Abstract: A process for the separation of residues of toluenediisocyanate production from mixtures containing high boiling residues, toluenediisocyanate and solvent by evaporation in said residue at a minimum of 5.degree. C above the boiling point of the higher boiling of the components consisting of toluenediisocyanate and solvent. The mixture is fed into the central portion of an evaporator equipped with a helical agitator operative to provide a material flow moving centrally downwards and peripherally upwards.

Abstract: Particulate olefin polymers are prepared by catalytic polymerization of monoolefins in an auxiliary liquid containing the monomers to be polymerized in dissolved form and the particulate polymer product in suspended form. The reaction mixture is recycled in a loop to which the starting materials are fed and from which the particulate polymer formed is removed. The essential features are (a) that a side stream is branched off from the loop, (b) that the side stream is caused to pass through a separating zone in which particulate olefin polymer is separated by centrifugal acceleration at temperatures and pressures in the same range as present in the loop and (c) that the separated particulate olefin polymer is discharged through flashing means.