The theory of mass transfer accompanied by chemical reaction has been used for studying the kinetics of alkaline hydrolysis of 2-ethylbutylformate at different temperatures and ionic strengths of aqueous alkaline solution. Experiments have been conducted in a stirred cell having a flat liquid-liquid interface. For aqueous phases containing 1-3 kmol/m(3) sodium hydroxide, the alkaline hydrolysis conforms to the fast pseudo-first order reaction regime. The system is of considerable practical importance and can be successfully employed for the measurement of the interfacial area of a mechanically-agitated and flooded packed-bed liquid-liquid contactor.