Preparation method of solid base catalyst, solid base catalyst and its application

Abstract

The present invention provides a method for preparing a solid base catalyst, comprising the following steps: (1) acidifying the catalyst with a certain amount of dilute hydrochloric acid solution; (2) dispersing the catalyst material after acid treatment in step (1) in an organic solvent, dropwise adding a silane coupling agent while stirring under nitrogen protection, and then dropwise adding deionized water to allow the coupling agent to combine with the catalyst material; (3) using sodium alginate to make the prepared powder catalyst into catalyst pellets. The prepared solid base catalyst is surface-modified by a silane coupling agent, introducing basic amino groups, greatly increasing the basic active sites of the carrier material, and the active components are not easily lost. The present invention provides a solid base catalyst prepared based on the above method, and the application of the solid base catalyst in the regeneration of anthraquinone degradation products.

Description

Technical Field

[0001] The present invention relates to the field of chemical industry, and more specifically, to a solid base catalyst for the regeneration of degradation products in anthraquinone working fluid and a preparation method thereof. Background Art

[0002] In recent years, solid base heterogeneous catalysts with various industrial applications have attracted wide attention due to their simple synthesis process, uniform pore size distribution, large specific surface area, and high alkalinity. Solid base catalysts include metal oxides, zeolites, supported alkali metal compounds, clay minerals, etc., and are mainly applied to reactions such as double bond isomerization, hydrogenation, amination, dehydrogenation cyclodimerization, aldol addition, nitro aldol reaction, Michael addition, etc. in organic reactions. Generally, mesoporous solid base catalysts can be divided into two categories. One is a mesoporous structure catalyst with inherent basicity in the material, such as mesoporous magnesium oxide solid base prepared by the template method; however, this method often requires expensive template agents to regulate the required pore structure. The other is to prepare a solid base catalyst by introducing a basic guest material onto a mesoporous host framework material without basicity. According to the structural properties of the host framework material, different types of guest species can be selected to prepare a series of solid base catalysts with different basic site strengths and quantities. The basic guest species include basic metal oxides (such as Na2O, K2O, etc.) which are easily soluble in water and cause the loss of active components, as well as alkaline earth metal oxides (such as MgO, CaO, etc.), various organic bases, etc.

[0003] 98% of the domestic industrial production capacity of hydrogen peroxide comes from the anthraquinone process. In this process, alkyl anthraquinone is used as a reaction intermediate. While continuously circulating to produce hydrogen peroxide in the device, other degradation products are also generated. These anthraquinone degradation products do not have the ability to produce hydrogen peroxide. The accumulation of degradation products will not only cause a decline in the quality and output of hydrogen peroxide products, but also increase the density and viscosity of the working fluid, thereby increasing the operating burden of the equipment and raising the production cost of the products. Currently, the main catalyst for the regeneration of anthraquinone degradation products used in industry is spherical activated alumina impregnated with sodium hydroxide solution, which will show a pulverization phenomenon during use, resulting in the turbidity of the working fluid. Through research by the research group, it is found that the effective anthraquinone regenerated by activated alumina is mainly tetrahydroanthraquinone, and its regeneration performance for 2-ethylanthraquinone in the working fluid is not good. Excessive tetrahydroanthraquinone will trigger the generation of more anthraquinone degradation products. Moreover, the basic components of basic alumina are easily lost, resulting in problems such as low regeneration performance and short service life. In actual production, to ensure the stable output of products, it is necessary to frequently disassemble and install the regeneration bed. The replaced regeneration catalyst will consume part of the working fluid due to adsorption, and the old alumina catalyst will also bring the problem of waste solid treatment. Therefore, developing a highly efficient, stable, and long-service-life regeneration catalyst is an urgent problem to be solved in the production of hydrogen peroxide by the anthraquinone process.

[0004] Chinese Patent CN103878021A discloses the use of alkyl aniline as a regenerated catalyst. The invention provides that when the amount of the organic base: N, N-dibutylaniline catalyst is 5 mL, the amount of the working solution is 100 mL, and the reaction temperature is 40 °C, after 24 h of the regeneration reaction, the effective anthraquinone increment range of the catalyst is 4.02 g·L -1 . After 36 h of the reaction, the remaining amount of the organic base is 96.43%, showing high stability in the reaction system of the anthraquinone working solution.

[0005] Chinese Patent CN109772464A discloses a solid base regenerant and its preparation method and application. The solid base is composed of a magnesium, zirconium, aluminum composite oxide, an alkali metal hydroxide, and a fluorosilane compound, and then the alkali metal hydroxide and the fluorosilane compound are loaded on the magnesium, zirconium, aluminum composite oxide. This solid base has the advantages of not being prone to loss of basic sites, high mechanical strength, and good regeneration effect when used for the regeneration of anthraquinone degradation products, and the effective anthraquinone regeneration amount reaches 19.2 g / L. Summary of the Invention

[0006] Aiming at the problem that some mesoporous catalyst materials currently have no basic sites or the strength of the basic sites is relatively low, the present invention provides a modified preparation method for enhancing the basic sites of the catalyst material, which is applicable to the regeneration of degradation products in the anthraquinone working solution. The catalyst modified by the method has excellent 2-ethylanthraquinone regeneration amount in the regeneration reaction of anthraquinone degradation products.

[0007] A preparation method of a solid base catalyst, characterized in that the preparation method specifically comprises the following steps: Step A: Weigh a certain amount of catalyst material into a first beaker, add a certain amount of dilute hydrochloric acid solution with a concentration of 0.5 - 10 mol / L, stir at a rotation speed of 400 - 900 rpm, react at 20 - 80 °C for 1 - 10 h to obtain a first slurry, centrifuge and collect the first slurry, wash it until the pH is neutral to obtain a treated slurry, then transfer part of the treated slurry into an oven at 50 - 80 °C and dry it for 12 - 48 h, and grind it into powder for standby; Step B: Add the powder prepared in Step A into a second beaker, add a certain amount of organic solvent and stir at a rotation speed of 500 - 800 rpm for 0.5 - 5 h to make it fully dispersed, place the second beaker on a magnetic stirring table, then slowly drop a certain amount of modifier under a N2 atmosphere, continue to stir for 1 - 10 h, slowly drop deionized water through a peristaltic pump, and then continue to stir and react at 20 - 80 °C for 1 - 10 h to obtain a second slurry, then wash the second slurry with ethanol, centrifuge and separate to obtain a wet material, and place the wet material in an oven at 50 - 80 °C and dry it for 12 - 48 h to obtain a powder sample; Step C: Dissolve an appropriate amount of sodium alginate in deionized water to obtain a solution, add the powder sample prepared in Step B into the solution, stir evenly and then drop it into a calcium chloride solution, and form calcium alginate through ion exchange to solidify the droplets to obtain catalyst pellets, wash the catalyst pellets with deionized water, and then transfer them into an oven at 50 - 80 °C and dry them for 10 - 48 h to obtain a solid base catalyst.

[0008] Further, the solid-liquid ratio of the catalyst material to the dilute hydrochloric acid solution in Step A is 1:1 - 1:30.

[0009] Further, the organic solvent in Step B is any one of absolute ethanol, propanol, ethylene glycol, glycerol, butanol, etc., preferably absolute ethanol; the solid-liquid ratio of the dosage of the organic solvent to the dosage of the powder is 10:1 - 1:10.

[0010] Further, the solid-liquid ratio of the added modifier to the catalyst material in Step B is 0.1 - 4 mL / g.

[0011] Further, the volume ratio of the added deionized water dosage to the organic solvent in Step B is 0 - 100.

[0012] Further, the concentration of the calcium chloride solution in Step C is 0.1 - 10 wt%.

[0013] Further, the mass ratio of sodium alginate to the catalyst material in Step C is 1:1 - 1:10, and the solid-liquid ratio of the slurry is 1:1 - 1:20.

[0014] Further, the catalyst material in step A includes: attapulgite; alumina, magnesia, calcium oxide, metal oxides or a composite material of any two of them.

[0015] Further, the modifier in step B is selected from one or more of: 3-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 3-[2-(2-aminoethylamino)amino]propyl-trimethoxysilane or bis[3-(trimethoxysilyl)propyl].

[0016] The present invention also provides a solid base catalyst prepared by the preparation method of the above solid base catalyst. The specific surface area of the solid base catalyst is 100 - 800 m 2 ·g -1 , pore volume: 0.3 - 3.0 cm 3 ·g -1 , and the particle size is 1 - 10 mm.

[0017] The present invention also provides an application of the solid base catalyst. The solid base catalyst is prepared by the preparation method of the above solid base catalyst, and this catalyst is used for the regeneration of anthraquinone degradation products in the working fluid during the production of hydrogen peroxide by the anthraquinone method.

[0018] The anthraquinone regeneration test method is as follows: Weigh 3 g of the solid base and 30 ml of the working fluid and add them to a conical flask, keep them in a constant temperature oscillation in a water bath at 50 °C, and take out the working fluid after reacting for 72 hours for analysis by liquid chromatography. The chromatographic analysis conditions are: Agilent 1260 high performance liquid chromatograph, C18 chromatographic column, the wavelength of the ultraviolet detector is 245 nm, the volume ratio of methanol to water in the mobile phase is 65:35, the flow rate is 1 ml / min, and the external standard method is used for quantitative analysis.

[0019] The beneficial effects of the present invention are:

[0020] For the solid base catalyst prepared by the present invention, by adopting the modification method with a silane coupling agent, the specific surface area and the surface basicity intensity of the catalyst are improved, and tetrahydro-2-ethylanthraquinone in the anthraquinone working fluid is effectively regenerated into 2-ethylanthraquinone. The experimental results show that after 72 h of the regeneration reaction of the solid base catalyst prepared by the present invention, the regeneration amount of 2-ethylanthraquinone reaches 14.56 g / L, and it has excellent regeneration activity. Description of the Drawings

[0021] Figure 1 XRD spectrum of the sample prepared in Example 2;

[0022] Figure 2 FT-IR spectrum of the sample prepared in Example 2;

[0023] Figure 3Morphology diagram of the sample prepared in Example 2;

[0024] Figure 4 N2 adsorption - desorption isotherm diagram of the sample prepared in Example 2;

[0025] Figure 5 Pore size distribution diagram of the sample prepared in Example 2. Detailed implementation manners

[0026] To enable those skilled in the art to better understand the technical solutions of the present invention, the following provides a detailed description of a solid base catalyst and its preparation method provided by the present invention in combination with examples. The following examples are only used to illustrate the present invention and not to limit the scope of the present invention.

[0027] Example 1

[0028] Step A: Weigh 8.00 g of calcium oxide into a beaker, then add 160 mL of 0.5 mol / L dilute hydrochloric acid solution to the beaker, stir at a speed of 600 rpm, react at 50 °C for 3 h, centrifuge and collect the obtained slurry, wash it until the pH is neutral, then transfer the sample to an oven at 60 °C and dry it for 12 h, and grind it into powder for later use. It should be noted that the calcium oxide here is exemplary, and it can also be attapulgite; metal oxides such as alumina and magnesia, or a composite material of any two of them, which will not be elaborated below.

[0029] Step B: Add 6.00 g of the powder prepared in Step A into a beaker, add 150 mL of absolute ethanol, place the beaker on a magnetic stirring table and stir at a speed of 900 rpm for 3 h to fully disperse it, then slowly drop 5 mL of bis[3-(trimethoxysilyl)propyl]amine under a N2 atmosphere, continue stirring for 2 h, slowly drip 100 mL of deionized water through a peristaltic pump, after the dripping is completed, continue stirring and reacting at 60 °C for 4 h, then wash the obtained slurry with ethanol, and after centrifugal separation, place the obtained wet material in an oven at 80 °C and dry it for 24 h to obtain a powder sample.

[0030] Step C: Dissolve 1.0 g of sodium alginate in 40 mL of deionized water, add 4.0 g of the powder sample prepared in Step B, stir evenly and then drop it into a 1.5 wt% calcium chloride solution to obtain catalyst pellets, wash the pellets with deionized water, transfer the sample to an oven at 60 °C and dry it for 24 h to obtain a modified calcium oxide solid base catalyst. Specific surface area of the anthraquinone degradation product regeneration catalyst: 376.14 m 2 ·g -1 , pore volume: 0.59 cm 3 ·g -1 , regeneration amount of diethylanthraquinone: 11.78 g·L -1 (50 °C, 3 g catalyst, 50 mL working solution, react for 72 h).

[0031] Example 2

[0032] Step A: Weigh 10.00 g of attapulgite into a beaker, then add 100 mL of 1 mol / L dilute hydrochloric acid solution to the beaker, stir at a speed of 800 rpm, react at 70 °C for 4 h, centrifuge and collect the obtained slurry, wash it until the pH is neutral, then transfer the sample to an oven at 70 °C and dry it for 12 h, and grind it into powder for standby.

[0033] Step B: Add 5.00 g of the powder prepared in Step A into a beaker, add 100 mL of absolute ethanol, place the beaker on a magnetic stirring table and stir at a speed of 700 rpm for 1 h to disperse it fully, then slowly drop 10 mL of bis[3-(trimethoxysilyl)propyl]amine under a N2 atmosphere, continue to stir for 1 h, slowly drip 100 mL of deionized water through a peristaltic pump, after the dripping is completed, continue to stir and react at 50 °C for 4 h, then wash the obtained slurry with ethanol, and after centrifugal separation, place the obtained wet material in an oven at 70 °C and dry it for 12 h.

[0034] Step C: Dissolve 0.5 g of sodium alginate in 30 mL of deionized water, add 4.5 g of the powder sample prepared in Step B, stir evenly and then drop it into a 3 wt% calcium chloride solution to obtain catalyst pellets, wash the pellets with deionized water, transfer the sample to an oven at 70 °C and dry it for 12 h to obtain a modified attapulgite solid base catalyst. The specific surface area of the prepared sample is: 430.31 m 2 ·g -1 , the pore volume is: 0.91 cm 3 ·g -1 , the regeneration amount of diethylanthraquinone: 17.02 g·L -1 (50 °C, 5 g of catalyst, 50 mL of working solution, react for 72 h).

[0035] The prepared sample was tested using an X-ray diffractometer. Figure 1 is the XRD pattern of the sample in Example 2. Characteristic diffraction peaks of attapulgite appear at 2θ = 8.54°, 27.71°, 35.40°, and 60° in the figure; Figure 2 is the test spectrum of the sample by Fourier transform infrared spectrometer. The stretching vibration peak of Si-O-Si is at 1039 cm -1 , which is the characteristic absorption peak of attapulgite and the modifier. The absorption peaks at 1466 cm -1 and 2918 cm -1 correspond to the vibration peaks of alkyl C-H, indicating that the modifier has been successfully grafted onto the surface of attapulgite; Figure 3 is the scanning electron micrograph of the sample in Example 2. It can be observed that the modifier is wrapped on the surface of the attapulgite catalyst; Figure 4It is the nitrogen adsorption - desorption (BET) test diagram of the sample in Example 2, proving that the prepared modified attapulgite solid base catalyst has a mesoporous structure; Figure 5 It is the pore size distribution diagram of the sample in Example 2, and the pore size is concentrated in the range of 10 - 20 nm.

[0036] Example 3

[0037] Step A: Weigh 15.00 g of alumina into a beaker, then add 150 mL of 0.2 mol / L dilute hydrochloric acid solution to the beaker, stir at a speed of 500 rpm, react at 65 °C for 1 h, centrifuge and collect the obtained slurry, wash it until the pH is neutral, then transfer the sample to an oven at 80 °C and dry it for 12 h, and grind it into powder for standby.

[0038] Step B: Add 5.00 g of the powder prepared in Step A into a beaker, add 150 mL of absolute ethanol, place the beaker on a magnetic stirring table and stir at a speed of 900 rpm for 2 h to fully disperse it, then slowly add 15 mL of bis[3 - (trimethoxysilyl)propyl]amine under a N₂ atmosphere, continue to stir for 1 h, slowly drip 50 mL of deionized water through a peristaltic pump, after the dripping is completed, continue to stir and react at 70 °C for 4 h, then wash the obtained slurry with ethanol, after centrifugal separation, place the obtained wet material in an oven at 80 °C and dry it for 12 h.

[0039] Step C: Dissolve 1.5 g of sodium alginate in 40 mL of deionized water, add 4.5 g of the powder sample prepared in Step B, stir evenly and then drip it into a 2.5 wt% calcium chloride solution to obtain catalyst pellets, wash the pellets with deionized water, transfer the sample to an oven at 70 °C and dry it for 10 h to obtain a modified alumina solid base catalyst.

[0040] The specific surface area of the prepared sample is: 283.23 m 2 ·g -1 , the pore volume: 0.43 cm 3 ·g -1 , the regeneration amount of diethyl anthraquinone: 10.73 g·L -1 (50 °C, 5 g of catalyst, 50 mL of working solution, react for 72 h).

[0041] Example 4

[0042] Step A: Weigh 8.00 g of magnesium oxide into a beaker, then add 80 mL of 1 mol / L dilute hydrochloric acid solution to the beaker, stir at a speed of 700 rpm, react at 70 °C for 4 h, centrifuge and collect the obtained slurry, wash it until the pH is neutral, then transfer the sample to an oven at 60 °C and dry it for 12 h, and grind it into powder for standby.

[0043] Step B: Add 4.00 g of the powder prepared in Step A into a beaker, add 50 mL of anhydrous ethanol, place the beaker on a magnetic stirring table and stir at 700 rpm for 2 h to disperse it fully. Then, slowly add 10 mL of bis[3-(trimethoxysilyl)propyl]amine under a nitrogen atmosphere, continue stirring for 2 h, slowly drip 150 mL of deionized water through a peristaltic pump. After the addition, continue stirring and reacting at 75 °C for 6 h. Then, wash the obtained slurry with ethanol, and after centrifugal separation, place the obtained wet material in an oven at 70 °C and dry for 12 h.

[0044] The specific surface area of the prepared sample is: 167.38 m 2 ·g -1 , pore volume: 0.36 cm 3 ·g -1 , regeneration amount of diethylanthraquinone: 13.35 g·L -1 ((50 °C, 5 g of catalyst, 50 mL of working solution, reaction for 72 h).

[0045] Step C: Dissolve 0.5 g of sodium alginate in 50 mL of deionized water, add 3.5 g of the powder sample prepared in Step B, stir evenly and then drip it into a 1.0 wt% calcium chloride solution to obtain catalyst pellets. Wash the pellets with deionized water, transfer the sample to an oven at 60 °C and dry for 12 h to obtain a modified magnesium oxide solid base catalyst.

[0046] Comparative Example 1

[0047] Currently commercially available activated alumina regeneration catalyst, specific surface area: 185.25 m 2 ·g -1 , pore volume: 0.31 cm 3 ·g -1 , regeneration amount of 2-ethylanthraquinone: 0.24 g·L -1 ((50 °C, 3 g of catalyst, 50 mL of working solution, reaction for 72 h).

[0048] The above has detailed the examples of the present invention in combination with the embodiments. However, the present invention is not limited to the above examples. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention, and these should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a solid base catalyst for regenerating anthraquinone degradation products in the working solution during the production of hydrogen peroxide by the anthraquinone process, characterized in that, The preparation method specifically includes the following steps: Step A: Weigh a certain amount of catalyst material into a first beaker, add a certain amount of dilute hydrochloric acid solution with a concentration of 0.5 - 10 mol / L, stir at a speed of 400 - 900 rpm, react at 20 - 80 °C for 1 - 10 h to obtain a first slurry. Centrifuge and collect the first slurry, wash it until the pH is neutral to obtain a treated slurry. Then transfer part of the treated slurry into an oven at 50 - 80 °C and dry it for 12 - 48 h, and grind it into powder for standby; Step B: Add the powder prepared in Step A into a second beaker, add a certain amount of organic solvent and stir at a speed of 500 - 800 rpm for 0.5 - 5 h to make it fully dispersed. Place the second beaker on a magnetic stirring table, and then slowly drop a certain amount of modifier under a N2 atmosphere, continue stirring for 1 - 10 h. Slowly drip deionized water through a peristaltic pump, and then continue stirring and reacting at 20 - 80 °C for 1 - 10 h to obtain a second slurry. Then wash the second slurry with ethanol, and after centrifugal separation, obtain a wet material. Place the wet material in an oven at 50 - 80 °C and dry it for 12 - 48 h to obtain a powder sample; Step C: Dissolve an appropriate amount of sodium alginate in deionized water to obtain a solution. Add the powder sample prepared in Step B into the solution, stir evenly and then drop it into calcium chloride solution. Through ion exchange, calcium alginate is formed to solidify the droplets to obtain catalyst pellets. Wash the catalyst pellets with deionized water, and then transfer them into an oven at 50 - 80 °C and dry them for 10 - 48 h to obtain a solid base catalyst; Among them, the organic solvent in Step B is any one of anhydrous ethanol, propanol, ethylene glycol, glycerol, and butanol, and the modifier is selected from one or more of 3 - aminopropyltriethoxysilane, N-(β - aminoethyl)-γ - aminopropyltrimethoxysilane, or bis[3-(trimethoxysilyl)propyl]; 2. The preparation method according to claim 1, characterized in that: The solid - liquid ratio of the catalyst material to the dilute hydrochloric acid solution in Step A is 1:1 - 1:

30.

3. The preparation method according to claim 1, characterized in that: The organic solvent in Step B is anhydrous ethanol; the liquid - solid ratio of the dosage of the organic solvent to the dosage of the powder is 10:1 - 1:

10.

4. The preparation method according to claim 1, characterized in that: The liquid - solid ratio of the modifier to the catalyst material in Step B is 0.1 - 4 mL / g.

5. The preparation method according to claim 1, characterized in that: The volume ratio of the dosage of deionized water to the organic solvent in Step B is 0 - 100, where the dosage of deionized water is not 0.

6. The preparation method according to claim 1, characterized in that: The concentration of the calcium chloride solution in Step C is 0.1 - 10 wt%.

7. The preparation method according to claim 1, characterized in that: The mass ratio of sodium alginate to the catalyst material in Step C is 1:1 - 1:

10.

8. The preparation method according to claim 1, wherein: The catalyst material in Step A includes: attapulgite, alumina, magnesia, or a composite material of any two of them.

9. A solid base catalyst, characterized in that: Prepared by the preparation method of the solid base catalyst according to any one of claims 1-8, the specific surface area of the solid base catalyst is 100-800 m 2 ·g -1 , the pore volume is 0.3-3.0 cm 3 ·g -1 , and the particle size is 1-10 mm.

10. Application of a solid base catalyst, characterized in that, The solid base catalyst is prepared by the preparation method of the solid base catalyst according to any one of claims 1 - 8, and this catalyst is used for the regeneration of anthraquinone degradation products in the working solution during the production of hydrogen peroxide by the anthraquinone method.

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