The kinetics of reaction between acetic acid and epichlorohydrin carried out in the presence of DMF or DMSO was studied. In addition, the conductivity of the reaction mixture was measured. The conductivity was found to increase considerably as the reaction proceeded. This was explained in terms of the formation of new effective forms of catalysts : the ammonium salt (in case of DMF) or sulphonium salt (for DMSO). A reaction scheme has been proposed, taking into account the active catalyst forms. The set of kinetic equations describing the reaction has been developed and the appropriate rate constants evaluated.