A copper-based ester hydrogenation catalyst, a preparation method and application thereof, and a preparation method of 1,4-cyclohexanedimethanol

Abstract

The application provides a copper-based ester hydrogenation catalyst and a preparation method and application thereof, and a preparation method of 1,4-cyclohexanedimethanol, and belongs to the field of catalytic chemistry. The method comprises the following steps: mixing a soluble copper salt, a metal additive soluble salt, an alkaline substance and water to carry out a precipitation reaction to obtain a hydroxide precipitate; mixing the hydroxide precipitate with a pore expanding agent and then maintaining to obtain a mixture; and sequentially carrying out water washing, drying and calcination on the mixture to obtain the copper-based ester hydrogenation catalyst. The copper-based ester hydrogenation catalyst with high pore diameter and high specific surface area is prepared by mixing the pore expanding agent with the alkaline substance to expand the pores, and the catalyst is particularly suitable for preparing CHDM by hydrogenating 1,4-cyclohexanedimethyl acid dimethyl ester, and CHDM with a trans ratio of more than 75% can be obtained at a lower temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalytic chemistry, and particularly relates to a copper-based ester hydrogenation catalyst, a preparation method and application thereof, and a preparation method of 1,4-cyclohexanedimethanol. BACKGROUND

[0002] 1,4-cyclohexanedimethanol (CHDM) is widely used as a raw material for medicines, epoxy resins, synthetic polyesters or synthetic fibers, and particularly used as a raw material for environmentally friendly PETG. The polyester product synthesized therefrom has better thermal stability, transparency, impact resistance, wear resistance and corrosion resistance than ordinary polyester resins (PET, PBT) and the like.

[0003] At present, the only process that has realized industrialization in the world is a dimethyl terephthalate method (DMT method), and both Eastman and SK of South Korea produce CHDM through the DMT method. In the first step, dimethyl terephthalate is subjected to hydrogenation of a benzene ring to generate dimethyl cyclohexanedicarboxylate (DMCD), and in the second step, CHDM is prepared by hydrogenation of an ester group of DMCD. For the hydrogenation of the ester group of DMCD in the second step, how to prepare CHDM with high activity, high selectivity and high cis-trans ratio has become a research hotspot. SUMMARY

[0004] In view of this, the present application aims to provide a copper-based ester hydrogenation catalyst, a preparation method and application thereof, and a preparation method of 1,4-cyclohexanedimethanol. The copper-based ester hydrogenation catalyst provided by the present application can realize the preparation of CHDM with high activity, high selectivity and high cis-trans ratio.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides a preparation method of a copper-based ester hydrogenation catalyst, comprising the following steps:

[0007] The soluble copper salt, the metal additive soluble salt, the alkaline substance and water are mixed to perform a precipitation reaction, so as to obtain a hydroxide precipitate;

[0008] The hydroxide precipitate is mixed with a pore-expanding agent and then maintained, so as to obtain a mixed material;

[0009] The mixed material is sequentially subjected to water washing, drying and calcination, so as to obtain the copper-based ester hydrogenation catalyst.

[0010] Preferably, the metal elements in the metal additive soluble salt include one or more of manganese, zinc, aluminum, magnesium, nickel, tin, chromium and iron.

[0011] Preferably, the molar ratio of the metal elements in the metal additive soluble salt to the copper elements in the soluble copper salt is 0-2:1, and the molar amount of the metal elements is not 0.

[0012] Preferably, the reaming agent comprises one or more of polymethyl methacrylate microspheres, polyethylene glycol microspheres, polyvinyl alcohol microspheres, naphthalene, ammonium bicarbonate and hydrogen peroxide.

[0013] Preferably, the calcination is programmed heating, which is: within 1h, from room temperature to 60-120℃, holding for 4-6h, then within 4-8h, increasing to 220-320℃, holding for 4-6h, and finally within 4-8h, increasing to 500-650℃, holding for 4-6h.

[0014] The application also provides a copper-based ester hydrogenation catalyst prepared by the preparation method, which comprises copper oxide and metal promoter oxide.

[0015] The application also provides application of the copper-based ester hydrogenation catalyst in preparation of 1,4-cyclohexanedimethanol from 1,4-cyclohexanedimethyl ester.

[0016] The application also provides a preparation method of 1,4-cyclohexanedimethanol, comprising the following steps:

[0017] hydrogenation catalyst to perform a hydrogenation reaction to obtain 1,4-cyclohexanedicarboxylic acid;

[0018] mixing the 1,4-cyclohexanedicarboxylic acid with methanol to perform an esterification reaction to obtain 1,4-cyclohexanedimethyl ester;

[0019] mixing the 1,4-cyclohexanedimethyl ester with an ester hydrogenation catalyst to perform an ester hydrogenation reaction to obtain the 1,4-cyclohexanedimethanol, and the ester hydrogenation catalyst is the copper-based ester hydrogenation catalyst according to the above technical solution.

[0020] Preferably, the ester hydrogenation reaction is performed at a temperature of 180-240℃, a reaction pressure of 2-6MPa, a hydrogen / ester molar ratio of 100-300:1, and a feed air speed of 0.05-0.5h -1 .

[0021] Preferably, the esterification reaction further comprises the following steps: rectifying the obtained esterification product through a demethanolization tower to obtain light components and tower bottom material, the light components are recycled for esterification reaction, and the tower bottom material is rectified and purified through a 1,4-cyclohexanedimethyl ester rectification tower to obtain the 1,4-cyclohexanedimethyl ester and tower bottom liquid, and the tower bottom liquid is recycled for esterification reaction.

[0022] The application provides a preparation method of a copper-based ester hydrogenation catalyst, which comprises the following steps: mixing a soluble copper salt, a metal additive soluble salt, an alkaline substance and water to perform a precipitation reaction to obtain a hydroxide precipitate; mixing the hydroxide precipitate with a pore expanding agent and then preserving to obtain a mixture; and sequentially performing water washing, drying and calcination on the mixture to obtain the copper-based ester hydrogenation catalyst.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The copper-based ester hydrogenation catalyst with high pore diameter and high specific surface area is prepared by mixing the pore expanding agent with the alkaline substance, and the catalyst is particularly suitable for preparing CHDM by hydrogenating 1,4-cyclohexane dimethyl ester, and CHDM with a trans ratio of more than 75% can be obtained at a lower temperature.

[0025] The application also provides a preparation method of 1,4-cyclohexane dimethyl alcohol, which is prepared from PTA through hydrogenation reaction, esterification reaction and ester hydrogenation reaction. The method uses PTA as a raw material to replace DMT, reduces the production cost, and realizes the continuous production of 1,4-cyclohexane dimethyl alcohol prepared from PTA through process innovation, and is a preparation method of a high-trans-ratio CHDM catalyst. DETAILED DESCRIPTION

[0026] The application provides a preparation method of a copper-based ester hydrogenation catalyst, which comprises the following steps:

[0027] The soluble copper salt, the metal additive soluble salt, the alkaline substance and water are mixed to perform a precipitation reaction to obtain a hydroxide precipitate.

[0028] The hydroxide precipitate is mixed with a pore expanding agent and then preserved to obtain a mixture.

[0029] The mixture is sequentially subjected to water washing, drying and calcination to obtain the copper-based ester hydrogenation catalyst.

[0030] In the application, the raw materials used are all commercially available products in the field unless otherwise specified.

[0031] The soluble copper salt, the metal additive soluble salt, the alkaline substance and water are mixed to perform a precipitation reaction to obtain a hydroxide precipitate.

[0032] In the application, the soluble copper salt is preferably copper nitrate, copper chloride or copper sulfate.

[0033] In the application, the metal elements in the metal additive soluble salt preferably include one or more of manganese, zinc, aluminum, magnesium, nickel, tin, chromium and iron.

[0034] In the present application, the metal auxiliary soluble salt is preferably nitrate, sulfate, oxalate, acetate or hydrochloride.

[0035] In the present application, the molar ratio of the metal element in the metal auxiliary soluble salt to the copper element in the soluble copper salt is preferably 0-2:1, and the molar amount of the metal element is not 0.

[0036] In the present application, the basic substance is preferably mixed in the form of a basic substance aqueous solution, and the basic substance preferably includes sodium hydroxide.

[0037] In the present application, the mixed aqueous solution of the soluble copper salt and the metal auxiliary soluble salt is preferably added to the basic substance aqueous solution.

[0038] In the present application, the temperature of the precipitation reaction is preferably 25-80℃, more preferably 40-60℃, and the time is preferably 4-12h, more preferably 6-10h.

[0039] After the precipitation reaction is completed, the obtained precipitation system is preferably filtered and washed with water to obtain the hydroxide precipitate. The present application does not have special limitations on the specific method of the filtration and water washing.

[0040] After obtaining the hydroxide precipitate, the present application mixes the hydroxide precipitate with a pore-expanding agent and preserves it to obtain a mixed material.

[0041] In the present application, the pore-expanding agent preferably includes one or more of polymethyl methacrylate microspheres (PMMA), polyethylene glycol microspheres, polyvinyl alcohol (PVA) microspheres, naphthalene, ammonium bicarbonate and hydrogen peroxide.

[0042] In the present application, the hydrogen peroxide is preferably added in the form of hydrogen peroxide, and the mass concentration of the hydrogen peroxide is preferably 25-50%.

[0043] In the present application, the naphthalene is preferably an industrial naphthalene ball.

[0044] In the present application, the mass ratio of the hydroxide precipitate to the pore-expanding agent is preferably 0.1-10:1.

[0045] In the present application, the temperature of the preservation is preferably 40-70℃, more preferably 50-60℃, and the time is preferably 6-10h.

[0046] After obtaining the mixed material, the present application sequentially performs water washing, drying and calcination on the mixed material to obtain the copper-based ester hydrogenation catalyst.

[0047] In the present application, the drying is preferably baking, the temperature of the baking is preferably 60-90℃, more preferably 70℃, and the time is preferably 4-6h.

[0048] In this invention, the roasting is preferably a programmed temperature rise, which is preferably: raising the temperature from room temperature to 60-120°C within 1 hour, more preferably 90-110°C, and holding it for 4-6 hours; then raising the temperature to 220-320°C within 4-8 hours, more preferably 250-300°C, and holding it for 4-6 hours; and finally raising the temperature to 500-650°C within 4-8 hours, more preferably 550-600°C, and holding it for 4-6 hours.

[0049] In this invention, the roasting is preferably carried out in a muffle furnace.

[0050] The present invention also provides a copper-based ester hydrogenation catalyst prepared by the preparation method described above, comprising copper oxide and metal auxiliary oxide.

[0051] This invention also improves the application of the copper-based ester hydrogenation catalyst described in the above technical solution in the preparation of 1,4-cyclohexanediethanol from 1,4-cyclohexanedimethyl ester.

[0052] This invention also provides a method for preparing 1,4-cyclohexanediethanol, comprising the following steps:

[0053] The hydrogenation reaction was carried out by mixing terephthalic acid (PTA) with a hydrogenation catalyst to obtain 1,4-cyclohexanedicarboxylic acid;

[0054] The 1,4-cyclohexanedicarboxylic acid was mixed with methanol and subjected to an esterification reaction to obtain 1,4-cyclohexanedimethyl ester;

[0055] The 1,4-cyclohexanedimethyl ester was mixed with an ester hydrogenation catalyst to carry out an ester hydrogenation reaction, thereby obtaining the 1,4-cyclohexanediethanol. The ester hydrogenation catalyst was the copper-based ester hydrogenation catalyst described in the above technical solution.

[0056] This invention involves mixing terephthalic acid (PTA) and a hydrogenation catalyst to perform a hydrogenation reaction, yielding 1,4-cyclohexanedicarboxylic acid (CHDA).

[0057] In this invention, the hydrogenation catalyst is preferably a palladium-carbon catalyst, a platinum-carbon catalyst, or a ruthenium-carbon catalyst. The mass content of the active component in the hydrogenation catalyst is preferably 1-10%, more preferably 5%. The carbon support in the hydrogenation catalyst is preferably coconut shell carbon, powdered carbon, granular carbon, or carbon nanotubes.

[0058] In this invention, the amount of the hydrogenation catalyst is preferably 0.5 to 5% of the mass of terephthalic acid.

[0059] In this invention, the hydrogenation reaction is preferably carried out in a hydrogenation reactor, which is preferably a loop reactor or multiple reactors connected in series.

[0060] In the present application, the temperature of the hydrogenation reaction is preferably 160-220°C, more preferably 170-180°C, the pressure is preferably 4-10 MPa, more preferably 5-6 MPa, and the time is preferably 4-10 h.

[0061] In the present application, the terephthalic acid is preferably mixed in the form of a PTA aqueous solution with a mass concentration of 10-50%, and the water in the PTA aqueous solution is preferably fresh water or recycled condensate water, and the source of the condensate water is described in subsequent steps.

[0062] In the present application, the hydrogenation catalyst is preferably fresh hydrogenation catalyst or recycled hydrogenation catalyst.

[0063] In specific embodiments of the present application, fresh water or recycled condensate water is used to pump fresh hydrogenation catalyst or recycled hydrogenation catalyst from the filter to the hydrogenation mixing kettle, PTA is fed into the hydrogenation mixing kettle by a screw conveyor, and after uniform mixing and preheating, the material is pumped into the hydrogenation reactor by a high-pressure pump to perform the hydrogenation reaction, thereby obtaining a 1,4-cyclohexane dicarboxylic acid aqueous solution, which is preferably mixed with the DMCD rectification column bottom liquid and then fed into a dehydration tower for dehydration, and the mixed liquid after dehydration is pumped into an esterification reactor to perform the esterification reaction.

[0064] In the present application, the mass of the DMCD rectification column bottom liquid is preferably 10-30% of the mass of the 1,4-cyclohexane dicarboxylic acid.

[0065] In the present application, the temperature of the dehydration in the dehydration tower is preferably 140-220°C, the pressure is preferably atmospheric pressure, and the time is preferably until the water is completely removed.

[0066] After obtaining the 1,4-cyclohexane dicarboxylic acid, the present application mixes the 1,4-cyclohexane dicarboxylic acid with methanol to perform an esterification reaction, thereby obtaining 1,4-cyclohexane dimethyl ester.

[0067] In the present application, the temperature of the esterification reaction is preferably 120-200°C, more preferably 180-190°C, the pressure is preferably 2.7-3.3 MPa, and the time is preferably 30 min-6 h, and the esterification reactor of the esterification reaction is preferably a single reactor, two reactors in series, or multiple reactors in series, and further preferably, when two reactors or multiple reactors in series are used, a flash tank is added between the two reactors to remove the water generated in the esterification reaction, and the flash temperature of the flash tank is preferably 100-120°C, and the flash pressure is preferably -0.1 to -0.095 MPa.

[0068] In the present application, the esterification reaction is preferably followed by the steps of: rectifying the obtained esterification product through a demethanolization tower to remove methanol and water, obtaining light components (methanol) which are recycled to the esterification reaction, and a tower bottom material which is rectified and purified through a 1,4-cyclohexane dimethyl ester rectification tower (DMCD rectification tower) to obtain the 1,4-cyclohexane dimethyl ester and a tower bottom liquid which is recycled to the esterification reaction and mixed with the 1,4-cyclohexane dicarboxylic acid aqueous solution.

[0069] After obtaining the 1,4-cyclohexane dimethyl ester, the 1,4-cyclohexane dimethyl ester is mixed with an ester hydrogenation catalyst to perform an ester hydrogenation reaction to obtain the 1,4-cyclohexane dimethyl alcohol, and the ester hydrogenation catalyst is the copper-based ester hydrogenation catalyst described in the above technical solution.

[0070] In the present application, the 1,4-cyclohexane dimethyl ester preferably enters a hydrogenation reactor after being vaporized and superheated to perform the ester hydrogenation reaction under the action of the ester hydrogenation catalyst.

[0071] In the present application, the temperature of the ester hydrogenation reaction is preferably 180-240°C, more preferably 200-230°C, and most preferably 220°C, the reaction pressure is preferably 2-6 MPa, more preferably 4-4.5 MPa, and most preferably 3-3.5 MPa, the hydrogen-ester molar ratio is preferably 100-300:1, more preferably 200-300:1, and the feed air speed is preferably 0.05-0.5 h -1 , more preferably 0.1-0.2 h -1 .

[0072] After the ester hydrogenation reaction is completed, the present application preferably sequentially subjects the obtained product to condensation, gas-liquid separation, and rectification and purification to obtain the 1,4-cyclohexane dimethyl alcohol, and the present application does not have special limitations on the specific parameters of the condensation, gas-liquid separation, and rectification and purification.

[0073] In order to further illustrate the present application, the copper-based ester hydrogenation catalyst and the preparation method and application thereof and the preparation method of 1,4-cyclohexane dimethyl alcohol provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the protection scope of the present application.

[0074] Example 1

[0075] 1) 241.6 kg of copper nitrate trihydrate, 125.0 kg of aluminum nitrate nonahydrate, and 60.0 kg of zinc nitrate hexahydrate are weighed and dissolved in 10 kg of water to prepare a mixed salt aqueous solution for later use; 132.0 kg of sodium hydroxide is weighed and dissolved in 1500 kg of water to prepare an alkali solution for later use;

[0076] 2) The alkaline solution obtained in step 1) is transferred into a reaction kettle, stirred and heated to 40°C, and the mixed salt aqueous solution prepared in step 1) is added dropwise into the reaction kettle at a uniform speed within 3h, and after 3h of incubation, the mixture is filtered, and washed with water three times, each time using 1000kg of water;

[0077] 3) 10.0kg of PMMA microspheres are weighed and mixed with the filter cake obtained in step 2), and after 6h of incubation at 60°C, the mixture is extruded into strips using an extruder with a 4mm aperture to obtain strip-shaped materials;

[0078] 4) The strip-shaped materials obtained in step 3) are dried at 90°C for 4h, heated to 250°C for 4h, and then heated to 550°C for 6h for calcination, and then cooled to room temperature, cut into 3-5mm strip-shaped materials to obtain a copper-based ester hydrogenation catalyst CAT-01.

[0079] Application Example 1

[0080] 1) Fresh water / condensed water recovered from the dehydration tower is pumped at a flow rate of 12kg / h to backwash the fresh / circulating hydrogenation catalyst from the filter into the hydrogenation mixing kettle. The hydrogenation catalyst is a 2% palladium on carbon catalyst solution, and the content of palladium in the palladium on carbon catalyst is 5wt%. The PTA is fed into the hydrogenation mixing kettle by a screw conveyor (the conveying speed is 8kg / h), and after being uniformly mixed and preheated, the material is pumped into a three-kettle series hydrogenation reactor by a high-pressure pump. Under the conditions of 160°C and 6MPa hydrogen, the material is catalytically hydrogenated, filtered by a filter, and CHDA aqueous solution is prepared. The total average residence time of the reaction material in the three series hydrogenation reactors is 6h;

[0081] 2) The CHDA aqueous solution from step 1) is mixed with the bottom liquid from the DMCD rectification tower, and then dehydrated in the dehydration tower (the mass of the bottom liquid is 10% of the mass of the CHDA entering the dehydration tower). After dehydration, the CHDA mixture is pumped into an esterification reactor by a pump, and is esterified with methanol from the tank area (the flow rate is 10kg / h) under the conditions of 180°C and 2.7MPa (the total average residence time of the esterification material in the esterification reactor is 3h). After esterification, the material is subjected to a demethanolization tower to remove methanol and water, and the light components are recovered to the demethanolization tower to recover methanol. The bottom liquid is mixed with the CHDA aqueous solution from the PTA hydrogenation section and is subjected to the dehydration tower.

[0082] 3) 100kg of CAT-01 is weighed and loaded into a fixed bed reactor. The DMCD from step 2) is subjected to a vaporizer and a superheater, and then is subjected to an ester hydrogenation reaction in a hydrogenation reactor under the conditions of 220°C, 4.0MPa, and the action of the CAT-01 catalyst. After the reactor material is condensed, gas-liquid separated, and purified by rectification, high-trans CHDM is prepared. The reaction performance is shown in Table 1.

[0083] Example 2

[0084] 1) Take 241.6 kg of copper nitrate trihydrate, 250.0 kg of aluminum nitrate nonahydrate and 120.0 kg of zinc nitrate hexahydrate, dissolve in 10 kg of water to prepare a mixed salt aqueous solution for standby; take 132.0 kg of sodium hydroxide, dissolve in 1500 kg of water to prepare an alkali solution for standby;

[0085] 2) Transfer the alkali solution prepared in step 1) to the reaction kettle, stir and heat to 40℃, and add the mixed salt aqueous solution prepared in step 1) into the reaction kettle at a uniform speed within 3h, and keep for 3h, then filter, and wash with water for three times, each time with 1000 kg of water;

[0086] 3) Take 10.0 kg of industrial naphthalene microspheres, mix with the filter cake obtained in step 2) uniformly, keep at 70℃ for 6h, then extrude into strips by using an extruder to obtain strip-shaped materials, and the aperture of the extruder is 4mm;

[0087] 4) Dry the strip-shaped materials obtained in step 3) at 90℃ for 4h, then heat to 200℃ for 4h, keep for 4h, then heat to 600℃ for calcination for 6h, and cool to room temperature, then cut into 3-5mm strip-shaped materials to obtain a copper-based ester hydrogenation catalyst CAT-02.

[0088] Application Example 2

[0089] 1) Fresh water / condensed water recovered from the dehydration tower is pumped at a flow rate of 12 kg / h to backwash the fresh / circulating hydrogenation catalyst from the filter to the hydrogenation mixing kettle, the hydrogenation catalyst is a platinum / coconut shell carbon catalyst solution with a mass concentration of 2%, the content of platinum in the platinum / coconut shell carbon catalyst is 5wt%, and the PTA is transported to the hydrogenation mixing kettle by a screw conveyor (the conveying speed is 4 kg / h), after being mixed uniformly and preheated, the material is pumped into the three-kettle series hydrogenation reaction kettle by a high-pressure pump, under the conditions of 180℃ and 6 MPa hydrogen, the CHDA aqueous solution is prepared by catalytic hydrogenation and filter filtration, and the total average residence time of the reaction material in the three series hydrogenation reaction kettles is 5h;

[0090] 2) The CHDA aqueous solution from step 1) is mixed with the bottom liquid from the DMCD rectification tower, and then is dehydrated in the dehydration tower (the mass of the bottom liquid is 30% of the mass of the CHDA entering the dehydration tower), after dehydration, the CHDA mixture is pumped into the esterification reactor by a pump, and is esterified with methanol from the tank area (the flow rate is 6 kg / h) under the conditions of 190℃ and 3.3 MPa (the total average residence time of the esterification material in the esterification reactor is 3h), after esterification, the material is subjected to demethanolization tower to remove methanol and water, the light components are removed to the demethanolization tower to recover methanol, and the bottom material is subjected to the DMCD rectification tower for rectification and purification to obtain DMCD with a purity of more than 99%, and the bottom liquid is mixed with the CHDA aqueous solution from the PTA hydrogenation section and is subjected to the dehydration tower;

[0091] 3) Take 50 kg CAT-02 into a fixed bed reactor, DMCD from step 2) is vaporized, superheated, and then subjected to ester hydrogenation reaction in a hydrogenation reactor at 230℃, 4.5 MPa, and in the presence of CAT-02 catalyst. The reactor material is subjected to condensation, gas-liquid separation, and rectification purification to produce high anti-CHDM. The reaction performance is shown in Table 1.

[0092] Example 3

[0093] 1) Take 241.6 kg of copper nitrate trihydrate, 178.0 kg of 50 wt% aqueous manganese nitrate solution, and 120.0 kg of zinc nitrate hexahydrate, dissolve in 10 kg of water to prepare a mixed salt aqueous solution for later use; take 152.0 kg of sodium hydroxide, dissolve in 1500 kg of water to prepare an alkali solution for later use;

[0094] 2) Transfer the alkali solution prepared in step 1) to a reaction kettle, stir and heat to 40℃, and then uniformly drop the mixed salt aqueous solution prepared in step 1) into the reaction kettle within 3h, and keep the temperature for 3h before filtering, and then wash with water for 3 times, each time using 1000 kg of water;

[0095] 3) Take 10.0 kg of polyethylene glycol microspheres, mix with the filter cake obtained in step 2) uniformly, and then extrude into strips using an extruder at 70℃ for 6h, to obtain strip-shaped materials, and the extruder aperture is 4mm;

[0096] 4) Dry the strip-shaped materials obtained in step 3) at 110℃ for 4h, then heat to 250℃ for 4h, keep the temperature for 4h, then heat to 650℃ for calcination for 6h, and then cool to room temperature, cut into 3-5mm strip-shaped materials to obtain a copper-based ester hydrogenation catalyst CAT-03.

[0097] Application Example 3

[0098] 1) Fresh water / condensed water recovered from the dehydration system is pumped at a flow rate of 12 kg / h to backwash the fresh / circulating hydrogenation catalyst from the filter to the hydrogenation mixing kettle. The hydrogenation catalyst is a 2% palladium powder carbon catalyst solution, and the content of palladium in the palladium powder carbon catalyst is 5 wt%. The PTA is fed into the hydrogenation mixing kettle by a screw conveyor (the feeding speed is 6 kg / h), and then mixed and preheated. The material is then pumped into a three-kettle series hydrogenation reactor by a high-pressure pump under the conditions of 180℃ and 5 MPa hydrogen. After catalytic hydrogenation and filtration by a filter, a CHDA aqueous solution is obtained. The total average residence time of the reaction material in the three series hydrogenation reactors is 6h;

[0099] 2) The CHDA aqueous solution from step 1) is mixed with the DMCD rectification column bottom liquid and then dehydrated in the dehydration column (the bottom liquid mass is 30% of the CHDA mass entering the dehydration column), and the CHDA mixture after dehydration is pumped into the esterification reactor by a pump, mixed with the methanol from the tank area (flow rate is 9 kg / h), and esterified under the conditions of 190°C and 3.3 MPa (the total average residence time of the esterification material in the esterification reactor is 3 h), and the material after esterification is removed of methanol and water by a demethanizer, the light components are removed of methanol in the demethanizer to recover methanol, and the bottom material is sent to the DMCD rectification column for purification to obtain DMCD with a purity of more than 99%, and the bottom liquid is mixed with the CHDA aqueous solution from the PTA hydrogenation section and sent to the dehydration column;

[0100] 3) 100 kg of CAT-03 is weighed and loaded into a fixed bed reactor, the DMCD from step 2) is sent to a vaporizer and a superheater and then to the hydrogenation reactor to undergo ester hydrogenation reaction under the conditions of 230°C, 3.0 MPa, and the action of CAT-03 catalyst, and the reactor material is condensed, gas-liquid separated, and purified by rectification to prepare high-trans CHDM, and the reaction performance is shown in Table 1.

[0101] Example 4

[0102] 1) 250.0 kg of copper sulfate pentahydrate, 60.0 kg of magnesium sulfate, and 144.0 kg of zinc sulfate heptahydrate are weighed and dissolved in 10 kg of water to prepare a mixed salt aqueous solution for later use; 160.0 kg of sodium hydroxide is weighed and dissolved in 1500 kg of water to prepare an alkali solution for later use;

[0103] 2) The alkali solution prepared in step 1) is transferred to a reaction kettle, stirred and heated to 80°C, and the mixed salt aqueous solution prepared in step 1) is uniformly added dropwise into the reaction kettle within 3 h, and after being kept at temperature for 6 h, it is filtered and washed with water three times, each time using 1000 kg of water;

[0104] 3) 10.0 kg of 27.5 wt% hydrogen peroxide solution is weighed and uniformly mixed with the filter cake obtained in step 2), and after being kept at 50°C for 12 h, it is formed into a strip shape by a strip extruder with a pore size of 4 mm.

[0105] 4) The strip-shaped material obtained in step 3) is dried at 60°C for 6 h, heated to 200°C for 4 h, kept at temperature for 6 h, heated to 600°C for 4 h, and then cooled to room temperature, and cut into a strip shape with a length of 3-5 mm to obtain a copper-based ester hydrogenation catalyst CAT-04.

[0106] Application Example 4

[0107] 1) fresh water / condensed water from the dehydration column recovery loop is pumped at a flow rate of 12 kg / h to backwash fresh / circulating hydrogenation catalyst from the filter to the hydrogenation mixing kettle, the hydrogenation catalyst is a solution of platinum / cocoanut shell charcoal catalyst with a mass concentration of 2%, the platinum / cocoanut shell charcoal catalyst has a platinum content of 5 wt%, PTA is conveyed to the hydrogenation mixing kettle by a screw conveyor (the conveying speed is 8 kg / h), after being mixed uniformly and preheated, the material is pumped into the three-kettle series hydrogenation reactor by a high-pressure pump, under the conditions of 170°C and 6 MPa hydrogen, the material is subjected to catalytic hydrogenation and filtration by a filter to prepare a CHDA aqueous solution, the total average residence time of the reaction material in the three series hydrogenation reactors is 5 h;

[0108] 2) the CHDA aqueous solution from step 1) is mixed with the column bottom liquid from the DMCD rectification column and then is dehydrated in a dehydration column (the column bottom liquid has a mass of 10% of the mass of the CHDA entering the dehydration column), after dehydration, the CHDA mixture is pumped into an esterification reactor by a pump and is esterified with methanol (the flow rate is 12 kg / h) from the tank area under the conditions of 190°C and 3.3 MPa (the total average residence time of the esterification material in the esterification reactor is 3 h), after esterification, the material is subjected to methanol and water removal by a demethanolization column, the light components are removed to the methanol column to recover methanol, and the column bottom material is subjected to rectification and purification in the DMCD rectification column to obtain DMCD with a purity of more than 99%, and the column bottom liquid is mixed with the CHDA aqueous solution from the PTA hydrogenation section and is subjected to dehydration in the dehydration column;

[0109] 3) 80 kg of CAT-04 is weighed and is loaded into a fixed-bed reactor, the DMCD from step 2) is subjected to vaporization and superheating by a vaporizer and a superheater and then is subjected to ester hydrogenation reaction in the hydrogenation reactor under the conditions of 220°C, 2.0 MPa, and the action of the CAT-04 catalyst, after condensation, gas-liquid separation, and rectification and purification, high-trans CHDM is prepared, and the reaction performance is shown in Table 1.

[0110] As shown in Table 1, the copper-based catalyst with a high pore diameter and a high specific surface area is prepared by the method of mixing the pore expander with the alkali for pore expansion, and the catalyst is particularly suitable for preparing CHDM by hydrogenating 1,4-cyclohexane dimethyl ester, and CHDM with a trans ratio of more than 75% can be obtained at a relatively low temperature.

[0111] Table 1 Conditions and results of application examples 1-4

[0112]

[0113] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form. It should be noted that, for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. The application of a copper-based ester hydrogenation catalyst in the preparation of 1,4-cyclohexanedimethyl ester from 1,4-cyclohexanedimethyl ester, wherein the preparation method of the copper-based ester hydrogenation catalyst includes the following steps: A soluble copper salt, a soluble salt of a metal additive, an alkaline substance, and water are mixed and subjected to a precipitation reaction to obtain a hydroxide precipitate. The hydroxide precipitate was mixed with a pore-expanding agent and then cured to obtain a mixture. The mixture was sequentially washed with water, dried and calcined to obtain the copper-based ester hydrogenation catalyst. The metal element in the soluble salt of the metal additive includes one or more of manganese, zinc, aluminum, magnesium, nickel, tin, chromium and iron. The molar ratio of the metal element in the soluble salt of the metal additive to the copper element in the soluble copper salt is 0 to 2:1, and the molar amount of the metal element is not 0. The roasting process is a programmed temperature increase, which is as follows: the temperature is increased from room temperature to 60-120°C within 1 hour, and held for 4-6 hours; then the temperature is increased to 220-320°C within 4-8 hours, and held for 4-6 hours; finally, the temperature is increased to 500-650°C within 4-8 hours, and held for 4-6 hours.

2. The application according to claim 1, characterized in that, The pore-expanding agent includes one or more of polymethyl methacrylate microspheres, polyethylene glycol microspheres, polyvinyl alcohol microspheres, naphthalene, ammonium bicarbonate, and hydrogen peroxide.

3. A method for preparing 1,4-cyclohexanediethanol, characterized in that, Includes the following steps: A hydrogenation reaction was carried out by mixing terephthalic acid and a hydrogenation catalyst to obtain 1,4-cyclohexanedicarboxylic acid; The 1,4-cyclohexanedicarboxylic acid was mixed with methanol and subjected to an esterification reaction to obtain 1,4-cyclohexanedimethyl ester; The 1,4-cyclohexanedimethyl ester is mixed with an ester hydrogenation catalyst to carry out an ester hydrogenation reaction, thereby obtaining the 1,4-cyclohexanediethanol. The preparation method of the ester hydrogenation catalyst includes the following steps: A soluble copper salt, a soluble salt of a metal additive, an alkaline substance, and water are mixed and subjected to a precipitation reaction to obtain a hydroxide precipitate. The hydroxide precipitate was mixed with a pore-expanding agent and then cured to obtain a mixture. The mixture was sequentially washed with water, dried and calcined to obtain a copper-based ester hydrogenation catalyst. The metal element in the soluble salt of the metal additive includes one or more of manganese, zinc, aluminum, magnesium, nickel, tin, chromium and iron. The molar ratio of the metal element in the soluble salt of the metal additive to the copper element in the soluble copper salt is 0 to 2:1, and the molar amount of the metal element is not 0. The roasting process is a programmed temperature increase, which is as follows: the temperature is increased from room temperature to 60-120°C within 1 hour, and held for 4-6 hours; then the temperature is increased to 220-320°C within 4-8 hours, and held for 4-6 hours; finally, the temperature is increased to 500-650°C within 4-8 hours, and held for 4-6 hours.

4. The preparation method according to claim 3, characterized in that, The ester hydrogenation reaction is carried out at a temperature of 180–240 °C, a reaction pressure of 2–6 MPa, a hydrogen-ester molar ratio of 100–300:1, and a feed space velocity of 0.05–0.5 h⁻¹. -1 .

5. The preparation method according to claim 3, characterized in that, The esterification reaction further includes the following steps: the obtained esterification product is distilled through a methanol removal column to obtain a light component and bottom product, the light component is recycled for the esterification reaction, and the bottom product is purified by distillation through a 1,4-cyclohexane dimethyl ester distillation column to obtain the 1,4-cyclohexane dimethyl ester and bottom liquid, the bottom liquid is recycled for the esterification reaction.

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