Kinetic study of the hydrolysis of ester with mineral acid by spectrophotometer at different temperature

Abstract

To determine the kinetic parameters and activation energy of the hydrolysis of ethyl acetate with hydrochloric acid monitored by spectrophotometry. The first order fits were automatically drawn and the values of the first order rate constants (k) were calculated using standard equations as part of the program. Acidic hydrolysis of ethyl acetate is essentially an irreversible and first order reaction whereas alkaline hydrolysis is an irreversible and second order reaction. Rate of reaction is the change in the number of molecules of reacting species per unit volume per unit time. In this hydrolysis of ethyl acetate with hydrochloric acid to accelerate the reaction mixture. A simple and sensitive kinetic spectrophotometric method presented for the determination of rate constant, order of reaction and activation energy. This method based on a kinetic investigation of ethyl acetate and hydrochloric acid at 35°C and 45°C temperature. The reaction followed spectrophotometrically by measuring the absorbance at 500 nm as a function of time. The initial rate and fixed time methods utilized for construction of calibration graphs successfully for the determination of rate constant, order of reaction and activation energy. The rate constant after calculation from the graphs was approximately k1 ≈ 0.00260 Sec-1 k2 ≈ 0.00322 Sec-1 by titration and spectrophotometric method respectively, order of reaction found to be first order and the activation energy for this reaction is 17.44 kJ/mol. One factor that influences the absorbance of a sample is the concentration (c). As the concentration increases, more radiation is absorbed and the absorbance increase. Therefore, the absorbance is directly proportional to the concentration.