1, 4-cyclohexanedimethanol and preparation method thereof

Abstract

The invention relates to the technical field of catalytic hydrogenation, and particularly provides 1, 4-cyclohexanedimethanol and a preparation method thereof. The preparation method of 1, 4-cyclohexanedimethanol comprises the following steps: mixing dimethyl 1, 4-cyclohexanedicarboxylate and organic alcohol to obtain a mixed solution, carrying out a catalytic hydrogenation reaction on the mixed solution in an inert atmosphere under the action of an activated supported copper-based catalyst, so that the organic alcohol contained in the mixed solution is converted into a hydrogen donor, and carrying out a hydrogenation reaction on the hydrogen donor to obtain 1, 4-cyclohexanedimethanol. 1, 4-cyclohexane dicarboxylic acid dimethyl ester contained in the mixed solution is converted into 1, 4-cyclohexane dimethanol under the action of a hydrogen donor. The 1, 4 cyclohexanedimethanol is prepared by using the preparation method. According to the 1, 4-cyclohexanedimethanol and the preparation method provided by the invention, the catalytic hydrogenation reaction under the condition of no exogenous hydrogen is realized, the usage amount of hydrogen is reduced, the energy consumption is reduced, and the reaction safety is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of catalytic hydrogenation, and particularly to a 1,4-cyclohexanedimethanol and a preparation method thereof. Background Art

[0002] 1,4-Cyclohexanedimethanol (CHDM) is a diol with extremely high application value and is an important monomer for producing high-value-added polyesters industrially. CHDM not only has the properties of a diol but also has a high degree of symmetry. The polyester materials synthesized with CHDM as the monomer have many excellent properties, such as thermal stability, chemical stability, and good electrical properties, etc. Currently, CHDM has been widely used in the production of chemical products such as polyester fibers, polyester resins, coatings, and lubricants.

[0003] Currently, 1,4-cyclohexanedimethanol is generally prepared by gas-phase hydrogenation or liquid-phase hydrogenation of 1,4-cyclohexanedicarboxylate dimethyl ester (DMCD). However, both gas-phase hydrogenation and liquid-phase hydrogenation require a large amount of hydrogen to be added to the reaction system, which increases energy consumption, and the flammability and explosiveness of hydrogen increase the safety risk of the reaction. The source, transportation, and storage of hydrogen are also inconvenient. Summary of the Invention

[0004] In view of the above problems, the present disclosure is proposed. The present disclosure provides a 1,4-cyclohexanedimethanol and a preparation method thereof.

[0005] According to one aspect of the present disclosure, a preparation method of 1,4-cyclohexanedimethanol is provided, including:

[0006] Mixing 1,4-cyclohexanedicarboxylate dimethyl ester and an organic alcohol to obtain a mixed solution;

[0007] Under the condition of an inert atmosphere, under the action of an activated supported copper-based catalyst, performing a catalytic hydrogenation reaction on the mixed solution, so that the organic alcohol contained in the mixed solution is converted into a hydrogen donor, and the 1,4-cyclohexanedicarboxylate dimethyl ester contained in the mixed solution is converted into 1,4-cyclohexanedimethanol under the action of the hydrogen donor.

[0008] Compared with the prior art, the preparation method of 1,4-cyclohexanedimethanol provided by the present invention has the following advantages:

[0009] In the method for preparing 1,4 - cyclohexanedimethanol provided by the embodiments of the present invention, first, dimethyl 1,4 - cyclohexanedicarboxylate and an organic alcohol are mixed to obtain a mixed solution. Therefore, the organic alcohol can serve as a solvent for dimethyl 1,4 - cyclohexanedicarboxylate, enabling dimethyl 1,4 - cyclohexanedicarboxylate to be uniformly dispersed in the solvent to form a homogeneous system. Secondly, under an inert atmosphere condition, a catalytic hydrogenation reaction is carried out on the mixed solution under the action of an activated supported copper - based catalyst. Since the organic alcohol molecule contains a hydroxyl group and the O - H bond energy of alcohols is relatively weak, in the catalytic hydrogenation reaction system, under the action of the supported copper - based catalyst, the O - H bond of the organic alcohol is more likely to be activated and broken to undergo a dehydrogenation reaction, generating hydrogen atoms. The hydrogen atoms are distributed in the reaction environment as hydrogen donors for the catalytic reaction. During the reaction process, the carbonyl group in the dimethyl 1,4 - cyclohexanedicarboxylate molecule will gradually combine with the hydrogen atoms to reduce the carbonyl group to a hydroxyl group, thereby realizing the conversion of dimethyl 1,4 - cyclohexanedicarboxylate into 1,4 - cyclohexanedimethanol. It can be seen that compared with the traditional hydrogenation reaction using pure hydrogen as the hydrogen source, the amount of hydrogen used is reduced, and the reaction safety is improved to a certain extent. At the same time, this reaction system can reduce the dependence on high - purity hydrogen, and the alcohol as a solvent can be recycled, which conforms to the concept of green chemistry, reducing the generation of waste and energy consumption in the chemical process. Therefore, on the one hand, the organic alcohol in the reaction system can ensure the uniformity of the reaction by dissolving dimethyl 1,4 - cyclohexanedicarboxylate, and on the other hand, it can continuously provide hydrogen atoms to ensure the smooth progress of the hydrogenation reaction.

[0010] In addition, according to another aspect of the present disclosure, there is provided a 1,4 - cyclohexanedimethanol prepared by using the method for preparing 1,4 - cyclohexanedimethanol of the present disclosure.

[0011] It should be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the claimed technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] By describing the embodiments of the present disclosure in more detail in conjunction with the accompanying drawings, the above - mentioned and other objects, features, and advantages of the present disclosure will become more apparent. The drawings are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation to the present disclosure. In the drawings, the same reference numerals generally represent the same components or steps.

[0013] Figure 1 is a flowchart for preparing 1,4 - cyclohexanedimethanol according to the embodiments of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] To make the objectives, technical solutions, and advantages of the present disclosure more apparent, exemplary embodiments according to the present disclosure will be described in detail below with reference to the accompanying drawings. Apparently, the described embodiments are only a part rather than all of the embodiments of the present disclosure. It should be understood that the present disclosure is not limited by the exemplary embodiments described herein.

[0015] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present disclosure, "a plurality of" means two or more unless otherwise specifically defined. "Several" means one or more unless otherwise specifically defined.

[0016] In the description of the present disclosure, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present disclosure.

[0017] It should be noted that in the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present disclosure should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific manner.

[0018] In the present invention, "at least one" means one or more, and "a plurality of" means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, or B exists alone, where A and B may be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b, or c may represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b, and c, where a, b, and c may be single or multiple.

[0019] Currently, the industrial preparation method of CHDM is to obtain CHDM through a two-step hydrogenation process using dimethyl terephthalate (DMT) as the raw material. For example: First, DMT undergoes the first-step benzene ring hydrogenation reaction under the action of a catalyst to produce dimethyl 1,4-cyclohexanedicarboxylate, and then dimethyl 1,4-cyclohexanedicarboxylate undergoes the second-step ester hydrogenation reaction under the action of a catalyst to generate 1,4-cyclohexanedimethanol. Industrially, the process of hydrogenating DMCD to prepare CHDM generally uses gas-phase hydrogenation or liquid-phase hydrogenation.

[0020] Due to the low saturated vapor pressures of DMCD and CHDM, for gas-phase reactions, a huge amount of hydrogen recycling is required. Generally, the hydrogen-oil molar ratio needs to be above 600. A large amount of hydrogen has certain advantages in terms of production capacity and energy consumption. For liquid-phase reactions, liquid-phase hydrogenation is a gas-solid-liquid three-phase reaction, and the hydrogen concentration on the catalyst surface is low. Therefore, in order to improve the reaction efficiency, it is still necessary to externally add a large amount of hydrogen to increase the pressure in the reaction system to improve the solubility of hydrogen in the liquid phase, so as to realize the hydrogenation of DMCD in the liquid phase. It can be seen that whether gas-phase hydrogenation or liquid-phase hydrogenation is used, a large amount of hydrogen needs to be added to the reaction system, which has high requirements for equipment, thus increasing energy consumption, and the flammability and explosiveness of hydrogen increase the safety risk of the reaction. The source, transportation, and storage of hydrogen are also inconvenient.

[0021] In view of the above problems, the embodiments of the present disclosure provide a method for preparing 1,4-cyclohexanedimethanol. Using organic alcohols as both hydrogen donors and solvents simultaneously, catalytic hydrogenation reactions are realized under the condition of no external hydrogen, reducing the usage amount of hydrogen, lowering energy consumption, and improving the safety of the reaction.

[0022] The method for preparing 1,4-cyclohexanedimethanol provided by the embodiments of the present disclosure can be used to prepare 1,4-cyclohexanedimethanol of the embodiments of the present invention. Figure 1 The flowchart of the method for preparing 1,4-cyclohexanedimethanol of the embodiments of the present disclosure is shown. As Figure 1 shown, the method for preparing 1,4-cyclohexanedimethanol of the embodiments of the present disclosure includes:

[0023] Step 101: Mix dimethyl 1,4-cyclohexanedicarboxylate and an organic alcohol to obtain a mixed solution. It should be understood that the organic alcohol may include at least one of methanol, ethanol, isopropanol, and n-butanol. For example: the organic alcohol can be any one of methanol, ethanol, isopropanol, and n-butanol, or a mixture of methanol and ethanol, a mixture of methanol and isopropanol, a mixture of methanol and n-butanol, a mixture of ethanol and isopropanol, etc., or a mixture of methanol, ethanol, and isopropanol, a mixture of ethanol, isopropanol, and n-butanol, etc. No limitation is made here.

[0024] In practical applications, dimethyl 1,4-cyclohexanedicarboxylate can be mixed with any single organic alcohol or a combination of organic alcohols to obtain a mixed solution. Therefore, the organic alcohol can serve as a solvent for dimethyl 1,4-cyclohexanedicarboxylate, enabling dimethyl 1,4-cyclohexanedicarboxylate to be uniformly dispersed in the solvent, forming a homogeneous system. During the subsequent catalytic reaction process, the DMCD molecules can fully contact the active sites on the surface of the catalyst, increasing the probability of effective collisions between the reactants, thereby accelerating the reaction rate and improving the hydrogenation conversion efficiency of DMCD.

[0025] In one feasible embodiment, in the above-mentioned mixed solution, the mass ratio of dimethyl 1,4-cyclohexanedicarboxylate to the organic alcohol is (1-5):100. Within this mass ratio range, it can ensure that the organic alcohol continuously provides hydrogen atoms for the reaction, ensuring that the hydrogenation reaction proceeds continuously and relatively smoothly, and avoiding situations such as too slow reaction rate or difficult effective initiation of the reaction due to too much or too little hydrogen donor, which helps to improve the efficiency of the entire reaction to produce 1,4-cyclohexanedimethanol.

[0026] Step 102: Under an inert atmosphere condition, under the action of the activated supported copper-based catalyst, perform a catalytic hydrogenation reaction on the mixed solution, so that the organic alcohol contained in the mixed solution is converted into a hydrogen donor, and the dimethyl 1,4-cyclohexanedicarboxylate contained in the mixed solution is converted into 1,4-cyclohexanedimethanol under the action of the hydrogen donor.

[0027] In practical applications, under an inert atmosphere condition, when performing a catalytic hydrogenation reaction on the mixed solution under the action of the activated supported copper-based catalyst, since the organic alcohol molecule contains a hydroxyl group and the O-H bond energy of alcohols is relatively weak, therefore, in the catalytic hydrogenation reaction system, under the action of the supported copper-based catalyst, the O-H bond of the organic alcohol is more easily activated and broken to undergo a dehydrogenation reaction, generating hydrogen atoms, and the hydrogen atoms are distributed in the reaction environment as the hydrogen donor for the catalytic reaction. During the reaction process, the carbonyl group in the dimethyl 1,4-cyclohexanedicarboxylate molecule will gradually combine with the hydrogen atoms, reducing the carbonyl group to a hydroxyl group, thereby achieving the conversion of dimethyl 1,4-cyclohexanedicarboxylate into 1,4-cyclohexanedimethanol.

[0028] It can be seen that compared with the traditional hydrogenation reaction using pure hydrogen as the hydrogen source, the amount of hydrogen used is reduced, and the reaction safety is improved to a certain extent. At the same time, this reaction system can reduce the dependence on high-purity hydrogen, and the alcohol can be recycled as a solvent, which conforms to the concept of green chemistry, reducing the generation of waste and energy consumption in the chemical process. Therefore, on the one hand, the organic alcohol in the reaction system can ensure the homogeneity of the reaction by dissolving dimethyl 1,4-cyclohexanedicarboxylate, and on the other hand, it can continuously provide hydrogen atoms to ensure the smooth progress of the hydrogenation reaction.

[0029] For the above-mentioned activated supported copper-based catalyst, it may include an active component, a promoter, and a carrier. The active component includes at least one of Cu and CuO, and the promoter includes ZnO, ZrO 2 , CaO, MnO, Cr 2 O 3 and at least one of them. The carrier includes Al 2 O 3 . Among them, the active component, as the key active center of the hydrogenation reaction, can effectively adsorb and activate hydrogen molecules, and promote the hydrogenation reaction of hydrogen atoms with the unsaturated bonds in the dimethyl 1,4-cyclohexanedicarboxylate molecule. The promoters ZnO, ZrO 2 , CaO, MnO, Cr 2 O 3 and others interact with the active component, further enhancing the activity of the catalyst. The carrier Al 2 O 3 has a high specific surface area, which can highly disperse the active component and the promoter on the surface of Al 2 O 3 . The highly dispersed state enables more Cu atoms to be exposed, increasing the number of active sites, allowing for sufficient contact with the reactants, and thus improving the overall catalytic activity of the catalyst. At the same time, the chemical interaction between Al 2 O 3 and the active component and the promoter also helps to adjust the electronic structure of the active component, enhance its adsorption ability for the reactants, and promote the reaction.

[0030] Exemplarily, in the above-mentioned activated supported copper-based catalyst, the mass ratio of the active component, the promoter, and the carrier is (10 - 60):(5 - 30):(10 - 60). A suitable carrier mass ratio can ensure that the active component and the promoter are stably attached to its surface, maintain the structural integrity of the catalyst, make the performance of the catalyst stable during the long-term reaction process, thereby reducing production costs and improving production efficiency.

[0031] In one example, the reaction conditions for the above catalytic hydrogenation reaction include: the pressure of the catalytic hydrogenation reaction is 5 MPa to 8 MPa, the temperature of the catalytic hydrogenation reaction is 180 °C to 250 °C, and the time of the catalytic hydrogenation reaction is 4 h to 10 h. Preferably, the pressure of the catalytic hydrogenation reaction is 6 MPa to 7 MPa, and the temperature of the catalytic hydrogenation reaction is 235 °C to 245 °C. Within this temperature range of the catalytic hydrogenation reaction, sufficient kinetic energy is imparted to the reactant molecules, enabling them to overcome the activation energy barrier of the reaction. This not only ensures the efficient activation of organic alcohols and the catalytic conversion ability of reactants but also effectively inhibits the occurrence of side reactions. Within this pressure range of the catalytic hydrogenation reaction, the adsorption amount of hydrogen atoms on the catalyst surface increases significantly. More hydrogen atoms can be closely arranged around the active sites of the catalyst, ready to participate in the reaction at any time, making the raw material supply for the hydrogenation reaction more sufficient. At the same time, dimethyl 1,4-cyclohexanedicarboxylate can also be more efficiently adsorbed on the catalyst, in full contact with hydrogen, greatly increasing the initial reaction rate and accelerating the conversion process to the target product.

[0032] In an achievable manner, before the catalytic hydrogenation reaction of the mixed solution under the action of the activated supported copper-based catalyst under inert atmosphere conditions in the embodiments of the present disclosure, the preparation method further includes: First, feed the supported copper-based catalyst into the reaction vessel and perform an activation treatment under the condition of a hydrogen-containing atmosphere to obtain the activated supported copper-based catalyst. Then, feed the mixed solution into the reaction vessel.

[0033] Exemplarily, the same reaction vessel can be used to first perform an activation treatment on the supported copper-based catalyst. After the activation treatment is completed, a mixed solution of dimethyl 1,4-cyclohexanedicarboxylate and organic alcohol is added to the reaction vessel for catalytic hydrogenation reaction. Using the same reaction vessel for multiple steps of operation eliminates the need to transfer the catalyst and reactants between different reaction vessels, avoiding complex material transfer processes and problems such as material loss, contamination, and catalyst activity decline that may result therefrom. The subsequent reaction is directly carried out after the activation process is completed, making the various stages of the reaction closely connected. This continuity helps to maintain the thermal stability of the reaction system and reduce reaction delays caused by factors such as temperature changes. Moreover, operating within the same container reduces the interference of external factors on the reaction, thus facilitating the improvement of product purity.

[0034] Under the above hydrogen-containing atmosphere, the supported copper-based catalyst is activated. Hydrogen can reduce copper to metallic copper atoms. After the mixed solution is fed into the reaction vessel, the metallic copper atoms can serve as the active centers for the catalytic hydrogenation reaction, adsorbing and activating dimethyl 1,4-cyclohexanedicarboxylate and organic alcohol molecules, providing reactive sites for the subsequent reaction. Moreover, the activation process can also adjust the microstructure of the supported copper-based catalyst, enabling better dispersion of copper atoms on the surface of the support. Appropriate dispersion can increase the number of active sites and prevent the aggregation of copper atoms during the reaction, thus ensuring that the catalyst has good activity and stability, significantly improving the reaction rate, and shortening the time required for the reaction to reach equilibrium.

[0035] It can be understood that the above reaction vessel can include a fixed-bed reactor. Since there is a solid catalyst bed inside the fixed-bed reactor, during the catalytic reaction, the activated supported copper-based catalyst will be filled in the fixed-bed reactor to form a fixed catalyst bed. Due to the fixed position of the catalyst bed, the contact between catalyst particles is close, and there will be no situation where some catalysts cannot effectively participate in the reaction due to the violent movement of catalyst particles, thus improving the utilization rate of the supported copper-based catalyst. At the same time, the catalyst is not easily lost, reducing the replacement frequency of the catalyst and lowering the use cost of the catalyst.

[0036] Exemplarily, the feeding method for feeding the above mixed solution into the reaction vessel can be a pumping method. The space velocity of the mixed solution feeding can be 0.25 h -1 ~1.25 h -1 . The feeding space velocity can preferably be 0.25 h -1 ~0.5 h -1 . A stable feeding rate can enable the reactants to fully and effectively contact the active sites of the catalyst. If the feeding rate is too fast, the reactants may pass through the reaction zone before they have time to fully react on the surface of the catalyst, while if the feeding rate is too slow, some active sites of the catalyst will not be utilized. Therefore, setting the feeding space velocity within this range can give full play to the activity of the catalyst, improve its utilization rate, and extend the service life of the catalyst.

[0037] For the conditions of the above hydrogen-containing atmosphere, the hydrogen-containing atmosphere can include an H 2 / N 2 atmosphere with a volume content of 10%.

[0038] In one example, the conditions for the above activation treatment include: the temperature of the activation treatment is 200°C to 300°C, and the time of the activation treatment is 1 h to 8 h. Under these activation conditions, copper or copper oxide can be effectively reduced to metallic copper while maintaining the structural stability of the catalyst support. The metallic copper atoms can be evenly dispersed on the surface of the support, providing a large number of active sites, which is beneficial to the subsequent catalytic hydrogenation reaction of dimethyl 1,4-cyclohexanedicarboxylate.

[0039] In an alternative manner, in the embodiment of the present disclosure, the supported copper-based catalyst is fed into a reaction vessel and subjected to an activation treatment under a hydrogen-containing atmosphere. After obtaining the activated supported copper-based catalyst, before feeding the mixed solution into the reaction vessel, the preparation method further includes: replacing the hydrogen in the reaction vessel with an inert gas so as to form an inert atmosphere in the reaction vessel. It should be understood that the inert atmosphere may include at least one of nitrogen, argon, and helium, and is preferably nitrogen.

[0040] Exemplarily, the same reaction vessel can be used to first perform an activation treatment on the supported copper-based catalyst under a hydrogen-containing atmosphere. After the activation treatment is completed, the hydrogen in the reaction vessel is replaced with an inert gas to form an inert atmosphere in the reaction vessel. Thus, under the inert atmosphere conditions, in the presence of the activated supported copper-based catalyst, a mixed solution of dimethyl 1,4-cyclohexanedicarboxylate and an organic alcohol is added to the reaction vessel for a catalytic hydrogenation reaction to obtain 1,4-cyclohexanedimethanol. By replacing hydrogen with an inert gas after activating the catalyst to form an inert atmosphere in the reaction vessel, side reactions between impurity gases (such as oxygen) and reactants or the catalyst can be effectively avoided. For example, if oxygen is mixed in, it may cause the oxidation of the organic alcohol to generate other impurities, while in such a pure inert atmosphere, the reaction is more likely to proceed along the expected hydrogenation reaction path, resulting in a higher purity of the product 1,4-cyclohexanedimethanol.

[0041] In one example, the preparation method of the above supported copper-based catalyst specifically includes: First, use Cu or CuO, Al 2 O 3 and ZnO, ZrO 2 , CaO, MnO, Cr 2 O 3At least one metal salt in it is used to prepare a metal salt mixed solution. Secondly, the prepared alkaline solution is used as a precipitant. Then, a four-necked flask filled with deionized water is placed in a constant temperature water bath. A pH meter, an electric stirrer paddle, and two constant flow pipettes are inserted into the four-necked flask. The above-prepared precipitant and metal salt mixed solution are simultaneously dropped into the flask through the two constant flow pipettes. During this period, by controlling the dropping rate of the solution, the pH value of the solution is detected by the pH meter, and the pH value is controlled between 7 and 8. After the dropping is completed, it is stirred, allowed to stand, centrifuged and washed, and after drying, it is heated to 450 °C at a heating rate of 3 °C / min in an air atmosphere, and after calcination for 6 h, a supported copper-based catalyst is obtained.

[0042] The above alkaline solution may include a sodium carbonate solution, and the concentration of the sodium carbonate solution may be 1.5 mol / L.

[0043] In an alternative embodiment, the present disclosure also provides a 1,4-cyclohexanedimethanol, which is prepared by the above-mentioned preparation method of 1,4-cyclohexanedimethanol.

[0044] In order to verify the effect of the 1,4-cyclohexanedimethanol provided by the embodiments of the present invention, the embodiments of the present invention are proved by comparing examples with comparative examples.

[0045] Example 1

[0046] Example 1 of the present invention provides a preparation method of a supported copper-based catalyst, which specifically includes the following steps:

[0047] The first step is to prepare a metal salt mixed solution: Prepare a 1.0 mol / L mixed nitrate solution containing Cu 2+ , Zn 2+ , Zr 4+ , Al 3+ , wherein the mass ratio of each nitrate is prepared according to the composition ratio of the supported copper-based catalyst.

[0048] The second step is to prepare a precipitant: Prepare a 1.5 mol / L Na 2 CO 3 solution as a precipitant.

[0049] Step 3: Preparation of supported copper-based catalyst: Place a four-necked flask containing 100 mL of deionized water in a constant temperature water bath at 60 °C. Insert a pH meter, an electric stirring paddle, and two constant flow burettes into the four-necked flask. Drop the prepared precipitant and metal salt solution into the flask simultaneously. By controlling the dropping rate of the solution, detect the pH value of the solution with a pH meter, and control the pH value between 7 and 8. After the dropping is completed, stir for 6 h, then let it stand for 1 h, and centrifuge and wash. Dry in an oven at 110 °C for 12 h, and then heat it to 450 °C at a heating rate of 3 °C / min in an air atmosphere, and calcine for 6 h to obtain the supported copper-based catalyst.

[0050] Adjust the types of metal salts and the mass ratios of each component in Step 1 to prepare four supported copper-based catalysts with different components and contents, which are named Cat.1, Cat.2, Cat.3, and Cat.4 respectively. The components and contents of the four supported copper-based catalysts are shown in Table 1 below:

[0051] Table 1: Composition of supported copper-based catalyst

[0052]

[0053] Comparative Example 1

[0054] In Comparative Example 1 of the present invention, the catalytic hydrogenation reaction is carried out using the Cat.1 catalyst in Example 1 and a methanol solution of dimethyl 1,4-cyclohexanedicarboxylate, specifically including:

[0055] Step 1: Load 6 mL of the Cat.1 catalyst in Example 1 into a fixed-bed reactor. Under an atmosphere of 10% H 2 / N 2 Heat it to 240 °C at a heating rate of 3 °C and maintain for 4 h to obtain the activated Cat.1 catalyst.

[0056] Step 2: After obtaining the activated Cat.1 catalyst, adjust the reaction temperature in the fixed-bed reactor to 235 °C, then fill the fixed-bed with high-purity H 2 to 7 MPa, maintain the hydrogen flow rate at 20 mL / min, and then pump in a 5 wt% methanol solution of DMCD at a space velocity of 0.5 h -1 and react at a constant temperature for 10 h. The conversion rate of DMCD is 86.0%, and the selectivity of CHDM is 56.7%.

[0057] Example 2

[0058] After the reaction in Comparative Example 1 is completed, use N 2 Replace the H 2 in the fixed-bed reactor 6 times to remove the residual H 2 in the reactor, and then fill the fixed-bed with high-purity N2 To 7 MPa, maintain an inert gas atmosphere, pump in a 5 wt% DMCD methanol solution at a space velocity of 0.5 h-1, and react at a constant temperature for 10 h to obtain the product after DMCD hydrogenation. The conversion rate of DMCD is increased to 96.61%, and the selectivity of CHDM is increased to 60.71%. It can be seen that under the same catalyst and the same reaction conditions, the hydrogen transfer catalyst hydrogenation technology can significantly improve the conversion rate of DMCD and the selectivity of CHDM.

[0059] Example Three

[0060] Load 6 mL of the supported copper-based catalyst in Example 1 into a fixed-bed reactor. Under a 10% H 2 / N 2 atmosphere, heat up to 240 °C at a heating rate of 3 °C and maintain for 4 h to activate the catalyst. After activating the catalyst, adjust the temperature to 235 °C, and then use N 2 to displace 6 times to remove the residual H 2 in the reactor. Subsequently, fill the fixed bed with high-purity N 2 to 7 MPa, and pump in a 5 wt% DMCD methanol solution at a space velocity of 0.5 h -1 and react at a constant temperature for 10 h to obtain the product after DMCD hydrogenation. The conversion rate and selectivity of the catalytic reaction are shown in Table 2 below. The doping of ZrO 2 can significantly improve the activity of the catalyst, followed by CrO 2 .

[0061] Table 2: Catalytic reaction data under different catalysts

[0062] Catalyst Conversion rate of DMCD (%) Selectivity of CHMD (%) Cat.1 96.61 60.71 Cat.2 82.11 50.89 Cat.3 94.23 66.99 Cat.4 80.35 50.75

[0063] Example Four

[0064] Load 6 mL of Cat.1 in Example 1 into a fixed-bed reactor. Under a 10% H 2 / N 2 atmosphere, heat up to 240 °C at a heating rate of 3 °C and maintain for 4 h to activate the Cat.1 catalyst. After activating the Cat.1 catalyst, adjust the temperature to 205 °C - 245 °C, and then use N 2 to displace 6 times to remove the residual H 2 in the reactor. Subsequently, fill the fixed bed with high-purity N 2 to 7 MPa, and pump in a 5 wt% DMCD methanol solution at a space velocity of 0.5 h -1 and react at a constant temperature for 10 h to obtain the product after DMCD hydrogenation. The conversion rate and selectivity of the catalytic reaction are shown in Table 3 below. The preferred reaction temperature for this reaction is 235 °C - 245 °C.

[0065] Table 3: Catalytic reaction data at different reaction temperatures

[0066] Reaction temperature (°C) Conversion rate of DMCD (%) Selectivity of CHMD (%) 205 18.34 13.25 215 23.79 13.54 225 33.93 21.77 235 96.61 60.71 245 96.94 62.46

[0067] Example 5: Charge 6 mL of Cat.1 from Example 1 into a fixed-bed reactor. Under a 10% H 2 / N 2 atmosphere, heat it to 240 °C at a heating rate of 3 °C, maintain for 4 h to activate the Cat.1 catalyst. After activating the Cat.1 catalyst, adjust the temperature to 235 °C, then displace with N 2 for 6 times to remove the residual H 2 in the reactor. Subsequently, charge high-purity N 2 into the fixed bed to different pressures, pump in a 5 wt% DMCD methanol solution at a space velocity of 0.5 h -1 , and react at a constant temperature for 10 h to obtain the product after DMCD hydrogenation. The conversion rate and selectivity of the catalytic reaction are shown in Table 4 below. The preferred reaction pressure for this reaction is 6 MPa to 7 MPa.

[0068] Table 4: Catalytic reaction data at different reaction pressures

[0069] Reaction pressure (MPa) Conversion rate (%) CHMD (%) 3 66.85 36.07 4 79.19 48.61 5 82.21 57.76 6 90.22 62.24 7 96.61 60.71

[0070] Example 6

[0071] Charge 6 mL of Cat.1 from Example 1 into a fixed-bed reactor. Under a 10% H 2 / N 2 atmosphere, heat it to 240 °C at a heating rate of 3 °C, maintain for 4 h to activate the Cat.1 catalyst. After activating the Cat.1 catalyst, adjust the temperature to 235 °C, then displace with N 2 for 6 times to remove the residual H 2 in the reactor. Subsequently, charge high-purity N 2 into the fixed bed to 7 MPa, pump in a 5 wt% DMCD methanol solution at different space velocities, and react at a constant temperature for 10 h to obtain the product after DMCD hydrogenation. The conversion rate and selectivity of the catalytic reaction are shown in Table 5 below. The preferred feed space velocity for this reaction is 0.25 h -1 to 0.5 h -1 .

[0072] Table 5: Catalytic reaction data at different feed space velocities

[0073] <![CDATA[Liquid Hourly Space Velocity LHSV (h -1 )]]> Conversion rate (%) CHMD (%) 0.25 93.16 60.31 0.5 96.61 60.71 0.75 45.21 30.57 1.00 36.4 24.34 1.25 26.14 22.75

[0074] Example 7

[0075] Charge 6 mL of Cat.1 from Example 1 into a fixed-bed reactor. Under a 10% H 2 / N 2 Under an atmosphere, the temperature is raised to 240 °C at a heating rate of 3 °C, maintained for 8 h to activate the Cat.1 catalyst. After the Cat.1 catalyst is activated, the temperature is adjusted to 235 °C, and then N 2 is replaced 6 times to remove the residual H 2 in the reactor. Subsequently, high-purity N 2 is charged into the fixed bed to 7 MPa, and a 5 wt% DMCD organic alcohol solution (mainly including methanol, ethanol, isopropanol, and n-butanol) is pumped in at a space velocity of 0.5 h -1 for 10 h of constant-temperature reaction to obtain the product after DMCD hydrogenation. The conversion rate and selectivity of the catalytic reaction are shown in Table 6 below. Methanol is the optimal choice as a solvent and hydrogen donor.

[0076] Table 6: Catalytic reaction data under different hydrogen donors

[0077] Hydrogen donor Conversion rate (%) CHMD (%) Methanol 96.61 60.71 Ethanol 99.74 28.20 Isopropanol 96.69 5.73 n-Butanol 99.90 23.91

[0078] It can be seen that for 1,4-cyclohexanedimethanol and its preparation method according to the embodiments of the present disclosure, organic alcohols are used as both hydrogen donors and solvents at the same time to achieve catalytic hydrogenation reactions under conditions without exogenous hydrogen, reducing the amount of hydrogen used, lowering energy consumption, and improving the safety of the reaction. Compared with existing methods, it can solve the disadvantage of consuming a large amount of hydrogen in the method of hydrogenation using exogenous hydrogen, and avoid the safety hazards brought by flammable and explosive hydrogen.

[0079] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present disclosure are only examples and not limitations. It cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present disclosure. In addition, the above-mentioned specific details are only for illustrative and easy-to-understand purposes, rather than limitations. The above details do not limit the present disclosure to necessarily adopt the above specific details to implement.

[0080] The block diagrams of the devices, apparatuses, equipment, and systems involved in the present disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any way. Words such as "including", "comprising", "having", etc. are open-ended words, meaning "including but not limited to", and can be used interchangeably with them. The word "or" and "and" used here refer to the word "and / or", and can be used interchangeably with it, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0081] In addition, as used herein, "or" as used in a list of items beginning with "at least one" indicates a disjunctive list such that, for example, a listing of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Further, the phrase "exemplary" does not mean that the examples described are preferred or better than other examples.

[0082] It should also be noted that in the systems and methods of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present disclosure.

[0083] Various changes, substitutions, and alterations to the technologies described herein can be made without departing from the teachings of the technology defined by the appended claims. In addition, the scope of the claims of the present disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and acts described above. Processes, machines, manufactures, compositions of events, means, methods, or acts that currently exist or will later be developed that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Accordingly, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or acts within their scope.

[0084] The foregoing description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0085] The foregoing description has been presented for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those skilled in the art will recognize some of their variations, modifications, alterations, additions, and subcombinations.

Claims

1. A method for preparing 1,4-cyclohexanedimethanol, characterized in that: include: Mixing dimethyl 1,4-cyclohexanedicarboxylate and an organic alcohol to obtain a mixed solution; Under inert atmosphere conditions, the mixed solution is subjected to a catalytic hydrogenation reaction under the action of an activated supported copper-based catalyst, so that the organic alcohol contained in the mixed solution is converted into a hydrogen donor, and the 1,4-cyclohexanedicarboxylic acid dimethyl ester contained in the mixed solution is converted into 1,4-cyclohexanedimethanol under the action of the hydrogen donor.

2. The method for preparing 1,4-cyclohexanedimethanol according to claim 1, characterized in that: The reaction conditions of the catalytic hydrogenation reaction include: the pressure of the catalytic hydrogenation reaction is 5MPa to 8MPa, the temperature of the catalytic hydrogenation reaction is 180°C to 250°C, and the time of the catalytic hydrogenation reaction is 4h to 10h.

3. The method for preparing 1,4-cyclohexanedimethanol according to claim 1, characterized in that: In the mixed solution, the mass ratio of the dimethyl 1,4-cyclohexanedicarboxylate to the organic alcohol is (1-5):

100.

4. The method for preparing 1,4-cyclohexanedimethanol according to claim 1, characterized in that: Before the mixed solution is subjected to a catalytic hydrogenation reaction under the action of an activated supported copper-based catalyst under an inert atmosphere, the method further comprises: Feeding a supported copper-based catalyst into a reaction container, and performing an activation treatment under a hydrogen-containing atmosphere to obtain an activated supported copper-based catalyst; The mixed solution was fed into the reaction vessel at a space velocity of 0.25 h -1 ~1.25h -1 .

5. The method for preparing 1,4-cyclohexanedimethanol according to claim 4, characterized in that: The activation treatment conditions include: the activation treatment temperature is 200° C. to 300° C., and the activation treatment time is 1 hour to 8 hours.

6. The method for preparing 1,4-cyclohexanedimethanol according to claim 4, characterized in that: After feeding the supported copper-based catalyst into a reaction container and performing activation treatment under a hydrogen-containing atmosphere to obtain an activated supported copper-based catalyst, before feeding the mixed solution into the reaction container, the method further comprises: The hydrogen in the reaction container is replaced by an inert gas to form an inert atmosphere in the reaction container.

7. The method for preparing 1,4-cyclohexanedimethanol according to any one of claims 1 to 6, characterized in that: The activated supported copper-based catalyst comprises an active component, an auxiliary agent and a carrier, wherein the active component comprises at least one of Cu and CuO, the auxiliary agent comprises at least one of ZnO, ZrO2, CaO, MnO and Cr2O3, and the carrier comprises Al2O3.

8. The method for preparing 1,4-cyclohexanedimethanol according to claim 7, characterized in that: In the activated supported copper-based catalyst, the mass ratio of the active component, the auxiliary agent and the carrier is (10-60): (5-30): (10-60).

9. The method for preparing 1,4-cyclohexanedimethanol according to any one of claims 1 to 5, characterized in that: The organic alcohol includes at least one of methanol, ethanol, isopropanol and n-butanol.

10. 1,4-cyclohexanedimethanol prepared according to the method for preparing 1,4-cyclohexanedimethanol according to any one of claims 1 to 9.

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