KINETICS BY THERMOMETRY - AN ALDOL CONDENSATION REACTION

The principles of 'thermokinetic' experiments have been described, whereby the initial rates of chemical reaction in solution are determined by following the temperature rise in an adiabatic system; data are obtained within the first few seconds of mixing, and at rates of the order of one measurement s(-1). The procedure has been applied to the base-catalysed condensation reaction of acetone to form diacetone alcohol, an exceptionally difficult reaction to follow because of the small extent to which the reaction proceeds. At 26 degrees C, the equilibrium constant for the base-catalysed ionisation of acetone has been established as having a value of 1.2(9) l mol(-1) while the rate constant for the ionic dimerisation has the value 2.5(2) x 10(-3) mol l(-1) s(-1).