent. Its utility in lubricants and industrial hand cleaners highlights its versatility in surfactant technology. Occupation-related allergic reactions, though uncommon (around 1% in patch-tested clinic populations), warrant awareness among industrial hygiene professionals.
In summary, coconut diethanolamide is a fatty acid‑derived diethanolamide surfactant historically developed for personal care and industrial formulations. It is produced by condensation of coconut fatty acids with diethanolamine under alkaline conditions. Its primary uses include foam stabilization and emulsification in consumer and industrial products, along with emerging applications in bio-based rigid polyurethane foam production. Safety is dependent on controlling residual diethanolamine impurity; while the amide mixture itself is not genotoxic, impurities can drive adverse effects. Continued research examines its performance as a renewable bio-based alternative in polymer and foam applications.
References
Aalto‑Korte K, Pesonen M, Kuuliala O, Suuronen K (2014) Occupational allergic contact dermatitis caused by coconut fatty acids diethanolamide. Contact Dermatitis 70(3):169–174 DOI: 10.1111/cod.12151
Leng X, Li C, Cai X et al. (2022) A study on coconut fatty acid diethanolamide‑based polyurethane foams. RSC Advances 12:13548–13556 DOI: 10.1039/D2RA01361D
Fiume MM (2013) Safety assessment of diethanolamides as used in cosmetics. International Journal of Toxicology 32(2 Suppl):3S–29S DOI: 10.1177/1091581813486300
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