Abstract: Cocamidopropyl betaine was synthesized using coconut fatty acid methyl ester,N,N-dimethyl propylene diamine,chloroacetic acid and NaOH as starting materials,and KOH as catalyst.Effect of factors such as molar ratio of N,N-dimethyl propylene diamine to coconut fatty acid methyl ester,dosage of catalyst,reaction temperature and reaction time et al on main reaction (synthesis of cocamidopropyl dimethylamine) was examined.Results showed that optimum conditions were screened out as follows:n(N,N-dimethyl propylene diamine)∶n(coconut fatty acid methyl ester)=1.15∶1;w(catalyst)=3.0%;reaction temperature 210 ℃;reaction time 25 min.Yield of the coconut fatty acid methyl ester achieves 99.70%.The structure of the targeted product was characterized with FTIR,MS and HPLC.

Key words: cocamidopropyl betaine, coconut fatty acid methyl ester, N,N-dimethyl propylene diamine, cocamidopropyl dimethylamine