Linear Free Energy Relationships in Solid State Reactions: Part III-Reactions of Zinc Acetate with Aniline Salts

Abstract

Reactions between anhydrous zinc acetate and a series of substituted aniline hydrochlorides have been studied in the solid state. The products, characterized by elemental analyses and spectral data are ZnCl₂^. 2(XC₆H₄NH₂). The kinetics of these reactions have been studied by the mass loss method. Energy of activation values are 26.9, 38.9, 57.7, 144.7, 92.8, 117.4, 97.4, 162.2 and 186.5 kJ mol^-1 for X=2-Cl, 3-Cl, 4-Cl, 4-1, 3-OCH₃, 4-F, H, 4-CH₃, and 4-OCH₃, respectively. A plot of energy of activation with Hammett 0 constants of the substituents is linear. Unsubstituted aniline salt and 4-iodoaniline hydrochloride show deviations which have been interpreted in terms of differences in crystal structure and size of these reactants. The reactions proceed by the formation of an adduct, which then decomposes with the loss of gaseous acetic acid.