GB824312A - Ethylene polymerisation - Google Patents

Abstract

Ethylene is polymerized under super-atmospheric pressure and within a temperature range of 0-100 DEG C. in the presence of a catalyst comprising a mixture of a peroxy compound and an organic nitrogenous base in whose molecule the nitrogen atoms are not bonded directly to hydrogen atoms. Peroxy compounds include, di-t-butyl, lauroyl and benzoyl peroxides, di-isopropyl peroxydicarbonate, t-butyl perbenzoate, peracetic acid and cyclohexanone peroxide, and the nitrogen compounds may be tertiary amines, e.g. dimethylaniline; N-substituted heterocyclic secondary amines, e.g. N-ethyl piperidine, N-phenyl piperidine and N - methyl - 1,2,5,6 - tetrahydropyridine; N - alkyl pyrrolidines, N - alkyl hexamethylene imines and the corresponding N-alkenyl compounds; and tetrazenes, e.g. tetramethyltetrazene - 2, 1,4 - bis - cyclopentamethylene tetrazene - 2 and N,N1 - azomorpholine. A pressure range of between 200 and 2000 atmospheres preferably between 1000 and 1500 may be used and the ratio of peroxy to nitrogen compound in the mixture is preferably between 1 to 10 and 10 to 1 molar. A chain transfer agent, e.g. hydrogen, carbontetrachloride and chloroform may be present and the reaction may be in an inert liquid medium, e.g. benzene or water or a mixture thereof or in bulk except for an amount of solvent, e.g. white spirit, sufficient to dissolve the catalyst. In examples mixtures of benzoyl, lauroyl and diisopropyl peroxydicarbonate with dimethyl aniline; lauroyl peroxide and tetraethyl tetrazene-2; benzoyl and lauroyl peroxide with 1,4-bis-cyclopentamethylene tetrazene-2; lauroyl peroxide with 1,4-bis-(2-3-decahydrocyclopentamethylene) tetrazene-2; benzoyl and lauroyl peroxide with N-ethyl piperidine; lauroyl peroxide with N-methyl 1,2,5,6-tetrahydropyridine; and di-t-butyl peroxydicarbonate with 1,4-bis-cyclopentamethylene tetrazene-2 are used to produce solid polyethylene in improved yield.