The five kinds of α, ω-type amphoteric surfactants were synthesized from 1, 12-dibromododecane. The chemical formula and abbreviation of these surfactants are as follows.
α, ω-NB : R=CH
2COO
-α, ω-NP : R=CH
2CH
2COO
-α, ω-SB : R=CH
2CH
2CH
2SO
3-Critical micelle concentration (cmc), surface tension at cmc (γ
cmc), area/molecule at air-water interface, anti-static power and catalytic activity on the reaction of octyl bromide with saturated aqueous potassium iodide were determined. The cmc values increased in the order α, ω-TB<α, ω-PB<α, ω-SB<α, ω-NP<α, ω-NB. The order of the increase in the ability of lowering γ
cmc was α, ω-SB<α, ω-PB<α, ω-TB<α, ω-NP<α, ω-NB. The area/molecule increased in the order α, ω-TB≈α, ω-NB<α, ω-NP<α, ω-PB<α, ω-SB. No significant difference in anti-static power and the catalytic activity was observed among the surfactants. These results were discussed by comparison with α-type amphoteric surfactants such as alkylthiobetaine,
N-alkylammoniumbetaine and
N-alkylpyridinium-3-carboxylate.
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