MXPA97002979A - Procedure for the hydroformilation of compounds olefinically not satura - Google Patents

Abstract

The present invention relates to a process for the hydroformylation of olefinically unsaturated compounds, by which the reaction takes place in a first reaction step in a system of water-soluble organic phosphorus compounds III in rhodium compounds containing complex bonds as catalysts at pressures of 0.4 to 10 MPa and burned gas is formed, further characterized in that the burnt gas is fed from the first reaction passage to a second reaction step, in which the residual amounts still present in the burnt gas of the olefinically unsaturated compounds in a homogeneous reaction system in the presence of complex rhodium compounds with organic phosphorus III compounds as catalysts at pressures of 15 to 40 M

Description

PROCEDURE P Rfl Lfl HYDROFORMILFlATION OF OLYFINICALLY UNSATURATED COMPOUNDS MEMORY OF THE INVENTION The invention relates to an improved process for the hydroformylation of olefinically unsaturated compounds in the presence of a water-soluble aqueous catalyst solution which contains complex rhodium-based compounds and, in particular, the use of oleates. they are not formed, they escape with the burned gas from the hydroformylation zone. The reaction of the compounds containing olefinic double bonds, with carbon monoxide and hydrogen, is the feasible technical procedure for the production of aldehydes (oxosynthesis). The process is not limited to the introduction of olefinic hydrocarbons, but also refers to exit materials, which in addition to the double bonds still exhibit functional groups, preponderantly those which remain unchanged under reaction conditions. Classical oxosynthesis works with cobalt as a catalyst. Its effectiveness is based on the formation of cobaltocarbombo compounds or the action of hydrogen and carbon monoxide at pressures greater than 20 MPa and temperatures of about 120 ° C and higher over cobalt me + alico or cobalt compounds. In the last 30 years cobalt was increasingly replaced with rhodium as a catalyst. The platinum metal is introduced as a complex compound which, in addition to carbon monoxide, preferably contains phosphines as ligands. Rhodium allows working at low pressures as a catalyst, and higher yields are also achieved and the most valuable unbranched products are preferably formed for further processing if the straight chain ends are pulled out. A further improvement of the oxosynthesis denotes the transition of homogeneously dislodged catalysts in the reaction medium, that is to say in the introduction material and in the transformation product, to aqueous catalyst solutions, which are present in their own phase separated from the introductory material and the transfer product. This variant of the reaction is described for example in DF-I) ~ 2fi 27 354. Its most particular advantage is the easy separation of the reaction product and the catalyst, which takes place considerately, without the application of the steps of the thermal process and therefore avoid losses, which occur through the consecutive reactions of the aldehydes originated. In addition, very high yields are obtained and with the use of more unbranched extreme oleins, very predominantly N-aldehydes are obtained. For reasons of economy of the procedure, particularly to avoid large reactors and long reaction times, the formation is not carried out until the complete consumption of the olefinically unsaturated compounds, but often enough with the change of only 60 to 95% of the output product for the desired final compound. In the burned gas that flows into the drying zone, there is also, in addition to the carbon monoxide and the abundant hydrogen, an olefinic converted form material. Whereas before, these valuable materials were often renounced, now we try to take advantage of them as completely as possible. This effort led to the development of a series of distinctly configured procedures. According to a known process (cf. EP 0 111 257 Bl), the burnt gas coming from a hydroformation step in the olefme is reacted with carbon monoxide and hydrogen in the presence of a catalyzed aqueous solution containing complex compounds of rhodium at low pressure to make reaction, in a second step according to the classic oxoprocediriento at high pressure and in the presence of cobalt catalysts. This procedure has given very good results in practice, particularly when there was the possibility of combining a modern hydroformylation facility with an existing facility that works with cobalt as a catalyst. According to a form of work (compare EP 01 88 246 Bl), they are connected one behind another doe steps of hydroformylation catalyzed with rhodium. In the first step, by means of the return of the liquid or the olefmic gas, carbon monoxide and hydrogen are transformed in the presence of a soluble complex catalyst of rhodium and phosphorus, in free phosphorus ligand and condensation products of higher boiling aldehyde . The burned gas contains olefin, if appropriate aldehyde, furthermore hydrogen, carbon monoxide and alkane-derived product, is conducted to a secondary hydroformylation process catalyzed by decoupled rhodium, ie carried out from the first step separately in which it reacts, by returning the liquid or gas, the burned gas together with the carbon monoxide and hydrogen aggregates. This process is limited to carrying out the hydroformylation both in the first and in the second step in the presence of a homogeneous dissolved catalyst in the reaction mixture. The considerable coincidence of the reaction conditions, particularly of the catalyst system in the main reaction and in the subsequent reaction, excludes with great certainty the possibility that the gas burnt from the first step contains components which can affect hydroformylation in the second step. The transfer of the two-step transformation, carried out in homogeneous phases, to a process, which employs aqueous catalytic solutions in the first and second steps, is not possible with the jusable technical expense.

It is unsuccessful because the burnt gas from the primary phase due to high consumption contains olefin in low concentration. Its preparation in the secondary step therefore requires, in the introduction of the catalyst system dissolved in water, either prolonged reaction times or special technical devices to reduce the reaction time and still obtain a high consumption. There was therefore a commitment to develop a process that would allow to transform under economically justifiable conditions the olefinic compounds that are in the burned gas of a reaction of hydroforming Lacion carried out with an aqueous catalyst solution, in carbomlo compounds. The invention is based on a process for the hydroformylation of olefinically unsaturated compounds, in which the reaction takes place in a first reaction step in a heterogeneous reaction system by the use of an aqueous solution, of rhodium compounds containing compounds of phosphorus III organic soluble in water with complex bond as catalysts, under pressures of 0.4 to 10 MPa and burned gas is formed. It is characterized in that the burnt gas from the first reaction step is conducted to the second reaction step, in which residual amounts still present in the burned gas of the olefinically unsaturated compounds are converted into a homogeneous reaction in the presence of complex compounds of Rhodium with organic phosphorus III compounds as catalysts under pressures of 15 to 40 MPa. The new procedure ensures that most of the olefinic compounds contained in the burned gas are hydroformylated, not transformed in the first step. In this way, more than 98% of the output materials applied to the desired carbonyl compounds are frequently transferred, with respect to the entire process, where the consumption essentially depends on the kind of introduction material and the reaction conditions. It has to be emphasized that no profitable derivative products are formed or hardly formed except in a completely insignificant quantity. The high efficiency of the process according to the invention was not foreseeable. At the same time, it must be taken into account, among other things, that the olefinic compounds are present in the burnt gas in remarkable dilution. For example, in the hydroformylation of lower olefins, the ratio of the unreacted olefinic introduction material to the burned gas is only 20 to 50% by weight. Such concentrations are opposed in this reaction class to a considerable transformation of the unsaturated leaving compound. The impurities extracted with the burnt gas from the first step of the reaction, in this case among other things, are concerned with degradation products of the catalyst system such as tappends and water, with the solvent for the catalyst in the first step, do not surprisingly affect the Catalyst efficiency in the second step. Such behavior was not to be expected, particularly because the organic derivatives of hydrogen sulfide are known as catalyst poisons. At the same time it must be taken into account that the reactants are hardly soluble in water, as a consequence of which they can not enter the catalytic solution of the first reaction step and therefore also not affect the catalyst. On the contrary, the mercaptans are concentrated because of their good solubility in organic media in the homogeneous catalyst-containing reaction mixture of the second reaction step. In addition, it also forms water with complex rhodium compounds and can therefore replace the organic phosphorus ligands in rhodium complexes homogeneously dispersed at least in part with the formation of catalytically inactive substances. The first reaction steps of the new process are carried out as a heterogeneous reaction in a two-phase system, which reaction is described for example in DE-B-26 27 354. This process is characterized by the presence of an organic phase, which contains the olefinic starting material and the reaction product, and of an aqueous phase, in which the catalyst is dissolved. As the catalysts, water-soluble rhodium complex compounds are added, which contain water-soluble phosphorus III compounds or ligands. Some examples of water-soluble phosphorus compounds III, which are formed with the complex rhodium compounds, are triarylphosphines, trialkylphosphines and arylated or alkylated diphosphines, the organic residues of which contain sulphonic acid groups and carboxyl groups. Its production and application are known, for example, from US-B 26 27 354, EP 0 103 810 Bl, EP 0 163 234 Bl and EP 0 163 234 A1. Other suitable groups of compounds are the sulfonated or carboxylated organic phosphites as well as the compounds heterocyclics of the triple bond phosphorus (cf. for example EP 0 575 785 A1, EP 0 646 588 Al). The conditions, in which the transformation takes place in the first reaction step, can be varied within wide limits and adapted to the individual facts. They depend among other things on the output material, the chosen catalyst system and the degree of transformation desired. Usually the hydroformylation of the exit materials is carried out at temperatures of 50 to 180 ° C. Preferably, temperatures of 80 to 140 and particularly of 100 to 130 ° C are maintained. The total pressure fluctuates on a scale of 0.4 to 10 MPa, preferably of 1 to 6 MPa and particularly 1.5 to 5 MPa. The molar ratio of hydrogen to carbon monoxide ranges from 1:10 to 10: 1, mixtures containing hydrogen and carbon monoxide in the ratio of 3: 1 to 1: 3 and particularly of approximately 1: 1 being particularly suitable. The rhodium concentration is from 20 to 1,000 ppm by weight, preferably from 50 to 500 ppm by weight and particularly from 100 to 300 ppm by weight, in each case with respect to the aqueous catalyst solution. Although it is possible to add catalyst as the complex compound of phosphorus and rhodium synthesized stachyne, it is usually worked in the presence of abundant phosphorus ligands, ie ligands that have not contracted any complex bond with rhodium. For each mole of rhodium, preferably 3 to 200 moles of phosphorus are applied in the form of an organic water-soluble phosphorus compound. Molar ratios of rhodium to phosphorus on a scale of 1:50 to 1: 100 have proved to be particularly effective. The complex rhodium and phosphorus catalyst does not need to be uniformly synthesized, but may consist of a mixture of complex rhodium and phosphorus compounds, which are distinguished by the class of phosphorus ligands. In the same way, the free phosphorus ligand contained in the aqueous solution of a mixture of different water-soluble phosphorus organic compounds can be synthesized. The catalyst is usually formed from the rhodium or rhodium compound, organic phosphorus compound and synthesis gas under the reaction conditions of the hydroforming in the reaction mixture. However, the second reaction step can also be fed preformed, ie produced separately. Also with r-spec to the technical configuration of procedure and of the apparatuses of the first step of the new procedure one can be conducted within wide limits. An embodiment of hydroformylation with the use of an aqueous catalyst phase is described in EP 0 103 810 Bl. It has been convenient to handle the Lizadora taster solution in a cycle and, if necessary, compensate for the catalyst losses that occur with the new catalyst supply "To increase the consumption per unit of time of the olefinically unsaturated compounds, which are only a little soluble in the aqueous catalyst solution, it may be recommended to add a phase transfer reagent (solvent) to this solution. It modifies the physical properties of the boundary surfaces between the two liquid phases and facilitates the transition from the organic reagent to the aqueous phase of the catalyst. As solvents, compounds are known whose hydrophilic groups are ionic (ammonium or cationic) or non-ionic. The active compounds with anions include the sodium, potassium or ammonium salts of the carbon acids, preferably those with 8 to 20 carbon atoms and particularly of the saturated fatty acids with 12 to 18 carbon atoms, furthermore alkyl sulphates, benzolsul alkyl inatoms and benzene alkyl phosphates. Some examples of cationic solvents are the salts of tetraal uilarnome and N-alkylpyridinium. The non-ionic phase transfer reagents do not dissociate in ions in aqueous solution. Among them are alkylpolyethylene glycols, alkylphenopolyethylene glycols, fatty acid alkylates and trialkylamino acids. In addition, amphoteric electrolytes such as ammocarbons, bet-ainae and sulfobetai a are applicable as solvents. The corresponding procedures are described, for example in EP 0 157 316 Bl. It is usually sought in the second reaction step to obtain as much as possible extensive use of the olefinically unsaturated compounds. In particular cases, however, it is also intended to achieve a more or less large partial consumption e. The burnt gas escaping from the first reaction step (flow of burned gas) is composed of burned gas that is extracted immediately from the reactor (reactor gas), to avoid a concentration of inert gases in the gas mixture that is driven in cycle and the gaseous components that take place with the separation of the catalyst solution and the crude reaction product in the phase separator (product burnt gas). The flow of burned gas consists essentially of unprocessed olefinic compounds, carbon monoxide, carbon dioxide, hydrogen and the hydrogenation products of the olefin. This mixture of gases is released without further intermediate treatment, particularly without purification, however, if necessary, after the addition with mixing of hydrogen alone or in a mixture with carbon monoxide as introduction material of a second hydroformylation step. The second reaction step is conducted independently of the first one. In it, the residual amounts present in the flow of burnt gas of the unsaturated oleate compounds are transformed in a homogeneous reaction system with carbon monoxide and hydrogen. The concept of homogeneous reaction system refers to a homogeneous solution formed essentially of solvent, catalyst, olefinically unsaturated compound and reaction product. Complex rhodium compounds, which contain phosphorus organic compounds III as ligands, are used as catalysts. Complex compounds of this nature and their production are known (compare for example US 3 527 809 Al, US 4 148 830 Al, US 4 427 286 Al, US 4,283 562 Al). They can be inserted as a uniform complex compound or also as a mixture of different complex compounds. The concentration of rhodium in the reaction medium fluctuates on a scale from about 1 to about 1,000 ppm by weight and is preferably from 10 to 700 pprn by weight. Particularly rhodium is used in concentrations of 25 to 500 ppm by weight, in each case with respect to the homogeneous reaction mixture. As in the first step, the complex compound of rhodium stoichiometrically formed can be used as a catalyst. It has been found convenient, however, to carry out the hydroformylation in the presence of a catalyst system of complex compound and free phosphorus ligand, ie abundant, which is no longer a part together with the remainder of a complex compound. The free phosphorus ligand can be the p same as the complex rhodium compound, but different ligands can also be inserted from it. r: i free ligand can be uniform compound or consist of a mixture of different organic phosphorus compounds. Some examples of complex rhodium and phosphorus compounds which can be applied as catalysts are described in US Pat. No. 3,527,809 Al. Preferred ligands in rhodium complex catalysts include, for example, triaphosphosphonates such as phosphatide, trialkyl phosphines more co o The tr? (n-oct 11) -fos fina, trilauplfosfma, tr? (c? clohex? 1) fosf ma, the alkylfeflfosfinas, cicloalquilfeml fosf as and organic diphosphites. Because of its easy availability, triphenylphosphate is used with special frequency. It usually rises The molar ratio of rhodium to phosphorus from 1: 1 to 1: 300, however the molar portion of phosphorus in the form of organic phosphorus compounds can also be high. Preferably rhodium and organically linked phosphorus are included in molar ratios of 1: 3 to 1: 200. With the use of triapl phosphines, the Rh / P molar ratios of 1:50 to 1: 150 If tnalkylphosphines are included as ligands, then the molar ratio of rhodium to phosphorus is preferably from 1: 3 to 1:20. The hydrofornylation reaction is carried out in the presence of a solvent. Solvents include organic compounds, in which the exit material, the reaction product and the catalyst system are soluble. Some examples of such compounds aromatic hydrocarbons such as benzene, toluene or xylene. Other common solvents are paraffin oil, ketone or ether. As particularly suitable solvents, the high-boiling condensation compounds of the aldehydes which originate as by-products in the hydroformylation have proved to be effective. The portion of the solvent in the reaction medium can be varied over a wide range of concentration and is usually from 20 to 90% by weight, preferably from 50 to 80% by weight, based on the reaction mixture. The reaction pressure in the second step of the complete process is in the range of 15 to 40 MPa. It has been found to be especially effective to observe pressures between 15 and 35 MPa, preferably 20 to 30 MPa. Such scales are uncommon for hydrophores in homogeneous systems and in the presence of complex rhodium compounds with organic phosphorus compounds, regardless of whether the transformation takes place in one or more steps. The volume ratio of hydrogen to carbon monoxide is from 1:10 to 10: 1, preferably from 1: 3 to 3: 1 and particularly 1: 1. The reaction temperatures rise in the second step of the new process from 50 to 160 ° C. Temperatures of 60 to 150 ° C and particularly of 75 to 140 ° C are preferred. As already mentioned, the reaction product is separated from the first reaction step in a phase separator of the aqueous catalyst solution which is reduced in the process. According to an effective embodiment, the crude aldehyde is passed on a counterflow column of Stppp with the new synthesis gas. The heat is then transferred to the synthesis gas, and the olefin compound is extracted from the crude product and conducted together with the heated synthesis gas recovered from the reaction. The ransformation product of the second step is separated from the catalyst by distillation. It can be combined with the product from the first step and then processed, for example, distilled. The distillation residue from the second step and containing catalyst is optionally recirculated after the addition of fresh catalyst and the extraction of the condensation products from the aldehyde in the course of the reaction in the reaction zone. The transformation of the straight-chain, unsaturated, olymphatically unsaturated compounds into the second reaction step, that is to say with the catalyst homogeneously dissolved in the reaction medium, gives as reaction product an aldehyde mixture which contains a higher portion. isocorn put as the product of the first step, ie the reaction with the use of a heterogeneous catalyst phase. It is therefore possible according to the new method, by selecting the olefin consumption in the first step, to adjust the portions of the n ~ and the isocomposite in the reaction product over the entire process to the current requirements. According to another embodiment of the process according to the reference, the n- and iso-compound ratio in the whole process can also be influenced by the addition of olefme to the mixture of burnt gases which are fed to the second step of reaction. Independent of the class of olefinically unsaturated introduction materials, the formation of consecutive products of molecularly higher aldehydes (dense oil) in the passage is very insignificant. The process according to the invention can be applied to olefinically unsaturated compounds of any structure. Accordingly, they are suitable as defned output material with both internal and external double bonds and also straight or branched chain olefins. In addition, olefins can still be substituted with functional groups, in particular those which do not change during the course of the reaction. The compounds which are multiple olefinically unsaturated as input materials are also suitable. Especially effective has been the procedure in the hydroforming of olefinically unsaturated hydrocarbon materials with 3 to 6 carbon atoms in the molecule, preferably propylene and isomeric butenes. The invention is explained in more detail in the following examples, however not limited to the embodiments described.

EXAMPLE 1 First Reaction Step In a reactor, under intense stirring, a synthesis gas pressure (CO: Ha = 1: 1) of 5 MPa and at a temperature of 122 ° C is produced from rhodium acetate and trifephosphinesulfonate sodium (TFFTS), the active catalyst, soluble in water, HRhCG (TFFTS) 3. The rhodium compound and the TFFTS are added in such an amount, so that the concentration of rhodium in the aqueous catalyst solution rises to 300 ppm by weight and the molar ratio of rhodium to phosphorus to 1: 100. On a distributor ring at the base of the reactor, preheated propylene is conducted to the reaction zone and the olefme is transformed therein with carbon monoxide and hydrogen at 122 ° C and 5 MPa. The flow of the product consisting of gaseous and liquid components is removed from the upper part of the reactor and fed to a phase separator, in which the separation of the aqueous catalyst solution of the crude organic reaction product and the burned gas takes place. of product. The burnt product gas is joined together with the burned gas from the reactor to the flow of burned gases. The burnt gas from the reactor is removed from the reactor to avoid a concentration of inert gases in the gas mixture that is driven in cycle. With additional cooling, a liquid condensate (condensate from burnt gases), consisting essentially of propylene and propane, is separated from the flow of burned gases. The catalytic solution that falls into the phase separator is pumped back to the reactor. The crude aldehyde is passed to a column which is then connected in counterflow to the synthesis gas. At this time the heat of the aldehyde is transferred to the synthesis gas and at the same time the flow of synthesis gas takes out the dissolved propylene and propane. The water that is returned to the catalyst cycle is separated from the aldehyde by the cooling. The propylene consumption is, according to the flow and the purity of the olefin, in the selected conditions between 81 and 91%. The ratio of n-al due to i-aldehyde amounts to approximately 20: 1.

Second Reaction Step The flow of burned gas and the burnt gas condensate from the first reaction step, if appropriate, by hydrogen and / or carbon monoxide and / or propylene, is reintegrated and compressed together with the catalytic solution at 21 MPa. and it is fed to the second reactor. The catalyst consists of condensation products of high-boiling aldehydes, in which the phosphatide (TFF) and the complex r-hatred compound HRhCO (TFF) a dissolve. The introduction mixture is introduced into the reactor with a velocity in the space of 0.5 V / V. h from the base. It has approximately the following compounds (all data in% by weight).

Hydrogen 2.20 Carbon monoxide 29.94 Carbon dioxide 0.31 Inert gases 1.29 Propylene 40.01 Propane 10.19 n-Butylaldehyde 6.98 Isobutyl aldehyde or 0.54 Butanols 0.77 Components C8 1.60 > Components C8 2.76 Tri-phenyl phosphine 1.21 Tri-phenyl-osphine oxide 0.50 Water 1.69 Sulfur traces The molar ratio of phosphorus to rhodium amounts to approximately 80: 1. The transformation of the reactants takes place at 132 ° C. 99% of the introduced propylene (that is to say of the unprocessed propylene in the first reaction step and in the case of propylene added to the flow of burned gas before the entrance to the second reactor) is transformed into aldehyde. The flow of product left in the second reactor is spread by means of a separator. In addition to a liquid phase, the aldehyde crude product, a gaseous phase, the spreading gas, is obtained, which is fractionally condensed with the separation of the residual aldehyde. The crude aldehyde is separated from the catalyst by distillation in a first column and removed in a second column in n-e-butylaldehyde. The catalyst, which descends as liquid waste, is fed mostly to the first column. Only a small partial flow is separated in such an amount, so that the concentration of the high-boiling aldehyde condensation products used as solvents for the rhodium catalyst in the second reactor-remains approximately constant. Under the selected conditions the ratio of n-aldehyde to i-aldehyde rises to 65:35.

EXAMPLE 2 First Reaction Step The transformation of the reactants into the first reaction step takes place in the same manner as described in Example 1.

Second Reaction Step The flow of burned gas and the condensate of gas burned if necessary by hydrogen and / or carbon monoxide and / or propylene are completed and transformed at a pressure of 25 to 27 MPa and a temperature of 130 ° C in an autoclave. For each 1,500 g of propylene, 80 rng of rhodium and varying amounts of tnlauryl phosphine are added, so that the ratio of rhodium to phosphorus is 1: 5, or 1:10. The results are collected in the following table. They are compared with the results obtained with the addition of Rh / TFF as a catalyst, CÜT2BQ

Claims (17)

NOVELTY OF THE INVENTION CLAIMS

1. Procedure for the hydrolyzing of olefinically unsaturated compounds, by which the reaction takes place in a first reaction step in a heterogeneous reaction system by the use of an aqueous solution, water-soluble organic phosphorus III compounds. in rhodium compounds containing complex bond as catalysts at pressures of 0.4 to 10 MPa and burned gas is formed, further characterized in that the burned gas is fed from the first reaction step to a second reaction step, in which the amounts are transformed residuals still present in the burned gas of olefinically unsaturated compounds in a homogeneous reaction system in the presence of complex rhodium compounds with organic phosphorus III compounds as catalysts at pressures of 15 to 40 MPa.

2. Method according to claim 1, further characterized in that the hydroformylation takes place in the first reaction step at temperatures of 50 to 180 ° C and a concentration of 20 to 1,000 ppm by weight, based on the aqueous catalyst solution, and the molar ratio of rhodium to phosphorus in the catalyst solution amounts from 1: 3 to 1: 200.

3. Method according to claim 1 or 2, further characterized in that the pressure in the first step is from 1 to 6 and par- ticularly from 1.5 to 5 MPa.

4. Process according to one or more of Claims L to 3, further characterized in that the temperature in the first reaction step is from 80 to 140 and particularly from 100 to 130 ° C.

5. Method according to one or more of claims 1 to 4, further characterized in that the concentration in the aqueous catalyst solution is from 50 to 500 and particularly from 100 to 300 pprn by weight.

6. Condority procedure with one or more of claims 1 to 5, further characterized in that the molar ratio of rhodium to phosphorus in the catalyst solution is from 1:50 to 1: 100.

7. Process according to one or more of claims 1 to 6, further characterized in that phosphines or sulfonated or carboxylated aliphatic, aromatic or mixed phthalic acid phosphines or phosphites are added together with water-soluble organic phosphorus compounds III.

8. Method according to one or more claims 1 to 7, further characterized by the hydroformylation in the second reaction step in the presence of a solvent at temperatures of 50 to 160 ° C and a rhodium concentration of 1 to 1,000 ppm by weight, relative to the homogeneous reaction mixture, and the molar ratio of rhodium to phosphorus rises in the reaction mixture from 1: 1 to 1: 300.

9. - Method according to claim 8, further characterized in that the pressure in the second step is from 15 to 35 and particularly from 20 to 30.

10. Process according to claim 8 or 9, further characterized p > or the temperature in the second reaction step is from 60 to 150 ° C and particularly from 75 to 140 ° C.

11. Method according to one or more of claims 8 to 10, further characterized in that the rhodium concentration in the second reaction step is from .1 to 700 ppm by weight and particularly from 25 to 500 ppm by weight, to the reaction mixture.

12. Method according to one or more of claims 8 to 11, further characterized in that in the second reaction step the molar ratio of rhodium to phosphorus in the reaction mixture is from 1: 3 to 1: 200.

13. Method according to one or more of claims 8 to 12, further characterized in that phosphines or aliphatic, aromatic or mixed aliphatic-aromatic phosphites are added as phosphorus organic compounds III.

14. Process according to claim 13, further characterized in that the organic phosphorus compound III is a triarylphosphine and the molar ratio of rhodium to phosphorus in the reaction mixture amounts to 1:50 to 1: 150. ? ">

15. - Method according to claim 1, further characterized in that the triethyl phosphine is tpfemlfosphine.

16. Process according to claim 13, further characterized in that the organic compound phosphorus Til is a pallet phosphine t and the molar ratio of rhodium to phosphorus in the reaction mixture amounts to 1: 3 to 1:20.

17. Process according to claim 16, further characterized in that the trialkyl phosphine is tpfeml phosphine.