characterised in that chlorinated aromatic hydrocarbons are added to the organic phase used in the phase interface process preferably in an amount of 0 001 to 90 wt particularly preferably 30 to 50 wt referred to the organic phase surprisingly the residual monomer content and the oligomer content in the polycarbonate after isolation of the polycarbonate at a purity of the isolated polycarbonate of 99 95 to 99 9999 is thereby reduced by 5 to 50 compared to the residual monomer content and the oligomer content in the polycarbonate solution surprisingly the reduction of the residual monomer content and oligomer content may be achieved directly during the process of the production of the polycarbonate and not only in a downstream connected extrusion step as described in the literature de a 29 17 396 u s pat no 4 306 057 suitable solvents according to the invention are chlorinated aromatic hydrocarbons preferably monochlorobenzene or dichlorobenzene also chlorinated toluenes and mixtures of these compounds monochlorobenzene being particularly preferred the polycarbonate is produced by the so called phase interface process this process for polycarbonate synthesis has been described many times in the literature including for example in schnell u201c chemistry and physics of polycarbonates u201d polymer reviews volume 9 interscience publishers new york london sydney 1964 p 3370 d c prevorsek b t debona and y kesten corporate research center allied chemical corporation morristown n j 07960 u201c synthesis of poly ester carbonate copolymers u201d in journal of polymer science polymer chemistry edition vol 18 1980 pp 75 90 d freitag u grigo p.