CN102294240B - Pd/C catalyst for producing 2,3,5-trimethylhydroquinone (TMHQ) by virtue of hydrogenation of 2,3,5-trimethylbenzoquinone (TMBQ) and preparation method thereof - Google Patents

Abstract

The invention relates to a Pd/C catalyst used for TMBQ hydrogenation to produce TMHQ and a preparation method. In the Pd/C catalyst of the present invention, the precious metal Pd loaded on the carrier activated carbon exists in the form of nanoparticles, the Pd dispersion degree is not lower than 30%, and the carrier activated carbon has micropores and mesopores. The preparation method of the present invention comprises the following steps: (1) acid treatment of the carrier activated carbon, adding the acid solution into the activated carbon to carry out water bath reflux treatment; (2) washing the acid-treated activated carbon with deionized water to neutrality, after drying, To obtain an activated carbon carrier; (3) pre-soaking the activated carbon carrier with an infiltration solution; (4) slowly adding a Pd source solution with a concentration of 0.01 to 0.3 mol/L into the pre-soaked activated carbon carrier, so that Pd is loaded on the activated carbon , to obtain a catalyst precursor; (5) the catalyst precursor is dried and treated by a reduction method to obtain a Pd/C catalyst for TMBQ hydrogenation to produce TMHQ. The invention is simple, effective and has the characteristics of high catalytic performance in BTOP reaction.

Description

A kind of Pd/C catalyst and preparation method for TMBQ hydrogenation production TMHQ

technical field

The invention relates to a supported noble metal catalyst for liquid-phase catalytic hydrogenation and a preparation method thereof, in particular to a method for hydrogenation of TMBQ (2,3,5-trimethylbenzoquinone) to produce TMHQ (2 , 3,5-trimethylhydroquinone) Pd/C catalyst and preparation method.

Background technique

Vitamin E (VE) is not only used as an additive in medicine, health products, food, and cosmetics, but also as an industrial antioxidant. It has become a hot product that has attracted much attention in recent years. The demand for VE in the domestic and foreign markets has increased sharply, and the price has continued to rise. Therefore, timely production and expansion of VE production will bring better economic benefits.

TMHQ (2,3,5-trimethylhydroquinone) is a white powdery organic substance, an important intermediate for the synthesis of vitamin E, which reacts with isophytol to synthesize VE. However, the production technology of such intermediates has been monopolized by large foreign companies for a long time, which makes the production of VE in my country restricted by raw materials and intermediates, and lacks competitiveness in the international market. Although in recent years, the domestic Zhejiang Chemical Industry Research Institute and other units have successfully developed the m-cresol method to synthesize TMHQ technology, which has promoted the production of VE in my country, but because the development of this technology has just started, the technology is advanced and mature compared with similar foreign companies. There is a clear gap. Therefore, further research on the synthesis of TMHQ is of great significance to the development of domestic VE production.

The methods for synthesizing TMHQ from TMBQ mainly include chemical reduction and catalytic hydrogenation reduction. The chemical reduction method is generally to sulfonate the raw material 2,3,6-trimethylphenol (TMP) first to generate 4-sulfonic acid-2,3,6-trimethylphenol, and then oxidize it with an oxidizing agent (such as MnO ₂ ) TMBQ is generated, and then reduced to TMHQ by a reducing agent (such as hydrosulfite). Chinese enterprises basically use this production process to produce TMHQ. In actual production, the solid 4-sulfonic acid group-2,3,6-trimethylphenol generated after TMP sulfonation tends to agglomerate, and these blocky solids must be dissolved before oxidation with _MnO2 , which is cumbersome and time-consuming. . In addition, the reduction process not only produces a large amount of waste liquid, but also inevitably introduces impurities to reduce the quality of TMHQ. The catalytic hydrogenation method refers to the process of directly reducing TMBQ to TMHQ under the action of a catalyst in a hydrogen atmosphere. This method has the characteristics of high product quality and low cost, and is currently a production method commonly used by large foreign companies. .

Since VE is mainly used in the fields of medicine and food additives, as an important raw material for the production of TMHQ, its production purity affects the performance and quality of downstream products. Based on the process of preparing TMHQ by catalytic hydrogenation reduction of TMBQ, the difficulty now is to develop an efficient catalyst for the directional conversion of TMBQ into TMHQ in a suitable solvent.

US Patent No. 3,839,468 investigated the effect of the solvent on the hydrogenation reduction of TMBQ to TMHQ under the action of a Pd-based catalyst. It is found that when C ₃ -C ₅ alcohol is used as a solvent, the product is colored (air oxidized) less than when C ₁ -C ₂ alcohol is used as a solvent. The coloring is due to the combination of TMBQ and TMHQ to form a quinhydrone complex, quinhydrone Quinone is black in the solid state, and it is the presence of this substance that gives TMHQ its color. When aliphatic ketones (C ₃ -C ₆ ) were used as solvents, the lifetime of Pd-based catalysts was prolonged and the purity of TMHQ was higher. U.S. Patent US4769500 mentions a heterogeneous catalytic hydrogenation catalyst in which noble metal Pd is loaded onto alkali metal-containing aluminosilicates. Under normal pressure and a reaction temperature of 40°C, the conversion rate of TMBQ reaches 100%, and the selectivity of TMHQ is also high. 99%, and the catalyst can be reused. However, this patent does not clarify the structure and specific composition of the carrier aluminosilicate, nor does it mention the specific preparation steps of the catalyst.

Since the catalytic hydrogenation reaction is carried out on the surface of metal Pd, generally for catalysts with the same loading amount of noble metal Pd, the higher the dispersion of Pd in the catalyst, the higher the activity. If the Pd compound (such as chloropalladic acid, or sodium chloropalladate) solution is directly loaded on the activated carbon, a thin shiny metal Pd layer will appear on the surface of the activated carbon, mainly because the surface of the activated carbon contains hydroxyl and aldehyde groups. These groups can easily reduce Pd cations to zero-valent metal Pd. Therefore, the dispersion of noble metal Pd in the catalysts prepared in this way is generally very low. One of the effective methods to overcome this technical problem is to convert the Pd ions in the impregnation solution containing Pd compounds into insoluble compounds before impregnation. For example, the water-soluble compound of Pd is hydrolyzed into insoluble Pd(OH) ₂ or PdO at room temperature, and then loaded on activated carbon, and then reduced with a reducing agent, which can prevent the migration of Pd and particle growth. US Pat. No. 3,138,560 adds hydrogen peroxide to the impregnation solution to hydrolyze the water-soluble compound of Pd to form an insoluble compound, and then impregnates it. However, because hydrogen peroxide itself is also oxidizing, it can oxidize the surface groups of activated carbon, which will change the physical and chemical properties of the support surface, that is, change the surface group structure of the support, thus causing uncertain negative effects on the catalyst. U.S. Patent No. 4,476,242 proposes to use organic substances such as methanol or pyridine to prepare an impregnation solution containing Pd compounds, which is very effective in inhibiting the migration of Pd and particle growth, but the preparation process uses methanol or pyridine, which is harmful to the human body. The angle of protection is unfavorable. In addition, European patent EP08150726.1 reported that under the action of surfactant, Pd cations were reduced to zero-valent metal Pd sols by adjusting the pH value, and then loaded on activated carbon to prepare Pd/C catalysts. High, it is difficult to distribute Pd evenly on the carrier activated carbon, which leads to a decrease in the dispersion of Pd.

In summary, although the existing Pd/C catalyst can show high selectivity, it has the disadvantages of low dispersion of noble metal Pd and low catalytic activity in the process of catalyzing the hydrogenation of TMBQ to TMHQ.

Contents of the invention

The present invention aims at the low dispersion of precious metal Pd existing in the existing Pd/C catalyst, and the deficiency that the catalytic activity is not high in the process of catalyzing TMBQ hydrogenation to synthesize TMHQ, and provides a kind of precious metal Pd with high dispersion, which is catalytic in TMBQ In the process of hydrogenation to produce TMHQ, it not only has high selectivity, but also has high catalytic activity in TMBQ catalytic hydrogenation reaction for TMBQ (2,3,5-trimethylbenzoquinone) hydrogenation to produce TMHQ (2,3, 5-trimethylhydroquinone) Pd/C catalyst and preparation method.

The present invention is accomplished through the following technical solutions, a Pd/C catalyst for TMBQ hydrogenation to produce TMHQ, wherein the noble metal Pd loaded on the carrier activated carbon exists in the form of nanoparticles, and the dispersion of Pd is not less than 30%, The carrier activated carbon is coconut shell-type activated carbon, and the carrier activated carbon has micropores and mesopores, and the volume of the mesopores is 5 to 6 times that of the micropores.

In the Pd/C catalyst used for hydrogenation of TMBQ to produce TMHQ, the size of Pd nanoparticles is 2.0-5.0 nm.

In the Pd/C catalyst used for TMBQ hydrogenation to produce TMHQ, the specific surface area of the carrier activated carbon is greater than 1000m ² /g, and the mesopore size on the carrier activated carbon is 2-10nm.

A kind of preparation method of the Pd/C catalyst that the present invention is used for TMBQ hydrogenation to produce TMHQ comprises the following steps:

(1) Acid treatment of carrier activated carbon, acid solution is added in activated carbon, water bath reflux treatment 2～4h, acid solution adopts a kind of in hydrochloric acid, phosphoric acid or nitric acid solution;

(2) Repeatedly washing the acid-treated activated carbon with deionized water to neutrality, and drying at 80-120° C. for 0.5-10 hours to obtain a pretreated activated carbon carrier;

(3) Pre-soak the pretreated activated carbon carrier with the soaking solution for 0.2 to 5 hours, the concentration of the soaking solution is 0.1 to 2 mol/L, and the ratio of the mass of the soaking solution to the mass of the activated carbon is 0 to 4;

(4) Slowly add the Pd source solution with a concentration of 0.01-0.3mol/L to the pre-soaked activated carbon carrier, so that Pd is loaded on the activated carbon to obtain a catalyst precursor, wherein the mass of metal Pd added is based on the total amount of the catalyst. The mass is 1.0～5.0wt.%;

(5) The catalyst precursor is dried and treated by a reduction method to obtain a Pd/C catalyst for TMBQ hydrogenation to produce TMHQ.

In the preparation method of the Pd/C catalyst used for hydrogenation of TMBQ to produce TMHQ, the concentration of the acid solution used in step (1) is 5wt.%-10wt.%.

In the preparation method of a Pd/C catalyst used for hydrogenation of TMBQ to produce TMHQ, the particle size of the carrier activated carbon is 180-220 mesh, preferably 200 mesh.

In the preparation method of the Pd/C catalyst used for hydrogenation of TMBQ to produce TMHQ, the drying time after the activated carbon acid treatment of the carrier is preferably 0.5-4 hours.

In the preparation method of a Pd/C catalyst used for hydrogenation of TMBQ to produce TMHQ, the soaking solution used in step (3) is one of sodium carbonate solution or oxalic acid solution.

In the preparation method of described a kind of Pd/C catalyst that is used for TMBQ hydrogenation to produce TMHQ, the Pd source of the Pd source solution used in step (4) is acetate, nitrate, hydrochloride of Pd , a kind of in chloropalladic acid, palladium ammonium complex or organic palladium, preferably a kind of in chloropalladic acid or sodium chloropalladate.

In the described preparation method of a Pd/C catalyst used for TMBQ hydrogenation to produce TMHQ, the reduction method used in step (5) is hydrogen reduction, formaldehyde reduction, ethylene glycol reduction, formic acid reduction, sodium formate reduction One of them, preferably one of hydrogen reduction or formaldehyde reduction.

Compared with the existing method for preparing Pd/C catalyst, the present invention is characterized in that: before impregnating the Pd compound, the carrier activated carbon is pretreated with acid, and then modified by adding an appropriate immersion solution, because the immersion solution can The interaction with the oxygen-containing groups on the carrier activated carbon increases the reduction potential of the carrier. When Pd is loaded on the activated carbon, the Pd cations will not be reduced by the modified carrier surface groups, so that Pd can be very uniformly distributed on the surface of the carrier activated carbon. In addition, the present invention also has: the prepared noble metal Pd catalyst has high dispersion, Pd nanoparticles are uniform, the source of the carrier infiltration solution used is wide, the price is low, the catalyst preparation process is simple, and the prepared catalyst has a high performance in TMBQ catalytic hydrogenation reaction. outstanding catalytic activity.

Among the present invention, adopted CO pulse titration to measure the degree of dispersion of noble metal Pd, degree of dispersion is calculated by the following formula:

Dispersion = (V _absorption × M _Pd ) / (22400 × W _Pd ) × 100%

In the formula: V _suction represents the CO adsorption amount (ml) under the standard state,

M _Pd is the atomic weight of Pd 106.4g·mol ^-1 ,

W _Pd is the mass (g) of Pd in the catalyst.

In the present invention, the size of the noble metal Pd particles of the prepared Pd/C catalyst is analyzed by a transmission electron microscope (TEM) technique.

Catalyst activity evaluation conditions: reactant TMBQ: 10-20g; catalyst dosage in proportion of reactant: 0.05-0.12wt.%; reaction solvent ethyl acetate: 35-65ml; hydrogen initial pressure: 0.5-0.8MPa; reaction temperature : 65～95℃.

评价催化剂的TMBQ加氢活性。Measure the time Δt required for the pressure in the kettle to drop by 0.1MPa, and take the initial hydrogen absorption rate

The catalysts were evaluated for their TMBQ hydrogenation activity.

The feature of the present invention is: by changing the alkali treatment conditions, such as NaOH concentration, temperature and time, etc., the ratio of micropores to mesoporous in the Fe-ZSM-5 microporous mesoporous composite molecular sieve catalyst can be changed, thereby adjusting the alkali treatment before and after Catalytic performance of catalysts in BTOP. Judging from the characterization and reaction evaluation results of the samples, the present invention introduces mesopores into the microporous Fe-ZSM-5 molecular sieve crystals through alkali treatment, and the obtained samples have complete morphology and unchanged crystal structure, while the molecular sieve has remarkable mass transfer performance. Improvement, its catalytic activity and stability in the BTOP catalytic reaction are also significantly improved. Under the optimized alkali treatment conditions, the modified catalyst was reacted at a reaction temperature of 320°C for 3 hours, and the conversion rate of benzene was still maintained at 20%, which was significantly higher than the catalytic activity of the sample without alkali treatment. The selectivity reaches 100%. Compared with the prior art, the present invention provides a simple and effective method for preparing a microporous mesoporous composite Fe-ZSM-5 zeolite molecular sieve catalyst with high catalytic performance in BTOP reaction.

Description of drawings

Fig. 1 is the TEM figure and particle size distribution figure of 5wt.%Pd/C catalyst in embodiment 1.

Fig. 2 is a TEM image and a particle size distribution image of the 2wt.% Pd/C catalyst in Example 4.

Detailed ways

The present invention is further specifically described below by way of examples, but the present invention is not limited to the following examples.

Example 1

Reflux 20g of coconut shell-type activated carbon with a specific surface area greater than 1000m ² /g with 5wt.% nitric acid in a water bath at 60°C for 2 hours, then wash it repeatedly with deionized water until neutral, and dry it by blowing at 80°C 4h standby.

For the preparation of the Pd source impregnation solution, weigh about 3g of PdCl ₂ solid and add it to 7.29ml of concentrated hydrochloric acid. After it is completely dissolved, add deionized water to dilute to a 50ml volumetric flask for later use.

Take 3 g of pretreated activated carbon and add 10 ml of sodium carbonate with a concentration of 0.9 mol/L to pre-soak the activated carbon for 0.5 h. According to the load of Pd being 5.0wt.%, pipette about 14ml of PdCl _solution , add pre-soaked activated carbon and impregnate it for 6h, then put it in a 50°C oven overnight, in 10vol.% H ₂ /Ar (total flow rate : 30ml/min) at 200°C for 2h to obtain a catalyst, and the catalyst was characterized by its dispersion by CO pulse titration. After analysis, its dispersion was 50%.

Catalyst activity evaluation conditions: reactant TMBQ: 15g; reaction solvent ethyl acetate: 50ml; hydrogen initial pressure: 0.6MPa; reaction temperature: 80°C; catalyst: 0.012g.

Catalyst activity evaluation results: the time required to reduce 0.1MPa was recorded as 4.5min, and the hydrogen absorption rate was 648ml·(min g) ^-1 .

Example 2

20g of powdered activated carbon with a specific surface area greater than 1000m ² /g was refluxed with 5wt.% nitric acid in a water bath at 60°C for 2h, then washed repeatedly with deionized water until neutral, and dried at 80°C for 4h for later use.

For the preparation of the Pd source impregnation solution, weigh about 3g of PdCl ₂ solid and add it to 7.29ml of concentrated hydrochloric acid. After it is completely dissolved, add deionized water to dilute to a 50ml volumetric flask for later use.

Take 3 g of pretreated activated carbon and add 10 ml of oxalic acid with a concentration of 0.1 mol/L to pre-soak the activated carbon for 0.5 h. According to the load of Pd is 5.0wt%, pipette about 14ml of _PdCl2 solution, add pre-soaked activated carbon to impregnate for 6h, and then put it in a 50°C oven overnight, in 10vol.% _H2 /Ar (total flow rate: 30ml/min) atmosphere at 200°C for 2h to obtain the catalyst, and the dispersion of the catalyst was characterized by CO pulse titration. After analysis, the dispersion was 45%.

Catalyst activity evaluation conditions: reactant TMBQ: 15g; reaction solvent ethyl acetate: 50ml; hydrogen initial pressure: 0.6MPa; reaction temperature: 80°C; catalyst: 0.012g.

Catalyst activity evaluation results: the time required to reduce 0.1MPa was recorded as 4.9min, and the hydrogen absorption rate was 595ml·(min g) ^-1 .

Example 3

Reflux 20g of coconut shell-type activated carbon with a specific surface area greater than ^1000m2 /g with 10wt.% nitric acid in a water bath at 60°C for 2 hours, then repeatedly wash it with deionized water until neutral, and dry it by blowing at 80°C 4h standby.

For the preparation of the Pd source impregnation solution, weigh about 3g of PdCl ₂ solid and add it to 7.29ml of concentrated hydrochloric acid. After it is completely dissolved, add deionized water to dilute to a 50ml volumetric flask for later use.

Take 3 g of pretreated activated carbon and add 10 ml of oxalic acid with a concentration of 0.1 mol/L to pre-soak the activated carbon for 0.5 h. According to the load of Pd is 5.0wt%, pipette about 14ml of _PdCl2 solution, add pre-soaked activated carbon to impregnate for 6h, and then put it in a 50°C oven overnight, in 10vol.% _H2 /Ar (total flow rate: 30ml/min) atmosphere at 200°C for 2h to obtain the catalyst, and the dispersion of the catalyst was characterized by CO pulse titration. After analysis, the dispersion was 43%.

Catalyst activity evaluation conditions: reactant TMBQ: 15g; reaction solvent ethyl acetate: 50ml; hydrogen initial pressure: 0.6MPa; reaction temperature: 80°C; catalyst: 0.012g.

Catalyst activity evaluation results: It was recorded that the time required to decrease 0.1MPa was 10.5min, and the hydrogen absorption rate was 648ml·(min g) ^-1 .

Example 4

20g of powdered activated carbon with a specific surface area greater than ^1000m2 /g was refluxed with 10wt.% nitric acid in a water bath at 60°C for 2h, then repeatedly washed with deionized water until neutral, and then air-dried at 80°C for 4h for later use.

For the preparation of the Pd source impregnation solution, weigh about 3g of PdCl ₂ solid and add it to 7.29ml of concentrated hydrochloric acid. After it is completely dissolved, add deionized water to dilute to a 50ml volumetric flask for later use.

Take 3 g of pretreated activated carbon, add 2.8 ml of Na ₂ CO ₃ with a concentration of 1.62 mol/L and stir evenly. According to the Pd load of 2.0wt%, pipette about 1ml of _PdCl2 solution, add water to it to dilute the _PdCl2 solution at the same time, add pre-soaked activated carbon to soak for 6h, then put it in a 50°C oven overnight, and place it in a 10vol. The catalyst was obtained by reduction at 200° C. for 2 h in an atmosphere of % H ₂ /Ar (total flow rate: 30 ml/min), and the dispersion degree of the catalyst was characterized by CO pulse titration. After analysis, the dispersion degree was 35%.

Catalyst activity evaluation conditions: reactant TMBQ: 15g; reaction solvent ethyl acetate: 50ml; hydrogen initial pressure: 0.6MPa; reaction temperature: 80°C; catalyst: 0.012g.

Catalyst activity evaluation results: the time required to reduce 0.1MPa was recorded as 6.2min, and the hydrogen absorption rate was 470ml·(min g) ^-1 .

Comparative example 1

The 5.0wt.% Pd/C catalyst purchased from a domestic Pd/C catalyst manufacturer was characterized by CO pulse titration. After analysis, the dispersion was 26%.

Catalyst activity evaluation conditions: reactant TMBQ: 15g; reaction solvent ethyl acetate: 50ml; hydrogen initial pressure: 0.6MPa; reaction temperature: 80°C; catalyst: 0.012g.

Catalyst activity evaluation results: It was recorded that the time required to decrease 0.1 MPa was 11.5 mm, and the hydrogen absorption rate was 254 ml·(min g) ^-1 .

Claims (8)

1. A Pd/C catalyst for TMBQ hydrogenation to produce TMHQ is characterized in that described Pd/C catalyst wherein the noble metal Pd loaded on the carrier activated carbon exists in the form of nanoparticles, and the Pd dispersion is not less than 30% , the carrier activated carbon is coconut shell-type activated carbon, the carrier activated carbon has micropores and mesopores, and the volume of the mesopores is 5-6 times that of the micropores, the size of the Pd nanoparticles is 2.0-5.0 nm, and the specific surface area of the carrier activated carbon Greater than 1000 m ² /g, the mesopore size on the carrier activated carbon is 2-10 nm. 2. a kind of preparation method for the Pd/C catalyst of TMBQ hydrogenation production TMHQ according to claim 1 is characterized in that this preparation method comprises the following steps: ⑴ For the acid treatment of the carrier activated carbon, add the acid solution to the activated carbon, reflux the water bath for 2-4 hours, and use one of the hydrochloric acid, phosphoric acid or nitric acid solutions for the acid solution; (2) Repeatedly wash the acid-treated activated carbon with deionized water to neutrality, and dry it at 80-120 °C for 0.5-10 h to obtain the pretreated activated carbon carrier; (3) Pre-soak the pretreated activated carbon carrier with the soaking solution for 0.2-5 hours, the concentration of the soaking solution is 0.1-2 mol/L, and the ratio of the mass of the soaking solution to the mass of activated carbon is 0-4, excluding 0 point; (4) Slowly add the Pd source solution with a concentration of 0.01 to 0.3 mol/L to the pre-soaked activated carbon carrier dropwise, so that Pd is loaded on the activated carbon to obtain a catalyst precursor, in which the mass of metal Pd added is based on the total mass of the catalyst 1.0～5.0 wt.%; ⑸ After the catalyst precursor is dried, it is treated with a reduction method to obtain a Pd/C catalyst for TMBQ hydrogenation to produce TMHQ. 3. a kind of preparation method for the Pd/C catalyst of TMBQ hydrogenation production TMHQ according to claim 2 is characterized in that the concentration of the acid solution used in described step (1) is 5 wt.%～10 wt.%. 4. A method for preparing a Pd/C catalyst for TMBQ hydrogenation to produce TMHQ according to claim 2, characterized in that the particle size of the carrier activated carbon is 180-220 mesh. 5. a kind of preparation method for the Pd/C catalyst of TMBQ hydrogenation production TMHQ according to claim 2 is characterized in that the soaking liquid used in step (3) is the one in sodium carbonate solution or oxalic acid solution. 6. a kind of preparation method for the Pd/C catalyst of TMBQ hydrogenation production TMHQ according to claim 2 is characterized in that the Pd source of the Pd source solution used in step (4) is acetate, nitric acid of Pd One of salt, hydrochloride, chloropalladium acid, palladium ammonia complex or organic palladium. 7. a kind of preparation method for the Pd/C catalyst of TMBQ hydrogenation production TMHQ according to claim 2 is characterized in that the reduction method used in step (5) is hydrogen reduction, formaldehyde reduction, ethylene glycol reduction, One of formic acid reduction and sodium formate reduction. 8. a kind of preparation method for the Pd/C catalyst of TMBQ hydrogenation production TMHQ according to claim 3 is characterized in that this preparation method comprises the following concrete steps: ⑴ For the acid treatment of the carrier activated carbon, add the acid solution to the activated carbon, and reflux the water bath for 2 to 4 hours. The acid solution is one of hydrochloric acid, phosphoric acid or nitric acid solution, and the particle size of the carrier activated carbon is 180 to 220 mesh; (2) Repeatedly wash the acid-treated activated carbon with deionized water to neutrality, and dry it at 80-120 °C for 0.5-10 h to obtain the pretreated activated carbon carrier; (3) Pre-soak the pretreated activated carbon carrier with the soaking solution for 0.2-5 hours, the concentration of the soaking solution is 0.1-2 mol/L, and the ratio of the mass of the soaking solution to the mass of the activated carbon is 0-4, excluding the 0 point, One of sodium carbonate solution or oxalic acid solution is used as the immersion solution; (4) Slowly add the Pd source solution with a concentration of 0.01 to 0.3 mol/L to the pre-soaked activated carbon carrier dropwise, so that Pd is loaded on the activated carbon to obtain a catalyst precursor, in which the mass of metal Pd added is based on the total mass of the catalyst The Pd source of the Pd source solution is one of Pd acetate, nitrate, hydrochloride, chloropalladium acid, palladium ammonia complex or organic palladium; ⑸ After the catalyst precursor is dried, it is treated with one of hydrogen reduction, formaldehyde reduction, ethylene glycol reduction, formic acid reduction, and sodium formate reduction to obtain a Pd/C catalyst for TMBQ hydrogenation to produce TMHQ.

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