界面活性クラウンエーテル (第1報) : 長鎖アルキル基をもつアセタール型大環状ポリエーテル

概要

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Higher aldehydes acetalized with diethylene glycol were treated with diethylene glycol ditosylate in the presence of potassium t-butoxide to give a series of 2-alkyl-1, 3, 6, 9, 12, 15, 18-heptaoxacycloeicosane (Cn-20-crown-7). Although the obtained acetal crown ethers were found to be subject to hydrolysis, the ethers were stable in very dilute alkaline solution enough to evaluate the surfactant properties. The surfactant properties were compared with those of several type of polyoxyethylene (POE) nonionics with the same hydrophobic group and the same number of EO units. The acetal crown had rather lower cloud point and smaller critical micelle concentration (cmc) than those of nonionics with linear POE, indicating the less hydrophilicity of cyclic POE. No significant differences were found between the acetal crown and POE nonionics in respect of surface properties, surface tension above cmc and molecular area on absorption at air/water interface. The acetal crown catalized the reaction of alkylhalide with potassium phenoxide in organic solvent. The catalytic activity in benzene was significantly higher than that of dibenzo-18-crown-6.