Method and mixing unit for manufacturing isocyanates by phosgenesis of primary amines

The invention relates to a mixer-reactor of the rotor-stator type comprising a substantially rotationally symmetrical housing which is frontally delimited by a front plate and containing a mixing chamber having separate inlets for at least two substances and an outlet, said inlet for the first material is provided in the rotational axis of the mixing chamber and the inlet for the at least second material in the form of a plurality of rotationally symmetrically arranged to the rotation axis openings formed in the end plate to which one is assigned to axially slidable bolt, respectively, characterized in that in the end plate channels are arranged, which are oriented from the inlet for the first substance in the axis of rotation towards the outside.