Abstract: This invention relates to a process for carrying out reactions which primarily occur during the transport of compounds in the liquid phase or at the liquid-gas interface. Starting components are reacted with one another and/or with gases of the inner space in a multi-phase flow tube having a liquid ring flow which may contain dissolved and/or dispersed constituents. Any necessary heat exchange takes place between the liquid and the wall of the tube or the gases.

Abstract: A process for the production of polyamide-6 or corresponding copolyamides by hydrolytic polymerization wherein the low molecular weight secondary reaction products and the unreacted .epsilon.-caprolactam are separated off from the polyamide melt and directly condensed on the .epsilon.-caprolactam melt to be polymerized.

Abstract: A method for the separate discharge of the individual phase streams of a multiple component flow comprising a high viscosity slow flowing liquid or suspension and a gas flowing at at least 100 times faster with the volumetric ratio of the gas to the liquid being greater than 1:1. The multicomponent flow is transversely fed through an inlet and directly into a rotating helical channel for conveying liquid in one direction. The channel has a liquid outlet spaced from the inlet in the one direction and a gas outlet spaced from the inlet in the opposite direction. A gas shut-off is formed between the inlet and the liquid outlet so as to effect the discharge of gas through the gas outlet in the opposite direction during the conveying of the liquid by the helical channel to the liquid outlet in the one direction.

Abstract: Polybutylene terephthalates having a narrow molecular weight distribution, a low carboxyl group content and an intrinsic viscosity of from 0.2 to 1.4 dl/g can be continuously produced by transporting a molten reaction mixture of terephthalic acid mono- and/or bis-(hydroxybutyl) ester or low viscosity polybutylene terephthalate at 160.degree. to 300.degree. C.