A method for improving the hydrogenation selectivity of anthraquinone in the preparation of hydrogen peroxide by a fluidized bed

Abstract

The present invention relates to the field of hydrogen peroxide preparation, and discloses a method for improving the hydrogenation selectivity of anthraquinone in the preparation of hydrogen peroxide by a fluidized bed. In the method of the present invention, a three-component mixed gas of hydrogen, nitrogen, and ammonia is introduced into the anthraquinone hydrogenation reaction system of the fluidized bed hydrogenation reactor in a volume ratio of 60-95:10-40:0.01-1. After being fully mixed with the catalyst and the working solution, a hydrogenation reaction occurs, which can significantly reduce the formation of tetrahydroanthraquinone and anthraquinone degradation products during the anthraquinone hydrogenation process, and greatly improve the selectivity of anthraquinone hydrogenation. The method for improving the hydrogenation selectivity of anthraquinone in the present invention is suitable for the hydrogenation reactions of various anthraquinones.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen peroxide preparation, and particularly to a method for improving the hydrogenation selectivity of anthraquinone in the preparation of hydrogen peroxide by a fluidized bed. Background Art

[0002] Hydrogen peroxide is widely used in many fields such as papermaking, textile, chemical industry, environmental protection, and electronic component manufacturing. Currently, the industrial method for producing hydrogen peroxide is the anthraquinone method. In this method, alkyl anthraquinone dissolved in an organic solvent is used as a carrier for cyclic hydrogenation and oxidation. Through a series of processes such as hydrogenation, oxidation, extraction, and post-treatment, hydrogen peroxide with a certain concentration is obtained. Among them, anthraquinone plays the role of a working carrier. During the hydrogenation process, it is reduced to hydroanthraquinone, and hydroanthraquinone is oxidized to anthraquinone and hydrogen peroxide during the oxidation process.

[0003] Anthraquinone hydrogenation is a key step in the preparation of hydrogen peroxide by the anthraquinone method, directly affecting the production scale and efficiency of the device. According to the different hydrogenation methods, it is divided into two types: fixed bed and fluidized bed. Among them, the fixed bed process is the preferred technology for small and medium-sized hydrogen peroxide devices in China. It has the advantages of relatively mature technology, simple operation, easy separation of the catalyst, and low investment. However, the fixed bed hydrogenation reactor has problems such as local overheating and uneven flow of the working fluid, resulting in uneven reactions, more side reactions, and low hydrogenation efficiency. The fluidized bed process achieves a higher three-phase contact area by making the gas-liquid-solid three-phase mix evenly, and has the advantages of uniform mass transfer and heat transfer, relatively fewer side reactions, easy scale-up, and low consumption.

[0004] During the hydrogenation process, in addition to generating hydroanthraquinone, the benzene ring of anthraquinone will also be hydrogenated to form tetrahydroanthraquinone. Tetrahydroanthraquinone can also be oxidized to form hydrogen peroxide. Therefore, tetrahydroanthraquinone is considered a type of effective anthraquinone. However, since the solubility of tetrahydroanthraquinone in the working fluid is lower than that of anthraquinone, and the oxidation rate of tetrahydroanthraquinone is much slower than that of hydroanthraquinone, too high a content of tetrahydroanthraquinone will cause the precipitation of anthraquinone solids and incomplete oxidation, affecting the stable operation of the device and resulting in a reduction in output. Therefore, the content of tetrahydroanthraquinone in the working fluid cannot be too high. In addition, many side reactions will occur during the hydrogenation and oxidation of anthraquinone, generating many by-products, collectively referred to as anthraquinone degradation products. The generation of anthraquinone degradation products will cause changes in the physical and chemical properties of the working fluid, directly increasing the consumption of anthraquinone. Therefore, the content of anthraquinone degradation products in the working fluid cannot be too high.

[0005] In actual production, it is necessary to control the content of tetrahydroanthraquinone and anthraquinone degradation products in the working fluid not to be too high. The conventional method for improving the hydrogenation selectivity of anthraquinone is to introduce an additive into the hydrogenation catalyst to make the selectivity for generating hydroanthraquinone higher. However, during long-term use, there is a problem that the additive gradually loses, resulting in an irreversible decrease in the selectivity of the catalyst.

[0006] In the prior art, a Chinese patent with the application publication number CN111071994A discloses a fluidized hydrogenation process for preparing hydrogen peroxide by the anthraquinone method. By adopting the fluidized bed process, the hydrogenation depth can be controlled and the occurrence of side reactions can be reduced. However, in this process, high-concentration hydrogen needs to be prepared, and the process has little controllability. Moreover, this patent only discloses that the hydrogenation efficiency of the hydrogenation reaction of pentyl anthraquinone can reach up to 15 g / L at most. However, in the hydrogenation reaction of anthraquinone, the substituents of anthraquinone will affect the hydrogenation reaction. The hydrogenation depth and hydrogenation efficiency of this process in the hydrogenation reactions of other anthraquinones cannot be guaranteed, especially for the ethyl anthraquinone system that is most used industrially but prone to side reactions.

[0007] Therefore, there is still a need for a new hydrogenation process for anthraquinone to improve the hydrogenation depth and hydrogenation selectivity in the hydrogenation reactions of anthraquinones with different substituent types, meeting the needs of people's process production. Summary of the Invention

[0008] To solve the above technical problems, the present invention provides a method for improving the hydrogenation selectivity of anthraquinone in the preparation of hydrogen peroxide by a fluidized bed. The method of the present invention greatly improves the hydrogenation selectivity of anthraquinone by introducing a three-component mixed gas of hydrogen, nitrogen, and ammonia in the fluidized bed anthraquinone hydrogenation reaction, and is suitable for the hydrogenation reactions of various anthraquinones.

[0009] The specific technical solution of the present invention is as follows:

[0010] A method for improving the hydrogenation selectivity of anthraquinone in the preparation of hydrogen peroxide by a fluidized bed, comprising:

[0011] In the anthraquinone hydrogenation reaction system of a fluidized bed hydrogenation reactor, a three-component mixed gas of hydrogen, nitrogen, and ammonia is introduced according to a volume ratio of 60-95:10-40:0.01-1. After being fully mixed with the catalyst and the working solution, a hydrogenation reaction occurs.

[0012] The present invention reduces the formation of tetrahydroanthraquinone and anthraquinone degradation products in an atmosphere of a gas mixture of hydrogen, nitrogen, and ammonia mixed according to a volume ratio of 60-95:10-40:0.01-1, and improves the hydrogenation selectivity of anthraquinone. Compared with the fluidized bed process for preparing hydrogen peroxide by only introducing hydrogen or a two-component mixed gas of hydrogen and nitrogen, the formation of tetrahydroanthraquinone and anthraquinone degradation products during the anthraquinone hydrogenation process can be significantly reduced. Compared with the conventional method of introducing additives into the catalyst to improve the hydrogenation selectivity of anthraquinone, in the method for improving the hydrogenation selectivity of anthraquinone of the present invention, the component content ratio of the hydrogen, nitrogen, and ammonia mixed gas is easy to adjust and control, ensuring the stability of the mixed gas content ratio, and avoiding the problem of the decrease in hydrogenation selectivity caused by the gradual loss of additives during long-term use in the process of improving the hydrogenation selectivity of anthraquinone by introducing additives into the hydrogenation catalyst.

[0013] When the volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is in the range of 60 - 95:10 - 40:0.01 - 1, it has a good effect of improving the selectivity of anthraquinone hydrogenation.

[0014] Specifically, the method of introducing the mixed gas of hydrogen, nitrogen, and ammonia in a volume ratio of 60 - 95:10 - 40:0.01 - 1 is preferably that the hydrogen-nitrogen mixed gas is first preliminarily mixed with ammonia to form a preliminary three-component mixed gas. After the tail gas from the reaction is separated from the liquid by a gas-liquid separator, it is compressed again by a recycle hydrogen compressor, mixed with the preliminary three-component mixed gas, and then enters the hydrogenation reactor again to realize the reuse of hydrogen and ammonia in the tail gas. Specifically, the content ratio control of the three-component mixed gas is achieved by setting an ammonia flow regulating valve and an ammonia mass flowmeter on the ammonia inlet pipeline, and setting an ammonia analyzer before the three-component mixed gas enters the hydrogenation tower to control and adjust the ammonia content in the mixed gas.

[0015] Preferably, the top pressure of the anthraquinone hydrogenation reaction system is 0.04 - 0.3 MPaG.

[0016] Specifically, the catalyst for the anthraquinone hydrogenation reaction system is a palladium supported on a carrier catalyst, and the palladium content of the palladium supported on a carrier catalyst is 1.0 - 4.0 wt%. The carrier is selected from alumina carriers, silica carriers, and silica-alumina composite carriers.

[0017] Specifically, the working fluid of the anthraquinone hydrogenation reaction system is formed by dissolving an anthraquinone compound in a solvent. The anthraquinone compound is one or more of 2-ethylanthraquinone, 2-butylanthraquinone, and 2-pentylanthraquinone.

[0018] Specifically, the solvent is a mixture of a non-polar solvent and a polar solvent, and the volume ratio of the non-polar solvent to the polar solvent is 1 - 8:1.

[0019] Preferably, the non-polar solvent is a heavy aromatic hydrocarbon.

[0020] Preferably, the polar solvent is one or more of trioctyl phosphate, 2-methylcyclohexyl acetate, tetrabutylurea, and diisobutyl carbinol.

[0021] Specifically, the mass ratio of the palladium supported on a carrier catalyst to the working fluid is preferably 0.5 - 6:100.

[0022] Specifically, the temperature of the anthraquinone hydrogenation reaction system is preferably 40 - 80 °C.

[0023] Compared with the prior art, the present invention has the following technical effects:

[0024] (1) By introducing a three-component mixture of hydrogen, nitrogen, and ammonia into the reaction system, the method of the present invention can significantly reduce the formation of tetrahydroanthraquinone and anthraquinone degradation products during the anthraquinone hydrogenation process, greatly improving the selectivity of anthraquinone hydrogenation.

[0025] (2) In the process of the method of the present invention, by regulating the introduction of the mixed gas, it is easier to adjust and control compared to controlling other process conditions in the process.

[0026] (3) The method for improving the selectivity of anthraquinone hydrogenation of the present invention is suitable for the hydrogenation reactions of various anthraquinones. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic process flow diagram of the present invention.

[0028] Reference numerals: hydrogen-nitrogen mixed gas inlet pipe 1, ammonia inlet pipe 2, tail gas reflux pipe 3, gas-liquid separator 4, hydrogen compressor 5, ammonia flow regulating valve 6, ammonia mass flowmeter 7, ammonia analyzer 8, hydrogenation reactor 9. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be further described below in conjunction with embodiments.

[0030] General Embodiment

[0031] In the anthraquinone hydrogenation reaction system, a three-component mixed gas of hydrogen, nitrogen, and ammonia is introduced in a volume ratio of 60 - 95:10 - 40:0.01 - 1. After being fully mixed with the catalyst and the working liquid, a hydrogenation reaction occurs. As Figure 1 shown, the hydrogen-nitrogen mixed gas first passes through the hydrogen-nitrogen mixed gas inlet pipe 1 and is preliminarily mixed with the ammonia introduced from the ammonia inlet pipe 2 to form a preliminary three-component mixed gas. After the tail gas from the reaction in the hydrogenation reactor 9 passes through the tail gas reflux pipe 3 and is separated from the liquid by the gas-liquid separator 4, it is compressed again by the circulating hydrogen compressor 5, mixed with the preliminary three-component mixed gas, and then enters the hydrogenation reactor again to realize the reuse of hydrogen and ammonia in the tail gas. Specifically, the control of the content ratio of the three-component mixed gas is achieved by setting an ammonia flow regulating valve 6 and an ammonia mass flowmeter 7 on the ammonia inlet pipe of 2, and by setting an ammonia analyzer 8 before the three-component mixed gas enters the hydrogenation tower to control and adjust the ammonia content in the mixed gas.

[0032] The anthraquinone hydrogenation reaction system further includes: a fluidized bed hydrogenation reactor with a top pressure of 0.04 - 0.3 MPaG and a temperature of 40 - 80 °C; the mass ratio of the catalyst to the working fluid is 0.5 - 6:100; the catalyst is a palladium supported on a carrier catalyst, and the palladium content of the palladium supported on a carrier catalyst is 1.0 - 4.0 wt%, and the carrier is selected from an alumina carrier, a silica carrier, and a silica-alumina composite carrier; the working fluid is formed by dissolving an anthraquinone compound in a solvent, the anthraquinone compound is one or more of 2-ethylanthraquinone, 2-butylanthraquinone, and 2-pentylanthraquinone, and the solvent is a mixture of a non-polar solvent and a polar solvent in a volume ratio of 1 - 8:1, the non-polar solvent is a heavy aromatic hydrocarbon, and the polar solvent is one or more of trioctyl phosphate, 2-methylcyclohexyl acetate, tetrabutylurea, and diisobutyl methanol.

[0033] Example 1

[0034] In the fluidized bed hydrogenation reactor, a heavy aromatic hydrocarbon, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents, and 2-ethylanthraquinone is dissolved in the solvent to form a working fluid with a 2-ethylanthraquinone concentration of 160 g / L. The catalyst used is a palladium supported on activated alumina catalyst with an average particle size of 50 microns and a palladium content of 2 wt%, and the mass ratio of the catalyst to the working fluid is 0.6:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working fluid entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.6, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0035] Example 2

[0036] In the fluidized bed hydrogenation reactor, a heavy aromatic hydrocarbon, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents, and 2-ethylanthraquinone is dissolved in the solvent to form a working fluid with a 2-ethylanthraquinone concentration of 160 g / L. The catalyst used is a palladium supported on activated alumina catalyst with an average particle size of 50 microns and a palladium content of 2 wt%, and the mass ratio of the catalyst to the working fluid is 0.6:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working fluid entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.01, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0037] Example 3

[0038] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-Ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is a palladium catalyst supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 0.6:100. A three-component mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.3, the bed reaction temperature is 55°C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0039] Example 4

[0040] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-Ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is a palladium catalyst supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 0.6:100. A three-component mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:1, the bed reaction temperature is 55°C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0041] Example 5

[0042] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and tetrabutylurea with a volume ratio of 65:10:25 are used as solvents. 2-ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is palladium supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 4 wt%, and the mass ratio of the catalyst to the working solution is 0.6:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.5, the bed reaction temperature is 40 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0043] Example 6

[0044] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and tetrabutylurea with a volume ratio of 65:10:25 are used as solvents. 2-butylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-butylanthraquinone is 220 g / L. The catalyst used is palladium supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 1.1:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:10:0.5, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0045] Example 7

[0046] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and tetrabutylurea with a volume ratio of 65:10:25 are used as solvents. 2-Pentylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-pentylanthraquinone is 300 g / L. The catalyst used is palladium supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 1.6:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, ethyl anthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.5, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-pentylanthraquinone, and the content of pentylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0047] Example 8

[0048] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 64:5:3 are used as solvents. 2-Ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is palladium supported on silica. The average particle size of the catalyst is 80 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 3:50. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.5, the bed reaction temperature is 80 °C, the residence time is 30 minutes, and the top pressure is 0.04 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0049] Example 9

[0050] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 35:20:15 are used as solvents. 2-Ethylanthraquinone is dissolved in the solvents to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is a palladium catalyst supported on silica. The average particle size of the catalyst is 80 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 0.8:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 95:40:1, the bed reaction temperature is 55°C, the residence time is 30 minutes, and the top pressure is 0.3 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0051] Example 10

[0052] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-Ethylanthraquinone is dissolved in the solvents to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is a palladium catalyst supported on silica. The average particle size of the catalyst is 80 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 0.8:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 60:30:0.1, the bed reaction temperature is 55°C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0053] Example 11

[0054] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and tetrabutylurea with a volume ratio of 65:10:25 are used as solvents. 2-ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 220 g / L. The catalyst used is palladium supported on silica, with an average particle size of the catalyst being 80 microns, a palladium content of 1 wt%, and a mass ratio of the catalyst to the working solution of 0.8:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.5, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction is completed, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0055] Example 12

[0056] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and tetrabutylurea with a volume ratio of 65:10:25 are used as solvents. 2-pentylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-pentylanthraquinone is 300 g / L. The catalyst used is palladium supported on activated alumina, with an average particle size of the catalyst being 50 microns, a palladium content of 2 wt%, and a mass ratio of the catalyst to the working solution of 1.6:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.6, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction is completed, the hydrogenation efficiency, the content of tetrahydro-2-pentylanthraquinone, and the content of pentylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0057] Comparative Example 1 (The main difference from Example 1 is that ammonia is not introduced into the mixed gas)

[0058] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-Ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is a palladium catalyst supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 0.6:100. A binary mixture of hydrogen and nitrogen gas is dispersed through a gas distributor and then mixed with the working solution that enters from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen to nitrogen in the mixed gas is controlled to be 70:30, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0059] Comparative Example 2 (the main difference from Example 1 is that the volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is 70:30:0.001)

[0060] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-Ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is a palladium catalyst supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 0.6:100. A ternary mixture of hydrogen, nitrogen, and ammonia gas is dispersed through a gas distributor and then mixed with the working solution that enters from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.001, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0061] Comparative Example 3 (the main difference from Example 1 is that the volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is 70:30:2)

[0062] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst used is a palladium catalyst supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of the catalyst to the working solution is 0.6:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:2, the bed reaction temperature is 55°C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0063] Comparative Example 4 (The main difference from Example 1 is that a mixed gas of hydrogen and nitrogen is introduced in a volume ratio of 70:30, and a trace amount of ammonia water is added to the working solution)

[0064] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. Ammonia water with a concentration of 25 wt% and the catalyst are added to the working solution. The catalyst used is a palladium catalyst supported on activated alumina. The average particle size of the catalyst is 50 microns, the palladium content is 2 wt%, and the mass ratio of ammonia water, the catalyst to the working solution is 0.005:0.6:100. A mixed gas of hydrogen and nitrogen is dispersed through a gas distributor and then mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen and nitrogen in the mixed gas is controlled to be 70:30, the bed reaction temperature is 55°C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0065] Comparative Example 5 (The main difference from Example 1 is that a mixed gas of hydrogen and nitrogen is introduced in a volume ratio of 70:30, and a trace amount of sodium hydroxide is added to the working solution)

[0066] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. A catalyst and sodium hydroxide are added to the working solution. The catalyst is palladium supported on activated alumina, with an average particle size of 50 microns and a palladium content of 2 wt%. The mass ratio of sodium hydroxide, catalyst, and working solution is 0.001:0.6:100. A mixed gas of hydrogen, nitrogen, and three components is dispersed through a gas distributor and mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen to nitrogen in the mixed gas is controlled to be 70:30, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0067] Comparative Example 6 (The main difference from Example 1 is that the catalyst used is platinum)

[0068] In a fluidized bed hydrogenation reactor, heavy aromatic hydrocarbons, trioctyl phosphate, and 2-methylcyclohexyl acetate with a volume ratio of 65:20:15 are used as solvents. 2-ethylanthraquinone is dissolved in the solvent to form a working solution, and the concentration of 2-ethylanthraquinone is 160 g / L. The catalyst is platinum supported on activated alumina, with an average particle size of 50 microns and a platinum content of 2 wt%. The mass ratio of the catalyst to the working solution is 0.6:100. A mixed gas of hydrogen, nitrogen, and ammonia is dispersed through a gas distributor and mixed with the working solution entering from the bottom of the reactor. Under the action of the catalyst in the reactor, 2-ethylanthraquinone undergoes a hydrogenation reaction. The volume ratio of hydrogen, nitrogen, and ammonia in the mixed gas is controlled to be 70:30:0.6, the bed reaction temperature is 55 °C, the residence time is 30 minutes, and the top pressure is 0.1 MPaG. After the reaction, the hydrogenation efficiency, the content of tetrahydro-2-ethylanthraquinone, and the content of ethylanthraquinone degradation products are measured, and the hydrogenation selectivity is calculated.

[0069] Data measurement

[0070] The results of the hydrogenation efficiency, the content of tetrahydroanthraquinone, the content of anthraquinone degradation products, and the hydrogenation selectivity of Examples 1 to 12 and Comparative Examples 1 to 6 are shown in Table 1. Among them, the test method for hydrogenation efficiency is as follows: Using the chemical titration method, take 5 ml of the hydrogenated solution, completely oxidize it, extract it with water, and then titrate the amount of hydrogen peroxide in the aqueous phase obtained by extraction with potassium permanganate. Through the quantitative chemical reaction of potassium permanganate and hydrogen peroxide, the content of hydrogen peroxide in the hydrogenated solution per unit volume can be obtained, which is the hydrogenation efficiency. The determination methods for the contents of tetrahydroanthraquinone and anthraquinone degradation products are as follows: Take 5 ml of the hydrogenated solution, oxidize it by passing air, then extract and remove hydrogen peroxide in the organic phase with water, and analyze the contents of tetrahydroanthraquinone and anthraquinone degradation products in the organic phase by chromatography. The hydrogenation selectivity represents the selectivity for generating the target product hydroanthraquinone.

[0071] Table 1

[0072]

[0073] Data analysis:

[0074] (1) From the data results of the hydrogenation efficiency, the content of tetrahydroanthraquinone, the content of anthraquinone degradation products, and the hydrogenation selectivity of Examples 1 to 12 in Table 1, it can be seen that in the anthraquinone hydrogenation reaction system of the fluidized bed hydrogenation reactor, when a three-component mixed gas of hydrogen, nitrogen, and ammonia is introduced in a volume ratio of 70:29:0.01 to 1, the generation of tetrahydroanthraquinone and anthraquinone degradation products during the anthraquinone hydrogenation process can be significantly reduced, the selectivity of anthraquinone hydrogenation can be greatly improved, and at the same time, the hydrogenation efficiency is high.

[0075] (2) Compared with Example 1, in Comparative Example 1, ammonia is not introduced, the content of tetrahydroanthraquinone and the content of anthraquinone degradation products increase, and the hydrogenation efficiency and hydrogenation selectivity become lower, indicating that the introduction of ammonia is beneficial to improving the hydrogenation efficiency and hydrogenation selectivity.

[0076] (2) Compared with Example 1, in Comparative Example 2, the volume ratio of hydrogen, nitrogen, and ammonia in the introduced mixed gas is 70:30:0.001, the ammonia content is too low, the content of tetrahydroanthraquinone and the content of anthraquinone degradation products increase, and the hydrogenation efficiency and hydrogenation selectivity become lower, indicating that the introduction ratio of ammonia should be within a certain content range to improve the hydrogenation efficiency and hydrogenation selectivity.

[0077] (3) Compared with Example 1, in Comparative Example 3, the volume ratio of hydrogen, nitrogen, and ammonia in the introduced mixed gas is 70:30:2, the ammonia content is too high, the content of tetrahydroanthraquinone and the content of anthraquinone degradation products increase, and the hydrogenation efficiency and hydrogenation selectivity become lower. Combining the data of Comparative Example 1 and Comparative Example 2, it shows that the introduction ratio of ammonia and the volume ratio of hydrogen, nitrogen, and ammonia should be within a suitable range to effectively improve the hydrogenation efficiency and hydrogenation selectivity.

[0078] (4) Compared with Example 1, in Comparative Example 4, ammonia gas was not introduced, and the microenvironment of the hydrogenation reaction was adjusted by adding ammonia water to the working fluid. As a result, the content of tetrahydroanthraquinone and the content of anthraquinone degradation products increased significantly, and the hydrogenation efficiency and hydrogenation selectivity became lower. This shows that directly introducing ammonia water cannot effectively improve the hydrogenation efficiency and hydrogenation selectivity. Further analysis reveals that there is also a problem of controlling the water volume in the system when directly introducing ammonia water. Directly introducing ammonia water cannot achieve the improvement effect of ammonia molecules on the hydrogenation efficiency and hydrogenation selectivity, and it will also increase the difficulty of the entire hydrogen peroxide preparation process.

[0079] (5) Compared with Example 1, in Comparative Example 5, ammonia gas was not introduced, and the microenvironment of the hydrogenation reaction was adjusted by adding sodium hydroxide to the working fluid. As a result, the content of tetrahydroanthraquinone and the content of anthraquinone degradation products increased significantly, and the hydrogenation efficiency and hydrogenation selectivity became lower. This shows that adding sodium hydroxide cannot improve the hydrogenation efficiency and hydrogenation selectivity. Further analysis reveals that the addition of strongly alkaline sodium hydroxide may also cause the accelerated loss of palladium. Directly adding sodium hydroxide to adjust the initial reaction environment cannot achieve the improvement effect on the hydrogenation efficiency and hydrogenation selectivity, and there is also a possibility of accelerated palladium loss resulting in a decrease in hydrogenation selectivity.

[0080] (6) Compared with Example 1, in Comparative Example 6, the catalyst used was platinum. The content of tetrahydroanthraquinone and the content of anthraquinone degradation products increased, and the hydrogenation efficiency and hydrogenation selectivity became lower. This shows that when a mixed gas of hydrogen, nitrogen, and ammonia is introduced into the anthraquinone hydrogenation reaction system, there may be an influence process of the catalyst on improving the hydrogenation selectivity.

[0081] In the present invention, the raw materials and equipment used, unless otherwise specified, are all common raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0082] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for improving the hydrogenation selectivity of anthraquinone in the preparation of hydrogen peroxide by a fluidized bed, characterized in that, In the fluidized bed anthraquinone hydrogenation reaction system, a hydrogenation reaction occurs by introducing a mixed gas of hydrogen, nitrogen, and ammonia. The volume ratio of hydrogen, nitrogen, and ammonia is 60-95:10-40:0.01-1. The working fluid solvent in the fluidized bed anthraquinone hydrogenation reaction system includes a non-polar solvent and a polar solvent. The non-polar solvent is heavy aromatic hydrocarbon, and the polar solvent is a variety of trioctyl phosphate, 2-methylcyclohexyl acetate, tetrabutylurea, and diisobutyl methanol. The catalyst is a palladium catalyst supported on a carrier, and the carrier includes one of an alumina carrier, a silica carrier, and a silica-alumina composite carrier.

2. The method according to claim 1, characterized in that The top pressure of the anthraquinone hydrogenation reaction system is 0.04-0.3 MPaG.

3. The method according to claim 1, characterized in that, The palladium content of the palladium catalyst supported on the carrier is 1.0-4.0 wt%.

4. The method according to claim 1, characterized in that, The anthraquinone hydrogenation reaction system also includes an anthraquinone compound.

5. The method according to claim 4, characterized in that, The anthraquinone compound is one or more of 2-ethylanthraquinone, 2-butylanthraquinone, and 2-pentylanthraquinone.

6. The method according to claim 1, characterized in that, The volume ratio of the non-polar solvent to the polar solvent is 1-8:

1.

7. The method according to claim 1, characterized in that, The mass ratio of the palladium catalyst supported on the carrier to the working fluid is 0.5-6:

100.

8. The method according to claim 1, wherein The temperature of the fluidized bed anthraquinone hydrogenation reaction system is 40-80 °C.

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