Alkyldimethyl betaines

Surface tension measurements of betaines, especially of alkyldimethyl betaines, have been reported repeatedly. For alkyl betaines with increasing chain lengths of the alkyl group, the results for surface tensions above the CMC, given in Table 15.6, have been reported (41). 

SCHEME 1.1 Preparation of alkyldimethyl betaines and alkylamidopropyl betaines. 

Alkylglycines, alkylaminopropionates and alkyldimethyl betaines are not hydrolysed by either acids or alkalis. Imidazoline derivatives are hydrolysed by acids to fatty acid and an ethylenediamine derivative. Alkylami-dobetaines are converted by acids to fatty acid and a short-chain dimethylbetaine. 

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