Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Patent
1997-11-10
1999-03-02
Teskin, Fred M.
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
502 62, 502 63, 502 65, 502103, 502104, 502107, 502108, 502118, 502120, 502132, 526129, 526156, 526164, 526901, C08F 444
Patent
active
058771093
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a novel catalyst, to the production thereof and to the use thereof for the polymerisation of conjugated dienes, in particular butadiene, in the gas phase.
Polybutadiene with an elevated proportion of cis-1,4 units has long been produced on a large industrial scale and used for the production of tyres and other rubber articles. Polymerisation is performed in this connection in the liquid phase using the most various catalyst systems. A particularly advantageous catalyst system for the production of polybutadiene with an elevated proportion of cis-1,4 units is described in European Patent 11 184. The catalyst system which is described therein and used for solution polymerisation of butadiene consists, for example, of a rare earth carboxylate, an aluminiumtrialkyl and/or alkylaluminium hydride and a further Lewis acid.
Polymerising conjugated dienes in solution has the disadvantage that when the unreacted monomer and the solvent are separated from the formed polymer, low molecular weight compounds may escape to the environment in exhaust air and effluent and must thus be appropriately disposed of.
It is also known to polymerise conjugated dienes without adding solvents in the liquid monomers. However, such a process has the disadvantage that a large quantity of heat is liberated on complete polymerisation, which is difficult to control and thus constitutes a certain potential hazard. Moreover, very high viscosities occur which require special apparatus. Here too, there is an environmental impact when the polymers are separated from the monomers.
In recent years, the gas phase process has proved particularly advantageous, particularly for the production of polyethylene and polypropylene and has become widely used industrially. The environmental advantages of the gas phase process are in particular that no solvents are used and emissions and effluent contamination may be reduced.
There has hitherto been no known process for the direct gas phase polymerisation of conjugated dienes, in particular of butadiene to yield polymers with an elevated cis content. One reason for this may be that the Ziegler-Natta catalysts based on titanium, cobalt, nickel or neodymium which are used for the solution polymerisation of conjugated dienes are not straightforwardly suitable for gas phase polymerisation, in particular due to their low productivity, i.e. the small quantity of polymer which may be produced with a certain quantity of catalyst. Thus, due to its rapidly falling activity when used in gas phase polymerisation, the catalyst described in EP 11 184 is virtually completely unsuitable to polymerise conjugated dienes, in particular butadiene, in the gas phase to yield polymers with an elevated proportion of cis-1,4 units (see comparative test).
A catalyst system which allows the polymerisation of conjugated dienes, in particular butadiene, in industrially useful yields, but still merits further improvement was described in German Patent Application P 43 34 045.
The object of the present invention is to provide improved catalysts for the polymerisation of conjugated dienes, in particular butadiene, in the gas phase which make it possible to produce good yields of polybutadiene with an elevated proportion of cis-1,4 units combined with an elevated molecular weight.
The present invention thus provides a catalyst comprising earth coordination compound with diketones (III) of the following formulae: ##STR1## B) an alumoxane of the formulae (IV) to (V): ##STR2## wherein, in the formulae, M means a trivalent rare earth element with an atomic number of 57 to 71, atoms and greater than 10 m.sup.2 /g (BET) and a pore volume of 0.30 to 15 ml/g, wherein the molar ratio of component A) to component B) is 1:1 to 1:50000 and 0.1 mmol to 1 mol of component A) are used per 100 g of component C).
In component A) of the catalyst, M means a trivalent rare earth element with the atomic numbers identified in the periodic system of 57 to 71.
Preferred compounds are those in which M means lanthanum, cerium, praseodymium
REFERENCES:
patent: 4260707 (1981-04-01), Sylvester et al.
patent: 4575538 (1986-03-01), Hsieh et al.
patent: 4689368 (1987-08-01), Jenkins
patent: 5021379 (1991-06-01), Martin et al.
patent: 5428119 (1995-06-01), Knauf et al.
English Translation of International Preliminary Examination Report Dated Dec. 19, 1996.
Eberstein Christopher
Garmatter Birgit
Marquardt Peter
Reichert Karl-Heinz
Sylvester Gerd
Bayer AG
Teskin Fred M.
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