New Application of Crown Ether. V. The Effect of Crown Ethers on the Acid-Base Interaction between 2,4,4',6-tetranitrodiphenylamine and Primary Amines in Benzene

Article abstract of DOI:10.1246/bcsj.54.458

The effect of crown ethers on the acid-base interaction of 2,4,4',6-tetranitrodiphenylamine (HA, λ_max 380 nm, pK_a = 8.88 in water) with primary amines (RNH2) in benzene was investigated spectrophotometrically.Crown ethers assisted strongly the formation of association complexes, RNH3⁺*crown ether*A^-, which existed as a single chemical species (λ_max 478 nm) assignable to "crown ether-separated ion pair".The effect of the steric factors of various primary amines on the equilibrium to form the association complex was discussed on the basis of the equilibrium constants and thermodynamic parameters of the systems involving 18-crown-6 and benzo-18-crown-6.