Method for producing aldehyde

Abstract

Process for producing 3,5,5-trimethylhexanal, which is a process for producing 3,5,5-trimethylhexanal by reacting diisobutene (DIB) with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst, the production process comprising: a step of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 to 85% (first-stage reaction step); a step of separating unreacted DIB from the reactants obtained in the aforementioned first-stage reaction step (unreacted DIB separation step); and a step of reacting the separated unreacted DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst (second-stage reaction step).

Description

Technical Field

[0001] The present invention relates to a method for producing 3,5,5-trimethylhexanal, which is useful as a raw material for carboxylic acids and the like that are raw materials for refrigeration oils and the like, and the like. Background Art

[0002] Conventionally, a method of reacting a monoolefin with carbon monoxide and hydrogen to produce a saturated aliphatic aldehyde and a saturated aliphatic alcohol having one more carbon atom than the monoolefin (oxo reaction) has been widely used as an oxo synthesis process. The aldehyde having one more carbon atom than the monoolefin obtained by the oxo reaction using a monoolefin as a raw material becomes a raw material for carboxylic acids that are useful as raw materials for refrigeration oils and the like. Since carboxylic acids are obtained by oxidation of aldehydes, in order to obtain a desired carboxylic acid, it is desirable to selectively and highly yield the corresponding aldehyde.

[0003] Among the methods for producing aldehydes, methods using rhodium-based catalysts and cobalt-based catalysts are known, but rhodium is more expensive than cobalt. Therefore, it is desirable to selectively and highly yield aldehydes using cobalt-based catalysts. Among cobalt-based catalysts, for example, a method using a cobalt carbonyl-based catalyst is known. This method has the advantages of a fast reaction rate and easy catalyst recovery. However, with this method, as described in Patent Document 1, there is a problem of a large amount of by-products being generated. That is, in the initial stage of the reaction, as the main product from the monoolefin, a saturated aliphatic aldehyde having one more carbon atom than the monoolefin is obtained, but this aldehyde is converted into a saturated aliphatic alcohol having one more carbon atom than the monoolefin by a hydrogenation reaction as a secondary reaction, which is the reason for the decrease in the yield and purity of the aldehyde. In addition, the alcohol reacts with the aldehyde to form by-products from acetals, resulting in a further decrease in the aldehyde yield. Therefore, it is desirable to suppress such secondary reactions and selectively and highly yield aldehydes, and thus suppressing the formation of alcohols has become a problem in the above method.

[0004] As a method for solving the above problem, Patent Document 1 discloses the following method: reacting a monoolefin, carbon monoxide, and hydrogen in the presence of a cobalt carbonyl-based catalyst, then separating unreacted olefins from the reaction product, and further reacting the unreacted olefins, carbon monoxide, and hydrogen in the presence of a cobalt catalyst and water, thereby suppressing the formation of acetals and the like. Specifically, butene dimers and the like are used as raw materials.

[0005] Patent Document 2 discloses the following method: reacting an olefin, carbon monoxide, and hydrogen in the presence of a cobalt catalyst, then separating low-boiling substances containing olefins and paraffin from the reaction product, and further reacting the unreacted olefins, carbon monoxide, and hydrogen in the presence of a cobalt catalyst, thereby suppressing side reactions. Specifically, di-n-butene and the like are used as raw materials.

[0006] In addition, Patent Document 3 discloses a method for producing the following oxygen-containing compound, that is, reacting an olefin, carbon monoxide and hydrogen in the presence of a cobalt catalyst, then separating unreacted monoolefin from the reaction product, and further reacting the unreacted monoolefin, carbon monoxide and hydrogen in the presence of a cobalt catalyst. Specifically, a co-dimer of butene isomers or the like is used as a raw material.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent No. 4368454 Gazette

[0010] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2002-53501

[0011] Patent Document 3: British Patent No. 702204 Gazette Summary of the Invention

[0012] Problems to be Solved by the Invention

[0013] However, regarding the method described in Patent Document 1, the amount of alcohol produced is large and the aldehyde selectivity is low, so it cannot meet practical requirements.

[0014] Regarding the method described in Patent Document 2, although the formation of high-boiling components such as acetals can be suppressed, the amount of alcohol produced is also large and the aldehyde selectivity is also low, so it cannot meet practical requirements.

[0015] In addition, Patent Document 3 also describes a reaction using isobutene as a raw material, but does not describe reacting unreacted isobutene with carbon monoxide and hydrogen again.

[0016] In view of the above circumstances, an object of the present invention is to provide a method for selectively producing 3,5,5-trimethylhexanal, which is useful as a raw material for carboxylic acids and the like that are raw materials for refrigeration oils and the like, in high yield.

[0017] Means for Solving the Problems

[0018] [1] A method for producing 3,5,5-trimethylhexanal, which is a method for producing 3,5,5-trimethylhexanal by reacting diisobutene (DIB) with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst, and the production method includes:

[0019] A step (first-stage reaction step) of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 to 85%;

[0020] A step (unreacted DIB separation step) of separating unreacted DIB from the reaction product obtained in the previous first-stage reaction step; and

[0021] A step (second-stage reaction step) of reacting the separated unreacted DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst.

[0022] [2] The method for producing 3,5,5-trimethylhexanal as described in [1] above, wherein in the aforementioned second-stage reaction step, the reaction temperature (°C) x and the cobalt concentration (g / kg) y relative to DIB satisfy the following formulas (1) and (2).

[0023] (1) y ≤ 8.0×10 6 e -0.09x

[0024] (2) 0.1 ≤ y ≤ 20

[0025] [3] The method for producing 3,5,5-trimethylhexanal as described in [2] above, wherein in the aforementioned second-stage reaction step, the cobalt concentration (g / kg) y relative to DIB satisfies the following (3).

[0026] (3) 0.1 ≤ y ≤ 15

[0027] [4] The method for producing 3,5,5-trimethylhexanal as described in any one of [1] - [3] above, wherein the reaction temperature in the aforementioned second-stage reaction step is 180°C or lower.

[0028] [5] The method for producing 3,5,5-trimethylhexanoic acid, which comprises a step of oxidizing 3,5,5-trimethylhexanal obtained by the production method described in any one of [1] - [4] above.

[0029] [6] A method for suppressing the formation of 3,5,5-trimethylhexanol, which is a method for suppressing the formation of 3,5,5-trimethylhexanol in the method for producing 3,5,5-trimethylhexanal by reacting diisobutene (DIB) with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst. The method for suppressing the formation of 3,5,5-trimethylhexanol includes:

[0030] A step (first-stage reaction step) of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 - 85%;

[0031] A step of separating unreacted DIB from the reactants obtained in the aforementioned first-stage reaction step (unreacted DIB separation step); and

[0032] A step of reacting the separated unreacted DIB with carbon monoxide and hydrogen at 180°C or lower in the presence of a cobalt-based catalyst (second-stage reaction step).

[0033] [7]A method for increasing the production ratio of 3,5,5-trimethylhexanal relative to 3,5,5-trimethylhexanol (3,5,5-trimethylhexanal / 3,5,5-trimethylhexanol), which is a method for increasing the production ratio of 3,5,5-trimethylhexanal relative to 3,5,5-trimethylhexanol in the method of producing 3,5,5-trimethylhexanal by reacting diisobutene (DIB) with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst.

[0034] The method for increasing the production ratio of 3,5,5-trimethylhexanal relative to 3,5,5-trimethylhexanol includes:

[0035] A step (first-stage reaction step) of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 to 85%;

[0036] A step of separating unreacted DIB from the reactants obtained in the aforementioned first-stage reaction step (unreacted DIB separation step); and

[0037] A step (second-stage reaction step) of reacting the separated unreacted DIB with carbon monoxide and hydrogen at 180°C or lower in the presence of a cobalt-based catalyst.

[0038] Effects of the Invention

[0039] According to the present invention, a method for selectively producing 3,5,5-trimethylhexanal, which is useful as a raw material for carboxylic acids and the like that are raw materials for refrigeration oils and the like, in high yield can be provided. Description of the Drawings

[0040] Figure 1 is an example of the process when implementing the production method of the present invention using an industrial continuous reaction device. Detailed Description of the Invention

[0041] Hereinafter, the mode for implementing the present invention (hereinafter, also referred to as "the present embodiment") will be described in detail. It should be noted that the present invention is not limited to the present embodiment, and various modifications can be made within the scope of its gist.

[0042] The method for producing 3,5,5-trimethylhexanal of the present embodiment is a method for producing 3,5,5-trimethylhexanal by reacting diisobutene (DIB) with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst, and the production method includes:

[0043] A step (first-stage reaction step) of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 to 85%;

[0044] ​A step of separating unreacted DIB from the reactant obtained in the aforementioned first-stage reaction step (unreacted DIB separation step); and

[0045] A step of reacting the separated unreacted DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst (second-stage reaction step).

[0046] The 3,5,5-trimethylhexanal (hereinafter, also referred to as "formyl substrate") obtained by the production method of the present embodiment can be a substance having any steric structure or a mixture thereof.

[0047] Hereinafter, the production method of the formyl substrate of the present embodiment will be described.

[0048] In the production method of the formyl substrate of the present embodiment, the formyl substrate can be produced using DIB as a raw material by a method including three steps including the two-stage reaction step described later.

[0049] (First-stage reaction step)

[0050] The first-stage reaction step in the production method of the formyl substrate of the present embodiment is a step of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 to 85%. In this step, DIB is reacted with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst (hydroformylation reaction), and the reaction is stopped at the time point when the conversion rate of DIB reaches 50 - 85%.

[0051] As the raw material DIB, a commercially available substance can be used, or it can be produced according to a known method. When produced according to a known method, for example, as described in JP-A-2013-010717, it can be produced by the following method: from the C4 fraction generated by fluid catalytic cracking (FCC) and ethylene production equipment, isobutene is selectively reacted with sulfuric acid, separated in the form of isobutyl sulfate, and then thermally cracked.

[0052] As DIB, 2,2,4-trimethyl-1-pentene (TM-1), 2,2,4-trimethyl-2-pentene (TM-2), or a mixture thereof can be used. As the mixing ratio when using both in combination, there is no particular limitation. From the viewpoint of reactivity, the TM-1 / TM-2 ratio is preferably 0.5 or more, more preferably 1.0 or more, and further preferably 2.0 or more.

[0053] In the raw material DIB, in addition to containing the above-mentioned TM-1 and TM-2, it may also contain other components such as C8 olefins by-produced from 1-butene and 2-butene contained in the raw material isobutene during the production of DIB.

[0054] In the hydroformylation reaction, a cobalt-based catalyst commonly used in the hydroformylation reaction can be used. As the cobalt-based catalyst, for example, cobalt oxides, acetylacetonates, various carboxylates, sodium salts, chlorides, carbonyl complexes, etc. can be mentioned. More specifically, Co2(CO)8, Co4(CO) 12 , Co6(CO) 16 , NaCo(CO)4, HCo(CO)4, [Co(CO)3(C5H5)]2 (wherein C5H5 represents a cyclopentadienyl group), and other carbonyl complexes of cobalt, cobalt oxide, cobalt hydroxide, cobalt acetate, cobalt 2-ethylhexanoate, etc. Among them, carbonyl complexes of cobalt and cobalt hydroxide are preferred. These cobalt-based catalysts can be used alone or in combination of two or more.

[0055] The cobalt concentration is usually 0.01 - 15 g / kg relative to DIB, preferably in the range of 0.1 - 10 g / kg, more preferably in the range of 0.3 - 5 g / kg. When the cobalt concentration relative to DIB is 15 g / kg or less, the reaction control becomes easy and the reaction tends to stop at the desired conversion rate. In addition, there is a tendency that precipitates of the catalyst are not easily generated. On the other hand, when the cobalt concentration relative to DIB is 0.01 g / kg or more, there is a tendency to suppress the decrease in the reaction rate and the reaction time required to reach the desired conversion rate becomes shorter.

[0056] The hydroformylation reaction can also be carried out without using a solvent, or a solvent can be used. As the solvent, as long as DIB and the cobalt-based catalyst can be dissolved, there is no particular limitation. Specific examples of the solvent include, for example, alcohols such as ethanol, isopropanol, butanol, 2-ethylhexanol, 2-octanol; esters such as butyl acetate, cyclohexyl acetate, dibutyl phthalate, bis(2-ethylhexyl) phthalate, diisononyl phthalate, diisodecyl phthalate, triisononyl trimellitate; saturated aliphatic hydrocarbons such as pentane, hexane, heptane, octane, isooctane, decane, dodecane, tetradecane; cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, dimethylcyclohexane, cyclooctane, cyclododecane, decalin; aromatic hydrocarbons such as benzene, toluene, xylene, alkylnaphthalene; ethers such as dibutyl ether, tetrahydrofuran; nitriles such as acetonitrile, propionitrile, etc. These solvents can be used alone or in combination of two or more.

[0057] The temperature of the hydroformylation reaction is usually 40 - 180 °C, preferably in the range of 80 - 170 °C, more preferably in the range of 100 - 160 °C. When carried out at a temperature of 40 °C or higher, the reaction rate tends to increase. On the other hand, when carried out at a temperature of 180 °C or lower, there is a tendency that the amounts of by-products such as alcohols produced by the secondary reaction of the aldehyde as the primary reaction product and acetals and ethers produced by the alcohol are reduced, and the yield of the reaction is increased.

[0058] The hydroformylation reaction is preferably carried out under pressure based on a mixed gas of carbon monoxide and hydrogen (hereinafter, also referred to as "synthesis gas"). At this time, carbon monoxide and hydrogen can be introduced into the reaction system independently of each other. Alternatively, synthesis gas can be prepared in advance and then introduced into the reaction system. The molar ratio of the synthesis gas introduced into the reaction system (=H2 / CO) is usually in the range of 0.2 to 5.0, preferably in the range of 0.5 to 2.0, and more preferably in the range of 0.7 to 1.5. It should be noted that in the reaction system, gases inert to the hydroformylation reaction, such as methane, ethane, propane, nitrogen, helium, argon, carbon dioxide, etc., can coexist.

[0059] The hydroformylation reaction is usually carried out at a pressure in the range of 0.2 - 40 MPaG, preferably at a pressure in the range of 5 - 35 MPaG, and more preferably at a pressure in the range of 10 - 30 MPaG. When carried out at a pressure of 0.2 MPaG or more, there is a tendency for the stability of the cobalt-based catalyst to increase (inhibiting the precipitation of the catalyst in the reaction system). When carried out at a pressure of 40 MPaG or less, there is a tendency to be able to suppress the initial investment of equipment.

[0060] The reaction in the first-stage reaction process is stopped at the time point when the conversion rate of DIB reaches 50 - 85%. From the viewpoint of suppressing the formation of alcohols, etc., it is preferably stopped at the time point when it reaches 50 - 80%, more preferably at the time point when it reaches 50 - 75%, and further preferably at the time point when it reaches 60 - 75%. The conversion rate of DIB is calculated from the analytical values such as gas chromatography. Specifically, it can be obtained according to the method described in the examples below.

[0061] In the first-stage reaction process, it is preferable to undergo a neutralization and water washing process after the hydroformylation reaction. In the neutralization and water washing process, for example, by adding an aqueous solution of an alkali metal compound or an alkaline earth metal compound to the system after the hydroformylation reaction, the cobalt-based catalyst can be extracted and removed. Examples of the alkali metal compound or alkaline earth metal compound include hydroxides and metal salts of lithium, sodium, potassium, magnesium, calcium, etc.

[0062] In the first-stage reaction process, the reaction form of the hydroformylation reaction is not particularly limited and can be carried out batchwise or continuously using a known reaction apparatus. As the reaction apparatus, specifically, any of a stirred reaction tank, a tower-type reaction tank, or a tubular reaction tank can be used for implementation.

[0063] (Separation process of unreacted DIB)

[0064] In the method for producing a formyl matrix according to this embodiment, a step of separating unreacted DIB from the reactant obtained in the above first-stage reaction step (unreacted DIB separation step) is performed. In this step, known purification methods can be used to separate unreacted DIB from the reaction composition obtained in the first-stage reaction step or the reaction composition after the removal treatment of the cobalt-based catalyst.

[0065] As known purification methods, for example, distillation, adsorption, chromatography, etc. can be cited. Among them, distillation is preferred because a stationary phase (the stationary phase needs to be replaced) is not required, and vacuum distillation is more preferred. The conditions in the distillation operation are not particularly limited.

[0066] In addition, the purified unreacted DIB may contain paraffin and can also be directly used as a raw material for the second-stage reaction step.

[0067] (Second-stage reaction step)

[0068] In the method for producing a formyl matrix according to this embodiment, a step of reacting unreacted DIB separated in the above unreacted DIB separation step with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst is performed (second-stage reaction step). In this step, the separated unreacted DIB is subjected to a hydroformylation reaction.

[0069] It should be noted that here, the DIB subjected to the hydroformylation reaction can be mixed with new DIB on the basis of the separated unreacted DIB. From the viewpoint of further selectively obtaining aldehyde in high yield, the amount of new DIB during mixing is preferably 75% by mass or less, more preferably 50% by mass or less, further preferably 30% by mass or less, and particularly preferably 15% by mass or less of the total amount of unreacted DIB and new DIB.

[0070] The molar ratio of the cobalt-based catalyst, solvent, and synthesis gas during the hydroformylation reaction in the second-stage reaction step can be selected in accordance with the conditions of the aforementioned first-stage reaction step.

[0071] For the same reasons as in the first-stage reaction step, the pressure during the hydroformylation reaction is usually 0.2 - 40 MPaG, preferably 5 - 35 MPaG, more preferably 10 - 30 MPaG, and further preferably 15 - 30 MPaG.

[0072] In addition, in the second-stage reaction step, it is preferred that the cobalt concentration relative to DIB during the hydroformylation reaction is 0.1 - 20 g / kg and the reaction temperature is in the range of 100 - 210 °C. Among them, more preferably, the reaction temperature (°C) x and the cobalt concentration (g / kg) y relative to DIB satisfy the following formulas (1) and (2).

[0073] (1) y ≤ 8.0×106 e -0.09x

[0074] (2) 0.1 ≤ y ≤ 20

[0075] When the reaction temperature (°C) x and the cobalt concentration (g / kg) y relative to DIB satisfy the above formulas (1) and (2), there is a tendency to suppress the formation of alcohol and obtain aldehyde in high yield.

[0076] From the viewpoints of ease of reaction control and catalyst stability, the cobalt concentration (g / kg) y relative to DIB preferably further satisfies the following formula (3).

[0077] (3) 0.1 ≤ y ≤ 15

[0078] In addition, from another perspective, in the hydroformylation reaction in the second-stage reaction process, the reaction temperature is preferably 180°C or lower, more preferably 170°C or lower, and further preferably 165°C or lower, from the viewpoint of suppressing the formation of alcohol.

[0079] In the second-stage reaction process, from the viewpoint of obtaining aldehyde in high yield, it is preferred to stop the reaction at the time point when the conversion rate of unreacted DIB reaches 60 - 100%, and more preferably at the time point when it reaches 70 - 95%.

[0080] After the second-stage reaction process is completed, it is preferred to remove the cobalt-based catalyst in the same manner as described in the first-stage reaction process above.

[0081] In the second-stage reaction process, the reaction form of the hydroformylation reaction is not particularly limited, and it can be carried out batchwise or continuously using a known reaction apparatus. As the reaction apparatus, specifically, it can be carried out using any of a stirred reaction tank, a tower-type reaction tank, or a tubular reaction tank.

[0082] The formyl matrix can be purified from the reaction composition after the first-stage reaction process, the composition containing crude aldehyde from which unreacted DIB and the like have been separated, the reaction composition obtained from the second-stage reaction process, or the reaction composition after the cobalt-based catalyst removal treatment using a known purification method. At this time, the composition from the first-stage reaction process and the composition from the second-stage reaction process can be purified separately or together. As known purification methods, for example, adsorption, extraction, neutralization and water washing, distillation, adsorption, chromatography, crystallization, etc. can be cited, and these methods can also be appropriately combined. Among them, distillation is preferred, and vacuum distillation is more preferred. The conditions in the distillation operation are not particularly limited.

[0083] Figure 1 An example of the process when the method for manufacturing the formyl matrix of the present embodiment is carried out using an industrial continuous reaction apparatus is shown.

[0084] The DIB as a raw material passes through the raw material supply pipe 1, and the mixed gas of hydrogen and carbon monoxide passes through the pipe 2 and is supplied to the first-stage reactor 3. The liquid discharged from the reactor 3 is separated in the unreacted DIB recovery device 4 into a liquid containing unreacted DIB and a liquid containing a formyl matrix. The liquid containing the formyl matrix is purified in the aldehyde purification device 5 to obtain the purified aldehyde 10.

[0085] The liquid containing unreacted DIB passes through the second-stage reaction raw material supply pipe 6, and the mixed gas of hydrogen and carbon monoxide passes through the pipe 7 and is supplied to the second-stage reactor 8. The liquid discharged from the reactor 8 is purified in the aldehyde purification device 9 to obtain the purified aldehyde 10.

[0086] The liquid discharged from the first-stage reactor 3 separates the catalyst in a catalyst separation device (not shown), and the liquid from which the catalyst has been separated can be supplied to the unreacted DIB recovery device 4. In addition, new DIB can be mixed into the liquid supplied to the second-stage reactor 8, or a catalyst can be added through a second-stage reaction catalyst addition device (not shown). Using the catalyst separation device (not shown), the catalyst is separated from the liquid discharged from the reactor 8, and the liquid from which the catalyst has been separated is supplied to the aldehyde purification device 9.

[0087] According to the method for producing a formyl matrix of the present embodiment, 3,5,5-trimethylhexanal can be selectively produced from DIB in a high yield.

[0088] The 3,5,5-trimethylhexanal obtained by the method for producing a formyl matrix of the present embodiment is useful not only as a raw material for carboxylic acids and the like that are raw materials for refrigeration oils and the like, but can also be used as a raw material for alcohols, aldols, esters, amines, and the like.

[0089] The present embodiment includes a method for suppressing the formation of 3,5,5-trimethylhexanol in a method for producing 3,5,5-trimethylhexanal by reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst, which includes:

[0090] A step (first-stage reaction step) of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 to 85%;

[0091] A step (unreacted DIB separation step) of separating unreacted DIB from the reactant obtained in the aforementioned first-stage reaction step; and

[0092] A step (second-stage reaction step) of reacting the separated unreacted DIB with carbon monoxide and hydrogen at 180°C or lower in the presence of a cobalt-based catalyst.

[0093] Further, the present embodiment includes a method for increasing the production ratio of 3,5,5-trimethylhexanal to 3,5,5-trimethylhexanol (3,5,5-trimethylhexanal / 3,5,5-trimethylhexanol) in a method for producing 3,5,5-trimethylhexanal by reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst, which comprises:

[0094] A step of reacting DIB with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of DIB reaches 50 to 85% (first-stage reaction step);

[0095] A step of separating unreacted DIB from the reactants obtained in the aforementioned first-stage reaction step (unreacted DIB separation step); and

[0096] A step of reacting the separated unreacted DIB with carbon monoxide and hydrogen at 180°C or lower in the presence of a cobalt-based catalyst (second-stage reaction step).

[0097] In the above method, the production ratio of 3,5,5-trimethylhexanal to 3,5,5-trimethylhexanol (3,5,5-trimethylhexanal / 3,5,5-trimethylhexanol) is preferably 30 or more, more preferably 40 or more, and further preferably 50 or more.

[0098] The method for producing 3,5,5-trimethylhexanoic acid according to the present embodiment is a production method including a step of oxidizing the 3,5,5-trimethylhexanal obtained above.

[0099] The 3,5,5-trimethylhexanoic acid obtained by the production method of the present embodiment can be a substance having any stereostructure or a mixture thereof.

[0100] The step of oxidizing 3,5,5-trimethylhexanal can be carried out by a usual oxidation method. For example, it can be carried out according to the method described in Japanese Patent Laid-Open No. 2001-11009 and the like.

[0101] Examples

[0102] Hereinafter, the present invention will be specifically described further by way of examples, but the present invention is not limited to the following examples.

[0103] The conversion rate of DIB, the composition of the reaction solution after the reaction, the aldehyde yield, and the alcohol yield were analyzed by gas chromatography with a hydrogen flame ionization detector.

[0104] [Gas Chromatography with Hydrogen Flame Ionization Detector]

[0105] <Determination Conditions for Purity Analysis>

[0106] · Apparatus: Gas chromatograph GC-2014 manufactured by SHIMADZU Corporation

[0107] · Chromatographic column: DB-1 manufactured by Agilent Technologies (column length: 30 m, inner diameter: 0.25 mm, film thickness: 0.25 μm)

[0108] · Temperature rising condition: After maintaining at 40 °C for 10 minutes, the temperature is raised to 320 °C at a rate of 8 °C per minute and maintained for 15 minutes.

[0109] · Temperature of the sample injection part: 320 °C

[0110] · Temperature of the detector: 330 °C

[0111] [Example 1]

[0112] (First-stage reaction process A)

[0113] 213.3 g of DIB (composition: 76% by mass of 2,2,4-trimethyl-1-pentene, 21% by mass of 2,2,4-trimethyl-2-pentene, 3% of others) dissolved with HCo(CO)4 (cobalt concentration relative to DIB: 1.0 g / kg) was charged into a 500 ml autoclave made of SUS316, and the inside of the autoclave was purged with nitrogen. Then, after purging the inside of the autoclave with a mixed gas of hydrogen and carbon monoxide (H2 / CO = 1.3), the above mixed gas was supplied so that the pressure became 16 MPaG. The autoclave was placed in an electric furnace and slowly heated. After the temperature reached 150 °C, the above mixed gas was further supplied to keep the pressure inside the autoclave constant at 20 MPaG, and the reaction was carried out for 0.8 hours. The conversion rate of DIB after the reaction was measured by gas chromatography, and the result was 74%. The composition of the reaction solution measured by gas chromatography at this time is shown in Table 1.

[0114] (Second-stage reaction process)

[0115] As the raw material for the second reaction process, an assembled liquid was prepared and used according to the assumption of recovering low-boiling components (DIB, C8 paraffin) from the reaction solution of the first-stage reaction process A by distillation purification. The composition of the assembled liquid A is shown in Table 2.

[0116] 213.3 g of the assembly liquid A in which HCo(CO)4 was dissolved (cobalt concentration relative to DIB: 10.8 g / kg) was charged into a 500-ml autoclave made of SUS316, and nitrogen replacement was performed inside the autoclave. Subsequently, after replacing the inside of the autoclave with a mixed gas of hydrogen and carbon monoxide (H2 / CO = 1.3), the above mixed gas was supplied so that the pressure became 16 MPaG. The autoclave was placed in an electric furnace and slowly heated. After the temperature reached 120°C, the above mixed gas was further supplied to keep the pressure inside the autoclave constant at 20 MPaG, and the reaction was carried out for 4 hours. Measurement was performed using gas chromatography. As a result, the conversion rate of DIB after the reaction was 90.7%, the aldehyde yield was 65.1%, and the alcohol yield was 0.9%. The total aldehyde yield in two stages was 75.8%, the alcohol yield was 1.0%, and the aldehyde / alcohol ratio was 73.8.

[0117] [Example 2]

[0118] In the second-stage reaction process, the cobalt concentration relative to DIB was made 5.3 g / kg, the reaction temperature was made 130°C, and the reaction time was made 3 hours. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out.

[0119] The conversion rate of DIB after the reaction was 90.5%, the aldehyde yield was 65.6%, and the alcohol yield was 1.5%. In addition, the total aldehyde yield in two stages was 76.0%, the alcohol yield was 1.2%, and the aldehyde / alcohol ratio was 63.8.

[0120] [Example 3]

[0121] In the second-stage reaction process, the cobalt concentration relative to DIB was made 11.1 g / kg, the reaction temperature was made 140°C, and the reaction time was made 1 hour. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 95.5%, the aldehyde yield was 67.6%, and the alcohol yield was 2.7%. In addition, the total aldehyde yield in two stages was 76.5%, the alcohol yield was 1.5%, and the aldehyde / alcohol ratio was 51.1.

[0122] [Example 4]

[0123] In the second-stage reaction process, the cobalt concentration relative to DIB was made 1.4 g / kg, the reaction temperature was made 140°C, and the reaction time was made 4 hours. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 89.3%, the aldehyde yield was 66.3%, and the alcohol yield was 1.6%. In addition, the total aldehyde yield in two stages was 76.1%, the alcohol yield was 1.2%, and the aldehyde / alcohol ratio was 62.6.

[0124] [Example 5]

[0125] In the second-stage reaction process, the cobalt concentration relative to DIB was 2.8 g / kg, the reaction temperature was 150 °C, and the reaction time was 1 hour. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 89.8%, the aldehyde yield was 66.5%, and the alcohol yield was 2.3%. In addition, the total aldehyde yield in two stages was 76.2%, the alcohol yield was 1.4%, and the aldehyde / alcohol ratio was 54.8.

[0126] [Example 6]

[0127] In the second-stage reaction process, the cobalt concentration relative to DIB was 1.3 g / kg, the reaction temperature was 150 °C, and the reaction time was 2 hours. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 90.4%, the aldehyde yield was 63.1%, and the alcohol yield was 2.1%. In addition, the total aldehyde yield in two stages was 75.3%, the alcohol yield was 1.3%, and the aldehyde / alcohol ratio was 56.2.

[0128] [Example 7]

[0129] In the second-stage reaction process, the cobalt concentration relative to DIB was 0.71 g / kg, the reaction temperature was 150 °C, and the reaction time was 4 hours. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 91.4%, the aldehyde yield was 67.1%, and the alcohol yield was 2.4%. In addition, the total aldehyde yield in two stages was 76.4%, the alcohol yield was 1.4%, and the aldehyde / alcohol ratio was 53.5.

[0130] [Example 8]

[0131] In the second-stage reaction process, the cobalt concentration relative to DIB was 1.4 g / kg, the reaction temperature was 160 °C, and the reaction time was 0.5 hour. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 86.5%, the aldehyde yield was 56.2%, and the alcohol yield was 1.5%. In addition, the total aldehyde yield in two stages was 73.5%, the alcohol yield was 1.2%, and the aldehyde / alcohol ratio was 61.0.

[0132] [Example 9]

[0133] In the second-stage reaction process, the cobalt concentration relative to DIB was 0.68 g / kg, the reaction temperature was 160 °C, and the reaction time was 2 hours. Otherwise, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 90.8%, the aldehyde yield was 64.3%, and the alcohol yield was 2.6%. In addition, the total aldehyde yield in two stages was 75.6%, the alcohol yield was 1.5%, and the aldehyde / alcohol ratio was 50.9.

[0134] [Example 10]

[0135] In the second-stage reaction process, the cobalt concentration relative to DIB was 1.4 g / kg, the reaction temperature was 170 °C, and the reaction time was 0.5 hour. Except for this, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 88.5%, the aldehyde yield was 64.0%, and the alcohol yield was 3.6%. In addition, the total aldehyde yield for the two stages was 75.6%, the alcohol yield was 1.7%, and the aldehyde / alcohol ratio was 43.6.

[0136] [Example 11]

[0137] In the second-stage reaction process, the cobalt concentration relative to DIB was 0.13 g / kg, the reaction temperature was 170 °C, and the reaction time was 5 hours. Except for this, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 89.5%, the aldehyde yield was 65.4%, and the alcohol yield was 3.3%. In addition, the total aldehyde yield for the two stages was 75.9%, the alcohol yield was 1.7%, and the aldehyde / alcohol ratio was 45.5.

[0138] [Example 12]

[0139] In the second-stage reaction process, the cobalt concentration relative to DIB was 0.41 g / kg, the reaction temperature was 180 °C, and the reaction time was 1 hour. Except for this, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 90.4%, the aldehyde yield was 57.3%, and the alcohol yield was 4.6%. In addition, the total aldehyde yield for the two stages was 73.7%, the alcohol yield was 2.0%, and the aldehyde / alcohol ratio was 36.5.

[0140] [Example 13]

[0141] In the second-stage reaction process, the cobalt concentration relative to DIB was 0.12 g / kg, the reaction temperature was 190 °C, and the reaction time was 2 hours. Except for this, the same reaction as in the second-stage reaction process of Example 1 was carried out. The conversion rate of DIB after the reaction was 88.0%, the aldehyde yield was 56.7%, and the alcohol yield was 5.8%. In addition, the total aldehyde yield for the two stages was 73.6%, the alcohol yield was 2.3%, and the aldehyde / alcohol ratio was 31.6.

[0142] [Example 14]

[0143] (First-stage reaction process B)

[0144] 213.3 g of DIB (composition: 76% by mass of 2,2,4-trimethyl-1-pentene, 21% by mass of 2,2,4-trimethyl-2-pentene, 3% by mass of others) in which HCo(CO)4 was dissolved (cobalt concentration relative to DIB: 1.0 g / kg) was charged into a 500-ml autoclave made of SUS316, and the inside of the autoclave was purged with nitrogen. Then, after purging the inside of the autoclave with a mixed gas of hydrogen and carbon monoxide (H2 / CO = 1.3), the above mixed gas was supplied so that the pressure became 16 MPaG. The autoclave was placed in an electric furnace and slowly heated. After the temperature reached 150°C, the above mixed gas was further supplied to keep the pressure inside the autoclave constant at 20 MPaG, and the reaction was carried out for 0.5 hour. Measurement was carried out by gas chromatography, and as a result, the conversion rate of DIB after the reaction was 54%. The composition of the reaction solution measured by gas chromatography at this time is shown in Table 1.

[0145] (Second-stage reaction process)

[0146] As the raw material for the second-stage reaction process, an assembled liquid was prepared and used on the assumption of recovering low-boiling components (DIB, C8 paraffin) from the reaction solution of the first-stage reaction process B by distillation purification. The composition of the assembled liquid B is shown in Table 2.

[0147] Using the assembled liquid B instead of the assembled liquid A, with the cobalt concentration relative to DIB being 1.3 g / kg, the reaction temperature being 150°C, and the reaction time being 2 hours, the same reaction as in the second-stage reaction process of Example 1 was carried out except for these. The conversion rate of DIB after the reaction was 91.5%, the aldehyde yield was 67.0%, and the alcohol yield was 2.3%. In addition, the total aldehyde yield for the two stages was 72.5%, the alcohol yield was 1.3%, and the aldehyde / alcohol ratio was 54.9.

[0148] [Table 1]

[0149]

[0150] 1) The numbers in the table are in mass%,

[0151] 2) TM-1: 2,2,4-trimethyl-1-pentene,

[0152] 3) TM-2: 2,2,4-trimethyl-2-pentene

[0153] [Table 2]

[0154]

[0155] 1) The numbers in the table are in mass%,

[0156] 2) TM-1: 2,2,4-trimethyl-1-pentene

[0157] 3) TM-2: 2,2,4-Trimethyl-2-pentene

[0158] [Comparative Example 1 (one-step method)]

[0159] 430.0 g of DIB (composition: 76% by mass of 2,2,4-trimethyl-1-pentene, 21% by mass of 2,2,4-trimethyl-2-pentene, 3% by mass of others) in which HCo(CO)4 was dissolved (cobalt concentration relative to DIB: 2.1 g / kg) was charged into a 1000 ml autoclave made of SUS316, and the inside of the autoclave was purged with nitrogen. Then, after purging the inside of the autoclave with a mixed gas of hydrogen and carbon monoxide (H2 / CO = 1.1), the above mixed gas was supplied so that the pressure became 16 MPaG. The autoclave was placed in an electric furnace and slowly heated. After the temperature reached 145°C, the above mixed gas was further supplied to keep the pressure inside the autoclave constant at 20 MPaG. At the time point of 2 hours of reaction, the conversion rate was 96.9%. In addition, at this time, the aldehyde yield was 65.7%, the alcohol yield was 2.5%, and the aldehyde / alcohol ratio was 26.8.

[0160] The total compositions of Examples 1-14 and Comparative Example 1 are shown in Tables 3 and 4. The total composition of the examples represents the total composition of the reaction compositions obtained from the first-stage reaction step and the second-stage reaction step.

[0161] [Table 3]

[0162]

[0163] 1) The numbers of the total compositions in the table are in mass%.

[0164] [Table 4]

[0165]

[0166] 1) The numbers of the total compositions in the table are in mass%.

[0167] From the above results, it can be seen that the production method of the present invention is a method capable of selectively producing 3,5,5-trimethylhexanal with a high aldehyde yield, a high aldehyde / alcohol ratio, that is, it is not easy to generate alcohol as an impurity and has a high aldehyde selectivity.

[0168] [Example 15]

[0169] After manufacturing in the same manner as in Example 1 and performing distillation purification, 840.1 g of the obtained aldehyde was charged into a 2 L glass flask, and the inside of the system was purged with oxygen. Then, oxygen was supplied from a sprayer at 280 mL / min. The glass flask was slowly heated, and after the temperature reached 60°C, the reaction was carried out for 7 hours. Measurement was performed by gas chromatography, and as a result, the yield of 3,5,5-trimethylhexanoic acid was 92%.

[0170] This application is based on Japanese Patent Application No. 2020-201432 filed on December 4, 2020, the content of which is incorporated herein by reference.

[0171] Industrial Applicability

[0172] According to the present invention, it is possible to provide a method for selectively producing 3,5,5-trimethylhexanal, which is useful as a raw material for carboxylic acids and the like that are raw materials for refrigeration oils and the like, in a high yield.

[0173] Explanation of Reference Numerals

[0174] 1: Raw material supply pipe

[0175] 2: Mixed gas supply pipe for hydrogen and carbon monoxide

[0176] 3: First-stage reactor

[0177] 4: Unreacted DIB recovery device

[0178] 5: Aldehyde purification device

[0179] 6: Second-stage reaction raw material supply pipe

[0180] 7: Mixed gas supply pipe for hydrogen and carbon monoxide

[0181] 8: Second-stage reactor

[0182] 9: Aldehyde purification device

[0183] 10: Purified aldehyde

Claims

1. A process for producing 3,5,5-trimethylhexanal, which comprises reacting diisobutene with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst to produce 3,5,5-trimethylhexanal, and the production process includes: A first-stage reaction step, i.e., a step of reacting diisobutene with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of diisobutene reaches 50-85%; A step of separating unreacted diisobutene, i.e., a step of separating unreacted diisobutene from the reaction product obtained in the first-stage reaction step; and A second-stage reaction step, i.e., a step of reacting the separated unreacted diisobutene with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst, wherein, in the second-stage reaction step, the reaction temperature x and the cobalt concentration y relative to diisobutene satisfy the following formulas (1) and (2), the unit of the reaction temperature x is °C, and the unit of the cobalt concentration y relative to diisobutene is g / kg, (1)y≤8.0×10 6 e -0.09x (2)0.1≤y≤20。 2. The manufacturing method of 3,5,5-trimethylhexanal according to claim 1, wherein, in the second-stage reaction step, the cobalt concentration y relative to diisobutene satisfies the following (3), the unit of the cobalt concentration y relative to diisobutene is g / kg, (3)0.1≤y≤15。 3. The method for producing 3,5,5-trimethylhexanal according to claim 1 or 2, wherein, the reaction temperature in the second-stage reaction step is 180 °C or lower.

4. Process for producing 3,5,5-trimethylhexanoic acid, comprising: A step of producing 3,5,5-trimethylhexanal by using the production process according to any one of claims 1-3; and a step of oxidizing the obtained 3,5,5-trimethylhexanal.

5. A method for increasing the production ratio of 3,5,5-trimethylhexanal to 3,5,5-trimethylhexanol, i.e., 3,5,5-trimethylhexanal / 3,5,5-trimethylhexanol, which is a method for increasing the production ratio of 3,5,5-trimethylhexanal to 3,5,5-trimethylhexanol in a process for producing 3,5,5-trimethylhexanal by reacting diisobutene with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst, the method for increasing the production ratio of 3,5,5-trimethylhexanal to 3,5,5-trimethylhexanol includes: A first-stage reaction step, i.e., a step of reacting diisobutene with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst until the conversion rate of diisobutene reaches 50-85%; A step of separating unreacted diisobutene, i.e., a step of separating unreacted diisobutene from the reaction product obtained in the first-stage reaction step; and A second-stage reaction step, i.e., a step of reacting the separated unreacted diisobutene with carbon monoxide and hydrogen in the presence of a cobalt-based catalyst at 180 °C or lower, wherein, in the second-stage reaction step, the reaction temperature x and the cobalt concentration y relative to diisobutene satisfy the following formulas (1) and (2), the unit of the reaction temperature x is °C, and the unit of the cobalt concentration y relative to diisobutene is g / kg, (1)y≤8.0×10 6 e -0.09x (2)0.1≤y≤20。

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