Methods for producing cyclohexanedicarboxylic acid compounds, cyclohexanedimethanol, polyester resins, and polycarbonate resins.

Abstract

To provide a method for producing a cyclohexanedicarboxylic acid-based compound which can simply obtain a cyclohexanedicarboxylic acid-based compound such as DMCD from a polymer having a terephthalic acid skeleton at a sufficient yield at low cost.SOLUTION: A method for producing a cyclohexanedicarboxylic acid-based compound includes performing exchange reaction of an ester group or an amide group and alcohol or water in the presence of a catalyst A, and nuclear hydrogenation reaction in the presence of the catalyst A and a nuclear hydrogenation catalyst B, on a polymer having a terephthalic acid skeleton containing an ester group or an amide group, and thereby obtaining a cyclohexanedicarboxylic acid or a cyclohexanedicarboxylic acid ester, wherein the catalyst A containing at least one selected from Group 2 elements (excluding strontium) and Group 3 elements, and the nuclear hydrogenation catalyst containing at least one selected from a catalyst containing ruthenium, and a platinum-carrying catalyst in which platinum is carried on silica are used.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to methods for producing cyclohexanedicarboxylic acid compounds, cyclohexanedimethanol, polyester resins, and polycarbonate resins. [Background technology]

[0002] Dimethyl-1,4-cyclohexanecarboxylate (DMCD) and other cyclohexanedicarboxylic acids or cyclohexanedicarboxylic acid esters are useful as raw materials for polyester resins. 1,4-cyclohexanedimethanol (CHDM) is also useful as a raw material for polyester and polycarbonate resins, and has recently attracted particular attention as a raw material for PETG resins.

[0003] While waste plastics are typically recycled using methods such as material recycling, it is generally known that maintaining the polymer structure during purification is difficult, leading to quality degradation (downcycling) during the recycling process. In contrast, chemical recycling of waste plastics allows for the production of high-quality compounds (upcycling) because the purification of the resulting products is easier compared to the raw polymers. If DMCD or CHDM can be obtained from waste plastics, the waste plastics can be recycled through upcycling, reducing the environmental impact. Patent Document 1 discloses a method for obtaining CHDM by depolymerizing a polyester mainly composed of alkylene terephthalate units in the presence of a glycol having 10 or fewer carbon atoms, hydrogen, and a hydrogenation catalyst, followed by catalytic reduction. Patent Document 2 discloses a method for obtaining CHDM by depolymerizing a polyester mainly composed of alkylene terephthalate units in the presence of a lower alcohol, hydrogen, and a hydrogenation catalyst, followed by catalytic reduction. Non-patent document 1 discloses a method for obtaining DMCD or CHDM by alcohol decomposing polyethylene terephthalate in the presence of zinc acetate, a transesterification catalyst, removing the transesterification catalyst which interferes with the nuclear hydrogenation reaction by purification, and then performing nuclear hydrogenation. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 50-142537 [Patent Document 2] Japanese Patent Application Publication No. 50-130738 [Non-patent literature]

[0005] [Non-Patent Document 1] ChemistrySelect (2020), 5(32), 10010-10014 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the methods described in Patent Documents 1 and 2 produce cyclohexanedicarboxylic acids or cyclohexanedicarboxylic acid esters such as DMCD as intermediates, but the yield of DMCD is low, and the resulting mixture is complex and contains polymers, making purification difficult. Furthermore, the method described in Non-Patent Document 1 requires purification to remove the transesterification catalyst after alcohol decomposition, which tends to complicate the manufacturing process and increase costs. Non-Patent Document 1 investigates the coexistence of the transesterification catalyst and the nuclear hydrogenation catalyst in order to simplify the purification process, but it states that the nuclear hydrogenation catalyst is poisoned, preventing nuclear hydrogenation from proceeding at all.

[0007] The present invention aims to provide a method for producing cyclohexanedicarboxylic acid compounds, such as DMCD, from polymers having a terephthalic acid skeleton in a simple, low-cost, and sufficient yield. Furthermore, the invention aims to provide a method for producing cyclohexanedimethanol, polyester resins, and polycarbonate resins using the aforementioned method for producing cyclohexanedicarboxylic acid compounds. [Means for solving the problem]

[0008] The present invention includes the following embodiments. [1] The process includes obtaining cyclohexanedicarboxylic acid or cyclohexanedicarboxylic acid ester by performing an exchange reaction between the ester group or amide group and an alcohol or water in the presence of catalyst A and a nuclear hydrogenation reaction in the presence of catalyst A and nuclear hydrogenation catalyst B on a polymer having a terephthalic acid skeleton containing an ester group or an amide group, The catalyst A comprises at least one element selected from Group 2 elements (excluding strontium) and Group 3 elements. A method for producing a cyclohexanedicarboxylic acid compound, wherein the nuclear hydrogenation catalyst B comprises at least one selected from a ruthenium-containing catalyst and a platinum-supported catalyst in which platinum is supported on silica. [2] The method for producing a cyclohexanedicarboxylic acid compound according to [1], wherein the catalyst A comprises at least one metal selected from magnesium, calcium, barium, lanthanum, and cerium. [3] The method for producing a cyclohexanedicarboxylic acid compound according to [1], comprising catalyst A, at least one metal selected from magnesium and cerium. [4] A method for producing a cyclohexanedicarboxylic acid compound according to any one of [1] to [3], wherein the nuclear hydrogenation catalyst B contains ruthenium. [5] A method for producing a cyclohexanedicarboxylic acid compound according to any one of [1] to [4], wherein the solvent used in the exchange reaction is a primary alcohol. [6] The method for producing a cyclohexanedicarboxylic acid compound according to [5], wherein the primary alcohol is at least one selected from methanol, ethanol, and ethylene glycol. [7] A method for producing a cyclohexanedicarboxylic acid compound according to any one of [1] to [6], wherein the polymer containing a terephthalic acid skeleton containing an ester group or an amide group is a polymer derived from recycled resin. A method for producing cyclohexanedimethanol, comprising the step of reducing a cyclohexanedicarboxylic acid compound obtained by the manufacturing method described in any of [8][1] to [7]. A method for producing a polyester resin, comprising the step of polymerizing at least one selected from a cyclohexanedicarboxylic acid compound obtained by the production method described in any of [9][1] to [7] and cyclohexanedimethanol obtained by the production method described in [8]. A method for producing a polycarbonate resin, comprising the step of carrying out polymerization using cyclohexanedimethanol obtained by the manufacturing method described in

[10] [8]. [Effects of the Invention]

[0009] According to the present invention, a method for producing cyclohexanedicarboxylic acid compounds, such as DMCD, from polymers having a terephthalic acid skeleton can be provided that is simple, low-cost, and yields sufficient quantities. Furthermore, a method for producing cyclohexanedimethanol, polyester resins, and polycarbonate resins using the method for producing cyclohexanedicarboxylic acid compounds can be provided. [Modes for carrying out the invention]

[0010] [Method for producing cyclohexanedicarboxylic acid compounds] The present invention relates to a method for producing cyclohexanedicarboxylic acid compounds, which is a method for producing cyclohexanedicarboxylic acid or cyclohexanedicarboxylic acid esters. More specifically, it is a method for producing cyclohexanedicarboxylic acid or cyclohexanedicarboxylic acid esters such as dimethyl-1,4-cyclohexanecarboxylate (DMCD) by performing hydrocracking of a polymer having a terephthalic acid skeleton, such as polyethylene terephthalate (PET).

[0011] The method for producing cyclohexanedicarboxylic acid compounds of the present invention comprises the following step (i). (i) A polymer having a terephthalic acid skeleton containing an ester group or an amide group (hereinafter also referred to as "polymer P") is subjected to an exchange reaction of the ester group or the amide group with an alcohol or water in the presence of catalyst A and a nuclear hydrogenation reaction in the presence of catalyst A and nuclear hydrogenation catalyst B to obtain cyclohexanedicarboxylic acid or a cyclohexanedicarboxylic acid ester.

[0012] In step (i), cyclohexanedicarboxylic acid is obtained by performing an exchange reaction (hydrolysis) of the ester group of polymer P with water and a nuclear hydrogenation reaction. Cyclohexanedicarboxylic acid ester is obtained by performing an exchange reaction (alcoholysis) of the ester group of polymer P with an alcohol and a nuclear hydrogenation reaction. Cyclohexanedicarboxylic acid ester is obtained by performing an exchange reaction (alcoholysis) of the amide group of polymer P with an alcohol and a nuclear hydrogenation reaction.

[0013] Examples of polymer P having a terephthalic acid skeleton containing an ester group include polyester resins containing repeating units based on a dicarboxylic acid component containing terephthalic acid and repeating units based on a diol component. The ratio of terephthalic acid to the total mass of the dicarboxylic acid components constituting the polyester resin is not limited, but is preferably 10 mol% or more, more preferably 40 mol% or more, and even more preferably 80 mol% or more. The ratio of terephthalic acid to the total mass of the dicarboxylic acid components constituting the polyester resin may be 100 mol%.

[0014] Examples of polymer P having a terephthalic acid skeleton containing an amide group include polyamide resins containing repeating units based on a dicarboxylic acid component containing terephthalic acid and repeating units based on a diamine component. The ratio of terephthalic acid to the total mass of the dicarboxylic acid components constituting the polyamide resin is not limited, but is preferably 10 mol% or more, more preferably 40 mol% or more, and even more preferably 80 mol% or more. The ratio of terephthalic acid to the total mass of the dicarboxylic acid components constituting the polyamide resin may be 100 mol%.

[0015] Other dicarboxylic acids besides terephthalic acid are not particularly limited, and examples include isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, cyclohexanedicarboxylic acid, and franjicarboxylic acid. The other dicarboxylic acids used in the polyester resin may be one type or two or more types.

[0016] The diol component is not particularly limited, and examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-phenol, 1,4-cyclohexanediol, 1,4-benzenedimethanol, and 1,4-cyclohexanedimethanol. The diol component used in the polyester resin may be one type or two or more types.

[0017] The diamine component is not particularly limited, and examples include 1,6-hexanediamine, ethylenediamine, 1,1-diaminoethane, 1,2-propanediamine, 1,3-propanediamine, 1,3-butanediamine, 1,4-butanediamine, 1,5-pentanediamine, 2-methyl-1,5-diaminopentane, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,4-phenylenediamine, 1,4-cyclohexanediamine, 1,4-benzenedimethaneamine, and 1,4-cyclohexanedimethaneamine. The diamine component used in the polyamide resin may be one type or two or more types.

[0018] The polymer P containing ester groups used in step (i) is preferably a polymer derived from recycled resin, i.e., a polyester resin derived from waste plastic, in order to reduce the environmental impact. Specifically, for example, crushed or cut pieces of polyester resin products such as PET bottles, polypropylene terephthalate, polybutylene terephthalate (PBT), polycyclohexylenedimethylene terephthalate, polybutylene naphthate, polybutylene adipate terephthalate, polyethylene succinate terephthalate, polybutylene succinate terephthalate, and PCC can be used. In step (i), only polyester resin derived from waste plastic may be used, or a combination of polyester resin derived from waste plastic and virgin polyester resin may be used. Furthermore, polyester resin derived from waste plastic usually contains additives, and the waste plastic used in step (i) may also contain additives. In detail, examples of additives include pigments, dyes, ultraviolet absorbers, glass fibers, carbon fibers, etc.

[0019] Similarly, the polymer P containing amide groups used in step (i) is preferably a polymer derived from recycled resin, i.e., a polyamide resin derived from waste plastic, in order to reduce the environmental impact. Specifically, for example, crushed or cut pieces of polyamide resin products such as polyhexamethylene terephthalamide, polynonameethylene terephthalamide, polymethylpentamethylene terephthalamide, and polyp-phenylene terephthalamide can be used. In step (i), only polyamide resin derived from waste plastic may be used, or a combination of polyamide resin derived from waste plastic and virgin polyamide resin may be used. Furthermore, the polyamide resin derived from waste plastic may also contain the aforementioned additives.

[0020] In step (i), when an exchange reaction (alcohol decomposition) is carried out between the ester group or amide group of polymer P and an alcohol, an alcohol is used as the solvent. The alcohol used for alcohol decomposition may be a primary alcohol, a secondary alcohol, or a tertiary alcohol. The number of hydroxyl groups in the alcohol may be one or two or more.

[0021] Specific examples of alcohols used in alcohol decomposition include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, tert-butanol, ethylene glycol, 1,3-propanediol, propylene glycol, and 1,4-butanediol. Among these, primary alcohols are preferred due to their low steric hindrance and high reaction rates for transesterification and amide-transesterification, with at least one selected from methanol, ethanol, and ethylene glycol being more preferred, and methanol being particularly preferred. One alcohol may be used alone for alcohol decomposition, or two or more may be used in combination.

[0022] In step (i), when the exchange reaction (hydrolysis) between the ester group of polymer P and water is carried out, an aqueous solvent containing water is used as the solvent. The aqueous solvent may be water alone, or it may be a mixed solvent of water and an aqueous organic solvent. Examples of aqueous organic solvents include the alcohols exemplified as solvents used in alcohol decomposition. The aqueous organic solvents used in hydrolysis may be one type or two or more types.

[0023] Diluting polymer P allows transesterification to proceed efficiently; therefore, the amount of solvent used is preferably 50 parts by mass or more, and more preferably 300 parts by mass or more, per 100 parts by mass of polymer P. Increasing the concentration of polymer P can increase productivity per unit volume; therefore, the amount of solvent used is preferably 10,000 parts by mass or less, and more preferably 2,000 parts by mass or less, per 100 parts by mass of polymer P. The lower and upper limits of the amount of solvent used can be arbitrarily combined; for example, 50 to 10,000 parts by mass is preferred, and 300 to 2,000 parts by mass is more preferred.

[0024] In step (i), a specific catalyst A and nuclear hydrogenation catalyst B are used in combination. With this combination of catalyst A and nuclear hydrogenation catalyst B, the nuclear hydrogenation reaction proceeds sufficiently even in the presence of catalyst A, so there is no need to remove catalyst A by purification before nuclear hydrogenation. Therefore, cyclohexanedicarboxylic acid or cyclohexanedicarboxylic acid ester can be obtained simply, at low cost, and in sufficient yield.

[0025] Catalyst A is a catalyst for at least one exchange reaction selected from the exchange reactions of an ester group with an alcohol, an ester group with water, and an amide group with an alcohol, and comprises at least one element selected from Group 2 (excluding strontium) and Group 3 elements. However, Group 3 elements include lanthanides and actinides. In terms of improving the yield of cyclohexanedicarboxylic acid compounds, the metal contained in catalyst A is preferably at least one selected from magnesium, calcium, barium, lanthanum, and cerium, more preferably at least one selected from magnesium and cerium, even more preferably either magnesium or cerium, and particularly preferably magnesium.

[0026] Examples of catalyst A include metal oxides containing the aforementioned metal, metal hydroxides, metal acetates, and metal acetylacetonates. Specific examples include magnesium oxide, magnesium acetate, magnesium acetylacetonate, magnesium hydroxide, calcium oxide, calcium acetate, calcium acetylacetonate, calcium hydroxide, barium oxide, barium acetate, barium acetylacetonate, barium hydroxide, cerium(IV) oxide, cerium(III) acetate, cerium(III) acetylacetonate, cerium(IV) hydroxide, lanthanum(III) oxide, lanthanum(III) acetate, lanthanum(III) acetylacetonate, and lanthanum(III) hydroxide. Catalyst A may be used alone or in combination of two or more types.

[0027] In terms of facilitating the exchange reaction between an ester group or amide group and an alcohol or water, the amount of catalyst A used is preferably 0.01 parts by mass or more, and more preferably 0.05 parts by mass or more, per 100 parts by mass of polymer P. In terms of separating catalyst A from the final product, the amount of catalyst A used is preferably 20 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of polymer P. The lower and upper limits of the amount of catalyst A used can be arbitrarily combined, for example, preferably 0.01 to 20 parts by mass, and more preferably 0.05 to 5 parts by mass.

[0028] Nuclear hydrogenation catalyst B is a nuclear hydrogenation catalyst comprising at least one selected from a ruthenium-containing catalyst and a platinum-supported catalyst in which platinum is supported on silica. Nuclear hydrogenation catalyst B is preferably a ruthenium-containing catalyst in that it improves the yield of cyclohexanedicarboxylic acid compounds. The shape of the nuclear hydrogenation catalyst B is not particularly limited, and examples include powder, granules, and lumps.

[0029] As a catalyst containing ruthenium, a ruthenium-supported catalyst in which ruthenium is supported on a support is preferred. The support used in the ruthenium-supported catalyst is not particularly limited, and examples include oxides, carbon, nitrides, and carbides, with oxides or carbon being preferred. Examples of oxides include silica, alumina, ceria, titania, zirconia, niobia, silica-alumina, titania-zirconia, and ceria-zirconia. Examples of carbon include activated carbon, carbon black, graphite, and carbon nanotubes. Examples of nitrides include boron nitride, silicon nitride, and gallium nitride. Examples of carbides include silicon carbide and gallium carbide.

[0030] While there are no particular limitations on the specific surface area of ​​the support used in metal catalysts, it is generally 1 m², which allows for high dispersion of the metal on the support and enables sufficient catalytic activity. 2 / g or more, preferably 10m 2 Preferably 50m / g or more. 2 More preferably 2000 m² / g or more. In terms of effectively utilizing the pores that the carrier usually has, the specific surface area of ​​the carrier is 2000 m². 2 Preferably less than / g, and 1500m 2 Less than / g is more preferable. The lower and upper limits of the specific surface area of ​​the carrier can be arbitrarily combined, for example, 10 to 2000 m². 2 / g is preferred, and 50-1500m 2 / g is preferable. The specific surface area of ​​the carrier is measured by the BET method.

[0031] To ensure sufficient reactivity, the amount of metal supported by the nuclear hydrogenation catalyst B, which is the supported catalyst, is preferably 0.1% by mass or more, and more preferably 1% by mass or more, relative to the total mass of the carrier. To obtain activity commensurate with the amount used, the amount of metal supported is preferably 50% by mass or less, and more preferably 20% by mass or less, relative to the total mass of the carrier. The lower and upper limits of the amount of metal supported can be arbitrarily combined, for example, preferably 0.1 to 50% by mass, and more preferably 1 to 20% by mass. Nuclear hydrogenation catalyst B may be used alone or in combination of two or more types.

[0032] The reaction may be carried out in either a continuous or batch manner, and either a liquid-phase suspension reaction or a fixed-bed flow reaction can be employed as the reaction type. The amount of nuclear hydrogenation catalyst B used can be arbitrarily selected within a range that yields a practical reaction rate, depending on the conditions. In terms of facilitating the nuclear hydrogenation reaction, the amount of nuclear hydrogenation catalyst B used in a suspension bed reaction is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of polymer P. In terms of reducing catalyst costs, the amount of nuclear hydrogenation catalyst B used is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of polymer P. The lower and upper limits of the amount of nuclear hydrogenation catalyst B used can be arbitrarily combined, for example, 0.1 to 100 parts by mass is preferred, 1 to 50 parts by mass is more preferred, and 5 to 20 parts by mass is even more preferred. In terms of facilitating the nuclear hydrogenation reaction, the amount of nuclear hydrogenation catalyst B used in a fixed-bed reaction is preferably 20 parts by volume or more, more preferably 50 parts by volume or more, and even more preferably 80 parts by volume or more, per 100 parts by volume of the empty reactor column.

[0033] The exchange reaction between the ester or amide group of polymer P and alcohol or water in the presence of catalyst A (hydrolysis or alcoholic decomposition), and the nuclear hydrogenation reaction in the presence of catalyst A and nuclear hydrogenation catalyst B may be carried out in two steps or in a one-pot reaction. More specifically, catalyst A may be added to the reaction system to carry out hydrolysis or alcoholic decomposition, and then nuclear hydrogenation catalyst B may be added to carry out the nuclear hydrogenation reaction, or both catalyst A and nuclear hydrogenation catalyst B may be added to the reaction system to carry out hydrolysis or alcoholic decomposition and the nuclear hydrogenation reaction.

[0034] When hydrolysis or alcohol decomposition and nuclear hydrogenation are carried out in a one-pot reaction, the reaction temperature is preferably 140°C or higher, more preferably 160°C or higher, and even more preferably 180°C or higher, in order to ensure the reaction proceeds sufficiently. In order to prevent by-products from excessive reaction, the reaction temperature is preferably 280°C or lower, more preferably 260°C or lower, and even more preferably 240°C or lower. The lower and upper limits of the reaction temperature can be arbitrarily combined, for example, 140 to 280°C is preferred, and 160 to 260°C is more preferred. Note that the reaction temperature refers to the temperature of the reaction solution. The reactor used for the reaction can be a batch reactor, a fluidized bed reactor, or a fixed bed reactor. The reaction time for one-pot hydrolysis or alcohol decomposition and nuclear hydrogenation can be set as appropriate, for example, from 0.01 to 30 hours. Note that the reaction time in fluidized bed and fixed bed reactors refers to the residence time based on the empty column volume.

[0035] When hydrolysis or alcohol decomposition and nuclear hydrogenation are carried out in two stages, the reaction temperature for hydrolysis or alcohol decomposition is preferably 140°C or higher, more preferably 160°C or higher, and even more preferably 180°C or higher, in terms of ensuring the reaction proceeds smoothly. In terms of reducing the cost of the reactor and the heat transfer medium, the reaction temperature for hydrolysis or alcohol decomposition is preferably 280°C or lower, more preferably 260°C or lower, and even more preferably 240°C or lower. The lower and upper limits of the reaction temperature for hydrolysis or alcohol decomposition can be arbitrarily combined, for example, preferably 140 to 280°C, and more preferably 160 to 260°C. The reactor used for the reaction can be a batch reactor, a fluidized bed reactor, or a fixed bed reactor. The reaction time for hydrolysis or alcohol decomposition can be set as appropriate, for example, from 0.01 to 10 hours. Note that the reaction time in fluidized bed and fixed bed reactors refers to the residence time based on the volume of the empty column.

[0036] When hydrolysis or alcohol decomposition and nuclear hydrogenation are carried out in two steps, the reaction temperature for nuclear hydrogenation is preferably 80°C or higher, more preferably 120°C or higher, and even more preferably 140°C or higher, in order to ensure that the reaction proceeds sufficiently. In order to prevent by-products from excessive hydrogenation decomposition, the reaction temperature for nuclear hydrogenation is preferably 260°C or lower, more preferably 240°C or lower, and even more preferably 220°C or lower. The lower and upper limits of the reaction temperature for nuclear hydrogenation can be arbitrarily combined, for example, preferably 80 to 260°C, and more preferably 120 to 240°C.

[0037] Nuclear hydrogenation reactions can be carried out by contacting hydrogen with the decomposition products after hydrolysis or alcohol decomposition. For example, one method involves blowing hydrogen gas into a reaction system containing nuclear hydrogenation catalyst B, thereby replacing the gas phase with hydrogen gas. In terms of ensuring the reaction proceeds smoothly, the gauge pressure during the nuclear hydrogenation reaction is preferably 3 MPaG or higher, and more preferably 5 MPaG or higher. In terms of reducing the cost of the reactor and hydrogen, the gauge pressure during the nuclear hydrogenation reaction is preferably 15 MPaG or lower, and more preferably 12 MPaG or lower. The lower and upper limits of the gauge pressure during the nuclear hydrogenation reaction can be arbitrarily combined; for example, 3 to 15 MPaG is preferred, and 5 to 12 MPaG is more preferred. The reactor used for nuclear hydrogenation can be a batch reactor, a fluidized bed reactor, or a fixed-bed reactor. The reaction time for nuclear hydrogenation can be set as appropriate, for example, from 0.01 to 20 hours. Note that the reaction time in fluidized bed and fixed-bed reactors refers to the residence time based on the empty column volume.

[0038] In step (i), it is preferable to carry out the reaction while stirring the reaction mixture. In order to ensure that the reaction proceeds sufficiently, the stirring speed can be appropriately selected depending on the size and shape of the reactor, the size and shape of the impeller, etc.

[0039] The cyclohexanedicarboxylic acid or cyclohexanedicarboxylic acid ester obtained in step (i) can be purified by known methods such as filtration, distillation, or recrystallization, if necessary. For example, dimethyl-1,4-cyclohexanecarboxylate (DMCD), obtained by alcohol decomposition of polymer P having a terephthalic acid skeleton with methanol and subsequent nuclear hydrogenation, can be purified by distillation.

[0040] As described above, the method for producing cyclohexanedicarboxylic acid compounds of the present invention uses a combination of a specific catalyst A and a nuclear hydrogenation catalyst B, so that the nuclear hydrogenation reaction can proceed sufficiently even in the presence of catalyst A. Therefore, there is no need to remove catalyst A before nuclear hydrogenation, and cyclohexanedicarboxylic acid or cyclohexanedicarboxylic acid ester can be obtained simply, at low cost, and in sufficient yield.

[0041] [Method for producing cyclohexanedimethanol] The present invention provides a method for producing cyclohexanedimethanol, which utilizes a cyclohexanedicarboxylic acid compound obtained by the method for producing cyclohexanedicarboxylic acid compounds of the present invention described above to produce 1,4-cyclohexanedimethanol (CHDM). CHDM is useful because it can be used as a raw material for high-performance polyester resins.

[0042] The method for producing cyclohexanedimethanol according to the present invention can employ known methods, except that it uses a cyclohexanedicarboxylic acid compound obtained by the method for producing cyclohexanedicarboxylic acid compounds according to the present invention. The method for producing cyclohexanedimethanol according to the present invention includes the following step (ii). (ii) A step of reducing the cyclohexanedicarboxylic acid compound obtained by the method for producing the cyclohexanedicarboxylic acid compound of the present invention.

[0043] The method for reducing cyclohexanedicarboxylic acid compounds is not particularly limited, and known methods can be employed. For example, one method involves reducing a cyclohexanedicarboxylic acid compound by contacting it with hydrogen in the presence of a reduction catalyst to obtain CHDM.

[0044] Either a heterogeneous or homogeneous catalyst may be used as the reduction catalyst. The amount of reduction catalyst used can be arbitrarily selected within a range that allows for a practical reaction rate, depending on the conditions. For example, heterogeneous catalysts include copper-chromium, copper-zinc, ranny nickel, rhenium, rhenium-palladium and rhenium-germanium, and ruthenium-platinum-tin, while homogeneous catalysts include Ru-MACHO, [2-(di-tert-butylphosphinomethyl)-6-(diethylaminomethyl)pyridine]carbonylchlorohydrudoruthenium(II) and dichlorobis(2-(diphenylphosphino)ethylamine)ruthenium(II). Among these, copper-chromium or copper-zinc is preferred, and copper-zinc is even more preferred, from the viewpoint of ease of purification and ester selectivity. One type of reduction catalyst may be used alone, or two or more types may be used in combination.

[0045] [Method for manufacturing polyester resin] The present invention provides a method for producing polyester resin using at least one compound selected from the cyclohexanedicarboxylic acid compounds and CHDM obtained by the above-described production method of the present invention. More specifically, a polyester resin is produced using a dicarboxylic acid component containing at least one of cyclohexanedicarboxylic acid and cyclohexanedicarboxylic acid ester obtained by the production method of the present invention, and at least one of a diol component containing CHDM obtained by the production method of the present invention.

[0046] The method for producing the polyester resin of the present invention can employ known methods, except that it uses at least one of the cyclohexanedicarboxylic acid compound and CHDM obtained by the production method of the present invention. The method for producing the polyester resin of the present invention includes the following step (iii). (iii) A step of polymerizing at least one selected from the cyclohexanedicarboxylic acid compound and CHDM obtained by the production method of the present invention.

[0047] For example, one method can be described as performing either an esterification reaction or a transesterification reaction, or both, using a dicarboxylic acid component and a diol component, followed by a polycondensation reaction under reduced pressure. Reaction conditions such as reaction temperature and reaction time can be set as appropriate.

[0048] Other dicarboxylic acid components besides the cyclohexanedicarboxylic acid compounds obtained by the manufacturing method of the present invention may be used in the production of polyester resins. Examples of other dicarboxylic acid components include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and their derivatives.

[0049] Other diol components besides CHDM obtained by the manufacturing method of the present invention may be used in the production of polyester resin. Examples of other diol components include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

[0050] Polyester resin is preferably manufactured in the presence of a catalyst. The catalyst is not particularly limited, and examples include metal compounds containing germanium, titanium, zirconium, hafnium, antimony, tin, magnesium, calcium, zinc, aluminum, cobalt, lead, cesium, manganese, lithium, potassium, sodium, copper, barium, cadmium, etc.

[0051] [Method for manufacturing polycarbonate resin] The present invention relates to a method for producing polycarbonate resin, which involves using CHDM obtained by the above-described method of the present invention to produce polycarbonate resin. The method for producing the polycarbonate resin of the present invention can employ known methods, except that it uses CHDM obtained by the production method of the present invention. The method for producing the polycarbonate resin of the present invention includes the following step (iv). (iv) A step of carrying out polymerization using CHDM obtained by the manufacturing method of the present invention.

[0052] For example, one method involves reacting a dihydroxy compound containing CHDM obtained by the production method of the present invention with a diester carbonate in the presence of a polymerization catalyst. Reaction conditions such as reaction temperature and reaction time can be set as appropriate.

[0053] For the production of polycarbonate resin, dihydroxy compounds other than CHDM obtained by the production method of the present invention may be used. Examples include alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure.

[0054] The polymerization catalyst is not particularly limited, and examples include alkali metal compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium bicarbonate, and potassium bicarbonate, as well as alkaline earth metal compounds such as calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium bicarbonate, magnesium bicarbonate, and strontium bicarbonate.

[0055] It should be noted that the present invention is not limited to the embodiments described above, and it is possible to replace the components in the embodiments with well-known components as long as it does not depart from the spirit of the present invention, and the modifications described above may be combined as appropriate. [Examples]

[0056] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0057] [Abbreviation] The abbreviations are as follows: PET-1: Polyethylene terephthalate (manufactured by Mitsubishi Chemical Corporation, product name: Novapex BK2180) PET-2: Crushed commercially available PET bottles PET-3: Cut pieces of commercially available PET bottles, less than 10mm in size, made by cutting them with scissors. PBT: Polybutylene terephthalate (Merck KGaA, Sigma-Aldrich product) N-PBT: Polybutylene terephthalate (Mitsubishi Engineering Plastics Corporation, product name: Novaduran 5010G30 / BK2) PBST: Butanediol-succinic acid-terephthalic acid copolymer (actual product from Thailand) PCT: Cyclohexanediol-terephthalic acid copolymer (SK Chemical, product name: SKYPURA 0502HC) Ru / C: Catalyst consisting of 5% by mass of ruthenium particles supported on activated carbon (N.E. Chemcat Co., Ltd.) Ru / Al2O3: A catalyst in which 5% by mass of ruthenium particles are supported on alumina (N.E. Chemcat Co., Ltd.) Pt / SiO2: A catalyst in which 5% by mass of platinum particles are supported on silica (lab-prepared product). Pd / C: Catalyst consisting of 5% by mass of palladium particles supported on activated carbon (N.E. Chemcat Co., Ltd.) Pd / Al2O3: A catalyst in which 5% by mass of palladium particles are supported on alumina (N.E. Chemcat Co., Ltd.) Pt / C: Catalyst consisting of 5% by mass of platinum particles supported on activated carbon (N.E. Chemcat Co., Ltd.) Rh / C: Catalyst consisting of 5% by mass of rhodium particles supported on activated carbon (N.E. Chemcat Co., Ltd.) MeOH: Methanol (Fujifilm Wako Pure Chemical Corporation) Mg acetate: Magnesium acetate (Fujifilm Wako Pure Chemical Corporation) Mg(acac)2: Magnesium acetylacetonate (Tokyo Chemical Industries, Ltd.) Zn acetate: Zinc acetate (Fujifilm Wako Pure Chemical Corporation) EG: Ethylene glycol DMCD: Dimethyl-1,4-cyclohexanecarboxylate CHDM: 1,4-Cyclohexanedimethanol DMT: Dimethyl terephthalate BHEC: Bis(2-hydroxyethyl) 1,4-cyclohexanedicarboxylate

[0058] [Yield] The yields of each component in the products of each example subjected to alcoholysis and hydrogenation were measured using gas chromatography (GC). The yields of each component in the products of the examples subjected to hydrolysis and hydrogenation were measured using liquid chromatography (LC).

[0059] [ Intrinsic viscosity of polyester ] It was determined in the following manner using an automatic viscometer (model DT553, capillary type) manufactured by Sentec Co., Ltd. That is, a mixed solution of PTM11 (a mixture of phenol and 1,1,2,2-tetrachloroethane with a mass ratio of 1 / 1) was used as a solvent, and at 30 °C, the dropping seconds of a sample solution with a concentration of 1.0 g / dL and only the solvent were measured, and it was determined from the following formula. Intrinsic viscosity (dL / g) = ((1 + 4K H η sp )) 0.5 -1) / (2K H C) (However, η sp = η / η0 - 1, where η is the dropping seconds of the sample solution, η0 is the dropping seconds of the solvent, C is the sample solution concentration (g / dL), and K H is the Huggins constant. K H was adopted as 0.33.)

[0060] [Example 1] Into an autoclave equipped with a stirrer, 0.50 g (100 parts by mass) of PET-1, 10.0 g (2000 parts by mass) of MeOH, 5 mg of magnesium oxide (MgO) as a catalyst A at 1% by mass based on the amount of PET-1 used, and 0.10 g of Ru / C as a hydrogenation catalyst B at 20% by mass based on the amount of PET-1 used were placed. The gas phase in the autoclave was replaced with hydrogen gas to set the gauge pressure to 5 MPaG. The autoclave was heated to 200°C while stirring at 600 rpm using a stirrer, and the reaction was carried out for 6 hours. After the heater was turned off and the autoclave was cooled to room temperature, the reactants were removed, and the catalyst was separated by filtration to obtain the product. The yields of EG, DMCD, DMT, and BHEC in the product are shown in Table 1.

[0061] [ka]

[0062] [Examples 2-14] The product was obtained in the same manner as in Example 1, except that the type and amount of transesterification catalyst (1) used were changed as shown in Table 1. The yields of EG, DMCD, DMT, and BHEC in the product are shown in Table 1.

[0063] In Table 1, the amounts of transesterification catalyst (1) and nuclear hydrogenation catalyst (2) used are expressed as a percentage (mass%) of the amount of substrate PET-1 used. The yields of EG, DMCD, DMT, and BHEC are expressed as a percentage (mol%) of the amount of terephthalic acid (TPA) units of substrate PET-1. Furthermore, for BHEC, (1) and (2) are either the cis or trans isomer. These notations are consistent throughout the other tables.

[0064] [Table 1]

[0065] As shown in Table 1, in Examples 1-8, where PET was decomposed with alcohol and then nuclear hydrogenated in the presence of catalyst A and nuclear hydrogenation catalyst B, DMCD was obtained in higher yields compared to Examples 9-14, which used transesterification catalysts other than catalyst A. Furthermore, the yield of DMCD was particularly high in Examples 1-4 and 7, which used catalyst A containing magnesium or cerium.

[0066] [Examples 15-20] The product was obtained in the same manner as in Example 1, except that the type and amount of nuclear hydrogenation catalyst (2) used were changed as shown in Table 2. The yields of EG, DMCD, DMT, and BHEC in the product are shown in Table 2.

[0067] [Table 2]

[0068] As shown in Table 2, in Examples 1, 15, and 16, where PET was decomposed with alcohol in the presence of catalyst A and nuclear hydrogenation catalyst B, DMCD was obtained in higher yields compared to Examples 17-20, where nuclear hydrogenation catalysts other than nuclear hydrogenation catalyst B were used.

[0069] [Examples 21-22, 28-31] The product was obtained in the same manner as in Example 1, except that PET-2, PBT, N-PBT, PBST, or PCTPET-3 were used instead of PET-1. The yields of EG, DMCD, DMT, and BHEC in the product are shown in Table 3.

[0070] [Table 3]

[0071] As shown in Table 3, in Examples 21 and 22, which used crushed or cut PET bottles (assuming they were derived from recycled resin) as raw materials, DMCD was obtained in high yield by alcohol decomposition of PET in the presence of catalyst A and nuclear hydrogenation catalyst B, followed by nuclear hydrogenation, similar to Example 1. Furthermore, in Examples 28-31, which used resins with a terephthalic acid skeleton other than PET as raw materials, DMCD was obtained in high yield by alcohol decomposition of the resin in the presence of catalyst A and nuclear hydrogenation catalyst B, followed by nuclear hydrogenation, similar to Example 1.

[0072] [Example 23] The product was obtained in the same manner as in Example 1, except that a transesterification catalyst was not used. The yields of EG, DMCD, DMT, and BHEC in the product are shown in Table 4.

[0073] [Example 24] The product was obtained in the same manner as in Example 1, except that the type of nuclear hydrogenation catalyst B was changed as shown in Table 4 and a transesterification catalyst was not used. The yields of EG, DMCD, DMT, and BHEC in the product are shown in Table 4.

[0074] [Table 4]

[0075] As shown in Table 4, in Examples 23 and 24, where a transesterification catalyst was not used, the yield of DMCD was lower compared to Example 1.

[0076] [Example 25, Scaling Up and Generation Example] In an autoclave equipped with a stirrer, 60.00 g (100 parts by mass) of PET-1, 90.00 g (150 parts by mass) of MeOH, 0.15 g of magnesium oxide (MgO) as catalyst A (0.25% by mass relative to the amount of PET-1 used), and 1.50 g of Ru / C as nuclear hydrogenation catalyst B (2.5% by mass relative to the amount of PET-1 used) were added. The gas phase inside the autoclave was replaced with hydrogen gas to a gauge pressure of 1 MPaG. The autoclave was heated to 185°C while stirring at 750 rpm using a stirrer, and hydrogen gas was introduced until the gauge pressure reached 10 MPaG. The temperature was then raised to 200°C, and the reaction was carried out for 10 hours. After the heater was turned off and the autoclave was cooled to room temperature, the reactants were removed, and the catalyst was separated by filtration to obtain the crude product. To the crude product, 100 mL of ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was washed three times with 100 mL of water. After removing the solvent by distillation, 30.92 g of DMCD was obtained by vacuum distillation at 0.5 kPa and 127-130°C.

[0077] [Example 26: Example of polyester resin manufacturing] In a transesterification reactor equipped with a stirrer, nitrogen inlet, heater, thermometer, and distillation tube, 58.1 parts by mass of DMCD obtained in Example 25, 41.9 parts by mass of CHDM (cis / trans isomer = 3 / 7, manufactured by Hisho Group), and tetrabutyl titanate (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a catalyst were added as a solution of butanol at a concentration of 61 ppm by mass relative to the polymer to be produced, calculated on a titanium metallic basis. The temperature of the liquid in the reactor was then raised from 150°C to 210°C over 90 minutes, and then maintained at 210°C for 30 minutes. During this time, the resulting methanol was distilled off, and the transesterification reaction was carried out for a total of 120 minutes.

[0078] After the transesterification reaction was complete, tetrabutyl titanate in an amount equivalent to 33 ppm by mass of titanium metal was added to the resulting polymer as a solution of butanol, and then the polycondensation reaction was carried out under reduced pressure. The polycondensation reaction was carried out by gradually reducing the pressure inside the tank from atmospheric pressure to 0.4 kPa over 85 minutes, and then maintaining the pressure below 0.4 kPa for 155 minutes. The temperature of the liquid inside the tank was raised from 210°C to 250°C over 60 minutes, and then maintained at 250°C for 180 minutes.

[0079] Next, the tank was repressurized with nitrogen after being under reduced pressure, and then pressurized for polymer extraction. The heat transfer medium temperature at the nozzle was set to 250°C, and the polymer was extruded from the nozzle in strand form. After cooling the strands in a cooling water tank, they were cut with a strand cutter and pelletized. The intrinsic viscosity of the obtained polycyclohexylcyclohexylate was 0.54 dL / g.

[0080] As shown in Example 25, the DMCD produced by this method can be purified by distillation, and as shown in Example 26, it has been shown that it can be used as a raw material for polyester resin.

[0081] [Example 27] The product was obtained in the same manner as in Example 1, except that the solvent was changed from MeOH to water. As a result, the yield of cyclohexanedicarboxylic acid was 30.3%. Thus, even in the case of hydrolysis, the nuclear hydrogenation reaction proceeded sufficiently in the presence of catalyst A and nuclear hydrogenation catalyst B.

[0082] [Example 32: Example of cyclohexanedimethanol production] In a 70 mL spinner-type autoclave, 1.50 g (100 parts by mass) of DMCD obtained in Example 25, 3.5 g (233 parts by mass) of tetrahydrofuran, and 0.15 g of CuO / ZnO / Al2O3 catalyst [JGC Catalyst E01X], which had been pre-reduced at 300°C for 2 hours under a hydrogen flow, were placed. The gas phase inside the autoclave was replaced with hydrogen gas to set the gauge pressure to 5 MPaG. The temperature inside the autoclave was raised to 250°C while stirring at 600 rpm using a stirrer, and the reaction was carried out for 6 hours. After turning off the heater and cooling the autoclave to room temperature, the reactants were removed, and the catalyst was separated by filtration to obtain cyclohexanedimethanol (CHDM). The results are shown in Table 5.

[0083] [Example 33: Example of cyclohexanedimethanol production] In Example 25, DMCD was obtained using the same method as in Example 32, except that the raw material PET-1 was changed to PBT and distillation purification after washing of the crude product was omitted. The results are shown in Table 5.

[0084] [Table 5]

[0085] As shown in Table 5, CHDM was obtained with high efficiency using DMCD produced by this method.

Claims

1. The process includes obtaining cyclohexanedicarboxylic acid or a cyclohexanedicarboxylic acid ester by performing an exchange reaction between the ester group or amide group and an alcohol or water in the presence of catalyst A, and a nuclear hydrogenation reaction in the presence of catalyst A and nuclear hydrogenation catalyst B, on a polymer having a terephthalic acid skeleton containing an ester group or an amide group. The catalyst A is a group 2 element (excluding strontium). ) and at least one element selected from Group 3 elements, A method for producing a cyclohexanedicarboxylic acid compound, wherein the nuclear hydrogenation catalyst B comprises at least one selected from a ruthenium-containing catalyst and a platinum-supported catalyst in which platinum is supported on silica.

2. The method for producing a cyclohexanedicarboxylic acid compound according to claim 1, wherein the catalyst A comprises at least one metal selected from magnesium, calcium, barium, lanthanum, and cerium.

3. The method for producing a cyclohexanedicarboxylic acid compound according to claim 1, wherein the catalyst A comprises at least one metal selected from magnesium and cerium.

4. The method for producing a cyclohexanedicarboxylic acid compound according to claim 1, wherein the nuclear hydrogenation catalyst B contains ruthenium.

5. The method for producing a cyclohexanedicarboxylic acid compound according to claim 1, wherein the solvent used in the exchange reaction is a primary alcohol.

6. The method for producing a cyclohexanedicarboxylic acid compound according to claim 5, wherein the primary alcohol is at least one selected from methanol, ethanol, and ethylene glycol.

7. The method for producing a cyclohexanedicarboxylic acid compound according to claim 1, wherein the polymer containing the terephthalic acid skeleton that includes the ester group or amide group is a polymer derived from recycled resin.

8. A method for producing cyclohexanedimethanol, comprising the steps of obtaining a cyclohexanedicarboxylic acid compound by a manufacturing method described in any one of claims 1 to 7, and reducing the cyclohexanedicarboxylic acid compound.

9. A method for producing a polyester resin, comprising the steps of: obtaining a cyclohexanedicarboxylic acid compound by the production method described in any one of claims 1 to 7 or obtaining cyclohexanedimethanol by the production method described in claim 8; and polymerizing at least one selected from the cyclohexanedicarboxylic acid compound or cyclohexanedimethanol.

10. A method for producing a polycarbonate resin, comprising the steps of obtaining cyclohexanedimethanol by the manufacturing method described in claim 8, and carrying out polymerization using the cyclohexanedimethanol.

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