Hydroformylation processes for the production of oxygenated products, particularly aldehydes and/or alcohols, by the reaction of an olefinic feedstock with carbon monoxide and hydrogen at elevated temperatures and pressures in the presence of hydroformylation catalysts, are well known. The alcohols and/or aldehydes that are produced in these processes generally correspond to the compounds obtained, in the hydroformylation reaction, by the addition of a carbonyl or carbinol group to an olefinically unsaturated carbon atom in the feedstock with simultaneous saturation of the olefin bond.

A hydroformylation catalyst is selected according to the particular oxygenated products which are required from a particular olefinic feedstock. Thus, the hydroformylation catalyst may typically be a phosphine and/or phosphite ligand modified rhodium (Rh) or cobalt (Co) homogeneous catalyst. Examples of such catalysts are triphenyl phosphine ligands used with rhodium, and alkyl phosphine ligands used with cobalt. Specific examples of the latter are trialkyl phosphines and bicyclic tertiary phosphines such as 9-phosphabicyclo [3. 3. 1] nonane and 9-phosphabicyclo [4. 2. 1] nonane represented by formulas (I) and (II) respectively:

The ligands I and 11 are available commercially, as a mixture, under the collective chemical name eicosyl phoban ('EP').

A disadvantage of Co catalysed hydroformylation processes is the formation of branched side products, such as alkyl branched alcohols and alkyl branched aldehydes, where the alkyl branching is greater than methyl branching. These branched products not only impact negatively on the design of commercial processes but furthermore decrease the yield of the desirable and commercially valuable linear alcohol/aldehyde and/or monomethyl branched alcohol/aldehyde products from such a process.

It is hence an object of this invention to provide a process for producing oxygenated products from an olefinic feedstock by using a hydroformylation catalyst, whereby the selectivity of the catalyst to produce a combination of linear and monomethyl branched products is enhanced by using a specific catalyst phosphine ligand. The improved catalyst of the invention offers advantages for the production of a custom methyl-branched linear alcohol for application in biodegradable surfactants.

Thus, according to a first aspect of the invention, there is provided a process for producing oxygenated products from an olefinic feedstock, which process includes reacting, in a hydroformylation reaction stage, an olefin feedstock with carbon monoxide and hydrogen at an elevated reaction temperature and at a superatmospheric reaction pressure in the

presence of a hydroformylation catalyst comprising a mixture or combination of a metal, M, where M is cobalt (Co), rhodium (Rh), ruthenium (Ru) or palladium (Pd); carbon monoxide; hydrogen; and at least one bicyclic tertiary phosphine having two cyclic structures and a ligating phosphorus atom, with the ligating phosphorus atom forming part of the largest ring structure of the molecule, and with fewer than two hydrocarbon substituents being present on the carbon atoms of the cyclic structures of the molecule, to produce oxygenated products comprising aldehydes and/or alcohols.

While, in the hydroformylation catalyst, the metal, M, may be any one of cobalt, rhodium, ruthenium or palladium, cobalt is preferred.

In particular, the bicyclic tertiary phosphine of the hydroformylation catalyst may be a [3.3. 1] phosphabicyclononane represented by formula (ici) : where is an alkyl, branched alkyl, cycloalkyl, or aryl group.

The hydroformylation catalyst may instead comprise a plurality of the bicyclic tertiary phosphines in the form of a mixture of bicyclic tertiary phosphine isomers. Thus, the hydroformylation catalyst may comprise a mixture of isomers of the [3.3. 1] phosphabicyclononane represented by formula (III). One of the isomers of the phosphabicyclononane of formula (III) may be [3.2. 2] phosphabicyclononane represented by formula (IV) : where is an alkyl, branched alkyl, cycloalkyl, or aryl group.

In one embodiment of the invention, in the hydroformylation catalyst, Ri of the phosphabicyclononane may, in particular, be a linear C2 to C20 hydrocarbon chain.

The family of ligands of formulas (III) and (IV) is named VCH (as these ligands are vinylcyclohexene derived); thus, each ligand can be denoted 'VCH', together with a suffix corresponding to the carbon number of Ri.

In one embodiment of the invention, the ligand may be VCH-C12. Thus, VCH-C12 will be represented by the formulas V and VI, where R, is C12H25.

However, in other embodiments of the invention, in the hydroformylation catalyst, Ri of the phosphabicyclononane may be a cycloalkyl, a branched alkyl or an aryl group.

The Applicant has found that, in certain applications, a reduction in the degree of hydrogenation and/or an increase in the reaction rate, can be achieved when the number of carbon atoms in the hydrocarbon chain (when R1 is a hydrocarbon chain) and/or when Ri is a cycloalkyl, a branched alkyl or an aryl group rather than a linear alkyl group or chain.

When Ri is a cycloalkyl group, it may be cyclohexyl.

When Ri is a branched alkyl group, it may be 2,4, 4-trimethylpentyl.

When Ri is an aryl, it may be phenyl.

The bicyclic tertiary phosphine can be obtained by reacting a hydrocarbylphosphine with a mono-or un-substituted vinylcyclohexene.

The hydrocarbylphosphine may be of the general formula R-PH2, wherein R is an alkyl, a branched alkyl, cycloalkyl or an aryl radical to which the phosphorus atoms is linked by means of a primary, secondary or tertiary carbon atom. The reaction is typically carried out in the presence of a free radical initiator as a catalyst. Thus, the hydrocarbylphosphine and vinylcyclohexene are then mixed with a precursor of the free radical initiator, whereafter the precursor is decomposed to obtain the free radical initiator. The decomposition may, for example, be effected by carrying out the reaction at elevated temperature, eg at a temperature in the range 25°C to 110 C, or photochemically, eg by means of UV radiation. The precursor may be an azo bis valeronitrile, such as 1,2-azo bis isovaleronitrile which has a 10 hour halflife at 67°C, and which is also known by the designation VAZ067.

The reaction temperature may be from 100°C to 300°C, typically from 150°C to 200°C.

The reaction pressure may be at least 20 bar (150psi or 2000kPa), preferably between 50 bar (750psi or 5000kPa) and 100 bar (1500psi or 10000kPa), typically about 85 bar (1232psi or 8500kPa).

The hydroformylation reaction stage may be provided by a reactor capable of handling a homogenously catalysed chemical transformation, such as a continuous stirred tank reactor ('CSTR'), bubble column, or the like.

The olefinic feedstock may, in particular, be a C2 to C20 Fischer-Tropsch derived olefin stream. Thus, the olefinic feedstock may be that obtained by subjecting a synthesis gas comprising carbon monoxide and hydrogen to Fischer-Tropsch reaction conditions in the presence of an iron-based, a cobalt-based or an iron/cobalt-based Fischer-Tropsch catalyst, with the resultant olefinic product then constituting the olefinic feedstock of the process of the invention, or a component thereof constituting the olefinic feedstock of the process of the invention.

In other words, the olefinic product from the Fischer-Tropsch reaction can, if necessary, be worked up to remove unwanted components therefrom and/or to separate a particular olefinic component therefrom, with said particular olefinic component then constituting the olefinic feedstock of the process of the invention.

According to a second aspect of the invention, there is provided a hydroformylation catalyst which includes, as a first component, a metal M, where M is cobalt, rhodium, ruthenium, or palladium ; as a second component, carbon monoxide; as a third component, hydrogen; and, as a fourth component, at least one bicyclic tertiary phosphine having two

cyclic structures and a ligating phosphorus atom, with the ligating phosphorus atom forming part of the largest ring structure of the molecule and with fewer than two hydrocarbon substituents being present on the carbon atoms of the cyclic structures of the molecule, with the components being in the form of a mixture.

The metal M and the bicyclic tertiary phosphine may be as hereinbefore described with respect to the first aspect of the invention.

The invention will now be described by way of example, with reference to the following drawing which shows a simplified flow diagram of a process according to the invention for producing oxygenated products from an olefinic feedstock.

In the drawing, reference numeral 10 generally indicates a process according to the invention for producing oxygenated products from an olefinic feedstock.

The process 10 includes a hydroformylation stage 12, with an olefinic feedstock flow line 14 as well as a synthesis gas feed line 16 leading into the stage 12. A product withdrawal line 18 leads from the hydroformylation stage 12.

The process 10 includes a separation stage 20 into which the line 18 leads, with a product withdrawal line 22 leading from the stage 20. An unreacted feedstock recycle line 24, for recycling unreacted feedstock which is separated from the product produced, leads from the stage 20 back to the stage 12. A catalyst recycle line 26 also leads from the stage 20 back to the stage 12, for recycling catalyst which is separated from the product in the stage 20, back to the stage 12.

In use, a Fischer-Tropsch derived olefinic feedstock is fed into the stage 12 along the flow line 14, as is a synthesis gas comprising a mixture of carbon monoxide and hydrogen, which enters the stage 12 along the flow line 16. In the stage 12, the olefinic feedstock reacts with the carbon monoxide and hydrogen in the presence of a catalyst comprising an intimate mixture or combination of cobalt, carbon monoxide, hydrogen and a bicyclic tertiary phosphine, ie VCH-C12, as hereinbefore described.

The temperature in the hydroformylation stage 12 is typically around 170-190°C, while the pressure is typically around 85 bar (1232psi or 8500kPa). Oxygenated products, consisting mainly of alcohols, are produced, and are withdrawn along the line 18 for further work-up.

The hydroformylation reaction stage 12 typically comprises a hydroformylation reactor system incorporating catalyst recovery and/or catalyst recycle.

In Examples 1 to 5 hereinafter given, all reactions were carried out in a stainless steel stirred autoclave operated at 1000 rpm at the desired constant pressure with syngas delivered on demand. For each run the olefin, paraffinic solvent, and required amount of catalyst stock solution were loaded into the autoclave under argon, the reactor closed and purged with syngas, ie synthesis gas comprising a mixture of carbon monoxide and hydrogen, and then heated to the desired reaction temperature at atmospheric or ambient pressure. The reactions were initiated by pressurising with syngas to the desired reaction pressure.

The syngas employed was a commercially available 2: 1 mixture of hydrogen and carbon monoxide. Catalyst stock solutions were prepared using cobalt (2) octanoate and the appropriate ligand (VCH-C12) in the required ratios. The olefins employed were 1-dodecene, a Fischer- Tropsch derived C13/14 olefin feedstock and a Fischer-Tropsch derived C5 olefin feedstock.

EXAMPLE 1: Comparative example Hydroformylation of 1-dodecene was carried out in the manner described above using a 300 ml stainless steel autoclave. Using standard conditions of 85 bar (8500kPa) of 2: 1 H2 : CO syngas, 170 °C reaction temperature, 1000 ppm Co and a 2: 1 ligand to metal molar ratio, hydroformylations were carried out to determine the selectivity to form linear alcohol products. Selectivities were based on GC analysis of samples taken at 2 hours, ie 2 hours after commencement of the hydroformylation reaction. Linearity refers to the amount of linear alcohol product formed expressed as a percentage of total alcohol product formed. The term"n: iso" refers to the ratio of the linear alcohol product to the 2-methyl branched alcohol product produced. Results are summarised in Table 1. TABLE 1: Comparative catalyst selectivity in hydroformylation of 1- dodecene Ligand VCH-C12 EP Conversion after 2 hours 38% 74% Product composition mass % mass % C12 paraffins 6. 1 % 6. 1 % C12 olefins 58.1% 25.5% C13 aldehydes n-aldehyde 6. 9% 5. 7% 2-methylaldehyde 0. 7 % 0.8% other branched aldehydes 0. 7% 2.7% C13 alcohols n-alcohol 19. 8% 46. 1 % 2-methylalcohol 1.4% 4. 5% other branched alcohols 0.5% 5.6% Heavy by-products 5.8% 3% N: iso 14. 1 10. 2 Alcohol linearity 91 % 82% EXAMPLE 2: Hydroformylation of a Fischer-Tropsch-derived C, 3, 14 olefin feed (comprising 50% C, 3 and C, 4 olefins) was carried out in the manner described above using VCH-C12 as ligand, with reaction conditions of 170°C, 85 bar 8500kPa) of 2: 1 H2: CO syngas, 1000 ppm Co and 2: 1 ligand to metal molar ratio. As can be seen from Table 2, the selectivities observed for this reaction compare very well to those obtained with pure feedstock.

TABLE 2: Comparison of feedstocks using VCH-C12 as ligand Ligand Ci3/C-) 4 Dodecene Conversion after 2 hours 30% 38% Product composition mass % mass % C13 n-aldehyde 22.9% C12 n-alcohol 65.9% C13 i-alcohol 4.7% Ci3 other branched alcohols 6.5% and aldehydes C13 alcohol n: iso 14.0 C14 n-aldehyde 11. 5% C14 n-alcohol 26.3% C, 4 i-alcohol 2.2% C15 n-aldehyde 7.4% C, s n-alcohol 18. 1 % C, 5 i-alcohol 1. 7% Ci4 and Ci5 other branched 32.8% alcohols and aldehydes C1 a alcohol n: iso 12 Cis alcohol n: iso 10.6 EXAMPLE 3: Comparative example A Fischer-Tropsch derived olefin feed which contains 70% 1-pentene was hydroformylated in the manner described above. Using standard conditions of 75 bar (7500kPa) of 2: 1 H2: CO syngas, 1500 ppm Co, 170°C reaction temperature and a 2: 1 ligand to metal molar ratio, hydroformylations were carried out in a 100 ml autoclave to determine the product selectivity to form branched products other than 2-methyl branched alcohols. The alcohol linearity, n: iso ratio and the respective 2-

methyl and 2-ethyl-butanol % by mass are summarised in Table 3 and were determined by GC analysis of samples taken at 2 hours.

TABLE 3: Comparative ligand selectivity in hydroformylation of a Fischer- Tropsch derived Cs olefin feedstock. Ligand Alcohol Alcohol n: i ratio 2-ethyl-butanol linearity EP 81. 7 13. 3 7. 2 VCH-C12 86. 6 13. 4 6. 4

The composition of the feed material and product compositions are summarised in Table 4 and were determined by GC. TABLE 4: Comparative catalyst selectivity in hydroformylation of Fischer-Tropsch derived C5 olefin feedstock. Content of Fischer Product composition Tropsch derived C5 olefin feedstock VCH-C12 EP (mass%) (mass%) (mass%) Conversion after 2 hours 93 95 Butene isomers 0.21 0.45 1-pentene 70 3.43 1.63 C5 paraffins 9.9 16.1 16.7 Pentene isomers 4.8 5.5 1.5 Hexenes 0.4 0. 14 0. 13 Aldehydes 17. 45 11. 12 n-alcohol (hexanol) 40.52 49.35 Iso-hexanol 3.02 3.71 2-ethyl-butanol 1.82 4.36 4-methyl-pentanol 0.47 0.64 3-methyl-pentanol 0.92 2.31 Branched C5 olefins 13.6 Cyclopentadiene 0. 2 C4 olefins and C4 alkanes 0.45 Heavies (include Ligand) 10.31 8.90 N: iso 13. 4 13. 2 Alcohol linearity 86.6 81.7

EXAMPLE 4: Comparative example Hydroformylation of 1-dodecene was carried out in the manner described above using a 50 ml stainless steel autoclave. Mixtures of catalyst stock solutions were prepared using cobalt (2) octanoate and the appropriate

VCH derivative in the required ratios in a decane solvent, and charged to the stainless steel autoclave. The reactor was flushed with syngas and charged to 58 bar (5800kPa) with 2: 1 H2: CO gas mixture. The autoclave reactor was heated to 160°C, with an accompanying pressure rise to ca. 75 bar (7500kPa) (equilibration at temp/pressure for ca. 30 min), and the reaction initiated by injecting 1-dodecene feed with 2: 1 H2 : CO syngas pressurization to 85 bar (8500kPa). Using standard conditions of 85 bar (8500kPa) of 2: 1 H2: CO syngas, 170 °C reaction temperature, 1000 ppm Co and a 2: 1 ligand to metal molar ratio, hydroformylations were carried out to determine the selectivity to form linear alcohol products employing different VCH derivatives with different alkyl or aryl substituents on the phosphorus atom. Selectivities were based on GC analysis of samples taken at full conversion of the olefin feed in the hydroformylation reaction. Linearity refers to the amount of linear alcohol product formed expressed as a percentage of total alcohol product formed. The term"n: iso" refers to the ratio of the linear alcohol product to the 2-methyl branched alcohol product produced. Results are summarised in Table 5. TABLE 5: Comparative ligand selectivity in hydroformylation of a dodecene olefin feedstock. Ligand Alcohol linearity Alcohol n: i ratio EP 75. 5 8. 0 VCH-Ph 76. 9 8. 1 VCH-Cy 80. 3 10. 9 VCH-1-Me-C7 79. 0 10. 2 VCH-C 10 83. 4 12. 6 Legend : VCH-pH refers to a VCH derivative containing a phenyl substituent, ie Ri is phenyl VCH-Cy refers to a VCH derivative containing a cyclohexyl substituent, ie Ri is cyclohexyl VCH-1-Me-C7 refers to a VCH derivative containing a branched alkyl substituent, ie 1-methylheptyl with the numbering starting on the carbon bonded directly to the phosphorus atom, ie Ri is 1-methylheptyl.

VCH-C10 refers to a VCH derivative containing a decyl derivative, ie Ri is decyl EXAMPLE 5: Comparative example Hydroformylation of 1-dodecene was carried out in the manner described above using a 300 ml stainless steel autoclave. Standard conditions of 85 bar (8500kPa) of 2: 1 H2 : CO syngas, 170 °C reaction temperature, 1000 ppm Co and a 2: 1 ligand to metal molar ratio of the appropriate VCH were used. Hydroformylations were carried out to determine the selectivity to form dodecane and were based on GC analysis of samples taken at full conversion of the olefin feed. Results are summarised in Table 6.

TABLE 6: Improvements in reaction rate and paraffin make compared to VCH-C12. Ligand Reduction in Increase in reaction rate (%) hydrogenation (%) VCH-C10 10 NA VCH-Ph 31 30 VCH-2,4, 4- 24 40 trimethylpentyl VCH-Ethyl vinyl 33 NA ether EXAMPLE 6 Synthesis of 2-dodecyl-2-phosphabicyclo [3. 3. 1] nonane, ie a [3. 3. 1] phosphabicvclononane of formula (V) A stirred inerted reacted was charged with 442g (2.19 moles) of dodecylphosphine. A solution containing 35g (0.182 moles) of 1,2-azo bis isovaleronitrile (VAZ068) in 235g (2.17 moles) of 4-vinylcyclohexene and 133g of toluene was added to the dodecylphosphine, and the resultant reaction mixture maintained under stirring, for a 24 hour period, at 70°C. The ratio of desired product: unconverted dodecylphosphine : intermediate: by-product, in the resultant mixture, was 56.0 : 2.5 : 3.8 : 9.9.

This product mixture was then heated under 2mm Hg (0. 27kPa) pressure at 200°C to remove the unconverted dodecylphosphine and their volatile impurities. The recovered product contained 85% 2-dodecyl-2- phosphabicyclo [3. 3. 1] nonane.

EXAMPLE 7 Synthesis of 2-cyclohexyl-2-phosphabicyclo [3. 3. 1] nonane A stirred inerted reactor was charged with 17 g (0. 15 moles) of cyclohexylphosphine. A solution containing 3.5 g (0.018 moles) of 1,2 - azo bis isovaleronitrile (VAZ068) in 17.3 g (0.16 moles) of 4-

vinylcyclohexene and 133 g of toluene was added to the cyclohexylphosphine, and the resultant reaction mixture maintained under stirring, for a 78 hour period, at 90°C. The ratio of desired product: unconverted cyclohexylphosphine : intermediate: by-product, in the resultant mixture, was 83: 0: 3.8 : 13.2. This product mixture was then heated under 2mm Hg (0.27kPa) pressure at 200 C to remove the unconverted cyclohexylphosphine and other volatile impurities. The recovered product afforded a 55% yield of 2-cyclohexyl-2- phosphabicyclo [3. 3. 1] nonane.

EXAMPLE 8 Synthesis of 2-phenyl-2-phosphabicyclo [3. 3. 1] nonane A stirred inerted reactor was charged with 9.5 g (0.086 moles) of phenylphosphine. A saturated solution of 1, 1-azo bis cyclohexanecarbonitrile (VAZO) in toluene (10 ml) containing in 9.3 g (0.086 moles) of 4-vinylcyclohexene was added to the phenylphosphine, and the resultant reaction mixture maintained under stirring, for a 78 hour period, at 88°C. 31P NMR indicated 83% of the desired tertiary phosphine product with 4 % of the secondary phosphine remaining. This product mixture was then heated under 2mm Hg (0.27kPa) pressure at 200 C to remove the unconverted phenylphosphine and other volatile impurities. The recovered product product afforded a 36% yield of 2- phenyl-2-phosphabicyclo [3. 3. 1 nonane.

Thus, it has surprisingly been found that the selectivity to linear alcohol products and/or the selectivity to a combination of linear and 2-methyl branched alcohol is enhanced if a novel catalyst according to the invention and consisting of a complex mixture of cobalt, carbon monoxide, hydrogen and a bicyclic tertiary phosphine having two cyclic structures and a ligating phosphorous atom, where the ligating phosphorus atom is neither in a bridgehead position nor a member of a bridge linkage, and with fewer than two hydrocarbon substituents being

present on the carbon atoms of the cyclic structures of the bicyclic tertiary phosphine, is used as a hydroformylation catalyst, with either pure olefinic feedstocks or with olefinic feedstocks derived from Fischer- Tropsch processes.