CA1280117C - Transition metal catalyst component containing magnesium alkoxy alkoxides - Google Patents

Abstract

TRANSITION METAL CATALYST COMPONENT
CONTAINING MAGNESIUM ALKOXY ALKOXIDES

ABSTRACT OF THE DISCLOSURE
The transition metal component of a Ziegler-Natta type catalyst is prepared by the reaction of a magnesium alkoxy alkoxide with titanium tetrachloride. The transition metal component is combined with an aluminum compound to prepare a catalyst for the polymerization of olefins.

Description

~280~7 C-81?9 -1-TRANSITION METAL CATALYST COMPONENT
CONTAINING MAGNESIUM ALKOXY ALKOXIDES

FI~LD OF THE INV~NTION
Thls invention i8 an improved magnesium supported an~onic coordination cataly~t for the polymer~zation of olefins.

BACRGROUND OF THE INVENTION
A great number of anionlc coordination catalyst ~ystem~ are based on the use of titanium based catalyst on a ma~ne~lum chloride support.
A typical catalyst sy~tcm employing magnesium chloride i8 disclosed ln Briti~h Patent 2,111,066 assigne~
to Mlt~ul Petrochemlcal Indu~trle~ ~td.
C-rtaln prlor art ~atent~ teach magneslum compound su~ported Zi-gler-Natta type cataly~ts that do not directly employ ma~neslum chlorlde ln cataly~t preparatlon. In partlcular, U.S. Patent No, 3,644,318 d-~crlb~s a mixed catalyst componont whlch i8 the reaction product of magnesium alcoholates with tetravalent halo~enated titanium compounds.
Other prior art patents using alkoxides as a ma~nesium source for formation of an olefin polymerlzat~on catalyst are U.S. Patent Nos. 4,144,390; 4,277,372;
4,460,701; ~,48S,186; 4, 497,905, and U.S. Rel~sue Patent 31,099.
It 18 the discovery of U.S. Patent No.
4,837,190, that highly organic solvent soluble alcoholates of magne~ium can be prepared lf magnesium is reacted with alkoxy alcohols. ~he re~ultant alkoxy alcohol derivates of magnesium are readily soluble ln ~'i ~~
A

lZ80~17 organic solvents such as hexane, heptane, toluene, xylene, and etc.
The prior art does not recognize the advantageous use of highly organic solvent soluble alkoxy alkoxides of magnesium. Moreover, the prior art generally employs halogenating agents other than the transition metal halides which are normally part of the polymerization catalyst.
It i~ desirable to develop new anionic coordination catalyst systems having novel sources of magnesium to serve as support for titanium-based catalysts.

SUMMARY OF THE INVENTION
This invention is an anionic coordination catalyst component formed from the reaction of an alkoxy alkoxide of magnesium with titanium tetrachloride. Moreover, this invention i~ an anlonic coordination cataly~t suitable for the polymerlzation of oleflns, whlch catalyst 1~ prepared by comblnlny ~) the reaction product of an alkoxy alkoxlde magneslum compound and titanium tetrachloride with (ii) an organoaluminum compound.

DETAILED DESCRIPTION OF THE INVENTION
The Ziegler-Natta type anionic coordination catalysts are generally prepared by combining a transition metal component with an aluminum co-catalyst. It is particularly desirable to first form the titanium catalyst component and then combine it with the aluminum co-catalyst ~ust prior to the time of actual use. This invention enables the formation of a first transition metal catalyst component from the combination of titanium tetrahalide and a magnesium alkoxy alkoxide without the presence of aluminum co-catalyst or an extra halogenating agent ingredient.

~280~7 C-81~9 -3-The catalyst system of the ~nvention uses a magnesium-containing support for a titanium-containing cataly~t component. The magnesium support is created by the reactlon of a magneslum alkoxy alkoxlde wlth titanium tetrachlorlde.
The magnesium alkoxyalkoxide catalyst components suitable for use ln the process and formation of catalyst of - thls invention are described ln U.S. Patent No. 4,837,190. Suitable magnesium alkoxides as those represented by the formula:

(z-(cH2)n~)-Mg-(o(cH2)m OR2) wherein n and m are the same or different positive integers from 1 to 12; Z is (Rlo)- or (Rl)-; and Rl and R2 are the ~ame or dlfferent hydroearbon radicals eontaining I to 20 carbon atoms. A yreferred ma~ne~ium alkoxide ha8 Rl and R2 alkyl ~roup~ of 1 to 12 earbon atoms, and intoger values of n and ~ ~aeh lo~ than or egual to 4.
~xemplary ~agnesium alkoxy alkoxldes are as follows:

Ma~nesium bis(2-methoxyethylate) Magne~ium bi~(2-ethoxyethylate) Ma~nesium b~s(2-butyoxyethylate) Magnesium bis(3-methoxypropylate) Magneslum bi~(3-ethoxypropylate) Magnesium bis(3-propoxypropylate) Magnesium bis(3-methoxybutylate) The alkoxy alkoxides of magne~lum used in the eatalyst preparation of the invention are prepared by the direet reaetion of metallie magnesium with one or more alkoxy alcohol~. A eatalyst such a~ lodine or mereurie chloride may be u~ed to promote the alkoxlde ~ormlng reaetion. The defining eharaeter~stie of an alkoxy alkoxide belng "organie solvent soluble" is defined herein to be a rA~

~7 solubility of at least 15 weight percent at ambient (approx.
20C) temperature in toluene or 2-methoxyethanol or 2-butoxybutanol.
The transition metal polymerization cataly~t component i8 formed by the reaction of (i) the magnesium alkoxy alkoxide with, (ii) titanium tetrachloride. The molar proportions of magnesium alkoxide (i) to titanium halide (ii) are from 1:5 to 1:1000, with ratios of from l:10 to 1:300 being preferred, Generally, the magnesium and titanium reactants are combined at above ambient temperatures, typically, from about 40C to about 150C.
Reaction time is not critical, but often requires several hours. The product of the first ~tep catalyst component format$on has the appearance of a dark powder, and typically contains from 0.5 to 10% titanium.
The firqt step tltanium catalyst product may be stored under inert condltion~ before comblnation wlth lts co-catalyst ingrodlent.
A suitable aluminum co-catalyst lngredlent is ~elected from alumlnum alkyls, aluminum halides and/or alumlnum organo halides. The aluminum component may be represented by the formula:

( )(3-n)AlXn wherein R 18 an organo group and X is a halogen selected from chlorine, bromine, or iodine and n is zero or an integer from 1 to 2. The mole ratio of titanium tetrahalide to alumlnum component in the combined catalyst ~ystem is from about 1:5 to about 1:500. The transition metal catalyst component and the aluminum co-catalyst component are comblned slmply by mixing, although the components may be milled together if desired.
A wide variety of catalyst addition agents, including activators and electron donors, may be used together with ~2801i7 C-81~9 -5-the essential magnesium alkoxy alkoxide, titanium tetrachlorlde, and aluminum catalyst components.
It i8 prefera~le to add the aluminum co-catalyst component to the titanium component ~ust prior to the use of the catalyst for polymerization.
Catalyst adjuvants such as electron donors are useful in increasing the efficiency of the catalyst of the invention. Typical electron donors are selected from the group consisting of monocarboxylic acid esters, aliphatic carboxylic acids, carboxylic acid anhydrides, ketones, aliphatic ethers and organo silicon compounds. Illustrative electron donors are phthalic anhydride, diisobutylphthalate, phenyltriethoxysilane and diphenyldimethoxysilane. In particular, aromatic polycarboxylic acid esters such as:
monoethyl phthalate, dimethyl phthalate, methylethyl phthalate, monoisobutyl phthalate, diethyl phthalate, ethyl isobutylphthalate, di-n-propyl phthalate, diisopropyl phthalate, dl-n-butyl phthalate, diisobutyl phthalate, di-n-heptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, dineopentyl phthalate, didecyl phthalate, benzyl butyl phthalate, diphenyl phthalate, diethyl naphthalenedicarboxylate and dibutyl naphthalenedicarboxylate are useful as ad~uvants.
Polymerization of olefins is accomplished by contacting the olefin with the polymerization catalyst of the invention in a liquid reaction medium. The liquid reaction medium is typically selected from liquid propylene, heptane, hexane, benzene, toluene, or mixtures thereof. The polymerization conditions are not generally critical, The polymerizatlon is conducted in liquid phase (solution or suspension) at temperatures from about 0C to the boiling point of the liquid phase. Generally, temperatures ln the range of 15C to 150C are suitable. The pressure may be subatmospheric, ambient, or superatmospheric. In addition, hydrogen gas may be used at moderate pressure~ to control the molecular weight of the reaction products.

The catalyst of the invention is useful for the polymerization of ethylene, alpha olefins or mixtures thereof. The polymerization of propylene is particularly desirable using the cataly~t of the invention.
The practlce of the invention i8 illustrated by but not limited to the following Example:

~zao~l7 EXAMPLE
_ ,Part A - Pre~aration of dit2-butoxYethoxY)maanesium (DBEM) 125 milllliters of 2-butoxyethanol and 250 grams of heptane were placed in a flask, and brought to reflux.
Magnesium metal (12.9 grams) was added in ~mall ali~uots to control the vigorous evolution of hydrogen. The mixture was refluxed for 1 hour after the addition of the final aliquot of magnesium. The colorless mixture was filtered to remove a small amount of a black precipitate, yielding 313 grams of magnesium alkoxide solution.

Part B - Pre~aration of catalYst 29.4 grams of the solution of Part A were used having a total content of 10.3 grams of DBEM. 35 ml. of decane and 2.1 grams of phthalic anhydride were added to the DBEM
solution, Thl~ solut~on wa~ added dropwlse to 200 ml. of titanium tetrachlorlde ma~nta~ned at -20C. The dropwise addition wa~ conducted for 45 minute~ then when complete the reaction mlxture was heated to 110C over a period of 3 hours. Upon reaching a temperature of 110C, 2.9 grams of di-isobutylphthalate were added. The mlxture wa~ maintained at 110C and stirred at 350 rpm for 2.5 hourn. The mixture was filtered at 110C to yield a solid powder.
The solid resulting from the reaction was mixed with 2~5 ml. of titanium tetrachloride and heated at 110C for 2 hours. Then 200 ml. of toluene were added and the mixture heated to 110C for 40 minutes. The mixture was filtered at 110C and the solids washed three times with hexane and vacuum dried. Yield was 6.2 grams of gray-black powder containing 6.55% titanium.

Part C - Pol~merization of ~ro~Ylene The catalyst prepared in Part B was tested in a propylene polymerization test. 150 mg. of catalyst, 10 millimoles of triethyl aluminum, and 0.5 millimoles diphenyl dimethoxy silane were added to a 4.5 liter autoclave containing 2 liter~ of hexane. Hydrogen gas at 2 psig.
(13790 pascal) was added, and the reactor pressurized to 100 psig. (689500 pascal) with propylene and maintained at 70C
while stirring at 400 rpm. After 2 hours, the contents were discharged. The yield was 1360 grams of polypropylene per gram of catalyst. The polymer had an isotactic index of 94.8%.

Claims (3)

1. A process for forming a transition metal polymerization catalyst component comprising reacting (i) a soluble magnesium alkoxy alkoxide, solubilized in organic solvent, represented by the formula:
(z-(CH2)n-O)-Mg-(O-(CH2)m-OR2) wherein n and m are the same or different positive integers from 1 to 12; Z is (R1O)- or (R1)-, and R1 and R2 are the same or different hydrocarbon radicals containing 1 to 20 carbon atoms; with (ii) titanium tetrachloride, wherein the mole ratio of (i) to (ii) is from 1:5 to 1:1000.

2. The process of Claim 1 wherein R1 and R2 are alkyl groups of 1 to 12 carbon atoms and n and m are each numbers less than or equal to 4.

3, The process of Claim 1 wherein the magnesium alkoxy alkoxide is selected from the group consisting of:
magnesium bis(2-methoxyethylate) magnesium bis(2-ethoxyethylate) magnesium bis(2-butoxyethylate) magnesium bis(3-methoxypropylate) magnesium bis(3-ethoxypropylate) magnesium bis(3-propoxypropylate) magnesium bis(3-methoxybutylate).