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pp.63-71
Four novel amphoteric surfactants of N-alkoxyethylcarboxybetaine series were synthesized via Schotten-Baurnman reaction between four alkyl chlorides contaning 10, 12, 14 and 16 carbon atoms in their N-alkyl group and dimethylaminoethanol to give the intermediate products, alkoxyethyldimethylamine, Quaternization of these intermediates was permitted to form 2-(alkoxyethyldimethylarnmonio) acetates, whose structures were identified by elemental analysis. IR spectrophotometry and 1Hnmr spectrometry. The yield of the final products was shown in the range of 74~77% based on the yield of the intermediate products, Surface tension of the aqueous solution of the final products was measured. and the critical micelle concentrations(cmc) were shown in the range of 2.82×10-3~2.67×10-6mol/l, and the surface thension at erne was 35~43dyne/cm. Cmc was lowered gradually by the increase of carbon numbers in N-alkyl ether containing group. The isoelectric point was shown in the range of 4.08~6.03. It showed a tendency to lean toward the acidic site and its range was broadened as increase of the hydrophobic group length. A linear relationship between log erne and the number of carbon atoms(N) in the hydrophobic alkyl chain was shown in the relative equation of log cmc=2.49-0.50N.
