Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-11-17
2002-08-20
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S451000, C556S014000
Reexamination Certificate
active
06437192
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
“Not Applicable”
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
“Not Applicable”
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the use of certain bisphosphonite ligands in the presence of a Group VIII metal to catalyze the hydroformylation of C
4
to C
20
conjugated dienes to alkenals.
2. Description of the Related Art
The hydroformylation of alkadienes to produce alkenals, for example the hydroformylation of butadiene to pentenals, is generally known. Pentenals are potential intermediates to a variety of useful compounds. Pentenals may be oxidized and optionally esterified to pentenoic acids or methyl pentenoates, which in turn can be hydroformylated to 5-formylvaleric acid or 5-formylvalerates. 5-Formylvaleric acid and 5-formylvalerates are useful intermediates in the production of epsilon caprolactam. Currently processes for the direct production of pentenoic acids or methyl pentenoates by carbonylation of butadiene may require high temperatures; i.e., greater than 120° C. An advantage of hydroformylation of butadiene to pentenals is that it requires much lower temperatures; i.e., less than 100° C.
Most processes to produce pentenoic acid or pentenoate esters involve the use of halide promoted catalysts such as described in U.S. Pat. Nos. 5,250,726 and 5,288,903. These processes have the disadvantage that they use high concentrations of hydrohalogenic acids and other rigorous conditions, which necessitate cost-increasing measures in connection with safety and the corrosion of the equipment. In U.S. Pat. No. 5,028,734 issued Jul. 2, 1991, a process is described for the selective carbonylation of a conjugate diene by contacting with carbon monoxide in the presence of a hydroxyl group-containing compound such as methanol. This catalyst system is less corrosive than the process that is described in U.S. Pat. Nos. 5,250,726 and 5,288,903 but still has the disadvantage of requiring the use of a catalyst consisting of palladium, a bidentate phosphine and an acid to catalyze the transformation of butadiene to pentenoate esters. The main disadvantage of the presence of an acid is its reactivity towards the alcohol and the bidentate phosphines used in the process. Alcohols will react with the acid promoter to produce esters and phosphines will be converted to phosphonium salts. The combination of these two factors renders the invention described in U.S. Pat. No. 5,028,734 non-practical from an industrial point of view.
Pentenals may be alternatively hydrogenated to pentenols, which upon hydroformylation give hydroxyhexanals. 6-Hydroxyhexanal is a useful intermediate in the production of epsilon caprolactone.
Pentenals may be alternatively hydroformylated to dialdehydes, including adipaldehyde. Adipaldehyde is a valuable intermediate which is potentially useful in the production of compounds such as adipic acid (by oxidation), hexamethylenediamine (by reductive amination), and 1,6-hexanediol (by hydrogenation). Production of adipaldehyde by hydroformylation of pentenals would be a desirable improvement over current processes based on the oxidation of cyclohexane because it is based on butadiene, a less expensive feedstock.
Although a variety of complexes of bis(phosphorus) ligands with rhodium catalyze the hydroformylation of butadiene, the selectivity for 3- and 4-pentenals is low for many of them. Various publications in the 1970's and 1980's, describe hydroformylation of butadiene catalyzed by rhodium complexes with monodentate phosphines (For example, Fell, B. and W. Rupilius
Tetrahedron Lett.
1969, 2721-3; Fell, B. and W. Boll
Chem.
-
Ztg.
1975, 99, 452-8; Fell, B., W. Boll, and J. Hagen
Chem.
-
Ztg.
1975, 99, 485-92; Fell, B. and H. Bahrmann
J. Mol. Catal.
1977, 2, 211-18). These systems yield primarily valeraldehyde because the rhodium/phosphine catalysts are also very efficient catalysts for hydrogenation. Van Leeuwen reported that under mild conditions (95° C. and 175 psi (1.3 MPa) 1:1 H
2
/CO) rhodium complexes of bidentate phosphines also yield primarily valeraldehyde (European Patent No. EP33554 A2, Van Leeuwen, P. W. N. M. and C. F. Roobeek
J. Mol. Catal.
1985, 31, 345-53). Recently, however, Ohgomori reported that under more vigorous conditions (100° C. and 1300 psi (8.9 MPa) 1:1 H
2
/CO) these catalysts give 3- and 4-pentenals (Ohgomori, Y., Suzuki, N., and Sumitani, N.
J. Mol. Catal.
1998, 133, 289-291). However, under these conditions the pentenals undergo further hydroformylation to a mixture of dialdehydes, lowering the yield. It has also been reported that hydroformylation of butadiene under biphasic conditions using the sulfonated phosphine P(C
6
H
4
-3-SO
3
Na)
3
yields 3-pentenal (B. Fell, P. Hermanns, and H. Bahrmann,
J. Prakt. Chem.,
340 (1998), pp. 459-467, German Patent No. DE 19532394).
A recent series of patents (U.S. Pat. Nos. 5,312,996, 5,817,883, 5,821,389, European Patent No. 872,469, European Patent No. 872,483, U.S. Pat. Nos. 5,892,127, 5,886,237, and European Patent No. 872,483) discloses a hydroformylation process in which rhodium complexes of bidentate phosphite ligands catalyze the hydroformylation of butadiene to 3-pentenals. U.S. Pat. No. 5,710,344 discloses the use of rhodium complexes of bidentate phosphorus ligands wherein the ligand contains a bridging group bonded through P—O bonds to a pair of trivalent phosphorus atoms with the other two bonds to each phosphorus being either a pair of P—N bonds (phosphorodiaminites), a pair of P—C bonds (phosphinites) or one P—N and one P—C bond (phosphoroaminites).
These prior art processes using rhodium complexes of bidentate phosphorus ligands to produce 3-pentenal from butadiene have various disadvantages. For example, the isolation of 3-pentenal in these systems is complicated by side reactions such as isomerization to 2-pentenal, reduction to valeraldehyde, and further hydroformylation to a mixture of dialdehydes. Thus, these catalysts do not give high selectivity to 3-pentenal at high conversions of butadiene. For example, the highest selectivity reported for a rhodium complex of a bis(phosphite) ligand is 84% at 37% conversion of butadiene (U.S. Pat. No. 5,886,237). The bis(phosphinite) ligands disclosed in U.S. Pat. No. 5,710,344 disclose up to 95% selectivity at 95% conversion of butadiene, but only in the presence of greater than 5 equivalents of the bis(phosphinite) ligand.
Although bidentate phosphonite ligands are not commonly used in catalysis, they have been employed as catalysts for a variety of transformations, including nickel-catalyzed cyclotrimerization of alkynes (
Heterocycles,
1997, 44, 443-457), nickel- and palladium-catalyzed alkylations and cross couplings (
J. Org. Chem.
1995. 60, 2016-2;
J. Chem. Soc., Perkin Trans.
1, 1995, 17, 2083-96), nickel-catalyzed hydrocyanation of olefins (U.S. Pat. No. 5,523,453), and rhodium-catalyzed enantioselective hydrogenation of olefins (Reetz, M., Gosberg, A., Goddard, R., Kyung, S.-H.
Chem. Commun.
1998, 19, 2077-2078).
Bidentate phosphonite ligands based on a ferrocene backbone have been disclosed in U.S. Pat. No. 5,817,850 and
Chem. Commun.
1998, 19, 2077-2078. The bidentate phosphonites described in these publications have biphenol or binaphthol derived terminal groups that are bridged. U.S. Pat. No. 5,817,850 claims a hydrocarbonylation reaction of an alkene with carbon monoxide and hydrogen to form an aldehyde which is catalyzed by a transition metal complex of the bridged terminal group containing ferrocene bis(phosphonite) disclosed therein.
BRIEF SUMMARY OF THE INVENTION
In view of the above prior art, the present invention involves the use of catalyst compositions based on certain phosphonite ligands that structurally involve a ferrocene moiety between a pair of phosphorous atoms and a Group VIII metal or Group VIII metal compound in the hydroformylation of alkadienes (i.e., acyclic hydrocarbons with two double bonds) to produce alkenals (i.e., linear ethylenically unsaturated aldehydes).
The invention provi
E. I. du Pont de Nmeours and Company
Padmanabhan Sreeni
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