Catalysts based on vanadium, their preparation and use in...

Details Catalysts based on vanadium, their preparation and use in... Catalysts based on vanadium, their preparation and use in...

1999-11-18

2002-12-17

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S172000, C526S189000, C526S348000, C502S170000, C502S171000, C502S104000

Reexamination Certificate

active

06495641

ABSTRACT:

The present invention relates to a catalyst based on Vanadium, its preparation and its use in the (co)polymerization of &agr;-olefins.
More specifically, the present invention relates to a catalyst consisting of a Vanadium complex, a co-catalyst based on Al alkyl and, optionally, a reactivator. In addition, the present invention relates to a process for the (co)polymerization of &agr;-olefins in the presence of said catalyst.
At present catalysts based on Vanadium consist of a Vanadium complex, an Al alkyl and a chlorinated reactivator. The Vanadium complex is the precursor of the active species which is formed by interaction with the Al alkyl. This species initiates the polymerization but is also easily deactivated by the same Al alkyl, producing a reduction in activity. The reactivator has the function of re-establishing the active species guaranteeing a longer life-time of the catalyst and consequently a greater catalytic activity (see G. Natta et al., Makromol. Chem., 81, 161-172 (1965; E. Adisson, J. Pol. Sc., art A: Polymer Chemistry, Vol. 31, pages 831-839, 1993). In order to have catalytic activity, however, at least one of the reagents must be chlorinated (see G. Natta et al., J. Polym. Sc., Vol. 51, 411-427, 1961). In fact systems such as V(acac)
3
/AlEt
2
Cl or VC
1
4
/Al(C
6
H
13
)
3
are active in the copolymerization of ethylene with propylene, whereas other systems without chlorine such as V(acac)
3
/Al (i-Bu)
3
and V(acac)
3
/AlMe
3
do not give a polymer, but become active when a chlorinated reactivator such as Cl
3
CCOOR, CCl
4
is added to the system (see E. Adisson et al. J. Pol. Sc., Part A, Polymer Chemistry, Vol. 32, pages 1033-1041, 1994).
The presence of chlorine in the catalytic system is particularly harmful in the case of the production of ethylene-propylene elastomeric copolymers (EPR and EP(D)M) with a process in suspension which does not comprise a purification phase from the catalytic residues and in particular chlorine. This inevitably causes a lower purity of the products and consequently excludes use in particular applicative fields (for example cables). In addition, the presence of inorganic chlorine in the polymer may develop hydrochloric acid during the processing of the polymer making it necessary to use anti-acid additives, with a consequent increase in the running costs.
The request for catalytically active Vanadium catalysts in the presence of the smallest possible quantity of chlorine, with activities comparable to or higher than those of the known art, therefore remains unsatisfied.
A new group of catalysts capable of giving copolymers containing a small quantity of residual chlorine, has now been found. These catalysts are based on Vanadium complexes having halogenated carboxyl groups as ligands.
A first object of the present invention therefore relates to a Vanadium complex having general formula (I)
(RCOO)
n
VX
p
L
m
  (I)
wherein R is a monofunctional hydrocarbon radical having from 1 to 20 carbon atoms and from 1 to 6 halogen atoms, selected from chlorine and bromine, preferably chlorine; X is chlorine or bromine, preferably chlorine; L is an electron donor; p+n=3, 4 or 5, preferably=3; n is greater than or equal to 1; m is between 0 and 3.
Examples of R—COO carboxyl groups in formula (I) are selected from:
1) R—COO=
 wherein R
1
, R
2
, R
3
, R
4
and R
5
the same or different, are selected from H, Cl or Br, alkyls, cycloalkyls, aryls, arylalkyls, alkylaryls or alkyls, cycloalkyls, aryls, arylalkyls, alkylaryls containing chlorine or bromine, with the proviso that at least one of the R
1
-R
5
residues is selected from chlorine or bromine, or an alkyl, cycloalkyl aryl, arylalkyl, alkylaryl group containing chlorine or bromine; q varies from 0 to 10.
Non-limiting examples of these derivatives are represented by:
Cl
3
COO, CCl
3
CH
2
COO, CCl
3
(CH
2
)
2
COO, CHCl
2
COO, CH
3
CCl
2
COO, C
6
H
5
CCl
2
CH
2
COO, (C
6
H
5
)
2
CClCOO, CH
3
CH
2
CCl
2
COO, C
6
H
5
CH
2
CH
2
CH
2
C—HClCOO, ClC
6
H
4
CHClCOO, ClC
6
H
4
CH
2
COO, 2-cyclopropyl-2,2-dichloro-acetic acid.
2) R—COO=
 wherein:
R
1
, R
2
, R
3
and R
4
, the same or different, are selected from H, Cl or Br, alkyls, cycloalkyls, aryls, arylalkyls, alkylaryls, or alkyls, cycloalkyls, aryls, arylalkyls, alkylaryls containing chlorine or bromine, with the proviso that at least one of the R
1
-R
4
residues is chlorine or bromine or an alkyl, cycloalkyl aryl, arylalkyl, alkylaryl group containing chlorine or bromine;
r and s vary independently from 0 to 5, with the restriction that r+s is from 1 to 5.
Non-limiting examples of these derivatives are represented by:
Cl
3
CC
6
H
4
COO, ClCH
2
C
6
H
4
COO, ClCH
2
C
6
H
2
Cl
2
COO, C
6
Cl
5
COO
3) R—COO=
 wherein:
Z, R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, the same or different, are selected from H, Cl, Br, alkyl, cycloalkyl, aryl, arylalkyl, alkylaryl, alkyls, cycloalkyls, aryls, arylalkyls, alkylaryls containing chlorine or bromine, with the proviso that at least one of the Z and R
1
-R
6
residues is chlorine or bromine or an alkyl, cycloalkyl aryl, arylalkyl, alkylaryl group containing chlorine or bromine;
t and u independently vary from 0 to 10, preferably from 0 to 2.
Non-limiting examples of these derivatives are represented by:
CCl
3
CH═CHCOO, CCl
3
CCl═CClCOO, CCl
2
═CClCCl
2
COO.
4) R—COO wherein R is selected from cycloalkyl, polycycloalkyl, cycloalkenyl, polycycloalkenyl having from 3 to 20 C atoms, substituted with at least one chlorine or bromine or with hydrocarbyl groups containing at least one chlorine or bromine.
Non-limiting examples of these derivatives are represented by:
2-chloro-cyclohexane carboxylic acid, 2,2-dichlorocyclopropane-carboxylic acid, 2,2-3,3-tetrachlorocyclopropane-carboxylic acid, perchlorocyclohexane carboxylic acid, cyclo hex-2-ene-2-trichloromethyl-carboxylic acid.
As far as L is concerned, i.e. the electron donor, typical examples are alkyl and cycloalkyl ethers, alkyl esters of aromatic and aliphatic carboxylic acids, aliphatic ketones, aliphatic amines, aliphatic alcohols. L is preferably selected from tetrahydrofuran (THF), dimethoxymethane, diethoxyethane.
A second object of the present invention relates to the process for the preparation of the complexes having general formula (I) which comprises:
a) treatment of a Tallium (Tl) salt having the general formula RCOOTl, wherein R has the meaning defined above, with a Vanadium halide, preferably VCl
3
, in an aliphatic or aromatic, ether or chlorinated, hydrocarbon solvent, alone or in a mixture, preferably THF and dimethoxyethane, at temperatures ranging from 0 to 50° C., preferably from 15 to 30° C., for a time ranging from 30 minutes to 6 hours, preferably from 1 to 4 hours;
b) separation, preferably filtration, of the Tl halide formed by the reaction;
c) isolation of the Vanadium complex.
In the preferred embodiment, step (c) is carried out by evaporation of the solvent or precipitation of the complex by the addition of a suitable precipitating agent, usually a hydrocarbon solvent, preferably pentane.
Typical but non-limiting examples of these syntheses are provided in the experimental section, which describes, among others, the preparation of V(CCl
3
COO)
3
by reaction between VCl
3
and Tl(CCl
3
COO) in a molar ratio 1/3, V(CH
2
Cl—C
6
H
4
—COO)
3
by reaction between VCl
3
an CH
2
Cl—C
6
H
4
—COOTl in a molar ratio 1/3, V(CCl
3
COO)
2
Cl by reaction between VCl
3
and Tl(CCl
3
COO) in a molar ratio 1/2, V(CCl
3
CH
2
CH
2
COO)
3
by reaction between VCl
3
and CCl
3
CH
2
CH
2
COOTl in a ratio 1/3.
A third object of the present invention relates to a catalytic system for the (co)polymerization of &agr;-olefins consisting of:
(a) Vanadium complex having general formula (I),
(b) organo Aluminum derivative having general formula (II) AlR
n
X
m
, wherein R is a C
1
-C
20
alkyl group, X is chlorine or bromine, preferably chlorine, and n+m=3, with the exclusion of the compound having n=0,
(c) optionally a reactivator, preferably chlorinated.

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