GB1010847A - Polymerisation of ethylene under high pressure - Google Patents

Abstract

Ethylene is polymerized in tubular reactors at 1000-4000 atm and 150-350 DEG C. while feeding ethylene and oxygen at a plurality of successive points into the reactor wherein a flow rate of at least 2.5 m./sec. is maintained, cold oxygen-free ethylene is fed into the reactor at at least one point where the reaction mixture is at more than 250 DEG C., and oxygen, optionally dissolved in a solvent, is fed to the reaction mixture separately from the ethylene, at one or more points immediately adjacent each meeting point of cold ethylene with the reaction mixture, or at one or more points beyond each such meeting point in the direction of flow of the reaction mixture where the mixture is still above 170 DEG C., in such a way that the oxygen concentration at the oxygen feed point(s) is 10-3-10-1% with reference to the total ethylene present in the reactor at the corresponding oxygen feed point(s). The oxygen may be dissolved in water, alkanols, hydrocarbons or substituted hydrocarbons. The unreacted ethylene may be recycled. The polyethylene may be used to form shaped articles and films.