A process for preparing polycarbonate by the phase interface process in the presence of at least one catalyst, wherein immediately after the optionally first addition of the at least one catalyst, from 0.01 to 20 J/kg of mixing energy is introduced into the system comprising the at least one catalyst within a time of from 2 to 1200 s. A mixture, an organic phase, and a process for distributing at least one catalyst in a system comprising an organic phase and an aqueous phase are also disclosed herein.