Method for producing tricyclodecane dimethanol

Abstract

To provide a method of manufacturing efficiently and with high yield high purity tricyclodecane dimethanol, by hydrogenating tricyclodecanedicarbalaldehyde obtained by hydroformylation of dicyclopentadiene.SOLUTION: A manufacturing method of tricyclodecanedimethanol in which in a method of manufacturing tricyclodecanedimethanol by hydrogenating tricyclodecane dicarbaldehydes obtained by hydroformylation of dicyclopentadiene, the hydrogenation is performed under the presence of a specific amount of water and a ruthenium catalyst.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing tricyclodecane dimethanol by hydrogenating tricyclodecane dicarbaldehydes obtained by hydroformylation of dicyclopentadiene. [Background technology]

[0002] A well-known method is to hydroformylate dicyclopentadiene to obtain tricyclodecane dicarbaldehyde, which is then hydrogenated to produce tricyclodecane dimethanol.

[0003] In the purification step after the hydroformylation reaction of dicyclopentadiene, purification by extraction is often carried out. For example, Patent Document 1 describes a method in which an extraction solvent consisting of a polyhydric alcohol having 2 to 6 carbon atoms is added to the hydroformylation reaction solution to perform extraction. Furthermore, Patent Document 2 describes a method in which a primary alkanol and water are added to the hydroformylation reaction solution to perform extraction.

[0004] As described above, alcohols are primarily used as extraction solvents, and it is known that alcohols form acetals with tricyclodecane dicarbaldehyde. However, because the reduction reaction rate of acetals by hydrogenation is extremely slow, the presence of acetals in tricyclodecane dicarbaldehyde significantly reduces the productivity of the process for producing tricyclodecane dimethanol by hydrogenation. Furthermore, if the acetal remains as an acetal without being hydrogenated, the acetal has a similar boiling point to tricyclodecane dimethanol, making distillation separation difficult. Therefore, the acetal remains in the final product, tricyclodecane dimethanol, causing a decrease in its purity.

[0005] Patent Document 1 describes the addition of an amine to suppress the formation of acetal, but there is a risk that the added amine will contaminate the tricyclodecane dimethanol.

[0006] Patent Document 3 describes that when tricyclodecane dicarbaldehyde is hydrogenated in the presence of water and a Ni catalyst, the yield of tricyclodecane dimethanol can be increased compared to when water is not present. However, when acetal is contained in the raw material before hydrogenation, the reaction rate becomes very slow, and therefore a high yield cannot be obtained within a specified reaction time. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-10999 [Patent Document 2] Special Publication No. 6-501958 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-350462 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for efficiently producing high-purity tricyclodecane dimethanol in a high yield by hydrogenating tricyclodecane dicarbaldehydes obtained by hydroformylation of dicyclopentadiene. [Means for solving the problem]

[0009] As a result of extensive investigations conducted by the present inventors to solve the above-mentioned problems, they found that by hydrogenating tricyclodecane dicarbaldehydes in the presence of water and a ruthenium catalyst, the acetal compound can be rapidly converted to tricyclodecane dicarbaldehyde during the hydrogenation reaction of tricyclodecane dicarbaldehyde, and tricyclodecane dicarbaldehyde converted from the acetal compound can be hydrogenated, thereby producing tricyclodecane dimethanol in high yield. That is, the present invention is summarized as follows.

[0010] [1] A method for producing tricyclodecane dimethanol by hydrogenating tricyclodecane dicarbaldehydes obtained by hydroformylation of dicyclopentadiene, wherein the hydrogenation is carried out in a reaction solution having a water content of 2% by weight or more in the presence of a ruthenium catalyst.

[0011] [2] The method for producing tricyclodecanedimethanol according to [1], wherein the tricyclodecanedicarbaldehydes contain an acetal compound.

[0012] [3] The method for producing tricyclodecanedimethanol according to [1] or [2], wherein the ratio of the acetal compound to the tricyclodecanedicarbaldehyde in the tricyclodecanedicarbaldehydes is 0.1 to 50% by weight.

[0013] [4] The method for producing tricyclodecanedimethanol according to [3], wherein the ratio of the acetal compound to the tricyclodecanedicarbaldehyde in the tricyclodecanedicarbaldehydes is 1 to 25% by weight.

[0014] [5] The method for producing tricyclodecane dimethanol according to any one of [1] to [4], wherein the hydrogenation reaction liquid has a water content of 10 to 20% by weight. [Effects of the Invention]

[0015] According to the present invention, in a method for producing tricyclodecane dimethanol by hydrogenating tricyclodecane dicarbaldehydes obtained by hydroformylation of dicyclopentadiene, the hydrogenation is carried out in the presence of water and a ruthenium catalyst, whereby an acetal compound contained in the tricyclodecane dicarbaldehydes is rapidly converted to tricyclodecane dicarbaldehyde during the hydrogenation reaction, and tricyclodecane dicarbaldehyde converted from the acetal compound is hydrogenated, thereby producing tricyclodecane dimethanol in a high yield. In the present invention, the tricyclodecane dicarbaldehydes and acetal compounds in the target tricyclodecane dimethanol can be reduced without adding compounds such as amines that may become contaminants of tricyclodecane dimethanol, and therefore high-purity tricyclodecane dimethanol with few impurities can be efficiently obtained. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below.

[0017] The method for producing tricyclodecane dimethanol of the present invention is characterized in that it is produced by hydrogenating tricyclodecane dicarbaldehydes obtained by hydroformylation of dicyclopentadiene, and the hydrogenation is carried out in the presence of water and a ruthenium catalyst. Here, the tricyclodecane dicarbaldehydes refer to a mixture of tricyclodecane dicarbaldehyde and acetal compounds obtained by acetalization of tricyclodecane dicarbaldehyde.

[0018] <Hydroformylation of dicyclopentadiene> In the present invention, the method for hydroformylating dicyclopentadiene is not particularly limited, and can be carried out according to a conventional method. For example, according to the method described in Patent Document 1, tricyclodecane dicarbaldehyde can be produced by hydroformylating dicyclopentadiene using hydrogen and carbon monoxide in a hydroformylation reaction solvent comprising a hydrocarbon compound in the presence of a catalyst comprising a rhodium compound and an organophosphorus compound, as shown in reaction formula (I) below.

[0019] [ka]

[0020] The rhodium compound used in this hydroformylation step can be any precursor, as long as it forms a complex with an organophosphorus compound and exhibits hydroformylation activity in the presence of hydrogen and carbon monoxide. 12 ,Rh6(CO) 16 A catalyst precursor such as Rh(NO3)3 may be introduced into the reaction mixture together with an 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 catalyst may be prepared in advance and then introduced into the reaction vessel. In a preferred embodiment of the present invention, Rh(acac)(CO)2 is used as the rhodium precursor material, reacted with an organophosphorus compound in the presence of a solvent, and then introduced into the reactor together with an excess of free organophosphorus compound to form a catalytically active rhodium-organophosphorus complex catalyst. In any event, for purposes of the present invention, it is sufficient that an active rhodium-organophosphorus catalyst be present in the reaction mixture under the conditions of carbon monoxide and hydrogen used in the hydroformylation reaction.

[0021] The organic phosphorus compounds that form catalysts for the hydroformylation reaction with rhodium compounds include phosphites and phosphines. Among these, phosphites are effective in the hydroformylation reaction of dicyclopentadiene, and are therefore represented by the general formula P(-OR 1 )(-OR 2 )(-OR 3 )(wherein, R 1 ,R 2 and R 3 R represents an optionally substituted aryl group or alkyl group. 1 ,R 2 and R 3Specific examples of the alkyl group include aryl groups such as phenyl and naphthyl which may be substituted with a methyl group, ethyl group, isopropyl group, n-butyl group, t-butyl group, methoxy group, etc.; aliphatic alkyl groups such as methyl group, ethyl group, isopropyl group, n-butyl group, t-butyl group, etc.; and alicyclic alkyl groups such as cyclopentyl and cyclohexyl which may be substituted with a lower alkyl group such as a methyl group, ethyl group, isopropyl group, n-butyl group, t-butyl group, etc.

[0022] Specific examples of suitable phosphites include, but are not limited to, tris(2-t-butylphenyl)phosphite, tris(3-methyl-6-t-butylphenyl)phosphite, tris(3-methoxy-6-t-butylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, di(2-t-butylphenyl)(t-butyl)phosphite, etc. These phosphites may be used alone or in combination of two or more.

[0023] On the other hand, as phosphines, sterically hindered alkylphosphines are particularly effective in the hydroformylation reaction of dicyclopentadiene. Representative examples include, but are not limited to, tricyclopropylphosphine, tricyclobutylphosphine, tricyclopentylphosphine, tricyclohexylphosphine, tricycloheptylphosphine, and tricyclooctylphosphine. These phosphines may be used alone or in combination of two or more.

[0024] The amount of the organophosphorus compound used is in the range of 1 to 400 times by mole, preferably 3 to 200 times by mole, relative to the rhodium metal in the hydroformylation reaction solution, so that tricyclodecane dicarbaldehyde can be obtained at a sufficient hydroformylation reaction rate. The hydroformylation reaction of dicyclopentadiene can be carried out without using a solvent, but is more preferably carried out using an organic solvent inert to the reaction.

[0025] As will be described later, after completion of the hydroformylation reaction, the reaction product liquid containing tricyclodecane dicarbaldehyde is contacted with an alcohol to extract tricyclodecane dicarbaldehyde into an extraction solvent layer comprising alcohol, while leaving the catalyst components in the dihydroformylation reaction solvent layer, and then layer separation is carried out. Therefore, the hydroformylation reaction solvent is preferably one that undergoes layer separation from the alcohol. Examples of such solvents include aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, and alicyclic hydrocarbon compounds.

[0026] Suitable aromatic hydrocarbon compounds include benzene, methylbenzenes such as toluene, xylene, mesitylene, and pseudocumene, ethylbenzenes such as ethylbenzene, diethylbenzene, and triethylbenzene, propylbenzenes such as isopropylbenzene, 1,3-diisopropylbenzene, and 1,4-diisopropylbenzene, and various other alkylbenzenes. Examples of aliphatic hydrocarbon compounds include pentane, hexane, heptane, octane, isooctane, dodecane, and decane, but are not limited to these, as long as they are liquid at standard temperature and pressure. As the alicyclic hydrocarbon compound, cyclohexane, cyclooctane, cyclododecane, decalin, methylcyclohexane, etc. are preferably used.

[0027] The amount of rhodium catalyst used is usually 50 to 5000 ppm, more preferably 50 to 2000 ppm, of rhodium metal relative to the starting dicyclopentadiene. When rhodium is used at 50 ppm or more, it becomes necessary to recover the catalyst.

[0028] The temperature and pressure for the hydroformylation reaction of dicyclopentadiene are usually 40 to 160°C, preferably 80 to 140°C, and usually 1 to 15 MPa. If the temperature is lower than 40°C, the hydroformylation reaction slows down, while if it is higher than 160°C, side reactions from dicyclopentadiene and the hydroformylation reaction product in the reaction liquid proceed, resulting in a lower aldehyde yield. Furthermore, if the pressure is lower than 1 MPa, the hydroformylation reaction slows down, and if it is higher than 15 MPa, a high-pressure reactor must be used, resulting in higher equipment costs.

[0029] The molar ratio of hydrogen to carbon monoxide in the hydrogen / carbon monoxide mixed gas used in the reaction can be selected from the range of 0.2 to 5.0 as the introduced gas composition (hydrogen / carbon monoxide). If the hydrogen / carbon monoxide mixed gas is outside this range, the reaction activity or aldehyde selectivity of the hydroformylation reaction will decrease.

[0030] The hydroformylation reaction is carried out using a continuous feed method in which the raw material dicyclopentadiene is fed alone or as a mixed solution of dicyclopentadiene and a solvent to a reactor containing a rhodium-organophosphorus complex catalyst, a solvent, and a mixed gas of hydrogen and carbon monoxide. This method reduces the production of cyclopentadiene, which inhibits the hydroformylation reaction due to thermal decomposition of dicyclopentadiene in the reactor, and maintains a good reaction rate and yield. To maintain the fluidity of dicyclopentadiene, it is preferable to dilute it with the aforementioned solvent and feed it to the reactor at a temperature at which it does not depolymerize and produce cyclopentadiene.

[0031] <Extraction of tricyclodecane dicarbaldehyde> After completion of the hydroformylation reaction, the reaction product liquid is contacted with an alcohol either as is or after being diluted with the hydrocarbon compound used as the hydroformylation reaction solvent in the reaction or with another hydrocarbon compound, and the product tricyclodecane dicarbaldehyde is extracted into the alcohol while the catalyst components remain in the hydroformylation reaction solvent layer, followed by layer separation.

[0032] Examples of alcohols include primary alcohols having 1 to 3 carbon atoms and polyhydric alcohols having 2 to 6 carbon atoms. Examples of primary alcohols include methanol, ethanol, and propanol. Examples of polyhydric alcohols having 2 to 6 carbon atoms include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, and isomers of pentanediol, neopentyl glycol, hexanediol, glycerin, pentaerythritol, and trimethylolpropane. Among these, methanol, ethylene glycol, propanediols, and butanediols are preferred because they have relatively low boiling points, are inexpensive, and are easy to handle as liquids. These extraction solvents may be used alone or in combination of two or more. Alternatively, extraction may be carried out in the presence of water in addition to the alcohol, as the addition of water facilitates the distribution of the aldehyde and catalyst components into each layer.

[0033] It is preferable that the reaction solvent and extraction solvent used in the hydroformylation reaction have different densities in order to achieve effective layer separation. One suitable example of a combination of a hydroformylation reaction solvent containing tricyclodecane dicarbaldehyde and an extraction solvent is a combination of methylcyclohexane and ethylene glycol, or a combination of methylcyclohexane, methanol, and water.

[0034] The distribution of tricyclodecanedicarbaldehyde between the hydroformylation reaction solvent and the extraction solvent is equilibrium. In contrast, the catalyst components, rhodium and organophosphorus compounds, are present essentially exclusively in the hydroformylation reaction solvent, with concentrations in the extraction solvent below analytical limits. The volume ratio of the extraction solvent to the reaction product solution used is determined by the solubility of tricyclodecanedicarbaldehyde in the extraction solvent and the amount of tricyclodecanedicarbaldehydes to be extracted. For example, if the tricyclodecanedicarbaldehyde to be separated is highly soluble in the extraction solvent and present at low concentrations in the reaction product solution, practical extraction of tricyclodecanedicarbaldehydes is possible using a low volume ratio (extraction solvent / reaction product solution). The higher the product concentration, the higher the volume ratio (extraction solvent / reaction product solution) required to extract tricyclodecanedicarbaldehydes from the reaction product solution. When tricyclodecane dicarbaldehydes have relatively low solubility in the extraction solution, the volume ratio can vary within the range of 10:1 to 1:10. Furthermore, in order to increase the amount of tricyclodecane dicarbaldehyde extracted using a small amount of extraction solvent, it is effective to use separate extraction solvents and perform the extraction procedure several times. Furthermore, in the final extraction step, a hydroformylation reaction solvent such as methylcyclohexane may be added in an amount of approximately 5 to 20% by weight relative to the reaction product solution. Addition of the hydroformylation reaction solvent can improve the catalyst removal rate.

[0035] The temperature at which the extraction operation is carried out is not particularly limited, but it is practical to carry out the operation at or below the hydroformylation reaction temperature. After the reaction in the hydroformylation reactor, an extraction solvent may be added to carry out the extraction operation, or the hydroformylation reaction product liquid may be withdrawn from the hydroformylation reactor and the operation may be carried out in an extraction tank. It is also possible to carry out the extraction operation by directly adding an extraction solvent to the hydroformylation reactor, and retain the catalyst components in the hydroformylation reactor as they are to carry out the next hydroformylation reaction. When the hydroformylation reaction product liquid is withdrawn and the operation is carried out in an extraction tank, the hydrocarbon solvent layer containing the catalyst is returned to the hydroformylation reactor and used again in the reaction. This process can be carried out as either a batch process or a continuous process.

[0036] The above-described extraction procedure can yield a tricyclodecane dicarbaldehyde-containing solution containing 10 to 90% by weight of tricyclodecane dicarbaldehydes, 10 to 90% by weight of extraction solvent, or 5 to 90% by weight of tricyclodecane dicarbaldehydes, 5 to 90% by weight of extraction solvent, and 5 to 90% by weight of reaction solvent when a reaction solvent is added. Note that the alcohol in the extraction solvent reacts with a portion of the hydroformylation product tricyclodecane dicarbaldehyde to produce an acetal compound in which tricyclodecane dicarbaldehyde is acetalized. The content of the acetal compound in the tricyclodecane dicarbaldehyde is usually about 0.1 to 50% by weight, and preferably about 1 to 25% by weight.

[0037] <Hydrogenation reaction> The extract containing tricyclodecane dicarbaldehydes (tricyclodecane dicarbaldehyde-containing solution) obtained by the above extraction operation is then hydrogenated in the presence of water and a ruthenium (Ru) catalyst to produce tricyclodecane dimethanol as shown in the following reaction formula (II).

[0038] [ka]

[0039] The Ru catalyst may be Ru metal alone or a Ru compound such as Ru oxide, and these may be used in the form of a Ru complex or the like, supported on an inorganic support such as silica, alumina, diatomaceous earth, or carbon.

[0040] The amount of water present in the hydrogenation reaction is preferably equal to or greater than the amount of acetal compound in the hydrogenation reaction solution, but is an amount sufficient to prevent phase separation of the reaction solution. The water content of the entire reaction solution is preferably 2% by weight or more, preferably 2 to 30% by weight, more preferably 5 to 25% by weight, and particularly preferably 10 to 20% by weight. When the water content is within the above range, phase separation between the water and the reaction solvent does not occur, and the aforementioned effects of having water present in the hydrogenation reaction system can be effectively achieved in the present invention. In the present invention, water may be added in an extraction step in which the catalyst component and dialdehydes are separated from the hydroformylation reaction product solution, or may be added to the reaction system immediately before the hydrogenation reaction.

[0041] The reaction may be carried out in a batchwise manner by adding the catalyst as a slurry to a stirred reactor and separating the catalyst from the product liquid by settling and filtering after the reaction, or by a trickle reaction by adding a formed catalyst to a tubular reactor and flowing the product liquid and hydrogen gas over the catalyst. There are no particular restrictions on the amount of catalyst used as long as tricyclodecane dimethanol can be produced with industrially advantageous productivity.

[0042] The reaction temperature and pressure of the hydrogenation reaction are usually 40 to 200°C, preferably 70 to 150°C, and the reaction pressure is usually 10 MPa or less. If the temperature is lower than 40°C, the hydrogenation reaction is slow, and if it is higher than 200°C, side reactions from the target product, tricyclodecane dimethanol, proceed, resulting in a lower yield of tricyclodecane dimethanol. Furthermore, if the pressure is higher than 10 MPa, a high-pressure reaction apparatus will be required, which increases the equipment costs.

[0043] The crude reaction mixture containing tricyclodecane dimethanol thus obtained can be recovered and purified by simple handling. For example, the solvent is distilled off to obtain a crude product, and tricyclodecane dimethanol can be separated and purified by thin-film evaporation, distillation, or other procedures to obtain a final product. [Example]

[0044] The present invention will be described in more detail below with reference to examples.

[0045] [Example 1] <Hydroformylation reaction> A stainless steel autoclave was charged with 250.1 mg (0.194 mmol) of Rh(acac)(CO), 3.78 g (5.83 mmol) of tris(2,4-di-t-butylphenyl)phosphite, 91.7 g of dicyclopentadiene, and 62.4 g of methylcyclohexane under a nitrogen atmosphere. After sealing the autoclave, it was heated to 70 °C in an electric furnace. A hydrogen / carbon monoxide mixed gas (mixture ratio: 1 / 1) was rapidly introduced through the gas inlet valve until the pressure inside the autoclave reached 5 MPa. The mixture was stirred with an up-and-down stirrer and reacted for 0.5 hours. The mixture was then heated to 100 °C in an electric furnace and reacted for an additional 1.5 hours. During the reaction, the mixed gas consumed during the reaction was automatically introduced into the autoclave via an automatic pressure control valve to maintain the pressure inside the autoclave at 5 MPa. After the reaction was completed, the mixture was cooled to room temperature and the remaining gas was released to give 191.1 g of a hydroformylation reaction product liquid. Analysis of the reaction product liquid by gas chromatography revealed that the yield of tricyclodecane dicarbaldehyde was 98%.

[0046] <Extraction operation> To 77.8 g of the hydroformylation reaction product liquid obtained above, 46.3 g of ethylene glycol was added and stirred under a nitrogen atmosphere. After that, the mixture was left to stand for 10 minutes, and the mixture was separated into two phases, followed by an extraction operation. 7.0 g of methylcyclohexane was added to the obtained lower phase (a1), and the mixture was stirred. After that, the mixture was left to stand for 10 minutes, and the mixture was separated into two phases, followed by an extraction operation, yielding 103 g of lower phase (a2). Analysis by gas chromatography revealed that the composition of the resulting lower phase (a2) was 48% by weight of tricyclodecane dicarbaldehydes, 45% by weight of ethylene glycol, and 7% by weight of methylcyclohexane. Furthermore, analysis by gas chromatography revealed that the content of acetal compounds in the tricyclodecane dicarbaldehydes was 23% by weight based on the tricyclodecane dicarbaldehyde.

[0047] <Hydrogenation reaction> A stainless steel autoclave was charged with 22.7 g of the lower layer (a2) obtained by the extraction operation, 5.2 g of water, and 0.55 g of Ru / C (Ru content 5 wt%, water content 57.6 wt%) (the water content in the reaction solution was 18 wt%). After sealing the autoclave and heating it to 100°C in an electric furnace, hydrogen gas was quickly introduced through the gas inlet valve until the pressure inside the autoclave reached 5 MPa. The reaction was carried out for 1 hour while stirring with an induction stirrer. During the reaction, hydrogen gas consumed in the reaction was automatically introduced into the autoclave via an automatic pressure control valve, and the reaction was carried out while constantly maintaining the pressure inside the autoclave at 5 MPa. After the reaction was completed, the mixture was cooled to room temperature, and the remaining gas was released to obtain 24.2 g of a reaction product liquid. Analysis of the reaction product liquid by gas chromatography revealed that the yield of tricyclodecane dimethanol was 96%. The ratio of the acetal compound to tricyclodecane dimethanol was 1% by weight.

[0048] [Example 2] <Extraction operation> To 116.0 g of the hydroformylation reaction product liquid obtained in Example 1, 31.5 g of methanol and 18.0 g of water were added and stirred under a nitrogen atmosphere. The mixture was then allowed to stand for 10 minutes, allowing it to separate into two phases and undergoing extraction. 2.2 g of methylcyclohexane was added to the resulting lower phase (b1), and the mixture was stirred. The mixture was then allowed to stand for 10 minutes, allowing it to separate into two phases and undergoing extraction, yielding 136 g of lower phase (b2). Analysis was performed in the same manner as in Example 1, revealing that the composition of the resulting lower phase (b2) was 56 wt% tricyclodecane dicarbaldehydes, 23 wt% methanol, 13 wt% water, and 7 wt% methylcyclohexane. The content of acetal compounds in the tricyclodecane dicarbaldehydes was 8 wt% relative to the tricyclodecane dicarbaldehyde.

[0049] <Hydrogenation reaction> A stainless steel autoclave was charged with 97.5 g of the lower layer (b2) obtained by the extraction operation and 1.15 g of Ru / C (Ru content: 5 wt %, water content: 57.6 wt %) (13 wt % in the reaction solution). After sealing the autoclave and heating it to 120 °C in an electric furnace, hydrogen gas was rapidly introduced through the gas inlet valve until the pressure inside the autoclave reached 5 MPa. The reaction was carried out for 2 hours while stirring with an induction stirrer. During the reaction, hydrogen gas consumed in the reaction was automatically introduced into the autoclave via an automatic pressure control valve, and the pressure inside the autoclave was constantly maintained at 5 MPa. After hydrogen gas consumption stopped and the reaction was confirmed to be complete, the autoclave was cooled to room temperature, the remaining gas was released, and the reaction product solution was analyzed by gas chromatography. The yield of tricyclodecane dimethanol was 96%. Furthermore, no acetal compounds remained.

[0050] [Comparative Example 1] The hydrogenation reaction in Example 1 was carried out in the same manner as described below, except that Raney nickel was used instead of Ru / C. 2.5 g of Raney nickel was added little by little to 15.9 g of a 25 wt % aqueous solution of sodium hydroxide while cooling at 0° C. After the entire amount was added, the mixture was heated at 50° C. for 50 minutes. After cooling to room temperature, the resulting solid was washed with water until the washing liquid became neutral. The resulting Raney nickel, 25.3 g of the lower layer obtained by the extraction operation, and 5.2 g of water were charged into a stainless steel autoclave. After sealing the autoclave and heating it to 100°C in an electric furnace, hydrogen gas was quickly introduced through the gas inlet valve until the pressure inside the autoclave reached 5 MPa, and the reaction was carried out for 1 hour while stirring with an induction stirrer. During the reaction, hydrogen gas consumed in the reaction was automatically introduced into the autoclave via an automatic pressure regulating valve, and the reaction was carried out while constantly maintaining the pressure inside the autoclave at 5 MPa. After the reaction was completed, the mixture was cooled to room temperature, and the remaining gas was released to obtain 24.6 g of reaction product liquid. Analysis of the reaction product liquid by gas chromatography revealed that the yield of tricyclodecane dimethanol was 84%. The ratio of acetal compounds to tricyclodecane dimethanol was 17% by weight.

[0051] Comparative Example 2 In Example 1, the reaction was carried out as follows under the condition that the water content of the reaction solution was below the range specified in the present application. A stainless steel autoclave was charged with 25.2 g of the lower layer obtained by the extraction operation and 0.55 g of Ru / C (Ru content 5 wt%, water content 57.6 wt%) (water content of the reaction solution was 1.2 wt%). After sealing the autoclave and heating it to 100°C in an electric furnace, hydrogen gas was quickly introduced through the gas inlet valve until the pressure inside the autoclave reached 5 MPa, and the reaction was carried out for 1 hour while stirring with an induction stirrer. During the reaction, hydrogen gas consumed in the reaction was automatically introduced into the autoclave via an automatic pressure regulating valve, and the reaction was carried out while constantly maintaining the pressure inside the autoclave at 5 MPa. After the reaction was completed, the mixture was cooled to room temperature, and the remaining gas was released to obtain 24.2 g of a reaction product liquid. Analysis of the reaction product liquid by gas chromatography revealed that the yield of tricyclodecane dimethanol was 69%. The ratio of the acetal compound to tricyclodecane dimethanol was 40% by weight.

[0052] From the results of Examples 1 and 2 and Comparative Examples 1 and 2 described above, it can be seen that according to the present invention, by carrying out the hydrogenation reaction of tricyclodecane dicarbaldehydes in the presence of a Ru catalyst and water, the acetal compound can be rapidly converted into tricyclodecane dicarbaldehyde during the hydrogenation reaction, and tricyclodecane dicarbaldehyde converted from the acetal compound can be hydrogenated, thereby producing tricyclodecane dimethanol in high yield. In contrast, such effects were not obtained in Comparative Example 1, in which a Ni catalyst was used instead of a Ru catalyst, or in Comparative Example 2, in which the water content of the reaction liquid was below the range specified in the present application.

Claims

1. A method for producing tricyclodecane dimethanol by hydrogenating tricyclodecane dicarbaldehydes obtained by hydroformylation of dicyclopentadiene, wherein the hydrogenation is carried out in a reaction solution having a water content of 10 to 30% by weight in the presence of a ruthenium catalyst.

2. 2. The method for producing tricyclodecanedimethanol according to claim 1, wherein the tricyclodecanedicarbaldehydes contain an acetal compound.

3. 3. The method for producing tricyclodecanedimethanol according to claim 1, wherein the ratio of the acetal compound to the tricyclodecanedicarbaldehyde in the tricyclodecanedicarbaldehydes is 0.1 to 50% by weight.

4. 4. The method for producing tricyclodecanedimethanol according to claim 3, wherein the ratio of the acetal compound to the tricyclodecanedicarbaldehyde in the tricyclodecanedicarbaldehydes is 1 to 25% by weight.

5. The method for producing tricyclodecane dimethanol according to any one of claims 1 to 4, wherein the hydrogenation reaction liquid has a water content of 10 to 20% by weight.

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