Preparation method of an ethylenically unsaturated carboxylic ester selective hydrogenation catalyst and application thereof
By loading noble metals such as platinum or rhodium and additives onto γ-Al2O3, zirconium oxide, or activated carbon supports, selective hydrogenation catalysts for olefinic unsaturated carboxylic esters are prepared. This solves the problems of complete conversion and high selectivity of olefinic unsaturated carboxylic esters, reduces separation costs, and is suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-12-10
- Publication Date
- 2026-06-12
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Abstract
Description
Technical Field
[0001] This invention relates to a selective hydrogenation catalyst for olefinic unsaturated carboxylic acid esters, its preparation method, and its application, belonging to the field of catalysts. Background Technology
[0002] Saturated carboxylic acid esters are not only an important class of fine chemical synthesis intermediates that can be used in the synthesis of various chemicals or their intermediates, such as cosmetics, pharmaceuticals, and pesticides; they are also important organic solvents used in the production processes of nitrocellulose, resins, coatings, inks, paints, adhesives, and leather, with extremely wide applications.
[0003] Synthesizing specialty chemicals using bulk chemicals as raw materials not only ensures the security of raw material supply for enterprises but also typically reduces procurement and production costs significantly. Acrylic acid and its esters, as well as methyl methacrylate, are bulk chemicals with a production capacity exceeding one million tons. Using them as raw materials, saturated carboxylic acid esters can be prepared through selective hydrogenation. Patent CN107406342B discloses a method for preparing saturated alkyl esters using ethylene, carbon monoxide, and alkanols as raw materials and sulfide metal compounds as catalysts. Patent CN104761451A discloses a method for preparing propionic acid esters from propionic acid and monohydric alcohols using an exchange resin as a catalyst, achieving a methyl propionate yield of 97.2%. Patent CN112851505B discloses a process for the continuous gas-phase hydrogenation of methyl acrylate to methyl propionate. This process uses methyl acrylate containing trace amounts of polymerization inhibitors, methanol, and methyl propionate as feedstocks, achieving continuous production of methyl propionate through a hydrogenation reactor. It effectively addresses the problem of easy polymerization of methyl acrylate in continuous production but does not involve the preparation scheme of the corresponding catalyst. Patent CN111905745B discloses a catalyst for the hydrogenation reaction of methyl acrylate. This catalyst consists of a support and an active component, the active component being a composite of non-noble metals Ni, Mo, and Co, and the support being alumina. This catalyst is used under conditions where the molar ratio of methyl acrylate to hydrogen is 3–10. The amount of hydrogen required is far lower than that required for the complete hydrogenation of methyl acrylate. Although the yield of methyl propionate is high, a high conversion rate of acrylic acid cannot be achieved. Furthermore, this catalyst requires the addition of high-boiling-point hydroquinone as a polymerization inhibitor in the feedstock, which easily leads to adsorption and accumulation on the catalyst surface, affecting the catalyst's single-pass life. Patent CN117920173A discloses a method for the hydrogenation of methyl acrylate and its catalyst. This method uses palladium supported on modified silica as a catalyst, achieving a 99% conversion rate of methyl acrylate. However, this catalyst requires the presence of methanol and methyl acetate solvents, increasing the separation difficulty of the process.
[0004] The boiling points of olefinic unsaturated carboxylic esters are usually close to those of their selective hydrogenation products, resulting in high separation costs, equipment investment, and operating expenses. Therefore, achieving complete hydrogenation conversion of olefinic unsaturated carboxylic esters is the key to the low-cost industrial application of this technology. Summary of the Invention
[0005] The key to solving the above problems lies in the design and preparation of high-performance catalysts to achieve complete conversion of raw materials and high selectivity of target products.
[0006] The purpose of this invention is to address the above-mentioned problems by providing a method for preparing a selective hydrogenation catalyst for olefinic unsaturated carboxylic esters and its application in the selective hydrogenation reaction of olefinic unsaturated carboxylic esters.
[0007] According to one aspect of the present invention, a selective hydrogenation catalyst for olefinic unsaturated carboxylic acid esters is provided, the catalyst comprising a support and a noble metal active component supported on the surface of the support, an auxiliary agent A and an auxiliary agent B;
[0008] The support is selected from at least one of γ-Al2O3, zirconium oxide and activated carbon;
[0009] The noble metal active component is selected from at least one of platinum and rhodium.
[0010] The auxiliary agent A is selected from at least one of zinc, nickel, cobalt, iron and tin.
[0011] The auxiliary agent B is selected from at least one of calcium and magnesium elements;
[0012] In the selective hydrogenation catalyst, the mass ratio of the noble metal active component to the support is 0.001 to 0.002:1;
[0013] The mass ratio of additive A to carrier is 0.005–0.03:1;
[0014] The mass ratio of additive B to carrier is 0.005 to 0.03:1.
[0015] According to another aspect of the present invention, a method for preparing the above-described selective hydrogenation catalyst for olefinic unsaturated carboxylic esters is provided, comprising at least the following steps:
[0016] The support was immersed in an aqueous solution containing a noble metal active component precursor, an auxiliary agent A precursor, and an auxiliary agent B precursor, and allowed to stand. Then it was dried, calcined, and reduced with hydrogen to obtain the selective hydrogenation catalyst of the olefinic unsaturated carboxylic acid ester.
[0017] The noble metal active component precursor is selected from at least one of chloroplatinic acid, tetraammineplatinum chloride, platinum nitrate, rhodium chloride, and sodium rhodium chloride.
[0018] The precursor of the auxiliary agent A is selected from at least one of the soluble salts of zinc, nickel, cobalt, iron and tin.
[0019] The precursor of the auxiliary agent B is selected from at least one of the soluble salts of calcium and magnesium.
[0020] The drying temperature is 70–90°C;
[0021] The drying time is 4 to 20 hours.
[0022] The roasting temperature is 400–500°C;
[0023] The roasting time is 4 to 10 hours.
[0024] The temperature for hydrogen reduction is 200–400°C;
[0025] The hydrogen reduction time is 1 to 20 hours.
[0026] A method for preparing saturated carboxylic acid esters includes the following steps:
[0027] Hydrogen gas and an olefinically unsaturated carboxylic acid ester are reacted with a catalyst in a reactor to obtain a saturated carboxylic acid ester.
[0028] The catalyst is the selective hydrogenation catalyst for olefinic unsaturated carboxylic acid esters described above.
[0029] The olefinic unsaturated carboxylic ester is selected from at least one of methyl acrylate and methyl methacrylate;
[0030] At least one of the saturated carboxylic acid esters, methyl propionate and methyl isobutyrate.
[0031] The reaction temperature is 100–160°C;
[0032] The reaction is carried out at atmospheric pressure to 1 MPa.
[0033] The mass hourly space velocity (MSV) of the olefinic unsaturated carboxylic acid ester is 0.1–10 h⁻¹. -1 ;
[0034] The molar ratio of hydrogen to olefinic unsaturated carboxylic acid ester is 1.2 to 20:1.
[0035] The beneficial effects that this invention can produce include:
[0036] The selective hydrogenation catalyst for olefin-bonded unsaturated carboxylic esters provided by this invention comprises a noble metal active component, a support, and two types of promoters. The support is inexpensive and readily available, effectively dispersing the noble metal active component and providing an effective mass and heat transfer medium for the reaction. The metal active component in the catalyst plays a selective hydrogenation role, enabling hydrogenation of the unsaturated carbon-carbon bonds in the olefin-bonded unsaturated carboxylic ester while avoiding excessive hydrogenation of the carbonyl group. The promoters in the catalyst stabilize the noble metal active sites, control their grain size, improve catalyst lifetime, and suppress side reactions. This catalyst features high catalytic activity, good selectivity, and is not easily deactivated, enabling the complete conversion of olefin-bonded unsaturated carboxylic esters and significantly reducing subsequent separation costs. The preparation method of the catalyst is simple, easy to operate, and has good reproducibility, making it suitable for large-scale industrial production. Detailed Implementation
[0037] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.
[0038] Unless otherwise specified, all raw materials used in the examples are commercially available.
[0039] Example 1: Preparation of catalysts Cat.1 to Cat.9
[0040] The saturated water absorption of the carrier to be used was determined using the saturated water absorption method. Then, based on the saturated water absorption, the target loading of the noble metal active component, the target loading of additive A, and the target loading of additive B, the concentrations of the precursors of the noble metal active component, additive A, and additive B in the modified solution were calculated. Based on the above calculation results, a modified solution containing the precursors of the noble metal active component, additive A, and additive B was prepared.
[0041] The modified solution was uniformly added to the carrier until adsorption saturation, then allowed to stand at room temperature for 24 hours, dried in a vacuum oven, calcined under a nitrogen atmosphere, and finally calcined at a volume hourly space velocity of 1000 h⁻¹. -1 Reduction in a hydrogen atmosphere yields catalysts Cat.1 to Cat.9.
[0042] The preparation conditions for the catalysts, including the type of support used, the type and loading of the noble metal active component precursor (based on metal element), the type and loading of the precursor of additive A (based on metal element), the type and loading of the precursor of additive B (based on metal element), the drying temperature and drying time, the calcination temperature and calcination time, and the hydrogen reduction temperature and hydrogen reduction time, are shown in Table 1.
[0043] Table 1. Preparation conditions of catalysts Cat.1 to Cat.9
[0044]
[0045]
[0046] Comparative Example 1
[0047] Following the preparation method of Cat.2 in Example 1, but omitting the introduction of auxiliary agents A and B, the catalyst of Comparative Example 1 was prepared.
[0048] Comparative Example 2
[0049] Following the preparation method of Cat.2 in Example 1, but omitting the introduction of auxiliary agent A, catalyst for Comparative Example 2 was prepared.
[0050] Comparative Example 3
[0051] Following the preparation method of Cat.2 in Example 1, but omitting the introduction of auxiliary agent B, catalyst of Comparative Example 3 was prepared.
[0052] Example 2 Evaluation of the selective hydrogenation activity of the catalyst for olefinic unsaturated carboxylic acid esters
[0053] The hydrogenation activity of catalysts Cat.1–Cat.9 prepared in Example 1 and the comparative catalyst were evaluated using a fixed-bed reactor with an inner diameter of 9 mm and a catalyst loading of 2 mL. Methyl acrylate and hydrogen were introduced to evaluate the reaction. The products were analyzed online using an Agilent 7890A chromatograph. The catalyst activity was evaluated based on indicators such as the conversion rate of olefinically unsaturated carboxylic esters and the selectivity of saturated carboxylic esters in the feedstock. The calculation methods for each indicator are as follows:
[0054]
[0055] [Alkenyl-bonded unsaturated carboxylic acid esters] 进 Molar flow rate (mol / h) of the olefinically unsaturated carboxylic acid ester at the reactor inlet; [olefinically unsaturated carboxylic acid ester] 出 and [saturated carboxylic acid esters] 出 The values represent the molar flow rates (mol / h) of olefinically unsaturated carboxylic esters and saturated carboxylic esters at the reactor outlet, respectively. The catalysts, reaction conditions, and catalyst activities for experiments exp1–exp12 are shown in Table 2.
[0056] Table 2. Reaction conditions and catalyst activity for experiments exp1-exp12
[0057]
[0058]
[0059] In the experiments shown in Table 2, samples were taken and analyzed every 5 hours. The results in the table are the average values over 50 hours. Experiment exp2 was run continuously for 4000 hours, and no significant decrease in conversion or selectivity was observed, indicating that the catalyst has good stability.
[0060] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A selective hydrogenation catalyst for olefinically unsaturated carboxylic acid esters, characterized in that, The selective hydrogenation catalyst for olefinic unsaturated carboxylic acid esters is composed of a support and a noble metal active component supported on the surface of the support, an auxiliary agent A, and an auxiliary agent B. The support is selected from at least one of γ-Al2O3, zirconium oxide and activated carbon; The noble metal active component is selected from at least one of platinum and rhodium. The auxiliary agent A is selected from at least one of zinc, nickel, cobalt, iron and tin. The auxiliary agent B is selected from at least one of calcium and magnesium elements; In the selective hydrogenation catalyst for olefinic unsaturated carboxylic acid esters, the mass ratio of the noble metal active component to the support is 0.001–0.002:
1. The mass ratio of additive A to carrier is 0.005–0.03:1; The mass ratio of additive B to carrier is 0.005 to 0.03:
1.
2. A method for preparing the selective hydrogenation catalyst of olefinic unsaturated carboxylic acid esters according to claim 1, characterized in that, At least the following steps are included: The support was immersed in an aqueous solution containing a noble metal active component precursor, an auxiliary agent A precursor, and an auxiliary agent B precursor, and allowed to stand. Then it was dried, calcined, and reduced with hydrogen to obtain the selective hydrogenation catalyst of the olefinic unsaturated carboxylic acid ester.
3. The preparation method according to claim 2, characterized in that, The noble metal active component precursor is selected from at least one of chloroplatinic acid, tetraammineplatinum chloride, platinum nitrate, rhodium chloride, and sodium rhodium chloride. The precursor of the auxiliary agent A is selected from at least one of the soluble salts of zinc, nickel, cobalt, iron and tin. The precursor of the auxiliary agent B is selected from at least one of the soluble salts of calcium and magnesium.
4. The preparation method according to claim 2, characterized in that, The drying temperature is 70–90°C; The drying time is 4 to 20 hours.
5. The preparation method according to claim 2, characterized in that, The roasting temperature is 400–500°C; The roasting time is 2 to 10 hours.
6. The preparation method according to claim 2, characterized in that, The temperature for hydrogen reduction is 200–400°C; The hydrogen reduction time is 1 to 20 hours.
7. A method for preparing saturated carboxylic acid esters, characterized in that, Includes the following steps: Hydrogen gas and an olefinically unsaturated carboxylic acid ester are reacted with a catalyst in a reactor to obtain a saturated carboxylic acid ester. The catalyst is the selective hydrogenation catalyst for olefinic unsaturated carboxylic acid esters as described in claim 1.
8. The method according to claim 7, characterized in that, The olefinic unsaturated carboxylic ester is selected from at least one of methyl acrylate and methyl methacrylate; At least one of the saturated carboxylic acid esters, methyl propionate and methyl isobutyrate.
9. The method according to claim 7, characterized in that, The reaction temperature is 100–160°C; The reaction is carried out at atmospheric pressure to 1 MPa.
10. The method according to claim 7, characterized in that, The mass hourly space velocity (MSV) of the olefinic unsaturated carboxylic acid ester is 0.1–10 h⁻¹. -1 ; The molar ratio of hydrogen to olefinic unsaturated carboxylic acid ester is 1.2 to 20:1.