Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Phosphorus or compound containing same
Reexamination Certificate
2000-04-10
2001-09-18
Lambkin, Deborah C. (Department: 1626)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Phosphorus or compound containing same
C549S273000
Reexamination Certificate
active
06291390
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a catalyst obtained from phosphinoalkyl-functionalized polystyrene, in accordance with the first patent claim and a method for producing &dgr; lactone according to the preamble to the third patent claim.
DESCRIPTION OF THE RELATED ART
The use of phosphinoalkyl-functionalized polystyrene for producing a catalyst that catalyzes conversions of 1,3-butadiene with nucleophiles is known from the reference Kaneda et al. “Selective Telomerization of Butadiene with Various Nucleopphiles Catalyzed by Polymer-Bo- and Palladium (0) Complexes,” J. Org. Chem. 1981, 46, 2356-2362.
The article by Stephan Pitter, Eckhard Dinjus, Beate Jung and Helmar Gorlis: “PHOSPHINOLALKYLNITRILE: SYNTHESE UND KOORDINATIONS-VERHALTEN AN PALLADIUMZENTREN [Phosphinoalkyl Nitriles: Synthesis and Coordination Behavior on Palladium Centers],” published in the magazine Naturforsch. 51b, pp 934-946 (1996), dicloses that the synthesis of the &dgr;-lactone (2-ethylidene-hepta-6-en-5-olide) is catalyzed with high selectivity through Pd(0) complexes with wide-spreading phosphine ligands. A phosphinoalkyl nitrile of the type R
2
P—(CH
2
)n—CN (n=1) is used as a preliminary stage for displaying the catalysts, wherein chain lengths with n>4 are preferred for steric reasons. The phosphinoalkyl nitrile is converted with a palladium (II)-compound, e.g. (&eegr;
5
-cyclopentadienyl) (&eegr;
3
-allyl) palladium. The synthesis of the &dgr; lactone thus occurs with a homogeneous catalysis and the use of a solvent.
European Patent 0 234 668 A2 discloses the production of &dgr; lactone by converting 1,3-butadiene with carbon dioxide in a solvent, in the presence of palladium or a palladium compound, an amine and a bidentate ligand with the general formula R
1
R
2
MRMR
3
R
4
, wherein M, for example, is phosphor, R is an organically bridging group with 3C-atoms, and R
1-4
are substituted or non-substituted hydrocarbon groups.
German Patent 28 38 610 A also discloses a method for producing &dgr; lactone from 1,3 butadiene and carbon dioxide. With this method, the two base materials are converted in the presence of a catalyst in the form of a palladium phosphine complex with the formula Pd [P(R)
3
]
x
, wherein x represents a whole number from 2 to 4 and R represents an alkyl residue or a cycloalkyl residue with up to 8 carbon atoms or a phenyl residue. The residues can also be substituted and can be the same or different. The process temperature provided is 20° to 150° C. and the total pressure 10 to 500 bar. The catalyst can be produced in situ by adding its educts, a palladium compound and a phosphine, to the reaction medium.
The known methods with homogeneous catalysis have several disadvantages. The catalyst cannot be recaptured, so that the expensive base materials must be provided again for each conversion. In addition, the catalyst and its decomposition products contaminate the desired end product.
It is the object of the invention to remove these disadvantages and to use a catalyst for the conversion of butadiene with carbon dioxide, which can be recaptured easily and does not contaminate the end product. In addition, another method for producing &dgr; lactone is to be suggested.
SUMMARY OF THE INVENTION
This object is accomplished by providing a catalyst, obtained through a conversion of phosphinoalkyl-functionalized polystyrene with (&eegr;
5
-cyclopentadienyl)(&eegr;
3
-allyl) palladium. Preferably, the catalyst is obtained through a conversion with (diisopropylphosphino) methyl-functionalized polystyrene. The object of the present invention is likewise accomplished by providing a method for producing &dgr; lactone, for which 1,3-butadiene is converted with carbon dioxide in the presence of the catalyst, wherein the catalyst used is the product of the reaction of (&eegr;
5
-cyclopentadienyl)(&eegr;
3
-allyl) palladium with a compound containing a phosphino group, characterized in that the compound containing a phosphino group is a phosphinoalkyl-functionalized polystyrene.
According to the invention, an optional phosphinoalkyl-functionalized polystyrene is used for producing the catalyst, wherein it is not important at which intervals the phenyl groups suspended from the polymer skeleton are substituted. A straight-chain or a branched alkyl residue, for example with 2 to 8 carbon atoms, with a cycloalkyl residue or an aryl residue can be used for a phosphino group substitution. Preferred is the substitution with an isopropyl residue.
The phosphinoalkyl-functionalized polystyrene (2) can be produced, for example, with the following reaction of commercially available, partially chloromethylated polystyrene (1):
where R is an alkyl, aryl or cycloalkyl, preferably isopropylene, and n and m represent identical or different whole numbers ranging from 1 to 5.
For the production of the catalyst, the phosphinoalkyl-functionalized polystyrene is converted with (&eegr;
5
-cyclopentadienyl)(&eegr;
3
-alkyl) palladium (3).
The allyl can be substituted, e.g. with allyl chains having a length of 1 to 10 C-atoms. The cyclopentadienyl residue can be substituted in the same way. However, non-substituted allyl (C
3
H
5
) is preferred. The conversion can take place “in situ” in the presence of the reactants or can occur prior to the reaction. The second alternative opens up the option, which is not provided in prior art, of using a pre-prepared catalyst.
The reactor is filled in the presence of a protective gas atmosphere (nitrogen, argon). The reaction is carried out without the presence of air and moisture, in a carbon dioxide atmosphere and at a temperature of between 25° and 90° C., preferably at 60° to 70° C. and a pressure of 5 to 100 bar, preferably at 20 to 30 bar. The reaction takes from 2 to50 h.
The catalyst prepared “in situ” as well as the pre-prepared catalyst can be used repeatedly. The activity of the pre-prepared catalyst is initially higher, but drops after several cycles to values that are comparable to those of the in situ generated catalyst. The selectivity in the formation of 2-(E)-ethylidene-hepta-6-en-5-olide is between 57 and 71% for reaction times that are not excessively long.
The alternatively accessible products according to Pitter et al and the literature cited therein (C
17
-ester, &ggr; lactone etc.) can also be produced with the catalyst system described therein (for example with noticeably longer reaction times).
The invention offers a series of advantages: The catalyst can be easily separated from the reaction mixture through filtration and can be regenerated by simply washing and drying it. Alternatively, the catalyst can be provided in a strainer. With respect to the use of the expensive butadiene, it shows a high selectivity in the range between 50 and 75%, so that butadiene losses caused by conversion to by-products are low. The end product is not contaminated with the catalyst or its decomposition products. The method can thus be carried out continuously.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the following, the invention is explained in further detail with the aid of test examples.
In all cases, the catalyst used was (&eegr;
5
-cyclopentadienyl)(&eegr;
3
-allyl) palladium. The solvent used was acetonitrile. The reaction conditions were 16 hours at approximately 70° C.
All experiments were carried out in a 250 ml stainless steel autoclave, equipped with gas inlet and gas outlet valves, manometer, inside thermometer, magnetic stirring rods and heated magnetic stirrer. The specified reaction temperatures were adjusted by means of an oil bath. In order to be able to compare the individual experiments within a series, with respect to the selectivity to &dgr; lactone, the reaction times were selected such that a complete conversion of butadiene has not yet taken place.
REFERENCES:
patent: 4506030 (1985-03-01), Jones
patent: 5498582 (1996-03-01), Krause et al.
patent: 5525566 (1996-06-01), Keim et al.
patent: 28 38 610 A1 (1979-03-01), None
patent: 0 234 668 A2 (1987-09-01), None
Stephan Pitter, et al, “Phosphinoalkyl
Dinjus Eckhard
Holzhey Nancy
Pitter Stephan
Forschungszentrum Karlsruhe
Kunitz Norman N.
Lambkin Deborah C.
Venable
Wells Ashley J.
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