| 摘要 |
A process for continuously producing copolymer comprising moieties derived from ethylene and an alpha -olefin in the presence of a metallocene catalyst system, said process comprising continuously supplying into a liquid-phase reaction zone a feed of ethylene, a feed of liquefied alpha -olefin, a feed of diluent, a feed of metallocene catalyst system, and continuously drawing out a reactor effluent produced thereby; and in accordance with a procedure comprising (a) setting the rate of metallocene system feed to a fixed molar rate; (b) introducing said ethylene feed at a fixed rate as required to produce the desired molar quantity of copolymer product per unit time; (c) setting the total rate of all feeds and the volume of said liquid-phase reaction zone to a fixed residence time, said residence no less than the minimum required to substantially eliminate molecular ethylene from said effluent; (d) performing an isokathic adjustment of the ethylene/ alpha -olefin ratio of said feeds so as to produce product containing the desired ratio of ethylene to alpha -olefin moieties; and (e) adjusting the reaction zone temperature so as to produce copolymer of the desired molecular weight. The process of the invention described herein is particularly suited to in-line analysis of molecular weight and composition by virtue of the relationship - DIFFERENTIAL [E]/ DIFFERENTIAL t=[Ef] tau -1 wherein - DIFFERENTIAL [E]/ DIFFERENTIAL t is the total rate at which ethylene concentration vanishes from said reaction zone by reason of incorporation into said copolymer product, [Ef] is the concentration of ethylene in the total feed, and tau -1 is the inverse of said residence time.
|
