This invention relates to a method for separating water soluble Group VIII noble metal- ligand complex catalysts from the crude reaction product of a noble metal-catalyzed hydroformylation reaction by contacting the crude reaction product to a hydrophobic membrane whereby the water soluble Group VIII noble metal-ligand complex catalysts are retained by the membrane _s reten -tte. and the unreacted olefm feed and the hydroformylation reaction product are uassed throush the membrane as Dermeate.

BACKGROUND OF THE INVENTION

Hydroformylation reactions involve the preparation of oxygenated organic compounds by the reaction of carbon monoxide and hydrogen (synthesis gas) with carbon compounds containing olefinic un∞turation. The reaction is typically performed in the presence of a carbonyiation catalyst and results in the formation of compounds, for example, aldehydes, which have one or more carbon atoms in their molecular structure than the starting olefinic feedstock.

By way of example, higher alcohols may be produced in the so-called oxo process by hydroformylation of commercial C- -Ci2 olefin fractions to an aldehyde-containing oxonation product, which on hydrogenation yields the corresponding C7-C13 saturated alcohols. The oxo process is the commercial application of the hydroformylation reaction for making higher aldehydes and alcohols from olefms. The crude product of the hydroformylation reaction will contain catalyst, aldehydes, alcohols, unreacted olefm feed, synthesis gas and by-products.

A variety of transition metals catalyze the hydroformylation reaction, but only cobalt and rhodium carbonyl complexes are used in commercial oxo plants. The reaction is highly

e.xouierπuc: the heat release is ca. 125 J/mol (30 kcai/moi). The posiuon of the formyl group in the aidehyαe product depends upon the olefin type, the catalyst, the solvent, and the reaction conoiuons. Reacuon conditions have some effect and. with an unmodified cobalt catalyst, the yield of straight chain product from a linear olefin is favored by higher CO partial pressure. In the hydroformylauon of terminal olefmic hydrocarbons, the use of a catalyst containing selected compiexing hgands. e.g.. tertiary pnosphines. results in the predommant formauon of the normal isomer.

In commercial operauon. the aldehyde product usually used as an intermediate which is converted by hydrogenauon to an alcohol or by aldolizauon and hydrogenauon to a higher aicohol. The aldol-hyαrogenauon route is used primarily for the manufacture of 2-eιhylhexanoi from propyiene via π-butyraidehyαe.

The hydroformylauon reacuon is catalyzed homogeneously by carbonyls of Group vm metals but there are significant differences in their relative activities. Roelen. using a cobalt catalyst, discovered hydroformylauon in 1938. Dicobalt octacarbonyl. Cθ2(CO g, which either is introduced directly or formed in situ, is the primary convenuonal oxo catalyst precursor. Using an unmodified cobalt catalyst, the rauo of linear to branched aldehyde is relatively low.

Much oxo research in the past 25 years has been directed to improving reaction selectivity to the linear product. Introducuon of an organophosphine ligand to form a complex, e.g., Cθ2>CO)6[P(π-C4H9J3]2, significantly improves the selecuvity to the straight-chain aicohol.

Recent developments of low pressure rhodium catalyst systems have been the subject of a considerable body of patent an and literature, and rhodium-triphenyl phosphine systems have been widely, and successfully, used commercially for the hydroformylation of propyiene feedstocks to Droducε butyraldehyde.

The first commercial oxo process to erapioy a rhodium-modified catalyst was developed by Union Carbide. Davy Powergas. and Johnson Matthey. In this application, the compiexed rhodium catalyst is dissolved in excess ligand and the reacuon is run at relatively low pressures and temperatures as compared to a conventional oxo process. The ratio of normal to iso isomers is high relaύve to conventional oxo processes and so is favored as a process for the production of N-butyraldehyde.

A recent process commercialization has been that of Rhone-Pouienc and Ruhrchemie which produces butyraidehyde from propyiene but the ligand is a sulfonated triphenylphosphine and is utilized as a water soluble sodium salt. Turnover rates are less than in the all-organic system, but the normal to iso raiios are high and the catalyst may be separated easily from the reaction product by separauon of the aqueous layer containing the catalyst and the organic iayer which constitutes the product.

In the formation of linear aldehydes using a ligand-modified rhodium-catalyzed homogenous process, the reactor comprises the rhodium complex catalyst, excess triphenylphosphine and a mixture of product aldehydes and condensation by-products. The product aldehyde may be recovered from the mixture by volatilization directly from the reactor or by distillation in a subsequent step. The catalyst either remains in or is recycled to the reactor. However, the complex catalyst and triphenylphosphine ligand are slowly deactivated and eventually the spent catalyst is removed for recovery of rhodium and reconversion to the active catalyst. This process, although effective for lower molecular weight aldehyde production, is not favored for higher molecular weight aldehydes which are higher boiling, distillation temperatures needed for aldehyde recovery are higher and catalyst deactivation is accelerated.

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The aqueous iigand system is aiso very effecuve for propyiene but rugner molecular weight olefm feeds are not sufficiently soluble in the aqueous cataiyst medium to allow acceptable rates of aldehyde formauon. Thus, althougn separauon of the higher molecular weight aldehyde should be more facile than the all-organic system, the slow rates preclude commercial acceptability.

In some cases, such as where the products of the reacuon are relauvely high boiling or where the olef feed is not sufficiently soluble in water to permit satisfactory reacuon rates, neither the process where the products are removed from the catalyst by distillauon or stripping nor where the products are decanted from an aqueous catalyst soluuon may be utilized successfully. In such cases, u may oe advantageous to utilize an aqueous medium to contam the catalyst and add a surfactant to enhance phase contacting so as to improve rate and selecuviiy to the desired products. This type of process is called "Phase Transfer Catalysis." However, when the surfactant is added, some carry-over of the noble metal into the organic phase at the conclusion of the process often results.

The present inventors have discovered that when they satisfactorily hydroformylated olefins in the presence of water soluble Group m noble metal-ligand complex catalysts using an aqueous-organic medium enhanced by surfactants, the catalyst can be recovered quanutauvely from a crude reacuon product which includes both an aqueous phase and an orgamc phase by employing membrane separauon either internal or external to the hydroformylauon reactor.

It has been known to use membranes to separate catalysts from an aqueous solution. .An example is set forth m European Patent No. 0 263 953 , published on August 29. 1986 (assigned to Ruhrchemie which discloses a process for separating rhodium complex compounds, which contam water-soluble orgamc phosphmes as ligands. from aqueous solutions

_ which excess phosphine ligand and. if necessary, other components are aiso dissolved, is characterized by die fact that the aqueous solution is subjected to a membrane separation process. According to this process, volatile organic substances are separated from the solution prior to conducting die membrane separauon process. A typical membrane for use in this process is a cellulose acetate membrane. This process only involves the separation of water- soluble ligands and noble metal catalyst from an aqueous solution. .As such, this separation process does not pertain to the separation of a water soluble noble metal cataiyst and a water soluble ligand from an organic-aqueous emulsion, dispersion or suspension produced from the hydroformylation process.

.Another patent which utilizes cellulose acetate, silicone rubber, poiyolefm or polyamide membranes in the separation of catalysts from high boiling by-products of the hydroformylation reaction is Great Britain Patent No. 1312076. granted on May 15. 1970. According to this patent die aldehydes produced during the hydroformylation process are continuously withdrawn as an overhead vapor stream. The liquid stream containing the heavy by-products with the cataiyst is passed over a membrane wherein approximately 78-94.3% of the catalyst is retained and the heavy by-products permeated. This is an unacceptably low level of catalyst retention which is overcome by the process of the present invention.

In like manner. Great Britain Patent No. 1432561. granted on March 27. 1972, (assigned to

Imperial Chemical Industries LTD.) discloses a process for the hydroformylation of olefins which comprises reacting an olefin at elevated temperature and pressure with CO and H2 in the presence of a compound of a group VIE metal and a biphyllic ligand of a trivalent P. As or Sb to give a crude liquid hydroformylation product containing an aldehyde and or an alcohol, separating die aldehyde and/or alcohol from the crude product and leaving a liquid, bringing the liquid after separation of the Group VIII metal compound and free from aldehyde and alcohol under reverse osmosis conditions into contact with one side of a silicone rubber semi-permeable

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memDrane in which the poiymer chains have been at least partly cross-linked by gamma radiauon whereby the liquid retained by the membrane contains a higher concentration of Group VTH metal compounds and/or biphyllic ligand than the original liquid.

In die article by Gosser et al.. eπuded "Reverse Osmosis in Homogeneous Catalysis." Journal of Molecular Catalysis. Vol. 2 (1977), pp. 253-263. a selecuvely permeable polyimide membrane was used to separate soluble transition metal complexes from reacuon mixtures by reverse osmosis. For example, separauon of cobalt and rhodium complexes from hydroformylauon products of 1-pentene. That is, a soluuon of 0.50 g of R H(CO (PPh3J3 ^m ^ ml of benzene and 10 ml of 1-pentene was stirred at 50° C wuh a CO/H2 mixture at ca. 4 atm pressure until no further pressure drop occurred. The pentene was completely converted to aldehydes according to proton nmr analysis. The soluuon was permeated through a polyimide membrane under 68 atm mtrogen pressure. The permeate (4.5 g passed in 2 mm.) showed only 9% of the original rhodium concentrauon by X-ray fluorescence.

The permeauon rate of rhodium as set forth above, i.e., 9%, is considered unacceptable. The rhodium cataiyst should be retained in an amount of greater than 99.5% to be a commercially feasible process.

Another example of the use of membranes to separate metal catalysts from hydroformylation products is set forth in Dutch Patent No. 8700881, published on November 1, 1988. The method disclosed therein relates to one which improves d e efficiency of membrane separauon of hydroformylauon products from expensive organometallic catalyst containing reacuon mixtures. In Dutch Patent No. 87/881 a polydimemylsiloxane membrane havmg a thickness of 7 microns applied to a Teflon® support was used in me separauon of a reaction mixture containing C9-C15 alcohols, a homogeneous catalyst system comprising an organometallic complex of a transiuon metal from Group VIII or Vila or Va of the Periodic

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Table, e.g., a tπcarbonyl(triphenylphosphine) cobalt catalyst, and 40% low- viscosity lubricating oil (an anusweliing or de-swelling agent). At a flow of 133 kg nv-day, the cobalt contents in the feed, retentate. and permeate were 600, 910, and 18 ppm. verses 840, 1930, and 160 ppm, respecuvely, for a mixture widiout the de-swelling agent. This process is directed to the separation of product from a reacuon mixture containing a homogeneous catalyst system by means of a membrane, whereas the present invention is directed to a heterogeneous catalyst system comprising bom an organic and an aqueous layer. The ligands disclosed in Dutch Patent No. 8700881 are all organic soluble ligands, e.g., triphenylphosphine. tri-n-alkylphosphine or acetyl acetonate. whereas diose used in the present invention are water soluble ligands. Critical to die process of Dutch Patent No. 8700881 is die addition of a de-swelling agent to die reaction mixmre which assists in the separation of die products from me reaction mixture.

Each of die aforementioned processes for removing metal catalysts from crude hydroformylation reaction products are bodi costly in terms of unrecovered catalyst and. as such, would require further expensive treatment of the streams to recover catalyst

The present invention provides a ligand and membrane combination which allows for d e retenuon of over 99.5% of the noble metal catalyst from die hydroformylation reaction product which is passed over die membrane. Moreover, the hydrophobic membrane used in accordance with the process of the present invention remains thermally and hydroiyϋcally stable during separauon.

The present inventors have been able to demonstrate that an aqueous-organic-catalyst mixture can be separated from me crude hydroformylation product mixture using a hydrophobic membrane and a perstracting organic solvent. This novel process permits the organic products to permeate through die membrane, while retaining the rhodium cataiyst and all other water soluble components.

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The present invenuon also provides many addiuonai advantages wtuch shall become apparent as described below.

SUMMARY OF THE INVENTION

The present invenuon relates primarily to a process wherein an aqueous emulsion, suspension or dispersion of a crude reacuon product comprising a water soluble Group VTH noble metal-ligand complex catalyst, unreacted olefm feed and a hydroformylauon reaction product is contacted with or passed over a hydrophobic membrane capable of retaining the water soluble rhodium-ligand complex catalyst as retentate and permitting die unreacted olefm feed and orgamc hydroformylauon reacuon product compnsmg higher aldehydes and higher alcohols to permeate dieredxrough. Opuonally. the aqueous emulsion, suspension or dispersion is first settled before delivering the orgamc phase, i.e., d e hydroformylation reacuon product with smaller amounts of the water soluble Group VH1 noble metal-ligand complex catalyst, to die membrane for separation. It is also opύonai to add a surfactant to the noble metal-catalyzed hydroformylation reacuon. Typical olefins used in die aforementioned hydroformylauon process are C4 to C20, preferably C$ to Cι _D .

The following is a preferred method for separating a water soluble noble metai catalyst from the crude reacuon product of a noble metal-catalyzed hydroformylauon reacuon run m aqueous soluuon. in an aqueous emulsion or as an aqueous suspension. The crude reacuon product includes an aqueous phase containing a water soluble Group VTA noble metal-ligand complex catalyst, and an orgamc phase containing unreacted olefm feed and an orgamc hydroformylation reacuon product The method compri∞s me following steps: (a) contacting die crude reacuon product widi a hydrophobic membrane capable of allowing a substanual portion of die unreacted olefm feed and me organic hydroformylation reaction product to pass ineredirough while retaining a substanual poraon of the water soluble Group VIII noole metai-

iigand complex catalyst: (b) removing unreacted olefm feed and orgamc hydroformylation reacuon product which pass through the hydrophobic membrane as permeate; and (c retaining die water soluble Group VEtt noble metal-ligand complex catalyst as retentate in an amount of about 99.5% or greater.

The noble metal-catalyzed hydroformylation reaction preferably includes the steps of: reacting an olefin with hydrogen and carbon monoxide in the presence of a water soluble Group vm noble metal-ligand complex catalyst, at a temperature in die range between about 80 to 125° C to produce an aldehyde having a normal aldehyde to isomeric aldehyde raύo in the range of between about 0.5: 1 to about 80: 1.

The ligand is preferably at least one compound selected from die group consisting of: Na-p- Na-m-(diphenyiphosphino)benzenesulfonate. and tπ-( sodium m- suifophenyD-phosphine.

The surfactant is preferably at least one compound selected from d e group consisting of cetyltrimemylammonium bromide, sodium laurate, sodium stearate, and linear dodecylbenzene sulfonate.

The hydrophobic membrane is preferably one membrane selected from d e group consisting of: a high density polyethylene crosslinked membrane, a natural latex rubber membrane, a polyvinylidene difluoride membrane, a poiychlorotrifluoroediylene membrane, and a polytetrafluoroediyiene membrane.

A further object of the present invention is a metiiod for producing higher aldehydes and higher alcohols which comprises: (a) hydroformylating an olefinic feedstock with syntiiesis gas in die presence of a water soluble Group Vffl noble metal-ligand complex cataiyst to form a

cruαe reacuon product compnsed or an orgamc phase containing nigher aldehydes, higher alcohols and secondary products ano an aqueous phase containing a water soluble Group VHI noble metal-ligand complex catalyst: (b) removing the water soluble noble metal catalyst from die crude reacuon product by feedmg die crude reacuon product to a membrane separator which comprises a hydrophobic membrane capable of allowing a substanuai poruon of the hydroformylauon product. ι.e.. higher aldehydes, higher alcohols and secondary products, and unreacted olef feed to pass therethrough while retaining a substanual poruon of die water soluble Group VHI noble metal-ligand complex catalyst: (c) recovering the higher aldehydes, higher alcohols and secondary products as permeate: (d) retaining the water soluble Group VHI noble metal-ligand comDlex catalyst as retentate: and (e) recycling die retained water soluble Group VIII noble metal-ligand complex catalyst to die hydroformylauon step (.a).

Opuonaily, die aforemenuoned method mcludes the additional step wherein the crude reacuon product is separated into an aqueous layer and an orgamc layer before it is fed to d e membrane separator. The orgamc layer ώereafter being fed to the membrane separator and the aqueous layer and retentate from the membrane separator are recycled to the hydroformylation reactor.

The noble metai-cat-aiyzed hydroformylauon reaction typically mvolves die reacting of a linear alpha olefm with carbon monoxide, and hydrogen in the presence of a water soluble Group vm noble metal-ligand complex catalyst, at a temperature m me range between about 80 to 125° C. and a pressure of 1 to 100 atmospheres to produce an aldehyde havmg a normal to iso rauo in the range of between about 0.5:1 to about 80:1.

Other and further objects, advantages and features of the present mvenuon will be understood by reference to die following spe ficauon in conjuncuon with die annexed drawings, wnerein like parts have been given like numbers.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic representation of a membrane separator according to d e present invention wherein a hydrophobic membrane retains a water soluble Group VU3 noble metal- ligand complex catalyst, and permits me passage dierethrough of organic hydroformylation reaction product and unreacted olefm feed:

Fig. 2 is a schematic representation of a membrane reactor system according to the present invention which is used to separate water soluble Group VTQ noble metal-ligand complex catalysts from organic hydroformylation reaction products and unreacted olefin feed: and

Fig. 3 is schematic representation of another embodiment of the membrane reactor system according to the present invention which includes a settling tank used to settle the aqueous and organic phases of the crude reaction product before delivering the organic phase to d e membrane separator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hydroformylation is a process of converting oiefins to a product of one or more additional carbon numbers by d e addition of carbon monoxide and hydrogen to the double bond(s) of the olef in die presence of a catalyst at elevated temperatures and pressures. A typical hydroformylation process is demonstrated below:

Rh + Ligud

RCH=CH ₂ + CO + H ₂ > RCH2CH2CHO + RCHCH3CHO

HEAT Nona- Of) IM (T)

At a temperature of 100° C and a pressure of 150 lbs. the normal to iso ratio using rhodium as die catalyst may be below 1 or even as high as 100. depending on die ligand, ratio of ligand to

rhodium, etc. When cobalt is used as die catalyst ano is not modified by a ϋgand. die normal to iso rauo is below 3 at most.

.Another metiiod for catalyuc hydroformylauon of olefins, us g a convenuonal approach is set forth in U.S. Patent No. 4.399.312 (Russell et al.), which issued on August 16. 1983. The hydroformylauon metiiod discussed in the above-menuoned patent involves die reacting together, at elevated temperature and pressure, of an olefin. H2 and CO in the presence of a catalyst compnsmg a water soluble complex of a noble metal and an amphiphilic reactant a reaction medium comprising an aqueous phase and an orgamc phase. The organic phase includes a highly reacuve olefin. e.g., C3-C2Q, and a solvent. The noble metal cataiyst is typically PL Rh. Ru or Pd. The aqueous phase preferably contains a water-soluble phosphine in complex combinauon with a complex or catalyuc precursor of die noble metai. e.g., sulfonated or carboxylaied tnaryl phosphines. The amphiphilic reagent is typically an amomc. nonionic or caiionic surfactant or phase transfer agent such as a complex ammonium salt or a polyoxyediylene nonionic surfactant The preferred ratio of aqueous phase to organic phase is 0.33: 1 to 5: 1. die ratio of H2 to CO is 1:1 to 5: 1. die content of precious metal in the aqueous phase is 100-500 ppm and d e rauo of amphiphilic reagent to precious metai is up to 100: 1 on a molar basis. It is preferable tiiat the reacuon be earned out at 300-10.000 kPa. especially 300- 3.000 kPa and at a temperature m the range between about 40-150° C.

The present mvenuon can best be described by referring to d e attached drawings, wherein figure 1 is a schemauc representation of a membrane separator I comprising a hydrophobic membrane 3. Membrane separator 1 is preferably used to separate a water soluble Group VHI noble metal-ligand complex cataiyst from a crude reaction product of a noble metal-catalyzed hydroformylation reacuon run in aqueous solution, in an aqueous emulsion or as an aqueous suspension. The crude reacuon product typically includes an aqueous phase containing a water soluble Group vm noble metal-ligand complex catalyst and an orgamc phase containing

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.nreacted oiefin feed and an orgamc hydroformylation reacuon product. Separauon occurs by contacting the crude reaction product witii hydrophobic membrane 3 which is capable of allowing a substantial poruon of d e unreacted olefm feed and organic hydroformylation reaction product to pass therethrough while retaining a substantial portion of the water soluble Group VTA noble metal-ligand complex catalyst. The unreacted olefm feed and organic hydroformylation reaction product which pass through hydrophobic membrane 3 as permeate is then removed from membrane separator 1 for further downstream treatment. The retentate which comprises water soluble Group VTH noble metal-ligand complex catalyst and some of die orgamc phase constituents is recycled to the hydroformylation reactor.

The organic hydroformylation reacuon product and unreacted olefm feed are permeated, eitiier by perstraction or pervaporauon. tiirough hydrophobic membrane 3 which retains the water-soluble catalyst quantitatively.

The preferred water soluble ligand is one compound selected from die group consisting of: Na-p-(diphenylphosphino)benzoate. Na-m-(diphenylphosphino)benzenesulfonate. and tris- ( sodium m-sulfophenyl)-phosphine. .And die preferred water soluble noble metal catalyst is rhodium. The nobie metal-catalyzed hydroformylation reaction according to die present invenuon preferably mvoives the reacting of an olefm with hydrogen and carbon monoxide ( syntiiesis gas) in the presence of a water soluble Group vm noble metal-ligand complex catalyst, at a temperature in the range between about 80 to 125° C to produce an aldehyde havmg a normal to iso ratio in die range of between about 0.5:1 to about 80:1. Optionally, a surfactant may be added to d e noble metal-catalyzed hydroformylation reaction. The surfactant is preferably one compound selected from me group consisting of cetyltrimethylammonium bromide, sodium laurate. sodium stearate. and linear dodecvlbenzene sulfonate.

Hydroonobic memDrane 3 is preierably selected from die group consisting of: a high density polyethylene crosslinked memorane. a natural latex rubber memDrane. a poiyv ylidene difluoπde membrane, a polychlorotnfluoroethyiene memorane. and a poiyietrafluoroethyiene memorane.

The me od for producing higner aldehydes and higher alcohols accordmg to the present invenuon can best be descnbed by referπng to fig. 2. wherein an olefm feedstock is hydroformylated with syntiiesis gas in die presence ot a water soluble Group VIE noole metai- ligand complex cataiyst in hydroformylauon reactor loop compnsmg vessel 10. pump 16 and separator 18 to form a crude reacuon product The crude reacuon proαuct is typically comprised of an emulsion of the orgamc phase containing unreacted olefm feed and orgamc hydroformylauon reacuon product and an aqueous phase containing a water soluble Group VEI noble metal-ligand complex catalyst. This emulsion of die orgamc phase and aqueous phase is sent to membrane separator 18 by pumping means 16 for die purpose of removing me water soluble noble metal catalyst from me crude reacuon product Membrane separator 18 includes a hydrophobic membrane 20 which is capable of allowing a substantial poruon of die hydroformylauon reacuon product and unreacted olefm feed to pass from reactant chamber 22 uirougπ memDrane 20 and mto sweep chamber 24. while retaining a substanual poruon of die water soluble Group VIE noDle meul-hgand complex catalyst witiun reactant chamDer 22. The hydroformylauon reacuon product and die unreacted olefin feed which pass d rough membrane 20 are swept away by means of an orgamc sweep solvent which can be supplied via reactor vessel 26 and pumping means 28.

Hydropnobic membrane 20 is substanually impermeable to water soluble Group VIE noble metal-ligand complex catalyst which are retained as retentate m reactant chamber 22 and diereaiter recycled to reacuon vessel 10 via pump means 23 for further reacuon witii die olefinic

feedstock. Pump means 23 is also capable of removmg die permeate from sweep chamber 24 and thereafter sending the permeate for further downstream treatment

.As shown in fig. 3. die crude reaction product can optionally be separated into an aqueous layer and a organic layer before it is fed to membrane separator 18. This separation takes place in a settier or other conventional settling tank 30. wherein organic layer 32 rises to the top and aqueous layer 34 settles to the bottom of settler 30. Aqueous layer 34 is recycled to hydroformylation reactor vessel 10 and organic layer 32 is fed to membrane separator 18. wherem water soluble Group VTH noble metal-ligand complex catalyst are retained as retentate and unreacted olefm feed and organic hydroformylation reaction product pass through hydrophobic membrane 20 as permeate. The retentate is recycled to reactor vessel 10 to be again used in die hydroformylation process.

EXAMPLES l and 2

Using an analytical balance. 0.122 grams (2.74 x 10" ⁴ moles) of rhodium acetate dimer containing 0.0551 grams (5.35 x 10~^g atom) of rhodium was weighed into a 1 dram vial and transferred to die nitrogen dry box for catalyst preparation. Next 1.47 grams (5.34 x 10" ³ moles) of diphenylphosphinobenzoic acid and 70 grams of IN NaHCθ3 were weighed into a

125 mi Erlenmeyer flask and heated to approximately 75° C with magnetic sumng to effect solution of the diphenylphosphinobenzoic acid. The resulting clear and colorless liquid was cooled to room temperature and the rhodium acetate dimer was added. A cloudy orange liquid witii orange solids resulted. Finally, 2.0 grams (5.49 x 10"--* moles) of cetyltrimediyiammonium bromide (Example 1) was added. A cloudy orange emulsion resulted in fine orange solids. In Example 2. 2.0 grams (5.49 x 10'- ⁵ moles) of lauric acid was used in place of die cetyltrimethylammomum bromide.

- 16 - Into a 500 πu Erlenmeyer flask eαuipped witii a maeneuc surπng Dar were weigned 179.0 grams 11.28 moles) of decene-1 and 10.6 grams ι0.047 moiei of hexadecane. The ciear and colorless liquid was deaerated with nitrogen for fifteen minutes with surnng.

The membrane reactor was assembled and the membrane to be tested. 9 cm diameter, sandwiched by two pieces of Gortex® (0.2 micron Teflon®) also 9 cm in diameter, and were mounted in place and die membrane reactor unit was purged witii nitrogen. Next die system was evacuated witii a vacuum. The catalyst soluuon was drawn witii vacuum to the catalyst side of die membrane and then die decene/hexadecane soluuon was added to d e same side. Finally, die nexene hexaoecane/squaiane soluuon was drawn with vacuum into die sweep side of the unit to act as he perstracung solvent The hexadecane was employed as an internal standard.

Both die catalyst soluuon and sweep soluuon were circulated at a rate of about 1.000 cc/minute. The contents of the membrane reactor umt were pressunzed to 100 psi pressure with a 50/50 mixture of hydrogen/carbon monoxide, men heated to about 80° C in tiiirty minutes. At 77° C. me hydrogen carbon monoxide pressure was increased to 150 psi operating pressure and die supply of hydrogen/carbon monoxide kept constant throughout the run.

At the conclusion of the run. die clear and colorless uquio on die sweep side was analyzed for rhodium. The catalyst soluuon on standing separated into two phases, i.e.. clear and colorless upper phase and a yellow-brown lower aqueous phase. The results of the two examples were as follows. Example 1 used a high density polyediylene crosslinked by radiauon 11.05 mils) membrane wherem only 0.086 ppm of rhodium were detected in the permeate, i.e.. 0.02%. In Example 2 a natural latex rubber membrane demonstrated less than 0.011 ppm rhodium in die permeate, i.e.. 0.002%.

EXAMPLE ?

A membrane reactor was assembled witii a 9 cm HJM-AR® (i.e., a chlorotrifluoroetiiyiene and ethylene copolymer) membrane sandwiched between two pieces of Gortex® (0.2 micron Teflon®) also 9 cm in diameter. The HALAR® membrane was mounted in place and die membrane reactor was purged with mtrogen. Next the system was evacuated with a vacuum. The catalyst solution was drawn with vacuum to die catalyst side of the membrane and men a decene hexadecane solution was added to die same side. Finally, the hexene hexadecane squalane solution was drawn with vacuum into die sweep side of die unit

Both the catalyst solution and sweep solution were circulated at a rate of about 1.000 cc minute. The contents of the membrane reactor unit were pressurized to 100 psi pressure with a 50/50 mixture of hydrogen carbon monoxide then heated to about 80°C for tiiiπy minutes. At 77°C, die hydrogen carbon monoxide pressure was increased to 150 psi operating pressure and die supply of hydrogen carbon monoxide kept constant tiiroughout the run.

At d e conclusion of d e run. die clear and colorless liquid on die sweep side was analyzed for rhodium. The catalyst solution on standing separated into two phases, i.e.. a clear and colorless upper phase and a yellow-brown lower aqueous phase. The HALAR® membrane permitted only 0.13 ppm of rhodium to permeate tiieretiirough, i.e.. less than 0.03%.

It is anticipated that halogenated polymers, as a class, will be advantageous in this type of membrane reactor application. It also appears tiiat hydroformylation reaction products which included a water soluble ligand, such as p-diphenyiphosphinobenzoic acid, exhibit satisfactory normal to iso ratios based upon aldehydes, as well as satisfactory turnover number.

While we have shown and described several embodiments in accordance witii our invenuon. it is to be clearly understood that die same are susceptible to numerous changes

apparem to one s_U=- in _= an. _____ « ~ no. w,sh _ be ___- to _= ___ show ^¬ ed described b ___ to show _1 chang s and modificauons which come w hin me scop. _

die appended claims.