Amide 結合을 가진 N-carboxybetaine類의 合成과 그 界面活性

Studies on the Synthesis and Surface Active Properties of N-carboxybetaine Derivatives Containing Amide Bond

Four novel amphoteric surfactants of N-(2-alkylamidoethyl)-N, N-dimethyl ammonioacetates were synthesized. The each reaction between four saturated fatty acids containing 10,12,14 and 16 carbon atoms and N, N-dimethylethylene diamine permitted to give the intermediate products, N-(2-alkylamidoethyl)-N, N-dimethylamines. Quaterinzation of these intermediates was permitted to form N-(2-alkylamidoethyl)-N, N-dimethylammonioacetates, whose sturctures were identified by CC, TLC, elemental analysis, IR spectrophotometry and ¹HNMR spectrometry. The products yielded from 48% to 58%. The isoelectric points were shown in the range of 4.30~6.64. It showed a tendency to learn to the acidic site and its range was broadened as increase of the hydrophobic group length. Surface tensions of the aqueous solution in the 10⁻⁶~10⁻¹mol/l of amidobetaines were measured. and the critical micell concentration(cmc) were shown in the range of 8.37x10⁻⁶~8.96x10⁻²mol/l, rcmcand were reduced to 32.3~38.2 dyne/cm. A linear relationship between log cmc and the number of carbon in the hydrophobic alkyl chain was presented by the formula of log cmc=2.38-0.5n, and the contribution-rate of n on the standard free energy change in micellization ∂(ΔG°m/∂n, was calulated as -0.5RT.