MXPA99008458A - Procedure for the elaboration of oxo-upper alcohols from olefinic mixtures by hydroformilation in two eta - Google Patents

Abstract

The present invention relates to: A process for the preparation of higher oxo-alcohols from mixtures of isomeric olefins with 5 to 24 carbon atoms through a hydroformylation in two stages in the presence of a cobalt or rhodium catalyst increased temperature and pressure in which the reaction mixture of the first hydroformylation stage is selectively hydrogenated, the hydrogenated mixture is separated by distillation in crude alcohol and mainly lower boiling substances consisting of olefins, the latter material is passed to the second stage of hydroformylation, the reaction mixture of the second hydroformylation step is again selectively hydrogenated, the hydrogenated mixture is separated by distillation in crude alcohol and substances of lower boiling point, the crude alcohol is prepared at a higher level by distillation pure alcohol and at least a part of the substances of lowest point of boiling is removed in order to extract saturated hydrocarbons

Description

PROCEDURE FOR THE PREPARATION OF OXO-UPPER ALCOHOLS FROM OLEFINIC MIXTURES BY HYDROFORMILATION IN TWO STAGES The present invention relates to a process for the production of higher oxo-alcohols by the hydroformylation in two stages of olefinic mixtures, which includes a selective hydrogenation of the hydroformylation mixture. STATE OF THE ART Higher alcohols, especially those with 6 to 25 carbon atoms, as is known, can be made by catalytic hydroformylation (or oxo-reaction) of the mixture of olefins having one less carbon atom for later make a catalytic hydrogenation of the reaction mixture containing aldehyde and alcohol. They are used mainly as educts or salient substances to obtain softeners or detergents. The class of the catalyst system and the optimum reaction conditions for hydroformylation depend on the reactivity of the olefin used. The dependence of the reactivity of olefins, of their structure, has been described for example by J. Falbe, New Syntheses with Carbon Monoxide, Springer Verlag, Berlin, Heidelberg, New York, 1980, page 95ff. The different reactivity especially of isomeric octenes is also known (B.L. Haymore, A. van Hasselt, R. Beck, Annals of the New York Acad. Sci., 415 (1983) pages 159-175). The olefinic technical mixtures that are used as educts, which are salient substances for oxo-synthesis, contain olefinic isomers of the most diverse structures with different degrees of branching, a different position of the double bond in the molecule and possibly different numbers of carbon atoms. . This applies in particular to olefinic mixtures that have been generated by dimerization, trimerization or a more advanced oligomerization of the olefins with 2 to 5 carbon atoms or of other higher olefins easily accessible or, where appropriate, by co-oligomerization of the olefins. olefins mentioned. As examples for typical isomeric olefinic mixtures, which can be reacted through rhodium-catalyzed hydroformylation or preferably cobalt to obtain corresponding mixtures of aldehydes and alcohols, we mentioned the tripropenes and the tetrapropenes as well as the dibutenes, tributanes and tetrabutenes. The speed of the hydroformylation reaction decreases as the number of carbon atoms grows and also with the degree of branching. The reaction rate of the linear olefins can be 5 to 10 times greater than that of the branched isomers. Also the The position of the double bond in the olefin molecule influences the reactivity. The olefins with a double terminal bond clearly react in a faster way than the isomers with the double bond inside the molecule. Due to the different reactivity of the olefinic isomers, relatively longer reaction times are required in order to obtain as complete a conversion as possible of the olefins. But this reduces the yield in product as a result of certain secondary and consequential, undesirable reactions. The same occurs when it comes to shortening the reaction times by means of higher reaction temperatures. First of all due to the different reactivity of the isomers, it is difficult in the hydroformylation of olefinic mixtures to achieve high degrees of conversion and at the same time high degrees of selectivity. This is particularly applicable to hydroformylations that are carried out in a single stage. According to DE 32 32 557 Al, alcohols are prepared by hydroformylation in two stages of monoolefins having 3 to 20 carbon atoms. In the first reaction stage, the olefins are reacted with the use of a cobalt catalyst with conversion rates of 50% to 90% to obtain the aldehyde, the formation of alcohols being suppressed here. Then it is separated the cobalt catalyst of the reaction mixture and this material is hydroformylated again in a second step using a cobalt organophosphine complex as the catalyst. At the same time, the aldehyde formed in the first stage is hydrogenated in alcohol. A disadvantage in this process is that especially in the second hydroformylation step a considerable part of the olefins is hydrogenated instead of hydroformylated. BRIEF DESCRIPTION OF THE INVENTION A task of the present invention is to create a process for the production of higher oxo-alcohols from the corresponding olefinic mixtures that bind high conversion percentages with high selectivities and that also stand out for high space / time yields . An object of the present invention is therefore a process for the preparation of higher oxo-alcohols from mixtures of isomeric olefins with 5 to 25 carbon atoms through hydroformylation in two stages in the presence of a cobalt catalyst or of rhodium at increased temperature and pressure, in which the reaction mixture of the first hydroformylation step is selectively hydrogenated, the hydrogenation mixture is separated, in a distillation, in crude alcohol and in the case of low boiling consisting of olefins, this latter material is taken to the second stage of hydroformylation, again selectively hydrogenated "the reaction mixture of the second hydroformylation stage, again the hydrogenated mixture is separated by distillation in crude alcohol and a substance of low At the boiling point, the crude alcohol is processed to a greater degree by distillation over pure alcohol and at least a part of the low-boiling substance is removed to selectively obtain saturated hydrocarbons Advantageously the mixtures are freed from the hydroformylation catalyst of the pressure reaction relieved from both hydroformylation stages and before carrying out the selective hydrogenation DESCRIPTION OF THE INVENTION The process according to the invention can be carried out intermittently or advantageously in a continuous manner. procedural variants In Figure 1, as an example, the block diagram of an installation in which the procedure can be carried out in a continuous manner has been illustrated. In the first hydroformylation reactor 1, the olefinic mixture 2, synthesis gas (carbon monoxide and hydrogen) 3 is introduced as well as the catalyst 4. The pressure of the hydroformylation mixture 5 is relieved, the gas used to relieve the pressure 6 is removed (the unused synthesis gas) and the reduced pressure hydroformylation mixture 5 is released in the first catalyst separation 7 of the catalyst which, optionally after having been subjected to a replacement with the introduction of fresh catalyst, is recirculated to the first hydroformylation reactor 1. The hydroformylation mixture 8 released from the catalyst is conducted to the selective hydrogenation system 9 in which the alcohols are hydrogenated to alcohols. aldehydes as well as the by-products contained in the mixture, such as the acetals of the aldehydes and the esters of the alcohols, especially their formates. From the hydrogenation mixture 10, the low-boiling substances 12 are separated off in distillation 11, substances which are mostly composed of unreacted isomeric olefins and which are conducted to the second hydroformylation reactor 13, which is also It carries the synthesis gas 14 and the catalyst 15. A part of the low-boiling substances 12 is selectively withdrawn as remaining substances of low boiling point 16. The hydroformylation mixture 17 from the second hydroformylation reactor 13 is again subjected to to a pressure relief and the relief gas 18 is removed. The hydroformiladora mixture 17, with its pressure reduced, is released in the second catalyst separator system 19 of the catalyst 15, which, if necessary of new beads after being replenished, is recirculated to the second hydroformylator reactor 13 and which is passed as a hydroformylation mixture 20, devoid of catalyst, towards the selective hydrogenation system 9. There, this material is hydrogenated selectively together with that hydroformilating mixture 8, released from the catalyst and coming from the first hydroformylation reactor 1. The crude alcohol 21 withdrawn from the distillation, is further processed to achieve pure alcohol by means of another distillation not illustrated. The block diagram of an alternative consisting of a second variant of the process that is operated continuously and which serves to carry out the process according to the invention, is illustrated in Figure 2. In the first hydroformylation reactor 1 the olefinic mixture 2, the synthesis gas 3 as well as the catalyst 4 is introduced. The pressure of the hydroformylation mixture 5 is relieved, the gas used for pressure relief 6 is removed and the lower pressure hydroformylation mixture is released in the first catalyst separator system 7 of the catalyst 4, which optionally to be replaced by the introduction of fresh catalyst, is recirculated to the first hydroformylator reactor 1. The hydroformilator mixture 8 released from the catalyst, it is conducted to the first selective hydrogenator system 9 in which the aldehydes are hydrogenated, as well as the acetals and the esters contained as by-products, and especially the formates of the alcohols, to generate alcohols. From the first hydrogenation mixture 10, in the first distillation 11, the low-boiling substances which consist mostly of unreacted isomeric olefins and are taken to the second hydroformylation reactor 13, where the gas is also introduced, are separated in the first distillation. of synthesis 14 and the catalyst 15. The hydroformylation mixture 17 from the second hydroformylation reactor 13 is again subjected to a pressure drop and the gas is withdrawn from the one used for the relief. The hydroformylation mixture 17, of relieved pressure, is released in the second catalyst separator system 19 of the catalyst 15, which, optionally after being replenished with fresh catalyst, is recycled to the second hydroformylation reactor 13, and this material is carried as a hydroformylation mixture 20 devoid of catalyst, to a second hydrogenating system 22, of a selective and comparatively small type. The second hydrogenation mixture 23 decomposes in the second comparatively small distillation 24 into low-boiling paraffin-rich substances 16, which are removed, and crude alcohol 25, which is brought to the first distillation 11 and which is distilled there in conjunction with the first hydrogenation mixture 10. The crude alcohol 21 is again treated in a subsequent distillation, not illustrated, to obtain crude alcohol. A fundamental distinction of the two methods consists in that, according to FIG. 1, only selective hydrogenation 9 is envisaged, in which the two hydroformylation mixtures devoid of catalysts 8 and 20 are hydrogenated, only with a distillation 11, in which the hydrogenated mixture 10, while according to Figure 2 the second hydroformylation mixture 20 is hydrogenated in a second selective hydrogenation and the hydrogenation mixture is separated in a second distillation 24. The variant according to Figure 2 is more expensive in terms of your investment, whenever you need certain devices, in any case comparatively small, as additional equipment. But in this system the olefin is used to a high degree, since the low-boiling substances 16, according to FIG. 2, are smaller in their amounts than those substances with a low boiling point 16 according to FIG. Figure 1 and which are also highly olefin-free while the low-boiling substances 16 according to Figure 1 still contain considerable amounts by way of olefins.

Hydroformylation The educts or outgoing products for hydroformylation are mixtures of monoolefins with 5 to 24 carbon atoms and with a double CC bond, in the final or middle position, such as 1- or 2-pentene, 2-methyl-l- butene, 1-, 2- or 3-hexene, the isomeric-type C6-olefin mixture obtained in the dimerization of propene (dipropene), 1-heptene, 2- or 3-methyl-1- hexene, 1-octene, the isomeric 8-carbon olefinic mixture (dibutene), which is obtained in the dimerization of butenes, 1-heptene, 1-nonene, 2- or 3-methyl-1-octene, the isomeric 9-atom olefinic mixture (tripropene) which is obtained in the trimerization of 1-propene, 1-, 2- or 3-decene, 2-ethyl-1-octene, 1-dodecene, the olefinic mixture and isomeric with 2 carbon atoms (tetrapropene or tributene) that is obtained in the tetramerization of propene or in the trimerization of butenes, 1-tetradecene, 1- or 2-hexadecene, the olefinic groups with 16 carbon atoms (tetrabutene) that are obtained in the tetramerization of butenes as well as those olefins mixtures elaborated by means of a co-oligomerization of olefins with different numbers of carbon atoms (preferably from 2 to 4), possibly after a distillative separation in fractions with an equal or similar number of carbon atoms. Such educts or products Preferred projections are olefinic mixtures with 8, 9, 12 or 16 carbon atoms. The invention does not reside in the modality or in the conditions of the hydroformylation that is carried out in the two stages. Rather, the olefins are hydroformylated in a manner known per se. Accordingly, rhodium is used, or preferably in both stages, with cobalt catalysts and with certain additions stabilizing the complex or without them, as in the case of organic phosphines or phosphites. Temperatures and pressures can vary widely, according to the catalyst and the olefins mixture. In view of the fact that olefins which are more reactive react in the first stage, more vigorous reaction conditions are established in the second hydroformylation in terms of temperature, amount of catalyst and the like. For a given olefinic mixture, optimum conditions can be established for both stages of hydroformylation through tests, which is a little difficult intervention. A description of the hydroformylation of olefins is found, for example, in J. Falbe. New Syntheses with Carbon Monoxide, Springer Editorial, Heidelberg New York, 1980, pages 99ff, as well as with Kirk-Othmer, Encyclopedia of Chemical Technology, Volume 17, 4th edition, John Wiley & Sons, pages 902-919 (1996).

In general terms, hydroformylation is carried out in the first stage in such a way that 50% to 90% and preferably 60% to 85% of the olefinic mixture charged is converted. Of course, hydroformylation reactors and other devices must be arranged accordingly. The degree of conversion of the olefins, in the first stage of hydroformylation, is delimited at its desired value, effectively changing the reaction conditions of the hydroformylation. By choosing lower reaction temperatures or catalyst concentrations and shorter residence times, the conversion of the olefins present in the reactor can be reduced. The degree of conversion of the olefins in the first reactor is determined on the basis of the amount and composition of the fresh olefinic mixture 2 and also according to the amount and composition of the hydroformylation mixture 5. The total degree of the conversion is It shall be established on the basis of the quantity and composition of the fresh olefinic mixture 2 and according to the quantity and composition of the substances extracted with the lowest boiling point (16, according to both figures). For the determination of the olefin contents within the different streams of substances, the gas chromatography analysis can be applied.

Separation of the catalyst The reaction mixtures of the hydroformylation, as mentioned above, are released, in the first instance of the catalyst, from new beads in a manner known per se. When a cobalt catalyst has been used, the extraction can be carried out by pressure relief, separation of the aqueous catalyst phase, oxidation of the cobalt carbonyl compounds left behind in the hydroformylation mixture with air or oxygen and washing of the compounds Generated cobalt with water or with an aqueous acid. Methods for de-cobaltation are well known, see for example B. Falbe, cited above, 164, 165 (BASF-Process), Kirk-Othmer, see above, as well as in European Patent 850 905 Al. When a rhodium compound it has served as a catalyst for hydroformylation, it can be separated by thin-film evaporation as a distillation residue of the hydroformylation mixture. When the preferred cobalt catalysts have been used, the reaction mixtures released from the catalyst, the first hydroformylation stage, and according to the degree of conversion, contain in general terms from 8% to 45% by weight and in most the cases of 15% to 35% by weight of substances with a low boiling point and that is to say that they will have a lower boiling point than that of the aldehydes, mainly olefins, and in addition the corresponding saturated hydrocarbons as well as water and methanol: likewise 30 to 80% by weight of aldehydes, 5 to 30% by weight of alcohols up to 10% by weight of alcohol formates and 0.5 to 5% by weight of substances of high boiling point, that is to say those substances that have a boiling point higher than alcohols. In the reaction mixtures of the second hydroforming stage, there are generally 10 to 40% by weight, in most cases 15% to 30% by weight, of materials with a low boiling point, among which they find less olefins and many saturated hydrocarbons, as well as water and methanol, and in addition 30% to 70% by weight of aldehydes, 5% to 40% by weight of alcohols, up to 10% by weight of formates of these alcohols and 3% to 12% by weight of substances of high boiling point, ie substances having a boiling point higher than that of alcohols. When rhodium catalysts are used, the reaction mixtures clearly contain less paraffins and formates. Selective hydrosesination Selective hydrogenation of reaction mixtures efficiently released from the catalyst, coming from The two hydroformylation steps is a fundamental characteristic of the process according to the invention. The aldehydes and certain accompanying substances are hydrogenated, among which the acetals of the aldehydes and esters of alcohols and among them especially the formates, to generate the desired alcohols. In this case the unreacted olefins are not hydrogenated or practically not hydrogenated so that high yields are achieved as regards the olefinic mixtures used. An amount less than 5% of the olefins used is lost by hydrogenation, to the saturated hydrocarbons. A selective hydrogenation of the hydroformylation mixtures is a subject of the simultaneously pending patent application 198 42 370.5 (own reference "O.Z. 5356"). The reaction mixtures of the hydroformylation are then hydrogenated by hydrogen at increased temperature and pressure with the carrier catalyst which contains copper, nickel and chromium as active components. Preferred catalysts of this class are those carrier catalysts which, as active components, contain copper and nickel in the concentration of, in each case, 0.3% to 15% by weight of chromium in a concentration of 0.05% to 3.5% by weight, as well as a alkali metal component in a concentration of 0.01% to 1.6% by weight. The latter is contained in the material in an advantageous proportion of 0.02% to 1.2% by weight, related in each case to the carrier catalyst. Another advantageous carrier catalyst contains copper, nickel and chromium in the indicated amounts but does not contain any alkali metal component. Carriers or suitable support vehicles are particularly silicon dioxide and aluminum oxide. The indications on the quantities refer to the catalyst prepared as will be described below, and which has not yet been reduced. In the hydrogenation, the aldehydes in the reaction mixtures of both hydroformylation stages are hydrogenated in each case with conversion percentages of more than 98% at a selectivity of more than 99% only in one of the two hydrogenation steps, to thereby produce the corresponding alcohols. The esters and the acetals also become the desired alcohols. The starting olefins contained in the mixture remain surprisingly largely unchanged although the preferred carrier catalysts are hydrogenated practically in quantitative form, under comparable conditions, including the olefinic double bond within 2-ethylhex-2-enal (European EP memory 0 326 674 A2). Hydrogenation can be carried out in the range of low pressures of less than 30 bars and with high yields in space and time. The mentioned components of the catalyst can be homogeneously distributed in the pores of a carrier material or they can also be enriched in their marginal zones. In the first situation an aqueous solution is formulated which contains the components in the form of metal salts and whose volume corresponds approximately to 0.8 part of the volume in pores of the carrier material. As salts of copper, nickel and chromium, as precursors of the catalyst, those that during the heating process are converted into oxides, such as nitrates and acetates, are advantageously used. When the catalyst must contain an alkali metal component, the latter can be introduced together with the chromium in the form of chromate or alkali dichromate, especially as chromate or sodium dichromate. The concentration of the metal salts in the solution depends on the desired concentration of each component within the finished catalyst. The metallic salt solution is then sprayed onto the carrier material, present inside a dragee-generating drum, not preheated, and enters its pores. The catalyst is then subjected to drying. When it is desired to have a catalyst with components that are enriched in the marginal zones of a porous carrier material or more or less devoid of pores, the solution of the metal salt can be sprayed onto the previously heated material in order to continue heating the carrier material in the course of the spraying so that the water will evaporate and the catalyst components are fixed essentially on the surface of the carrier material. After the application of the catalyst components, the catalysts of the two mentioned types are calcined, that is to say, according to the catalyst precursor, they are heated to temperatures of 200 to 400 ° C, whereby the catalyst precursors are converted to their state of oxide. The catalyst is then reduced with hydrogen at the mentioned hydrogenation temperatures. The reduction can be carried out immediately after processing the catalyst or effectively only in the hydrogenation reactor. The catalysts are advantageously used in a form in which they offer low resistance to current, for example in the form of granules, pellets or spheres or molded bodies, such as tablets, cylinders or rings. They are activated efficiently before use, by heating in a stream of hydrogen, for example at the mentioned hydrogenation temperatures, provided they have not been reduced in the reactor.

The hydrogenation can be carried out continuously or intermittently and can be carried out in the gas phase as well as the liquid phase. Preference is given to hydrogenation in the liquid phase since the process in the gas phase due to the necessary circulation of large volumes of gas requires a high energy consumption. Furthermore, it can be said that the evaporation of the aldehydes when the number of carbon atoms grows requires more and more energy and therefore the load of products leaving or "educts" of the reduction gas decreases so that a gas phase process in the case of aldehydes with a carbon atom number greater than about 8 will make a general process of this type less feasible or industrially profitable. For the hydrogenation in the liquid phase, different variants of the process can be selected. It can be carried out in an adiabatic way or in a practically isothermal way, that is to say with an increase of temperature of less than 10 ° C, in a stage or in two stages. In the latter case, both reactors can be operated, which effectively will be tubular reactors, in an adiabatic or practically isothermal manner or one reactor can be operated in an adiabatic manner and the other in a practically isothermal manner. There is also the possibility of hydrogenate the hydroformylation mixtures in a straight system or product recirculation. The reactors can be operated as current reactors with comitant with their trickle flow or preferably with high liquid loads ("pulse flow"). For the sake of a high performance in space and time, the reactors are operated preferably with high liquid charges of 5 to 10 m3 and especially of 15 to 50 m3 per m2 of cross section of the empty reactor and per hour. If a reactor is operated in an isothermal manner and in a straight system, then the specific catalyst load (LHSV) can assume values between 0.1 and 10 h "1, preferably between 0.5 and 5 h" 1. The hydrogenation in liquid phase is generally carried out under a general pressure of 5 to 10 bar, especially between 15 and 25 bar. The hydrogenation in the gas phase can also be carried out under lower pressures, with correspondingly high gas volumes. The reaction temperatures are in the case of hydrogenations in liquid or gas phase, generally between 120 ° C and 220 ° C, especially between 140 and 180 ° C. Separation of the hydrosentation mixtures by means of a distillation After the hydrogenation is carried out, the reaction mixtures are elaborated in a higher level in a per se known, carrying out a distillation. Low-boiling substances, which mainly contain olefins and also saturated hydrocarbons, are separated as overhead products. According to FIG. 1, the low-boiling substances coming from the two hydroformylation steps constitute the outgoing product, ie the "reactant" for the second hydroformylation step. In this variant of the process, a part of these low-boiling substances is selectively removed in order to maintain the concentration of the saturated hydrocarbons created by hydrogenation of the olefins in the hydroformylation stages at an acceptable level of 60%. at most. In the process variant according to FIG. 2, all low-boiling substances are fed from the first distillation to the second hydroforming stage and the saturated hydrocarbons are extracted as a comparatively small fraction of low-boiling substances. , from the second distillation. The distillation of the hydrogenation mixtures is generally carried out at a reduced pressure, for example under an absolute pressure of 400 to 900 mbar. The crude alcohol, which is produced in the distillation as a product in the sump 2, can be processed at a higher level in the manner usual by distillation in pure alcohol. The following examples are intended to continue to illustrate the invention and should not limit its scope as described in the claims. Example 1 (comparison example) Nonanoles by hydroformylation in a single step of Di-n-butene. In a high-pressure autoclave with a capacity of 5 liters, which had been equipped with a stirrer and an electric heating system, 2000 g of Di-n-butene was charged (composition as mentioned in Table 1, column 2) in the presence of a cobalt catalyst, to undergo hydroformylation at 185 ° C, the synthesis gas pressure remaining constant at 280 bar. The synthesis gas contained 50% by volume of CO and 50% by volume of H2 For the preparation of cobalt hydride carbonyls that served as a catalyst, such as CHo (CO) 4, a catalyst solution was used as catalyst precursor Aqueous cobalt acetate with 1% by weight of Co. The cobalt acetate solution was treated with stirring during 7 hours at 170 ° C and under 280 bars with synthesis gas. After cooling to room temperature and relieving pressure, the cobalt carbonyls formed by extraction with Di-n-butene were passed into their organic phase. After separating the aqueous phase was hydroformilized the Di-n-butene charged with cobalt carbonyls, with a content of 0.021% by weight of Co (calculated as metal) under the reaction conditions mentioned above, for a time of 3 hours. After cooling to room temperature the reaction mixture was emptied, with its pressure relieved, from the autoclave, and by treatment with 5% acetic acid and air, at 80 ° C, it was released from the cobalt catalyst. 2487 g of a descoballated hydroformilator mixture were obtained which was analyzed by gas chromatography. The results are shown in Table 2, column 2. According to the above, a conversion of Di-n-butene of 92.3% and with a selectivity of valuable product of 87.9% was achieved, which corresponds to a yield of valuable product of 81.1% with respect to the Di-n-butene used. Valuable or useful products were aldehydes with 9 carbon atoms, alcohols with 9 carbon atoms and (Iso) nonyl formates. Example 2 Nonanoles by hydroformylation in 2 stages - Ia stage. In a high pressure autoclave with a capacity of 5 liters, which was equipped with a stirrer and an electric heater, 2000 g of Di-n-butene were hydroformylated (composition as mentioned in Table 1, column 2) in the presence of a cobalt catalyst, at 170 ° C, and under a synthesis gas pressure maintained at a constant level of 280 bar. The synthesis gas again contained 50% by volume of Co and 50% by H2. The cobalt catalyst was made as indicated in Example 1 and transformed into Di-n-butene. The concentration of the catalyst was 0.019% by weight of Co, with respect to Di-n-butene. Di-n-butene loaded with cobalt carbonyls was hydroformylated under the reaction conditions mentioned above for a period of 2 hours. The hydroformylation mixture was released from the cobalt catalyst, in the manner indicated in Example 1. This preparation by hydroformylation was repeated 3 times under the same conditions. The hydroformylation mixtures were pooled once the cobalt catalyst was removed. 9412 g of reaction mixture were obtained which, according to the gas chromatography analysis, had the composition indicated in Table 2, column 3. Accordingly, a conversion of Di-n-butene of 67.6% was achieved with a selectivity of valuable or useful product of 94.5%, which corresponds to a useful product yield of 63.9% in relation to the di-n-butene used. As valuable or useful products the aldehydes with 9 carbon atoms, the alcohols with 9 carbon atoms and the (Iso) nonylformiates. Example 3 Nonanoles by hydroformylation in 2 steps -2st stage An amount of 7500 g of the reaction mixture from Example 2 was selectively hydrogenated under olefins, to generate the useful product of alcohol with 9 carbon atoms. The hydrogenation was carried out intermittently in an autoclave with a capacity of 20 liters at "175 ° C and under a H2 pressure of 20 bar in liquid phase, in the presence of a carrier catalyst with 12.1% by weight of Cu, 3.0% by weight. weight of Ni and 2.5% by weight of Cr over aluminum oxide as the carrier material. Then, from the hydrogenation mixture, unreacted olefins were removed by distillation as low-boiling substances from the useful products and those substances with a higher boiling point. The fraction of the low-boiling substances contained, according to the analysis of gas chromatography, in addition to 98.5% by weight of hydrocarbons, including 87.9% by weight of olefins with 8 carbon atoms, about 1.5% by weight of hydrocarbons. methanol, which had been generated by hydrogenation (Iso) nonylformiates. The isomeric distribution of the isomers within the mixture of the isomers with 8 carbon atoms has been mentioned in Table 1, column 3. Compared with fresh Di-n-butene with 23% by weight of dimethylhexenes contained this mixture of 8 carbon atoms with 44% by weight of dimethylhexenes considerably larger quantities by way of these isomers with 8 carbon atoms which are slower to react. An amount of 2000 g of this mixture of olefinic isomers with 8 carbon atoms containing 10.6% by weight of paraffins with 8 carbon atoms and which had been enriched with dimethylhexenes was hydroformylated in an autoclave with a capacity of 5 liters at 185 °. C and under a synthesis gas pressure of 280 bar in the presence of a cobalt catalyst, in the manner described in Example 1. Again a synthesis gas with 50% by volume of Co and 50% was used. in volume of H2. With a cobalt content of 0.031% by weight, with respect to the mixture of olefins with 8 carbon atoms, this mixture was hydroformylated for a period of 3 hours and remained constant at the pressure of the synthesis gas. The hydroformylation mixture was relieved, in terms of its pressure, and released from the cobalt catalyst, as described in Example 1. 2438 g of a descoballated hydroformilator mixture were obtained whose composition has been reproduced in the Table 2, column 4, established by analysis in the form of gas chromatography. According to the above, a conversion of olefins with 8 carbon atoms of 91.3% with a selectivity of useful product of 83.0% was achieved, which corresponds to a yield in useful product in 75.8% with respect to the Di-n-butene used. Useful products were aldehydes with 9 carbon atoms, alcohols with 9 carbon atoms and (Iso) nonylformates. When Example 2 is collected as the first hydroformylation stage and Example 3 as the second hydroformylation stage according to the process according to the present invention, then based on the two steps, a total conversion of olefins of 97.1% was achieved with a selectivity of useful product of 91.5%, which corresponds to a total useful product yield of 88.8%, with respect to the olefinic mixture used. In comparison with the hydroformylation in a single step according to Example 1, an increase in the useful product yield of the order of 8 percentage points is therefore presented.

Table 1 Distribution of the isomers with 8 carbon atoms in the used mixture of olefins Table 2 Composition of hydroforming mixes

Claims (20)

1. CLAIMS 1. A process for the preparation of higher oxo-alcohols from mixtures of isomeric olefins containing 5 to 24 carbon atoms by hydroformylation in two steps in the presence of a cobalt or rhodium catalyst at increased temperature and pressure , characterized in that the reaction mixture from the first hydroformylation stage is selectively hydrogenated, this hydrogenation mixture is separated by a distillation in crude alcohol and in substances of a low boiling point which mainly consists of olefins, this latter part being conducted the second hydroformylation stage, again the reaction mixture of the second hydroformylation stage is selectively hydrogenated, the hydrogenation mixture is separated by distillation in crude alcohol and low-boiling substances, the crude alcohol is elaborated at a higher level through a distillation to obtain pure alcohol and at least a part of Substances with low boiling point are removed in order to extract saturated hydrocarbons.
2. 2. The process according to claim 1, characterized in that the reaction mixtures are released, with their pressure relieved, from the two hydroformylation stages, from the hydroformylation catalyst, before effect the selective hydrogenation.
3. 3. The process according to claim 1 or 2, characterized in that mixtures of olefins with 8, 9, 12 or 16 carbon atoms are used as leaving products or "educts" to carry out hydroformylation.
4. 4. The process according to any of claims 1 to 3, characterized in that cobalt catalysts are used in the two hydroformylation stages.
5. The process according to any one of claims 1 to 4, characterized in that only selective hydrogenation is envisaged in which optionally decatalyzed reaction mixtures of the hydroformylation steps are subjected to selective hydrogenation and a single distillation is carried out in which it is separated the hydrogenation mixture.
6. 6. The process according to claim 5, characterized in that a part of those substances having a lower boiling point is removed from the distillation, with the purpose of extracting the paraffins.
7. The process according to any of claims 1 to 4, characterized in that the reaction mixture from the second hydroformylation step, optionally decatalyzed, is hydrogenated in a second selective hydrogenation and the hydrogenation mixture is separated. in a second distillation.
8. The process according to claim 7, characterized in that the lower boiling substances coming from the second distillation are removed to extract the paraffins.
9. The process according to any of claims 1 to 8, characterized in that the hydroformylation reaction mixtures are selectively hydrogenated at increased temperature and pressure by a carrier catalyst which, as active components, contains copper, nickel and chromium.
10. The process according to claim 9, characterized in that a carrier catalyst is used which, as active components, contains copper and nickel in concentrations of 0.3 to 15% by weight of chromium, in each case, in a concentration of 0.05% to 3.5% by weight. weight and an alkali metal component in a concentration of 0.01% to 1.6% by weight, related in each case to the carrier catalyst.
11. 11. The process according to claim 10, characterized in that the concentration of the alkali metal component is from 0.2% to 1.2% by weight.
12. 12. The process according to claim 10, characterized in that the carrier catalyst does not contain any alkali metal component.
13. 13. The process according to any of claims 9 to 12, characterized in that the carrier material of the catalyst is silicon dioxide or aluminum oxide.
14. The method according to any of claims 1 to 13, characterized in that the hydrogenation is carried out continuously or intermittently in the liquid phase.
15. 15. The process according to any of claims 1 to 14, characterized in that the hydrogenation is carried out in liquid phase under a total pressure of 5 to 30 bar.
16. 16. The method according to claim 15, characterized in that the total pressure is from 15 to 25 bars.
17. 17. The process according to any of claims 1 to 16, characterized in that the hydrogenation is carried out at 120 to 220 ° C.
18. 18. The method according to claim 17 characterized in that the temperature is from 140 to 180 ° C.
19. 19. The process according to any of claims 1 to 18, characterized in that the hydrogenation is carried out in liquid phase and with liquid loads of 5 to 100 m3 for each square meter of empty reactor cross section and per hour.
20. 20. The process according to claim 19, characterized in that the charge for liquid is from 15 to 50 m3 for each square meter cross section of the empty reactor and per hour.