Abstract: An improved process for purification of glycerol obtained from natural sources comprising alkalizing a glycerol-containing crude mixture in the presence of air for oxidation, evaporating the mixture in a thin-layer evaporator with redistillation of the residue, rectification and reevaporation in a packed column characterized by low-pressure-loss plates with a falling-film evaporator designed for internal and external partial condensation and to separate off unwanted constituents of the mixture, bleaching the product with activated carbon and separating the bleach in known manner.

Abstract: The instant invention is directed to a process for stripping of a residual component from a liquid having a viscosity of from 300 to 10,000 poises in which the liquid flows in the form of a ring flow supported by a gas stream flowing in the core, through a tube into a separator vessel, the tube having a continuous coil shape and a conduit diameter to helix diameter of from 0.1:1 to 0.04:1, the improvement comprising adding to the gas stream from 10 to 90%, by weight, of externally generated steam and/or an inert gas at an adjusted pressure of from 50 m bars to 1 bar in the separator vessel for a gas and/or steam velocity in the tube of from 100 m/sec to the speed of sound. The added gas and/or steam generates thorough transverse mixing in the liquid ring flow.

Abstract: An improved process for the production of polyamides of low extract content by the activated anionic polymerisation of at least one lactam containing at least 5 ring members at temperatures above the melting point of the polyamide in a continuously working polymerisation apparatus, optionally followed directly by shaping, the improvement comprises treating the polyamide melt obtained by polymerising said lactam in said polymerisation apparatus with water or steam and subsequently freeing it from volatile constituents by evaporation before the polyamide melt is discharged into the open.