Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Phosphorus or compound containing same
Reexamination Certificate
2000-06-23
2001-05-15
Padmanabhan, Sreeni (Department: 1621)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Phosphorus or compound containing same
C502S230000, C568S451000, C568S454000, C514S110000, C514S111000
Reexamination Certificate
active
06232263
ABSTRACT:
This invention pertains to certain novel catalyst systems comprising at least one chlorophosphite ligand compound in combination with a transition metal and the use of the catalyst system in the hydroformylation of various &agr;-olefins to produce aldehydes.
The hydroformylation reaction, also known as the oxo reaction, is used extensively in commercial processes for the preparation of aldehydes by the reaction of one mole of an olefin with one mole each of hydrogen and carbon monoxide. The most extensive use of the reaction is in the preparation of normal- and iso-butyraldehyde from propylene. The ratio of the amount of the normal aIdehyde product to the amount of the iso aldehyde product typically is referred to as the normal to iso (N:I) or the normal to branched (N:B) ratio. In the case of propylene, the normal- and iso-butyraldehydes obtained from propylene are in turn converted into many commercially-valuable chemical products such as, for example, n-butanol, 2-ethylhexanol, n-butyric acid, iso-butanol, neo-pentyl glycol, 2,2,4-trimethyl-1,3-pentanediol, the mono-isobutyrate and di-isobutyrate esters of 2,2,4-trimethyl-1,3-pentanediol. The hydroformylation of higher &agr;-olefins such as 1-octene, 1-hexene and 1-decene yield aldehyde products which are useful feedstocks for the preparation of detergent alcohols and plasticizer alcohols. The hydroformylation of substituted olefins such as allyl alcohol is useful for the production of other commercially valuable products such as 1,4-butanediol.
U.S. Pat. No. 3,239,566, issued Mar. 8, 1966, to Slaugh and Mullineaux, discloses a low pressure hydroformylation process using trialkylphosphines in combination with rhodium catalysts for the preparation of aldehydes. Trialkylphosphines have seen much use in industrial hydroformylation processes but they typically produce a limited range of products and, furthermore, frequently are very oxygen sensitive. U.S. Pat. No. 3,527,809, issued Sep. 8, 1970 to Pruett and Smith, discloses a low pressure hydroformylation process which utilizes triarylphosphine or triarylphosphite ligands in combination with rhodium catalysts. The ligands disclosed by Pruett and Smith, although used in many commercial applications, have limitations due to oxidative and hydrolytic stability problems. Since these early disclosures, numerous improvements have been made to increase the catalyst stability, catalyst activity and the product ratio with a heavy emphasis on yielding linear aldehyde product. A wide variety of monodentate phosphite and phosphine ligands, bidentate ligands such as bisphosphites and bisphosphines as well as tridentate and polydentate ligands have been prepared and disclosed in the literature. Notwithstanding the substantial progress which has been made in the area of hydroformylation catalyst systems and chemistry, there still exists a need to develop, more stable, less expensive and more selective hydroformylation catalysts.
We have discovered that chlorophosphite diester compounds are useful as ligands in catalyst systems for the conversion of olefins to aldehydes. The chlorophosphite ligands of the present invention can be substituted for, or used in combination with, known phosphite and/or phosphine ligands in a wide variety of catalyst systems utilizing a transition metal as the primary catalyst component. Thus, one embodiment of the present invention is a novel catalyst system comprising a combination of one or more transition metals selected from the Group VIII metals and rhenium and one or more chlorophosphite compounds (also known as chlorophosphonites) having the general formula
wherein R
1
and R
2
are aromatic hydrocarbyl radicals which contain a total of up to about 40 carbon atoms and wherein the ratio of gram moles chlorophosphite ligand to gram atoms transition metal is at least 1:1. The novel catalyst systems may be used in a wide variety of transition metal-catalyzed processes such as, for example, hydroformylation, hydrogenation, isomerization, hydrocyanation, hydrosilation, carbonylations, oxidations, acetoxylations, epoxidations, hydroamination, dihydroxylation, cyclopropanation, telomerizatons, carbon hydrogen bond activation, olefin metathesis, olefin dimerizations, oligomerizations, olefin polymerizations, olefin-carbon monoxide copolymerizations, butadiene dimerization and oligomerization, butadiene polymerization, and other carbon-carbon bond forming reactions such as the Heck reaction and arene coupling reactions. The catalyst systems comprising rhodium as the transition metal are especially useful for the hydroformylation of olefins to produce aldehydes and, therefore, are preferred.
A second embodiment of our invention concerns a novel catalyst solution comprising (1) one or more of the chlorophosphite ligands of formula (I), (2) rhodium and (3) a hydroformylation solvent. This embodiment comprises a solution of the active catalyst in which a carbonylation process such as the hydroformylation of an ethylenically-unsaturated compound may be carried out.
A third embodiment of the present invention pertains to a hydroformylation process utilizing the above-described catalyst systems and solutions. The process of the present invention therefore includes a process for preparing an aldehyde which comprises contacting an olefin, hydrogen and carbon monoxide with a solution of a catalyst system comprising rhodium and a chlorophosphite ligand of formula (I) wherein the mole ratio of phosphine ligand:rhodium is at least 1:1.
It is generally recognized in the art that the presence of halogens in hydroformylation catalysts normally reduces substantially the activity of the catalyst. The literature contains numerous references and citations in which halogens are identified at poisons in the rhodium catalyzed hydroformylation process. For example, Falbe (“New Syntheses with Carbon Monoxide” edited by J. Falbe, 1980, Springer-Verlag) on page 73 lists halogens as poisons for hydroformylation catalysts. U.S. Pat. Nos. 5,059,710, 4,595,753, 4,605,781 and 4,642,395 teach that halogen atoms generally are detrimental to the activity of hydroformylation catalyst systems. U.S. Pat. No. 4,871,878 discloses that halogens may be present in the organic structure of a ligand, but these halogen-containing substituents typically have the halogen located in a stable, non-hydrolyzable group, away from the phosphorus center and sufficiently far removed from the rhodium atom that no interactions can occur. For example, U.S. Pat. No. 4,871,878 teaches the use of halogen substituted tribenzylphosphine ligands except those cases where the chlorine, bromine or iodine are in the positions adjacent to the benzylic group.
Reactions of halophosphorus compounds with hydroxylic materials or water are well known in the chemical literature. Cotton and Wilkinson (“Advanced Inorganic Chemistry”, 3rd Edition, 1972, Wiley and Sons, pages 374-375) describe the phosphorus halides as materials which are hydrolyzed, sometimes violently, in the presence of water. Kosolapoff reported many years ago (“Organophosphorus Compounds”, 1950, Wiley and Sons, pages 180 to 199) that the halophosphites are unstable to heat, and react with water, alcohols, and phenols. Chlorophosphites have been characterized as “Rapidly hydrolyzed” and “Reacts violently with water” (“Dictionary Of Organophosphorus Compounds”, edited by Edmundson. 1988, Chapman and Hall, pages 144 and 149, entries C-00063 and C-00092). The reactions with the hydroxylic materials generate phosphoric acid esters as the initial product and hydrogen halides. Hydrogen halides have been described as poisons to many transition metal-catalyzed processes such as the hydroformylation reaction. Therefore, the presence of any phosphorus halide species in a hydroformylation reaction usually is deemed undesirable.
Contrary to the teachings of the prior art, we have found that the chlorophosphite ester compounds having the formula
function as effective ligands when used in combination with transition metals to form catalyst systems for the processes described hereinabove.
Puckette Thomas Allen
Tolleson Ginette Struck
Eastman Chemical Company
Gwinnell Harry J.
Padmanabhan Sreeni
Smith Matthew W.
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