Method for producing dimethanol compounds having a norbornane skeleton

Abstract

A method for producing a desired compound represented by formula (1), the method comprising a step (A) for subjecting a mixed solution containing a starting compound represented by formula (2) and a solvent to hydrogenation reduction in the presence of a catalyst having a hydrogenating ability, in which water is removed from a reaction system in the step (A). (In formula (1), R represents H, CH3, or C2H5.) (In formula (2), R represents H, CH3, or C2H5; and R1 represents CH3, C2H5, C3H7, or C4H9.)

Description

[Technical Field]

[0001] The present invention relates to a method for producing a dimethanol compound having a norbornane skeleton. [Background technology]

[0002] Dimethanol compounds having a norbornane skeleton are known to exhibit excellent characteristics when used as adhesives or resin raw materials. For example, Patent Document 1 describes a method for producing a dimethanol compound having a norbornane skeleton by hydrogenating a corresponding ester compound. Many methods for producing aliphatic alcohols by hydrogenating aliphatic ester compounds have been proposed since the 1930s. For example, copper-based catalysts containing copper oxide are known as catalysts used in hydrogenation reactions. The hydrogenation reaction can be carried out by reacting an ester compound with hydrogen gas in the presence of such a catalyst. The activation conditions for these catalysts are determined taking into account the type of use, the method of use, the reaction system, etc. For example, when a fixed-bed reaction system is used, a gas-phase reduction method is adopted for the reductive activation of a molded catalyst. Patent Document 2 states that, to avoid local overheating due to rapid catalyst reduction, it is desirable to carefully perform the catalytic reduction at a predetermined temperature in the flow of an inert gas with a hydrogen concentration of several percent to several tens of percent. On the other hand, when a suspension bed reaction method is adopted, the catalyst is in the form of a powder, and Patent Document 3 states that when activating the catalyst, either a gas phase reduction method or a liquid phase reduction method carried out in a solvent such as a hydrocarbon may be used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 147242 [Patent Document 2] Japanese Patent Application Laid-Open No. 61-161146 [Patent Document 3] Japanese Patent Application Publication No. 1-305042 Summary of the Invention [Problem to be solved by the invention]

[0004] When a hydrogenation reaction is carried out using a fixed-bed reaction method, as in Patent Document 2, it is said that the time required for catalyst reduction is as long as 4 to 14 days, which poses a problem in the productivity of aliphatic alcohols. Furthermore, there is a concern that ester compounds may be contaminated into the reaction solution when operation is disrupted or catalyst activity decreases. In particular, when the target compound is a dimethanol compound having a norbornane skeleton, both the target compound and its intermediate have high viscosity and high boiling points, making separation by simple distillation or thin-film distillation difficult. Meanwhile, using a high number of distillation stages to separate the target compound (dimethanol compound) reduces the yield, leaving room for improvement from an economic perspective. Furthermore, as in Patent Document 3, when a hydrogenation reaction is carried out by employing a suspended bed reaction method, it is said that extremely high activity is exhibited even under reaction conditions of low temperature and low pressure by using a catalyst of copper oxide and zinc oxide. However, even with this technique, there is a concern that a large amount of intermediates may be mixed into the target compound, and as mentioned above, it is not easy to separate them.

[0005] Furthermore, Patent Document 1 describes a one-pot reaction in which an ester compound as a substrate, a solvent, and a catalyst are charged, followed by catalyst activation and hydrogenation. The reaction conditions are mild: a reaction temperature of 215°C, a reaction pressure of 10 MPa, and a reaction time of 8 hours. However, the inventors' investigations have revealed that the resulting reaction solution contains a significant amount of intermediates. Furthermore, if the target compound produced is used as a polymer raw material in a state where the intermediates are entrained in the amount described above, the intermediates tend to inhibit the reaction into a polymer. Therefore, as in Patent Document 2, a large number of distillation purification stages are required to separate the target compound from the intermediates, which reduces the yield and leaves room for improvement from an economic perspective. It is possible to increase the purity of the target compound by extending the reaction time or by discarding the low-molecular-weight alcohol produced as a by-product by ester hydrogenolysis together with hydrogen gas in order to increase the hydrogen gas concentration in the gas phase; however, this is hardly an optimal production method in terms of productivity, loss of hydrogen gas, etc.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for producing a dimethanol compound having a norbornane skeleton, which can efficiently carry out a hydrogenation reaction and reduce the amount of intermediates mixed in.

[0007] The present inventors have found that the above-mentioned problems can be solved by removing water, which is by-produced during a hydrogenation reaction, from the reaction system in the production of a dimethanol compound having a norbornane skeleton, and have completed the present invention.

[0008] That is, the present invention is as follows. [1] A method for producing a target compound represented by the following formula (1): The method includes a step (A) of subjecting a mixed liquid containing a raw material compound represented by the following formula (2) and a solvent to hydrogenation reduction in the presence of a catalyst having hydrogenation ability, The production method, wherein water is removed from the reaction system in the step (A). [ka] (In the formula (1), R represents H, CH, or C H ). [ka] (In the formula (2), R represents H, CH, or C H . R represents CH, C H, C H , or C H .) [2] The method according to [1], wherein the water content of the mixture measured after the removal of the water is 4500 ppm or less. [3] The production method according to [1] or [2], wherein in the step (A), the catalyst is activated at a first temperature and a first pressure, and after the activation, the raw material compound is hydrogenated at a second temperature and a second pressure. [4] The method according to [3], wherein the water is removed before the hydrogenation. [5] the first temperature and the first pressure are 100°C or higher and 170°C or lower and 0.5 MPa or higher and 5 MPa or lower, respectively; The manufacturing method according to [3] or [4], wherein the second temperature and the second pressure are higher than 170°C and lower than 250°C and higher than 5 MPa and lower than 20 MPa, respectively. [6] The production method according to any one of [1] to [5], wherein the content of the intermediate represented by the following formula (3) in the target compound is 0.5 mass % or less: [ka] (In the formula (3), R, R1, and n have the same meanings as in the formula (2).) [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for producing a dimethanol compound having a norbornane skeleton, which can efficiently carry out a hydrogenation reaction and reduce the amount of intermediates mixed in. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a mode for carrying out the present invention (hereinafter also referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist. In addition, in this specification, "to" means that the numerical values ​​on both ends thereof are included as upper and lower limits, unless otherwise specified.

[0011] <Method of producing a dimethanol compound having a norbornane skeleton> The production method of this embodiment is a method for producing a target compound represented by the following formula (1) (i.e., a dimethanol compound having a norbornane skeleton represented by the above formula (1); hereinafter, also simply referred to as "target compound"), and includes a step (A) of subjecting a mixed liquid containing a raw material compound represented by the following formula (2) and a solvent to hydrogenation reduction in the presence of a catalyst having hydrogenation ability, and in the step (A), water is removed from the reaction system. [ka] (In the formula (1), R represents H, CH, or C H ). [ka] (In the formula (2), R represents H, CH, or C H . R represents CH, C H, C H , or C H .)

[0012] The production method of this embodiment is configured as described above, and therefore, when producing the target compound, the hydrogenation reaction can be carried out efficiently and the amount of intermediates mixed in can be reduced. Such target compound can be preferably used as a paint additive, adhesive, resin raw material, etc.

[0013] The synthetic route for producing the target compound is not limited to the following, but for example, a synthetic route shown in the following formula (I) can be adopted using dicyclopentadiene or cyclopentadiene and an olefin having a functional group as raw materials. [ka] (In the above formula (I), R in formulas (1) to (4) represents H, CH3, or C2H5. R1 in formulas (1) to (3) represents CH3, C2H5, C3H7, or C4H9.)

[0014] Formula (3) in the above formula (I) represents a synthetic intermediate that can accompany the target compound. Hereinafter, for the sake of convenience, this synthetic intermediate will also be referred to simply as "intermediate."

[0015] [Monoolefin having 14 to 19 carbon atoms represented by formula (4)] In this embodiment, the monoolefin having 14 to 19 carbon atoms and represented by the following formula (4) can be produced by carrying out a Diels-Alder reaction between an olefin having a functional group and dicyclopentadiene. [ka] (In formula (4), R represents H, CH3, or C2H5. R1 represents CH3, C2H5, C3H7, or C4H9.)

[0016] Examples of the olefin having a functional group used in the Diels-Alder reaction include, but are not limited to, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate, and among these, methyl methacrylate, ethyl methacrylate, methyl acrylate, and ethyl acrylate are preferred.

[0017] The dicyclopentadiene used in the Diels-Alder reaction of this embodiment is preferably high-purity, and the content of impurities such as butadiene and isoprene is preferably low. The purity of dicyclopentadiene is preferably 90% or higher, more preferably 95% or higher. It is also known that dicyclopentadiene depolymerizes to cyclopentadiene (so-called monocyclopentadiene) under heating conditions, so cyclopentadiene can be used instead of dicyclopentadiene. It is believed that the monoolefin having 14 to 19 carbon atoms represented by the above formula (4) is essentially produced via a monoolefin having 9 to 14 carbon atoms represented by the following formula (5) (first-stage Diels-Alder reaction product). The produced monoolefin represented by the following formula (5) is then subjected to a Diels-Alder reaction (second-stage Diels-Alder reaction) with cyclopentadiene (diene) present in the reaction system as a new dienophile, thereby producing the monoolefin having 14 to 19 carbon atoms represented by the above formula (4). [ka] (In formula (5), R represents H, CH3, or C2H5. R1 represents CH3, C2H5, C3H7, or C4H9.)

[0018] The presence of cyclopentadiene in the reaction system tends to promote efficient progress of the two-stage Diels-Alder reaction, so the reaction temperature for the Diels-Alder reaction is preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 130°C or higher. On the other hand, in order to suppress the by-production of high-boiling substances, the reaction is preferably carried out at a temperature of 250°C or lower. Furthermore, hydrocarbons, alcohols, esters, and the like can also be used as reaction solvents, and preferred examples include aliphatic hydrocarbons having 6 or more carbon atoms, cyclohexane, toluene, xylene, ethylbenzene, mesitylene, propanol, and butanol.

[0019] The Diels-Alder reaction can be carried out in a variety of reaction systems, including a batch system using a tank reactor or the like, a semi-batch system in which a substrate or a substrate solution is supplied to a tank reactor under reaction conditions, and a continuous flow system in which substrates are passed through a tubular reactor under reaction conditions.

[0020] The reaction product obtained by the Diels-Alder reaction (monoolefin having 14 to 19 carbon atoms and represented by the above formula (4)) can be used as it is as a raw material for the subsequent hydroformylation reaction, or it may be purified by a method such as distillation, extraction, or crystallization and then subjected to the subsequent step. Note that the monoolefin having 14 to 19 carbon atoms and represented by the above formula (4) is not limited to those synthesized as described above, and any commercially available product may be used in the production method of this embodiment.

[0021] [Starting compound represented by formula (2)] The raw material compound represented by formula (2) in formula (I) above can be produced, for example, by hydroformylating a monoolefin having 14 to 19 carbon atoms represented by formula (4) with carbon monoxide and hydrogen gas in the presence of a rhodium compound and an organophosphorus compound.

[0022] The rhodium compound used in the hydroformylation reaction is not particularly limited, and examples thereof include compounds that form complexes with organophosphorus compounds and exhibit hydroformylation activity in the presence of carbon monoxide and hydrogen, such as rhodium acetylacetonate dicarbonyl (hereinafter also referred to as "Rh(acac)(CO)"), RhO, and Rh(CO). 12 , Rh6(CO) 16 Alternatively, a catalyst precursor such as Rh(NO3)3 may be introduced into the reaction mixture together with the organophosphorus compound to form a catalytically active rhodium-metal hydride carbonyl phosphorus complex in the reaction vessel, or a rhodium-metal hydride carbonyl phosphorus complex may be prepared in advance and introduced into the reactor. In this embodiment, it is preferable to react Rh(acac)(CO)2 with the organophosphorus compound in the presence of a solvent, and then introduce the resulting catalytically active rhodium-organophosphorus complex into the reactor together with an excess of the organophosphorus compound, and use it in the hydroformylation reaction.

[0023] The amount of the rhodium compound used in the hydroformylation reaction is preferably 0.1 to 60 micromoles, more preferably 0.1 to 30 micromoles, even more preferably 0.2 to 20 micromoles, and even more preferably 0.5 to 10 micromoles, per mole of the monoolefin having 14 to 19 carbon atoms and represented by formula (4), which is the substrate of the hydroformylation reaction. By using an amount of the rhodium compound that is less than 60 micromoles per mole of the monoolefin having 14 to 19 carbon atoms, it is possible to reduce the cost of the rhodium catalyst without installing a recovery and recycling facility for the rhodium complex, thereby reducing the economic burden associated with the recovery and recycling facility.

[0024] In the above hydroformylation reaction, the organophosphorus compound that forms a catalyst for the hydroformylation reaction together with the rhodium compound includes a phosphine represented by the general formula P(-R1)(-R2)(-R3) or a phosphite represented by the general formula P(-OR1)(-OR2)(-OR3). Specific examples of R1, R2, and R3 in the above general formula include an aryl group that may be substituted with an alkyl or alkoxy group having 1 to 4 carbon atoms, and an alicyclic alkyl group that may be substituted with an alkyl or alkoxy group having 1 to 4 carbon atoms. Triphenylphosphine and triphenylphosphite are preferred. The amount of the organophosphorus compound used is preferably 300 to 10,000 times, more preferably 500 to 10,000 times, even more preferably 700 to 5,000 times, and even more preferably 900 to 2,000 times the molar amount of rhodium atoms in the rhodium compound. When the amount of the organophosphorus compound used is 300 times or more the moles of rhodium atoms, the rhodium metal hydride carbonyl phosphorus complex as the catalytic active material tends to contribute to stability, resulting in an improvement in reaction efficiency. On the other hand, when the amount of the organophosphorus compound used is 10,000 times or less the moles of rhodium atoms, economic efficiency tends to improve in terms of the cost of the organophosphorus compound.

[0025] The hydroformylation reaction can be carried out without using a solvent, but is preferably carried out using a solvent inert to the reaction. The solvent is not particularly limited as long as it dissolves the monoolefin having 14 to 19 carbon atoms represented by formula (3), dicyclopentadiene or cyclopentadiene, the rhodium compound, and the organophosphorus compound. Specific examples include hydrocarbons such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons; esters such as aliphatic esters, alicyclic esters, and aromatic esters; alcohols such as aliphatic alcohols and alicyclic alcohols; and aromatic halides. Among these, hydrocarbons are preferred, and among these hydrocarbons, alicyclic hydrocarbons and aromatic hydrocarbons are preferred.

[0026] The temperature when carrying out the hydroformylation reaction is preferably 40°C to 160°C, more preferably 80°C to 140°C. When the reaction temperature is 40°C or higher, a sufficient reaction rate can be obtained and the amount of residual monoolefin starting material can be reduced. Furthermore, by keeping the reaction temperature at 160°C or lower, the generation of by-products derived from the monoolefin starting material and the reaction product can be reduced, and a decrease in reaction performance can be prevented.

[0027] The hydroformylation reaction is carried out under pressure with carbon monoxide (hereinafter also referred to as "CO") and hydrogen (hereinafter also referred to as "H2") gases. CO and H2 gases can be introduced into the reaction system independently, or they can be introduced into the reaction system as a pre-prepared mixed gas. The molar ratio of CO and H2 gases introduced into the reaction system (=CO / H2) is preferably 0.2 to 5, more preferably 0.5 to 2, and even more preferably 0.8 to 1.2. When the molar ratio of CO and H2 gases is within the above range, the reaction activity of the hydroformylation reaction and the selectivity for the target aldehyde tend to be improved. Note that the CO and H2 gases introduced into the reaction system decrease as the reaction progresses, so the use of a pre-prepared mixed gas of CO and H2 may simplify reaction control.

[0028] The reaction pressure of the hydroformylation reaction is preferably 1 to 12 MPa, more preferably 1.2 to 8 MPa, and even more preferably 1.5 to 5 MPa. A reaction pressure of 1 MPa or higher tends to facilitate a sufficient reaction rate and reduce the amount of residual monoolefins (the starting material). Furthermore, a reaction pressure of 12 MPa or lower tends to be economically advantageous because it eliminates the need for expensive equipment with excellent pressure resistance. In particular, when the reaction is carried out in a batch or semi-batch system, CO and H gas are discharged and the pressure is reduced after the reaction is complete, and therefore, the lower the pressure, the less CO and H gas are lost, which tends to be economically advantageous.

[0029] The hydroformylation reaction is preferably carried out as a batch or semi-batch reaction. The semi-batch reaction can be carried out by adding the rhodium compound, the organophosphorus compound, and the solvent to a reactor, pressurizing the reactor with CO / H gas, heating the reactor, and then adjusting the reaction conditions as described above, and then feeding the raw material monoolefin or a solution thereof to the reactor.

[0030] The reaction product obtained in the hydroformylation reaction can be used as it is as a raw material for the subsequent reduction reaction, or it may be purified, for example, by distillation, extraction, crystallization, etc., and then subjected to the subsequent step. The raw material compound represented by formula (2) is not limited to those synthesized as described above, and any commercially available product may be used in the production method of this embodiment.

[0031] [Process (A)] The production method of this embodiment includes step (A) of subjecting a mixed solution containing a raw material compound represented by formula (2) and a solvent to hydrogenation reduction in the presence of a catalyst having hydrogenation ability (hereinafter also referred to as a "hydrogenation catalyst"). In this embodiment, by removing water from the reaction system in step (A), not only is the target compound obtained from the raw material compound, but the amount of intermediates mixed into the target compound is reduced. This is presumably due to the following reason, but the mechanism of action of this embodiment is not limited to this reasoning. That is, water is by-produced in the reaction system of step (A), and it is thought that this water deactivates the activated hydrogenation catalyst. In this embodiment, it is thought that removing water makes it easier to maintain the activity of the hydrogenation catalyst, resulting in sufficient reaction progress and reduced intermediates mixed in.

[0032] The hydrogenation catalyst used in step (A) is, but is not limited to, a catalyst containing at least one element selected from the group consisting of copper, chromium, iron, zinc, and aluminum. Among these, copper-based catalysts such as Cu-Cr catalysts, Cu-Zn catalysts, Cu-Zn-Al catalysts, and Cu-Fe-Al catalysts are preferred, and Cu-Cr catalysts and Cu-Zn-Al catalysts are more preferred. The hydrogenation catalysts described above can be commercially available, and examples thereof include E-01X (Cu-Zn-Al catalyst; copper oxide content: 46%, zinc oxide content: 46%, aluminum oxide content: 5%) and N-203S (copper oxide content: 46.1%, chromium oxide content: 43.8%, manganese oxide content: 4.2%) manufactured by JGC Catalysts and Chemicals Co., Ltd.

[0033] The amount of the hydrogenation catalyst used is not particularly limited, but is preferably 1 to 50% by mass relative to the substrate, i.e., the raw material compound represented by formula (2). When the amount of the hydrogenation catalyst used is 1% by mass or more, the reaction proceeds sufficiently, and as a result, the yield of the target product tends to be improved. Furthermore, even if the amount of the hydrogenation catalyst used exceeds 50% by mass, the effect of improving the reaction rate commensurate with the amount of catalyst used in the reaction tends not to be obtained, so from an economical point of view, it is preferable to keep the amount used at 50% by mass or less. In other words, by setting the amount of the hydrogenation catalyst used within the above-mentioned range, the hydrogenation reaction tends to be carried out efficiently. From the above viewpoint, the amount of the hydrogenation catalyst used is more preferably 2 to 20% by mass, and even more preferably 5 to 10% by mass.

[0034] In step (A), a solvent is used. Examples of the solvent include, but are not limited to, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and alcohols. Among these, it is preferable to use alicyclic hydrocarbons, aromatic hydrocarbons, and alcohols as the solvent. Specific examples of preferable solvents include cyclohexane, toluene, xylene, methanol, ethanol, 1-propanol, cyclohexanol, and 2-octanol.

[0035] In this embodiment, from the viewpoint of further reducing the amount of intermediates mixed in, the water content of the mixed liquid measured after removing water is preferably 4500 ppm or less, more preferably 4000 ppm or less, and even more preferably 3000 ppm or less. The water content can be measured based on the method described in the Examples below. In addition, when a copper-based catalyst is used as the hydrogenation catalyst, the amount of water produced as a by-product in the reaction system can be predicted from the amount of copper oxide in the catalyst. That is, the theoretical amount of water can be predicted based on the following formula: Water content = catalyst amount (g) × copper oxide content (mass%) / 100 × 18.015 (water molecular weight) / 79.545 (copper oxide molecular weight) Based on such a predicted value, it is preferable to adjust the amount of water to be removed so that the water content of the mixed liquid falls within the above-mentioned range.

[0036] In this embodiment, from the viewpoint of further increasing the reaction efficiency, it is preferable to activate the catalyst at a first temperature and a first pressure in step (A), and then, after the activation, hydrogenate the raw material compound at a second temperature and a second pressure. As described above, since by-produced water is thought to deactivate the activated hydrogenation catalyst, it is preferable to remove water before hydrogenation.

[0037] Activation of the hydrogenation catalyst is an operation for reducing the hydrogenation catalyst and can be carried out at a first temperature and a first pressure. In this embodiment, the first temperature is preferably 100°C or higher and 170°C or lower. When the first temperature is 170°C or lower, the occurrence of side reactions and decomposition reactions tends to be suppressed. Furthermore, when the first temperature is 100°C or higher, the reduction reaction of the catalyst tends to be completed within an appropriate time. From the same viewpoint, the first temperature is more preferably 120°C or higher and 170°C or lower. In this embodiment, the first pressure is preferably 0.5 MPa or more and 5 MPa or less. When the first pressure is 0.5 MPa or more, a sufficient reaction rate tends to be obtained, and when it is 5 MPa or less, the loss of H gas during water removal tends to be small, which tends to be economically advantageous. From the same viewpoint, the first pressure is more preferably 1 MPa or more and 3 MPa or less, and even more preferably 1.5 MPa or more and 2 MPa or less. In this embodiment, the reaction time for activating the hydrogenation catalyst is preferably 0.2 hours or more and 3 hours or less. When the first reaction time is 0.2 hours or more, the reduction state of the catalyst tends to be better, and when the first reaction time is 3 hours or less, the reaction time tends to be reduced while the reduction reaction of the catalyst proceeds sufficiently.

[0038] Although activation of the hydrogenation catalyst may be performed in the absence of the raw material compound, in this embodiment, activation is preferably performed in the presence of the raw material compound from the viewpoint of reaction efficiency. When activation of the hydrogenation catalyst is performed in the presence of the raw material compound, water is by-produced as reduced water. The procedure for removing such water is not particularly limited, but may include, for example, purging the gas phase several times to remove water present in the gas phase from the reaction system, or installing a nozzle line in the mixed solution in advance and bubbling inert gas such as H2 gas or N2 to remove water from the reaction system. To determine whether the treatment is complete, a trap may be installed at the end of the exhaust gas and the operation may be continued until the amount of water reaches 2 to 3 times the expected amount, or the moisture content of the reaction solution may be measured.

[0039] The hydrogenation of the starting compound is an operation to obtain the target compound and can be carried out at a second temperature and a second pressure. In this embodiment, the second temperature is preferably higher than 170°C and not higher than 250°C. When the second temperature is not higher than 250°C, the occurrence of side reactions and decomposition reactions tends to be suppressed, and the target compound tends to be obtained in a high yield. Furthermore, when the second temperature is higher than 170°C, the reaction tends to be completed within a reasonable time, and a decrease in productivity and a decrease in the yield of the target product tend to be avoided. From the same viewpoint, the second temperature is more preferably not lower than 190°C and not higher than 230°C. In this embodiment, the second pressure is preferably greater than 5 MPa and equal to or less than 20 MPa. When the second pressure is equal to or less than 20 MPa, the occurrence of side reactions and decomposition reactions tends to be suppressed, and the target compound tends to be obtained in a high yield. Furthermore, when the second pressure is greater than 5 MPa, the reaction tends to be completed within a reasonable time. From the same viewpoint, the second pressure is more preferably greater than 5 MPa and equal to or less than 15 MPa, and even more preferably greater than 5 MPa and equal to or less than 12 MPa. In the hydrogenation in this embodiment, a gas inert to the hydrogenation reaction (for example, nitrogen or argon) may be present. The pressures mentioned above refer to values ​​as hydrogen partial pressures.

[0040] In this embodiment, from the viewpoint of the physical properties obtained when the target compound is further processed, the content of the intermediate represented by the above formula (3) in the target compound obtained in step (A) in this embodiment is preferably 0.5 mass% or less. The content of the intermediate can be measured based on the method described in the Examples below. Furthermore, the content of the intermediate can be adjusted to the above range by adjusting the amount of water removed in step (A). The target compound obtained in step (A) of this embodiment can be purified by, for example, distillation, extraction, crystallization, or the like. [Example]

[0041] The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to these examples.

[0042] <Analysis method> (1) Gas chromatographic analysis conditions Analytical equipment: Shimadzu Corporation capillary gas chromatograph GC-2010 Plus Analytical column 1: GL Sciences, InertCap1 (30 m, 0.32 mm I.D., film thickness 0.25 μm) Oven temperature 1: 60°C (0.5 min) - 15°C / min - 280°C (4 min) Detector 1: FID, temperature 280℃ Internal standard: paraxylene Analytical column 2: GL Sciences, InertCapWAX (30 m, 0.32 mm I.D., film thickness 0.25 μm) Oven temperature 2: 60°C (0.5 min) - 20°C / min - 250°C (20 min) Detector 2: FID, temperature 250℃ (2)GC-MS measurement conditions Analytical equipment: Shimadzu Corporation, GCMS-QP2010 Plus Ionization voltage: 70V Analytical column: Agilent Technologies, DB-1 (30 m, 0.32 mm I.D., film thickness 1.00 μm) Oven temperature: 60°C (0.5 min) - 15°C / min - 280°C (4 min) (3) Moisture measurement conditions Analytical equipment: Metrohm Coulometric KF Moisture Analyzer 899 Coulometer (4) Weight average molecular weight Using gel permeation chromatography (GPC), a calibration curve was prepared using tetrahydrofuran as a developing solvent and standard polystyrene of known molecular weight (molecular weight distribution = 1). Calculations were made from the GPC retention time based on this calibration curve. Specifically, the GPC measurement was carried out under the following conditions: Apparatus: Tosoh Corporation, HLC-8320GPC Column; Guard column: TSKguardcolumn SuperMPHZ-M x 1 Analytical column: TSKgel SuperMultiporeHZ-M x 3 Solvent: tetrahydrofuran Injection volume: 10μL Sample concentration: 0.2 w / v% tetrahydrofuran solution Solvent flow rate: 0.35 ml / min Measurement temperature: 40℃ Detector: RI (5) Glass transition temperature Measurement was performed using a differential scanning calorimeter (DSC) using a DSC7000X manufactured by Hitachi High-Tech Science Corporation at a temperature rise and fall rate of 10°C / min.

[0043] Example 1 The target compound was synthesized according to the route shown in formula (Ia) below. [ka]

[0044] (Obtaining monoolefins) A 500 mL stainless steel reactor was charged with 215 g (2.50 mol) of methyl acrylate and 165 g (1.25 mol) of dicyclopentadiene, and the reaction was carried out for 2 hours at 220 °C. A reaction liquid containing 152 g of the monoolefin represented by formula (4a) was obtained and purified by distillation, and a portion was then subjected to the subsequent reaction.

[0045] (Obtaining aldehydes) The hydroformylation reaction of the monoolefin represented by formula (4a) was carried out in a 500 mL stainless steel reactor. The reactor was charged with 100 g of the distilled and purified monoolefin represented by formula (4a), 96 g of 2-octanol (Kokura Synthetic Industries), 213 mg of triphenyl phosphite (Wako Pure Chemical Industries, Ltd.) (1500 mol ppm relative to the monoolefin), and 355 μg of Rh(acac)(CO)2 (N.E. Chemcat Corporation) (3 mol ppm relative to the monoolefin). The atmosphere in the reactor was replaced with nitrogen and a CO / H2 mixed gas three times each, after which the system was pressurized with a CO / H2 mixed gas and the reaction was carried out at 100 °C and 2 MPa for 3 hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography and GC-MS. As a result, it was found that the reaction solution contained 112.6 g of the raw material compound represented by formula (2a) having a molecular weight of 248 as the main product (substrate conversion rate 100% (= (charged monoolefin - remaining charged monoolefin) / charged monoolefin) × 100%), and the aldehyde yield was 99.5% (= main product / charged monoolefin × 100%). Next, the raw material compound represented by formula (2a) was purified by distillation, and a portion thereof was subjected to the subsequent reaction.

[0046] (reduction of catalyst and dehydration of reduced water) A 300 mL stainless steel reactor equipped with a nitrogen bubbling nozzle was charged with 91.6 g of the distilled and purified starting compound represented by formula (2a), 15.0 g of Cu-Zn-Al catalyst (E-01X, manufactured by JGC Catalysts and Chemicals Co., Ltd.), and 199.4 g of 2-octanol (manufactured by Kokura Synthetic Industries Co., Ltd.). The atmosphere in the reactor was replaced with nitrogen and H2 gas three times each, after which the system was pressurized with H2 gas and the catalyst was reduced at 140 °C and 2 MPa for 1 hour. A trap was installed in the exhaust gas line, and the pressure was reduced to 0 MPa while maintaining the temperature at 140 °C. A small amount of nitrogen gas was then introduced through the nitrogen bubbling nozzle to remove the reduced water from the reaction solution. The trapped mass was 5.05 g, of which 1.41 g contained water. The water concentration in the reaction solution was 2743 ppm.

[0047] (Obtaining dimethanol by hydrogenation reaction) Subsequently, the atmosphere in the reactor was replaced with H2 gas three times, and then the system was pressurized with H2 gas to carry out the hydrogenation reaction at 215°C and 9.5 MPa. During the reaction, sampling was carried out every 5 hours. The sample solution was diluted with acetone, and the catalyst was filtered through a membrane filter with a pore size of 0.2 μm. Then, gas chromatography analysis and GC-MS analysis were performed to quantitatively analyze the target compound represented by formula (1a) with a molecular weight of 222 and the ester compound (intermediate) represented by formula (3a) with a molecular weight of 250 as the main product. The quantitative analysis was performed using analytical column 2 (InertCapWAX). After 15 hours, the intermediate represented by formula (3a) was 0.36% (= intermediate represented by formula (3a) / (all components other than 2-octanol and acetone) × 100). After completion of the reaction, the reaction solution was analyzed by gas chromatography using analytical column 1 (InertCap1), and it was confirmed that the reaction solution contained 79.1 g of the target compound represented by formula (1a) (substrate conversion rate 100% (= (charged raw material compound - remaining raw material compound) / charged raw material compound) × 100%)), and the yield of the target compound was 96.5% (= target compound / charged raw material compound × 100%)). The reaction mixture was further purified by simple distillation using a 300 mL three-necked eggplant flask equipped with a thermometer, a N2 bubbling nozzle, and a stirrer (the distillation plate count was one, the distillation temperature was 170-180 °C, and the vacuum was 2 torr). After purification, gas chromatography analysis was performed using analytical column 1 (InertCap1). It was confirmed that the main fraction containing the target compound represented by formula (1a) was 72.8 g, the dimethanol purity was 99.2% (= target compound represented by formula (1a) / (all components other than acetone) × 100), and the distillation yield was 92.0% (= target compound obtained / target compound charged × 100%). Furthermore, analysis was performed using analytical column 2 (InertCapWAX). The intermediate represented by formula (3a) was 0.35% (= intermediate represented by formula (3a) / (all components other than 2-octanol and acetone) × 100). Next, 23.53 g of the obtained main fraction (0.106 mol of the target compound), 23.02 g (0.107 mol) of diphenyl carbonate, and 0.07 mg (0.8 μmol) of sodium bicarbonate were placed in a 300 mL reactor equipped with a stirrer and a distillation device, and transesterification reaction was carried out under a nitrogen atmosphere to obtain a polycarbonate resin. The weight-average molecular weight (Mw) of the obtained polycarbonate resin was 8,000, and the glass transition temperature (Tg) was 110°C.

[0048] <Comparative Example 1> The reaction was carried out in the same manner as in Example 1, except that the operation of dehydrating the reduced water was not performed. After 25 hours, the intermediate represented by formula (3a) was found to be 1.00%. The water concentration in the reaction solution was 7065 ppm. After completion of the reaction, the reaction solution was analyzed by gas chromatography using analytical column 1 (InertCap1), and it was confirmed that the reaction solution contained 77.5 g of the target compound represented by formula (1a) (substrate conversion rate: 100% (= (charged raw material compound - remaining raw material compound) / charged raw material compound) × 100%), and dimethanol yield: 94.5% (= target compound / charged raw material compound × 100%)). The reaction mixture was further purified by simple distillation using a 300 mL three-necked eggplant flask equipped with a thermometer, a N2 bubbling nozzle, and a stirrer (the distillation plate count was one, the distillation temperature was 170-180 °C, and the vacuum was 2 torr). After purification, gas chromatography analysis was performed using analytical column 1 (InertCap1). It was confirmed that the main fraction containing the target compound represented by formula (1a) was 69.0 g, the dimethanol purity was 98.9% (= target compound represented by formula (1a) / (all components other than acetone) × 100), and the distillation yield was 89.0% (= target compound obtained / target compound charged × 100%). Furthermore, analysis was performed using analytical column 2 (InertCapWAX). The intermediate represented by formula (3a) was 0.98% (= intermediate represented by formula (3a) / (all components other than 2-octanol and acetone) × 100). Because no dehydration operation was performed, the effect of reducing the intermediate represented by formula (3a) was low, and the intermediate was mixed in at more than 0.5% in the product. Next, a transesterification reaction was carried out in the same manner as in Example 1, except that the same amount of the main fraction obtained as above was used instead of the main fraction obtained in Example 1, to obtain a polycarbonate resin. The weight average molecular weight (Mw) of the obtained polycarbonate resin was 6,800, and the glass transition temperature (Tg) was 105°C.

[0049] <Example 2> The reaction was carried out in the same manner as in Example 1, except that the hydrogenation catalyst was changed to 9.16 g. The trapped amount was 3.01 g, of which the water content was 0.85 g. The water concentration in the reaction solution was 2585 ppm. After 25 hours of hydrogenation, the intermediate represented by formula (3a) was 0.44%. After completion of the reaction, the reaction solution was analyzed by gas chromatography using analytical column 1 (InertCap1), and it was confirmed that the reaction solution contained 78.7 g of the target compound represented by formula (1a) (substrate conversion rate 100% (= (charged raw material compound - remaining raw material compound) / charged raw material compound) × 100%), and dimethanol yield 96.0% (= main product / charged aldehyde × 100%)). The reaction mixture was further purified by simple distillation using a 300 mL three-necked eggplant flask equipped with a thermometer, a N2 bubbling nozzle, and a stirrer (the distillation plate count was one, the distillation temperature was 170-180 °C, and the vacuum was 2 torr). After purification, gas chromatography analysis was performed using analytical column 1 (InertCap1). It was confirmed that the main fraction containing the target compound represented by formula (1a) was 71.6 g, the dimethanol purity was 99.1% (= target compound represented by formula (1a) / (all components other than acetone) × 100)), and the distillation yield was 91.0% (= target compound obtained / target compound charged × 100%). Furthermore, analysis was performed using analytical column 2 (InertCapWAX). The intermediate represented by formula (3a) was 0.43% (= intermediate represented by formula (3a) / (all components other than 2-octanol and acetone) × 100). Because a dehydration operation was performed, even if the catalyst was reduced, the effect of reducing the intermediate represented by formula (3a) was high, and the intermediate content in the product was less than 0.5%. Next, a transesterification reaction was carried out in the same manner as in Example 1, except that the same amount of the main fraction obtained as above was used instead of the main fraction obtained in Example 1, to obtain a polycarbonate resin. The weight average molecular weight (Mw) of the obtained polycarbonate resin was 7,850, and the glass transition temperature (Tg) was 109°C.

[0050] Example 3 The reaction was carried out in the same manner as in Example 2, except that a nitrogen bubbling nozzle was not installed and the gas phase was purged four times from 0.5 MPa to 0 MPa. The trapped amount was 1.08 g, of which the water content was 0.34 g. The water concentration in the reaction solution was 4354 ppm. After 25 hours of hydrogenation, the ester compound represented by formula (3a) was 0.48%. After completion of the reaction, the reaction solution was analyzed by gas chromatography using analytical column 1 (InertCap1), and it was confirmed that the reaction solution contained 78.7 g of the target compound represented by formula (1a) (substrate conversion rate: 100% (= (charged raw material compound - remaining raw material compound) / charged raw material compound) × 100%), and dimethanol yield: 95.0% (= target compound / charged raw material compound × 100%)). The reaction mixture was further purified by simple distillation using a 300 mL three-necked eggplant flask equipped with a thermometer, a N2 bubbling nozzle, and a stirrer (the distillation plate count was one, the distillation temperature was 170-180 °C, and the vacuum was 2 torr). After purification, gas chromatography analysis was performed using analytical column 1 (InertCap1). It was confirmed that the main fraction containing the target compound represented by formula (1a) was 71.5 g, the dimethanol purity was 99.0% (= target compound represented by formula (1a) / (all components other than acetone) × 100)), and the distillation yield was 90.0% (= target compound obtained / target compound charged × 100%). Furthermore, analysis was performed using analytical column 2 (InertCapWAX). The intermediate represented by formula (3a) was 0.46% (= intermediate represented by formula (3a) / (all components other than 2-octanol and acetone) × 100). The water concentration in the reaction solution was reduced to 4500 ppm or less by dehydration, which was highly effective in reducing the intermediate represented by formula (3a), and the intermediate content in the product was less than 0.5%. Next, a transesterification reaction was carried out in the same manner as in Example 1, except that the same amount of the main fraction obtained as above was used instead of the main fraction obtained in Example 1, to obtain a polycarbonate resin. The weight average molecular weight (Mw) of the obtained polycarbonate resin was 7,800, and the glass transition temperature (Tg) was 109°C.

[0051] The reaction conditions and results of the reaction in Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

[0052] [Table 1]

[0053] This application is based on a Japanese patent application (Patent Application No. 2021-067254) filed on April 12, 2021, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0054] According to the production method of the present invention, a dimethanol compound having a norbornane skeleton, which is useful as a paint additive, adhesive, resin raw material, etc., can be produced in an industrially advantageous manner.

Claims

1. A method for producing a target compound represented by the following formula (1): The method includes a step (A) of subjecting a mixed liquid containing a raw material compound represented by the following formula (2) and a solvent to hydrogenation reduction in the presence of a catalyst having hydrogenation ability, In the step (A), water is removed from the reaction system. 【Chemistry 1】 (In the formula (1), R is H, CH 3 , or C 2 H 5 Represents.) 【Chemistry 2】 (In the formula (2), R is H, CH 3 , or C 2 H 5 Represents R 1 is CH 3 , C 2 H 5 , C 3 H 7 , or C 4 H 9 Represents.)

2. 2. The method according to claim 1, wherein the water content of the mixture measured after the removal of water is 4500 ppm or less.

3. 3. The production method according to claim 1 or 2, wherein in the step (A), the catalyst is activated at a first temperature and a first pressure, and after the activation, the raw material compound is hydrogenated at a second temperature and a second pressure.

4. The process according to claim 3, wherein the removal of water is carried out before the hydrogenation.

5. the first temperature and the first pressure are 100°C or higher and 170°C or lower and 0.5 MPa or higher and 5 MPa or lower, respectively; The method according to claim 3 or 4, wherein the second temperature and the second pressure are higher than 170°C and lower than 250°C and higher than 5 MPa and lower than 20 MPa, respectively.

6. The method according to any one of claims 1 to 5, wherein the content of the intermediate represented by the following formula (3) in the target compound is 0.5 mass% or less: 【Transformation 3】 (In the formula (3), R and R1 have the same meanings as in the formula (2).)

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