Alumina supported pd for anthraquinone hydrogenation x Process for the preparation of s catalysts and their use

Abstract

This invention relates to the field of anthraquinone hydrogenation catalyst technology, and specifically discloses an alumina-supported Pd catalyst for anthraquinone hydrogenation. x The preparation method and application of S catalyst include: impregnating an alumina support in a mixed solution containing a Pd precursor and a sulfur source, drying, and heat treatment under a gas atmosphere to finally obtain a catalyst using industrial alumina as a support and Pd as a precursor. x S is an alumina-supported Pd active component. x S catalyst. The above catalyst exhibits excellent catalytic activity, high selectivity, and strong stability, enabling it to more effectively catalyze the hydrogenation reaction of anthraquinone. Furthermore, the preparation method is simple, low-cost, and easily scaled up.

Description

Technical Field

[0001] This invention belongs to the field of anthraquinone hydrogenation catalyst technology, specifically relating to an alumina-supported Pd catalyst for anthraquinone hydrogenation. x Preparation methods and applications of S catalysts. Background Technology

[0002] Hydrogen peroxide (H₂O₂), a strong oxidizing and green chemical product, is widely recognized as one of the cleanest and greenest basic chemical raw materials because its final product is only water. Due to its environmentally friendly production process, it has wide applications in papermaking, bleaching, and chemical synthesis. Currently, the main industrial methods for producing hydrogen peroxide are the anthraquinone hydrogenation method and the electrolysis method. Compared to the electrolysis method, the anthraquinone method has significant advantages such as low energy consumption, lower cost, and ease of large-scale industrial production, and has become the mainstream hydrogen peroxide production technology globally.

[0003] In the anthraquinone process, anthraquinone hydrogenation is a crucial step in generating hydrogen peroxide. Currently, palladium (Pd)-based catalysts are commonly used in this step. Among them, metal-supported Pd-based catalysts, represented by Pd / Al₂O₃, dominate the anthraquinone hydrogenation process due to their high activity, low dosage, operational safety, and excellent cycle performance. As a high-performance support, alumina (Al₂O₃) possesses abundant crystal forms and controllable microstructures, providing efficient pore structures and high mechanical strength. By adjusting the preparation process, its specific surface area, pore volume, and pore size distribution can be flexibly controlled to meet the loading requirements of different active components and the mass transfer and diffusion requirements of the reaction. Therefore, the continuous improvement and optimization of metal-supported Pd-based catalysts, especially enhancing their selectivity and activity in anthraquinone hydrogenation, is a key focus of research both domestically and internationally.

[0004] However, there is still room for improvement in existing technologies. For example, Chinese patent CN 104549246 A discloses a palladium-based hydrogenation catalyst and its application in anthraquinone hydrogenation, using a zirconium dioxide and activated alumina composite oxide as a support. However, its hydrogenation efficiency in the anthraquinone hydrogenation reaction still needs to be improved. Another Chinese patent CN110433824 A discloses an anthraquinone hydrogenation catalyst and its preparation method, specifically using an impregnation method to load nano-cobalt oxide onto an alumina support, and then using a sol-gel method to load palladium onto the catalyst. However, this method has a long preparation cycle.

[0005] Therefore, developing anthraquinone hydrogenation palladium-based catalysts that combine high hydrogenation efficiency with relatively simple preparation processes is of great significance for improving the economics and competitiveness of hydrogen peroxide production technology, and is also a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention discloses an alumina-supported Pd for anthraquinone hydrogenation. x Preparation methods and applications of sulfur catalysts, including in-situ sulfidation of Pd from inorganic or organic sulfur sources. x A method using an S / Al₂O₃ catalyst addresses the problems of high toxicity and hazardous operation associated with hydrogen sulfide gas in existing technologies. This catalyst not only has a simple preparation method but also significantly improves the hydrogenation efficiency of anthraquinone.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] The first aspect of this invention provides an alumina-supported Pd for anthraquinone hydrogenation. x The preparation method of S catalyst includes the following steps:

[0009] (1) Prepare a mixed solution containing Pd precursor and sulfur source, add alumina support to the mixed solution, impregnate and dry to obtain catalyst precursor;

[0010] (2) The catalyst precursor is heat-treated in a reaction atmosphere to obtain the alumina-supported Pd. x S catalyst.

[0011] Preferably, in step (1), the preparation process of the mixed solution containing Pd precursor and sulfur source includes: dissolving Pd precursor in water beforehand, adding sulfur source, stirring until completely dissolved, and obtaining a homogeneous mixed solution.

[0012] Preferably, the reaction atmosphere is at least one of hydrogen, an inert gas, nitrogen, and air. More preferably, in step (2), the reaction atmosphere is a reducing gas atmosphere, and even more preferably, a mixture of hydrogen and an inert gas / nitrogen. During the heat treatment, the sulfur-containing compound decomposes to generate a sulfur source, which reacts with the palladium precursor to form palladium sulfide, and simultaneously forms Pd under the action of the reducing atmosphere. x S active phase.

[0013] Preferably, the Pd precursor is at least one of palladium sulfate, palladium chloride, palladium nitrate, palladium acetate, and palladium acetylacetonate.

[0014] Preferably, the sulfur source is at least one of sodium sulfide, ammonium sulfide, methanethiol, thiourea, and thioacetamide.

[0015] Preferably, in step (1), the soaking time is 1~24 h;

[0016] And / or, in step (1), the drying temperature is 50~120 ℃ and the drying time is 6~24 h;

[0017] And / or, in step (1), the molar ratio of sulfur to palladium is 0.2 to 1.0;

[0018] And / or, in step (1), the volume ratio of the mixed solution to the alumina support is 1-2:1-2.

[0019] Preferably, in step (2), the heat treatment specifically includes: heating to T at a rate of 2-15 ℃ / min, where T is 300~700 ℃, and holding T for 1~8 h.

[0020] More preferably, in step (1), the molar ratio of sulfur to palladium is 0.5.

[0021] Preferably, the alumina-supported Pd x In S catalyst, Pd x The loading of S particles is 0.1 to 1% of the mass of the alumina carrier.

[0022] The second aspect of this invention provides an alumina-supported Pd prepared by the preparation method described above. x S catalyst.

[0023] The third aspect of the present invention provides the above-described alumina-supported Pd x Application of S catalyst in the hydrogenation catalysis of anthraquinone.

[0024] Preferably, the conditions for the anthraquinone hydrogenation catalytic reaction are: a hydrogen gas flow rate of 10~5000 mL·min. -1 The reaction temperature is 25~80 ℃; the reaction pressure is 0.1~2.0 MPa.

[0025] Compared with existing technologies, the preparation method described above and the resulting alumina-supported Pd are superior. x S catalysts have the following advantages:

[0026] (1) This invention combines impregnation and reduction methods to prepare alumina-supported Pd x S catalyst has a simple preparation method, is easy to operate, has a short production cycle, can avoid the generation of highly toxic hydrogen sulfide gas, and is easy to scale up.

[0027] (2) The alumina-supported Pd prepared by the present invention x S catalysts have the advantages of high catalytic activity, good stability and low cost. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] Example 1

[0030] An alumina-supported Pd for anthraquinone hydrogenation x The preparation method of S catalyst includes the following steps:

[0031] (1) According to the final alumina-supported Pd x Based on a Pd content of 0.1 wt% in the S catalyst, a certain amount of palladium nitrate was weighed and dissolved in deionized water. Sodium sulfide was added at a sulfur / Pd molar ratio of 0.8 and stirred thoroughly to dissolve, thus preparing a mixed solution containing a Pd precursor and a sulfur source. Alumina support was added to the mixed solution at a volume ratio of 1:1 and impregnated for 12 h. The solution was then filtered and vacuum dried at 60 °C for 12 h to obtain the catalyst precursor.

[0032] (2) The catalyst precursor was placed in a quartz tube, placed in a tube furnace, and 5% H2 / Ar mixed gas was introduced. The temperature was increased to 400 °C at a rate of 5 °C / min and held for 2 h. After the temperature inside the furnace naturally dropped to room temperature, the sample was taken out to obtain alumina-supported Pd. x S catalyst (Pd content 0.1 wt%).

[0033] Example 2

[0034] An alumina-supported Pd for anthraquinone hydrogenation x The preparation method of S catalyst includes the following steps:

[0035] (1) According to the final alumina-supported Pd x Based on a Pd content of 0.3 wt% in the S catalyst, a certain amount of palladium sulfate was weighed and dissolved in deionized water. Thioacetamide was added at a sulfur / Pd molar ratio of 1.0 and stirred thoroughly to dissolve, thus preparing a mixed solution containing a Pd precursor and a sulfur source. Alumina support was added to the mixed solution at a volume ratio of 1:1 and impregnated for 10 h. The solution was then filtered and vacuum dried at 80 °C for 12 h to obtain the catalyst precursor.

[0036] (2) The catalyst precursor was placed in a quartz tube, placed in a tube furnace, and 5% H2 / Ar mixed gas was introduced. The temperature was increased to 500 °C at a rate of 5 °C / min and held for 2 h. After the temperature inside the furnace naturally dropped to room temperature, the sample was taken out to obtain alumina-supported Pd. x S catalyst (Pd content 0.3wt%).

[0037] Example 3

[0038] An alumina-supported Pd for anthraquinone hydrogenation x The preparation method of S catalyst includes the following steps:

[0039] (1) According to the final alumina-supported Pd x Assuming a Pd content of 0.5 wt% in the S catalyst, a certain amount of palladium acetylacetonate was weighed and dissolved in deionized water. Ammonium sulfide was added at a sulfur / Pd molar ratio of 0.3 and stirred thoroughly to dissolve, thus preparing a mixed solution containing a Pd precursor and a sulfur source. Alumina support was added to the mixed solution at a volume ratio of 1:1 and impregnated for 12 h. After filtration, the solution was vacuum dried at 60 °C for 12 h to obtain the catalyst precursor.

[0040] (2) The catalyst precursor was placed in a quartz tube, placed in a tube furnace, and 10% H2 / N2 mixed gas was introduced. The temperature was increased to 300 °C at a rate of 5 °C / min and held for 4 h. After the temperature inside the furnace naturally dropped to room temperature, the sample was taken out to obtain alumina-supported Pd. x S catalyst (Pd content 0.5wt%).

[0041] Example 4

[0042] An alumina-supported Pd for anthraquinone hydrogenation x The preparation method of S catalyst includes the following steps:

[0043] (1) According to the final alumina-supported Pd x Based on a Pd content of 1 wt% in the S catalyst, a certain amount of palladium acetate was weighed and dissolved in deionized water. Methanethiol was added at a sulfur / Pd molar ratio of 0.5 and stirred thoroughly to dissolve, thus preparing a mixed solution containing a Pd precursor and a sulfur source. Alumina support was added to the mixed solution at a volume ratio of 1:1 and impregnated for 24 h. After filtration, the solution was vacuum dried at 100 °C for 24 h to obtain the catalyst precursor.

[0044] (2) The catalyst precursor was placed in a quartz tube, placed in a tube furnace, and 15% H2 / Ar mixed gas was introduced. The temperature was increased to 400 °C at a rate of 3 °C / min and held for 2 h. After the temperature inside the furnace naturally dropped to room temperature, the sample was taken out to obtain alumina-supported Pd.x S catalyst (Pd content 1wt%).

[0045] Comparative Example 1

[0046] A method for preparing an anthraquinone hydrogenation catalyst includes the following steps:

[0047] (1) Based on the Pd content of 0.3 wt% in the final catalyst, a certain amount of palladium nitrate was weighed and dissolved in deionized water. The solution containing Pd precursor was prepared by stirring thoroughly. The alumina support was added to the solution containing Pd precursor, and the volume ratio of the alumina support to the solution containing Pd precursor was 1:1. The solution was impregnated for 12 h. The solution was filtered and dried under vacuum at 80 °C for 12 h to obtain the catalyst precursor.

[0048] (2) The catalyst precursor was placed in a quartz tube, placed in a tube furnace and 5% H2 / Ar mixed gas was introduced. The temperature was increased to 500 °C at a rate of 5 °C / min and held for 2 h. After the temperature in the furnace naturally dropped to room temperature, the sample was taken out to obtain Pd / Al2O3 catalyst (Pd content 0.3wt%).

[0049] The reaction performance of the prepared catalyst was evaluated in an anthraquinone hydrogenation unit. The reaction was carried out in a hydrogen atmosphere at a temperature of 60 °C and a pressure of 1 MPa. The hydrogenation efficiency of the catalyst was measured, and the results are shown in Table 1.

[0050] Table 1. Hydrogenation efficiency results of catalysts prepared in Examples 1-4 and Comparative Example 1

[0051]

[0052] Table 1 shows that, in Examples 1-4 of this invention, Pd prepared by mixing alumina as a carrier with a sulfur source... x The S catalyst exhibits significantly enhanced catalytic performance in the anthraquinone hydrogenation reaction, with a hydrogenation efficiency reaching 8.3-11.7 g·L⁻¹. -1 In Example 2, thioacetamide was used as an organic sulfur source. During heat treatment, thioacetamide slowly decomposes and releases active sulfur species, enabling in-situ sulfidation of Pd species and promoting Pd... x The formation of the S phase enhances the interaction between Pd and the support, which is beneficial to improving Pd performance. x The dispersion and loading stability of S on the high specific surface area alumina surface result in more effective active sites being exposed on the catalyst surface, thereby significantly improving the hydrogenation efficiency of anthraquinone. The hydrogenation efficiency of Example 2 is even better.

[0053] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An alumina-supported Pd for anthraquinone hydrogenation x The method for preparing the S catalyst is characterized by: Includes the following steps: (1) Prepare a mixed solution containing Pd precursor and sulfur source, add alumina support to the mixed solution, impregnate and dry to obtain catalyst precursor; (2) The catalyst precursor is heat-treated in a reaction atmosphere to obtain the alumina-supported Pd. x S catalyst.

2. The alumina-supported Pd for anthraquinone hydrogenation according to claim 1 x The method for preparing S catalyst is characterized by: The reaction atmosphere uses at least one of hydrogen, inert gas, nitrogen, and air.

3. The alumina-supported Pd for anthraquinone hydrogenation according to claim 1 x The method for preparing S catalyst is characterized by: The Pd precursor is at least one of palladium sulfate, palladium chloride, palladium nitrate, palladium acetate, and palladium acetylacetone.

4. The alumina-supported Pd for anthraquinone hydrogenation according to claim 1 x The method for preparing S catalyst is characterized by: The sulfur source is at least one of sodium sulfide, ammonium sulfide, methanethiol, thiourea, and thioacetamide.

5. The alumina-supported Pd for anthraquinone hydrogenation according to claim 1 x The method for preparing S catalyst is characterized by: In step (1), the soaking time is 1~24 h; And / or, in step (1), the drying temperature is 50~120 ℃ and the drying time is 6~24 h; And / or, in step (1), the molar ratio of sulfur to palladium is 0.2 to 1.0; And / or, in step (1), the volume ratio of the mixed solution to the alumina support is 1-2:1-2.

6. The alumina-supported Pd for anthraquinone hydrogenation according to claim 1 x The method for preparing S catalyst is characterized by: In step (2), the heat treatment specifically includes: heating to T at a rate of 2-15 ℃ / min, where T is 300~700 ℃, and holding T for 1~8 h.

7. The alumina-supported Pd for anthraquinone hydrogenation according to claim 1 x The method for preparing S catalyst is characterized by: The alumina-supported Pd x In S catalyst, Pd x The loading of S particles is 0.1 to 1% of the mass of the alumina carrier.

8. Alumina-supported Pd prepared by the preparation method according to any one of claims 1 to 7 x S catalyst.

9. The alumina-supported Pd according to claim 8 x Application of S catalyst in the hydrogenation catalysis of anthraquinone.

10. The application according to claim 9, characterized in that: The conditions for the anthraquinone hydrogenation catalytic reaction are: a hydrogen gas flow rate of 10~5000 mL·min. -1 The reaction temperature is 25~80℃; the reaction pressure is 0.1~2.0 MPa.

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