Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Patent
1996-12-18
1997-12-09
Wu, David W.
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
502126, 502133, 502134, 5261252, 5261257, C08F 464
Patent
active
056960441
DESCRIPTION:
BRIEF SUMMARY
The invention relates to methods of producing catalysts for the polymerization of ethylene and copolymerization of ethylene with .delta.-olefins, more specifically to deposited catalysts comprising a transition metal compound based on magnesium-containing carrier.
THE PRIOR ART
There is known a method of producing deposited ethylene polymerization catalysts comprising a transition metal compound (TICl.sub.4, VCl.sub.4, VOCl.sub.3 on a carrier of the formula: Mg.sub.m Cl.sub.n C.sub.p Hg (m=0.80-0.95, n=1.60-1.90, p=0.8-1.6, g=1.4-3.4) (SU 726702 A; SU 1400657 A) by depositing transition metal compounds onto the carrier. In doing so, a carrier is formed by reacting metallic magnesium powder with alkyl chloride in a hydrocarbon medium at a RCl/Mg molar ratio greater than 2.
The main disadvantage of catalysts produced by this method is an uncontrollable granulometric composition of a catalyst powder having a wide catalyst particle size distribution varying from 1 to 100 microns.
As polymerization occurs, a polymer powder having a wide particle size distribution and relatively low bulk density (0.22-0.30 g/cm.sup.3) is formed on such a catalyst.
It is known from the prior art that substantial improvement in the method performance can be achieved by producing a polymer powder having narrow particle size distribution and greater bulk density. To this end, polymerization catalysts having narrow particle size distribution and improved morphology are used. In this case, different polymerization technologies and different polymer application require catalysts having different particle size, e.g. 10-25 microns for suspension polymerization of ethylene and 25-50 microns for gas phase polymerization.
A catalyst having narrow particle size distribution comprising magnesium chloride as the carrier can be produced by reaction of a MgCl.sub.2.3-i-C.sub.8 H.sub.17 OH compound solution in a hydrocarbon diluent with TiCl.sub.4 in the presence of an electron donor compound such as ethyl benzoate, ethyl anizate, and the like (see Japanese Application No. 59153511). The catalyst thus produced has a particle size of 5-15 microns and has rather high activity (up to 35 kg/PE g per Ti.h.atm C.sub.2 H.sub.4) and allows one to produce polyethylene powder having narrow granulometry and high bulk density.
The method of producing a catalyst is disadvantageous in that it is carried out at low temperatures (up to minus 20.degree. C.), large amounts of liquid TiCl.sub.4 are used as a reaction medium and a considerable amount of hydrogen chloride liberate during synthesis of the catalyst. Besides, this method is used to produce catalysts having a particle size of greater than 15 microns.
There is known a method for the preparation of a catalyst by reaction of a (RMgR'.nAlR"mD) with chlorohydrocarbon and by subsequent reaction of the resulting solid product (carrier) with titanium or vanadium halide (see FRG Patent N 326060 and French Patent N 2529207). The RMgR' organomagnesium compound includes (n-Bu) Mg(i-Bu) or (n-Bu)Mg(Oct) compounds soluble in hydrocarbons, and the chlorohydrocarbon compound is preferably tert-BuCl.
The main disadvantage of the catalysts prepared by this method is that they are not sufficiently active.
DISCLOSURE OF THE INVENTION
The object of the claimed invention is to develop a method of producing catalysts for the polymerization of ethylene and copolymerization of ethylene with .delta.-olefins. This method makes it possible to produce polymers having narrow and controllable particle size distribution and greater bulk density and retaining high activity during suspension and gas phase polymerization of ethylene and copolymerization of ethylene with .delta.-olefins.
This object can be attained by using the Mg(C.sub.6 H.sub.5).sub.2 nMgCl.sub.2 mR.sub.2 O organomagnesium compound (wherein C.sub.6 H.sub.5 is phenyl, n=0.37, m.gtoreq.2, R.sub.2 O is ether, preferably dibutyl or diisoamyl ether) to prepare a magnesium-containing carrier for these catalysts. An organomagnesium compound is prepared by reacting magnesi
REFERENCES:
patent: 4439541 (1984-03-01), Takitani et al.
patent: 5132261 (1992-07-01), Murata et al.
Kokai Tokkyo Koho Sep. 1982.
Echevskaya Ljudmila Gennadievna
Khmelinskaya Angelina Dmitrievna
Makhtarulin Sergei Iyanovich
Mikenas Tatyana Borisovna
Nikitin Valentin Evgenievich
Institut Kataliza Iment G.K. Boreskova Sibirskogo Otdelenia Ross
Wu David W.
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