Abstract: Copolymers of ethylene with acrylates or solutions of free acrylic acid in acrylates are prepared in a continuously operated tubular polymerization system at high pressures and temperatures by feeding a mixture of ethylene, acrylate, initiator and, if appropriate, regulant into the polymerization system in the form of a main stream at the inlet point thereof and at the same time through two or more secondary streams, secondary streams (I) being metered in at points where the reaction temperature has just exceeded a maximum temperature due to the heat of polymerization and secondary streams (II) at points which, relative to the direction of flow of the ethylene, are upstream of the feed points of secondary streams (I) and upstream of the respective maximum temperature.

Abstract: A process for the continuous production of an ethylene copolymer by compressing a mixture of ethylene and comonomer in a pre-compressor and a post-compressor, copolymerizing the mixture in a polymerization zone at a high temperature and high pressure, transferring the reaction mixture into a high pressure product isolation zone, from there into a low pressure product isolation zone and thereafter into a discharge extruder, and recycling the greater part of the unconverted monomer into the polymerization process and passing a small part of the unconverted gas into a low temperature isolation zone, in which process a small part of the gas recycled from the high pressure product isolation zone is passed into the low temperature isolation zone, which is preferably under a pressure of from 10 to 30 bar and at from -10.degree. to -50.degree. C., and all the gas taken off the low pressure product isolation zone is fed to the pre-compressor.

Abstract: A continuous process for the manufacture of ethylene copolymers under high pressure and at high temperature in a polymerization zone, with transfer of the reaction mixture into a high pressure product isolation zone and from there into a low pressure product isolation zone, and recycling of the unconverted gas from the high pressure product isolation zone into the polymerization zone and from the low pressure product isolation zone into a low temperature separator, from where the comonomer separated off is recycled to the polymerization process, while the ethylene is discharged as off-gas. The gas taken off the low pressure product isolation zone is preferably compressed to from 10 to 20 bar and cooled to from -10.degree. to -30.degree. C. before it is fed into the low temperature separator. There is a substantial improvement in the efficiency of separating off the comonomer.

Abstract: A process for the manufacture of ethylene polymers by polymerizing ethylene under high pressures and at high temperatures in the presence of from 0.01 to 0.5 percent by weight of an alkyl ester (alkyl being of 1 to 8 carbon atoms) of an alkenemonocarboxylic acid of 3 or 4 carbon atoms. n-Butyl acrylate is a particularly suitable polymerization activator. Although the start temperature of the ethylene polymerization is relatively low, there is no difference in mechanical and optical properties of a blown film manufactured from the resulting ethylene polymer and of a blown film of pure polyethylene.

Abstract: A process for the high pressure polymerization of ethylene at elevated temperatures in a polymerization zone followed by transfer of the reaction mixture, through a cooling zone, into the separation zone. In this process, the pressure at the cooling zone outlet is periodically reduced briefly, at recurring intervals, these brief pressure reductions being independent of the pressure reductions in the polymerization zone. Using this process, the conversion in the polymerization unit can be increased and a more homogeneous ethylene polymer can be obtained.

Abstract: A process for the manufacture of copolymers of ethylene with tert-butyl acrylate and acrylic acid at from 200.degree. to 350.degree. C under pressures above 800 atmospheres using mean residence times of up to at most 100 seconds, in which the reaction mixture obtained from the polymerization is kept for from 2 to 10 minutes at from 200.degree. to 250.degree. C under a pressure of not more than 500 atmospheres. Terpolymers are obtained which may be used as hot-melt adhesives in the form of thin and extremely homogeneous films.

Abstract: The removal of ethylene from gases which contain the ethylene in a concentration of not more than 1.8% by volume by means of a supported palladium catalyst which contains from 0.05 to 10 g of palladium per liter of an inert inorganic carrier, the oxidation reaction being started at a temperature of from 180.degree. to 200.degree. C.

Abstract: A process for the manufacture of copolymers of ethylene with n-butyl acrylate in a polymerization zone at pressures above 800 atmospheres and at from 150.degree. to 350.degree. C, wherein the reaction mixture obtained is transferred, via a cooling zone which is at a pressure below 500 atmospheres and at from 150.degree. to 250.degree. C, into the high pressure product isolation zone, the mean residence time of the reaction mixture in the two zones being from 2 to 10 minutes. A copolymer which gives good films is obtained.

Abstract: A process for the manufacture of copolymers of ethylene with vinyl acetate at pressures above 800 atmospheres and at from 150.degree. to 350.degree. C, using mean residence times of up to at most 100 seconds. The reaction mixture obtained from the polymerization is kept for from 2 to 10 minutes at from 150.degree. to 250.degree. C under a pressure below 500 atmospheres. Homogeneous ethylene/vinyl acetate copolymers are obtained without the formation of substantial amounts of free acetic acid by decomposition of the vinyl acetate.