U.S. patent application number 14/184973 was filed with the patent office on 2014-06-19 for olefin polymerisation catalyst containing a cycloakane dicarboxylate as electron donor.
This patent application is currently assigned to INEOS USA LLC. The applicant listed for this patent is INEOS USA LLC. Invention is credited to Andreas B. Ernst, Wallace L. Oliver, Jerome A. Streeky.
Application Number | 20140171294 14/184973 |
Document ID | / |
Family ID | 33131702 |
Filed Date | 2014-06-19 |
United States Patent
Application |
20140171294 |
Kind Code |
A1 |
Ernst; Andreas B. ; et
al. |
June 19, 2014 |
Olefin Polymerisation Catalyst Containing a Cycloakane
Dicarboxylate as Electron Donor
Abstract
A catalyst system useful in polymerizing olefins comprising a
solid, hydrocarbon-insoluble catalyst component containing
magnesium, titanium and halogen and an internal or external
electron donor comprising a substituted hydrocarbyl four to
eight-membered cycloalkane dicarboxylate wherein the substituents
are positioned on the cycloalkane to place the dicarboxylate groups
into adjacent conformational positions and wherein the substitutes
contain 1 to 20 carbon atoms and may be joined to the cycloalkane
structure to form a bicyclo structure.
Inventors: |
Ernst; Andreas B.; (South
Elgin, IL) ; Streeky; Jerome A.; (Bolingbrook,
IL) ; Oliver; Wallace L.; (Wilmette, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INEOS USA LLC |
Lisle |
IL |
US |
|
|
Assignee: |
INEOS USA LLC
Lisle
IL
|
Family ID: |
33131702 |
Appl. No.: |
14/184973 |
Filed: |
February 20, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10548819 |
Jul 16, 2007 |
8716514 |
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PCT/US2004/008888 |
Mar 24, 2004 |
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14184973 |
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60457657 |
Mar 26, 2003 |
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Current U.S.
Class: |
502/125 |
Current CPC
Class: |
C08F 110/06 20130101;
C08F 4/58 20130101; C08F 10/00 20130101; C08F 10/00 20130101; C08F
110/06 20130101; C08F 4/651 20130101; C08F 10/00 20130101; C08F
2500/15 20130101; C08F 2500/18 20130101; C08F 2500/12 20130101;
C08F 4/6494 20130101 |
Class at
Publication: |
502/125 |
International
Class: |
C08F 4/58 20060101
C08F004/58 |
Claims
1. A solid, hydrocarbon-insoluble, catalyst component containing
magnesium, titanium, and halogen further containing an internal
electron donor comprising a substituted hydrocarbyl 4-8 membered
cycloalkane dicarboxylate wherein the substituents are positioned
on the cycloalkane to place the dicarboxylate groups into
conformational proximity positions and wherein the substituents
contain 1 to 20 carbon atoms and may be joined to the cycloalkane
structure to form a bicyclo structure.
2. The catalyst component of claim 1 wherein the internal electron
donor is ##STR00023## in which one X and one Y are carboxylate
(CO.sub.2R) groups, wherein R is selected from lower alkyl groups
containing 1 to 20 carbon atoms; R1-R8 are selected from bulky and
non-bulky alkyl or substituted alkyl groups to produce a ring
conformation that places the carboxylate groups into proximity; and
remaining the X and Y groups are selected from hydrogen and methyl,
and provided two of the R1-R8 groups may be connected to form a
bicyclo structure.
3. The catalyst component of claim 1 wherein the internal electron
donor is ##STR00024## wherein R is selected from lower alkyl groups
containing 1 to 20 carbon atoms, R1 and R4 are selected from bulky
groups sufficient to place the carboxyl groups into conformational
proximity positions, and R2 and R4 are selected from hydrogen and
methyl.
4. The catalyst component of claim 1 wherein the internal electron
donor is trans-di-n-butyl-4,5-di-isopropylcyclohexane
trans-dicarboxylate or trans-diisopropyl 4,5-di-t-butylcyclohexane
trans-dicarboxylate.
5. The catalyst component of claim 1 wherein the internal electron
donor is ##STR00025## wherein R is selected from lower alkyl groups
containing 1 to 20 carbon atoms, R1, R3, and R6 are selected from
bulky groups sufficient to place the carboxyl groups into
conformational proximity positions, and R2, R4, and R5 are selected
from hydrogen and methyl.
6. The catalyst component of claim 1 wherein the internal electron
donor is ##STR00026## wherein R is selected from lower alkyl groups
containing 1 to 20 carbon atoms.
7. The catalyst component of claim 1 wherein the internal electron
donor is ##STR00027## wherein R is selected from lower alkyl groups
containing 1 to 20 carbon atoms.
8. The catalyst component of claim 1 wherein R is ethyl, propyl,
isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl,
isopentyl, hexyl, 2-ethylhexyl, or octyl.
9. The catalyst component of claim 1 wherein R contains 3 to 8
carbon atoms.
10. The catalyst component of claim 1 wherein R is ethyl, propyl,
isopropyl, n-butyl, isobutyl, or s-butyl.
11. The catalyst component of claim 1 at least one bulky
substituent group contains 3 to 20 carbon atoms.
12. The catalyst component of claim 1 at least one of isopropyl,
isobutyl, t-butyl, s-butyl, isopentyl, isohexyl, or
2-ethylhexyl.
13. The catalyst component of claim 1 at least one of isopropyl,
isobutyl, t-butyl, or s-butyl.
14. The catalyst component of claim 1 at least one bulky
substituent group contains a hetero atom.
15. A olefin polymerization catalyst system comprising a solid,
hydrocarbon insoluble component containing magnesium, titanium, and
halogen and an internal electron donor compound, an aluminum alkyl
compound, and an external electron donor compound comprising a
substituted hydrocarbyl 4-8 membered cycloalkane dicarboxylate
wherein the substituents are positioned on the cycloalkane to place
the dicarboxylate groups into conformational proximity positions
and wherein the substitutes contain 1 to 20 carbon atoms and may be
joined to the cycloalkane structure to form a bicyclo structure.
Description
FIELD OF THE INVENTION
[0001] This invention relates to components useful in propylene
polymerization catalysts, and particularly relates to electron
donor components used in combination with magnesium-containing
supported titanium-containing catalyst components.
BACKGROUND OF THE INVENTION
[0002] Use of solid, transition metal-based, olefin polymerization
catalyst components is well known in the art including such solid
components supported on a metal oxide, halide or other salt such as
widely-described magnesium-containing, titanium halide-based
catalyst components. Such catalyst components are referred to as
"supported." Although many polymerization and copolymerization
processes and catalyst systems have been described for polymerizing
or copolymerizing alpha-olefins, it is advantageous to tailor a
process and catalyst system to obtain a specific set of properties
of a resulting polymer or copolymer product. For example, in
certain applications, a combination of high activity,
stereospecificity are required together with polymer
characteristics such as good morphology, desired particle size
distribution, acceptable bulk density, molecular weight
distribution, and the like.
[0003] Typically, supported catalyst components useful for
polymerizing propylene and higher alpha-olefins as well as for
polymerizing propylene and higher olefins with a minor amounts of
ethylene and other alpha-olefins contain an electron donor
component as an internal modifier. Such internal modifier is an
integral part of the solid supported component as is distinguished
from an external electron donor component, which together with an
aluminum alkyl component, comprises the catalyst system. Typically,
the external modifier and aluminum alkyl are combined with the
solid supported component shortly before the combination is
contacted with an olefin monomer.
[0004] Selection of the internal modifier can affect catalyst
performance and the resulting polymer formed from a catalyst
system. As stated above, it is advantageous and an advance in the
art to discover internal modifiers including combinations of
modifiers which, when incorporated into a supported catalyst,
produce desired effects on the polymerization process and the
polymer produced.
[0005] Generally, organic electron donors have been described as
useful in preparation of the stereospecific supported catalyst
components including organic compounds containing oxygen, nitrogen,
sulfur, and/or phosphorus. Such compounds include organic acids,
organic acid anhydrides, organic acid esters, alcohols, ethers,
aldehydes, ketones, amines, amine oxides, amides, thiols, various
phosphorus acid esters and amides, and the like. Mixtures of
organic electron donors have been described as useful in
incorporating into supported catalyst components. Examples of
organic electron donors include dicarboxy esters such as alkyl
phthalate and succinate esters.
[0006] Examples of substituted succinate ester and cyclohexane
dicarboxylate electron donors are described in U.S. Pat. Nos.
4,442,276 and 4,952,649, European Published Application 86,288, and
PCT Published Application WO 00/63261, all incorporated by
reference herein.
[0007] Numerous individual processes or process steps have been
disclosed to produce improved supported, magnesium-containing,
titanium-containing, electron donor-containing olefin
polymerization or copolymerization catalysts. For example,
Arzoumanidis et al., U.S. Pat. No. 4,866,022, incorporated by
reference herein, discloses a method for forming an advantageous
alpha-olefin polymerization or copolymerization catalyst or
catalyst component which involves a specific sequence of specific
individual process steps such that the resulting catalyst or
catalyst component has exceptionally high activity and
stereospecificity combined with very good morphology. A solid
hydrocarbon-insoluble, alpha-olefin polymerization or
copolymerization catalyst or catalyst component with superior
activity, stereospecificity and morphology characteristics is
disclosed as comprising the product formed by 1) forming a solution
of a magnesium-containing species from a magnesium hydrocarbyl
carbonate or magnesium carboxylate; 2) precipitating solid
particles from such magnesium-containing solution by treatment with
a transition metal halide and an organosilane; 3) reprecipitating
such solid particles from a mixture containing a cyclic ether; and
4) treating the reprecipitated particles with a transition metal
compound and an electron donor.
[0008] Arzoumanidis et al., U.S. Pat. No. 4,540,679, incorporated
by reference herein, discloses a process for the preparation of a
magnesium hydrocarbyl carbonate by reacting a suspension of a
magnesium alcoholate in an alcohol with carbon dioxide and reacting
the magnesium hydrocarbyl carbonate with a transition metal
component.
[0009] Arzoumanidis et al., U.S. Pat. No. 4,612,299, incorporated
by reference herein, discloses a process for the preparation of a
magnesium carboxylate by reacting a solution of a hydrocarbyl
magnesium compound with carbon dioxide to precipitate a magnesium
carboxylate and reacting the magnesium carboxylate with a
transition metal component.
[0010] Particular uses of propylene polymers depend upon the
physical properties of the polymer, such as molecular weight,
viscosity, stiffness, flexural modulus, and polydispersity index
(molecular weight distribution (M.sub.w/M.sub.n)). In addition,
polymer or copolymer morphology often is critical and typically
depends upon catalyst morphology. Good polymer morphology generally
involves uniformity of particle size and shape, resistance to
attrition and an acceptably high bulk density. Minimization of very
small particles (fines) typically is important especially in
gas-phase polymerizations or copolymerizations in order to avoid
transfer or recycle line pluggage. A particularly advantageous
polymer for certain uses would have a broadened polydispersity
index, preferably above about 5, more preferably above about 6, and
may be above 7, while maintaining an acceptable flexural modulus,
preferably above about 1800, more preferably above about 2000 MPa,
and may be above 2400 MPa.
SUMMARY OF THE INVENTION
[0011] A solid, hydrocarbon-insoluble, catalyst component useful in
polymerizing olefins containing magnesium, titanium, and halogen
further contains an internal electron donor comprising a
substituted hydrocarbyl 4-8 membered cycloalkane' dicarboxylate
wherein the substituents are positioned on the cycloalkane to place
the dicarboxylate groups into conformational proximity positions
and wherein the substitutes contain 1 to 20 carbon atoms and may be
joined to the cycloalkane structure to form a bicyclo
structure.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0012] Supported catalyst components of this invention contain at
least one internal electron donor comprising a substituted
hydrocarbyl 4-8 membered cycloalkane dicarboxylate wherein the
substituents are positioned on the cycloalkane to place the
dicarboxylate groups into conformational proximity positions and
wherein the substitutes contain 1 to 20 carbon atoms and may be
joined to the cycloalkane structure to form a bicyclo
structure.
[0013] Typical electron donor compounds of this invention are alkyl
esters of substituted cycloalkane dicarboxylic acids, in which the
alkyls contain 1 to about 20 carbon atoms. Such alkyls typically
contain at least two and preferably at least three carbon atoms.
Suitable alkyls also may contain up to 12 and, typically, up to 8
carbon atoms. Other suitable alkyls contain from 4 to 6 carbon
atoms. Typical examples of alkyl esters useful in this invention
include ethyl, propyl, isopropyl, n-butyl, isobutyl, s-butyl,
t-butyl, n-pentyl, isopentyl, hexyl, 2-ethylhexyl, and octyl,
esters. Especially suitable alkyls are isopropyl, n-butyl, and
s-butyl.
[0014] Although, typically, the alkyl groups forming alkyl
dicarboxylic acid esters of this invention are the same, the
invention includes alkyl dicarboxylic acid esters having different
alkyl groups.
[0015] In alkyl dicarboxylic acid esters of this invention, the
carboxylate groups are placed in conformational proximity
positions. Preferably, such carboxylate groups are attached to
adjacent carbon atoms forming an alkyl cycloalkane 1,2
dicarboxylate. In another aspect of the invention, such carboxylate
groups may form a cycloalkane 1,3 dicarboxylate and the like where
the carboxylate groups are not on adjacent carbon atoms. In any
case, the conformational structure of the cycloalkane is
constrained by substituent groups (or chemical bonds in the case of
bicyclo structures) such that the carboxylate groups are placed in
conformational proximity positions. A structure is constrained when
bond rotation or ring conformation change is restricted such that a
particular conformation is preferred.
[0016] Substituent groups that are sufficiently bulky to constrain
a ring conformation change typically contain at least 3 carbon
atoms, although groups containing compatible heteroatoms such as
nitrogen, sulfur, silicon, and the like may contain at least one
carbon atom. Typically, such bulky substituent groups contain up to
20 carbon atoms and may contain up to 12 carbon atoms. Typically
suitable bulky substituent groups are isopropyl, isobutyl, t-butyl,
s-butyl, isopentyl, isohexyl, 2-ethylhexyl, and the like. Compounds
of this invention may contain one or more of such bulky substituent
group. Multiple bulky groups may be substituents to produce a
constrained conformational structure.
[0017] Alkyl groups used in this invention also may be substituted
with compatible groups containing heteroatoms including silicon and
halogens.
[0018] Typical examples of these compounds are represented by the
substituted cyclohexane:
##STR00001##
[0019] in which one X and one Y are carboxylate (CO.sub.2R) groups,
wherein R is selected from lower alkyl groups containing 1 to 20
carbon atoms; R.sub.1-R.sub.8 are selected from bulky and non-bulky
alkyl or substituted alkyl groups to produce a ring conformation
that places the carboxylate groups into proximity; and remaining
the X and Y groups are selected from hydrogen and methyl, and
provided two of the R.sub.1-R.sub.8 groups may be connected to form
a bicycio structure.
[0020] Preferably, for non-bicyclo structures, the carboxylate
groups are trans and R.sub.1 and R.sub.4 are selected from bulky
groups. Preferably, the non-bulky groups are hydrogen.
[0021] Other representations of these substituted cyclohexanes
demonstrating conformation of the carboxyl groups is:
##STR00002##
[0022] in which R is selected from lower alkyl groups containing 1
to 20 carbon atoms, at least one of R.sub.1 and R.sub.4 are
selected from bulky groups sufficient to place the carboxyl groups
into conformational proximity positions, and R.sub.2 and R.sub.4
are selected from hydrogen and methyl. The remaining substituents
on such a ring structure usually are hydrogen, but may be other
compatible groups that produce the desired ring conformation.
##STR00003##
[0023] in which R is selected from lower alkyl groups containing 1
to 20 carbon atoms, at least one of R.sub.1, R.sub.3, and R.sub.6
are selected from bulky groups sufficient to place the carboxyl
groups into conformational proximity positions, and R.sub.2,
R.sub.4, and R.sub.5 are selected from hydrogen and methyl. The
remaining substituents on such a ring structure usually are
hydrogen, but may be other compatible groups that produce the
desired ring conformation.
[0024] Representations of bicyclo compounds of this invention
are:
##STR00004##
[0025] A representation of a cyclopentane of this invention is:
##STR00005##
[0026] in which R1 and R2 are selected to place the carboxylate
groups into conformational proximity.
[0027] In one aspect of this invention, carboxylate groups are
positioned onto cycloalkyl structures such that at least two
carboxylate groups are in conformational proximity, i.e. at the
preferred confirmation of the cycloalkyl ring structure, the
carboxylate groups will be spaced close enough to experience van
der Waals repulsion between the groups. Such repulsion typically is
sufficient that would place the ring into another preferred
conformation if the ring conformation was not otherwise
constrained.
[0028] In another aspect of this invention, the carboxylate groups
are spaced at least as proximate as corresponding phthalate
carboxylate groups.
[0029] An example of conformational proximate carboxylate groups
are trans-di-n-butyl-4,5-di-isopropylcyclohexane
trans-dicarboxylate and trans-diisopropyl 4,5-di-t-butylcyclohexane
trans-dicarboxylate:
##STR00006##
[0030] In these structures, spatially bulky tertiary-butyl and
isopropyl groups are in a trans configuration on the cyclohexane
ring, which inhibits ring reversal and produces a preferred
confirmation in which the bulky groups are in the equatorial
positions on the cyclohexane ring. The result is to place the
carboxylate groups in equatorial positions, which are in
conformational proximity.
[0031] Below are summarized general methods which can be used to
prepare the donors which are described. The first method entails
hydrogenation of an appropriately substituted aromatic diacid
followed by esterification. The second method employs first a
Diels-Alder reaction of a substituted diene and maleic anhydride to
form the substituted cyclohexene structure. After hydrogenation and
esterification the substituted cyclic diester is formed. The
bicyclic compounds can be formed by the third route employing a
Diels-Alder reaction of maleic anhydride and a cyclic diene to form
the bicyclic structure. Hydrogenation and esterification would
yield the bicyclic diester. These reactions are known in the
art.
##STR00007##
The routes we are employing to prepare examples of the above are as
follows:
[0032] Cyclohexane anhydride was esterified with ethanol and a
p-toluenesulfonic acid catalyst to yield the cis diester, which was
used as an internal donor to prepare a catalyst according to the
procedures outlined above. The cis diester may be epimierized to
the more thermodynamically stable trans isomer with sodium ethoxide
and ethanol and a catalyst may be prepared as described above.
##STR00008##
In a similar route, the methyl-cyclohexane anhydride also was
esterified as shown below. The product was a mixture of isomers,
which is believed to be predominantly a combination of cis fused
products. That material also was used directly in a catalyst
preparation. Also this may be epimerized and subsequently used in a
catalyst preparation.
##STR00009##
The bicyclic materials may be prepared by first reducing the double
bonds of the purchased anhydrides with n=1 and 2. After
esterification, cis fusion appears again to be preserved and a
catalyst has been prepared from the bicyclo[2.2.1] system. and a
catalyst may be prepared from the bicyclo[2.2.2] system. The
bicyclo[2.2.2] system will need to be treated again with hydrogen
to fully reduce the initial double bond before proceeding. Both
materials will also may be epimerized to the predicted more stable
trans isomers to be used in catalyst preparations.
##STR00010##
[0033] High activity supported (HAC) titanium-containing components
useful in this invention generally are supported on
hydrocarbon-insoluble, magnesium-containing compounds in
combination with an electron donor compound. Such supported
titanium-containing olefin polymerization catalyst component
typically is formed by reacting a titanium (IV) halide, an organic
electron donor compound and a magnesium-containing compound.
Optionally, such supported titanium-containing reaction product may
be further treated or modified by further chemical treatment with
additional electron donor or Lewis acid species.
[0034] Suitable magnesium-containing compounds include magnesium
halides; a reaction product of a magnesium halide such as magnesium
chloride or magnesium bromide with an organic compound, such as an
alcohol or an organic acid ester, or with an organometallic
compound of metals of Groups I-III; magnesium alcoholates; or
magnesium alkyls.
[0035] Examples of supported catalysts are prepared by reacting a
magnesium chloride, alkoxy magnesium chloride or aryloxy magnesium
chloride with a titanium halide, such as titanium tetrachloride,
and further incorporation of an electron donor compound. In a
preferable preparation, the magnesium-containing compound is
dissolved, or is in a slurry, in a compatible liquid medium, such
as a hydrocarbon to produce suitable catalyst component
particles.
[0036] The possible solid catalyst components listed above only are
illustrative of many possible solid, magnesium-containing, titanium
halide-based, hydrocarbon-insoluble catalyst components useful in
this invention and known to the art. This invention is not limited
to a specific supported catalyst component.
[0037] In a typical supported catalyst of this invention, the
titanium to magnesium atom ratio is above about 0.5 to 1 and may
range to about 20 to 1. Greater amounts of titanium may be employed
without adversely affecting catalyst component performance, but
typically there is no need to exceed a titanium to magnesium ratio
of about 20:1. More preferably, the titanium to magnesium ratio
ranges from about 2:1 to about 15:1. The internal electron donor
components typically are incorporated into the solid, supported
catalyst component in a total amount ranging up to about 1 mole per
gram atom of titanium in the titanium compound, and preferably from
about 0.001 to about 0.6 mole per gram atom of titanium in the
titanium compound. Typical amounts of internal donor are at least
0.01 mole per gram atom of titanium, preferably above about 0.05
and typically above about 0.1 mole per gram atom of titanium. Also,
typically, the amount of internal donor is less than 1 mole per
gram atom of titanium, and preferably below about 0.5, and more
preferably below about 0.3 mole per gram atom of titanium.
[0038] The internal electron donor material of this invention is
incorporated into a solid, supported catalyst component during
formation of such component. Typically, such electron donor
material is added with, or in a separate step, during treatment of
a solid magnesium-containing material with a titanium (IV)
compound. Most typically, a solution of titanium tetrachloride and
the internal electron donor modifier material is contacted with a
magnesium-containing material. Such magnesium-containing material
typically is in the form of discrete particles and may contain
other materials such as transition metals and organic
compounds.
[0039] The preferred solid, hydrocarbon-insoluble catalyst or
catalyst component of this invention for the stereoregular
polymerization or copolymerization of alpha-olefins comprises the
product formed by a process, which comprises a first step of
forming a solution of a magnesium-containing species in a liquid
wherein the magnesium-containing species is formed by reacting a
magnesium-containing compound with carbon dioxide or sulfur
dioxide. The magnesium-containing compound from which the
magnesium-containing species is formed is a magnesium alcoholate, a
magnesium hydrocarbyl alcoholate, or a hydrocarbyl magnesium
compound. When carbon dioxide is used, the magnesium-containing
species is a hydrocarbyl carbonate or a carboxylate. When sulfur
dioxide is employed, the resulting magnesium-containing species is
a hydrocarbyl sulfite (ROSO.sub.2.sup.-) or an hydrocarbyl
sulfinate (RSO.sub.2.sup.-).
[0040] Generally, magnesium hydrocarbyl carbonate is prepared by
reacting carbon dioxide with a magnesium alcoholate. For example,
magnesium hydrocarbyl carbonate is formed by suspending magnesium
ethoxide in ethanol and adding carbon dioxide until the magnesium
ethoxide dissolves forming magnesium ethyl carbonate. If, however,
the magnesium ethoxide were suspended in 2-ethylhexanol, magnesium
2-ethylhexyl carbonate, magnesium ethyl carbonate and magnesium
ethyl/2-ethylhexyl carbonate may be formed. If the magnesium
ethoxide is suspended in a liquid hydrocarbon or halohydrocarbon
which is free of alcohol, the addition of carbon dioxide results in
the breaking apart of the magnesium ethoxide particles and the
magnesium hydrocarbyl carbonate reaction product does not dissolve.
The reaction of a magnesium alcoholate with carbon dioxide can be
represented as:
##STR00011##
wherein n is a whole number or fraction up to 2, and wherein R is a
hydrocarbyl group of 1 to 20 carbon atoms. In addition, a magnesium
alcoholate-containing two different aforesaid hydrocarbyl groups
may be employed. From the standpoint of cost and availability,
magnesium alcoholates which are preferred for use according to this
invention are those of the formula Mg(OR).sub.2 wherein R is as
defined below. In terms of catalytic activity and
stereospecificity, best results are achieved through the use of
magnesium alcoholates of the formula Mg(OR').sub.2 wherein R' is an
alkyl radical of 1 to about 8 carbon atoms, an aryl radical of 6 to
about 12 carbon atoms or an alkaryl or aralkyl radical of 7 to
about 12 carbon atoms. Magnesium ethoxide is most preferred.
[0041] Specific examples of magnesium alcoholates that are useful
according to this invention include: Mg(OCH.sub.3).sub.2,
Mg(OC.sub.2H.sub.5).sub.2, Mg(OC.sub.4H.sub.9).sub.2,
Mg(OC.sub.6H.sub.5).sub.2, Mg(OC.sub.6H.sub.13).sub.2,
Mg(OC.sub.9H.sub.19).sub.2, Mg(OC.sub.10H.sub.7).sub.2,
Mg(OC.sub.12H.sub.9).sub.2, Mg(OC.sub.12H.sub.25).sub.2,
Mg(OC.sub.16H.sub.33).sub.2, Mg(OC.sub.18H.sub.37).sub.2,
Mg(OC.sub.20H.sub.41).sub.2, Mg(OCH.sub.3)(OC.sub.2H.sub.5),
Mg(OCH.sub.3)(OC.sub.6H.sub.13),
Mg(OC.sub.2H.sub.5)(OC.sub.8H.sub.17),
Mg(OC.sub.6H.sub.13)(OC.sub.20H.sub.41),
Mg(OC.sub.3H.sub.7)(OC.sub.10H.sub.7), Mg(OC.sub.2H.sub.4Cl).sub.2
and Mg(OC.sub.16H.sub.33)(OC.sub.18H.sub.37). Mixtures of magnesium
alcoholates also may be used if desired.
[0042] A suitable magnesium hydrocarbyl alcoholate has the formula
MgR(OR') wherein R and R' are as defined hereinabove for the
magnesium alcoholate. When alcohol is used as the suspending medium
for the reaction between the magnesium hydrocarbyl alcoholate and
carbon dioxide or sulfur dioxide, the magnesium hydrocarbyl
alcoholate is a functional equivalent of the magnesium alcoholate
because the magnesium hydrocarbyl alcoholate is converted to the
magnesium alcoholate in alcohol. However, when the suspending
medium does not contain alcohol, the magnesium hydrocarbyl
alcoholate reacts with carbon dioxide as:
##STR00012##
wherein y+x=n.gtoreq.2 and y=0 for x=n.ltoreq.1.0. In the case of
y+n=2,
##STR00013##
is the resulting magnesium-containing species.
[0043] When the magnesium compound from which the
magnesium-containing species is formed is a hydrocarbyl magnesium
compound having the formula XMgR, where X is a halogen and R is a
hydrocarbyl group of 1 to 20 carbon atoms, the reaction of the
hydrocarbyl magnesium compound with carbon dioxide forms a
magnesium carboxylate and can be represented as follows:
##STR00014##
If the hydrocarbyl magnesium compound contains two hydrocarbyl
groups, the reaction is represented as:
##STR00015##
where R is as defined for X--MgR.
[0044] The hydrocarbyl magnesium compounds useful in this invention
have the structure R--Mg-Q wherein Q is hydrogen, halogen or R'
(each R' is independently a hydrocarbyl group of 1 to 20 carbon
atoms.) Specific examples of hydrocarbyl magnesium compounds useful
in this invention include: Mg(CH.sub.3).sub.2,
Mg(C.sub.2H.sub.5).sub.2, Mg(C.sub.4H.sub.9).sub.2,
Mg(C.sub.6H.sub.5).sub.2, Mg(C.sub.6H.sub.13).sub.2,
Mg(C.sub.9H.sub.19).sub.2, Mg(C.sub.10H.sub.7).sub.2,
Mg(C.sub.12H.sub.9).sub.2, Mg(C.sub.12H.sub.25).sub.2,
Mg(C.sub.16H.sub.33).sub.2, Mg(C.sub.20H.sub.41).sub.2,
Mg(CH.sub.3)(C.sub.2H.sub.5), Mg(CH.sub.3)(C.sub.6H.sub.13),
Mg(C.sub.2H.sub.5)(C.sub.8H.sub.17),
Mg(C.sub.6H.sub.13)(C.sub.20H.sub.41),
Mg(C.sub.3H.sub.7)(C.sub.10H.sub.7), Mg(C.sub.2H.sub.4Cl).sub.2 and
Mg(C.sub.16H.sub.33)(C.sub.18H.sub.37), Mg(C.sub.2H.sub.5)(H),
Mg(C.sub.2H.sub.5)(Cl), Mg(C.sub.2H.sub.5)(Br), etc. Mixtures of
hydrocarbyl magnesium compounds also can be employed if desired.
From the standpoint of cost and availability, dihydrocarbyl
magnesium compounds preferred for use in this invention are those
of the formula MgR.sub.2 wherein R is as defined above. In terms of
catalytic activity and stereospecificity, best results are achieved
through the use of hydrocarbyl magnesium halide compounds of the
formula MgR'Q' wherein R' is an alkyl radical of 1 to about 18
carbon atoms, an aryl radical of 6 to about 12 carbon atoms or an
alkaryl or aralkyl radical of 7 to about 12 carbon atoms and Q' is
chloride or bromide.
[0045] Most preferably, the magnesium-containing compound is a
magnesium alcoholate, and the resulting magnesium-containing
species is a magnesium hydrocarbyl carbonate.
[0046] For example, a magnesium alcoholate may be used which is
prepared by reacting magnesium metal turnings to completion with a
lower molecular weight alcohol, such as methanol, ethanol, or
1-propanol, with or without a catalyst such as iodine or carbon
tetrachloride, to form a solid magnesium alcoholate. Any excess
alcohol is removed by filtration, evaporation or decantation. Use
as the magnesium-containing compound of a magnesium alcoholate
produced in this manner affords a solution of the
magnesium-containing species which has a substantially reduced
viscosity.
[0047] Diluents or solvents suitable for use in the carbonation of
the magnesium compounds to form the magnesium-containing species
include alcohols containing from 1 to 12 carbon atoms, non-polar
hydrocarbons and halogenated derivatives thereof, ethers and
mixtures thereof that are substantially inert to the reactants
employed and, preferably, are liquid at the temperatures of use. It
also is contemplated to conduct the reaction at elevated pressure
so that lower-boiling solvents and diluents can be used even at
higher temperatures. Examples of useful solvents and diluents
include alcohols such as methanol, ethanol, 1- or 2-propanol,
t-butyl alcohol, benzyl alcohol, the amyl alcohols, 2-ethylhexanol
and branched alcohols containing 9 or 10 carbon atoms; alkanes such
as hexane, cyclohexane, ethylcyclohexane, heptane, octane, nonane,
decane, undecane, and the like; haloalkanes such as
1,1,2-trichloroethane, carbon tetrachloride, and the like;
aromatics such as xylenes and ethylbenzene; and halogenated and
hydrogenated aromatics such as chlorobenzene, o-dichlorobenzene,
tetrahydronaphthalene and decahydronaphthalene.
[0048] The solution of the magnesium-containing species typically
comprises at least one monohydroxy alcohol containing from 2 to
about 18 carbon atoms, preferably at a ratio of the total number of
moles of the at least one alcohol to the number of moles of the
aforesaid magnesium-containing compound in the range of from about
1.45:1, more preferably from about 1.6:1, to about 2.3:1, more
preferably to about 2.1:1. Alcohols that are suitable for use in
the present invention include those having the structure HOR
wherein R is an alkyl radical of 1 to about 18 carbon atoms, an
aryl radical of 6 to about 12 carbon atoms or an alkaryl or aralkyl
radical of 7 to about 12 carbon atoms. Typically, one or more
alcohols containing from 1 to 12 carbon atoms can be used, such as
ethanol, 1- or 2-propanol, t-butyl alcohol, cyclohexanol,
2-ethylhexanol, amyl alcohols including isoamyl alcohol, and
branched alcohols having 9 to 12 carbon atoms. Preferably,
2-ethylhexanol or ethanol is employed.
[0049] In somewhat greater detail, the magnesium-containing species
is prepared by dissolving or suspending the magnesium-containing
compound in a liquid. Approximately 10 to 80 parts by weight of the
magnesium-containing compound is employed per 100 parts by weight
liquid. A sufficient amount of carbon dioxide is bubbled into the
liquid suspension to provide from about 0.1 to 4 moles of carbon
dioxide per mole of the magnesium compound with mild stirring.
Typically, approximately 0.3 to 4 moles of CO.sub.2 are added to
the solution or suspension of the magnesium-containing compound
with stirring at a temperature of about 0 to 100.degree. C. over a
period of approximately 10 minutes to 24 hours.
[0050] Irrespective of which of the aforesaid magnesium-containing
compounds is used to form the magnesium-containing species, solid
particles are precipitated from the aforesaid solution of the
magnesium-containing species by treatment with a transition metal
or Group IV halide and preferably additionally with a morphology
controlling agent. The transition metal or Group IV halide
preferably is a titanium (IV) or silicon halide and more preferably
is titanium tetrachloride. While any convenient conventional
morphology controlling agent can be employed, organosilanes are
particularly suitable for use as the morphology controlling agent.
Suitable organosilanes for this purpose include those having a
formula: R.sub.nSiR'.sub.4-n, wherein n=0 to 4 and wherein R is
hydrogen or an alkyl, alkoxy, haloalkyl or aryl radical containing
one to about ten carbon atoms, or a halosilyl radical or
haloalkylsilyl radical containing one to about eight carbon atoms,
and R' is OR or a halogen. Typically, R is an alkyl or chloroalkyl
radical containing one to about eight carbon atoms and one to about
four chlorine atoms, and R' is chlorine or an --OR radical
containing one to four carbon atoms. A suitable organosilane may
contain different R' groups. Mixtures of organosilanes may be used.
Preferable organosilanes include tri-methyichlorosilane,
trimethylethoxysilane, dimethyldichiorosilane, tetraethoxy-silane,
and hexamethyldisiloxane.
[0051] Broadly, in accordance with this invention, the precipitated
particles are treated with a transition metal compound and an
electron donor. Suitable transition metal compounds which can be
used for this purpose include compounds represented by the formula
T.sub.aY.sub.bX.sub.c-b wherein T.sub.a is a transition metal
selected from Groups IV-B, V-B and VI-B of the Periodic Table of
Elements, Y is oxygen, OR' or NR'.sub.2; wherein each R' is
independently hydrogen or hydrocarbyl group of 1 to 20 carbon
atoms; X is halogen, preferably chlorine or bromine; c has a value
corresponding to the valence of the transition metal, T.sub.a; b
has a value of from 0 to 5 with a value of c-b being from at least
1 up to the value of the valence state of the transition metal
T.sub.a. Suitable transition metal compounds include halide
compounds of titanium, zirconium, vanadium and chromium, such as
chromyl chloride, vanadium oxytrichloride, zirconium tetrachloride,
vanadium tetrachloride, and the like.
[0052] In addition to supported catalyst components formed from
magnesium alcoholates or magnesium hydrocarbyl carbonates as
described above, other magnesium-containing supported components
may be produced by reacting titanium halide-containing compounds
with magnesium halides, such as magnesium chloride, magnesium
oxyhalides, magnesium alkoxides, and the like. In preparation of
suitable supported catalysts useful for olefin polymerization, an
electron donor material is added during formation of such component
in which a magnesium compound is reacted with a titanium
halide-containing compound as described in the art. Irrespective of
the method of formation, the supported catalyst components of this
invention include the internal electron donor material described in
this invention.
[0053] Titanium (IV) compounds useful in preparation of the
catalyst or catalyst component of this invention are titanium
halides and haloalcoholates having 1 to about 20 carbon atoms per
alcoholate group such as methoxy, ethoxy, butoxy, hexoxy, phenoxy,
decoxy, naphthoxy, dodecoxy and eicosoxy. Mixtures of titanium
compounds can be employed if desired. Preferred titanium compounds
are the halides and haloalcoholates having 1 to 8 carbon atoms per
alcoholate group. Examples of such compounds include TiCl.sub.4,
TiBr.sub.4, Ti(OCH.sub.3)Cl.sub.3, Ti(OC.sub.2H.sub.5)Cl.sub.3,
Ti(OC.sub.4H.sub.9)Cl.sub.3, Ti(OC.sub.6H.sub.5)Cl.sub.3,
Ti(OC.sub.6H.sub.13)Br.sub.3, Ti(OC.sub.8H.sub.17)Cl.sub.3,
Ti(OCH.sub.3).sub.2Br.sub.2, Ti(OC.sub.2H.sub.5).sub.2Cl.sub.2,
Ti(OC.sub.6H.sub.13).sub.2Cl.sub.2,
Ti(OC.sub.8H.sub.17).sub.2Br.sub.2, Ti(OCH.sub.3).sub.3Br,
Ti(OC.sub.2H.sub.5).sub.3Cl, Ti(OC.sub.4H.sub.9).sub.3Cl,
Ti(OC.sub.6H.sub.13).sub.3Br, and Ti(OC.sub.8H.sub.17).sub.3Cl.
Titanium tetrahalides and particularly TiCl.sub.4 are most
preferred from the standpoint of attaining maximum activity and
stereospecificity.
[0054] The particles formed as described above, the titanium halide
component, and the electron donor components described in this
invention are reacted at temperatures ranging from about
-10.degree. C. to about 170.degree. C., generally over a period of
several minutes to several hours, and are contacted in amounts such
that the atomic ratio of titanium to magnesium components in the
reaction mixture (calculated as magnesium in magnesium compound
from which the magnesium-containing species is formed) is at least
about 0.5:1. Preferably, this ratio ranges from about 0.5:1 to
about 20:1. Greater amounts of titanium may be employed without
adversely affecting catalyst component performance, but typically
there is no need to exceed a titanium to magnesium ratio of about
20:1. More preferably, the titanium to magnesium ratio ranges from
about 2:1 to about 15:1 to ensure that the catalyst components
contain sufficient titanium to exhibit good activities without
being wasteful of the titanium compound employed in preparation.
The internal electron donor components are employed in a total
amount ranging up to about 1.0 mole per gram atom of titanium in
the titanium compound, and preferably from about 0.001 to about 0.6
mole per gram atom of titanium in the titanium compound. Best
results are achieved when this ratio ranges from about 0.01 to
about 0.3 mole per gram atom of titanium.
[0055] Preferably, the aforesaid electron donor compounds and
titanium compound is contacted with the precipitated solid
particles in the presence of an inert hydrocarbon or halogenated
diluent, although other suitable techniques can be employed.
Suitable diluents are substantially inert to the components
employed and are liquid at the temperature and pressure
employed.
[0056] Preferably, although optional, the precipitated particles
are reprecipitated from a solution containing, typically, a cyclic
ether, and then the reprecipitated particles are treated with a
transition metal compound and an electron donor as described
above
[0057] In a typical reprecipitation procedure, the precipitated
particles are entirely solubilized in a cyclic ether solvent and
then particles are allowed to reprecipitate to form particles of
uniform size. The preferable ether is tetrahydrofuran, although
other suitable cyclic ethers, such as tetrahydropyran and
2-methyltetrahydrofuran, may be used, which can solubilize the
particles. Also, thioethers such as tetrahydrothiophene can be
used. In some instances, such as the use of 2,2,5,5-tetrahydrofuran
and tetrahydropyran-2-methanol, reprecipitation occurs upon heating
to about 55.degree.-85.degree. C. Other compounds may be used which
act in an equivalent manner, i.e., materials which can solubilize
the particles formed in Step B and from which solid uniform
particles can be reprecipitated, such as cyclohexene oxide,
cyclohexanone, ethyl acetate and phenyl acetate. Mixtures of such
suitable materials may also be used.
[0058] A suitable diluent that can be used in any of the aforesaid
steps should be substantially inert to the reactants employed and
preferably is liquid at the temperatures and pressures used. A
particular step may be conducted at an elevated pressure so that
lower boiling diluents can be used at higher temperatures. Typical
suitable diluents are aromatic or substituted aromatic liquids,
although other hydrocarbon-based liquids may be used. Aromatic
hydrocarbons, such as toluene, and substituted aromatics are
useful. An especially suitable diluent is a halogenated aromatic
such as chlorobenzene or a mixture of a halogenated aromatic such
as chlorobenzene and a halogenated aliphatic such as
dichloroethane. Also useful are higher boiling aliphatic liquids
such as kerosene. Mixtures of diluents may be used. One useful
diluent component is Isopar G.RTM. which is a C.sub.10-average
isoparaffinic hydrocarbon boiling at 156-176.degree. C. Other
examples of useful diluents include alkanes such as hexane,
cyclohexane, methylcyclohexane, heptane, octane, nonane, decane,
undecane, and the like; haloalkanes such as 1,2-dichloroethane,
1,1,2-trichloroethane, carbon tetrachloride and the like; aromatics
such as benzene, toluene, xylenes and ethylbenzene; and halogenated
and hydrogenated aromatics such as chlorobenzene and
o-di-chlorobenzene.
[0059] Each of the aforesaid preparative steps is conducted in the
substantial absence of water, oxygen, carbon monoxide, and other
extraneous materials capable of adversely affecting the performance
of the catalyst or catalyst component of this invention. Such
materials are conveniently excluded by carrying out the procedures
in the presence of an inert gas such as nitrogen or argon, or by
other suitable means. Optionally, all or part of the process can be
conducted in the presence of one or more alpha-olefins which, when
introduced into the preparative system in gaseous form, can serve
to exclude catalyst poisons. The presence of one or more
alpha-olefins also can result in improved stereospecificity. Useful
alpha-olefins include ethylene, propylene, butene-1, pentene-1,
4-methylpentene-1, hexene-1, and mixtures thereof. Of course, any
alpha-olefin employed should be of relatively high purity, for
example, polymerization grade or higher. Other precautions which
aid in excluding extraneous poisons include purification of any
diluent to be employed, such as by percolation through molecular
sieves and/or silica gel prior to use, and drying and/or purifying
other reagents.
[0060] As a result of the above-described preparation steps, there
is obtained a solid reaction product suitable for use as a catalyst
or catalyst component. Prior to such use, it is desirable to remove
incompletely-reacted starting materials from the solid reaction
product. This is conveniently accomplished by washing the solid,
after separation from any preparative diluent, with a suitable
solvent, such as a liquid hydrocarbon or chlorocarbon, preferably
within a short time after completion of the preparative reaction
because prolonged contact between the catalyst component and
unreacted starting materials may adversely affect catalyst
component performance.
[0061] Although not required, the final solid reaction product
prepared may be contacted with at least one Lewis acid prior to
polymerization. Such Lewis acids useful according to this invention
are materials which are liquid or soluble in a liquid diluent at
treatment temperatures and have a Lewis acidity high enough to
remove impurities such as unreacted starting materials and poorly
affixed compounds from the surface of the solid reaction product.
Preferred Lewis acids include halides of Group III-V metals which
are in the liquid state at temperatures up to about 170.degree. C.
Specific examples of such materials include BCl.sub.3, AlBr.sub.3,
TiCl.sub.4, TiBr.sub.4, SiCl.sub.4, GeCl.sub.4, SnCl.sub.4,
PCl.sub.3 and SbCl.sub.5. Preferable Lewis acids are TiCl.sub.4 and
SiCl.sub.4. Mixtures of Lewis acids can be employed if desired.
Such Lewis acid may be used in a compatible diluent.
[0062] Although not required, the final solid reaction product may
be washed with an inert liquid hydrocarbon or halogenated
hydrocarbon before contact with a Lewis acid. If such a wash is
conducted, it is preferred to substantially remove the inert liquid
prior to contacting the washed solid with Lewis acid.
[0063] In an advantageous procedure, the precipitated particles are
treated with titanium tetrachloride and then with titanium
tetrachloride in the presence of the mixture of electron donors.
More preferably, the product is treated one or more times with a
liquid aromatic hydrocarbon such as toluene and finally with
titanium tetrachloride again.
[0064] In an embodiment of this invention, a mixture of electron
donors is incorporated into the supported catalyst component
comprising a first electron donor and an additional electron donor.
The first electron donor is selected from the group of electron
donors described above as representing the class of electron donors
of this invention. The second electron donor is a dialkylphthalate
wherein each alkyl group may be the same or different and contains
from 3 to 5 carbon atoms. The additional electron donor is
preferably a dibutylphthalate and more preferably is
di-n-butylphthalate or di-i-butylphthalate. The mole ratio of the
additional electron donor to the first electron donor may range
from about 0.1:1 to about 20:1, preferably from about 0.3:1 to
about 1:1.
[0065] Also, the internal electron donor material useful in this
invention may be combined with additional electron donors such as a
polyhydrocarbyl phosphonate, phosphinate, phosphate or phosphine
oxide or an alkyl aralkylphthalate, wherein the alkyl moiety
contains from 2 to 10, preferably 3 to 6, carbon atoms and the
aralkyl moiety contains from 7 to 10, preferably to 8, carbon
atoms, or an alkyl ester of an aromatic monocarboxylic acid wherein
the monocarboxylic acid moiety contains from 6 to 8 carbon atoms
and the alkyl moiety contains from 1 to 3 carbon atoms.
[0066] Useful polyhydrocarbyl phosphonates, phosphinates,
phosphates, or phosphine oxides include:
##STR00016##
wherein each hydrocarbyl group (R.sub.1, R.sub.2, and R.sub.3) may
be the same or different and may be alkyl or aryl, and each
contains from 1 to 12 carbon atoms
[0067] Preferably each hydrocarbyl group (R.sub.1, R.sub.2 and
R.sub.3) is an alkyl group. Preferably a phosphonate is employed.
Particular phosphonates that are suitable for use as an aforesaid
preferable component include dimethyl methylphosphonate, diethyl
ethylphosphonate, diisopropyl methylphosphonate,
dibutylbutylphosphonate, and di(2-ethylhexyl) 2-ethylhexyl
phosphonate.
[0068] The additional component also may be a dialkylphthalate
wherein each alkyl moiety may be the same or different and each
contains at least 6 carbon atoms, preferably up to 10 atoms.
Particular dialkylphthalates which are suitable for use as an
additional electron donor include dihexylphthalate and
dioctylphthalate.
[0069] Also, the additional component may be an alkyl ester of an
aliphatic monocarboxylic acid wherein carboxylic acid moiety
contains 2 to 20, preferably 3 to 6, carbon atoms and the alkyl
moiety contains from 1 to 3 carbon atoms. Particular alkyl esters
that are suitable for use as the aforesaid first electron donor
include methyl valerate, ethyl pivalate, methyl pivalate, methyl
butyrate, and ethyl propionate.
[0070] In another alternative, the additional component may be a
dicycloaliphatic ester of an aromatic dicarboxylic acid wherein
each cycloaliphatic moiety may be the same or different and each
contains from 5 to 7 carbon atoms, and preferably contains 6 carbon
atoms. Preferably the ester is a dicycloaliphatic diester of an
ortho aromatic dicarboxylic acid. Particular dicycloaliphatic
esters that are suitable for use as the aforesaid first electron
donor include dicyclopentylphthalate, dicyclohexylphthalate, and
di-(methylcyclopentyl)-phthalate.
[0071] The additional component may be an alkyl aralkyl phthalate
wherein the alkyl moiety contains 2 to 10, preferably 3 to 6,
carbon atoms, and the aralkyl moiety contains from 7 carbon atoms
up to 10, preferably up to 8, carbon atoms. Particularly, alkyl
aralkyl phthalates suitable for use as an additional component
include benzyl n-butyl phthalate and benzyl i-butyl phthalate. In
another alternative, such additional component also may be an alkyl
ester of an aromatic monocarboxylic acid wherein the monocarboxylic
acid moiety contains from 6 to 8 carbon atoms and the alkyl moiety
contains from 1 to 3 carbon atoms. Particular alkyl esters that are
suitable for use as an additional component include methyl toluate,
ethyl toluate, methyl benzoate, ethyl benzoate and propyl
benzoate.
[0072] The mole ratio of first electron donor component described
in this invention to the additional component is in the range of
from about 0.5:1, preferably from about 1:1, to about 3:1,
preferably to about 2.5:1. The mole ratio of the aforesaid second
electron donor to the combination of the first electron donor and
the additional electron donor ranges from about 4:1, preferably
from about 7:1, to about 15:1, preferably to about 9:1.
[0073] Although the chemical structure of the catalyst or catalyst
components of this invention is not known precisely, the components
generally comprise from about 1 to about 6 weight percent titanium,
from about 10 to about 25 weight percent magnesium, and from about
45 to about 65 weight percent halogen. Preferably, the catalyst
component of this invention comprise from about 2.0 to about 4
weight percent titanium, from about 15 to about 21 weight percent
magnesium and from about 55 to about 65 weight percent
chlorine.
[0074] In the solid catalyst component of this invention produced
by the method of this invention, the atomic ratio of magnesium to
titanium is at least about 0.3:1 and preferably, is from about
0.4:1 to about 20:1 and more preferably, from about 3:1 to about
9:1.
[0075] Prepolymerization or encapsulation of the catalyst or
catalyst component of this invention also may be carried out prior
to being used in the polymerization or copolymerization of alpha
olefins. A particularly useful prepolymerization procedure is
described in U.S. Pat. No. 4,579,836, which is incorporated herein
by reference.
[0076] Typically, the catalyst or catalyst component of this
invention is used in conjunction with a cocatalyst component
including a Group II or III metal alkyl and, typically, one or more
modifier compounds. Useful Group II and IIIA metal alkyls are
compounds of the formula MR.sub.m wherein M is a Group II or IIIA
metal, each R is independently an alkyl radical of 1 to about 20
carbon atoms, and m corresponds to the valence of M. Examples of
useful metals, M, include magnesium, calcium, zinc, cadmium,
aluminum, and gallium. Examples of suitable alkyl radicals, R,
include methyl, ethyl, butyl, hexyl, decyl, tetradecyl, and
eicosyl. From the standpoint of catalyst component performance,
preferred Group II and IIIA metal alkyls are those of magnesium,
zinc, and aluminum wherein the alkyl radicals contain 1 to about 12
carbon atoms. Specific examples of such compounds include
Mg(CH.sub.3).sub.2, Mg(C.sub.2H.sub.5).sub.2,
Mg(C.sub.2H.sub.5)(C.sub.4H.sub.9), Mg(C.sub.4H.sub.9).sub.2,
Mg(C.sub.6H.sub.13).sub.2, Mg(C.sub.12H.sub.25).sub.2,
Zn(CH.sub.3).sub.2, Zn(C.sub.2H.sub.5).sub.2,
Zn(C.sub.4H.sub.9).sub.2, Zn(C.sub.4H.sub.9) (C.sub.8H.sub.17),
Zn(C.sub.6H.sub.13).sub.2, Zn(C.sub.6H.sub.13).sub.3, and
Al(C.sub.12H.sub.25).sub.3. A magnesium, zinc, or aluminum alkyl
containing 1 to about 6 carbon atoms per alkyl radical may be used.
Aluminum alkyls are preferred and most preferably trialkylaluminums
containing 1 to about 6 carbon atoms per alkyl radical, and
particularly triethylaluminum and triisobutylaluminum or a
combination thereof are used.
[0077] If desired, metal alkyls having one or more halogen or
hydride groups can be employed, such as ethylaluminum dichloride,
diethylaluminum chloride, diethylaluminum hydride,
diisobutylaluminum hydride, and the like.
[0078] A typical catalyst system for the polymerization or
copolymerization of alpha olefins is formed by combining the
supported titanium-containing catalyst or catalyst component of
this invention and an alkyl aluminum compound as a co-catalyst,
together with at least one external modifier which typically is an
electron donor and, preferably, is a silane. Typically, useful
aluminum-to-titanium atomic ratios in such catalyst systems are
about 10 to about 500 and preferably about 30 to about 300. Typical
aluminum-to-electron donor molar ratios in such catalyst systems
are about 2 to about 60. Typical aluminum-to-silane compound molar
ratios in such catalyst systems are about 3 to about 50.
[0079] To optimize the activity and stereospecificity of this
cocatalyst system, it is preferred to employ one or more external
modifiers, typically electron donors, and including compounds such
as silanes, mineral acids, organometallic chalcogenide derivatives
of hydrogen sulfide, organic acids, organic acid esters and
mixtures thereof.
[0080] Organic electron donors useful as external modifiers for the
aforesaid cocatalyst system are organic compounds containing
oxygen, silicon, nitrogen, sulfur, and/or phosphorus. Such
compounds include organic acids, organic acid anhydrides, organic
acid esters, alcohols, ethers, aldehydes, ketones, silanes, amines,
amine oxides, amides, thiols, various phosphorus acid esters and
amides, and the like. Mixtures of organic electron donors also may
be used.
[0081] Particular organic acids and esters are benzoic acid,
halobenzoic acids, phthalic acid, isophthalic acid, terephthalic
acid, and the alkyl esters thereof wherein the alkyl group contains
1 to 6 carbon atoms such as methyl chlorobenzoates, butyl benzoate,
isobutyl benzoate, methyl anisate, ethyl anisate, methyl p-toluate,
hexylbenzoate, and cyclohexyl benzoate, and diisobutyl phthalate as
these give good results in terms of activity and stereospecificity
and are convenient to use.
[0082] The aforesaid cocatalyst system advantageously and
preferably contains an aliphatic or aromatic silane external
modifier. Preferable silanes useful in the aforesaid cocatalyst
system include alkyl-, aryl-, and/or alkoxy-substituted silanes
containing hydrocarbon moieties with 1 to about 20 carbon atoms.
Especially preferred are silanes having a formula: SiY.sub.4,
wherein each Y group is the same or different and is an alkyl or
alkoxy group containing 1 to about 20 carbon atoms. Preferred
silanes include isobutyltrimethoxysilane,
diisobutyldimethoxysilane, diisopropyldimethoxysilane,
n-propyltriethoxysilane, isobutylmethyldimethoxysilane,
isobutylisopropyledimethoxysilane, dicyclopentyldimethoxysilane,
tetraethylorthosilicate, dicyclohexyldimethoxysilane,
diphenyldimethoxysilane, di-t-butyldimethoxysilane, and
t-butyltrimethoxysilane.
[0083] In one aspect of this invention the substituted cycloalkane
dicarboxylates identified above as catalyst component internal
donors may be used as external donors alone or in combination with
other suitable external donors including the above-identified
silane compounds.
[0084] The catalyst or catalyst component of this invention is
useful in the stereospecific polymerization or copolymerization of
alpha-olefins containing 3 or more carbon atoms such as propylene,
butene-1, pentene-1, 4-methylpentene-1, and hexene-1, as well as
mixtures thereof and mixtures thereof with ethylene. The catalyst
or catalyst component of this invention is particularly effective
in the stereospecific polymerization or copolymerization of
propylene or mixtures thereof with up to about 30 mole percent
ethylene or a higher alpha-olefin. According to the invention,
highly crystalline polyalpha-olefin homopolymers or copolymers are
prepared by contacting at least one alpha-olefin with the
above-described catalyst or catalyst component of this invention
under polymerization or copolymerization conditions. Such
conditions include polymerization or copolymerization temperature
and time, pressure(s) of the monomer(s), avoidance of contamination
of catalyst, choice of polymerization or copolymerization medium in
slurry processes, the use of additives to control homopolymer or
copolymer molecular weights, and other conditions well known to
persons skilled in the art. Slurry-, bulk-, and vapor-phase
polymerization or copolymerization processes are contemplated
herein.
[0085] The amount of the catalyst or catalyst component of this
invention to be used varies depending on choice of polymerization
or copolymerization technique, reactor size, monomer to be
polymerized or copolymerized, and other factors known to persons of
skill in the art, and can be determined on the basis of the
examples appearing hereinafter. Typically, a catalyst or catalyst
component of this invention is used in amounts ranging from about
0.2 to 0.02 milligrams of catalyst to gram of polymer or copolymer
produced.
[0086] Irrespective of the polymerization or copolymerization
process employed, polymerization or copolymerization should be
carried out at temperatures sufficiently high to ensure reasonable
polymerization or copolymerization rates and avoid unduly long
reactor residence times, but not so high as to result in the
production of unreasonably high levels of stereorandom products due
to excessively rapid polymerization or copolymerization rates.
Generally, temperatures range from about 0.degree. to about
120.degree. C. with a range of from about 20.degree. C. to about
95.degree. C. being preferred from the standpoint of attaining good
catalyst performance and high production rates. More preferably,
polymerization according to this invention is carried out at
temperatures ranging from about 50.degree. C. to about 80.degree.
C.
[0087] Olefin polymerization or copolymerization according to this
invention is carried out at monomer pressures of about atmospheric
or above. Generally, monomer pressures range from about 20 to about
600 psi (140 to 4100 kPa), although in vapor phase polymerizations
or copolymerizations, monomer pressures should not be below the
vapor pressure at the polymerization or copolymerization
temperature of the alpha-olefin to be polymerized or
copolymerized.
[0088] The polymerization or copolymerization time will generally
range from about 1/2 to several hours in batch processes with
corresponding average residence times in continuous processes.
Polymerization or copolymerization times ranging from about 1 to
about 4 hours are typical in autoclave-type reactions. In slurry
processes, the polymerization or copolymerization time can be
regulated as desired. Polymerization or copolymerization times
ranging from about 1/2 to several hours are generally sufficient in
continuous slurry processes.
[0089] Diluents suitable for use in slurry polymerization or
copolymerization processes include alkanes and cycloalkanes such as
pentane, hexane, heptane, n-octane, isooctane, cyclohexane, and
methylcyclohexane; alkylaromatics such as toluene, xylene,
ethylbenzene, isopropylbenzene, ethyl toluene, n-propyl-benzene,
diethylbenzenes, and mono- and dialkylnaphthalenes; halogenated and
hydrogenated aromatics such as chlorobenzene. Chloronaphthalene,
ortho-dichlorobenzene, tetrahydro-naphthalene,
decahydronaphthalene; high molecular weight liquid paraffins or
mixtures thereof, and other well-known diluents. It often is
desirable to purify the polymerization or copolymerization medium
prior to use, such as by distillation, percolation through
molecular sieves, contacting with a compound such as an
alkylaluminum compound capable of removing trace impurities, or by
other suitable means.
[0090] Examples of gas-phase polymerization or copolymerization
processes in which the catalyst or catalyst component of this
invention is useful include both stirred bed reactors and fluidized
bed reactor systems and are described in U.S. Pat. Nos. 3,957,448;
3,965,083; 3,971,786; 3,970,611; 4,129,701; 4,101,289; 3,652,527;
and 4,003,712, all incorporated by reference herein. Typical gas
phase olefin polymerization or copolymerization reactor systems
comprise at least one reactor vessel to which olefin monomer and
catalyst components can be added and which contain an agitated bed
of forming polymer particles. Typically, catalyst components are
added together or separately through one or more valve-controlled
ports in the single or first reactor vessel. Olefin monomer,
typically, is provided to the reactor through a recycle gas system
in which unreacted monomer removed as off-gas and fresh feed
monomer are mixed and injected into the reactor vessel. For
production of impact copolymers, homopolymer formed from the first
monomer in the first reactor is reacted with the second monomer in
the second reactor. A quench liquid, which can be liquid monomer,
can be added to polymerizing or copolymerizing olefin through the
recycle gas system in order to control temperature.
[0091] Irrespective of polymerization or copolymerization
technique, polymerization or copolymerization is carried out under
conditions that exclude oxygen, water, and other materials that act
as catalyst poisons. Also, according to this invention,
polymerization or copolymerization can be carried out in the
presence of additives to control polymer or copolymer molecular
weights. Hydrogen is typically employed for this purpose in a
manner well known to persons of skill in the art. Although not
usually required, upon completion of polymerization or
copolymerization, or when it is desired to terminate polymerization
or copolymerization or at least temporarily deactivate the catalyst
or catalyst component of this invention, the catalyst can be
contacted with water, alcohols, acetone, or other suitable catalyst
deactivators in a manner known to persons of skill in the art.
[0092] The products produced in accordance with the process of this
invention are normally solid, predominantly isotactic
polyalpha-olefins. Homopolymer or copolymer yields are sufficiently
high relative to the amount of catalyst employed so that useful
products can be obtained without separation of catalyst residues.
Further, levels of stereorandom by-products are sufficiently low so
that useful products can be obtained without separation thereof.
The polymeric or copolymeric products produced in the presence of
the invented catalyst can be fabricated into useful articles by
extrusion, injection molding, and other common techniques.
[0093] The polymer component of the composition of this invention
primarily contains a high crystalline polymer of propylene.
Polymers of propylene having substantial polypropylene
crystallinity content now are well-known in the art. It has long
been recognized that crystalline propylene polymers, described as
"isotactic" polypropylene, contain crystalline domains interspersed
with some non-crystalline domains. Noncrystallinity can be due to
defects in the regular isotactic polymer chain which prevent
perfect polymer crystal formation. The extent of polypropylene
stereoregularity in a polymer can be measured by well-known
techniques such as isotactic index, crystalline melting
temperature, flexural modulus, and, recently by determining the
relative percent of meso pentads (% m4) by carbon-13 nuclear
magnetic resonance (.sup.13C NMR).
[0094] The propylene polymer especially useful in this invention
has both a high nmr tacticity and a broadened molecular weight
distribution ("MWD") as measured by the ration of the weight
average to number average molecular weights (M.sub.w/M.sub.n). Such
molecular weights typically are measured by gel permeation
chromatography (GPC) techniques known in the art. In addition,
preferable polymers of this invention have flexural moduli above
about 1800 MPa and typically above about 2100 MPa. In addition the
nmr pentad tacticity typically is above 90% and preferably is above
about 95% and may be above about 97%. Typical polymer melt flow
rates are 1 to 20 g/10 min.
[0095] A method to determine stereoregularity of a propylene
polymer uses .sup.13C NMR and is based on the ability to identify
relative positions of adjacent methyl groups on a polypropylene
polymer backbone. If the methyl groups of two adjacent propylene
monomer units (--CH(CH.sub.3)--CH.sub.2--) are on the same side of
the polymer chain, such two methyl groups form a meso ("m") dyad.
The relative percentage of these meso dyads is expressed as %m. If
the two methyl groups of adjacent monomer units are on opposite
sides of the polymer chain, such two methyl groups form a racemic
("r") dyad, and the relative percentage of these racemic dyads is
expressed as % r. Advances in .sup.13C NMR techniques permit
measurement of the relative positioning of three, four, and five
successive methyl groups, which are referred to as triads, tetrads
and pentads, respectively.
[0096] Current NMR instruments can quantify the specific
distribution of pentads in a polymer sample. There are ten unique
pentads which are possible in a propylene polymer:
TABLE-US-00001 m m m m r r r r m m m r m m r m m m r r m r r m r m
m r r m r m r m r r m r r r
[0097] A ball and stick representation of the mmmm pentad is:
[0098] m m m m [0099] -i-i-i-i-i-
[0100] Two of the possible pentads cannot be separated by NMR (mmrm
and rmmr) and are reported together. Two of the ten pentads (mmrr
and mrrm) result from the displacement of a single methyl group on
the opposite side of the polymer chain in an isotactic sequence.
Since the mmmm (m4) pentad represents a perfect isotactic
stereoregular structure, measurement of this pentad (as % m4)
reflects isotacticity and potential crystallinity. As used herein,
the term NMR tacticity index is the percent of m4 (% m4) pentads as
measured by .sup.13C NMR. Thus, if 96% of pentads measured by
.sup.13C NMR in a propylene polymer are m4, the NMR tacticity index
is 96.
[0101] The invention described herein is illustrated, but not
limited, by the following examples.
EXAMPLES
[0102] A series of supported catalyst components are prepared using
various mixtures of internal electron donors. Examples using
electron donors of this invention are described below, together
with Comparative Runs not using such internal electron donors.
[0103] Step A--Formation of Magnesium Alkyl Carbonate Solution
[0104] Into a two-liter reactor, equipped with a mechanical stirrer
and flushed with dry nitrogen, is transferred a mixture of 153
grams of magnesium ethoxide, 276 milliliters of 2-ethyl-1-hexanol
and 1100 milliliters of toluene. This mixture is agitated at 450
rpm under 30 psig of carbon dioxide and heated at 93.degree. C. for
three hours. The resulting solution (1530 milliliters) is
transferred to a two-liter bottle. The solution contains 0.10
gram-equivalents of magnesium ethoxide per milliliter.
[0105] Step B--Formation of Solid Particles
[0106] Into a 1.0-liter reactor is charged 150 milliliters of
toluene, 20.5 milliliters of tetraethoxysilane, and 14 milliliters
of titanium tetrachloride under a blanket of dry nitrogen. After
the mixture is stirred at 300 rpm at 22-27.degree. C. for 15
minutes, 114 milliliters of the Step A magnesium hydrocarbyl
carbonate solution is added to the reactor through a bomb and
thereafter solid particles precipitate.
[0107] Step C--Reprecipitation
[0108] After the mixture containing the precipitate is stirred for
five additional minutes, 27 milliliters of tetrahydrofuran (THF)
were added rapidly through a syringe. The temperature in the
reactor rises from 26.degree. C. to 38.degree. C. Whereupon, the
stirring is maintained at 300 rpm and the temperature is increased
to 60.degree. C. within 15 minutes. The first formed solid
dissolves in the THF solution. Within about 5 minutes after the THF
addition, a solid begns to reprecipitate from solution. Stirring is
continued for 1 hour at 60.degree. C. after which agitation is
stopped and the resulting solid is allowed to settle. Supernatant
is decanted and the solid washed two times with 50-milliliter
portions of toluene.
[0109] Step D--Titanium (IV) Compound Treatment
[0110] To the solid from Step C in the one-liter reactor are added
125 milliliters of toluene and 50 milliliters of titanium
tetrachloride. The resulting mixture is heated to 116.degree. C.
within 30 minutes and stirred at 300 rpm for one hour. After
stirring is stopped, the resulting solid is allowed to settle and
the supernatant is decanted. After 150 milliliters of toluene, 50
milliliters of titanium tetrachloride, the electron donor compounds
of this invention are added to the resulting solid, the mixture is
stirred at 300 rpm at 117.degree. C. for 90 minutes, the solid is
allowed to settle and supernatant liquid is decanted. After 95
milliliters of toluene are added, the mixture is heated to
91.degree. C. for 30 minutes. After the agitation is stopped, the
solid is allowed to settle and the supernatant decanted. An
additional 125 milliliters of titanium tetrachloride are added, the
mixture is heated at 91.degree. C. under agitation for 30 minutes,
after which the agitation is stopped, and the supernatant liquid is
decanted. The residue is washed four times with 50-milliliter
portions of hexane and the solids are recovered. The mole ratio of
magnesium/titanium/electron donor components in the reactants for
the examples is 1/5/0.45.
[0111] Batch slurry phase propylene polymerization evaluation is
performed in a two liter reactor at 71.degree. C. at a total
reactor pressure of 150 pounds per square inch gauge with 7
millimoles of hydrogen, while stirring at 500 revolutions per
minute with a reaction time of 2 hours. Triethylaluminum (TEA) is
used as a co-catalyst together with diisobutyldimethoxysilane as an
external modifier. The reactor is charged with TEA/modifier,
titanium component, hydrogen, and propylene in that order.
[0112] In a typical procedure, a dry, nitrogen-purged, two-liter
stainless steel autoclave reactor was charged with catalyst
(.about.20 mg), triethylaluminum (3.6 mL of a 0.75 M solution in
heptane), and diisobutyldimethoxysilane (1.0 mL of a 0.15 M
solution in heptane), and 850 mL of heptane at 40 C. Hydrogen was
introduced at 12.5 psig. Agitation and heating was started and a 15
psig pressure drop from a 75 mL vessel containing hydrogen was
introduced to the reactor followed by an approximately 30 gram
portion of propylene. When the temperature reaches 70 C, the
propylene reservoir to the reactor was opened and a constant
propylene pressure of 150 psig is maintained for one hour. The
reactor was then vented and the resulting polymer slurry dumped
from the reactor, filtered and dried. Analysis was performed after
oven drying and weighing of the polymer powder.
[0113] Catalyst components were prepared in a manner consistent
with the above-described procedure using various internal donors.
Test runs using various internal modifiers are shown in Table
1.
TABLE-US-00002 TABLE 1 Yield MFR Bulk (g/g (g/10 Density XS Mn Mw
Mz Mz + 1 Run Modifier Structure PP) min) (g/cc) (wt. %) (X
10.sup.-3) (X 10.sup.-3) (X 10.sup.-3) (x10.sup.-3) M.sub.w/M.sub.n
M.sub.z/M.sub.w 1 ##STR00017## 8160 8.40 0.425 2.7 50.2 272 894
2053 5.42 3.29 2 ##STR00018## 6080 11.68 0.397 4.78 44.6 259 917
2128 5.81 3.54 3* ##STR00019## 5390 10.60 0.405 5.35 46.2 264 943
2173 5.71 3.57 4 ##STR00020## 3370 11.76 0.337 5.9 49.6 258 984
2505 5.20 3.81 5 ##STR00021## 5330 11.55 0.39 6.47 44.4 261 1009
2465 5.88 3.87 6 ##STR00022##
[0114] "Yield" (grams of polymer produced per gram of solid
catalyst component) is based on the weight of solid catalyst used
to produce polymer. "Solubles" are determined by evaporating the
solvent from an aliquot of filtrate to recover the amount of
soluble polymer produced and are reported as the weight percent (%
Sol.) of such soluble polymer based on the sum of the weights of
the solid polymer isolated by filtration and of the soluble
polymer. "Xylene Solubles" ("XS") are Solubles using boiling
xylenes as the solvent. "Extractables" are determined by measuring
the loss in weight of a dry sample of ground polymer after being
extracted in boiling n-hexane for three to six hours and are
reported as the weight percent (% Ext.) of the solid polymer
removed by the extraction. The bulk density (BD) is reported in
units of pounds per cubic foot (1 lbs/ft.sup.3=0.0149 g/ml). The
viscosity of the solid polymer was measured according to ASTM D1238
Condition L (2.16 kg.COPYRGT.230.degree. C.) and reported as the
melt flow rate (MFR) in grams of polymer per 10 minutes.
[0115] Decalin Solubles ("DS") is a measure of hydrocarbon soluble
and extractable materials, such as atactic, non-crystalline, and
oligomeric components, contained in a propylene polymer and is
useful in correlating a particular resin to desirable resin
properties such as processing window. DS is determined by
completely dissolving a 2.0-gram sample of polymer in 100
milliliters of Irganox 1076-stabilized (0.020 grams/liter) decalin
(decahydronaphthalene) by warming the slurry to 165.degree. C. and
stirring the slurry for two hours. Once the polymer is dissolved,
the solution is allowed to cool overnight (at least 16 hours).
After the cooling period, the solution is filtered from the
precipitated polymer. A measured portion of the solution is
withdrawn and, after removing the decalin solvent, the resulting
samples are completely dried in a 120.degree. C. vacuum oven. The
final dried samples are weighed to determine the amount of
decalin-soluble polymer. Results are reported as a weight percent
polymer remaining soluble in decalin.
[0116] In order to demonstrate this invention further, propylene
polymerizations are conducted in a laboratory gas-phase reactor
using a magnesium halide supported HAC catalyst component produced
in accordance with U.S. Pat. No. 4,886,022. The catalyst component
contains 17.32 wt. % magnesium and 2.29 wt % titanium.
Triethylaluminum is used as the co-catalyst. The amount of silane
modifier is controlled in the polymerizations such that the Al/Si
ratio was in the range 6 to 24 and the target melt flow rate (MFR)
of the polymer is 1 to 50. These propylene polymerizations are
performed in a one-gallon (3.8-liter) continuous, horizontal,
cylindrical gas-phase reactor measuring 10 cm in diameter and 30 cm
in length based on that described in U.S. Pat. No. 3,965,083. The
reactor is equipped with an off-gas port for recycling reactor gas
through a condenser and back through a recycle line to the recycle
nozzles in the reactor. Propylene liquid is used as the quench
liquid to help remove the heat generated in the reactor during the
polymerization. During operation, polypropylene powder produced in
the reactor bed, passes over a weir, and was discharged through a
powder discharge system into a secondary closed vessel blanketed
with nitrogen. The polymer bed is agitated by paddles attached to a
longitudinal shaft within the reactor that was rotated at about 75
rpm. The reactor pressure is maintained 300 psig (2100 kPa). The
titanium/magnesium-containing catalyst was introduced into the
reactor as a 1.5 wt % slurry in heptane through a liquid
propylene-flushed catalyst addition nozzle. A mixture of the silane
modifier and triethylaluminum in heptane at Al/Mg and Al/Si molar
ratios indicated in Table I are fed separately to the reactor
through a liquid propylene-flushed co-catalyst addition nozzle.
Hydrogen was fed to the reactor. Production rate is about 200
g/hr.
* * * * *