Bisphosphite compounds and their metal complexes

Details Bisphosphite compounds and their metal complexes Bisphosphite compounds and their metal complexes

2001-10-29

2003-05-27

Vollano, Jean F. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Phosphorus esters

C556S013000, C558S077000

Reexamination Certificate

active

06570033

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to bisphosphites and their metal complexes, and the preparation and the use of the bisphosphites as ligands in catalytic reactions.
2. Description of the Background
The reaction between olefin compounds, carbon monoxide and hydrogen in the presence of a catalyst to form aldehyde product having one more carbon atom than the carbon atom content of the starting olefin is known as hydroformylation (the oxo process). The catalysts used in these reactions are frequently compounds of transition metals of Group VIII of the Periodic Table of the Elements, in particular compounds of rhodium and of cobalt. In comparison with catalysis using cobalt compounds, hydroformylation using rhodium compounds generally offers the advantage of higher selectivity and is thus usually more economical. In rhodium-catalyst hydroformylation, use is usually made of complexes comprising rhodium and preferably trivalent phosphorus compounds as ligands. Examples of known ligands are compounds from the classes of the phosphines, phosphites and phosphonites. A good review of the hydroformylation of olefins may be found in B. CORNILS, W. A. HERRMANN, “
Applied Homogeneous Catalysis with Organometallic Compounds”
Vol. 1&2, VCH, Weinheim, New York, 1996.
Each catalyst system (cobalt or rhodium) has its specific advantages. For this reason, different catalyst systems may be used depending on the starting material and target product, as the following examples show. When rhodium and triphenylphosphine are employed, &agr;-olefins can be hydroformylated at relatively low pressures. An excess of triphenylphosphine is generally used as phosphorus-containing ligand, and a high ligand/rhodium ratio is necessary to increase the selectivity of the reaction to the commercially desired n-aldehyde product.
U.S. Pat. Nos. 4,694,109 and 4,879,416 describe bisphosphine ligands and their use in the hydroformylation of olefins at low synthesis gas pressures. Particularly in the hydroformylation of propane, ligands of this type achieve high activities and high n/i selectivities. WO 95/30680 discloses bidentate phosphine ligands and their use in catalysis, including hydroformylation reactions. Ferrocene-bridged bisphosphines are described as ligands for hydroformylation reactions in, for example, the U.S. Pat. Nos. 4,169,861, 4,201,714 and 4,193,943.
The disadvantage of bidentate phosphine ligands is the relatively high cost of preparing them. It is therefore often not economically viable to use such systems in industrial processes.
Rhodium-monophosphite complexes are suitable catalysts for the hydroformylation of branched olefins having internal double bonds, but the selectivity to terminally hydroformylated compounds is low. EP 0 155 508 discloses the use of bisarylene-substituted monophosphites in the rhodium-catalyst hydroformylation of sterically hindered olefins, e.g. isobutene.
Rhodium-bisphosphite complexes catalyze the hydroformylation of linear olefins having terminal and internal double bonds, forming predominantly terminally hyroformylated products, while branched olefins having internal double bonds are reacted to only a small extent. On coordination to a transition metal center, these phosphites provide catalysts having increased activity, but the operating life of these catalysts systems is unsatisfactory because of, inter alia, the hydrolysis sensitivity of the phosphite ligands. Considerable improvements have been achieved by use of substituted bisaryl diols as starting materials for the phosphite ligands, as described in EP 0 214 622 and EP 0 472 071. According to the literature, the rhodium complexes of these ligands are extremely active hydroformylation catalysts for a-olefins. U.S. Pat. Nos. 4,668,651, 4,748,261 and 4,885,401 describe polyphosphite ligands by means of which c-olefins and also 2-butene can be converted highly selectively to the terminally hydroformylated products. Bidentate ligands of this type have also been used for the hydroformylation of butadiene (U.S. Pat. No. 5,312,996).
Although the bisphosphites mentioned are very good complexing ligands for rhodium hydroformylation catalysts, the need continues to exist for bisphosphites of improved effectiveness.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a bisphosphite ligand for the preparation of olefin hydroformylation catalysts of improved effectiveness.
Briefly, this object and other objects of the present invention as hereinafter will become more readily apparent can be attained by a bisphosphite of the formula I:
wherein:
R
1
, R
2
, R
3
and R
4
are each hydrogen, an aliphatic, alicyclic, aliphatic-alicyclic, aromatic, aromatic—aromatic, aliphatic-aromatic hydrocarbon or heterocyclic or aliphatic-heterocyclic radical having from 1 to 50 carbon atoms, F, Cl, Br, I, —CF
3
, —OR
7
, —COR
7
, —CO
2
R
7
, —CO
2
M, —SR
7
, —SOR
7
, —SO
3
R
7
, —SO
3
M, —SO
2
NR
7
R
8
, NR
7
R
8
, N═CR
7
R
8
, NH
2
, where R
1
to R
4
are identical or different and may be covalently linked to one another;
R
7
and R
8
are each hydrogen, a substituted or unsubstituted, aliphatic or aromatic hydrocarbon radical having from 1 to 25 carbon atoms, and may be identical or different;
M is an alkali metal, alkaline earth metal, ammonium or phosphonium ion;
Q is a substituted or unsubstituted divalent aliphatic, alicyclic, aliphatic-alicyclic, aromatic—aromatic, aromatic, aliphatic-aromatic hydrocarbon or heterocyclic or aliphatic-heterocyclic radical having from 1 to 50 carbon atoms; and in open-chain structural elements, one or more methylene groups may be replaced by oxygen and/or sulfur and/or NR
1
and/or NH and/or one or more CH groups may be replaced by nitrogen.
W and X are each a substituted or unsubstituted aliphatic, alicyclic, aliphatic-alicyclic, aromatic, aromatic—aromatic, aliphatic-aromatic hydrocarbon, heterocyclic or aliphatic-heterocyclic radical having from 1 to 50 carbon atoms which may be identical or different or covalently linked to one another.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In formula I above, in any given embodiment of the bisphosphite compound, two of the radicals R
1
to R
4
in the formula I may be benzofused, i.e. R
1
and R
2
, R
2
and R
3
or R
3
and R
4
may be linked to one another via an aromatic ring. It is thus possible to prepare three isomers which can be used either separately or together as a ligand system. The bisphosphite of formula I can therefore also be in the forms illustrated by formulae II, III and IV as follows:
The definitions of radicals R
1
to R
6
correspond to the definitions of R
1
to R
4
defined for formula I. It is possible for these radicals to be once again covalently linked to one another or benzofused.
Specific embodiments of the bisphosphites of the invention are bisphosphites of the formulae V, VI and VII as follows:
wherein W and X are each substituted or unsubstituted an aliphatic, alicyclic, aliphatic-alicyclic, aromatic, aromatic—aromatic, aliphatic-aromatic hydrocarbon, heterocyclic or aliphatic-heterocyclic radical having from 1 to 50 carbon atoms, X and W may be identical or different or may be covalently linked to one another and R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and R
8
and Q are as defined above, provided that when the phosphite oxygens linked to W and X are each linked to an aromatic ring then they are not linked to the same aromatic ring.
R
9
, R
10
, R
11
, R
12
, R
13
, R
14
, R
15
and R
16
are each hydrogen or an aliphatic, alicyclic, aliphatic-alicyclic, aromatic, aromatic—aromatic, aliphatic-aromatic hydrocarbon, heterocyclic or aliphatic-heterocyclic radical having from 1 to 50 carbon atoms, F, Cl, Br, I, —CF
3
, —OR
25
, —COR
25
, —CO
2
R
25
, —CO
2
M, —SR
25
, —SO
2
R
25
, —SOR
25
, —SO
3
R
25
, —SO
3
M, —SO
2
NR
25
R
26
, NR
25
R
26
, N═CR
25
R
26
, NH
2
, where R
9
to R
16
are identical or different and may be covalently linked to one another.
M is an alkali metal, alkaline earth metal, ammonium or phosphonium io

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