Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1998-12-11
2001-01-16
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S451000
Reexamination Certificate
active
06175043
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for the preparation of linear aldehydes by hydroformylation of ethylenically unsaturated organic compounds in the presence of a catalyst system comprising a Group VIII metal and an organic ligand containing phosphorous having the structure P(OR)
2
-OR′O—P(OR)
2
or P(OR)
3
, where R and R′ are organic residues which may be the same or different and where the R or R′ contain at least one C9 to C40 aliphatic group positioned as a tail extending away from the primary ligand structure rendering the ligand lipophilic.
BACKGROUND OF THE INVENTION
The synthesis of an aldehyde by hydroformylation is known in the art. A catalyst for such a process is generally a soluble complex of a Group VIII transition metal having a phosphorus containing organic ligand. It is also known that the selection of the catalyst for the hydroformylation reaction has an influence on the rate and selectivity to the product aldehyde(s). Bidentate ligands are particularly preferred for their combination of reactivity and selectivity.
A number of patents teach structures of bidentate ligands for hydroformylation reactions that may be used for the production of aldehydes. U.S. Pat. No. 5,235,113 teaches a hydroformylation process in which an organic bidentate phosphite ligand containing two phosphorus atoms linked with an organic dihydroxyl bridging group is used with rhodium as a homogeneous hydroformylation catalyst.
Hydroformylation processes involving organic bidentate ligands containing two trivalent phosphorus atoms, in which the two phosphorus atoms are linked with a 2,2′-dihydroxyl-1,1′-binaphthalene bridging group, have been described in U.S. Pat. Nos. 4,769,498, 4,668,651, 5,113,022, 5,059,710, 5,264,616, and 4,885,401. Additional examples appear in WO-A-9303839 and WO-A-9518089.
With respect to the hydroformylation process, U.S. Pat. No. 4,148,830 teaches the use of high boiling condensation products of the process as the solvent in recycling the catalyst system; and U.S. Pat. No. 4,247,486 teaches the use of a gas recycle to control the liquid level in the reaction and to control the build-up of high boiling components in the process stream.
These prior patents teach catalyst structures and improvements in continuous processes for hydroformylation, but none address the problem of isolating product, byproduct and catalyst, one from the other. Yet, in all hydroformylation processes, the catalyst must be separated from the reaction products. In the case of hydroformylations such as the present invention, where the desired reaction product is an aldehyde, it has proved difficult to separate reaction products, particularly the higher boiling products and byproducts, from the catalyst system.
U.S. Pat. No. 5,648,554 to Mori et al., teaches separation of the hydroformylation catalyst precursor and the high boiling byproducts by extraction of this mixture in a polar solvent. This patent does not demonstrate the proposed process with the actual catalyst system used in hydroformylation, and neither does this patent make any clear teaching as to ligand structures that are necessary for the process of the patent to be workable.
The present invention provides a process by which the reaction products, including the high boiling products and byproducts, may be easily separated from the reaction catalyst system. In the present process the catalyst system may be readily separated from reaction products and recycled for use in the process, thus providing longer active catalyst system productivity.
SUMMARY OF THE INVENTION
The present invention provides a process for preparation of a linear aldehyde comprising reacting an ethylenically unsaturated compound by hydroformylation in the presence of a catalyst system composed of a Group VIII metal and an organic phosphite ligand in a two phase reaction solvent. The organic ligand is one containing phosphorous having the structure (PR
2
)
n
R′ where n is an integer from 1 to 2, R and R′ are organic residues which may be the same or different and where the R or R′ contain at least one C9 to C40 aliphatic group positioned as a tail extending away from the primary ligand structure rendering the ligand lipophilic.
The preferred ligand is a bidentate phosphite ligand, P(OR)
2
-OR′O—P(OR)
2
or P(OR)
3
, where, containing at least one C9 to C40 aliphatic group positioned on the backbone or side arm ring structures of the ligand. The hydroformylation reaction solvent is preferred to be a two phase mixture of an organic compound having from 5 to 20 carbon atoms and polar solvent, but the present invention also applies to single phase reaction mixtures.
The present process may be represented as a series of process steps comprising:
(a) reacting in a reaction solvent to form a reaction mixture the ethylenically unsaturated compound in the presence of a catalyst system composed of a Group VIII metal and organic phosphite ligand containing phosphorous having the structure P(OR)
2
-OR′O-P(OR)
2
R and R′ are organic residues which may be the same or different and where the R or R′ contain at least one C9 to C40 aliphatic group positioned as a tail extending away from the primary ligand structure rendering the ligand lipophilic;
(b) adding a non-polar solvent to the reaction mixture to form two phases, one a polar phase predominately formed from the reaction products and one formed predominately from the non-polar solvent and the catalyst system such that the reaction products including the high boiling reaction products of the hydroformylation remain in the polar phase and the catalyst system is partitioned substantially into the non-polar phase; and
(c) separating the two phases and isolating the reaction products from the polar phase and the catalyst from the non-polar phase.
The preferred ligand a bidentate phosphite ligand having the structure P(OR)
2
-OR′O—P(OR)
2
where R and R′ are organic residues and where the R or R′ contain at least one C9 to C40 aliphatic group positioned as a tail extending away from the bridging group (R′) or the side arms (R).
Volatiles may be removed in the present process from the reaction mixture of step (a) before the addition of the non-polar solvent of step (b). Also in the present process steps (a) and (b) may be combined and such that the hydroformylation is carried out in a two phase reaction solvent.
The present process may be run as a batch or a continuous process. In a continuous process the recovered catalyst is returned to step (a) and the steps are repeated.
The present process also provides an improved hydroformylation process for preparation of a linear aldehyde from a reaction mixture containing an ethylenically unsaturated compound and a catalyst system composed of a Group VIII metal and a bidentate organic phosphite ligand having two trivalent phosphorous atoms wherein the ethylenically unsaturated compound also functions as reaction solvent, the improvement comprising: forming the catalyst system from a ligand containing at least one C9 to C40 aliphatic group positioned on the backbone or side arm ring structures of the ligand and following hydroformylation of the ethylenically unsaturated compound adding to the reaction mixture a two phase solvent mixture consisting of a polar and a non-polar components so that the reaction products of the hydroformylation are extracted into the polar phase of the solvent mixture and the catalyst system remains substantially in the non-polar phase of the solvent mixture.
Preferred structures for the phosphite ligands of the present invention are Ligands I-IX. As noted below the basic structure for Ligands I, II and III is the structure on the left (structure A); the basic structure for Ligands IV to IX is the structure on the right (structure B)
wherein structures A for Ligands I to III and structures B for Ligands IV to IX, Ligand I, R
1
is (CH
2
)
9
CH
3
and R
2
is H; Ligand II, R
1
is (CH
2
)
9
CH
3
and R
2
is CO(CH
2
)
8
CH
3
; Ligand III
E. I. Du Pont de Nemours and Company
Padmanabhan Sreeni
LandOfFree
Process of preparation of linear aldehydes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process of preparation of linear aldehydes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process of preparation of linear aldehydes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2484621