Abstract: This invention relates to a process for carrying out continuous demonomerization and postpolymerization of Polyamide 6 melts and a reactor for carrying out this process. The reactor of this invention has a cylinder with a horizontal axis around which an interior rotor shaped like a cage rotates. The reactor can be partially filled with polymer melt. There is a multitude of elements along the periphery of the rotor which partly dip into the melt and serve to convey the melt through the reactor, generate new surfaces and mix and homogenize the melt as the polymer melt undergoes demonomerization and postpolymerization under vacuum.