Studies on the Physical Chemistry of (2,4-Dichlorophenoxy)acetic Acid in Two-phase Systems: Organic Solvent-Water

Abstract

The dissociation constants (p s K a ) of 2,4-D acid were determined in methanol-water mixtures of 10.9 to 38.9 wt.% methanol content. The Yasuda-Shedlovsky procedure was used to obtain the pK a value in zero-% methanol. The distribution of 2,4-D acid in twelve two-phase organic solvent + water systems and its dimerization in the organic phase were investigated. Values of the distribution coefficient (D HR), distribution constant (K D ), and dimerization constant (K dim) of 2,4-D were obtained. The influence of the structure and polarity of the investigated organic solvents, as well as that of pH of the aqueous phase, on the physical chemistry of 2,4-D in the two-phase systems are described.