Abstract: Separation of volatile components from the polymer melts formed during the homopolymerization of ethylene or the copolymerization of ethylene with other copolymerizable compounds at elevated pressures and elevated temperatures by countercurrent treatment with ethylene. Superior separations are obtained by the process.

Abstract: The preparation of aldehydes by the reaction of olefins with carbon monoxide and hydrogen in the presence of water and water-soluble rhodium/phosphine complex compounds as catalysts. The method comprises first cooling the organic part of the liquid phase to 70.degree. to 90.degree. C. in a stripping column by treatment with the carbon monoxide/hydrogen mixture fed into the reactor, further cooling the organic part to 20.degree. to 40.degree. C. by heat exchange with the feed olefin, subsequently relieving the pressure with the consequent formation of waste gas and aqueous and organic phases, and finally separating the phases so as to recover substantially all of the catalyst and the heat of reaction.