CN112973677A

CN112973677A - Preparation method and application of hydrophobic noble metal catalyst

Info

Publication number: CN112973677A
Application number: CN201911283660.4A
Authority: CN
Inventors: 刘俊义; 王树东; 肖伟; 苏宏久; 郭翔; 杨晓野; 付鹏兵; 李大卫; 刘重阳; 严华
Original assignee: Dalian Institute of Chemical Physics of CAS; Shanxi Luan Mining Group Co Ltd
Current assignee: Dalian Institute of Chemical Physics of CAS; Shanxi Luan Mining Group Co Ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2021-06-18

Abstract

The application discloses a preparation method of a hydrophobic noble metal hydrogenation catalyst, which at least comprises the following steps: a) obtaining a modified precursor A of a silicon dioxide carrier; b) bonding and reacting the silicon dioxide modified precursor A and a silanization reagent in a solvent to obtain a silicon dioxide modified carrier B; c) loading a precursor containing noble metal active elements on a modified silicon dioxide carrier B, and roasting to obtain an oxidation state precursor C; d) and reducing the oxidation state precursor C to obtain the hydrophobic noble metal hydrogenation catalyst. Meanwhile, the application of the hydrophobic noble metal hydrogenation catalyst prepared by the method in preparation of hydrogen peroxide by anthraquinone catalytic hydrogenation is disclosed, the hydration effect of water in a hydrogenation working solution on active components is avoided, the desorption effect of anthrahydroquinone which is a species after anthraquinone hydrogenation is further improved, and the selectivity and the stability of the hydrogenation catalyst are improved.

Description

Preparation method and application of hydrophobic noble metal catalyst

Technical Field

The application relates to a preparation method and application of a hydrophobic noble metal catalyst, belonging to the technical field of chemical production.

Background

The final product decomposed in the using process of the hydrogen peroxide is mainly water, secondary pollutants can not be generated, and the hydrogen peroxide is an environment-friendly chemical. As a green chemical product, the hydrogen peroxide can be used as an oxidant, a bleaching agent, a disinfectant, a polymer initiator and the like, and is widely applied to the industries of chemical synthesis, papermaking, spinning, environmental protection, food, electronics, aerospace and the like.

The anthraquinone process is the main process for producing hydrogen peroxide in the world at present. In the anthraquinone hydrogenation process, the most important step is the hydrogenation process of the anthraquinone, and the solid catalyst has great influence on the energy consumption and the material consumption of an anthraquinone hydrogenation system.

Drelinkiewicz et al, Bowland scientific institute, proposed (Chemical Papers,2013,67(8), 1087-. Although researchers have adopted polymers as carriers to improve the dispersion degree of noble metal components and further improve the hydrogenation activity of the catalyst, the desorption rate of the anthrahydroquinones is very low, the anthrahydroquinones are easy to further react with hydrogen to generate hydrogenation side reactions such as ketones and phenols, and the generated side reactions not only cause the loss of effective anthraquinones but also cause the deactivation of the catalyst, and most importantly, the side reactions are the main reaction paths causing the reduction of anthraquinone selectivity. The Corain research group in Italy (Journal of Molecular Catalysis A: Chemical,2003,194:273-281) proposed the use of hydrophobic resins as the carrier of hydrogenation catalysts, and found that Pd ions can exist on the surface of the carrier of the catalyst in an atomic state and that the size of Pd particles can reach 3nm, showing a relatively suitable hydrogenation Chemical selectivity, which is lower than that of commercial catalysts in terms of chemisorption of anthrahydroquinones. However, researchers do not consider the interaction between the subsequent carrier and the catalyst, so that the acting force between the catalyst carrier and the active component is weak, the active component of the catalyst is easy to lose, the activity of the catalyst is further reduced, and the catalyst is difficult to be practically applied.

Therefore, how to realize a hydrogenation catalyst with high selectivity, high activity and high stability is still a great challenge.

Disclosure of Invention

According to the hydrogenation catalyst disclosed by the application, a silicon oxide carrier is pretreated, so that more hydroxyl groups are exposed on a micron silicon dioxide carrier, and then organic groups are introduced by a silane reagent for chemical bonding, so that the hydrophobicity and polarity of the carrier are adjusted. And finally, carrying the active component on a hydrophobic micron silica carrier by carrying the active component, and roasting and reducing to obtain the hydrophobic noble metal hydrogenation catalyst. The noble metal hydrogenation catalyst prepared by the method avoids the hydration of water in the hydrogenation working solution to active components, further improves the desorption of anthrahydroquinone which is a species after anthraquinone hydrogenation, and improves the selectivity and stability of the hydrogenation catalyst.

According to one aspect of the present application, there is provided a method for preparing a hydrophobic noble metal hydrogenation catalyst, characterized by comprising at least the steps of:

a) obtaining a modified precursor A of a silicon dioxide carrier;

b) bonding and reacting the silicon dioxide modified precursor A and a silanization reagent in a solvent to obtain a silicon dioxide modified carrier B;

c) loading a precursor containing noble metal active elements on a modified silicon dioxide carrier B, and roasting to obtain an oxidation state precursor C;

d) and reducing the oxidation state precursor C to obtain the hydrophobic noble metal hydrogenation catalyst.

Optionally, it is characterized in that step a) is a modified precursor a of the silica support obtained by treating silica with an alkaline or acidic solution.

Optionally, the silica has a particle size of 20 to 300 μm, an average pore diameter of 10 to 30nm, a pore volume of less than 0.75cc/g, and a specific surface area of 140 to 180m²/g。

Optionally, the alkaline solution is selected from at least one of an inorganic alkaline solution and an organic alkaline solution.

Alternatively, the inorganic alkali solution is selected from an inorganic alkali solution such as a sodium hydroxide solution, a potassium hydroxide solution, an aqueous ammonia solution, and the like.

Optionally, the organic base solution is selected from at least one of a tetramethylammonium hydroxide solution, a tetraethylammonium hydroxide solution, ethanolamine, diethanolamine, and triethanolamine solution.

Optionally, the pH value of the alkaline solution is controlled to be 9-11.5.

Alternatively, the pH of the alkaline solution is controlled at 10.8.

Optionally, the mass ratio of the silica to the alkaline solution is 1:5 to 1: 15.

Alternatively, the mass ratio of the silica to the alkaline solution is 1: 10.

Optionally, the acidic solution is at least one selected from a hydrofluoric acid solution, a hydrochloric acid solution and a sulfuric acid solution.

Optionally, the pH value of the acidic solution is controlled to be between 2 and 4.

Alternatively, the pH of the acidic solution is controlled at 3.2.

Optionally, the mass ratio of the silica to the acidic solution is 1:3 to 1: 15.

Optionally, the mass ratio of the silica to the acidic solution is 1: 3-1: 10.

Alternatively, the mass ratio of the silica to the acidic solution is 1: 10.

Optionally, the treatment temperature is between 40 and 95 ℃; the treatment time is 6-96 hr.

Optionally, the treatment temperature is between 60 and 80 ℃; the treatment time is 24-72 hr.

Through the above treatment process, the surface hydroxyl groups of the silicon dioxide are activated, and active sites are provided for the subsequent surface functional group modification.

Optionally, in step b), the silylating agent is selected from at least one of methyltrimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, methyltriethoxysilane, perfluorooctyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane.

Optionally, in step b), the solvent comprises at least one of toluene, ethylbenzene, xylene, chloroform, anhydrous ethanol, anhydrous methanol, and anhydrous isopropanol.

Optionally, the organic solvent has a water content of not higher than 1%.

Optionally, in step b), the ratio of the number of moles of the organic group-containing silylation agent to the total surface area of the silica-modified precursor A is about 1 to 10:10^-6。

Optionally, in the step b), the bonding reaction temperature is 90-150 ℃, and the bonding reaction time is 6-24 hr.

Alternatively, in step b), the bonding reaction temperature is 120 ℃ and the bonding reaction time is 12 hr.

After the reaction, filtering and drying to obtain the required bonding silica carrier, wherein the silica carrier has better hydrophobicity, the hydrophobicity of the silica carrier can be regulated, and the mass ratio of the organic matter content of the modified silica to the bare silica is regulated to be 1-20 wt%.

Optionally, in step c), the precursor containing the noble metal active element is a salt compound containing the noble metal active element.

Optionally, the salt compound containing the noble metal active element is at least one selected from platinum acetate, platinum propionate, palladium (II) acetate, palladium (II) propionate, palladium (II) 2-methyl propionate and palladium trimethyl acetate.

Optionally, in step c), the firing conditions are: the roasting temperature is 200-300 ℃, and the roasting time is 1-5 h.

Optionally, in step c), the firing conditions are: the roasting temperature is 250-350 ℃, and the roasting time is 2-5 h.

Optionally, in step c), the firing conditions are: the roasting temperature is 300 ℃, and the roasting time is 2 h.

Optionally, in step d), the reducing conditions are: the reducing atmosphere is hydrogen, the reducing temperature is 80-100 ℃, and the reducing time is 5-6 h.

Optionally, in step d), the reducing conditions are: the reducing atmosphere is hydrogen, the reducing temperature is 80 ℃, and the reducing time is 5 h.

The application provides a preparation method of a hydrophobic noble metal catalyst, which comprises the steps of carrying out early acid-base treatment on micron-sized silicon dioxide, and then activating hydroxyl on a carrier; then, a silanization reagent with organic groups and the activated silica carrier are subjected to bonding reaction, so that organic groups are introduced onto the silica carrier, the polarity of the silica carrier is changed, and the hydrophobicity of the carrier is improved; finally, the hydrogenation catalyst containing the hydrophobic noble metal is obtained by loading the active element on the modified silicon dioxide carrier, and roasting and reducing the carrier. The preparation method comprises the following specific steps:

a. the pretreatment method comprises the following steps: selecting micron silicon dioxide spherical particles with proper physical characteristics, putting the micron silicon dioxide spherical particles into an alkaline or acidic solution for treatment, and then filtering and drying to obtain a modified precursor A of a silicon dioxide carrier;

b. linkage modification of organic group: putting the silicon dioxide modified precursor into an organic solvent, adding a silane reagent containing a certain group, reacting at a certain temperature, filtering and drying to obtain a silicon dioxide modified carrier B;

c. active component loading: carrying a precursor containing active elements on the modified silicon dioxide carrier B, and then drying and roasting to obtain an oxidation state precursor C;

d. reduction treatment: and reducing the oxidized precursor C to obtain the required hydrophobic noble metal hydrogenation catalyst D.

The micron silicon oxide carrier is mainly used in the liquid phase hydrogenation reaction process of a slurry bed, and specifically, the particle size of the micron silicon oxide is 20-300 mu m, the average pore diameter is 10-30 nm, the pore volume is less than 0.75cc/g, and the specific surface area is 140-180 m²(ii)/g; moreover, in the slurry bed hydrogenation process, the required micron silicon oxide carrier is spherical in shape and is in a monodisperse form.

According to another aspect of the application, a hydrophobic noble metal hydrogenation catalyst prepared by the preparation method is provided, and is characterized in that the mass content of the noble metal active component in the noble metal catalyst is 0.01-2.00 wt%; wherein the content of the active component is calculated by the content of the active element.

Optionally, the mass content of the noble metal active component in the noble metal catalyst is 0.4 wt%.

According to another aspect of the application, a method for preparing hydrogen peroxide by anthraquinone catalytic hydrogenation is provided, which is characterized in that reaction liquid containing anthraquinone raw materials is reacted in a slurry bed containing a catalyst to obtain hydrogen peroxide;

the catalyst contains the hydrophobic noble metal hydrogenation catalyst.

Optionally, the anthraquinone is selected from at least one of ethylanthraquinone, amylanthraquinone, ethyltetrahydroanthraquinone, amyltetrahydroanthraquinone.

Optionally, the inverseThe conditions are as follows: the reaction temperature is 40-60 ℃, the pressure is 0.05-0.3 MPa, and the liquid airspeed is 60-300 h^-1。

Optionally, the reaction conditions are: the reaction temperature is 40-50 ℃, the pressure is 0.01-0.1 MPa, and the liquid airspeed is 60-200 h^-1。

Optionally, the reaction conditions are: the reaction temperature is 40 ℃, the pressure is 0.05MPa, and the liquid space velocity is 60h^-1。

The beneficial effects that this application can produce include:

1) the application discloses a preparation method of a hydrophobic noble metal hydrogenation catalyst, which comprises the steps of exposing more hydroxyl groups on a silicon dioxide carrier through pretreatment of the silicon dioxide carrier, and introducing organic groups through a silane reagent for chemical bonding to adjust the hydrophobicity and polarity of the carrier. And finally, carrying the active component on a hydrophobic silica carrier by carrying the active component, and roasting and reducing to obtain the hydrophobic noble metal hydrogenation catalyst. The noble metal hydrogenation catalyst prepared by the method avoids the hydration of water in the hydrogenation working solution to active components, improves the one-way hydrogen efficiency and the selectivity of effective anthraquinone, further improves the hydrogenation stability of the catalyst, and prevents the loss and inactivation of noble metals.

2) The hydrophobic hydrogenation catalyst prepared by the application contains the silicon dioxide carrier with organic functional groups, so that the polarity of the surface of the catalyst is reduced, hydrogenated intermediate species generated by hydrogenation are easy to desorb from the inside of the catalyst, and the anthraquinone hydrogenation reaction is a complex reaction integrating series and parallel reactions, and is an effective reaction for effective anthraquinone and tetrahydroanthraquinone, and further hydrogenation reaction, so that the anthrahydroquinone species can be easily desorbed by introducing the organic groups, the hydrogenation selectivity can be further improved, a large amount of byproducts are effectively avoided, the stability of the hydrogenation catalyst is improved, and the energy consumption of the reaction is reduced.

Drawings

FIG. 1 is an SEM photograph of sample No. 1 in example 1 of the present application.

FIG. 2 is a graph of hydrogenation efficiency as a function of run time for samples # 1, # 2, and # 4 in example 8 of the present application.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified.

In the present application, microsilica is prepared by laboratory spray drying.

Precursors containing noble metal active elements were purchased from the national pharmaceutical companies.

Example 1

1) Pretreatment method of micron silicon dioxide carrier

Taking 5g of spherical silicon oxide powder with the particle size of 120-400 meshes, and then preparing 50g of ammonia water solution with the mass concentration of 2%. Adding the silicon dioxide powder into an ammonia water solution, and measuring the pH value of the solution to be 10.8; heating the whole solution to 60 deg.C in water bath for aging for 72hr, filtering the mixture, washing, and performing displacement cleaning with ethanol; finally, the filter cake is dried at 120 ℃ overnight.

2) Preparation of hydrophobic silica modification

Adding the dried sample into 15ml of xylene solution, weighing 0.7g of methyltrimethoxysilane into the mixed liquid, heating the mixed solution to 120 ℃, refluxing and aging for 12 hours, filtering the mixed liquid, washing with methanol, and drying a filter cake to obtain an organic functional group modified silicon dioxide sample;

3) supporting of active ingredients

Taking 5g of the spherical modified silicon dioxide powder of the particles, adding 6.5g of palladium acetate organic solution with the concentration of 3mg/ml dissolved by methanol, standing for 2h, drying at 80 ℃ for 6h, and roasting at 300 ℃ for 2h to obtain an oxidation state precursor.

4) Reduction treatment

And putting the oxidized precursor into a tubular furnace, introducing hydrogen with the volume flow of 30ml/min, and reducing at the temperature of 80 ℃ for 5 hours to obtain the required noble metal catalyst which is marked as sample No. 1.

In sample # 1, the mass content of palladium in the noble metal catalyst was 0.4 wt%.

Example 2

1) Pretreatment method of micron silicon dioxide carrier

Taking 5g of spherical silicon dioxide powder with the particle size of 120-400 meshes, and preparing 50g of HF solution with the mass concentration of 1%. Adding the silicon dioxide powder into an aqueous solution of hydrogen fluoride, and measuring the pH value of the solution to be 3.2; heating the whole solution to 80 deg.C in water bath for aging for 24hr, filtering the mixture, washing, and performing displacement cleaning with ethanol; finally, the filter cake is dried at 120 ℃ overnight.

2) Preparation of hydrophobic silica modification

3) supporting of active ingredients

4) Reduction treatment

And putting the oxidized precursor into a tubular furnace, introducing hydrogen with the volume flow of 30ml/min, and reducing at the temperature of 80 ℃ for 5 hours to obtain the required noble metal catalyst which is recorded as sample No. 2.

In sample 2#, the mass content of palladium in the noble metal catalyst was 0.4 wt%.

Example 3

Preparation of samples # 3 to # 5

The preparation method of sample # 3 is different from the preparation method of sample # 1 in that: the pretreatment method of the micron silicon dioxide carrier adopts an organic amine alkali treatment method, the adopted organic amine is tetraethylammonium hydroxide, and the pH value of the solution is adjusted to 10.8; heating the whole solution to 60 deg.C in water bath for aging for 72hr, filtering the mixture, washing, and performing displacement cleaning with ethanol; finally, the filter cake is dried at 120 ℃ overnight. The finally obtained sample was designated as sample # 3. In sample # 3, the mass content of palladium in the noble metal catalyst was 0.4 wt%.

The preparation method of sample # 4 is different from the preparation method of sample # 1 in that: and (3) preparing hydrophobic silica modification, namely adding the dried sample into 15ml of xylene solution, weighing 1.02g of phenyltrimethoxysilane into the mixed liquid, heating the mixed solution to 120 ℃, refluxing and aging for 12 hours, filtering the mixed liquid, washing the mixed liquid with methanol, and finally drying a filter cake to obtain the silica sample modified by the phenyl functional group. The final sample was designated sample # 4. In sample 4#, the mass content of palladium in the noble metal catalyst was 0.4 wt%.

The preparation method of sample # 5 is different from the preparation method of sample # 1 in that: 3mg/ml of palladium acetate organic solution is prepared by dissolving methanol, 3mg/ml of platinum acetate organic solution is prepared by dissolving methanol, and 3.2g of each of the palladium acetate organic solution and the platinum acetate organic solution is taken. The finally obtained sample was designated as sample # 5. In sample No. 5, the mass contents of palladium and platinum in the catalyst were 0.4 wt%.

Example 4

Preparation of silica hydrogenation catalyst

The preparation of the hydrogenation catalyst using silica as a carrier is similar to the method for supporting the active component in the above-mentioned embodiment example 1. Specifically, 20ml of 2mg/ml palladium nitrate aqueous solution is prepared, 2g of spherical silicon dioxide powder with the particle size of 120-400 meshes is weighed, 4ml of the palladium nitrate solution with the prepared concentration is added into the silicon oxide powder, and then the mixture is dried at 120 ℃ and roasted at 350 ℃ for 3 hours to obtain an oxidized palladium catalyst; putting the oxidized palladium catalyst into a tubular furnace, introducing hydrogen with the volume flow of 30ml/min, and reducing at the temperature of 80 ℃ for 5 hours to obtain the hydrogenated palladium catalyst which is marked as 6 #. In sample 6#, the mass content of palladium in the catalyst was 0.4 wt%.

Example 5

Respectively carrying out morphology test on samples 1# to 5# by using a JEOL JSM-7800F Scanning Electron Microscope (SEM).

The test result shows that the grain size of the sample No. 1-5 is 20-300 μm.

Taking sample No. 1 as a typical representative, it can be seen from FIG. 1 that the particle size of sample No. 1 is 40 to 150 μm.

Example 6

The specific surface area, the pore diameter and the pore diameter distribution of the modified silica carrier and the micron silica of the samples 1# to 6# and the samples 1# and 2# are respectively tested by adopting a NOVA2200e type specific surface-pore diameter distribution instrument of the Quanta company in the United states.

The test results are shown in table 1, with samples # 1, # 2, # 3, # 4 and # 6 as typical representatives.

Table 1 physical parameter comparison of hydrophobic catalysts

As can be seen from table 1, the specific surface areas of the catalysts of example 1 (sample # 1), example 2 (sample # 2) and example 3 (sample # 3, 4#) are all smaller than those of the unmodified catalyst example (6#) carrying active components, which indicates that the silica carrier treatment and modification in the previous stage reduce the specific surface area of the catalyst, mainly because the silica material is partially dissolved and re-reacted in the previous stage, and the functional groups modified in the later stage occupy partial pore diameters, thus reducing the specific surface area. Compared with # 2, the pore volume of # 1 is larger, which is mainly caused by the enlargement of the carrier pore channel during the alkaline solution treatment. Compared with No. 1 and No. 3, although the alkaline solution is used for the previous treatment, the pore volume of the catalyst treated by the inorganic ammonia water is larger, which is mainly because the molecular size of the ammonia water is smaller, and the dissolution and re-reaction process of the catalytic carrier is easy. Compared with # 1 and # 4, since the phenyl group is bonded to # 4, the specific surface area and pore volume of # 4 are greatly reduced, so that it can be shown that the phenyl group is relatively large and the occupied space volume is relatively large.

Example 7

The heat loss of the catalyst was measured by a synchronous thermal analyzer (TGA/DSC) model STA 449F3, produced by NETZSCH, germany, to determine the amount of organic functional group bonded to the modified sample. The results of samples 1#, 2#, 4#, 6# are as follows:

TABLE 2

From the thermogravimetric test chart above, the weight loss rate of the samples # 1, # 2 and # 4 is higher than that of the sample # 6, so that the thermogravimetric loss rate of the hydrogenation catalyst modified by organic functional groups as a whole is higher than that of the unmodified sample. The greater heat loss in # 2 compared to the thermogravimetric loss in # 1 and # 2 indicates that more silica hydroxyl groups can be activated and thus more methyl groups can be loaded by treatment with acidic HF, and thus the hydrophobicity of the # 2 sample is higher than that of the # 1 sample. Compared with sample # 1 and sample # 4, the thermogravimetric loss of sample # 4 is relatively large, which indicates that the sample carrying the functional group of phenyl group is heavier than the group weight of methyl group, and the number of C atoms based on phenyl group is higher than that of methyl group, so the sample # 4 is considered to have higher hydrophobicity than sample # 1.

Example 8

Evaluation method of catalyst:

the hydrogenation catalyst was evaluated mainly in a continuous mixed slurry bed reactor. In the experiment, the working solution adopted for evaluation is a mixture of amylanthraquinone and ethylanthraquinone, and the solvent is a mixture of heavy arene and diisobutylcarbinol, wherein the mass ratio of amylanthraquinone to ethylanthraquinone to heavy arene to diisobutylcarbinol is 3: 1: 15: 10. adding 2ml hydrogenation catalyst into the reactor, regulating stirring speed to 1200r/min, controlling hydrogen flow rate to 20ml/min, controlling flow rate of working liquid to 120ml/hr, controlling operation pressure of system to 0.05MPa (gauge pressure), and controlling hydrogenation reaction temperature to 40 deg.C.

Oxidizing the hydrogenated liquid with oxygen, extracting with distilled water, and adding KMnO₄The hydrogen peroxide produced was determined by titration and the hydrogenation efficiency was calculated. The hydrogenated liquid herein refers to a working liquid after the hydrogenation reaction.

Wherein:

b-hydrogenation efficiency (g/L);

C—KMnO₄concentration of the solution (mol/L);

V₀—KMnO₄volume of solution (mL);

M—H₂O₂molar mass (g/mol);

v is the volume (mol/L) of the hydrogenation solution.

The hydrogenation evaluations were carried out for samples # 1 to # 5 and # 6, respectively. Taking samples # 1, # 2 and # 4 as typical representatives, the evaluation results are shown in fig. 2, and it can be seen from the above examples that the hydrogenation catalysts (sample # 1, sample # 2 and sample # 4) with hydrophobic silica carrier have higher hydrogenation activity and higher stability than the silica hydrogenation catalyst (sample # 6) under the same content of active component palladium. The main reason is that the organic groups of the carrier of the silicon oxide bonded with the organic functional groups are increased, so that polar substances such as water and the like in the working solution are difficult to contact with the active component Pd of the catalyst, thereby inhibiting the hydration of the hydrogenation catalyst and improving the stability. In addition, the polarity of the anthrahydroquinone after the hydrogenation of the anthraquinone is higher, and the polarity of the surface of the hydrogenation catalyst bonded with the organic functional group is reduced, so that the anthrahydroquinone as the hydrogenated intermediate species is easy to desorb from the surface of the catalyst, the selectivity of the hydrogenation of the anthraquinone is improved, and the stability of the hydrogenation catalyst of the anthraquinone is improved.

However, as for the results of # 1, # 2 and # 4, it was found that the hydrogenation activity of # 4 and # 1 is higher than that of # 2, and the groups of # 1 sample and # 2 are the same, except that the treatment manner of the silica precursor is different, and the thermogravimetric characterization of # 1 shows that the number of the organic groups contained in # 1 is higher than that of # 2 sample, so it can be seen from the thermogravimetric data of # 1 and # 2 and the evaluation results of the later period that the silica treated with hydrofluoric acid can expose more hydroxyl groups, thereby improving the hydrophobicity of the carrier and further improving the activity and stability of the part. However, compared to samples # 1 and # 4, only the organic groups used were different, with phenyl group used for # 4 and methyl group used for # 1, it can also be shown from thermogravimetric characterization of # 1 and # 4 that the groups in sample # 4 are larger than those in sample # 1. On the basis of the same silica pretreatment, it is reasonable to judge that the 4# sample has higher hydrophobicity than the 1# sample due to the phenyl group adopted, which is also the reason that the activity of the 4# sample is higher than that of the 1# sample, however, the improvement degree of the 4# sample is not very obvious compared with the 1# sample, so when the hydrophobicity of the carrier reaches a certain degree, the hydrophobicity is continuously improved, and the influence of the activity and stability of the hydrogenation catalyst is not very large.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. a preparation method of a hydrophobic noble metal hydrogenation catalyst, is characterized in that, comprises the following steps at least:

a) obtaining the modified precursor A of the silica carrier;

b) bonding and reacting the silica-modified precursor A and the silanizing agent in a solvent to obtain a silica-modified carrier B;

c) supporting the precursor containing the noble metal active element on the modified silica carrier B, and calcining to obtain the precursor C in the oxidized state;

d) reducing the oxidation state precursor C to obtain the hydrophobic noble metal hydrogenation catalyst.

2. method according to claim 1, is characterized in that, step a) is to obtain the modified precursor A of silica carrier by treating silica by alkaline or acid solution;

Preferably, the particle size of the silica is 20-300 μm, the average pore diameter is 10-30 nm, the pore volume is less than 0.75 cc/g, and the specific surface area is 140-180 m ² /g.

3. The method according to claim 2, wherein the alkaline solution is selected from at least one of inorganic alkaline solution and organic alkaline solution;

Preferably, the inorganic alkali solution is selected from at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia solution;

Preferably, the organic base solution is selected from at least one of tetramethylammonium hydroxide solution, tetraethylammonium hydroxide solution, ethanolamine, diethanolamine, and triethanolamine solution;

Preferably, the pH value of the alkaline solution is controlled between 9 and 11.5;

Preferably, the mass ratio of the silica to the mass of the alkaline solution is 1:5˜1:15.

4. method according to claim 2, is characterized in that, described acid solution is selected from at least one in hydrofluoric acid solution, hydrochloric acid solution, sulfuric acid solution;

Preferably, the pH value of the acidic solution is controlled between 2 and 4;

Preferably, the mass ratio of the silica to the mass of the acidic solution is 1:3˜1:15.

5 . The method according to claim 2 , wherein the treatment temperature is between 40 and 95° C.; and the treatment time is between 6 and 96 hr. 6 .

6. The method according to claim 1, wherein in step b), the silylating agent is selected from the group consisting of methyltrimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, and methyltrimethoxysilane. at least one of triethoxysilane, perfluorooctyltriethoxysilane, vinyltrimethoxysilane, and phenyltrimethoxysilane;

Preferably, in step b), the solvent is selected from at least one of toluene, ethylbenzene, xylene, chloroform, anhydrous ethanol, anhydrous methanol, and anhydrous isopropanol;

Preferably, in step b), the ratio of the moles of the silylation reagent to the total surface area of the silica modified precursor A is about 1 to ^{10:10 −6} ;

Preferably, in step b), the bonding reaction temperature is 90˜150° C., and the bonding reaction time is 6˜24 hr.

7. The method according to claim 1, wherein, in step c), the precursor containing noble metal active element is a salt compound containing noble metal active element;

Preferably, the salt compound containing noble metal active element is selected from platinum acetate, platinum propionate, palladium(II) acetate, palladium(II) propionate, palladium(II) 2-methylpropionate, trimethylacetic acid at least one of palladium;

Preferably, in step c), the roasting conditions are: the roasting temperature is 200-350° C., and the roasting time is 1-5 h.

8 . The method according to claim 1 , wherein, in step d), the reduction conditions are as follows: the reduction atmosphere is hydrogen, the reduction temperature is 80-100° C., and the reduction time is 5-6 h. 9 .

9 . The hydrophobic noble metal hydrogenation catalyst prepared by the preparation method according to any one of claims 1 to 8 , wherein the mass content of the noble metal active component in the noble metal catalyst is 0.01 to 2.00 wt % ; Wherein, the content of the active component is calculated by the content of the active element.

10. A method for preparing hydrogen peroxide by catalytic hydrogenation of anthraquinone, characterized in that, reacting a reaction solution containing an anthraquinone raw material in a slurry bed containing a catalyst to obtain hydrogen peroxide;

The catalyst contains the hydrophobic noble metal hydrogenation catalyst of claim 9;

Preferably, the anthraquinone is selected from at least one of ethylanthraquinone, amylanthraquinone, ethyltetrahydroanthraquinone, and amyltetrahydroanthraquinone;

Preferably, the reaction conditions are: the reaction temperature is 40-60° C., the pressure is 0.05-0.3 MPa, and the liquid space velocity is 60-300 h ⁻¹ ;

Preferably, the reaction conditions are: the reaction temperature is 40-50° C., the pressure is 0.01-0.1 MPa, and the liquid space velocity is 60-200 h ⁻¹ .