Process for producing c9 aldehydes or c9 alcohols from butene-containing hydrocarbon streams

Abstract

The application relates to a process for producing C9 alcohols, preferably isononanol, from butene-containing hydrocarbon streams. The process comprises oligomerization of the butenes, hydroformylation of the oligomerization products to C9 aldehydes, preferably isononanal, and hydrogenation of the C9 aldehydes to obtain the C9 alcohols, preferably isononanol.

Description

[0001] Process for the production of C9 aldehydes or C9 alcohols from butene-containing hydrocarbon streams

[0002] Technical field

[0003] The present invention relates to the field of the production of C9 aldehydes and C9 alcohols, including the production of isononanal and isononanol from, preferably, butene-containing hydrocarbon streams.

[0004] Background of the invention

[0005] Isononanol (INA, for isononyl alcohol) is used, for example, as a raw material for the production of diisononyl phthalate (DINP), a phthalate plasticizer. INA consists mainly of 3,5,5-trimethyl-1-hexanol, isomeric dimethyl-1-heptanols, and isomeric methyl-1-octanols (e.g., 7-methyloctan-1-ol). The exact composition varies depending on the starting materials used, the manufacturing process, the reaction conditions, and the purification method.

[0006] INA is produced on an industrial scale by the hydrogenation of isononal (INAL, for isononyl aldehyde). INAL, in turn, is obtained by the hydroformylation of C8-rich olefin mixtures. The C8-rich olefin mixtures required for the production of INA are obtained by the oligomerization of olefins in the liquid phase, with propene and n-butene serving as the primary starting materials.

[0007] A known process for the production of olefins, for example C6-, C7-, or C8-rich olefin mixtures, is the dimersol process. The dimersol process is generally understood to be a homogeneously catalyzed oligomerization of olefins in the liquid phase at temperatures of 40 to 60 °C and pressures up to approximately 1.5 MPa to maintain the liquid phase. In the so-called Dimersol-X process, a homogeneous nickel catalyst is used in the presence of an aluminum alkyl as a cocatalyst to obtain octenes from n-butenes.

[0008] In the Dimersol-X process, the components are dosed into the feed and, after a single pass through the system, separated in an alkaline aqueous scrubbing solution. This is followed by distillation of the discharge. Catalyst recirculation is not typically included and is not readily feasible. A highly alkaline scrubbing solution containing nickel and aluminum is continuously produced, which must be processed or disposed of separately.

[0009] The prior art describes an improved process compared to the original Dimersol-X process, known as the Difasol process. This process is characterized by a heterogenized two-phase process with optimized catalyst separation, in which the nickel catalyst remains in an ionic liquid during the process. For the subprocess for the hydroformylation of C8-rich olefin mixtures, the LP-Oxo process described in WO 2020 / 240194 can be used, for example. In this process, a C8 olefin is hydroformylated in the liquid phase with a ligand-rhodium catalyst, thus converting it to a C9 aldehyde. The prior art described below provides an overview of aspects of hydroformylation as it is used as a subprocess in the combined process described here.

[0010] WO 2020 / 240194 A1 describes a process for the hydroformylation of olefins to aldehydes. The focus of this document is on the separation of the high-boiling components and INAL by passing the liquid effluent from the hydroformylation reaction in cocurrent flow with carbon monoxide through a falling film evaporator. The evaporator is operated at 1.5 bar and 120 °C. The high-boiling component, containing the Rh catalyst, is recycled to the reaction zone, and the INAL in the vapor stream is condensed and separated from CO in the expansion vessel.

[0011] WO 2021 / 091687 A1 describes a process for recovering rhodium from a hydroformylation process. The process, based on experimental results, can be divided into four steps: Treatment of a purge stream from a hydroformylation process containing the ligand-rhodium complex catalyst with an oxidizing agent and a halide-free acid. The ligand is oxidized, and rhodium is transferred from the organic phase (high-boiling-point) to the aqueous phase. Recovery of the aqueous phase. Contact of the aqueous phase with unreacted olefins from a hydroformylation process and ligand under a synthesis gas atmosphere. This concentrates the ligand-rhodium complex in the organic phase. Washing of the organic phase with a water-soluble amine. WO 2022 / 038350 A1 describes a process for the hydroformylation of C8 olefin mixtures with removal of dissolved hydrogen.It was found that the ligand-rhene complex is more stable under a CO atmosphere and that rhene losses can be reduced by removing H₂. The document describes a method for removing hydrogen from the liquid stream of a hydroformylation reactor. The reactor's liquid stream is fed countercurrently with carbon monoxide into a stripper column. The column operates at 14.5 bar and 90 °C. The hydrogen concentration in the reactor's liquid stream is reduced from 0.5 mol% to 0.02 mol%.

[0012] WO 2020 / 112373 describes a hydroformylation process. One of the most important steps in the hydroformylation process of C8 olefins with ligand-Rh catalysts is the separation of high-boiling components from the reactor stream. The Rh complex is very sensitive to high temperatures and vacuum conditions. This document claims that, during the separation of high-boiling components in a carbon monoxide evaporator, the attributability of Rh can be improved by maintaining the concentration of C8 olefins and / or mixed C9 > 1.2 wt% in the final stream of the evaporator. The object of the present invention is to optimize the hydroformylation subprocess of C8-rich olefin mixtures within a combined process for the production of isononanol.

[0013] Summary of the invention

[0014] In a first aspect, the invention is a process according to claim 1 for the production of C9 aldehydes, optionally for the production of C9 alcohols. The process comprises the steps of: A) providing an n-butene-containing hydrocarbon stream; B) oligomerizing the hydrocarbon stream using a homogeneous catalyst system comprising nickel and an aluminum alkyl, obtaining an oligomerizate containing C8 olefins; C) separating the catalyst system from the oligomerizate and working up the catalyst-free oligomerizate by distillation, yielding an oligomerization product containing at least 70 wt.-% containing C8 olefins; D) Hydroformylating a composition containing C8 olefins or hydroformylating the oligomerization product in the presence of synthesis gas using a catalyst system comprising cobalt or rhodium and a ligand, to obtain a hydroformylation mixture containing at least C9 aldehydes; and E) optionally, hydrogenating the C9 aldehydes to obtain isononanol.

[0015] In a second aspect, the invention is an apparatus according to claim 10 suitable for carrying out the process according to claim 1. The apparatus comprises the following elements: AB) a sub-plant for oligomerizing an n-butene-containing hydrocarbon stream; C) a sub-plant for processing the resulting oligomerizate; D1-10) a sub-plant for hydroformylation; and E) optionally, a sub-plant for hydrogenating C9 aldehydes. The structural features of sub-plants A) to E) are defined in claim 10.

[0016] Description of the drawings

[0017] Figure 1 shows a simplified scheme of the process of the subprocess of hydroformylation with sections 100, 200, 300, 400, 500 and 600 of the process according to the invention with essential and optional features.

[0018] Figure 2 shows a more detailed scheme of the process of the hydroformylation subprocess with sections 100, 200, 300, 400, 500 and 600 of the process according to the invention, including essential and optional features.

[0019] Figure 3 shows a more detailed scheme of the process of section 600 of the hydroformylation subprocess of the process according to the invention.

[0020] Description of the invention The above-described problem of the invention is solved by a process for the production of C9 aldehydes, wherein the process comprises the following steps:

[0021] A) Providing a hydrocarbon stream containing n-butenes;

[0022] B) Oligomerization of the hydrocarbon stream using a homogeneous catalyst system comprising a nickel compound and an aluminum compound, to obtain an oligomerizate containing C8 olefins; and

[0023] C) Separation of the catalyst system from the oligomer and distillative work-up of the oligomer freed from the catalyst system, yielding an oligomerization product as composition (010) containing at least 70 wt% C8 olefins;

[0024] Di) Feeding a composition (010) from step C) into a reactor (100) and feeding a mixture of hydrogen H2 and carbon monoxide CO, i.e. synthesis gas (020b), into the same reactor (100) to obtain a reaction mixture;

[0025] D2) Hydroformylating the reaction mixture in the reactor (100) using a catalyst system comprising cobalt or rhodium and a ligand, to obtain a hydroformylating mixture (100a) containing at least C9 aldehydes, preferably isononanal;

[0026] D3) Feeding the hydroformylation mixture (100a) into a condensation vessel (101), separating a gas phase (101a) and a liquid phase (101b) from the hydroformylation mixture (100a) and transferring the liquid phase (101b) into a stripping column

[0027] (200);

[0028] D4) Feeding carbon monoxide CO (400b) into the stripping column (200), separating a gas phase (200a) and a liquid phase (200b) from the liquid phase (101b) and transferring the liquid phase (200b) into an evaporator (300);

[0029] D5) Supplying a CO-containing gas (302a1) into the evaporator (300), separating a gas phase (300a) and a liquid phase (300b) there, transferring the gas phase (300a) into a condenser (301), and transferring the condensate (300c) into an expansion vessel (302);

[0030] De) in the expansion vessel (302) separating a gas phase (302a) and a C9 aldehyde-containing liquid phase (302b) from the liquid phase (300c);

[0031] D7) Feeding the gas phase (101 a) from step D3 into a condenser (102), in the condenser (102) separating a condensate (102b) and returning the condensate (102b) to the expansion vessel (101), and in the condenser (102) separating a recycled synthesis gas (102a) and returning the recycled synthesis gas (102a) to the reactor (100);

[0032] Ds) Feeding the gas phase (200a) from step D4 into a condenser (201), in which the condenser

[0033] (201) Separating a condensate (201 b) and returning the condensate (201 b) to the stripping column (200), and in the condenser (201) separating a recycled synthesis gas (201 a) and returning the recycled synthesis gas (201 a) to the reactor (100);

[0034] D9) Enriching a portion of the gas phase (302a) from step De with carbon monoxide CO (400b) and returning the CO-containing gas (302a1) thus obtained to the evaporator (300);

[0035] D10) Enriching a remaining part (302a2) of the gas phase (302a) with hydrogen H2 (400a) to form a recycling syngas (400a1) and returning it to the reactor (100); characterized in that such quantity of the recycled synthesizing gas (102a) as purge stream (102aP1), such quantity of the recycled synthesizing gas (201a) as purge stream (201aP2) and / or such quantity of the CO-containing gas (302a2) as purge stream (302aP3) is extracted and discarded, such that the sum of the recycled gas streams (102a), (201a) and (400a1) has a molar ratio of H2 to CO in the range of 0.9 to 1.1, or that the recycled gas streams (102a), (201a) and (400a1) are mixed with fresh synthesis gas (020a) and the synthesis gas (020b) formed thereby has a molar ratio of H2 to CO in the range of 0.9 to 1.1.

[0036] The process according to the invention for the production of C9 aldehydes comprises the preparation of the required composition containing at least 70 wt% C8 olefins. The preparation comprises the following steps preceding steps D10:

[0037] A) Providing a hydrocarbon stream containing n-butenes;

[0038] B) Oligomerization of the hydrocarbon stream using a homogeneous catalyst system comprising a nickel compound and an aluminum compound, to obtain an oligomerizate containing C8 olefins; and

[0039] C) Separation of the catalyst system from the oligomer and distillative work-up of the oligomer freed from the catalyst system, yielding an oligomerization product as composition (010) containing at least 70 wt% C8 olefins.

[0040] In step A of the process according to the invention, the hydrocarbon stream provided preferably contains 30 to 100 wt.% n-butene. Typical ranges depend on the production line into which this process is integrated. If butane-butene separation is used, streams with over 98 wt.% n-butene can be obtained. However, if, for example, a C4 raffinate is used, a stream containing 30 to 85 wt.% n-butene can be provided. If other by-streams are to be utilized, the olefin content can also be lower. Below a content of 20 wt.% n-butene, economical oligomerization is hardly possible.

[0041] The homogeneous catalyst system used in the oligomerization step B) contains a nickel compound and an aluminum alkyl. Corresponding homogeneous catalyst systems are known to those skilled in the art, for example from US 2013 / 0158321 A1.

[0042] The nickel compound for the catalyst system in step B) can be a nickel carboxylate in which nickel is present as nickel(II) and has two carboxylic acid salt groups. Suitable acid salts are octoate, 2-ethylhexanoate, decanoate, stearate, oleate, salicylate, and hydroxydecanoate. A particularly preferred nickel carboxylate is nickel(II) ethylhexanoate. According to the present invention, the nickel compound can also be a nickel complex. An example of this is nickel(II) acetylacetonate. Other suitable complexes are complexes of nickel halides, nickel sulfates, nickel octoate, or nickel alkoxides. However, nickel complexes with a oxidation state of less than 2 can also be used, for example, nickel biscyclooctadiene, metallylnickel chloride, bisallylnickel, allylnickel chloride, and allylnickel bromide.Suitable nickel compounds are preferably nickel(II) chloride, nickel(II)(dimethoxyethane) chloride, nickel(II) bromide, nickel(II)(dimethoxyethane) bromide, nickel(II) fluoride, nickel(II) iodide, nickel(II) sulfate, nickel(II) carbonate, nickel(II) dimethylglyoxime, nickel(II) hydroxide, nickel(II) hydroxyacetate, nickel(II) oxalate, nickel(II) carboxylates such as nickel 2-ethylhexanoate, nickel(II) phenate, nickel(II) naphthenate, nickel(II) acetate, nickel(II) trifluoroacetate, nickel(II) triflate, nickel(II) acetylacetonate, nickel(II) hexafluoroacetylacetonate, tri-allylnickel(II) chloride, tri-allylnickel(II) bromide, and methylallylnickel(II) chloride dimer. r|3-Allylnickel(II) hexafluorophosphate, r|3-Methallylnickel(II) hexafluorophosphate, nickel(II)-1,5-cyclooctadienyl, or mixtures thereof. These nickel compounds in their hydrated or non-hydrated form.

[0043] The aluminum compound for the catalyst system in step B) can be an alkylaluminium compound, a mixture of alkylaluminium compounds, a halogenoalkylaluminium compound, or a mixture of halogenoalkylaluminium compounds. Suitable aluminum compounds are methylaluminium dichloride (MeAlCh), ethylaluminium dichloride (EtAlCh), dithylaluminium chloride (Et₂AlCl), diisobutylaluminium chloride (iBu₂AlCl), and isobutylaluminium dichloride (iBuAlCh). A particularly preferred aluminum compound is ethylaluminium dichloride (EtAlCh) or mixtures thereof. The use of halogenoaluminates or organohalogenoaluminates is also possible, preferably as the cationic component of an ionic liquid.

[0044] Depending on the specific embodiment, the catalyst system for the oligomerization in step B) may contain additional components.

[0045] The catalyst system can, for example, contain a Brønsted acid. Suitable Brønsted acids are carboxylic or sulfonic acids and their derivatives. A preferred class is halogenocarboxylic acids. Examples include trifluoroacetic acid, difluoroacetic acid, fluoroacetic acid, trichloroacetic acid, dichloroacetic acid, and chloroacetic acid. However, it is also possible to use arilsulfonic acids, alkylsulfonic acids, fluoroalkylsulfonic acids, picric acid, or nitroacetic acid. Trifluoroacetic acid is particularly preferred as the Brønsted acid.

[0046] The catalyst system for step B) may also contain a Lewis acid, provided no Brønsted acid is present. Suitable Lewis acids are diethyl ether, methyl tert-butyl ether, tetrahydrofuran, 1,4-dioxanes, isoxazole, pyridine, pyrazine, and pyrimidine.

[0047] It is also possible that the catalyst system in step B) comprises an organic polyol such as ethylene glycol. Furthermore, improved selectivity can be achieved through the presence of organophosphorus ligands. Examples of suitable ligands are phosphine ligands, which comprise three identical hydrocarbon groups. Examples of hydrocarbon groups are phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, 3,5-dimethylphenyl, 4-n-butylphenyl, 4-methoxyphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 2-isopropoxyphenyl, 4-methoxy-3,5-dimethylphenyl, 3,5-di-tert-butyl- 4-methoxyphenyl, 4-chlorophenyl, 3,5-di(trifluoromethyl)phenyl, benzyl, naphthyl, bisnaphthyl, pyridyl, bisphenyl, furanyl, thiophenyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl I, cyclopentyl, cyclohexyl, and adamantyl. Preferred phosphine ligands are tri-n-butylphosphine, tricyclohexylphosphine, triisopropylphosphine or triphenylphosphine.In a preferred embodiment, the molar ratio of the phosphine ligand to the nickel compound is in the range of 5 to 25, preferably in the range of 5 to 20, even more preferably in the range of 5 to 15.

[0048] If the catalyst system contains a nickel complex, the oligomerization in step B) can be carried out in two phases using an ionic liquid. The ionic liquid preferably comprises at least one salt with the formula Q+A-, where Q+ is a quaternary ammonium cation, a phosphonium cation, a mixture of ammonium and phosphonium cations, or a lithium cation, and A- is a coordinating or non-coordinating anion selected from the group consisting of halogenoaluminates, organohalogenoaluminates, organogallates, organohalogenogallates, or a mixture of at least two of these compounds.

[0049] Without the use of an ionic liquid, a single-phase liquid mixture of the catalyst system and the oligomerization in step b) is present. The components of the catalyst system can be mixed in a solvent at a controlled temperature and for a specific time. Suitable solvents include alkanes, aromatic hydrocarbons, halogenated hydrocarbons, or the olefins produced during the oligomerization in step b), in this case, C8 olefins. Mixing with stirring is preferably carried out under an inert atmosphere of nitrogen or argon. The mixing temperature is preferably in the range of 0°C to 80°C, and more preferably in the range of 10°C to 60°C.

[0050] The oligomerization in step B) is preferably carried out at a temperature of -20°C to 80°C, preferably at a temperature of 20°C to 60°C, under pressure conditions so that the reaction mixture is kept in the liquid phase or in a condensed phase.

[0051] The oligomerization in step B) can be carried out in one or more reactors. Suitable reactors are known to those skilled in the art. An example of a suitable reactor is a continuously stirred tank reactor (CSTR). In a preferred embodiment, the oligomerization is carried out in a reaction zone containing several identical or different reactors. The reactors can be connected in parallel or in series. Preferably, a cascade of several reactors connected in series is used. Each reactor can have a separate dosing system for the catalyst.

[0052] The oligomerization process yields an oligomer containing the C8 butenes. The homogeneously dissolved catalyst system may also be present in the oligomer.

[0053] The catalyst system is then separated from the oligomer. This process begins with the destruction of the catalyst system. Such methods are known to those skilled in the art. For example, this can be achieved by alkaline washing with an alkaline washing solution, during which the nickel passes into the aqueous phase. Subsequently, an aqueous wash can be performed to remove any remaining alkaline washing solution. The remaining oligomer remains as the organic phase.

[0054] The oligomerized product freed from the catalyst system is then subjected to distillative work-up, yielding an oligomerization product as composition (010) containing at least 70 wt% C8 olefins.

[0055] Distillation processes are known to those skilled in the art. The distillation conditions, such as temperature and pressure, are usually determined by the column design (column height, number of trays, type of trays or packing, spacing, etc.). During operation, the separation properties of the distillation can be further controlled by the temperature distribution and / or the heat input in the column and the reflux in the distillate. Likewise, the separation properties can be adjusted within a certain range by changing the pressure. Therefore, the precise settings cannot be defined in a general way and independently of the distillation column design. This is known to those skilled in the art. In a preferred embodiment, the pressure during distillation in step C) is in the range of 1 to 6 bar absolute, particularly preferably in the range of 2 to 5 bar absolute.The temperature at the top of the distillation column is preferably in the range of 15 to 60 °C, particularly preferably in the range of 25 to 50 °C.

[0056] After the production of the C8 olefins or the composition (010), steps Di) to Dio) are carried out: Di) Feeding the composition (010) from step C) into a reactor (100) and feeding a mixture of hydrogen H2 and carbon monoxide CO, i.e. synthesis gas (020b), into the same reactor (100) to obtain a reaction mixture;

[0057] D2) Hydroformylating the reaction mixture in the reactor (100) using a catalyst system comprising cobalt or rhodium and a ligand, to obtain a hydroformylating mixture (100a) containing at least C9 aldehydes, preferably isononanal;

[0058] D3) Feeding the hydroformylation mixture (100a) into a condensation vessel (101), separating a gas phase (101a) and a liquid phase (101b) from the hydroformylation mixture (100a) and transferring the liquid phase (101b) into a strip column (200);

[0059] D4) Feeding carbon monoxide CO (400b) into the stripping column (200), separating a gas phase (200a) and a liquid phase (200b) from the liquid phase (101b) and transferring the liquid phase (200b) into an evaporator (300);

[0060] D5) Supplying a CO-containing gas (302a1) into the evaporator (300), separating a gas phase (300a) and a liquid phase (300b) there, transferring the gas phase (300a) into a condenser (301), and transferring the condensate (300c) into an expansion vessel (302);

[0061] De) in the expansion vessel (302) separating a gas phase (302a) and a C9 aldehyde-containing liquid phase (302b) from the liquid phase (300c);

[0062] D7) Feeding the gas phase (101 a) from step D3 into a condenser (102), in the condenser (102) separating a condensate (102b) and returning the condensate (102b) to the expansion vessel (101), and in the condenser (102) separating a recycled synthesis gas (102a) and returning the recycled synthesis gas (102a) to the reactor (100);

[0063] Da) Feeding the gas phase (200a) from step Ü4 into a condenser (201), in the condenser (201) separating a condensate (201b) and returning the condensate (201b) to the stripping column (200), and in the condenser (201) separating a recycled synthesis gas (201a) and returning the recycled synthesis gas (201a) to the reactor (100);

[0064] D9) Enriching a portion of the gas phase (302a) from step De with carbon monoxide CO (400b) and returning the CO-containing gas (302a1) thus obtained to the evaporator (300);

[0065] D10) Enriching a remaining part (302a2) of the gas phase (302a) with hydrogen H2 (400a) to form a recycling syngas (400a1) and returning it to the reactor (100);

[0066] The C9 aldehyde-containing liquid phase (302b) separated in step De) contains the desired product of the process according to the invention. To isolate the product, the liquid phase (302b) can be transferred to a distillation column (500) for the separation of the C9 aldehydes (500a), preferably for the separation of isononanal.

[0067] The process according to the invention can be extended to a process for the production of C9 alcohols. In such a process, steps Di) to D10) are followed by a step E) in which the obtained C9 aldehydes (500a), preferably isononanal, are hydrogenated to obtain C9 alcohols, preferably isononanal. The hydrogenation is a process known to those skilled in the art and is not described in detail here.

[0068] The hydroformylation of the reaction mixture in step D2 can be carried out in various ways and under different reaction conditions. For example, the hydroformylation can be performed at a temperature in the range of 90 to 150 °C, preferably 110 to 130 °C, and at a pressure in the range of 10 to 40 bar, preferably 15 to 25 bar.

[0069] Rhodium can be used as a catalyst system in a concentration of 5 ppm to 500 ppm, preferably 100 ppm to 300 ppm, based on the total reaction mixture in the hydroformylation, with Alkanox 240 (= Tris(2,4-di-tert-butylphenyl)phosphite, CAS No.: 31570-04-4) as ligand P in a concentration of 1 mol P / mol Rh to 50 mol P / mol Rh.

[0070] The hydroformylation mixture obtained in step D2 typically contains 60 to 90 wt%, preferably 70 to 80 wt%, C9 aldehydes, 10 to 30 wt% unreacted C8 olefins, 0.01 to 5 wt% byproducts (for example, paraffins, alcohols, and other compounds), 0 to 5 wt% heavy substances, and 0 to 5 wt% synthesis gas. It is understood that the sum of all components equals 100 wt%.

[0071] In step D4, pure carbon monoxide (>99 wt.%) CO can be supplied, but gas mixtures containing a high proportion, i.e., >80 wt.%, of CO can also be used. The CO-containing gas supplied in D5 can be pure carbon monoxide (>99 wt.%) CO) or a gas with a lower CO content, for example, 90 to 98 wt.%, preferably 95 to 98 wt.% CO.

[0072] In step D5, the mixing ratio of the liquid phase (200b) and the CO-containing gas (302a1) is 200b / 302a1, preferably in the range of 0.2 to 0.6, more preferably in the range of 0.3 to 0.5. Typical flow rates during operation are 30,000 to 48,000 kg / h for the liquid phase (200b), and 80,000 to 150,000 kg / h for the CO-containing gas (302a1).

[0073] In step D9, the enrichment with carbon monoxide CO (400b) is carried out such that a CO-containing gas (302a1) with the following composition is preferably obtained: 0.1 to 0.5 wt.%, preferably 0.2 to 0.4 wt.% hydrogen H2, 90 to 99 wt.%, preferably 95 to 98 wt.% carbon monoxide CO, 1 to 3 wt.%, preferably 1.5 to 2.0 wt.% C8 olefins, 0 to 0.5 wt.%, preferably 0.2 to 0.4 wt.% by-products (e.g. paraffins, alcohols, etc.), and 0 to 0.5 wt.%, preferably 0.2 to 0.4 wt.% C9 aldehydes.

[0074] In the processes according to the invention for the production of C9 aldehydes or C9 alcohols, a cold box (400) can be provided. In this case, the carbon monoxide (400b) fed into the stripping column (200) in step D4) can originate from the cold box (400). Independently of step D4), the carbon monoxide (400b) enriching the gas phase (302a) in step D9) can also originate from the cold box (400). The same applies to step D10), in which, independently of steps D4) and D9), the hydrogen H2 (400a) enriching the gas phase (302a2) can originate from the cold box (400). Several cold boxes (400) can also be provided, with, for example, a different cold box (400) being used for each of steps D4), D9), and D10).

[0075] The cold box(es) (400) are supplied with synthesis gas (400c), which can be diverted from the synthesis gas (020a) fed into the reactor (100). Of course, the synthesis gas (400c) can also be supplied from another synthesis gas source.

[0076] The present invention also relates to a plant for the production of C9 aldehydes.

[0077] The plant can optionally be expanded to produce C9 alcohols. The plant includes the following elements:

[0078] D1-2) a reactor (100) for hydroformylating a reaction mixture to obtain a hydroformylating mixture (100a), a feed line into the reactor (100) for a composition containing at least 70 wt% C8 olefins (010) and a feed line into the reactor (100) for synthesis gas (020b);

[0079] D3) a condensing vessel (101), a feed line to it for the hydroformylation mixture (100a), a discharge line (101a) from there for a separated gas phase and a discharge line (101b) from there for a separated liquid phase, and a stripping column (200) into which the discharge line (101b) leads; T4) a feed line for carbon monoxide CO (400b) into the stripping column (200), a discharge line (200a) from there for a separated gas phase and a discharge line (200b) from there for a separated liquid phase, and an evaporator (300) into which the discharge line (200b) leads;

[0080] D5) a feed line (302a1) into the evaporator (300) for a CO-containing gas, a discharge line (300a) from there for a separated gas phase and a discharge line (300b) from there for a separated liquid phase, a condenser (301) into which the discharge line (300a) leads, an expansion vessel (302), a discharge line (300c) for condensate from the condenser (301) into the expansion vessel (302);

[0081] De) a discharge line (302a) from the expansion vessel (302) for a separated gas phase and a discharge line (300b) from the expansion vessel (302) for a separated liquid phase, and, optionally, a distillation column (500) for the separation of C9 aldehyde, into which the discharge line (302b) leads, and a discharge line (500a) for the separated C9 aldehyde;

[0082] D7) a condenser (102) into which a supply line (101a) for a gas phase leads, a return line (101b) for a condensate from the condenser (102) into the expansion vessel

[0083] (101), a return line (102a) for separated recycling synthesis gas from the condenser

[0084] (102) into the reactor (100);

[0085] Da) a condenser (201) into which a feed line (200a) for a gas phase leads, a return line (201b) for a condensate from the condenser (201) into the stripping column (200), a return line (201a) for a separated recycling synthesis gas from the condenser (201) into the reactor (100);

[0086] D9) a supply line (400b) for carbon monoxide CO to the discharge line (302a) from the expansion vessel (302), an extension line (302a1) for CO-containing gas from the discharge line (302a) to the evaporator (300);

[0087] D10) a discharge line (302a2) leading from the discharge line (302a), a supply line (400a) for hydrogen H2 to the discharge line (302a2), a return line (400a1) for a formed recycling synthes gas from the supply line (400a) into the reactor (100);

[0088] E) optional, a sub-plant for hydrogenating the C9 aldehydes discharged via the discharge line (500a) to obtain C9 alcohols, characterized in that the plant comprises the following further elements: a purge flow line (102aP1) for extracting a quantity of gas from the return line (102a), a purge flow line (201aP2) for extracting a quantity of gas from the return line (201a), and a purge flow line (302a2P3) for extracting a quantity of gas from the discharge line (302a2).

[0089] The inventive plant for the production of C9 aldehydes or the extended plant for the production of C9 alcohols can be supplemented by sub-plants for the production of the required composition containing the C8 olefins. Such a supplemented plant comprises the following elements preceding elements Di) to D10):

[0090] AB) a sub-plant for oligomerizing a hydrocarbon stream containing n-butene using a catalyst system to obtain a C8 olefin-containing oligomerizate; and C) a sub-plant for separating the catalyst system from the oligomerizate and for distillatively working up the oligomerizate to obtain an oligomerization product as composition (010).

[0091] The apparatus according to the invention for the production of C9 aldehydes or C9 alcohols can include a cold box (400). In this case, the supply line for carbon monoxide (CO) (400b) in element D4) can originate from the cold box (400). Independently of element D4), the supply line (400b) for carbon monoxide (CO) in element D9) can also originate from the cold box (400). The same applies to element D10), in which the supply line (400a) for hydrogen (H2) can originate from the cold box (400), independent of elements D4) and D9). Several cold boxes (400) can also be provided, with, for example, a different cold box (400) being used in each of elements D4), D9), and D10).

[0092] If one or more cold boxes (400) are present, one or more synthesis gas lines (400c) lead to them, branching off from the synthesis gas supply line (020b) to the reactor (100). Of course, the one or more synthesis gas lines (400c) can also lead to the cold box(es) (400) from one or more other synthesis gas sources.

[0093] Within the scope of the present invention, it is preferred that the C9 aldehydes correspond to a composition containing, predominantly containing, or substantially consisting of isononanal. Similarly, it is preferred that the C9 alcohols correspond to a composition containing, predominantly containing, or substantially consisting of isononanol. "Contains" means that the composition comprises isononanal or isononanol in an amount ranging from 10 wt.% to 50 wt.%. "Predominantly contains" means that the composition comprises isononanal or isononanol in an amount ranging from over 50 wt.% to 90 wt.%. "Consists substantially of" means that the composition comprises isononanal or isononanol in an amount ranging from over 90 wt.% to 100 wt.%.

[0094] The advantages, details and features of the invention will become clear with reference to the example explained below and to Figures 1, 2 and 3.

[0095] Figure 1 shows the division of the process steps D) according to the invention into 6 sections:

[0096] 1. Hydroformylation (Section 100),

[0097] 2. Removal of dissolved hydrogen H2 (Section 200),

[0098] 3. Separation of heavy boiling points (Section 300),

[0099] 4. Separation of carbon monoxide CO and hydrogen H2 and recycling of synthesis gas (Section 400),

[0100] 5. Purification INAL (Section 500), and

[0101] 6. Catalyst Recovery (Section 600). The catalyst can be recycled to the reaction zone (Section 100) dissolved in high-boiling components (from Section 300) and / or dissolved in unreacted C8 olefins (from Section 600). The synthesis gas stream is split into at least two fractions. One fraction is mixed with recycled synthesis gas and fed to the hydroformylation stage (Section 100). The other fraction of the synthesis gas is routed to Section 400. There, carbon monoxide (CO) is separated from hydrogen (H2), for example, using a membrane separation process or a cold box. The CO is routed to Sections 200 and 300 and used there. The gas streams from Sections 200 and 300 are mixed with the H2 stream from Section 400 to form the recycled synthesis gas.

[0102] Figure 2 shows the hydroformylation step of the process according to the invention in more detail. The hydroformylation for the production of isononanal from C8 olefins using synthesis gas was simulated. The simulation was performed using the software Aspen Plus, and the construction of the property model was validated with available experimental data on the thermophysical properties of pure components and mixtures.

[0103] C8 olefins at a mass flow rate of 23 t / h are fed into the hydroformylation reactor (100) along with synthesis gas. The molar ratio of CO to H2 in the synthesis gas (020b) is approximately 1:1, and CO is supplied with a stoichiometric excess of 1.02. The reaction is carried out at 120 °C, 20 bar pressure, and a rhodium catalyst concentration of 100 ppm. The concentrations of the components in the C8 olefin feed stream are: 8 wt% n-octene, 62 wt% methylheptene, and 30 wt% dimethylhexene. In the simulation, the conversion of C8 olefins and the INAL selectivity are calculated according to Tables 2 and 3. A reactor residence time of 180 minutes is used. The vapor phase and the liquid phase of the reactor outflow are separated in the expansion vessel (101) at the reactor outlet pressure and 90 °C.A portion of the unreacted olefins and reaction products in the vapor stream is condensed in the heat exchanger (102) at 45 °C and returned to the container (101).

[0104] The liquid stream from (101) is fed to the H2 strip column (200). The strip column has two theoretical stages and operates at a top pressure of 14.5 bar. 130 Nm³ are present in the column bottom. 3 CO is supplied per hour. The concentration in the liquid stream is reduced from 0.72 mol% to 0.12 mol%. The vapor stream from the top of the strip column (200) is cooled to 45 °C, and the condensed liquid stream is recycled back to column c.

[0105] The liquid flow from the sump of the strip column (200) is forced countercurrently at 116,425 Nm 3CO is fed into the falling film evaporator (300) at a rate of 1.5 bar per hour. The evaporator operates at 120 °C and a pressure of 1.5 bar. High-boiling substances with a concentration of 5 wt% INAL are separated in the liquid stream (liquid discharge) of the evaporator. A fraction of the high-boiling substances is recycled to the reaction section, and 564 kg / h are fed to the rhizome recovery section. The mass ratio of feed-in to liquid discharge in the evaporator is set to 3.9 in the simulation. The vapor stream from the evaporator (300) is cooled to a temperature of 20 °C in the heat exchanger (301) and directed into the expansion vessel (302) to separate the gas and liquid phases. The CO-containing gas phase is fed to the compressor (303) to overcome pressure losses. Part of the output stream is mixed with CO from the cold box (400) and returned to the evaporator (300). The remainder is mixed with the Fh stream separated in the cold box (400).The reformed synthesis gas is recompressed in the multi-stage compressor with intercooling (401) to a pressure just above the pressure of the reaction section.

[0106] The INAL product is separated in the distillation column (500). The column has 33 theoretical stages and a partial condenser, operating at 20 °C and a top pressure of 0.2 bar. Unreacted olefins and alkanes are separated at the top of the column. 99.9% INAL with a purity of 99.84 wt% is recovered at the bottom of the column. Part of the unreacted C8 olefins is recycled back to the reactor; the other fraction is mixed with ligand and fed to the rhizome recovery section. The recycled stream of unreacted C8 olefins is 4.8 t / h in the baseline simulation, resulting in 25.9 t / h of INAL production.

[0107] The distillation column in section (500) has a partial condenser at the top. C8 aldehydes are separated at the bottom of the column, and the unreacted C8 olefins and byproducts (paraffins, alcohols, and others) are separated at the top. The liquid product stream at the top of the distillation column is split into three parts: (1) One fraction is directed to section (600) and used in the process for rhodium recovery, (2) the other fraction is directed to the reaction section (100) for further reaction of the unreacted C8 olefins in order to achieve the required input factor (t INA / t C8 olefin = x), and (3) the third fraction is purged to prevent accumulation of the byproducts (paraffins and others).

[0108] Figure 3 shows an example of catalyst recovery (section 600). High-boiling rhodium with a concentration of 389 ppm is fed into section 600. Oxidation is carried out at 65 °C with air and 50–70 wt% aqueous acetic acid. The oxidation reaction can take place in one or more reactors connected in series. Each reactor is followed by a decanter for separating the organic and aqueous phases. The organic product phase from the first reactor is fed into the next reactor and treated with air and acetic acid. All aqueous product streams from the oxidation reaction are mixed and fed with nitrogen (N₂) into the expansion vessel (601). The liquid product is then fed into reactor (602) for rhodium extraction in a synthesis gas atmosphere from the mixture of unreacted C₈ olefins and ligand. The reactor operates at a temperature in the range of 65–100 °C and a pressure between 3.5–20 bar.The gas phase is separated in the expansion vessel (603) and the aqueous phase in the decanter (604). To remove traces of acid, the organic phase from the decanter (604), which contains the ligand-Rh complex, is washed in the extraction column (605) with a water-soluble amine, e.g., triethanolamine. The rhodium recovered in the organic phase is recycled to the hydroformylation reactor (100). Synthesis gas (020, 102a, 201a, 400a1) is used as the reactant in the hydroformylation of C8 olefins. CO (400b) separated from the synthesis gas is used in the stripping column (200) and / or in the falling film evaporator (300) for H2 removal. A fraction (302a2) of the CO-rich gas stream from section (300) is mixed with H2 to form your newly formed synthesis gas (400a1), which is returned to the hydroformylation reactor (100).Excess synthesis gas, which is separated in the container (101), is also returned to the reactor (100).

[0109] In the event that the molar ratio of H2 to CO in the fresh synthesis gas stream (020a) is 1 : 1, the withdrawals of CO / H2-containing gases via the purge streams (102aP1), (201 aP2) and (302a2P3) are adjusted so that the recycling gas streams (102a), (201 a) and (400a1) together have a molar ratio of H2 to CO in the range of 1 : 1.

[0110] In the event that the molar ratio of H2 to CO in the fresh synthesis gas stream (020a) is not 1 : 1, the withdrawals of CO / H2-containing gases via the purge streams (102aP1), (201 aP2) and (302a2P3) are adjusted so that the synthesis gas stream (020b) has a value that is in the range of 1 : 1.

[0111] The use of fresh synthesis gas (020a) can be minimized by recovering excess synthesis gas in section 100 (102a) and reusing it in hydroformylation (100) or by generating and reusing synthesis gases in sections 200 (201a) and 400 (400a1).

Claims

Patent claims 1. A process for the production of C9 aldehydes, the process comprising the following steps: A) Providing a hydrocarbon stream containing n-butenes; B) Oligomerizing the hydrocarbon stream using a homogeneous catalyst system comprising nickel and an aluminum alkyl, to obtain an oligomerizate containing C8 olefins; C) Separation of the catalyst system from the oligomer and distillative work-up of the oligomer freed from the catalyst system, yielding an oligomerization product as composition (010) containing at least 70 wt% C8 olefins; Di) Feeding a composition (010) from step C) into a reactor (100) and feeding a mixture of hydrogen H2 and carbon monoxide CO, i.e. synthesis gas (020b), into the same reactor (100) to obtain a reaction mixture; D2) Hydroformylating the reaction mixture in the reactor (100) using a catalyst system comprising cobalt or rhodium and a ligand, to obtain a hydroformylating mixture (100a) containing at least C9 aldehydes; D3) Feeding the hydroformylation mixture (100a) into a condensation vessel (101), separating a gas phase (101a) and a liquid phase (101b) from the hydroformylation mixture (100a) and transferring the liquid phase (101b) into a strip column (200); D4) Feeding carbon monoxide CO (400b) into the stripping column (200), separating a gas phase (200a) and a liquid phase (200b) from the liquid phase (101b) and transferring the liquid phase (200b) into an evaporator (300); D5) Supplying a CO-containing gas (302a1) into the evaporator (300), separating a gas phase (300a) and a liquid phase (300b) there, transferring the gas phase (300a) into a condenser (301), and transferring the condensate (300c) into an expansion vessel (302); De) in the expansion vessel (302) separating a gas phase (302a) and a C9 aldehyde-containing liquid phase (302b) from the liquid phase (300c); D7) Feeding the gas phase (101a) from step D3 into a condenser (102), separating a condensate (102b) in the condenser (102) and returning the condensate (102b) to the expansion vessel (101), and separating a Recycling synthesis gas (102a) and recirculation of the recycling synthesis gas (102a) into the reactor (100); Da) Feeding the gas phase (200a) from step Ü4 into a condenser (201), in the condenser (201) separating a condensate (201b) and returning the condensate (201b) to the stripping column (200), and in the condenser (201) separating a recycled synthesis gas (201a) and returning the recycled synthesis gas (201a) to the reactor (100); D9) Enriching a portion of the gas phase (302a) from step De with carbon monoxide CO (400b) and returning the CO-containing gas (302a1) thus obtained to the evaporator (300); D10) Enriching a remaining part (302a2) of the gas phase (302a) with hydrogen H2 (400a) to form a recycling syngas (400a1) and returning it to the reactor (100); characterized in that such quantity of the recycled synthesizing gas (102a) as purge stream (102aP1), such quantity of the recycled synthesizing gas (201a) as purge stream (201aP2) and / or such quantity of the CO-containing gas (302a2) as purge stream (302aP3) is extracted and discarded, such that the sum of the recycled gas streams (102a), (201a) and (400a1) has a molar ratio of H2 to CO in the range of 0.9 to 1.1, or that the recycled gas streams (102a), (201a) and (400a1) are mixed with fresh synthesis gas (020a) and the synthesis gas (020b) formed thereby has a molar ratio of H2 to CO in the range of 0.9 to 1.

1.

2. The method of claim 1, wherein the aluminum compound of the catalyst system in step B) is methylaluminum dichloride (MeAlCh), ethylaluminum dichloride (EtAlCh), dithylaluminum chloride (Et₂AlCl), diisobutylaluminum chloride (iBu₂AlCl), and isobutylaluminum dichloride (iBuAlCh). A particularly preferred aluminum compound is ethylaluminum dichloride (EtAlCh) or a mixture thereof.

3. The method of claim 1 or 2, wherein the nickel compound of the catalyst system in step B) comprises nickel(II) chloride, nickel(II)(dimethoxyethane) chloride, nickel(II) bromide, nickel(II)(dimethoxyethane) bromide, nickel(II) fluoride, nickel(II) iodide, nickel(II) sulfate, nickel(II) carbonate, nickel(II) dimethylglyoxime, nickel(II) hydroxide, nickel(II) hydroxyacetate, nickel(II) oxalate, nickel(II) carboxylates such as nickel 2-ethylhexanoate, nickel(II) phenate, nickel(II) naphthenate, nickel(II) acetate, nickel(II) trifluoroacetate, nickel(II) triflate, nickel(II) acetylacetonate, nickel(II) hexafluoroacetylacetonate, ir-allylnickel(II) chloride, ir-allylnickel(ll) bromide, methallylnickel(ll) chloride dimer, r|3-allylnickel(ll) hexafluorophosphate, r|3-methallylnickel(ll) hexafluorophosphate, nickel(ll)-1,5-cyclooctadienyl or a mixture thereof.

4. Method according to one of the preceding claims, wherein the oligomerization in step B) is carried out at a temperature of -20°C to 80°C.

5. Method according to one of the preceding claims, wherein the oligomerization is carried out in a reaction zone containing several identical or different reactors, preferably a cascade of several reactors connected in series.

6. Method according to any of the preceding claims, wherein a coldbox (400) is provided and in step D4) the carbon monoxide (400b) supplied to the strip column (200) comes from the coldbox (400), and / or wherein in step D9) the carbon monoxide (400b) enriching the gas phase (302a) comes from the coldbox (400), and / or wherein in step D10) the hydrogen H2 (400a) enriching the gas phase (302a2) comes from the coldbox (400).

7. Method according to one of the preceding claims, wherein the coldbox (400) is supplied with synthesis gas (400c) which is diverted from the synthesis gas (020a).

8. Method according to one of the preceding claims, wherein the C9 aldehyde-containing liquid phase (302b) separated in step De) is transferred to a distillation column (500) for the separation of the C9 aldehydes (500a).

9. Method according to one of the preceding claims, wherein steps Di) to D10) are followed by a step E) in which the obtained C9 aldehydes (500a) are hydrogenated to obtain C9 alcohols.

10. Plant for the production of C9 aldehydes, optionally for the production of C9 alcohols, the plant comprising the following elements: AB) a sub-plant for oligomerizing an n-butene-containing hydrocarbon stream using a catalyst system to obtain an oligomerizate containing C8 olefins; C) a sub-plant for separating the catalyst system from the oligomer and suitable for the distillative work-up of the oligomer to obtain an oligomerization product (010); D1-2) a reactor (100) for hydroformylating a reaction mixture to obtain a hydroformylation mixture (100a), a feed line into the reactor (100) for the oligomerization product (010) and a feed line into the reactor (100) for synthesis gas (020b); D3) a decompression vessel (101), a feed line therein for the hydroformylation mixture (100a), a discharge line (101a) from there for a separated gas phase and a discharge line (101 b) from there for a separated liquid phase, and a stripping column (200) into which the discharge line (101 b) leads; D4) a feed line for carbon monoxide CO (400b) into the stripping column (200), a discharge line (200a) from there for a separated gas phase and a discharge line (200b) from there for a separated liquid phase, and an evaporator (300) into which the discharge line (200b) leads; D5) a feed line (302a1) into the evaporator (300) for a CO-containing gas, a discharge line (300a) from there for a separated gas phase and a discharge line (300b) from there for a separated liquid phase, a condenser (301) into which the discharge line (300a) leads, an expansion vessel (302), a discharge line (300c) for condensate from the condenser (301) into the expansion vessel (302); De) a discharge line (302a) from the expansion vessel (302) for a separated gas phase and a discharge line (300b) from the expansion vessel (302) for a separated liquid phase, and, optionally, a distillation column (500) for the separation of C9 aldehyde, into which the discharge line (302b) leads, and a discharge line (500a) for the separated C9 aldehyde; D7) a condenser (102) into which a feed line (101 a) for a gas phase leads, a return line (101 b) for a condensate from the condenser (102) into the expansion vessel (101), a return line (102a) for a separated recycling synthesis gas from the condenser (102) into the reactor (100); Da) a condenser (201) into which a feed line (200a) for a gas phase is directed, a return line (201b) for a condensate from the condenser (201) into the stripping column (200), a return line (201a) for a separated recycling synthesis gas from the condenser (201) into the reactor (100); D9) a supply line (400b) for carbon monoxide CO to the discharge line (302a) from the expansion vessel (302), an extension line (302a1) for CO-containing gas from the discharge line (302a) to the evaporator (300); D10) a discharge line (302a2) leading from the discharge line (302a), a supply line (400a) for hydrogen H2 to the discharge line (302a2), a return line (400a1) for a formed recycling synthes gas from the supply line (400a) into the reactor (100); E) optional, a sub-plant for hydrogenating the C9 aldehydes discharged via the discharge line (500a) to obtain C9 alcohols, characterized in that the plant comprises the following further elements: a purge line (102aP1) for extracting a quantity of gas from the return line (102a), a purge line (201aP2) for extracting a quantity of gas from the return line (201a), and a purge line (302a2P3) for extracting a quantity of gas from the discharge line (302a2).

11. System according to claim 10, wherein the system comprises a cold box (400), and in element D4) the supply line for carbon monoxide CO (400b) from the cold box (400) comes, and / or wherein in element D9) the supply line (400b) for carbon monoxide CO from the cold box (400) comes, and / or wherein in element D10) the supply line (400a) for hydrogen H2 from the cold box (400) comes.

12. Plant according to claim 11, wherein a synthesis gas line (400c) branches off from the synthesis gas supply line (020b) and leads to the cold box (400).

13. Method or apparatus according to any of the preceding claims, wherein the C9 aldehydes correspond to a composition containing, predominantly containing or consisting of isononanal, and / or wherein the C9 alcohols correspond to a composition containing, predominantly containing or consisting of isononanal.

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