There are experimental reasons to perform adiabatic thermokinetic measurements applying a semibatch technique. Such measurements can be evaluated by transforming the semibatch data to equivalent batch mode data. To demonstrate this new evaluation method, adiabatic measurements were performed in two different adiabatic calorimeters using the alcoholysis of phenyl isocyanate as the model reaction. The reaction data obtained from these experiments agree well with former data from measurements in different batch calorimeters.