Catalysts for hydrogenation, methods for their preparation and use, and methods for phthalate hydrogenation

Abstract

The present application relates to the technical field of cyclohexane dicarboxylic acid ester preparation, in particular to a catalyst for hydrogenation, a preparation method and application thereof, and a method for hydrogenation of phthalic acid ester. The NH3-TPD main desorption peak position of the catalyst is 170-205 DEG C, the catalyst comprises a carrier and active elements and auxiliary elements supported on the carrier, the active elements are selected from Ru, and the auxiliary elements are selected from one or more of Pd, K, Mg, B, Cs, Zn and Ca. The catalyst provided by the present application is used for hydrogenation of phthalic acid ester to prepare cyclohexane dicarboxylic acid ester, can inhibit the generation of ester exchange or etherification by-products, improve the total selectivity of the target product, and at the same time, retain certain weak acid sites, which is beneficial to realize high dispersion of active metals and improve the conversion rate of raw materials.

Description

Technical Field

[0001] This invention relates to the field of cyclohexane dicarboxylic acid ester preparation technology, specifically to a catalyst for hydrogenation, its preparation method and application, and a method for hydrogenation of phthalic acid esters. Background Technology

[0002] Currently, the world's major producers and patent holders of 1,4-cyclohexanediethanol (CHDM) include Eastman Chemical Company (USA), Mitsubishi Chemical (Japan), and SK Chemicals (South Korea). Eastman Chemical Company is the largest producer, with CHDM production facilities in the United States and Switzerland. In 1959, Eastman Chemical Company first used dimethyl terephthalate (DMT) as a raw material, employing benzene ring hydrogenation and ester hydrogenation processes to produce CHDM, which remains the only industrially applied process. Subsequently, SK NJC, a joint venture between Japan and South Korea, also used this method to achieve large-scale CHDM production. In China, only Kailin Chemical (Zhangjiagang) Co., Ltd. and Jiangsu Kangheng Chemical Co., Ltd. have achieved industrial-scale CHDM production, with an annual output of less than 10,000 tons, making domestic market demand reliant on imports.

[0003] CN103687834A and CN103687834A disclose a method for preparing 1,4-cyclohexanediethanol (CHDM) from terephthalic acid (PTA) via esterification and a two-step hydrogenation process. Terephthalic acid is esterified with methanol to produce dimethyl terephthalate (DMT). The first-stage hydrogenation reaction involves the reaction of DMT with hydrogen in the presence of a Pd-based catalyst to produce dimethyl 1,4-cyclohexanedicarboxylate (DMCD). The second-stage hydrogenation reaction involves the reaction of DMCD with hydrogen in the presence of a Cu-based catalyst to produce CHDM. The methanol generated during this process is recycled back to the esterification reaction. The second-stage hydrogenation is operated under high pressure (10–40 MPa absolute pressure, 180–300 °C, liquid hourly space velocity 0.5–5 h / h). Furthermore, acidic substances such as monoterephthalic acid esters, a byproduct of the first-stage hydrogenation, can affect the activity of the Cu-based catalyst. To address this issue, CN1109859A proposes a gas-phase reaction method for preparing 1,4-cyclohexanediethanol, where a copper-containing catalyst exhibits good tolerance to acidic substances (0.1 wt%–15 wt%) under gas-phase hydrogenation conditions. The gas-phase reaction conditions include a pressure of 3.103–6.895 MPa, a temperature of 200–260 °C, a space velocity of 0.1–1 / h, and a hydrogen-to-ester ratio of 200–1000. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem of low selectivity caused by the formation of heavy components in the hydrogenation of phthalate to cyclohexanedicarboxylate in the prior art, and to provide a catalyst for hydrogenation. This catalyst, when used for the hydrogenation of phthalate to cyclohexanedicarboxylate, can improve the feed conversion rate and increase the overall selectivity of the target product.

[0005] To achieve the above objectives, the present invention provides a catalyst for hydrogenation, wherein the main desorption peak of NH3-TPD is located at 170-205℃. The catalyst comprises a support and an active element and a promoter element supported on the support. The active element is selected from Ru; the promoter element is selected from one or more of Pd, K, Mg, B, Cs, Zn and Ca.

[0006] A second aspect of the present invention provides the application of the catalyst described herein in the hydrogenation of phenyl dicarboxylic acid ester to cyclohexane dicarboxylic acid ester.

[0007] A third aspect of the present invention provides a method for hydrogenating phthalate esters, wherein phthalate esters and hydrogen are reacted with a hydrogenation catalyst; the hydrogenation catalyst contains the catalyst described in the present invention.

[0008] A fourth aspect of the present invention provides a method for preparing the catalyst of the present invention, the method comprising the following steps:

[0009] (1) The carrier powder is treated at a temperature of not less than 400°C, and then the auxiliary elements are loaded onto the carrier to obtain a modified carrier; preferably, the salt solution of the auxiliary elements is brought into contact with the carrier for the first time, and then aged, dried and calcined to obtain a modified carrier.

[0010] (2) The Ru-containing solution, the precipitant solution, the modified support and the aqueous solvent are subjected to a second contact, filtered and dried to obtain the hydrogenation catalyst.

[0011] Compared with the prior art, the catalyst of the present invention lowers the position of the NH3-TPD peak, which can reduce the acidity of the catalyst and retain a certain number of weak acid sites.

[0012] In the prior art, the effect of catalyst acidity on Ru-based catalysts is mainly reflected in (1) strong acid sites of the catalyst cause transesterification or etherification reactions of dimethyl 1,4-cyclohexanedicarboxylate with methyl 4-hydroxymethyl-cyclohexanecarboxylate or dimethyl terephthalate with methyl 4-hydroxymethyl-cyclohexanecarboxylate or their combinations, generating heavy components, resulting in unsatisfactory selectivity during the reaction process; (2) weak acid sites of the catalyst play a certain dispersing role on active metals.

[0013] The catalyst provided by this invention is used for the hydrogenation of diphenylcarboxylic acid esters to prepare cyclohexanedicarboxylic acid esters, especially for the hydrogenation of dimethyl terephthalate to prepare dimethyl 1,4-cyclohexanedicarboxylic acid esters; it can inhibit the formation of transesterification or etherification byproducts and improve the overall selectivity of the target product; at the same time, it retains a certain number of weak acid sites, which is beneficial to achieving high dispersion of active metals and improving the conversion rate of raw materials. Attached Figure Description

[0014] Figure 1 The NH3-TPD diagrams are for the catalysts prepared in Example 1 and Comparative Example 1.

[0015] Figure 2 The images show the XRD patterns of the catalysts prepared in Example 1 and Comparative Example 2. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] The first aspect of this invention provides a catalyst for hydrogenation, wherein the main NH3-TPD desorption peak of the catalyst is located at 170-205°C. The catalyst comprises a support and an active element and a promoter element supported on the support. The active element is selected from Ru; the promoter element is selected from one or more of Pd, K, Mg, B, Cs, Zn, and Ca. The catalyst of this invention lowers the position of the NH3-TPD peak in the catalyst, reduces the acidity of the acidifier, and retains a certain number of weak acid sites.

[0018] According to a preferred embodiment of the present invention, the main desorption peak of the catalyst for NH3-TPD is located at 170-190℃.

[0019] According to a preferred embodiment of the present invention, the auxiliary element is selected from one or more of B, Cs, Mg and Ca.

[0020] According to a preferred embodiment of the present invention, the carrier is selected from at least one of alumina, silicon dioxide and molecular sieve, preferably alumina.

[0021] According to a preferred embodiment of the present invention, the content of active elements is 0.1-35 parts by weight, preferably 0.2-20 parts, and more preferably 0.5-10 parts.

[0022] According to a preferred embodiment of the present invention, the content of the auxiliary element is 1-50 parts by weight, preferably 2-40 parts, and more preferably 4-30 parts.

[0023] According to a preferred embodiment of the present invention, the carrier content is 10-98 parts by weight, preferably 40-96 parts, and more preferably 60-94 parts.

[0024] In this invention, the catalyst content is determined by ICP.

[0025] According to a second aspect of the present invention, the present invention provides the application of the catalyst described herein in the hydrogenation of phenyl dicarboxylate to cyclohexanedicarboxylate, preferably in the hydrogenation of dimethyl terephthalate to dimethyl 1,4-cyclohexanedicarboxylate.

[0026] According to a third aspect of the present invention, a method for hydrogenating phthalic acid esters is provided, wherein phthalic acid esters and hydrogen are reacted with a hydrogenation catalyst; said hydrogenation catalyst contains the catalyst described in this invention. This invention lowers the position of the NH3-TPD peak in the catalyst, reducing the acidity of the acidifying agent. This catalyst, used for the hydrogenation of phthalic acid esters to cyclohexanedicarboxylate, can inhibit the formation of transesterification or etherification byproducts, improving the overall selectivity of the target product. Simultaneously, it retains certain weak acid sites, which is beneficial for achieving high dispersion of active metals and improving the raw material conversion rate.

[0027] According to a preferred embodiment of the present invention, the molar ratio of hydrogen to phthalate is 5:1-200:1, preferably 20:1-80:1; this is beneficial for improving the raw material conversion rate and increasing the total selectivity of cyclohexanedicarboxylate.

[0028] According to a preferred embodiment of the present invention, the contact reaction conditions include: a temperature of 100-250°C, preferably 140-220°C; a pressure of 4.0-15.0 MPa, preferably 7.0-13.0 MPa; and a liquid hourly space velocity of 0.5-12 h⁻¹. -1 Preferably 2-8 hours -1 This is beneficial for improving the conversion rate of raw materials and increasing the overall selectivity of cyclohexanedicarboxylate.

[0029] In this invention, catalysts possessing the aforementioned characteristics can all achieve the objectives of this invention. There is no particular limitation on the preparation method of the catalyst. According to a preferred embodiment of this invention, a method for preparing the aforementioned catalyst is provided, comprising the following steps:

[0030] (1) The carrier powder is treated at a temperature of not less than 400°C, and then the auxiliary elements are loaded onto the carrier to obtain a modified carrier; preferably, the salt solution of the auxiliary elements is brought into contact with the carrier for the first time, and then aged, dried and calcined to obtain a modified carrier.

[0031] (2) The Ru-containing solution, the precipitant solution, the modified support and the aqueous solvent are subjected to a second contact, filtered and dried to obtain the hydrogenation catalyst.

[0032] According to a preferred embodiment of the present invention, in step (1), the carrier is treated at 400-1100°C, preferably 800-1000°C, for 2-8 hours.

[0033] According to a preferred embodiment of the present invention, in step (1), the first contact is either an equal-volume impregnation or an excessive impregnation.

[0034] According to a preferred embodiment of the present invention, in step (1), the aging time is room temperature to 80°C. The aging time is adjusted reasonably according to the temperature. Preferably, the aging time is 1-10h.

[0035] In this invention, there are no particular limitations on the drying conditions in step (1), as long as the solvent can be removed.

[0036] According to a preferred embodiment of the present invention, in step (1), the carrier is calcined in an oxygen-containing gas atmosphere. Preferably, the calcination temperature is 500-1000℃, and the calcination time is adjusted reasonably according to the temperature. Preferably, the calcination time is 2-8h.

[0037] According to a preferred embodiment of the present invention, in step (2), the modified carrier is added to a solution containing Ru salt, and then a precipitant solution is added for a second contact.

[0038] According to a preferred embodiment of the present invention, the pH of the second contact solution at the endpoint is controlled to be 6.0-8.0, more preferably 7.0-8.0.

[0039] According to a preferred embodiment of the present invention, the temperatures of the first contact and the second contact are each 20-90°C; the contact time is reasonably adjusted according to the contact temperature, preferably, the contact time of the first contact and the second contact is each 1-5 hours.

[0040] According to a preferred embodiment of the present invention, the carrier powder has no special requirements. For example, when the carrier is alumina, the carrier powder may be boehmite.

[0041] According to a preferred embodiment of the present invention, the second contact is preferably carried out in the presence of a competing adsorbent, preferably selected from one or more of citric acid, tartaric acid, lauric acid, hydrochloric acid, oxalic acid, lactic acid and trichloroacetic acid; more preferably, the weight ratio of the competing adsorbent to the modified support is 4-35:100.

[0042] In this invention, there is no particular limitation on the salt of the auxiliary element, which can be a salt of a conventional auxiliary element in the art. Preferably, the salt of the auxiliary element is selected from one or more of H2PdCl4, PdCl2, Zn(NO3)2, BBr3, Cs2CO3, KOH, KNO3, Mg(NO3)2 and Ca(NO3)2, and more preferably from one or more of BBr3, Cs2CO3, Mg(NO3)2 and Ca(NO3)2.

[0043] In this invention, there is no particular limitation on the Ru source, which can be any Ru source conventional in the art. Preferably, the Ru source in the Ru-containing solution is at least one of ruthenium chloride, ruthenium chloride acid and ruthenium chloride salt, preferably ruthenium chloride.

[0044] In this invention, there is no particular limitation on the selection of the precipitant, which can be a conventional precipitant in the art. Preferably, the precipitant is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and ammonia water, and more preferably potassium hydroxide and / or ammonia water.

[0045] According to a preferred embodiment of the present invention, the concentration of the salt solution of the auxiliary element is 0.1-3.0 mol / L, preferably 0.3-2.0 mol / L.

[0046] According to a preferred embodiment of the present invention, the concentration of the Ru-containing solution is 0.1-5.0 mol / L, preferably 0.5-4.0 mol / L.

[0047] According to a preferred embodiment of the present invention, the concentration of the precipitant solution is 0.3-3.0 mol / L, preferably 0.5-1.5 mol / L.

[0048] The present invention will be described in detail below through embodiments.

[0049] In the following examples, the dimethyl terephthalate used was industrial grade, dissolved in dimethyl 1,4-cyclohexanedicarboxylate, with a dimethyl terephthalate mass fraction of 4% and a dimethyl 1,4-cyclohexanedicarboxylate mass fraction of 96%; the hydrogen gas used had an integral of 99.9%.

[0050] The acidity of the catalyst was tested using an NH3-TPD instrument. The NH3-TPD desorption peak shifted towards lower temperatures, indicating that the acid strength of the catalyst decreased, making it easier for NH3 to desorb from the catalyst.

[0051] X-ray diffraction (XRD) was used to characterize species dispersion. The smaller the RuO2 diffraction peak, the higher the Ru species dispersion. The larger and sharper the RuO2 diffraction peak, the more likely Ru species are to agglomerate or sinter, indicating low dispersion.

[0052] In the following examples, the content of each component of the catalyst was determined by ICP.

[0053] In this invention, the size of the NH3-TPD peak position represents the different acidity of the catalyst, and is used to compare the acidity between different samples.

[0054] In this invention, the size of the XRD peak represents the dispersion of the species.

[0055] In this invention, the conversion rate and selectivity of dimethyl terephthalate to dimethyl 1,4-cyclohexanedicarboxylate are calculated using the following formulas:

[0056]

[0057]

[0058] In the formula: n – amount of substance, in mol; DMT – dimethyl terephthalate; DMCD – dimethyl 1,4-cyclohexanedicarboxylate; 1 – raw material; 2 – product.

[0059] Example 1

[0060] 1) Catalyst preparation:

[0061] (1) The alumina carrier powder pseudoboehmite was treated at 700℃ for 4 hours;

[0062] (2) Prepare a solution I with a concentration of 0.8 mol / L by mixing the auxiliary salts Cs2CO3 and Mg(NO3)2. Add 12 g of alumina carrier to solution I containing the auxiliary salts by the equal volume impregnation method for the first contact. The temperature of the first contact is 25℃ and the time is 1 h. Stir evenly, age at 25℃ for 3 h, dry at 120℃ for 12 h, and calcine at 600℃ for 4 h to obtain the modified alumina.

[0063] (3) Prepare a ruthenium chloride solution II with a concentration of 0.8 mol / L; prepare a potassium hydroxide precipitant solution III with a concentration of 1.0 mol / L. Add the modified alumina support to solution II, then add solution III for a second contact. The temperature of the second contact is 25℃, and the time is 3 hours. Add alkali to control the pH at the endpoint to 7.5. Aging at 25℃ for 4 hours, filter, wash, and dry to obtain the catalyst. The catalyst contains 2 parts Ru, 1.5 parts Cs, 3 parts Mg, and 93.5 parts support.

[0064] Figure 1 The image shows the NH3-TPD diagram of the catalyst prepared in Example 1, with the main desorption peak at 180.1℃.

[0065] 2) Catalyst reduction:

[0066] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0067] 3) Catalytic hydrogenation:

[0068] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.6%, and the DMCD selectivity was 97.7%.

[0069] Example 2

[0070] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the content of Cs was different; in the catalyst, the content of Ru was 2 parts, the content of Cs was 3 parts, the mass content of Mg was 3 parts, and the content of support was 92 parts.

[0071] 1) Catalyst reduction:

[0072] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0073] 2) Catalytic hydrogenation:

[0074] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.9%, and the DMCD selectivity was 98.1%.

[0075] Example 3

[0076] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the contents of Cs and Mg were different; the contents of Ru in the catalyst were 2 parts, the contents of Cs were 2 parts, the mass content of Mg was 2 parts, and the content of the support was 94 parts.

[0077] 2) Catalyst reduction:

[0078] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0079] 3) Catalytic hydrogenation:

[0080] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.7%, and the DMCD selectivity was 97.6%.

[0081] Example 4

[0082] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, with the difference being: the type and content of the promoters were different; in the catalyst, the content of Ru was 2 parts, the content of Mg was 3 parts, the mass content of Ca was 5 parts, and the content of the support was 90 parts.

[0083] 2) Catalyst reduction:

[0084] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0085] 3) Catalytic hydrogenation:

[0086] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.8%, and the DMCD selectivity was 97.4%.

[0087] Example 5

[0088] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, with the difference being: the type and content of the promoters were different; in the catalyst, the content of Ru was 2 parts, the content of Cs was 1.5 parts, the mass content of Ca was 5 parts, and the content of the support was 91.5 parts.

[0089] 2) Catalyst reduction:

[0090] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0091] 3) Catalytic hydrogenation:

[0092] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.5%, and the DMCD selectivity was 97.3%.

[0093] Example 6

[0094] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the calcination temperature of the modified support was different, and it was calcined at 500°C for 4 hours.

[0095] The main desorption peak of the catalyst for NH3-TPD is located at 192.8℃.

[0096] 2) Catalyst reduction:

[0097] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0098] 3) Catalytic hydrogenation:

[0099] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.5%, and the DMCD selectivity was 95.8%.

[0100] Example 7

[0101] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, with the difference being: the content of components is different; in the catalyst, the content of Ru is 2 parts, the content of Cs is 1.5 parts, the mass content of Mg is 1.5 parts, and the content of support is 95 parts.

[0102] 2) Catalyst reduction:

[0103] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0104] 3) Catalytic hydrogenation:

[0105] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.2%, and the DMCD selectivity was 96.1%.

[0106] Example 8

[0107] The hydrogenation catalyst was prepared using the method described in Example 1, with the difference being that the hydrogenation reaction conditions were different. In step 3), the reaction temperature was 135°C, the reaction pressure was 7.0 MPa, the hydrogen / dimethyl terephthalate molar ratio was 30:1, and the liquid hourly space velocity was 3.0 h⁻¹. -1 The reaction results are shown in Table 1. The DMT conversion rate was 92.8%, and the DMCD selectivity was 95.4%.

[0108] Example 9

[0109] The hydrogenation catalyst was prepared using the method described in Example 1, with the difference being that the hydrogenation reaction conditions were different. In step 3), the reaction temperature was 150°C, the reaction pressure was 6.0 MPa, the hydrogen / dimethyl terephthalate molar ratio was 30:1, and the liquid hourly space velocity was 3.0 h⁻¹. -1 The reaction results are shown in Table 1. The DMT conversion rate was 98.4%, and the DMCD selectivity was 97.1%.

[0110] Example 10

[0111] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, with the difference being: the type of promoter was different; in the catalyst, the content of Ru was 2 parts, the content of K was 1.5 parts, the content of Zn was 3 parts, and the content of support was 93.5 parts.

[0112] 2) Catalyst reduction:

[0113] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0114] 3) Catalytic hydrogenation:

[0115] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 96.2%, and the DMCD selectivity was 95.9%.

[0116] Example 11

[0117] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, the difference being that in step (1): the processing temperature of the support powder was different, which was 1000℃.

[0118] The main desorption peak of the catalyst for NH3-TPD is located at 170.8℃.

[0119] 2) Catalyst reduction:

[0120] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0121] 3) Catalytic hydrogenation:

[0122] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.7%, and the DMCD selectivity was 98.1%.

[0123] Example 12

[0124] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, with the difference being: in step (3), citric acid was added as a competitive adsorbent in the second contact, and the weight ratio of citric acid to the modified support was 30:100. The impregnation solution II was first mixed with the competitive adsorbent, and then the modified alumina support was added to the mixture.

[0125] The main desorption peak of the catalyst for NH3-TPD is located at 174.5℃.

[0126] 2) Catalyst reduction:

[0127] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0128] 3) Catalytic hydrogenation:

[0129] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 99.8%, and the DMCD selectivity was 98.4%.

[0130] Comparative Example 1

[0131] The catalyst in this embodiment was prepared using the same method as the catalyst in Example 1, except that the catalyst does not contain Cs and Mg, and the content of Ru in the catalyst is 2 parts and the content of the support is 98 parts.

[0132] Figure 1 The image shows the NH3-TPD curve of the catalyst prepared in Comparative Example 1, with the main desorption peak at 206.2℃.

[0133] 1) Catalyst reduction:

[0134] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0135] 2) Catalytic hydrogenation:

[0136] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 98.8%, and the DMCD selectivity was 93.6%.

[0137] Comparative Example 2

[0138] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the content of Mg was different; the content of Ru in the catalyst was 2 parts, the content of Cs was 1.5 parts, the mass content of Mg was 30 parts, and the content of support was 66.5 parts.

[0139] 1) Catalyst reduction:

[0140] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0141] 2) Catalytic hydrogenation:

[0142] Using dimethyl terephthalate solution and pure hydrogen as raw materials, with a catalyst dosage of 10 g, the reaction was carried out at a temperature of 150℃, a reaction pressure of 7.0 MPa, a hydrogen / dimethyl terephthalate molar ratio of 30:1, and a liquid hourly space velocity of 3.0 h⁻¹. -1 Hydrogenation experiments were conducted under the specified conditions, and the reaction results are shown in Table 1. The DMT conversion rate was 95.1%, and the DMCD selectivity was 97.5%.

[0143] Table 1

[0144]

[0145]

[0146] Figure 1 The NH3-TPD chromatograms of the catalysts prepared in Example 1 and Comparative Example 1 show that the catalysts synthesized with the addition of basic promoters Cs, Mg, or Ca have suitable acidity, with the main desorption peak of NH3-TPD at 180.1℃, exhibiting high DMT conversion and DMCD selectivity. In contrast, the catalyst in Comparative Example 1, which does not contain Cs and Mg, is more acidic, with the main desorption peak of NH3-TPD at 206.2℃, leading to the formation of more transesterification or etherification byproducts and reducing the overall selectivity of the target product.

[0147] Figure 2 The images show the XRD patterns of the catalysts prepared in Example 1 and Comparative Example 2. In Comparative Example 2, due to the high content of basic promoters in the catalyst, the number of strong acid sites and weak acid sites in the catalyst was greatly reduced. The main desorption peak of NH3-TPD was located at 158.4℃, which in turn caused the RuO2 diffraction peak in the catalyst to become narrower and sharper, indicating that the dispersion of the active component was greatly reduced.

[0148] As can be seen from the results in Table 1, the solution of the present invention has significantly better DMT conversion rate and DMCD selectivity.

[0149] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. The application of a hydrogenation catalyst in the hydrogenation of phenyl dicarboxylic acid esters, characterized in that, The catalyst has a main desorption peak for NH3-TPD at 170-205℃. The catalyst includes a support and an active element and a promoter element supported on the support. The active element is selected from Ru. The promoter element is selected from one or more of Pd, K, Mg, B, Cs, and Zn.

2. The application according to claim 1, wherein, The catalyst has a main NH3-TPD desorption peak at 170-190℃; and / or The auxiliary element is selected from one or both of Cs and Mg; and / or The carrier is selected from at least one of alumina, silica, and molecular sieve.

3. The application according to claim 2, wherein, The carrier is selected from alumina.

4. The application according to claim 1, wherein, By weight, The content of active elements is 0.1-35 parts; and / or The content of auxiliary elements is 1-50 parts; and / or The carrier content is 10-98 parts.

5. The application according to claim 4, wherein, By weight, The content of active elements is 0.2-20 parts; and / or The content of auxiliary elements is 2-40 parts; and / or The carrier content is 40-96 parts.

6. The application according to claim 5, wherein, By weight, The content of active elements is 0.5-10 parts; and / or The content of auxiliary elements is 4-30 parts; and / or The carrier content is 60-94 parts.

7. The application according to claim 6, wherein, By weight, The content of active elements is 1-5 parts; and / or The content of auxiliary elements is 4-8 parts; and / or The carrier content was 92-94 parts.

8. The application according to claim 1, wherein, The method for preparing the catalyst includes the following steps: (1) The carrier powder is treated at a temperature of not less than 400℃, and then the auxiliary elements are loaded onto the carrier to obtain the modified carrier; (2) The Ru-containing solution, the precipitant solution, the modified support and the aqueous solvent are subjected to a second contact, filtered and dried to obtain the hydrogenation catalyst.

9. The application according to claim 8, wherein, Step (1) includes: The modified carrier is obtained by first contacting the salt solution of the auxiliary element with the carrier, followed by aging, drying, and calcination.

10. The application according to claim 9, wherein, In step (1), the carrier is treated at 400-1100℃ for 2-8 h; and / or In step (1), the first contact is either equal-volume impregnation or excessive impregnation; and / or In step (2), the modified carrier is added to a solution containing Ru salt, and then a precipitant solution is added for a second contact.

11. The application according to claim 10, wherein, In step (1), the carrier is treated at 800-1000℃ for 2-8 h; and / or Control the pH of the second contact solution to be between 6.0 and 8.0 at the endpoint; The temperatures of the first and second contacts are each 20-90°C; and / or the durations of the first and second contacts are each 1-5 hours. The second contact takes place in the presence of a competing adsorbent; The weight ratio of the competing adsorbent to the modified support is 4-35:

100.

12. The application according to claim 11, wherein, Control the pH of the second contact solution to be 7.0-8.0 at the endpoint; The competing adsorbent is selected from one or more of citric acid, tartaric acid, lauric acid, hydrochloric acid, oxalic acid, lactic acid, and trichloroacetic acid.

13. The application according to claim 8 or 9, wherein, The salt of the auxiliary element is selected from one or more of H₂PdCl₄, PdCl₂, Zn(NO₃)₂, BBr₃, Cs₂CO₃, KOH, KNO₃, and Mg(NO₃)₂; and / or The Ru source in the Ru-containing solution is at least one of ruthenium chloride, ruthenium chlorocarboxylic acid, and ruthenium chlorocarboxate; and / or The precipitant is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, and ammonia water.

14. The application according to claim 13, wherein, The salt of the auxiliary element is selected from one or two of Cs2CO3 and Mg(NO3)2; and / or The Ru source in the Ru-containing solution is ruthenium chloride; and / or The precipitant is potassium hydroxide and / or ammonia.

15. The application according to claim 9, wherein, The concentration of the salt solution of the auxiliary element is 0.1-3.0 mol / L; and / or The concentration of the Ru-containing solution is 0.1-5.0 mol / L; and / or The concentration of the precipitant solution is 0.3-3.0 mol / L.

16. The application according to claim 15, wherein, The concentration of the salt solution of the auxiliary element is 0.3-2.0 mol / L; and / or The concentration of the Ru-containing solution is 0.5-4.0 mol / L; and / or The concentration of the precipitant solution is 0.5-1.5 mol / L.

17. A method for hydrogenating phthalate esters, characterized in that, The phthalate and hydrogen are reacted with a hydrogenation catalyst, wherein the hydrogenation catalyst comprises the catalyst according to any one of claims 1-16.

18. The method according to claim 17, wherein, The molar ratio of hydrogen to phthalate is 5:1-200:1; and / or Contact reaction conditions include: Temperature 100-250℃; and / or Pressure is 4.0-15.0 MPa; and / or The liquid hourly space velocity is 0.5-12 h⁻¹. -1 .

19. The method according to claim 18, wherein, The molar ratio of hydrogen to phthalate is 20:1-80:1; and / or Contact reaction conditions include: Temperature is 140-220℃; and / or Pressure is 7.0-13.0 MPa; and / or Liquid phase volume hourly space velocity (LHSV) is 2-8 h⁻¹ -1 .

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