Hydrogenation catalysts, processes for their preparation and use and processes for the synthesis of cyclohexanedicarboxylic esters

Abstract

The present application relates to the field of cyclohexane dimethyl acid ester preparation, in particular to a hydrogenation catalyst, a preparation method and application thereof, and a cyclohexane dimethyl acid ester synthesis method.The hydrogenation catalyst contains a carrier, and active elements and auxiliary elements loaded on the carrier, the active elements are selected from Ru, the auxiliary elements are selected from one or more of Pd, Re, Ag, Zr, K and Ca, the Ru 3p3 / 2 binding energy of the hydrogenation catalyst is 464-461eV, the hydrogenation catalyst has an absorption vibration peak of 1990-2015cm ‑1 of CO-DRIFTS infrared wave number.The hydrogenation catalyst provided by the present application is used for preparing cyclohexane dimethyl acid ester by hydrogenation of phthalic acid ester, improves the phthalic acid ester conversion rate, reduces the generation of carbonyl hydrogenation by-products, and improves the total selectivity of cyclohexane dimethyl acid ester.

Description

Technical Field

[0001] This invention relates to the field of cyclohexanedicarboxylate preparation, specifically to a hydrogenation catalyst, its preparation method and application, and a method for synthesizing cyclohexanedicarboxylate. Background Technology

[0002] 1,4-Cyclohexanediethanol (CHDM) is an important intermediate used in the synthesis of various high-performance polyester materials (PETG, PCTG, etc.). With the development of the downstream polyester industry, the demand for CHDM in the domestic market will continue to increase in the future.

[0003] CN1099745A and CN1058959C disclose a low-pressure method for producing dimethyl 1,4-cyclohexanedicarboxylate (DMCD) by hydrogenation of dimethyl terephthalate (DMT). In this method, a mixed liquid containing DMT and DMCD (DMT / DMCD = 3:7 by weight) is continuously fed into a fixed-bed reactor and reacted with hydrogen under the action of a Pd / Al₂O₃ catalyst. The reaction is carried out at a pressure of 4–14 MPa, a temperature of 160–220 °C, and a liquid hourly space velocity (LHSV) of 0.5–2 / h. The patents specifically mention that the low-pressure hydrogenation process (<17.5 MPa) generates CO gas, which reduces the activity of Pd-based catalysts. The tolerance concentration of CO gas for heavy metal catalysts such as Pd is 500 ppmv, preferably 100 ppmv. To limit the effect of carbon monoxide on catalyst activity, the patents describe a method for venting CO-containing purge hydrogen gas at a rate of 8–10 L / min, thereby reducing the carbon monoxide content in the reaction system. However, directly releasing hydrogen gas will increase costs. If the hydrogen effluent is subjected to cryogenic or pressure swing adsorption (PSA) treatment, energy consumption and treatment costs will increase.

[0004] CN1398841A describes a method for preparing 1,4-cyclohexanediethanol from dimethyl 1,4-cyclohexanedicarboxylate using a copper oxide-based hydrogenation catalyst at an operating pressure of 6.0 MPa and a temperature of 240 °C. CN105688915B discloses a method for preparing 1,4-cyclohexanediethanol from dimethyl terephthalate, where the first-stage hydrogenation product is directly fed into the second-stage hydrogenation without further treatment. The resulting acidic byproducts can affect the activity of the Cu-based catalyst. Furthermore, the second-stage hydrogenation operates at a relatively high pressure (7–9 MPa), temperature (245–255 °C), liquid hourly space velocity (LHSV) of 0.5–0.7 h, and a hydrogen-to-ester ratio of 500–1200. The high operating pressure of existing second-stage hydrogenation technologies leads to increased energy consumption and significantly higher investment in industrial-scale equipment. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the low conversion rate and selectivity of phthalate hydrogenation to cyclohexanedicarboxylate in the prior art, and to provide a hydrogenation catalyst that can produce cyclohexanedicarboxylate with high selectivity.

[0006] To achieve the above objectives, a first aspect of the present invention provides a hydrogenation catalyst comprising a support and an active element and a promoter element supported on the support, wherein the active element is selected from Ru; the promoter element is selected from one or more of Pd, Re, Ag, Zr, K, and Ca; the Ru 3p3 / 2 binding energy in the hydrogenation catalyst is 464-461 eV; and the hydrogenation catalyst has a CO-DRIFTS infrared wavenumber of 1990-2015 cm⁻¹. -1 The absorption vibration peak.

[0007] A second aspect of the present invention provides a method for preparing the hydrogenation catalyst of the present invention, the method comprising the following steps:

[0008] (1) Loading the auxiliary elements onto the support to obtain the modified support;

[0009] (2) The Ru-containing source solution, the precipitant solution, and the modified support are subjected to a second contact in solution, and then filtered and dried to obtain the hydrogenation catalyst.

[0010] A third aspect of the present invention provides the application of the hydrogenation catalyst described herein in the hydrogenation of phenyl dicarboxylic acid ester to cyclohexane dicarboxylic acid ester.

[0011] The fourth aspect of the present invention provides a method for synthesizing cyclohexanedicarboxylate, wherein phthalate and hydrogen are reacted with the hydrogenation catalyst in the presence of the hydrogenation catalyst described in the present invention.

[0012] The effects of the active sites of existing hydrogenation catalysts on Ru-based catalysts are mainly reflected in: (1) the catalyst active sites have insufficient adsorption capacity for reactant molecules, which leads to unsatisfactory conversion rate during the reaction; (2) the catalyst active sites have strong adsorption capacity for subgroup molecules, which leads to the generation of byproducts in hydrogenation side reactions.

[0013] The hydrogenation catalyst provided by this invention increases the Ru 3p3 / 2 binding energy in the catalyst, thereby enhancing the adsorption capacity for benzene ring groups; it also lowers the position of the CO-DRIFTS infrared wavenumber peak in the hydrogenation catalyst, thereby suppressing and reducing the adsorption capacity of the carbonyl subgroup; the combination of these two factors achieves both improved conversion rate and enhanced overall selectivity of the target product.

[0014] The hydrogenation catalyst provided by this invention is used for the hydrogenation of phthalate to prepare cyclohexanedicarboxylate, which improves the conversion rate of phthalate while reducing the formation of carbonyl hydrogenation byproducts and improving the overall selectivity of cyclohexanedicarboxylate. Attached Figure Description

[0015] Figure 1 These are XPS images of the hydrogenation catalysts prepared in Example 1 and Comparative Example 1;

[0016] Figure 2 These are CO-DRIFTS spectra of the hydrogenation catalysts prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0017] 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.

[0018] The first aspect of the present invention provides a hydrogenation catalyst comprising a support and an active element and an auxiliary element supported on the support, wherein the active element is selected from Ru; and the auxiliary element is selected from one or more of Pd, Re, Ag, Zr, K and Ca.

[0019] The Ru 3p3 / 2 binding energy in the hydrogenation catalyst is 464-461 eV; the hydrogenation catalyst has a CO-DRIFTS infrared wavenumber of 1990-2015 cm⁻¹. -1 The absorption vibration peaks are observed. The hydrogenation catalyst provided by this invention increases the Ru 3p3 / 2 binding energy in the catalyst, thereby enhancing the adsorption capacity for benzene ring groups; it also lowers the position of the CO-DRIFTS infrared wavenumber peak in the hydrogenation catalyst, thereby suppressing and reducing the adsorption capacity of the carbonyl subgroup; the combination of these two factors improves both the conversion rate and the overall selectivity of the target product.

[0020] According to a preferred embodiment of the present invention, the binding energy of Ru 3p3 / 2 in the hydrogenation catalyst is 464-462 eV.

[0021] According to a preferred embodiment of the present invention, the CO-DRIFTS infrared wavenumber of the hydrogenation catalyst is 1990-2000 cm⁻¹. -1 .

[0022] In this invention, 1990-2015cm -1 For CO in Ru 0 The upper linear adsorption vibration peak.

[0023] According to a preferred embodiment of the present invention, the hydrogenation catalyst has a CO-DRIFTS infrared wavenumber of 2060-2080 cm⁻¹. -1The absorption vibration peak, 2060-2080 cm⁻¹ -1 For CO in Ru δ+ The adsorption vibration peak on the surface.

[0024] According to a preferred embodiment of the present invention, the hydrogenation catalyst has a CO-DRIFTS infrared wavenumber of 2100-2140 cm⁻¹. -1 The absorption vibration peak, 2100-2140 cm⁻¹ -1 For multiple COs in Ru δ+ Upper absorption peak.

[0025] According to a preferred embodiment of the present invention, the auxiliary element is selected from one or more of Pd, Zr and Ca, preferably Zr and Ca, and more preferably the weight ratio of Zr to Ca is 2-8:3.

[0026] 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.

[0027] According to a preferred embodiment of the present invention, the content of active elements is 0.1-35 parts by weight, preferably 0.5-20 parts, more preferably 1-10 parts, and even more preferably 2-3 parts.

[0028] According to a preferred embodiment of the present invention, the auxiliary element is 0.5-50 parts by weight, preferably 1-40 parts, more preferably 2-30 parts, and even more preferably 5-11 parts.

[0029] According to a preferred embodiment of the present invention, the carrier content is 10-96 parts by weight, preferably 30-94 parts, more preferably 50-92 parts, and even more preferably 80-91 parts.

[0030] In this invention, the catalyst content is determined by ICP.

[0031] In this invention, hydrogenation catalysts possessing the aforementioned characteristics can all achieve the objectives of this invention. There are no particular limitations on the preparation method of the hydrogenation catalyst. According to a preferred embodiment of this invention, a method for preparing the aforementioned hydrogenation catalyst is provided, comprising the following steps:

[0032] (1) Loading the auxiliary elements onto the support to obtain the modified support;

[0033] (2) The Ru-containing source solution, the precipitant solution, and the modified support are subjected to a second contact in solution, and then filtered and dried to obtain the hydrogenation catalyst.

[0034] According to a preferred embodiment of the present invention, in step (1), the salt solution of the auxiliary element and the carrier are subjected to a first contact impregnation loading, and then aged, dried and calcined to obtain a modified carrier; preferably, the first contact impregnation loading is an equal volume impregnation or an excessive impregnation; preferably, the concentration of the salt solution of the auxiliary element is 0.1-3.0 mol / L, more preferably 0.3-2.0 mol / L.

[0035] According to a preferred embodiment of the present invention, the temperature of the first contact is 20-90°C, and the contact time is 1-5 hours.

[0036] According to a preferred embodiment of the present invention, in step (1), the aging temperature is room temperature - 80°C, and the aging time is adjusted reasonably according to the temperature. Preferably, the aging time is 1-10h, and more preferably, the aging time is 2-5h.

[0037] In this invention, there are no particular limitations on the drying conditions in step (1), as long as the solvent can be removed.

[0038] 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 400-1100℃, and the calcination time is adjusted reasonably according to the temperature. Preferably, the calcination time is 2-8h.

[0039] According to a preferred embodiment of the present invention, the modified carrier is added to a Ru-containing source solution, and then a precipitant solution is added for a second contact.

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

[0041] 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.

[0042] According to a preferred embodiment of the present invention, the temperature of the second contact is 20-90°C, and the contact time is reasonably adjusted according to the contact temperature. Preferably, the contact time of the second contact is 1-5 hours.

[0043] According to a preferred embodiment of the present invention, in step (2), after the second contact, aging is performed, followed by filtration, washing, and drying to obtain the hydrogenation catalyst product; preferably, the aging temperature is room temperature to 80°C, and the aging time is adjusted reasonably according to the aging temperature, preferably, the aging time is 1-10h.

[0044] 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, preferably a mixture of citric acid and oxalic acid, and more preferably a mass ratio of citric acid to oxalic acid of 0.1-10:1.

[0045] According to a preferred embodiment of the present invention, the weight ratio of the competing adsorbent to the modified carrier is preferably 3-30:100.

[0046] 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, rhenium chloride, perrhenate, AgNO3, AgCl, KOH, KNO3, Zr(NO3)4, and Ca(NO3)2, and more preferably from one or more of H2PdCl4, Zr(NO3)4 and Ca(NO3)2.

[0047] In this invention, there is no particular limitation on the type of Ru source, which can be any Ru source conventional in the art. Preferably, the Ru source in the Ru source-containing solution is at least one of ruthenium chloride, ruthenium chloride acid and ruthenium chloride salt, preferably ruthenium chloride.

[0048] In this invention, there is no particular limitation on the type of 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.

[0049] According to a preferred embodiment of the present invention, the concentration of the Ru-containing source solution is 0.1-5.0 mol / L, preferably 0.5-4.0 mol / L.

[0050] 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.

[0051] According to a third aspect of the present invention, the present invention provides the application of the hydrogenation catalyst described herein in the hydrogenation of phenyl dicarboxylate to cyclohexanedicarboxylate, preferably in the hydrogenation of dimethyl terephthalate to dimethyl 1,4-cyclohexanedicarboxylate.

[0052] According to a fourth aspect of the present invention, a method for synthesizing cyclohexanedicarboxylate is provided, wherein phthalate and hydrogen are reacted with the hydrogenation catalyst in the presence of the hydrogenation catalyst described herein. The hydrogenation catalyst provided by the present invention is used for the hydrogenation of phthalate to prepare cyclohexanedicarboxylate, improving the conversion rate of phthalate while reducing the formation of carbonyl hydrogenation byproducts, and improving the overall selectivity of cyclohexanedicarboxylate.

[0053] 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, which is beneficial to improving the raw material conversion rate and the overall selectivity of cyclohexanedicarboxylate.

[0054] 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 Under these contact reaction conditions, it is beneficial to improve the conversion rate of raw materials and the overall selectivity of cyclohexanedicarboxylate.

[0055] In this invention, the position of the Ru 3p3 / 2 binding energy peak represents the different adsorption capacities of the active component ruthenium for benzene ring groups and carbonyl groups, and is used to compare the adsorption capacities of reactant group molecules between different samples. An increased Ru 3p3 / 2 binding energy in the catalyst enhances the adsorption capacity for benzene ring groups, thereby improving the conversion rate of phthalate esters.

[0056] In this invention, the position of the CO-DRIFTS infrared wavenumber peak represents the different adsorption capacities of the active component ruthenium for carbonyl groups, and is used to compare the adsorption capacities of different samples for reactant carbonyl molecules. A lower CO-DRIFTS infrared wavenumber peak position in the catalyst can inhibit and reduce the adsorption capacity of the secondary carbonyl groups, reduce side reactions, and thus improve the selectivity of the target product.

[0057] The present invention will be described in detail below through embodiments.

[0058] In this invention, the conversion and selectivity of dimethyl terephthalate (DMT) hydrogenation to dimethyl 1,4-cyclohexanedicarboxylate (DMCD) are calculated using the following formulas:

[0059]

[0060]

[0061] In the formula: n – amount of substance, in mol; DMT – dimethyl terephthalate; DMCD – dimethyl 1,4-cyclohexanedicarboxylate; 1 – raw material; 2 – product.

[0062] Test method:

[0063] In the following examples, the dimethyl terephthalate used was industrial grade, dissolved in dimethyl 1,4-cyclohexanedicarboxylate, with a dimethyl terephthalate mass fraction of 5% and a dimethyl 1,4-cyclohexanedicarboxylate mass fraction of 95%; the hydrogen gas used had an integral of 99.9%.

[0064] The binding energy of Ru 3p3 / 2 in the hydrogenation catalyst was measured using X-ray photoelectron spectroscopy (XPS). An increased binding energy indicates a decrease in the electron cloud density of the Ru particles, which is beneficial for the adsorption of the benzene ring (equivalent to a large π bond, an electron-rich group) at the Ru active site, thereby promoting the benzene ring hydrogenation reaction.

[0065] The CO infrared wavenumber of the hydrogenation catalyst was measured using a CO Fourier transform infrared (CO-DRIFTS) instrument. (1990-2015 cm⁻¹) -1 For CO in Ru 0 Upper linear adsorption vibration peak, 2060-2080 cm⁻¹ -1 For CO in Ru δ+ The adsorption vibration peaks on the surface are 2100-2140 cm⁻¹. -1 For multiple COs in Ru δ+ The absorption peak shifts to lower wavenumbers, indicating CO-Ru absorption. 0 Ru(CO)X m Ru(CO) n X m The reduction in adsorption sites decreases the adsorption of ester groups and the hydrogenation side reaction, which helps to improve catalyst selectivity.

[0066] In the following examples, the content of each component of the catalyst was determined by ICP.

[0067] Example 1

[0068] 1) Catalyst preparation:

[0069] (1) Prepare an aqueous solution I with a concentration of 0.8 mol / L by mixing the auxiliary salts Zr(NO3)4 and Ca(NO3)2; add 12 g of alumina carrier pseudoboehmite to the aqueous solution containing the auxiliary salts by equal volume impregnation, and make the first contact at a temperature of 25°C for 1 h. Stir evenly, age at 25°C for 3 h, then dry at 120°C for 12 h, and calcine at 600°C for 4 h to obtain the modified alumina;

[0070] (2) Prepare a 0.8 mol / L aqueous solution II of ruthenium chloride; prepare a 1.0 mol / L aqueous solution III of potassium hydroxide as a precipitant. 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 dropwise to control the pH at the endpoint to 7.5. Aging at 25℃ for 4 hours, filter, wash, and dry to obtain the hydrogenation catalyst product. In the hydrogenation catalyst, the content of Ru is 2 parts, the content of Zr is 4 parts, the content of Ca is 3 parts, and the content of alumina support is 91 parts.

[0071] Figure 1 The image shows the XPS plot of the catalyst prepared in Example 1, with a Ru 3p3 / 2 binding energy of 462.1 eV.

[0072] Figure 2 The image shows the CO-DRIFTS diagram of the catalyst prepared in Example 1, Ru 0 The linear adsorption infrared wavenumber for CO was 1991 cm⁻¹. -1 .

[0073] 2) Catalyst reduction:

[0074] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0075] 3) Catalytic hydrogenation:

[0076] 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 97.6%.

[0077] Example 2

[0078] (1) Prepare a solution I with a concentration of 0.6 mol / L by mixing the auxiliary salts Zr(NO3)4 and Ca(NO3)2; add the carrier to the solution containing the auxiliary salts by impregnation with equal volume, and make the first contact at a temperature of 50°C for 1 hour. Stir evenly, age for 3 hours, dry at 120°C for 12 hours, and calcine at 600°C for 4 hours to obtain the modified alumina.

[0079] (2) 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 0.5 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℃, the time is 3 hours, and the pH at the endpoint is controlled to be 7.5. Aging is performed for 4 hours, followed by filtration, washing, and drying to obtain the hydrogenation catalyst product. The hydrogenation catalyst contains 2 parts Ru, 2 parts Zr, 3 parts Ca, and 93 parts alumina support.

[0080] 2) Catalyst reduction:

[0081] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0082] 3) Catalytic hydrogenation:

[0083] 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 97.1%.

[0084] Example 3

[0085] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the content of Zr was different. In the hydrogenation catalyst, the content of Ru was 2 parts, the content of Zr was 8 parts, the content of Ca was 3 parts, and the content of alumina support was 87 parts.

[0086] 2) Catalyst reduction:

[0087] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0088] 3) Catalytic hydrogenation:

[0089] 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 97.4%.

[0090] Example 4

[0091] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the contents of Zr and Ca were different. In the hydrogenation catalyst, the contents of Ru were 2 parts, Zr were 6 parts, Ca were 1 part, and alumina support were 91 parts.

[0092] 2) Catalyst reduction:

[0093] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0094] 3) Catalytic hydrogenation:

[0095] 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 97.5%.

[0096] Example 5

[0097] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the types of additives were different. In the hydrogenation catalyst, the content of Ru was 2 parts, the content of Pd was 0.5 parts, the content of Zr was 4 parts, the content of Ca was 3 parts, and the content of alumina support was 90.5 parts.

[0098] 2) Catalyst reduction:

[0099] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0100] 3) Catalytic hydrogenation:

[0101] 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 97.6%.

[0102] Example 6

[0103] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the types and contents of the additives were different. In the hydrogenation catalyst, the Ru content was 2 parts, the Ag content was 0.5 parts, the K content was 3 parts, and the alumina support content was 94.5 parts.

[0104] 2) Catalyst reduction:

[0105] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0106] 3) Catalytic hydrogenation:

[0107] 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 98.3%, and the DMCD selectivity was 96.7%.

[0108] Example 7

[0109] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the component contents were different. In the hydrogenation catalyst, the Ru content was 0.8 parts, the Zr content was 0.4 parts, the Ca content was 1.5 parts, and the alumina support content was 97.3 parts.

[0110] 2) Catalyst reduction:

[0111] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0112] 3) Catalytic hydrogenation:

[0113] 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 93.4%, and the DMCD selectivity was 95.8%.

[0114] Example 8

[0115] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the component contents were different. In the hydrogenation catalyst, the Ru content was 2 parts, the Zr content was 15 parts, the Ca content was 20 parts, and the alumina support content was 63 parts.

[0116] 2) Catalyst reduction:

[0117] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0118] 3) Catalytic hydrogenation:

[0119] 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 97.1%, and the DMCD selectivity was 94.3%.

[0120] Example 9

[0121] The hydrogenation catalyst was prepared using the same method as in Example 1, with the difference being that the hydrogenation reaction conditions were different. In step 3), the reaction temperature was 130°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 93.2%, and the DMCD selectivity was 96.5%.

[0122] Example 10

[0123] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, with the difference being: in step (2), citric acid was added as a competitive adsorbent in the second contact, and the weight ratio of citric acid to the modified support was 20:100. The impregnation solution II was first mixed with the competitive adsorbent, and then the modified alumina support was added to the mixture.

[0124] 2) Catalyst reduction:

[0125] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0126] 3) Catalytic hydrogenation:

[0127] 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 98.8%.

[0128] Example 11

[0129] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, with the difference being: in step (2), citric acid and oxalic acid were added as competitive adsorbents in the second contact, with the weight ratio of citric acid, oxalic acid and modified support being 10:10:100. The impregnation solution II was first mixed with the competitive adsorbents, and then the modified alumina support was added to the mixture.

[0130] 2) Catalyst reduction:

[0131] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0132] 3) Catalytic hydrogenation:

[0133] 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 98.5%.

[0134] Comparative Example 1

[0135] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that: it does not contain Zr and Ca, the Ru content in the hydrogenation catalyst component is 2 parts, and the alumina support content is 98 parts.

[0136] Figure 1 The XPS plot of the catalyst prepared in Comparative Example 1 shows that the Ru 3p3 / 2 binding energy is 460.9 eV.

[0137] Figure 2 The image shows the CO-DRIFTS diagram of the catalyst prepared in Comparative Example 1. (Ru) 0 The linear adsorption infrared wavenumber for CO was 2016 cm⁻¹. -1 .

[0138] 2) Catalyst reduction:

[0139] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0140] 3) Catalytic hydrogenation:

[0141] 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 91.8%, and the DMCD selectivity was 96.3%.

[0142] Comparative Example 2

[0143] 1) The hydrogenation catalyst was prepared using the preparation method of the hydrogenation catalyst in Example 1, except that the types and contents of the additives were different. In the hydrogenation catalyst, the Ru content was 2 parts, the Mn content was 5 parts, and the alumina support content was 92 parts.

[0144] The XPS results for the prepared catalyst show that the Ru 3p3 / 2 binding energy is 459.2 eV.

[0145] 2) Catalyst reduction:

[0146] 10g of catalyst, 20mL of catalyst loading, pure hydrogen gas, reduction at 200℃ for 10h.

[0147] 3) Catalytic hydrogenation:

[0148] 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 67.3%, and the DMCD selectivity was 91.4%.

[0149] Table 1

[0150]

[0151]

[0152] Figure 1 The above are XPS images of the hydrogenation catalysts prepared in Example 1 and Comparative Example 1, showing that the addition of Zr and Ca electron promoters is beneficial to increasing the Ru 3p3 / 2 binding energy of the catalyst, reducing the electron cloud density of Ru particles, which is conducive to the adsorption of benzene rings (equivalent to large π bonds, electron-rich groups) on Ru active sites, thereby promoting the hydrogenation reaction of phthalate esters.

[0153] Figure 2 These are the CO-DRIFTS spectra of the hydrogenation catalysts prepared in Example 1 and Comparative Example 1, demonstrating that the addition of the promoters Zr and Ca electronic promoters is beneficial in reducing CO concentration in Ru. 0 Upper linear adsorption, CO in Ru δ+ Adsorption on Ru, multiple CO in Ru δ+ The infrared wavenumber absorbed on the upper surface makes CO-Ru 0 Ru(CO)X m Ru(CO) n X m The reduction in adsorption sites can decrease the adsorption of ester groups and hydrogenation side reactions, which helps to improve the selectivity of catalytic reactions to produce cyclohexanedicarboxylate.

[0154] As can be seen from the results in Table 1, the hydrogenation catalyst provided by this invention can significantly improve the conversion rate and the selectivity of the product when used for the hydrogenation of phthalate to prepare cyclohexanedicarboxylate.

[0155] 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. A hydrogenation catalyst for hydrogenating a benzenedicarboxylic acid ester to a cyclohexanedicarboxylic acid ester, characterized by, The hydrogenation catalyst contains a carrier and active elements and auxiliary elements supported on the carrier, the active elements are selected from Ru; the auxiliary elements are selected from one or more of Pd, Zr and Ca; the content of the active elements is 0.1-35 parts by weight; the content of the auxiliary elements is 0.5-50 parts; the content of the carrier is 10-96 parts; the Ru 3p 3 / 2 binding energy is 464-461 eV; the hydrogenation catalyst has an absorption vibration peak of CO-DRIFTS infrared wave number of 1990-2015 cm -1 .

2. The hydrogenation catalyst according to claim 1, wherein, The hydrogenation catalyst has an absorption vibration peak at a CO-DRIFTS infrared wave number of 1990-2000 cm -1 ; and / or The auxiliary elements are Zr and Ca; and / or The carrier is selected from at least one of alumina, silica, and molecular sieve.

3. The hydrogenation catalyst according to claim 2, wherein, The weight ratio of Zr to Ca is 2-8:3; and / or The carrier is aluminum oxide.

4. The hydrogenation catalyst of claim 1, wherein, By weight, The content of active elements is 0.5~20 parts; and / or The content of auxiliary elements is 1-40 parts; and / or The carrier content is 30-94 parts.

5. The hydrogenation catalyst of claim 1, wherein, By weight, The content of active elements is 1-10 parts; and / or The content of auxiliary elements is 2-30 parts; and / or The carrier content is 50-92 parts.

6. The hydrogenation catalyst of claim 1, wherein, By weight, The content of active elements is 2-3 parts; and / or The content of auxiliary elements is 5-11 parts; and / or The carrier content is 80-91 parts.

7. A process for the preparation of a hydrogenation catalyst as claimed in any one of claims 1 to 6, characterized in that The method includes the following steps: (1) Loading the auxiliary elements onto the support to obtain the modified support; (2) The Ru-containing source solution, the precipitant solution, and the modified support are subjected to a second contact in solution, and then filtered and dried to obtain the hydrogenation catalyst.

8. The preparation method according to claim 7, wherein, In step (1), the salt solution of the auxiliary element and the carrier are subjected to first contact impregnation and loading, followed by aging, drying, and calcination to obtain the modified carrier; and / or In step (2), the modified carrier is added to a Ru-containing source solution, followed by the addition of a precipitant solution for a second contact; and / or In step (2), the final pH of the second contact solution is controlled to be 6.0-8.0; and / or In step (2), the temperature of the second contact is 20-90°C, and / or the time of the second contact is 1-5h.

9. The preparation method according to claim 8, wherein, The first contact impregnation load is either equal-volume impregnation or excessive impregnation; and / or The concentration of the salt solution of the auxiliary element is 0.1-3.0 mol / L; and / or The temperature of the first contact is 20-90℃, and the contact time is 1-5 hours; and / or In step (2), the pH of the second contact solution endpoint is controlled to be 7.0-8.

0.

10. The preparation method according to claim 8, wherein, The concentration of the salt solution of the auxiliary element is 0.3-2.0 mol / L.

11. The preparation method according to claim 7 or 8, wherein, The salt of the auxiliary element is selected from one or more of H2PdCl4, PdCl2, Zr(NO3)4, and Ca(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; and / or The second contact takes place in the presence of a competing adsorbent.

12. The preparation method according to claim 11, wherein, The salt of the auxiliary element is selected from one or more of H2PdCl4, Zr(NO3)4, and Ca(NO3)2; and / or The Ru source in the Ru-containing solution is ruthenium chloride; and / or The precipitant is selected from potassium hydroxide and / or ammonia; and / or 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; and / or The weight ratio of the competing adsorbent to the modified support is 3-30:

100.

13. The preparation method according to claim 7 or 8, wherein, The concentration of the Ru-containing source solution is 0.1-5.0 mol / L; and / or The concentration of the precipitant solution is 0.3-3.0 mol / L.

14. The preparation method according to claim 13, wherein, The concentration of the Ru-containing source solution is 0.5-4.0 mol / L; and / or The concentration of the precipitant solution is 0.5-1.5 mol / L.

15. The use of the hydrogenation catalyst according to any one of claims 1-6 in the hydrogenation of phenyl dicarboxylic acid ester to cyclohexane dicarboxylic acid ester.

16. A method of synthesizing cyclohexane dicarboxylate esters, characterized by, In the presence of the hydrogenation catalyst according to any one of claims 1-6, phthalate and hydrogen are reacted with the hydrogenation catalyst.

17. The method according to claim 16, 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 Liquid hourly space velocity of 0.5 to 12 hours -1 .

18. The method according to claim 17, 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 hourly space velocity of 2 to 8 hours -1 .

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