CA1338869C - Process for hydroformylation with rhodium catalysts and the separation of rhodium therefrom - Google Patents

Abstract

A process for separating rhodium from mixtures thereof, comprising extracting said rhodium with an aqueous solution of a rhodium complexing agent and a solubilizer. A process for preparing aldehydes in the presence of both the complexing agent and the solubilizer is also set forth. The solubilizer is generally selected from salts of carboxylic acids having 8-20 carbon atoms, alkyl sulfonates, alkyl aryl sulfonates, amines and quaternary ammonium compounds of Formula II

(II) wherein A is alkyl, alkoxy, hydroxyalkyl, aryl having 6-25 carbon atoms, or R7CONHCH2CH2CH2- wherein R7 is alkyl having 5-11 carbon atoms; B is an alkyl having 1-25 carbon atoms, an aryl having 6-25 carbon atoms, or an .omega.-hydroxy alkyl having 1-4 carbon atoms; C and D are each independently an alkyl or .omega.-hydroxy alkyl having 1-4 carbon atoms or form, together with each other and the bridging N, a 5 or 6 membered heterocyclic ring; E is a halide, sulfate, borate, sulfonate, lactate or citrate; and p is the number of charges on E.
The rhodium complexing agent is preferably a triaryl phosphine carboxylate or sulfonate.

Description

13~8869 A PROCESS FOR ~yDRoF~RMyLATIoN WITH RHODIUM
CATALYSTS AND THE SEPARATION OF RHODIUM THEREFROM

The present invention relates to improved methods of recapturing rhodium from various mixtures. It is especially related to the recovery of rhodium from hydroformylation reaction product mixtures.

The preparation of aldehydes and alcohols by the addition of carbon monoxide and hydrogen to an olefinic double bond, hydroormylation, is a well known process. It is catalyzed by metals in Group VIII of the Periodic Table or compounds thereof which are capable of forming carbonyls or hydridocarbonyls under the reaction conditions. Previously, cobalt and cobalt compounds were primarily used as hydroformylation catalysts, but rhodium catalysts are becoming increasingly important.

Rhodium is employed, in these reactions alone or as a complex. The complexes ~inding greater and greater applications are primarily complexes of rhodium with organic phosphines. The uncomplexed rhodium generally catalyzes the Oxo synthesis (hydroformylation reaction) at pressures of 250-300 bar (2.5 x 104 to 3 x 104 kPa). Complexed rhodium permits the reaction to take place at 10-50 bar (1 x 103 to 5 x 103 kPa) Ttle rhodium catalysts are becoming increasingly valuable in hydroformylations because they demonstrate clear advantages over the analogous cobalt catalysts. The rhodium mediated reactions result in greater selectivity (n-aldehydes being preferred over iso aldehydes), greater activity, and fewer problems in operating the plant, especially in the operation of, and removal of the products from, the reactor. Also, there is a lesser tendency to produce saturated hydrocarbons with rhodium catalyzed reactions than when cobalt catalysts are used. A still further advantage of the rhodium catalyzed hydroformylation reaction is that existing equipment used for co~alt catalyzed reactions can be converted to rhodium ~
catalyzed resctions with relatively little capital investment.

It has been found that rhodium catalysts, without complexing agents, persist in remaining in the hydroformylation reaction product. Full separation and recovery of the rhodium is extremely difficult.

In the work-up, the Oxo raw product is usually depressurized in several stages by reducing the synthesis pressure, which typically is about 250 to 300 bar (25 x 103 to 30 x 103 kPa). This causes the release of the synthesis gas, which is dissolved in the raw product. Once the dissolved synthesis gas is given up, the pressure can be further reduced to normal atmospheric pressure. Generally, the depressurized raw product is then distilled to obtain the desired product.

However, there are several drawbacks to distillation. It must be re~embereZ tnat the aldehydes and alcohols formed during the hydroformylation reaction are thermally sensitive.
This is especially so regarding the organic products of larger molecular weight, i.e. over 5 carbon atoms, which require higher distillation temperatures. Furthermore, under those conditions, it has been found that the rhodium catalysts decompose resulting in substantial catalyst losses.

Furthermore, the precious metal is homogeneously dissolved in the raw product in a concentration of only a few ppm. Further difficulties can also arise owing to the fact that, during depressurization, the rhodium is converted to its metallic form or forms polynuclear carbonyls. Whatever form the catalyst metal takes when present during distillation, a heterogeneous system is formed which consists of (a) the liquid organic phase and (b) the solid phase containing rhodium or rhodium compounds. Therefore, before purification or further processing of the reaction product (distillation), the dissolved rhodium compounds must be removed.

It has been proposed to separate and recover rhodium from hydroformylation reaction products by extracting the raw product with a complexing agent. It should be understood that "raw product" is intended to mean that mixture resulting from the hydroformylation reaction after depressurization to about atmospheric pressure and any necessary cooling has occurred.

According to one preferred embodiment of the procedure, the complexing agents used are sulonates and carboxylates of organic phosphines having the general formula:

~(X M) \

Yn1 ~' (X M)m P ~ Ar 2 ~ 1~

Ar ~X M) \ ` I
-Y
n3 wherein ~rl, Ar2 and Ar3 each represent a phenyl or naphthyl group; yl~ y2 and Y3 are each independently a s~raight or branched alkyl having 1 to 4 carbon atoms, alkoxy, halogen, OH-, CN-, ~2-~ or RlR2N-, where Rl and R2 each represent a straight or branched alkyl having 1 to 4 carbon atoms; Xl, x2 and X3 are each a carboxylate (COO~-) and/or a sulfonate (SO3-); ml, m2 and m3 are the same or different whole numbers from O to 3, the sum of ml, m2, and m3 being at least 1; and nl, n2, and n3 are the same or different whole numbers from O to 5. M is an alkali metal ion, an equivalent of an alkaline earth metal ion or zinc ion, ammonium, or quaternar~- ammonium ion with the general formula N(R3R4R5R6)+ wherein R3 R4 R5 and R6 independently selected from straight or branched alkyls having 1 to 4 carbon atoms. In one preferred embodiment, Arl, Ar2, and Ar3 are each a phenyl group;
Xl, X2, and X3 are each a sulfonate group; and ml, m2, and m3 are each independently O or 1, provided at least one of ml, m2 and m3 is 1.

The complex compounds formed from rhodium and the sulfonates or carboxylates of organic phosphines are water-soluble. Thus the rhodium can be extracted from the Oxo raw product, i.e. the organic phase, with an aqueous solution of the substituted phosphine. The rhodium thereby passes into the aqueous phase, which can be separated from the organic product mixture by simple decanting. By cycling the solution of the complexing agent, high rhodium concentrations can be achieved in the aqueous phase.

DES 26 27 354 has described the use of water soluble rhodium complexes of triarylphosphines as catalysts. The catalyst naturally migrates to the aqueous phase allowing separation of major amounts of the catalyst from the desired product by mere decantation or other separation methods not involving deleterious heating steps.

Even with the extracting complexing agent or the complexed catalyst, it has been found that the rhodium contained in the product mixture is still insufficiently recovered therefrom.

X

. 1338869 Additionally, when higher olefins are used as starting materials, conversions drop appreciably thereby decreasing the economic viability and worth of the process on a commercial scale. This drop in activity is quite understandable, since the hydroformylation reaction t~kes place in the aqueous phase and the lligher olefins are less and less soluble therein.

D~ 31 35 127 Al discloses conducting the hydroformylation reaction with aqueous and organic phases which are either immiscible or only slightly miscible with each other. .Although solubilizers are mentioned, the reaction is limited to rhodium complexes with monosulfonated triaryl phosphine or monocarboxylated triarylphosphine. This limited application i8 a severe drawback as it is well known that monosulfonated triaryl phosphines have extremely short life spans, making them unsuitable for recycling without extensive workup.

One ob~ect of the present invention i8 to provide an improvement in a process for the production of aldehydes by hydroformylation. Another object is to provide a process for rhodium recovery.

In one aspect, the invention provides, in a process for the production of aldehydes by hydroformylation by reaction of an olefin, carbon monoxide and hydrogen in the presence of water, the improvement comprising effecting the reaction in the presence of a guaternary ammonium solubilizer of the formula A--~ ~C E~-~p .~ (II) wherein A is a straight or branched alkyl, alkoxy, hydroxyalkyl, each having 1-25 carbon atoms, substituted or unsubstituted aryl having 6-25 carbon atoms, or R7CoNHCH2CH2CH2- wherein R7 is a straight or branched alkyl having 5-11 carbon atoms, B is a straight or branched alkyl of 1 to 25 carbon atoms, substituted or unsubstituted aryl having 6 to 25 carbon atoms or G~)-hydroxyalkyl having 1-4 carbon atoms, C and D are each independently chosen from straight or branched alkyls of 1 to 25 carbon atoms or ~-hydroxyalkyl having 1 to 4 carbon atoms, or C

and D, together with the bridging N, form a 5 or 6 membered heterocyclic ring, and E is selected from chloride, bromide, iodide, sulfate, tetrafluoroborate, acetate, methosulfate, benzene sulfate, alkylbenzene sulfate, sulfonate, toluene sulfonate, lactate, and citrate and a water-soluble complex of rhodium and a trisulfonated triarylphosphine of the formula ( X ~ )m I

yi"l ~(X2~),.,2 Y2"2 (I) ~ Xl.u~m3 -7a-wherein Ar1, Ar2 and Ar3 are individually selected from the group consisting of phenyl and naphthyl, yl/ y2 and Y3 are individually selected from the group consisting of alkyl and alkoxy of 1 to 4 carbon atoms, halogen, hydroxy, cyano, nitro and ~R
- N

and R1 and R2 are individually alkyl of 1 to 4 carbon atoms, X1, x2 and X3 are individually selected from the group consisting of carboxylate (COO-) and sulfonate (-So3-), m1, m2 and m3 are 1, n1, n2 and n3 are individually integers from O to 5, M is selected from the group consisting of alkali-metal, alkaline earth metal, zinc, -NH3, quaternary ammonium N(R3R4R5R6) +, R3, R4, R5 and R6 are individually alkyl of 1 to 4 carbon atoms.

-7b-The invention essentially resLdes in a process for the recovery of rhodium from mixtures in general, with specific application to reaction product mixtures resulting from hydroformylation reactions. One phase of the invention co~prises extracting a mixture containing rhodium with an aqueous solution having both a rhodium complexing a8ent and a solubilizer. A second phase of the invention is conducting the hydroform~lation reaction in the presence of the complexing agent and solubilizer.

The complexing agent is preferably a triaryl phosphine carboxylate ~r sulfonate, expecially those having Formula I
above. The complexing agent and solubilizer may be present in the hydroformylation reaction medium before the reaction begins or added during its progress.

In addition to promoting the extraction of rhodium from the organic reaction products, the solubilizers, in the presence of the trisulfonated or tricarboxylated triaryl phosphine complexes of rhodium yield consistantly high conversions and selectivities while avoiding catalyst decomposition. In this connection the phosphines are those of Formula I above but the sum of ml, m2 and m3 must be at least 3.

The solubilizers of the invention are understood to be substances or mixtures of substances which are compatible w~th both the aqueous and the organic phasc and, in partlcular, are solu~le in both phases at elevated temperatures. Such : ~3 -8- ~

-~ 1338869 substances are known and are also called phase transfer, surface-active or amphiphilic reagents or tensides.

Their particular effect is that they alter the physical properties o~ the contact surfaces between the two liquid phases and, thus, accelerate the transfer of the aqueous extracting agent to the product phase and the rhodium from the product phase to the aqueous complexing agent phase.

The use of the solubilizer simpliies extraction and reduces the amount of equipment necessary. With the new process it is possible to recover more than 95% of the rhodium contained in the product phase. Hence, one of the most important prerequisites for the technical realization of rhodium catalyzed hydroformylation, the separation of rhodium from the product is achieved. In this connection it is particularly advantageous that the solubilizer have no negative affect on the activity of the catalytically-active metal;
hence, no special work-up or activation steps are required.
However, variations requiring work-ups of differing degrees will be apparent to those in the art and are not excluded from the scope of the invention.

Examples of anionic solubilizers which can be used in the process according to the invention are salts of carboxylic acids having 8 to 20 carbon atoms, in particular of saturated fatty acids with 12 to 18 carbon atoms such as lauric, myristic and stearic acids. Alkyl sulfonates and alkyl aryl sulfonates, such as alkyl benzene sulfonates and alkyl naphthalene sulonates are also anionic solubilizers within the scope of the invention.

Amines whose highermolecular group is bonded to the nitrogen atom, either directly or via a heteroatom, can be used as cationic solubilzers. Examples of the first group of the above-mentioned compounds are octadecyldiethylamine, octadecylethanolamine, lauryldipolyglycolamine and 2-heptadecylimidazoline hydrochloride. The second group contains, in particular, compounds with hydrolysis-stable ether groups such as octylphenoldiethylamine ethylglycol ether.

:
Quarternaly ammonium compounds, especially ammonium salts, are particularly suitable cationic solubilizers. Compounds of Formula II

_ / B
A - N - C E(-~p II
- \ D
--~ .

have been found to be particularly suitable. In this formula, A is selected from (a~ straight or branched alkyl, alkoxy, hydroxyalkyl (especially ~-hydroxyalkyl), each having preferably 1-25 carbon atoms, (b) substituted or unsubstituted aryl having 6 to 25 carbon atoms, or (c) R7-CoNH-CH2-CH2-CH2, where R7 is a straight or branched alkyl having S to 11 carbon atoms; B is a straight or branched alkyl having 1 to 25 carbon atoms, substituted or unsubstituted aryl having 6 to 25 carbon atoms, or i .

~ -hydroxyalkyl having 1-4 carbons atoms; C and D are the same or different and are selected from (a) straight or branched alkyl groups preferably having 1-25 carbon atoms, or tb) ~ -hydroxy alkyl having 1 to 4 carbon atoms, or C and D, together with the bridging N, form a five or six-membered heterocyclic ring; E denotes chloride, bromide, iodide, sulfate, tetrafluoroborate, acetate, methosulfate, benzene sulate, alkyl benzene sulfate, toluene sulfonate, lactate or citrate, and p is the number of charges on E.

The methosulfates, sulfonates and lactates are preferred as anions because of their relatively low corrosive action.
Examples of suitable cations include stearyltrimethylammonium, phenyltrimetnylammonium, trimethyl-l-phenylammonium, benzyltrimethylammonium, dimethylbenzyldodecylammonium, cetyltrimethylammonium, myristyltrimethylammonium, dodecylpyridinium, stearylamidomethylpyridinium, cetyldimethylbenzylammonium, distearyldimethylammonium, lauryltrimethylammonium, benzyltriethylammonium, N-(3-trimethylammoniumpropyl)-n-heptanoic acid amide methosulfate, N-( ~-trimethyl- -ammoniumpropyl)-n-nonanoic acid amide methosulfate and dodecyl-tris- ~-hydroxyethylammonium.
..

- The neutral or non-ionoic solubilizers are, in p~rticular, adducts of ethylene oxide, such as alkylpolyethylene glycols (obtained by the addition of higher molecular alcohols to ethylene oxide), alkylphenylpolyethylene glycols (obtained by the addition of phenols to ethylene oxide~ and acylpolyethylene glycols (obtained by the addition of fatty acids to ethylene oxide). Polar solubilizers such as sulfolane and ,,~ ~

dimethy~sulfoxide are also suitable.

It is advantageous if the solubilizer contains both polar and non-polar molecular components so that the required activity for both the aqueous and the organic phases is ensured. In particular, the solubilizer should be distributed that means solved preferably in the aqueous phase and only to a lesser extent in the organic phase. The solubilizers can be used alone or as mixtures. --The concentration of the solubilizer in the aqueoussolution is about 0.005 to about 10% by weight based on the solution, preferably about 0.1 to about 2.5% by weight and most preferably about at least 0.5% by weight. Concentrations above 2.5% by weight can increase foaming tendency, to a greater or lesser extent, depending on the selected solubilizer, thus impairing rapid phase separation.

The process according to the invention is used with particularly great success for the separation and recovery of rhodium from the products of hydroformylation of both terminal and non-terminal branched olefins with at least 4 carbon atoms. Fven greater results are obtained with olefins having more than 5 carbon atoms such as i-heptene, diisobutylene, tri-and tetrapropylene or the mixture of C8-olefins sold under the trade name Dimersol. Naturally, the process can also be employed for the hydroformylation of unbranched terminal and non-terminal olefins; however the absolute rhodium concentrations in these reactions are generally lower to start with. 1338869 The uncomplexed rhodium catalyzed hydroformylation reaction is generally c~rried out at about 250 to about 300 bar and 120C to 150C. The complexed rhodium catalyzed reaction may be conducted at about 1 to about 200 bar, preferably about 10 to about 100 bar, and more preerably at about 10 to about 50 bar. Suitable temperature ranges are generally about 20C to about 150C, preferably about 50C to about 120C.

The complexed catalyst can be added to the reaction mixture in a preformed state, or formed in situ. The complex may even be formed in the presence of the olefin reactant. Uncomplexed rhodium catalyst may be used as finely distributed rhodium metal; water soluble rhodium salts, such as the chloride, the sulfate, or acetate; organically soluble compounds such as the 2-ethylhexanoate; or insoluble compounds such as the oxide.
The rhodium concentration in the aqueous catalyst solution should be about 10 to about 2000 ppm relative to the solution.

The phosphine complexing agent is preferably used in an amount of 1-1000 mole, more preferably 2-300 mole, and most preferably 2-100 mole, of phosphine compound per g-atom of rhodium.

The pH of the catalyst solution can vary over wide ranges.
Generally, it should be between 2 and 13. Preferably, the pH
is 4-10. The synthesis gas ratio can also vary over wide ranges. Any proportion generally utilized in hydroformylations reaction is suitable. The most preferred volume ratio is carbon monoxid~:hydrogen of about 1:1.

The remaining organic product phase, which is almost free of rhodium after the pllase separation, is washed with water to remove the residual extracting or complexing agent, rhodium, and solubilizer; it can then be sub~ected to the usual distillation work-up if desired. The water used for washing can be recirculated. Since the Oxo raw product continually removes a small amount of water rom the complexing agent solution, part of the wash water stream can be directed into the extraction stage to replace water losses and thereby prevent the complexing agent solution from becoming too concentrated. This amount of water is replaced in the washing stage or at any other convenient point by the addition of fresh water.

The aqueous phase, containing rhodium in hi8h concentration, is fed into the reaction mixture, either directly or cleaned and concentrated, as a catalyst solution.
It is also possible to separate the rhodium compounds which, but for the instant process, would be barely soluble or insoluble in water, e.g. in the form of rhodium-2-ethylhexanoate, and to re-use them as catalysts.

In the following examples various embodiments of the invention are described; the claimed process is not, however, limited to these embodiments.

Examples . ,, ,~

~.
,:~'.' .

In the Æxamples 1 to 8, raw isooctylaldehyde obtained by the hydroformylation of i-heptene cooled down to 20 to 25C and stored for several hours is used as the mixture from which rhodium is to be extracted. Examples 1, 3, 5 and 7 (the art) refer to rhodium extraction without the addition of a solubilizer; in Examples 2, 4, 6 and 8 (the invention) a solubilizer is used. In ~xamples 9 to 12, the separation of rhodium from various hydroformylation products is described.
No solu~ilizer ;s used in Examples 9 and 11, while one ;s used in Examples 10 and 12.

The abbreviation TPPTS stands for triphenylphosphine trisulfonate. All concentrations are given in % by weight.

Example 1 (comparison) In a flask fitted with a stirrer? 200 g of raw isooctylaldehyde containing 34.9% C7 hydrocarbons (mainly heptene), 62.7% isooctylaldehyde, 2.2% isooctylalcohol, 0.2% higher boiling substances, and 3.9 ppm rhodium are mixed with 20 g of a 0.1% aqueous sodium TPPTS solution.
The molar ratio of phosphorus to rhodium is 5:1. The two phases are intensively stirred for 5 minutes at 50C. After completion of the stirring, the two phases separate within 12 seconds, without an emulsion being formed. The organic Oxo raw --l~

product still contains 1.1 ppm rhodium, corresponding to a rhodium separation of 72%.

Example 2 Example 1 is repeated except that 0.1 g of cetyltrimethylammonium methosulfate is added to the aqueous TPPTS solution and the mixture stirred for 1 minute. The organic Oxo raw product phase only contains 0.6 ppm rhodium corresponding to a rhodium separation o 85%.

Example 3 (comparison) Example 1 is repeated ~ut a 0.4% sodium-TPPTS solution iæ
used. The molar ratio of phosphorus to rhodium is 20:1. 1 ppm rhodium is left in the organic phase corresponding to a rhodium separation of 74%.

Example 4 The same procedure used in Example 3 is carried out except that 0.1 g dodecyltrimethylammonium sulfate is added to the aqueous TPPTS solution and the mixture stirred for 1 minute.
0.6 ppm rhodium are left in the organic phase corresponding to a rhodium separation of 85%.

Example 5 (comparison) Example 3 is repeated but the mixture is stirred at a temperature of 80 C instead of 50 C. The two phases separate in 9 seconds. 1 ppm rhodium is le~t in the raw product ~ ~ 1338869 corresponding to a rhodium separation of 74%.

Example 6 The same procedure as in Example 5 is carried out except 0.1 g pyridinium sulfate is also added and the stirring time is 1 minute. Phase separation takes place in 9 seconds. 0.5 ppm rhodium is left in the raw product corresponding to a rhodium separation of 87%.

Example 7 (comparison) In a round-bottom flask with an outlet at the bottom, a gas inlet capillary, and a stirrer, 1000 g of isooctyl aldehyde with the same composition as in Example 1 is repeatedly extracted, each time with 100 g of a 20% sodium TPPTS
solution. Synthesis gas tCO/H2 = 1: 1) is fed through the inlet capillary to saturate the mixture with CO and hydrogen and the mixture~is then intensively stirred at 80C and left to stand for a further 30 seconds. The aqueous phase is then drained through the bottom outlet and the organic phase treated again with the next 100 g of a 20% sodium TPPTS
solution. The extraction process is carried out a total of four times. On completion, there is only 0.6 ppm rhodium left in the organic phase, corresponding to a rhodium separation of 85%.

Example 8 Except that the extraction steps are carried out with a TPPTS solution which also contains 2~ benzyltrimethylammonium .

sulfate and the mixture is only stirred for 20 seconds, the procedure in Example 7 is repeated. After completion of the extraction steps only 0.3 ppm rhodium are left in the organic phase corresponding to a rhodium separation of 92%.

Example 9 (comparison) In an apparatus used in Example 7, 1000 g of raw propionaldehyde containing 96.3% propionaldehyde, 0.2% n-propanol, 1.4% ethylene + ethane, 2.1% higher boiling substances, and 9.6 ppm rhodium are treated in 5 extraction steps, each time with 100 g o 2~o sodium TPPTS solution at 86C. The rhodium content of the organic phase is 1 ppm after the first extraction (corresponding to a rhodium separation of 66%) and 0.6 ppm after the fifth extraction (corresponding to a rhodium separation of 94~).

Example 10 The same procedure used in Example 4 is carried out except that 2% cetyltrimethylammonium acetate is added to the aqueous TPPTS solution. The rhodium content of the organic phase after the first extraction is 0.6 ppm (corresponding to a rhodium separation of 94%) and 0.2 ppm after the fifth extraction ` 1338869 (corresponding to a rhodium separation of 98%).

Improved results are also obtained with continuous operation.

Example 11 (comparison) 450 g of a residue from the hydroformylation of a C20-C40 a- olefin mixture with a rhodium content of 17 ppm are extracted with 50 g of a 20% TPPTS solution in an autoclave at 100C. After cooling and phase separation, the rhodium content of the non-distillable organic phase is 10 ppm, corresponding to a rhodium extracti.on of 41%.

Example 12 Example ll is repeated except that the aqueous TPPTS
solution also contains 2.5% tetradecyltrimethylammonium lactate (based on tle solution). The rhodium content of the organic phase after extraction is 0.2 ppm, corresponding to a rhodium recovery of 99%.

The example show that rhodium is extracted more rapidly and thoroughly when a solubilizer is added. Example 12 also demonstrates the rhodium catalyst can be removed from the non-distillable Oxo raw products under mild conditions.

In the remaining Examples, the following terms are utilized to characterize system efficiency.

n/i ratio of n-aldehyde to i-aldehyde activity = mole aldehyde g-atom F~h x min productivity = g aldehyde cm3 catalyst solution x hours is the average value of the repetitive trials reported in a particular Table Example 13 is a comparative example which i6 carried out without the addition of solubilizer.

Example 13 (comparative example) a) Advance preparation of the catalyst 345 ml of an aqueous solution of trisodium-tri(m-sulfophenyl)-phosphine, with a content of 20.4% salt, and 400 ppm Rh, as rhodium acetate, are~placed in a 1 litre autoclave with a support for a dip pipe. Synthesis gas (C0/H2 volume ratio = 1:1) is compressed to a pressure of 25 bar (2.5 x 103 kPa). Then the reaction solution is treated for 3 hours with stirring at 125C with synthesis gas, during which time the active catalyst is formed. After the mixture 1338~69 has been cooled to about 30 C, stirring is stopped. After a settling period of 15 minutes the excess solution (~ 10 g) is forced out through the support and analysed. The rest of the solution remains in the autoclave.

b) Hydroformylation 170 g n-hexene-l are pumped into the solution prepared according to a) and the mixtue is stirred. At a constant pressure of 25 bar (2.5 x 103 kPa) the mixture is heated to 125C and kept at this temperature ~or 3 hours. Afterwards, the mixture is cooled to 30C and left to settle. The upper organic phase is forced out through the support; it is weighed (see Table 1) and subjected to gas chromatographic analysis.

Step b) is repeated three times in total, basically the same results being achieved in each case. The activity and productivity figures listed in Table 1 refer to the amounts of organic and aqueous phase present in the autoclave. The specific weight of the aqueous phase is 1.1304.

Table 1 1338869 Number of 1 2 3 4 0 hydroformylations conversion(% acc. 22 18 18 16 18 to GC ) n/i ratio 98/2 98/2 98/2 98/2 98/2 organic phase (g) 153 167 172 175 167 aqueous phase in 346 344 343 342 344 the reactor (g) activity 1.22 1.09 1.13 1.02 1.11 mol C7aldehydes g atom Rh x min productivity 0.037 0.033 0.0340.031 0.033 g C7aldehydes cm3 cat. sol. x h ~- 1338869 Example 14 Example 13 is repeated except that 9.75 g ( 2 . 5 GeW% ) tetradecyltrimethylammonium methosulfate are added to the aqueous catalyst solution according to the invention. The specific weight of the catalyst solution is 1.171.

The test results are compiled in Table 2.

Table 2 conversion 41 47 48 35 42 4 (% acc.to GC) n/i ratio 95/5 96/4 96/4 96/4 96/4 96/4 organic phase (9) 168 175 185 220 176 185 aqueous phase in 374 352 341 336 306 342 the reactor (g) activity 2.31 2.93 3.23 2.87 3.02 2.87 mol C7aldehydes g atom Rh x min productivity 0.072 0.091 0.102 0.089 0.094 0.090 g C7al dehydes cm3 cat. sol. x h Example 14 shows that activity and productivity are considerably improved -- from about 2 times to about 3 times -- by the addition of a solubilizer, without adversely affecting the selectivity to any appreciable extent.

In order to determine the phosphorus and rhodium discharge, the organic products of Example 14 are mixed, concentrated and analysed. 0.3 ppm rhodium and 4 ppm phosphorus are contained in the organic product.

In Examples 15 to 21, the effect of the different solubilizers is clearly shown. ~e results of five hydroformylations with the same catalyst solution are summerized in an average value shown in Table 3. The test conditions are the same as in Examples 13 and 14.

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O aJ

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a~
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C~J . ~ ~ ~ E ~ c o. o .
o O ., ~ E ~ E
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t~ o o s o E O
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. ~ .~ ~ E E ~ E rO
__ o:~, E ~U o ra E ~o ~ rO X
s ~ ~ I ~ ~ s .-- a ~ ~ a~ X ~ u~ r~
r-- C ~ ~ S ~ r~ C C ~J S ~
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-o 3 ~ ~ c ~r-- ~ S Er~ E E
~~) ~ O ~ ra O 1~ E > rO rO Or-- ~ ~ ~ r~
ro ~ ~_ ~ r~ ~ Or~ ~ ~I S~
r-- r-- ~ D ~ C ~ r-- ~ rO O t_~ r~ ra ~ ~-- r-- ~`~ ~ S
DCl O ~ a~ > O ~ E
aE - a~ ~ u > r~ E ~ ~Cl- O ~ ~CU ~ E
~_rO ~ OJ O C C ~ O ~ ~ ~ C ~ C a.1 x o V~ E O ~ s_ ~ rOra ~ O 11) ~
llJ Z ~ ro O O Ia ~ Or~r-- D ~O D ~

o r--l r~l r~l r--I r~ r~

In the following examples, the concentration of the water-soluble trisulfonated phosphine is reduced so that the content of tri(m-sulfonphenyl) phosphine sodium salt is 12.2%
by weight. Otherwise the same procedure as in Examples 13 to 14 is adopted. Again the average of five hydroformylations with the same catalyst solution is taken. The results are compiled in Table 4.

-.
N

N ~7 0 O~
In O
0~ N~ ~
~N ~~ O
N

O
N 1~ ~J O

~0 o ' I' C

a~
O
U~ ' ~~ .
C~lO ~C~l O

,_ O
- ~.1~ r~ N
. r .0 0 ~1 . _ ~ .
O O~ V~
~ O _C
O ~ ~
-r .. - ~,-- aJ
E E
o o s_ ~, 5 D D
~ a~ o ' E E
o I
~: ~ ~ o ~ ~- ~-C C
- ~ OO
3 ~ EE ~ c E E~ o u E
a,-- ,-- ~ E
E >, ~., ,_ ,~
~ ~ o ~x ~ ~>, aJ U
,-- o~ ~ ,~
OX X cn o D ~ ~ OJ C ~ NQJ a ~ o ~ s s a) ~ x 1-- > ~ E v~ .,-,_ , ~ c o a~
_ ~ ~e ~ a) ~ o ~_ ~ ~ s o ~ al x>, ~ ~~ ~~,~,-- v~ ~,_ . ,- ,- ~ ~ >, ~ ~~, s c>, ~ ~ :~, ,-- ~ ~ s~,c r~ ~ r-- r-- ~?
o .a ~ ~ ~ ~ ~cna~ s o ~
,~ ~.~. ~ .~ ~ .a ~-, EE
QJ ~ ~ ~ ~-- E ~ ~-- ~ O~ r~ r-- ,-c L ~ ~ o ~ o Cl O ~ ~ ~ ~ ~ ~ ~ ~ ~ Z
E
~ ~ C ~ o O C_~ ~. .. . . . . .
x o o o o~ E cn ~ E ~ C' ~u~

-- ~g~

Comparison of Tables 3 and 4 shows the influence of the rhodium/phosphorus ratio on the extent of conversion in the hydroformylation process. In Ta~le 4, the minimum activity, without solubilizer, is seen to be about 2. This is observed with a Rh/P ratio of about 1:50 and is about twice as high as that observed in Table 3 where the Rh/P ratio is 1:100.
Surprisingly, the increase in conversion achieved as the Rh/P
ratio drops is even more pronounced when the solubilizers of the invention are also present.

In order to determine the phosphorus and rhodium discharge the organic products of Example 24 are mixed, concentrated and analysed. 0.41 ppm rhodium and 6.63 ppm phosphorus are contained in the organic product.

Claims (10)

1. In a process for the production of aldehydes by hydroformylation by reaction of an olefin, carbon monoxide and hydrogen in the presence of water, the improvement comprising effecting the reaction in the presence of a quaternary ammonium solubilizer of the formula (II) wherein A is a straight or branched alkyl, alkoxy, hydroxyalkyl, each having 1-25 carbon atoms, substituted or unsubstituted aryl having 6-25 carbon atoms, or R7CONHCH2CH2CH2- wherein R7 is a straight or branched alkyl having 5-11 carbon atoms, B is a straight or branched alkyl of 1 to 25 carbon atoms, substituted or unsubstituted aryl having 6 to 25 carbon atoms or .omega.-hydroxyalkyl having 1-4 carbon atoms, C and D are each independently chosen from straight or branched alkyls of 1 to 25 carbon atoms or .omega.-hydroxyalkyl having 1 to 4 carbon atoms, or C
and D, together with the bridging N, form a 5 or 6 membered heterocyclic ring, and E is selected from chloride, bromide, iodide, sulfate, tetrafluoroborate, acetate, methosulfate, benzene sulfate, alkylbenzene sulfate, sulfonate, toluene sulfonate, lactate, and citrate and a water-soluble complex of rhodium and a trisulfonated triarylphosphine of the formula wherein Ar1, Ar2 and Ar3 are individually selected from the group consisting of phenyl and naphthyl, Y1, Y2 and Y3 are individually selected from the group consisting of alkyl and alkoxy of 1 to 4 carbon atoms, halogen, hydroxy, cyano, nitro and and R1 and R2 are individually alkyl of 1 to 4 carbon atoms, X1, X2 and X3 are individually sulfonate (-SO3-), m1, m2 and m3 are 1, n1, n2 and n3 are individually integers from 0 to 5, M is selected from the group consisting of alkali-metal, alkaline earth metal, zinc, -NH3, quaternary ammonium N(R3R4R5R6) +, R3, R4, R5 and R6 are individually alkyl of 1 to 4 carbon atoms.

2. The process of claim 1 wherein said reaction takes place at a pressure of about 1 to about 200 bar and a temperature of about 20°C to about 150°C.

3. The process of claim 1 wherein A is selected from methyl, ethyl, propyl, stearyl, phenyl, benzyl, dodecyl, cetyl, myristyl, stearyl carbonyl, lauryl, heptanoic acid amido propyl, and nonanoic acid amido propyl;
B is selected from methyl, ethyl, hydroxyethyl propyl, phenyl, benzyl;
C and D are each independently selected from methyl, ethyl and hydroxyethyl; or C and D combine to form, with the bridging N, a pyrrole, pyridine or morpholine ring.

4. The process of claim 1 wherein A is selected from straight or branched alkyl having 8-16 carbons and substituted or unsubstituted aryl having 10-14 carbon atoms.

5. The process of claim 1 wherein said solubilizer is present in an amount of 0.5%-10% based on said aqueous solution.

6. The process of claim 1 wherein said olefin has at least 5 carbon atoms.

7. The process of claim 1 wherein said phosphine is present in an amount of about 1 to about 1000 mole per g-atom of rhodium

8. The process of claim 7 wherein said phosphine is present in an amount of 2-300 mole per g-atom of rhodium.

9. The method of claim 1 wherein said catalyst is introduced in a solution having a pH of about 2 to about 13.

10. The method of claim 9 wherein said pH is 4-10.