Surface Active Crown Ethers. VIII.

Abstract

Amphiphilic monoaza crown compounds (2 a-f) and diaza crown compounds (3 b and 4 a-c) bearing side chains with cation-binding ability were prepared by the method shown in Scheme-1. Cloud points, complexing stability constants (log K'1) with alkali metal cations (Na+ and K+) in methanol, and phase-transfer catalytic activity were examined for the products, and the data were compared with those of reference compounds. Among amphiphiles having almost the same HLB (Hydrophile-Lipophile Balance), cloud point height was in order of (5) > (2) > (3 b), (4). This was explained as due to the structural effects of two hydrocarbon chains in the hydrophilic moiety of the surfactants. The cloud points of (2), (3 b) and (4) increased by the addition of an alkali metal salts (NaCl or KCl) as reported in the case of (5). The stability constants (log K'1) of (2) were lower than those of (5) with the same number of ether oxygen atoms, and log K'1 increased with the number of ether oxygens in each series. Log K'1 of diaza crown ether series (3 b, 4 a-c) was reduced by the introduction of ether oxygens. Depending on the reagent used (NaI or KI), (2) and (4) exhibited higher phase-transfer catalytic efficiencies than those of the reference compounds (5 d) and (7). These efficiencies may be closely related to both log K'1 and HLB of the complexes composed of azacrown compounds and the reagents.