Compounds of the rare earths and their use as polymerization...

Details Compounds of the rare earths and their use as polymerization... Compounds of the rare earths and their use as polymerization...

1998-05-07

2001-09-04

Kelly, Cynthia H. (Department: 1774)

Catalyst, solid sorbent, or support therefor: product or process

Catalyst or precursor therefor

Plural component system comprising a - group i to iv metal...

C502S152000, C502S154000, C502S153000, C502S155000, C502S156000, C526S164000

Reexamination Certificate

active

06284697

ABSTRACT:

This invention relates to a catalyst, to the preparation thereof, and to the use thereof for the polymerisation of unsaturated compounds, particularly of conjugated dienes, in solution and in the gas phase.
Polybutadiene which comprises a high proportion of cis-1,4-units has long been produced on an industrial scale and is used for the production of automobile tires and other rubber products. It is polymerised in the liquid phase, using very different catalyst systems. One particularly advantageous catalyst system for the production of polybutadiene comprising a high proportion of cis-1,4-units is described in EP 11184. The catalyst system which is described therein and which is used for the polymerisation of butadiene in solution consists of a rare earth carboxylate, an aluminum alkyl and a halogen-containing Lewis acid. On the other hand, the Ziegler-Natta system based on inorganic salts of the rare earths which is known in the art contains, in addition to halogen-free organoaluminium compounds, partially- and/or perfluorinated organoboron Lewis acids for the production of 1,4-polydiolefines in solution. It is also known that allyl complexes of the rare earths, in combination with co-catalysts, preferably in combination with alumoxanes in this respect, and in non-polar solvents such as toluene and n-heptane, are suitable catalysts for the polymerisation of butadiene to give a high content of 1,4-cis double bonds [R. Tauhe, H. Windisch, S. Maiwald,
Makromol. Symp
. 89 (1995) 393-409].
The polymerisation of conjugated dienes in solution has the disadvantage that during the separation of unreacted monomers and of the solvent from the polymer which is formed, low molecular weight compounds can enter the environment via the drawn-off air and via the waste water and therefore have to be disposed of. In addition, large amounts of solvents have to be used, and have to be separated at a high energy cost. The solvents are generally combustible and readily flammable, and therefore constitute a potential hazard.
In recent years, the gas phase process has been proved to be particularly advantageous, especially for the production of polyethylene and polypropylene, and has become widespread industrially. The advantages of the gas phase process are due in particular to the fact that no solvents are used, and emissions and waste water contamination can be reduced.
Compared with the multiplicity of Ziegler-Natta systems which are based on titanium, cobalt, nickel or neodymium and which are suitable for solution polymerisation, only a few catalyst systems have hitherto been known for the polymerisation of conjugated dienes, particularly to form polybutadiene, from the gas phase. In DE 4334045, EP 727447 and WO 96/31543, catalyst systems were described for the first time which made it possible to polymerise conjugated dienes, particularly butadiene, in the gas phase. The catalysts described there consist of Ziegler-Natta catalysts based on compounds of the rare earths, organoaluminium Lewis aids, and an inorganic support. Another catalyst of system, which is described in WO 96/31544, consists of allyl compounds of the rare earths in combination with aluminum-containing organometallic Lewis acids on inert inorganic support materials. In particular, polymers with a high content of 1,4-cis double bonds are obtained from the gas phase by using these catalysts. However, very large amounts of organoaluminium compounds are necessary as co-catalysts in all these catalyst systems in order to produce catalysts which have a sufficiently high activity.
For the allyl complexes of the rare earths, particularly the tris(allyl) complexes of neodymium and lanthanum, it is known that these complexes catalyse the polymerisation of butadiene, as definite catalysts without the addition of co-catalysts in aromatic solvents, with the formation of polymers comprising what are mainly 1,4-trans double bonds, wherein the activities of these catalysts are low. With these complexes, polymerisation to form 1,4-cis-butadiene only occurs in the presence of co-catalysts, preferably methylalumoxane [R Taube, H. Windisch, S. Maiwald, H. Hemling, H. Schumann;
J. Organomet. Chem
., 513 (1996) 49-61]. As is generally known alumoxanes are dynamic mixtures of different compounds which are structurally undefined, and which only have a limited shelf life in their commercially available form as solutions in hydrocarbons [“Alumoxanes”,
Macromolecular Symposia
97(1995)].
The object of the present invention was therefore to provide catalysts for the polymerisation of unsaturated compounds, particularly of conjugated dienes such as butadiene, which are suitable, as defined compounds without co-catalysts, for polymerisation in solution and in the gas phase.
Surprisingly, it has now been found that structurally defined allyl complexes of the rare earths, comprising a structurally defined cation based on the rare earths and a corresponding anion, are suitable, without the addition of co-catalysts, for the polymerisation of unsaturated compounds, particularly conjugated dienes such as butadiene, wherein, at a constant level of 1,4-cis selectivity, higher catalytic activities are achieved compared with previously known catalysts.
The present invention therefore relates to a catalyst based on allyl complexes of the rare earths, of formula (I)
[(C
3
R
1
5
)
r
M
1
(X)
2−r
(D)
n
]
+
[M
2
(X)
p
(C
6
H
5−q
R
2
q
)
4−p
]
−
  (I),
wherein
M
1
denotes a trivalent element of the rare earths of atomic
numbers 21, 39, 57 to 71,
X
is the same or different and denotes an anion,
D
is the same or different and denotes a neutral donor ligand,
M
2
represents an element of group IIIb of the periodic table of
the elements (PTE) [F.A. Cotton, G. Wilkinson, Anorganische
Chemie, 4th Edition, VCH Verlagsgesellchaft mbH,
Weinheim, 1985],
R
1
is the same or different and represents hydrogen, a linear or branched,
saturated or singly- or multiply-unsaturated C
1
-C
30
alkyl radical or
C
5
-C
30
cycloakyl radical which may optionally contain one or more
hetero atoms such as N, P, O or S, a C
6
C
30
aryl radical which may
optionally contain one or more hetero atoms, which is optionally
singly- or multiply-substituted by alkyl, alkynyl or alkenyl radicals
comprising 1 to 30 C. atoms or by phenyl groups comprising 6 to
30 carbon atoms and which can be condensed with other aromatic
compounds containing 6 to 30 carbon atoms, or represents a
silyl group which is substituted by alkyl, alkenyl or alkynyl
groups comprising 1 to 30 C. atoms or by phenyl groups comprising
6 to 30 C. atoms,
R
2
is the same or different and represents a fluorine atom or a
fluoroalkyl group comprising 1 to 10 carbon atoms,
n
represents an arbitrary number from 0 to 10, preferably 0 to 5,
p
represents an arbitrary number from 0 to 3, preferably 0 to 2,
q
represents an arbitrary number from 1 to 5, preferably 2 to 5, and
r
represents an arbitrary number from 1 to 2.
Compounds of formula (I) are preferably used in which
M
1
denotes lanthanum, cerium, praseodymium and neodymium or a mixture of
elements of the rare earths, which contains at least 10, preferably 30% by
weight, of at least one of the elements lanthanum, cerium, praseodymium or
neodymium, most preferably lanthanum, praseodyniium or neodymium,
X
denotes an allyl group of formula C
3
R
1
5
, e.g. C
3
H
5
, C
3
H
4
(1-Me), C
3
H
4
(2-Me),
C
3
H
3
(1,3-Me)
2
or C
3
H(1, 1
1
,3, 3
1
-Me)
4
, a halide such as F, Cl, Br or I, a sul-
phonate of formula O
3
SR
1
or O
3
SR
2
, e.g. O
3
SCF
3
, an amide of formula NR
1
2
,
e.g. NPh
2
, N(C
2
H
4
NMe
2
)
2
, N(C
2
H
4
OMe)
2
, N(SiMe
3
)
2
or N(SiHMe
2
)
2
, a
pyridyl of formula NC
5
R
1
5
, e.g. NC
5
H
4
(2-C
2
H
5
NMe
2
), a dipyridyl of formula
N
2
C
10
R
1
8
, e.g. (2,2′-NC
5
H
4
)
2
, a pyrazolate of formula N
2
C
3
R
1
3
, e.g.
N
2
C
3
H(3,5-Ph)
2
, N
2
C
3
H(3-Me)(5-Ph), N
2
C
3
H(3,5-tert.-Bu)
2
, a pyrazolyl
borate of formula R
1
B(N
2
C
3
R
1
3
)
3
, e.g. HB(N
2
C
3
H
3
)
3
or HB(N

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