Pseudocationic nonionic surfactants

Addition of ethylene oxide and propylene oxide to fatty amines prepared from naturally occurring fatty acids encounters no difficulties. The reaction results in surfactants of mainly nonionic character those are characterised by better compatibility with anionics and moderate toxicity in comparison to initial amines. The ethoxylated fatty amines found application in textile finishing, acidic cleaners and cosmetics. Commercial ethoxylated fatty amines are known, for example, as Ethomeen , Genamin C/O/S/T , Imbentin-CAM/OTM , Marlazin , and Rhodameen/Cemulcat series of Akzo Nobel, Clariant, Kolb, Condea, and Rhodia, respectively. 

There are some nonionics that turn, under certain conditions at least partially, into cationic surfactants, which provides them the specific behaviour. Typical representatives of pseudocationic nonionic surfactants are long-chain tertiary amine oxides prepared by oxidation of tertiary amines, aliphatic, as N-lauryldimethylamine, or cyclic, as N-alkyl piperidine, by hydrogen peroxide  

Commercial amine oxide contains some amount of unoxidised tertiary amine that may account for some of the cationic behaviour of the product, particularly at low pH. The formation of semipolar N-0 bonds both rises affinity to water and highly reduces the basic character of the amine so that the transition into a salt becomes possible at low pH only or as a result of mixed micelle formation with an anionic surfactant at neutral pH [49, 50]  

Amine oxides of the same kind are manufactured by reaction of alkanoic acids and their esters with N,N-dimethyl-l,3-propanediamine and subsequent oxidation of the amino amide by hydrogen peroxide [9]  

Mild amine oxide with hydroxyethyl groups in the polar moiety can be also produced by oxidation of ethoxylated fatty amine. 

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Ethylene oxide adds easlily to an alkyl amine without catalyst forming alkyl diethanol amines or ethoxylated alkyl amines as mentioned previously (pseudocationic nonionics as discussed in Sec. 1.2.6). Primary amine and acylated polyamine ethoxylation brings forth milder and low-toxic surfactants. 

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