Method for obtaining alcohol from aldehyde

Abstract

To provide a method capable of selectively controlling a composition of obtained alcohol.SOLUTION: There is provided a manufacturing method of saturated C- and C-alcohol, wherein n=4, 5 and 6, consisting of following processes. There is provided a manufacturing method of saturated C- and C-alcohol having a) a process for aldol condensation of isomer C-aldehyde to obtain a mixture of C- and α,β-unsaturated C-aldehyde, b) a process for hydrogenating the mixture obtained in the process a) by hydrogen to obtain a mixture of saturated C- and C-alcohol, and c) a process for separating the mixture, in which the separation process of the mixture of the C- and C-alcohol is conducted by at least one 2 column system or the like, and an isomer ratio of the resulting C-alcohol is adjusted by aldol condensation conducted in the process a).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing C n - and C 2n - alcohols, and for the separation of the C n - alcohol and the C 2n - alcohol, it is carried out by at least one two-column system or by at least one dividing wall column.

Background Art

[0002] Alcohols play an important role in the industry. They are often used as intermediates for producing lubricants, fats, plasticizers, pharmaceuticals, cosmetics and fragrances. Also, alcohols are used directly as solvents, antifreeze agents or fuel additives.

[0003] Plasticizers are used in large amounts to improve the thermoplastic properties of many industrially important products such as, for example, not only plastics but also paints, coating compositions and sealants. Important classes of plasticizers are, inter alia, ester plasticizers including phthalic acid esters, trimellitic acid esters, phosphate esters and the like. The alcohols used for producing ester plasticizers are generally called plasticizer alcohols. To produce ester plasticizers having good performance characteristics, plasticizer alcohols having about 5 to 12 carbon atoms are required.

[0004] For the discussion of phthalic acid esters in the plasticizer sector, the demand for novel phthalic acid ester-free plasticizers is increasing. However, in this case, it is important that each plasticizer necessarily meets narrow criteria regarding its properties according to the application. Examples here include the viscosity or volatility of the plasticizer. The control of the essential properties of the plasticizer depends, in this case, not on the esterification reaction typically used in the production of plasticizers, but rather on the raw materials used, in particular the alcohol used. Important factors here are, for example, the number of carbon atoms of the alcohol used or its isomer distribution. For this purpose, alcohols having, for example, 4, 5 or 6 carbon atoms are suitable. However, at the same time, it is also necessary to produce the described C8-, C10- and C12-alcohols.

[0005] One of the best-known methods for the corresponding alcohol (C n -alcohol) to generate is the hydroformylation reaction that converts an alkene to an aldehyde and then hydrogenates it. The exception here is the hydroformylation of propene and unbranched butenes. Here, the obtained aldehyde is usually subjected to a further reaction step, namely aldolization, to produce long-chain unsaturated aldehydes. These are then also hydrogenated, and the resulting long-chain alcohol (C 2n -alcohol) is mostly used in the production of phthalate-containing plasticizers.

[0006] For example, Patent Document 1 describes the production of an alcohol from an olefin by hydroformylation, aldol condensation, and further hydrogenation of the aldol condensation mixture.

[0007] Patent Document 2 describes the cross-aldol condensation of butanal and pentanal to obtain isomeric nonanols and decanols following hydrogenation.

[0008] Patent Document 3 describes the production of an alcohol by hydroformylation of an olefin, aldol condensation of a part of the aldehyde, and further hydrogenation reaction.

[0009] Patent Document 4 describes a method for producing a hydroformylation product of an olefin having at least 4 carbon atoms and then further treating it with an alcohol, particularly 2-propylheptanol.

[0010] The prior art methods have the drawback that the composition of the product, particularly the composition of the final alcohol, is determined by the reaction stream used, particularly the olefin used. However, it is impossible to specifically control the composition of the resulting alcohol by this method, particularly with respect to variations in the composition of the reactants.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0012] The problem that then arises is to control, on the one hand, the isomer distribution of the alcohol produced and, on the other hand, particularly the ratio of C 2n -alcohol to C n -alcohol. The object of the present invention is to provide a method that satisfies the above requirements and enables the composition of the resulting alcohol to be selectively controlled.

Means for Solving the Problems

[0013] The object of the present invention is C 2n -from a mixture with alcohol Cn - The separation of the alcohol is carried out, and saturated C n - And C 2n - The production method of alcohol is achieved.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0015] Therefore, the present invention includes the following steps; a) Aldol condensation of isomeric C n - Aldehydes (where n = 4, 5 and 6) to obtain a mixture of C n - And α,β-unsaturated C 2n - Aldehydes, with the proportion of the unbranched aldehyde being at least 20% by weight based on the C n - Aldehydes (where n = 4, 5 and 6) used, b) Hydrogenating the mixture of C n - And α,β-unsaturated C 2n - Aldehydes obtained in step a) with hydrogen to obtain a mixture of saturated C n - And C 2n - Alcohols, and c) Separating the mixture of the C n - And C 2n - Alcohols having the C n - And C 2nThe separation step of the mixture with alcohol is carried out by at least one two-column system or at least one dividing wall column, The obtained C n The isomer ratio of the alcohol is adjusted by the aldol condensation carried out in step a), The proportion of linear C n -alcohol is at least 2 mol% and less than 60 mol% with respect to the mixture of the isomer C n -alcohol, and a saturated C n -and C 2n -relates to a process for the production of alcohols (where n = 4, 5 and 6).

[0016] The process chain of the present invention can surprisingly be directly used for the production of plasticizers C n -and C 2n -enable the production of alcohols. In particular in this case, for example C n -the isomer distribution of the alcohol is considerable, so that the plasticizer has advantageous spectral properties after esterification and is such that it can be used without additional pretreatment in the anhydride esterification reaction or the transesterification reaction C n -It has been found that a plasticizer with a low water content of alcohol results. What is important in the present invention is to adjust the isomer ratio of the obtained C n -alcohol. Based on the present invention, this is, firstly, the aldol condensation carried out in step a), and secondly, C n -alcohol and C 2n -is affected by the separation control of alcohol. For example, the isomer ratio can be controlled by the selectivity factor of aldol condensation. Generally, the aldehydes used show different reaction rates in aldolization. For example, n-pentanal reacts significantly faster than 2-methylbutanal. Furthermore, the desired isomer ratio is the isomer C used in step a n-aldehyde (where n = 4, 5 and 6) can also be controlled by the composition of the stream. According to the present invention, the proportion of the unbranched aldehyde is at least 20% by weight based on the C n -aldehyde (where n = 4, 5 and 6). The above control requirements mean that the proportion of linear C n -alcohol in the alcohol mixture obtained according to the present invention is less than 60 mol%, and the minimum content of linear C n -alcohol in the mixture of isomeric C n -alcohol is more than at least 2 mol%, preferably more than at least 10 mol%, more preferably more than 20 mol%, more preferably more than 22.5 mol%, more preferably more than 25 mol%, still more preferably more than 27.5 mol%, still more preferably more than 30 mol%, and still more preferably more than 35 mol%.

[0017] C n To monitor the control of the isomer ratio of C

[0018] The basic sequence of the method according to the present invention is shown in FIG. 1. In the first step, isomeric C n -aldehyde (where n = 4, 5 and 6) is converted by aldol condensation to obtain a mixture of C n and α,β-unsaturated C 2n -aldehyde.

[0019] In principle, all C n -aldehydes (where n = 4, 5 and 6) known to those skilled in the art, in pure form or in mixture form, are suitable for use in the method according to the present invention. The basic prerequisite is that the C n-aldehyde (wherein n = 4, 5 and 6), the proportion of the unbranched aldehyde is at least 20% by weight.

[0020] In particular, in the process according to the invention, an aldehyde stream of the same chain length is used. The proportion of the unbranched aldehyde is C n -aldehyde (wherein n = 4, 5 and 6), at least 20% by weight, preferably at least 40% by weight. In particular, the proportion of the unbranched aldehyde is C n -aldehyde (wherein n = 4, 5 and 6), 40 to 95% by weight, and particularly preferably, the proportion of the unbranched aldehyde is 95 to 99.5% by weight.

[0021] On an industrial scale, many such aldehydes or mixtures thereof are obtained from the corresponding olefins by hydroformylation.

[0022] Therefore, in a preferred embodiment of the invention, the C n -aldehyde (wherein n = 4, 5 and 6) used in step a) is produced by hydroformylating an isomeric olefin having 3 to 5 carbon atoms and synthesis gas in the presence of a hydroformylation catalyst to produce the defined aldehyde. Suitable hydroformylation methods are known to those skilled in the art and are described, for example, in Hydroformylation Fundamentals, Processes and Applications in Organic Synthesis Volume 1 & 2 Edition 1, Franke, Borner, Willey VCH Verlag GmbH & Co.

[0023] Generally, the process is carried out using a rhodium or cobalt catalyst, with or without a complex stabilizing additive such as an organic phosphine or phosphite. The temperature and pressure may be varied within a wide range depending on the catalyst or the olefin. Descriptions of the hydroformylation of olefins can be found, for example, in J. Falbe, New Syntheses with Carbon Monoxide, Springer-Verlag, Heidelberg - New York, 1980, pages 99 ff. and in Kirk - Othmer, Encyclopedia of Chemical Technology, Volume 17, 4th Edition, John Wiley & Sons, pages 902 to 919 (1996).

[0024] The reaction mixture of the hydroformylation is preferably first removed from the catalyst before the aldol condensation according to step a) of the process according to the invention. When using a cobalt catalyst, this can be achieved by depressurizing, oxidizing the cobalt carbonyl compounds remaining in the hydroformylation mixture in the presence of water or an aqueous acid, and further removing the aqueous phase. The decobaltization process is well - known and can be found, for example, in J. Falbe, loc. cit., Kirk - Othmer, loc. cit., 164, 175, BASF - Verfahren.

[0025] When using a rhodium compound as the hydroformylation catalyst, it can be removed as a distillation residue, for example, by thin - film evaporation.

[0026] In a preferred embodiment of the present invention, the hydroformylation is carried out according to the method described in WO2017 / 080690.

[0027] In this case, in the hydroformylation, it contains rhodium as the central atom and further a ligand (1):

[0028]

Chemical formula

[0029] A catalyst system complexed therewith is used.

[0030] The IUPAC name of ligand (1) is 3,3'-di-tert-butyl-5,5'-dimethoxy-[1,1'-biphenyl]-2,2'-diyltetrakis(2,4-dimethylphenyl)bis(phosphite).

[0031] Hydroformylation is carried out especially at a temperature of 120 °C to 140 °C. The pressure is preferably 15×10 5 Pa to 25×10 5 Pa. In order to lengthen the operation time, hydroformylation is carried out in the presence of an organic amine of formula (2).

[0032] [Chemical formula]

[0033] (In the formula, Ra, Rb, Rc, Rd, Re and Rf represent the same or different hydrocarbon groups, and may be bonded to each other.)

[0034] The organic amine preferably contains at least one 2,2,6,6-tetramethylpiperidine unit. Specifically, the organic amine may be di-4-(2,2,6,6-tetramethylpiperidinyl)sebacate.

[0035] It is recommended to set the rhodium concentration in the first reaction mixture to 1 ppmw to 1000 ppmw. The ligand / rhodium ratio should be from 1:1 to 100:1, and in addition to the organophosphorus compound according to formula (1), no further ligand should be provided as part of the homogeneous catalyst system. In industrial operations, due to impurities, it is not possible to remove the formation of a complex with rhodium by organophosphorus compounds other than 3,3'-di-tert-butyl-5,5'-dimethoxy-[1,1'-biphenyl]-2,2'-diyltetrakis(2,4-dimethylphenyl) bis(phosphite) as part of the catalyst system. However, such impurities can be ignored at a specific ligand / rhodium ratio. This description relates only to ligand (1), and there is no need to intentionally provide further ligands.

[0036] Isomer C used in the process according to the invention n -aldehyde (where n = 4, 5 and 6) is, according to the invention, converted by aldol condensation, in particular in the presence of an aqueous sodium hydroxide solution, into a mixture with C n - and α,β-unsaturated C 2n -aldehyde. Suitable processes are known, for example, from DE19957522A1, DE102009045139A1, DE102009001594A1.

[0037] The aldol condensation is particularly preferably carried out in a tubular reactor having at least one mixing module in which the reactive aldehyde is dispersed in droplets with an average diameter (Sauter diameter) of 0.2 mm to 2 mm in a continuous catalyst phase (process liquid), which contains only an aqueous sodium hydroxide solution and the sodium salt of a carboxylic acid, the sodium content being 0.6 to 1.75% by mass and the pH being in the range of 12.5 to 13.5.

[0038] To produce the process liquid, an aqueous sodium hydroxide solution is used in the method according to the invention. The aqueous sodium hydroxide solution produces the process liquid together with the return liquid. The return liquid contains sodium salts of carboxylic acids, mainly pentanoic acid, like sodium hydroxide. The carboxylate is basically produced by the Cannizzaro reaction.

[0039] In the method according to the invention, the sodium content of the process liquid at the reactor inlet is 0.60 - 1.75% by mass, in particular 1.1 - 1.20% by mass. To adjust the sodium concentration of the process liquid, an aqueous sodium hydroxide solution is fed to the return liquid at a concentration exceeding 2.5% by mass. It is preferred to use an aqueous sodium hydroxide solution with a relatively high concentration to introduce a small amount of water into the reaction system. In the method according to the invention, it is preferred to use an aqueous sodium hydroxide solution in the concentration range of 5 - 30% by mass, for example 10% by mass.

[0040] The method according to the invention is carried out in a tubular reactor having at least one mixing module, preferably two or more mixing modules. In particular, the number of mixing modules is 1 - 30, especially 10 - 20.

[0041] The mixing module means a static mixer, i.e., a passive component that does not require direct specific energy.

[0042] The tubular reactor is preferably composed only of vertically arranged tubes. The flow through it can be from bottom to top or vice versa. Industrial reactors are also composed of a plurality of tubes arranged in parallel, which are connected to each other by U - shaped tubes.

[0043] The mixing module is preferably present at the reactor inlet. There are voids between the mixing modules. The volume ratio of the total volume of the reactor outside the mixing module is 20 - 80%, particularly 30 - 60%. The mixer modules may have equal or different distances from each other. The distance between the mixer modules preferably decreases in the flow direction. The distance between the mixing modules is 0.2 - 5 times, particularly 0.5 - 2 times the length of the mixing module, depending on the intended superficial velocity, the phase ratio of the reactant phase and the catalyst phase, the reaction progress, and the type of mixer.

[0044] The mixing module is composed of a static mixer or an arrangement of two or more, preferably two static mixers.

[0045] When the mixer module is composed of two identical static mixers, they are preferably arranged twisted around the longitudinal axis of the reactor, particularly twisted at an angle of 45° to 90°. The mixing elements are preferably arranged at a distance of two pipe diameters within the mixer module.

[0046] Also, the mixing module may be composed of static mixers of different designs. In the case of a mixer module composed of two static mixers, the first one preferably has a smaller hydraulic diameter than the second one. In this case, the first static mixer generates very small droplets, and the second static mixer, as a result of selecting a larger hydraulic diameter, prevents the coalescence of the droplet group.

[0047] The hydraulic diameter of the mixing elements of the mixer module preferably decreases in the flow direction.

[0048] The mixer modules may be the same or different within the reactor, i.e., they may have the same or different designs.

[0049] The mixing element used may be any static mixer capable of dispersing the organic phase in the catalyst phase into droplets having an average Sauter diameter in the range of 0.2 to 2.0 mm under the intended reaction conditions.

[0050] The static mixer used in the process according to the invention may be a mixing element suitable for the dispersion of two immiscible low-viscosity liquids, such as those commercially available. According to the present invention, C n The aldol condensation of C-aldehyde is carried out in a temperature range of 100 to 150 °C, more preferably in the range of 110 to 140 °C, particularly preferably in the range of 120 to 140 °C.

[0051] The reaction can be carried out isothermally, adiabatically or polytropically within the specified temperature range. For example, the temperature at the reactor inlet may be 120 °C, and further the temperature at the reactor outlet may be 140 °C.

[0052] The reaction pressure in the reactor is at least high enough so that both the process liquid and the organic substances (reactants and products) are present as liquid phases respectively. The pressure is in the range of 0.2 to 1.0 MPa, preferably in the range of 0.3 to 0.5 MPa.

[0053] In the process according to the present invention, the ratio [kg / kg] of the process liquid to the reactants at the reactor inlet is in the range of 5 to 40, particularly in the range of 10 to 15.

[0054] The average superficial velocity of the mixture of reactants and process liquid in the industrial reactor (assuming the flow rates of both phases are the same) is in the range of 0.5 to 4 m / s, particularly in the range of 1 to 2.5 m / s.

[0055] The average residence time of the reaction mixture in the reactor is 40 to 360 seconds, particularly 60 to 180 seconds.

[0056] In the process according to the present invention, the droplets of the organic phase dispersed in the process liquid when leaving the mixer module have an average Sauter diameter of 0.2 to 2 mm, particularly 0.6 to 1.3 mm.

[0057] The load factor ranges from 0.2 to 0.8.

[0058] The obtained aldehyde may optionally be treated before the hydrogenation according to step c).

[0059] One of the methods is to cool the reaction product and separate the organic phase from the liquid phase. The phase separation is preferably carried out in a temperature range of 60 to 130°C, more preferably in a range of 70 to 120°C, and particularly preferably in a range of 90 to 110°C. Depending on the selected temperature, the separation time is 3 to 10 minutes. At temperatures above 90°C, the separation time is within 8 minutes. The separation time is defined as the time until the phase of the valuable organic product is transparent and contains no heterogeneous water.

[0060] To separate the heavy aqueous phase from the light organic phase, a separator that promotes phase separation using only gravity may be used. Also, these so-called gravity separators may have an internal structure as a coalescence promotion means to improve the separation performance. The use of the internal structure promotes the coalescence process and the sedimentation process. As the coalescence aid, for example, plates, random packings, mesh packings or fiber bed separators can be used. The gravity separator can be configured as a horizontal vessel or an upright vessel.

[0061] As an alternative to the gravity separator, it is also possible to use a separator that operates according to the centrifugal principle for liquid-liquid separation. The heavy phase is separated by the centrifugal force in the rotating drum.

[0062] In the method of the present invention, it is preferable to use a gravity separator to separate the heavy aqueous phase, and it is preferable to use a gravity separator configured as a horizontal vessel having an internal structure.

[0063] A part of the separated liquid phase is discharged to remove the water of reaction, and the other part is recycled to the reactor. Along with the discharge stream, a part of the carboxylic acid formed as a by-product (as a sodium salt) and sodium hydroxide are also removed. This stream can be sent to a wastewater treatment plant. However, as described, for example, in DE 198 49 922 and DE 198 49 924, it is also possible to post-treat this stream and partially recycle it to the process.

[0064] If the organic phase contains, in addition to C n - and α,β-unsaturated C 2n - aldehydes, other by-products such as carboxylates, sodium hydroxide and dissolved water, a small amount of base and some carboxylates can be removed by washing with water. Fresh base can be made using the obtained water extract.

[0065] As already outlined above, the isomer ratio of the alcohols and others produced according to the invention is controlled by aldol condensation. In particular, according to the invention, the degree of conversion of the aldehyde used, and thus the C n The isomer composition of the aldehyde can be controlled by controlling the reaction temperature and the liquid concentration in the aldolization reaction. Controlling the residence time of the aldehyde used is an even more effective means of controlling the degree of conversion of these aldehydes. This can be achieved, for example, by changing the reaction space and / or by controlling the feed rate. Alternatively, or by interaction with the above influencing factors, the residence time and the aldehyde concentration may also be affected, and thus the degree of conversion can also be controlled by adding a suitable solvent to the feed stream.

[0066] The C n - and α,β-unsaturated C 2n - aldehydes thus obtained are hydrogenated with hydrogen according to step b) of the process according to the invention to give saturated C n - and C 2n- A mixture of alcohols is obtained. The hydrogenation is carried out in accordance with methods known per se, for example on a supported catalyst containing at least nickel and copper as active components, as is known from, for example, EP3037400, at a pressure of 15×10 5 Pa to 30×10 5 Pa and in a temperature range of 170 °C to 200 °C as well.

[0067] The hydrogenation catalyst preferably contains only a support material based on titanium dioxide, zirconium dioxide, aluminum oxide, silicon oxide or mixtures thereof, and at least one element selected from the group of hydrogenation-active metals, in particular copper, cobalt, nickel, chromium, is applied to this support material.

[0068] As the support precursor, aluminum oxide, aluminosilicate, silicon dioxide, titanium dioxide, zirconium dioxide can be used. A preferred support precursor is aluminum oxide, in particular γ-aluminum oxide. The catalyst may contain one or more hydrogenation-active metals. The catalyst according to the invention preferably contains metallic copper, chromium, nickel. The catalyst particularly preferably contains a combination of three metals, copper, chromium and nickel, as the hydrogenation-active metals.

[0069] The total content of the hydrogenation-active metals relative to the reduced catalyst is in the range of 1 to 40% by mass, particularly in the range of 5 to 25% by mass, calculated as the metal.

[0070] The catalyst according to the invention is preferably prepared in a form that causes low flow resistance during hydrogenation, for example in the form of tablets, cylinders, strand extrudates or rings. During the preparation process of the catalyst, the preliminary support material is generally brought into an appropriate form. Shaped preliminary support materials are also commercially available.

[0071] In the process according to the invention, the hydrogenation can be carried out continuously or batchwise on a finely divided or shaped catalyst suspended in a fixed bed. The product / reactant phase is mainly in the liquid state under the reaction conditions, and continuous hydrogenation on a catalyst arranged in a fixed bed is preferred.

[0072] When the hydrogenation is carried out continuously on a catalyst arranged in a fixed bed, it is preferred to convert the catalyst into an active form before the hydrogenation. This can be achieved by reducing the catalyst with a hydrogen-containing gas according to a temperature program. In this case, the reduction can optionally be carried out in the presence of a liquid phase passing over the catalyst, as described, for example, in DE 199 33 348.

[0073] The process according to the invention is carried out in a trickle phase or preferably in a liquid phase in a three-phase reactor in cocurrent, and the hydrogen is finely dispersed in the liquid reactant / product stream by a method known per se. For homogeneous liquid dispersion, improved removal of the reaction heat and high space-time yield, the reactor is preferably 1 m per cross-sectional area of the empty reactor 2 per hour and 15 - 120 m 3 and in particular 25 - 80 m 3 is operated at a high liquid filling level. When the reactor is operated isothermally and linearly, a specific liquid hourly space velocity (LHSV) can take values between 0.1 - 10 h -1 .

[0074] The process according to the invention is carried out using hydrogen in a pressure range of 5 - 100 bar, preferably 5 - 40 bar, particularly preferably 10 - 25 bar. The hydrogenation temperature is 120 - 220 °C, particularly 140 - 190 °C.

[0075] The hydrogen used for the hydrogenation may contain an inert gas such as methane or nitrogen. It is preferred to use hydrogen having a purity of more than 98%, particularly more than 99%.

[0076] Regarding the method according to the present invention, various method variations may be selected. This method can be carried out in one step or in multiple steps adiabatically or substantially isothermally, i.e., with a temperature increase of less than 10°C. In the latter case, all reactors, preferably tubular reactors, may be operated adiabatically or substantially isothermally, or one or more reactors may be operated adiabatically and other reactors may be operated substantially isothermally. It is also possible to hydrogenate a carbonyl compound or a mixture of carbonyl compounds in the presence of water in a straight path or by product recycle.

[0077] α,β-unsaturated C 2n In addition to the -aldehyde, hydrogenation also converts the unreacted C in aldolization n starting aldehyde to the corresponding saturated alcohol.

[0078] According to the present invention, the separation of the C n alcohol and the C 2n alcohol mixture is carried out after the hydrogenation by step c), and the separation of the C n -alcohol and the C 2n -alcohol is carried out by at least one two-column system or at least one dividing wall column.

[0079] In both cases, using a two-column system or a dividing wall column in sequence to obtain the saturated C n - and C 2n -alcohols as valuable products is essential in the present invention.

[0080] Various method variations are described in more detail below.

[0081] In one embodiment of the present invention, at least one two-column system is used. In the first column, during the course of the method, the formed alkane (mainly nonane in the case of butene) is the C n-Alcohol (e.g., 2-methylbutanol) and water are taken in via the top of the column. Phase separation occurs there, and then the organic phase is returned as reflux and supplied to the column again. By this azeotropic drying, the water content at the bottom of the column can be obtained to be less than 1000 ppm.

[0082] In the second column, C n Alcohol is taken in via the top of the column and thus separated from high boilers. By an appropriate operating mode of the column, the isomer composition of C 5 Alcohol can be further controlled.

[0083] Figure 2 shows the detailed sequence of separation of a mixture of C n and C 2n -alcohol by a two-column system subdivided into the following substeps.

[0084] I. Distillation separation (G) of the crude product stream of hydrogenation by step b) into a low-boiling stream (6) and a high-boiling stream (15). In this case, the low-boiling stream (6) contains, as the main product, the alcohol of the starting aldehyde and an additional substance or azeotropic mixture having a boiling point lower than the alcohol formed from α,β-unsaturated C 2n -aldehyde and heterogeneous water. The high-boiling stream (15) contains, as the main product, the alcohol formed from α,β-unsaturated C 2n -aldehyde and a high boiler or azeotropic mixture having a boiling point higher than C 2n -alcohol. II. Removal of heterogeneous water (7) from the distillate fraction (6) via the separator (F). III. Distillation separation (H) of the organic phase (8) from (F) into a low-boiling stream (9) and a high-boiling stream (12). The low-boiling stream (9) contains a substance or azeotropic mixture having a boiling point lower than the highest-boiling C n -alcohol and may contain heterogeneous water (11) after concentration. The high-boiling stream mainly contains C n -alcohol and a substance or azeotropic mixture having a boiling point higher than the highest-boiling C n -alcohol. IV. Removal of the heterogeneous water (11) by phase separation (E). The organic phase is recycled as the return flow (19) and re-supplied to the column (H). A part of the obtained organic phase (10) is taken out of the system. V. Distillation separation (I) of the high-boiling stream (12) into a low-boiling stream (4) and a high-boiling stream (14). The low-boiling stream (4) mainly contains C n -alcohol with the desired isomer distribution. The high-boiling stream (14) mainly contains substances or azeotropic mixtures having a boiling point higher than that of the highest-boiling C n -alcohol. VI. Distillation separation of the high-boiling stream (15) into a low-boiling stream (5) containing C n -alcohol and a high-boiling stream (18). The low-boiling stream (5) mainly contains C 2n -alcohol. The high-boiling stream (18) mainly contains substances or azeotropic mixtures having a boiling point higher than that of the highest-boiling C 2n -alcohol.

[0085] In any case, according to the composition of the product stream from the hydrogenation (step b) of the process according to the invention, the temperature profile used in the column is adjusted. For example, the product stream (3) can have the following composition:

[0086]

Table 1

[0087] In the case of this composition, column (G) is preferably operated at a top pressure of 0.2 bar (absolute) and a pressure drop of 0.1 bar, and a bottom temperature of 176 °C and a top temperature of 65 °C or a corresponding temperature is maintained. Column (H) is particularly operated at a bottom temperature of 137 °C and a top temperature of 94 °C or a corresponding temperature, at a top pressure of 1.05 bar (absolute) and a pressure drop of 0.03 bar. Column (I) is generally maintained at a bottom temperature of 178 °C and a top temperature of 134 °C or a corresponding temperature, at a top pressure of 1.08 bar (absolute) and a pressure difference of 0.03 bar.

[0088] Column (J) is operated at a bottom temperature of 175 °C and a top temperature of 158 °C or a corresponding temperature, at a pressure of 0.15 bar (absolute) and a pressure difference of 0.006 bar. The defined temperature profile is to be considered as an example. Further configurations are included in the invention, particularly in relation to various feed compositions.

[0089] In a further equally preferred embodiment of the invention, at least one dividing wall column is used. In a dividing wall column, the separation operations described for a two-column system can be combined into one column. An example of an alkane / 2-methylbutanol / water mixture is also obtained via the top of the column, subjected to a similar phase separation, and the organic phase is returned to the column as reflux. By means of a side draw in the dividing wall region, the C n -alcohol fulfilling the specifications is removed. The isomer ratio of the C n -alcohol in the side draw can be controlled within a specific range by reducing the distillate of the organic phase and the alcohol ratio at the bottom of the column. Figure 3 shows the sequence when using a dividing wall column (K) to separate the low-boiling stream (6).

[0090] In this context, columns H and I shown in Figure 2 are combined to form a dividing wall column (K) (see Figure 3). The dividing wall column (K) is maintained at a top pressure of 1.05 bar (absolute) and a pressure drop of 0.06 bar, a bottom temperature of 180 °C, a top temperature of 118 °C and a product temperature of 134 °C or a corresponding temperature.

[0091] Figure 4 shows a further preferred embodiment, in which the separation of the crude product stream from hydrogenation b) is also achieved by means of a dividing wall column. In this case, the C 2n -alcohol is removed by means of a side draw in the dividing wall region.

[0092] The process according to the invention is suitable in a process advantageous for the production of C n - and C 2n -alcohols from aldehydes and in the case of an upstream hydroformylation from olefins.

[0093] Isomers C for n = 4, 5 and 6 n -Aldehydes are particularly preferred. As already mentioned above, such aldehydes can be obtained by hydroformylation of the corresponding isomeric olefins. In the latter case, these are in particular olefins having 3 to 5 carbon atoms, namely propene, butene and pentene, and (in the case of butene and pentene) the respective positional isomers are included using specific names. The isomeric olefins are particularly preferably butene. In the latter case, these are converted into pentanol mixtures and decanol mixtures by the process according to the invention.

[0094] Regarding plasticizer synthesis, the isomer distribution of the pentanol mixture is particularly interesting. By way of example and preferred embodiment, the obtained pentanol mixture preferably contains less than 60 mol% of n-pentanol. The minimum content of n-pentanol in the mixture of isomeric pentanols is preferably at least 2 mol%, preferably at least 10 mol%, more preferably more than 20 mol%, even more preferably more than 22.5 mol%, further more than 25 mol%, even more preferably more than 27.5 mol%, more than 30 mol%, further more than 35 mol%. In addition to the straight-chain n-pentyl group, pentanols containing branched-chain pentyl groups are particularly preferred. The branched-chain pentyl group is preferably a methylbutyl group. Therefore, a pentanol mixture consisting of at least 50 mol%, preferably at least 60 mol%, more preferably at least 70 mol%, even more preferably at least 80 mol%, even more preferably at least 90 mol%, particularly at least 95 mol% of methylbutyl groups is preferred.

[0095] It is advantageous when the branched-chain isomeric pentyl group has a majority of 2-methylbutyl groups. Thus, in a preferred embodiment, at least 50 mol%, preferably at least 60 mol%, more preferably at least 70 mol%, still more preferably at least 80 mol%, particularly preferably at least 90 mol%, especially at least 95 mol% of the branched-chain isomeric pentyl groups are 2-methylbutyl groups. A preferred pentanol mixture preferably contains 20 to 95 mol%, preferably 30 to 85 mol%, particularly 40 to 75 mol% of 2-methylbutyl groups, based on all pentyl groups present.

[0096] In a particularly preferred embodiment, the pentanol mixture contains at least 75 mol%, more preferably at least 90 mol%, especially at least 95 mol% of pentanol, preferably consisting solely of 2-methylbutyl groups and / or linear pentyl groups, and the molar ratio of 2-methylbutyl groups to linear pentyl groups in this pentanol mixture is preferably from 99:1 to 40:60, particularly from 70:30 to 40:60.

[0097] The desired product properties, in particular the above isomer distribution, are determined by the parameters described in each of steps a), b) and c), in particular the aqueous sodium hydroxide solution used in the aldolization and the temperature defined therein (see step a), and the C by means of the two-column system or dividing wall system according to the invention defined in step c) n and C 2n - separation of the mixture of alcohols is adjusted by the parameters for carrying out.

[0098] Without further elaboration, it is believed that one of ordinary skill in the art can, using the preceding description, utilize the present invention to its fullest extent. The preferred embodiments and examples are, therefore, to be construed as merely illustrative of the disclosure and not in a limiting sense. The present invention will be described in more detail below by way of examples. Alternative embodiments of the invention can be obtained in a similar manner.

[0099] Examples To conduct the examples and determine each parameter, C where n = 5 n / C 2n Based on the system, the following basic assumptions were used.

[0100] The conversion degrees Xi1 and Xi2 were calculated by the following calculation methods:

[0101]

Chemical formula

[0102] The ratio of n-pentanal to C5-aldehyde in the product (Sn1) was calculated by the following calculation method:

[0103]

Chemical formula

[0104] The ratio of 2-propylheptanal to unsaturated C10-aldehyde in the product (Sn2) was calculated by the following calculation method:

[0105]

Chemical formula

[0106] The chemical composition in the examples was measured by gas chromatography. For this purpose, an Agilent 7890A gas chromatograph was used together with a flame ionization detector (FID). The column used was HP-5 (5% phenylmethylsiloxane) at 325 °C, 30 m × 320 μm × 0.25 μm. The following temperature program was applied to the analysis: 2 minutes at 50 °C, then 150 °C at 10 °C / min, then including a holding phase of 10 minutes, up to 250 °C at 40 °C / min. Injection volume 0.5 μl. Nitrogen carrier gas at an injector temperature of 250 °C, flow rate 105 ml / min and split ratio of 50:1.

[0107] Example 1: Aldolization of n-pentanal including condensation to α,β-unsaturated C10 aldehyde in a stirred reactor: The α,β-unsaturated C10 aldehyde was prepared in a stirred reactor. This reactor was in the shape of an extraction column with a volume of 2.1 liters. The reactor was divided into 10 mixing chambers. Each of these mixing chambers was equipped with a four-blade stirrer attached to a common stirrer shaft. The catalyst phase was passed through the reactor by a circuit pump in the circuit. A 2% aqueous sodium hydroxide solution was used as the catalyst phase. The catalyst circulation was 80 L / hour for all experiments. The reactant contained 98.3% by mass of n-pentanal, and the remaining fraction up to 100% consisted of secondary components. The reactant was continuously fed into the catalyst circuit at 8 L / hour immediately before the reactor inlet. The two-phase mixture obtained at the reactor outlet was separated into an organic product phase and a catalyst phase in a phase separation vessel. This system was operated under a nitrogen atmosphere at a pressure of 4 bar, and the following results were measured after 3 hours of steady operation.

[0108] [Table 2]

[0109] Example 2: Aldolization of n-pentanal and 2-methylbutanal including condensation to α,β-unsaturated C10 aldehyde in a flow tube: The α,β-unsaturated C10 aldehyde was prepared in a DN15 tube with an inner diameter of 17.3 mm and a length of 3 meters. The volume of this tube was 6.8 L. Approximately 50% of the total volume was filled with a static mixer with a flow path diameter of 2 mm. The mixing elements were formed from serrated lamellae that formed open cross channels. The channels were arranged in the tube at a mixing distance of 1, shifted 90 degrees from each other. Using a pump, a continuous circulation of the catalyst phase at 80 L / hour was established through this tube. A 2.1% aqueous sodium hydroxide solution was used as the catalyst phase. The reactants contained 94.4% by mass of n-pentanal and 5.0% by mass of 2-methylbutanal, with the remaining percentage up to 100% consisting of secondary components. Immediately before the start of the static mixer, the reactants were continuously fed into the catalyst circuit at 8 L / hour. The two-phase mixture obtained at the reactor outlet was separated into an organic product phase and a catalyst phase in a phase separation vessel. This system was operated under a nitrogen atmosphere at a pressure of 4 bar, and the following results were measured after 3 hours of steady operation.

[0110]

Table 3

[0111] Example 3: Aldolization of n-pentanal and 2-methylbutanal, including condensation to α,β-unsaturated C10 aldehyde in a flow tube The α,β-unsaturated C10 aldehyde was prepared in a DN15 tube with an inner diameter of 17.3 mm and a length of 4 meters. The volume of this tube was 9.1 L. Approximately 50% of the total volume was filled with a static mixer having a flow path diameter of 2 mm. The mixing elements were formed from serrated lamellae that form open cross channels. The channels were arranged in the tube at a mixing distance of 1 and shifted 90° from each other. Using a pump, continuous circulation of the catalyst phase at 80 L / hour was established through this tube. A 2.1% aqueous sodium hydroxide solution was used as the catalyst phase. The reactants contained 93.7% by mass of n-pentanal and 5.2% by mass of 2-methylbutanal, with the remaining percentage up to 100% consisting of secondary components. Immediately before the start of the static mixer, the reactants were continuously fed into the catalyst circuit. In this example, the amount of reactants was varied. The two-phase mixture obtained at the reactor outlet was separated into an organic product phase and a catalyst phase in a phase separation vessel. This system was operated under a nitrogen atmosphere at a pressure of 4 bar, and the following results were measured after 4 hours of steady operation.

[0112]

Table 4

[0113] Example 4 The product streams obtained at 110 °C and 130 °C in Example 2 were hydrogenated. For the hydrogenation, a circulation system similar to that of DE102009045718A1 of Example 1 was used. Similarly, as strand extrudates with a diameter of 1.5 mm and a length of 3 - 5 mm, Al 2 O 3 On this, 105 g of a catalyst consisting of Cu (6 mass%) / Ni (3.1 mass%) / Cr (0.6 mass%) was used. The reaction conditions were 180 °C and an absolute pressure of 25 bar. The reactant feed rate was 100 mL / h at a circulation rate of 40 L / h and an off-gas rate of 60 Nl / h.

[0114] [Table 5]

[0115] Example 5 For the purification evaluation of the product stream from hydrogenation, a simulation study was carried out. The product stream obtained in Example 4 was separated into individual fractions according to Figure 2. For this purpose, Aspen Plus V7.3 using the PSRK (Predictive Soave-Redlich-Kwong) method was used. The column was simulated as a Radfrac model and the column was configured so that product separation at a purity of approximately 99.9% was possible. Four columns with different specifications were prepared to achieve the product quality.

[0116] [Table 6]

[0117] By adding water (to the feedstock of Column I), the separation of low-boiling substances is facilitated. Therefore, water does not accumulate in the column and an aqueous phase is formed; water is removed to the decanter at the top of each column.

[0118] [Table 7]

[0119] Example 6 As an alternative to the separation using four columns, the separation may be carried out using a dividing wall column (similarly simulated using Aspen Plus V7.3, PSRK and Radfrac). For example, if columns 2 and 3 are replaced with a 31-stage Shi dividing wall column, the alcohol of the starting aldehyde may be taken out as the middle fraction. In this case, the dividing wall extends across the 14th of 31 plates. The product is discharged at the 15th stage. The vapor stream hitting the dividing wall from below is equally supplied to the two column segments, while 75% of the liquid stream is sent to the product side and 25% to the feed side. When the overhead product of column 1 is sent to the dividing wall column, the following product distribution occurs.

[0120] [Table 8]

[0121] The results show that the amount of alcohol and the isomer distribution can be specifically controlled by changing the isomer composition of the aldehyde used, by affecting mass transfer, by the temperature and residence time of the reactants in the aldolization reaction step, and by subsequent hydrogenation and precision distillation of the alcohol from the starting aldehyde and the alcohol from the α,β-unsaturated aldehyde.

[0122] List of reference symbols 1. Hydroformylation product 2. Aldol condensate 3. Hydrogenation product (e.g., when n = 5, mainly water, butane, butene, C 5 -aldehyde, 2-methylbutanol, pentanol, nonane, α,β-unsaturated C 10 -aldehyde, C 10 -aldehyde, α,β-unsaturated C 10 -alcohol, C 10- Alcohol, C10+ - oligomers having more than 10 carbon atoms) 4.C n - Alcohol (for example, when n = 5, mainly 2 - methylbutanol, pentanol) 5.C 2n - Alcohol (for example, when n = 5, mainly C 10 - Alcohol) 6.C 10 - Alcohol - deficient low - boiling substances with a non - uniform proportion of water (for example, when n = 5, mainly water (non - uniform), butane, butene, C 5 - Aldehyde, 2 - methylbutanol, pentanol, nonane, α,β - unsaturated C 10 Aldehyde, C 10 - Aldehyde, α,β - unsaturated C 10 - Alcohol) 7. Aqueous phase 8.C 10 - Alcohol - deficient organic phase with a uniform proportion of water (for example, when n = 5, mainly water (uniform), butane, butene, C 5 - Aldehyde, 2 - methylbutanol, pentanol, nonane, α,β - unsaturated C 10 Aldehyde, C 10 - Aldehyde, α,β - unsaturated C 10 - Alcohol 9. Low - boiling stream (for example, when n = 5, mainly water (uniform), butane, butene, C 5 - Aldehyde, 2 - methylbutanol, pentanol, nonane) 10. Organic phase containing uniform water (for example, when n = 5, mainly water (uniform), butane, butene, C 5 - Aldehyde, 2 - methylbutanol, pentanol, nonane) 11. Aqueous phase 12. High - boiling stream (for example, when n = 5, mainly 2 - methylbutanol, pentanol, α,β - unsaturated C 10 Aldehyde, C 10 - Aldehyde, α,β - unsaturated C 10 - Alcohol) 14. High - boiling stream (for example, when n = 5, mainly α,β - unsaturated C 10 Aldehyde, C 10-aldehyde, α,β-unsaturated C 10 -alcohol) 15. High-boiling stream (e.g., when n = 5, mainly C 10 -alcohol, C10+-oligomer having more than 10 carbon atoms) 18. High-boiling stream (e.g., n = 5, mainly C10+-oligomer having more than 10 carbon atoms) 19. Reflux

Claims

1. The following steps; a) Isomer C ｎ -aldehyde (where n = 5) is subjected to aldol condensation to obtain a mixture of C ｎ - and α,β-unsaturated C ２ｎ -aldehyde, with the proportion of the unbranched aldehyde being at least 20% by weight based on the isomer C ｎ -aldehyde (where n = 5) used, and the step where it is at least 20% by weight b) hydrogenating the mixture of C obtained in step a) with α, β-unsaturated C ｎ - and α, β-unsaturated C ２ｎ - aldehyde with hydrogen to obtain a mixture of saturated C ｎ - and C ２ｎ - alcohol, and c) separating the mixture of the foregoing C ｎ - and C ２ｎ - alcohol having, Said C ｎ - and C ２ｎ - The separation step of the mixture with alcohol is carried out by at least one two-column system or at least one dividing wall column, and said C ｎ - and C ２ｎ - In the separation step of the mixture with alcohol, the mixture is taken in via the top of the at least one two-column system or at least one dividing wall column and separation occurs. When the separation step is carried out by the at least one two-column system, the water content of Cn-alcohol at the bottom of the column is less than 1000 ppm, The isomer ratio of the resulting C ｎ -alcohol is adjusted by the aldol condensation carried out in the step a), and the proportion of the linear C ｎ -alcohol is at least 10 mol% and less than 60 mol% with respect to the mixture of the isomeric C ｎ -alcohol, characterized in that the aldol condensation in step a) is carried out in the presence of an aqueous sodium hydroxide solution in a temperature range of 100 to 150 °C, Saturated C ｎ - and C ２ｎ - alcohol (wherein n = 5) production method.

2. C used in step a) above ｎ -aldehyde (where n = 5) is prepared by hydroformylating an isomeric olefin having 4 carbon atoms and synthesis gas in the presence of a hydroformylation catalyst to form the aldehyde, the method according to claim 1.

3. The method according to claim 2, characterized in that in the hydroformylation, a catalyst system containing rhodium as a central atom and complexing with ligand (1) is used. 【Chemical 1】

4. C of the step a) ｎ - The aldol condensation of the aldehyde is carried out in a tubular reactor having at least one mixing module that disperses the reactant aldehyde into droplets with an average diameter (Sauter diameter) of 0.2 mm to 2 mm in a continuous catalyst phase (process liquid) containing an aqueous sodium hydroxide solution. The method according to any one of claims 1 to 3, characterized in that.

5. C in the step a) ｎ - In the aldol condensation of the aldehyde, the reaction pressure in the reactor is in the range of 0.2 to 1.0 MPa, and the method according to claim 4 is characterized in that.

6. The hydrogenation in step b) is carried out at a temperature in the range of 170 to 200 °C and a pressure of 15×10 ５ to 30×10 ５ Pa over a supported catalyst containing at least nickel and copper as active components, the method according to any one of claims 1 to 5.

7. The method according to any one of claims 1 to 5, characterized in that the hydrogenation in step b) is carried out with hydrogen at a pressure of 5 to 100 bar and at a hydrogenation temperature of 120 to 220 °C.

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