The reaction of ${eta}$-picoline with substituted benzoyl chlorides has been studied by means of conductometry under various pressures in acetonitrile. From the values of pseudo-first order and second order rate constants, the activation parameters (${Delta}V{ eq}$, ${Delta}{eta}{ eq}$, ${Delta}H{ eq}$, ${Delta}S{ eq}$ and ${Delta}G{ eq}$) and the pressure dependence of Hammett ${ ho}$ value were studied. The activation volume, the activation compressibility coefficient and the activation entropy were all negative. By increasing pressure the rate constant and Hammett ${ ho}$ value were increased, and the reaction mechanism was proceed in bond formation favored.