Catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation and preparation method and application thereof

文档序号：1912237 发布日期：2021-12-03 浏览：16次中文

阅读说明：本技术 用于蒽醌加氢制备双氧水的催化剂及其制备方法与应用 (Catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation and preparation method and application thereof ) 是由骆广生王凯申春张议文郭同新王飞于 2021-09-30 设计创作，主要内容包括：本发明涉及一种用于蒽醌加氢制备双氧水的催化剂,其由载体、负载于载体上的主活性组分和助催化剂构成；所述载体包括氧化铝和/或二氧化硅,所述主活性组分为金属钯；其中,所述载体上还负载有助催化剂,所述助催化剂包括二氧化铈、二氧化钛和二氧化锆中的一种或几种。该催化剂具有介孔结构,比表面积、孔径较大,对氢气分子吸附性能优越,此外金属钯负载量大大降低为0.1wt％-0.5wt％。将该催化剂用于催化2-乙基蒽醌与氢气选择性加氢反应制备双氧水,催化活性优异、选择性高,稳定性强,有良好的再生周期,为蒽醌加氢制备双氧水的工业化生产奠定坚实的基础。(The invention relates to a catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation, which consists of a carrier, a main active component loaded on the carrier and a cocatalyst; the carrier comprises alumina and/or silicon dioxide, and the main active component is metal palladium; wherein, the carrier is also loaded with a cocatalyst which comprises one or more of cerium dioxide, titanium dioxide and zirconium dioxide. The catalyst has a mesoporous structure, large specific surface area and pore diameter, and excellent adsorption performance on hydrogen molecules, and the loading capacity of metal palladium is greatly reduced to 0.1-0.5 wt%. The catalyst is used for catalyzing selective hydrogenation reaction of 2-ethyl anthraquinone and hydrogen to prepare hydrogen peroxide, has excellent catalytic activity, high selectivity, strong stability and good regeneration period, and lays a solid foundation for industrial production of hydrogen peroxide prepared by anthraquinone hydrogenation.)

1. A catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation comprises a carrier, a main active component loaded on the carrier and a cocatalyst; the carrier comprises alumina and/or silicon dioxide, and the main active component is metal palladium; wherein, the carrier is also loaded with a cocatalyst which comprises one or more of cerium dioxide, titanium dioxide and zirconium dioxide.

2. The catalyst according to claim 1, wherein the loading amount of the main active component in the catalyst is 0.01-3 wt%, and the mass ratio of the cocatalyst to the carrier in the catalyst is 0.5-10%.

3. A method for preparing the catalyst of claim 1 or 2, comprising:

a, dissolving a compound containing metal palladium in a solvent I, and uniformly stirring to form a metal palladium compound solution;

step B, adding the carrier into a metal palladium compound solution to form a carrier-metal palladium mixed solution;

step C, heating and stirring the carrier-metal palladium mixed solution under a sealed condition, completely evaporating the first solvent under a non-sealed condition, and drying to obtain a solid containing metal palladium;

step D, dissolving the cocatalyst in the solvent II, and uniformly stirring to form cocatalyst dispersion liquid;

step E, adding a solid containing metal palladium into the promoter dispersion liquid to form a catalyst precursor mixed liquid;

step F, heating and stirring the mixed solution of the catalyst precursor under a sealed condition, completely evaporating the solvent II under a non-sealed condition, and drying to obtain the catalyst precursor;

and G, roasting the catalyst precursor, and then reducing to obtain a catalyst finished product.

4. The method according to claim 3, characterized in that: the first solvent and the second solvent are respectively and independently water and/or ethanol; the first solvent and the second solvent are the same or different, preferably the same; and/or the metal palladium compound comprises one or more of palladium chloride, palladium nitrate, palladium bromide and palladium acetate.

5. The production method according to claim 3 or 4, characterized in that: the supported alumina comprises delta-Al₂O₃、γ-Al₂O₃、α-Al₂O₃And theta-Al₂O₃One or more of the above; and/or the shape of the carrier comprises one or more of a sphere, a strip and a clover.

6. The production method according to any one of claims 3 to 5, characterized in that the mass ratio of the metallic palladium to the promoter in the catalyst precursor mixed solution is (0.1-5):1, preferably (0.5-2): 1.

7. The production method according to any one of claims 3 to 6, characterized in that: in step C and step F, the temperature of heating is 50-90 ℃, preferably 65-80 ℃; and/or the stirring time is 1-5h, preferably 2-3 h; and/or the temperature of the drying is 100 ℃.

8. Use of the catalyst of claim 1 or 2 or the catalyst prepared by the process of any one of claims 3 to 7 in the preparation of hydrogen peroxide by hydrogenation of anthraquinone; preferably, the application comprises the steps of filling hydrogen into reactant feed liquid containing the catalyst, the 2-ethyl anthraquinone and the reaction solvent, carrying out hydrogenation reaction, and then preparing hydrogen peroxide through oxidation and extraction.

9. The use according to claim 8, wherein the content of the 2-ethyl anthraquinone in the reactant feed liquid is more than or equal to 90g/L, preferably 110 g/L; and/or the mass ratio of the catalyst to the 2-ethyl anthraquinone is (0.01-1) to 5, preferably (0.05-0.3) to 2; and/or the pressure of filling hydrogen is 0.1-2MPa, preferably 0.5-1 MPa; and/or the reaction solvent comprises one or more of 1,3, 5-trimethylbenzene, 1,2, 4-trimethylbenzene and trioctyl phosphate.

10. Use according to claim 9 or 10, characterized in that the hydrogenation reaction temperature is 20-100 ℃, preferably 30-80 ℃; and/or the time of the hydrogenation reaction is 0.5 to 5 hours, preferably 1 to 3 hours.

Technical Field

The invention belongs to the technical field of organic catalysts, relates to a catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation and a preparation method and application thereof, and particularly relates to a preparation method and application of a palladium-based catalyst for preparing hydrogen peroxide by catalyzing 2-ethyl anthraquinone to react with hydrogen.

Background

Hydrogen peroxide (H)₂O₂) Is widely applied to almost all industrial fields, in particular to the fields of chemical industry and environmental protection. Because the only degradation product is water, the method plays a great environmental-friendly role in the chemical industry.

With the increasing demand of hydrogen peroxide, by 2019, China H₂O₂The production capacity of manufacturers exceeds more than seventy families, and the domestic production capacity is about 370 ten thousand tons per year, which accounts for more than half of the total production capacity of the whole world. From the current situation that the requirement for environmental protection is increasingly enhanced at present, H₂O₂As a green oxidant, it is necessary to replace the conventional high energy-consuming oxidant, and the demand will increase year by year in the future.

The preparation method of hydrogen peroxide mainly comprises an anthraquinone method, an isopropanol method, an electrolysis method, an oxygen cathode reduction method, an oxygen and water synthesis method, a direct hydrogen and oxygen synthesis method and the like. But the anthraquinone method has the advantages of low energy consumption, low cost, easy scale-up production of devices and the like, which account for more than 95 percent of all the preparation methods at present. The anthraquinone process mainly uses Anthraquinone (AQ) as working carrier, and mainly includes hydrogenation of anthraquinone, hydrogenated Anthraquinone (AQH)₂) Oxidizing and post-extracting to obtain H₂O₂And the like. In which the hydrogenation of anthraquinone is the key of anthraquinone process, therefore, it is necessary to prepare high-activity and high-selectivity catalyst to enhance selective hydrogenation performance of anthraquinoneIncrease H₂O₂The yield is reduced, the production cost is reduced, and the working solution circulation efficiency is increased to improve the economic benefit of the anthraquinone hydrogenation process.

The catalysts for hydrogenation of anthraquinone are mainly divided into two types, namely nickel-based catalysts and palladium-based catalysts. The nickel-based catalyst has been gradually replaced by palladium-based catalyst due to its harsh reaction conditions and easy deactivation. For palladium-based catalysts, the selectivity and stability of anthraquinone reaction system catalysts are the focus problems which need to be solved at present. The current research on catalyst improvement aiming at the phenomenon is mainly divided into two directions: modification of the carrier and optimization of the active component loading metal. The carrier modification aspect is mainly realized by regulating and controlling the pH value, the adsorption performance and the pore structure of the carrier. Carrier Al was investigated₂O₃Or SiO₂Modifying, adding Na₂SiO₃Or alkali metal ions such as: li, Na, K, Cs and the like reduce the deep hydrogenation of the reaction by enhancing the interaction of anthraquinone molecules and carriers, thereby enhancing the selectivity; also, researchers have utilized Al by modifying the surface properties and pore structure of alumina₂O₃The excellent dispersion property of metal Pd and lower diffusion resistance to improve the reaction activity and stability. The active ingredient research aspect is mainly to adjust the form and the composition of the active ingredient. There are researchers controlling the reactivity by controlling the exposed surface of the metallic palladium crystals, and also enhancing the reactivity by intermetallic interactions through bimetallic loading. Bimetallic studies have been reported as follows: Pd-Ru, Pd-Au, Pd-Rh, Pd-Ir, Pt-Au, Pd-Co, Pd-Cu, Pd-Ag, etc. The existing catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation has the problems of unstable structure, incapability of recycling, poor catalytic activity and selectivity, large loading capacity of metal palladium of the catalyst, high cost and the like.

Therefore, the problem at present is to research and develop a catalyst for preparing hydrogen peroxide by hydrogenation of anthraquinone, which has high catalytic activity and selectivity, stable structure, reusability and low cost.

Disclosure of Invention

Technical problem to be solved by the inventionAiming at the defects of the prior art, the invention provides a catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation and a preparation method and application thereof. The catalyst is used for catalyzing the addition reaction of 2-ethyl anthraquinone and hydrogen, and then H is prepared by oxidation extraction₂O₂The catalyst has excellent catalytic activity, high selectivity, high stability and good regeneration period, and greatly reduces the consumption of metal palladium.

Therefore, the invention provides a catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation, which consists of a carrier, a main active component loaded on the carrier and a cocatalyst; the carrier comprises alumina and/or silicon dioxide, and the main active component is metal palladium; wherein, the carrier is also loaded with a cocatalyst which comprises one or more of cerium dioxide, titanium dioxide and zirconium dioxide.

In some embodiments of the invention, the loading of the main active component in the catalyst is 0.01 wt% to 3 wt%, and the mass ratio of the cocatalyst to the carrier in the catalyst is 0.5 to 10%.

In a second aspect, the present invention provides a method for preparing the catalyst of the first aspect, comprising:

a, dissolving a compound containing metal palladium in a solvent I, and uniformly stirring to form a metal palladium compound solution;

step B, adding the carrier into a metal palladium compound solution to form a carrier-metal palladium mixed solution;

step D, dissolving the cocatalyst in the solvent II, and uniformly stirring to form cocatalyst dispersion liquid;

step E, adding a solid containing metal palladium into the promoter dispersion liquid to form a catalyst precursor mixed liquid;

and G, roasting the catalyst precursor, and then reducing to obtain a catalyst finished product.

In the invention, the first solvent and the second solvent are respectively and independently water and/or ethanol; the first solvent and the second solvent may be the same or different, and are preferably the same.

In some embodiments of the invention, the metallic palladium compound comprises one or more of palladium chloride, palladium nitrate, palladium bromide, and palladium acetate.

In the present invention, the carrier alumina comprises delta-Al₂O₃、γ-Al₂O₃、α-Al₂O₃And theta-Al₂O₃One or more of them.

In the invention, the shape of the carrier comprises one or more of a sphere, a strip and a clover.

In some embodiments of the present invention, the mass ratio of the metal palladium to the promoter in the catalyst precursor mixed solution is (0.1-5):1, preferably (0.5-2): 1.

According to the process of the invention, the temperature of the heating in step C and step F is between 50 and 90 ℃ and preferably between 65 and 80 ℃.

In some embodiments of the invention, in step C and step F, the stirring time is 1 to 5 hours, preferably 2 to 3 hours.

In some preferred embodiments of the present invention, the temperature of the drying is 100 ℃ in step C and step F.

In a third aspect, the present invention provides the use of a catalyst according to the first aspect of the present invention or a catalyst prepared by a process according to the second aspect of the present invention in the hydrogenation of anthraquinones to produce hydrogen peroxide.

According to the invention, the application comprises the steps of filling hydrogen into reactant feed liquid containing the catalyst, 2-ethyl anthraquinone and reaction solvent, carrying out hydrogenation reaction, and then preparing hydrogen peroxide through oxidation and extraction.

In some embodiments of the present invention, the content of the 2-ethyl anthraquinone in the reactant solution is greater than or equal to 90g/L, preferably 110 g/L.

In some embodiments of the invention, the catalyst to 2-ethylanthraquinone mass ratio is (0.01-1):5, preferably (0.05-0.3): 2.

In some embodiments of the invention, the pressure of the hydrogen charge is in the range of 0.1 to 2MPa, preferably 0.5 to 1 MPa.

In some embodiments of the invention, the reaction solvent comprises one or more of 1,3, 5-trimethylbenzene, 1,2, 4-trimethylbenzene, and trioctyl phosphate.

According to the invention, the hydrogenation reaction temperature is 20 to 100 ℃, preferably 30 to 80 ℃.

In some embodiments of the invention, the hydrogenation reaction time is from 0.5 to 5 hours, preferably from 1 to 3 hours.

A catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation comprises a carrier, a main active component loaded on the carrier and a cocatalyst; the carrier comprises alumina and/or silicon dioxide, and the main active component is metal palladium; wherein, the carrier is also loaded with a cocatalyst which comprises one or more of cerium dioxide, titanium dioxide and zirconium dioxide

The catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation is prepared by taking alumina or silicon dioxide as a carrier, has a mesoporous structure, and is loaded with main catalyst metal palladium and cocatalyst cerium dioxide, titanium dioxide, zirconium dioxide and the like. The catalyst is used for catalyzing the addition reaction of 2-ethyl anthraquinone and hydrogen, and then H is prepared by oxidation extraction₂O₂The catalyst has excellent catalytic activity, high selectivity, strong stability and good regeneration period, greatly reduces the consumption of metal palladium and lays a solid foundation for the industrial production of preparing hydrogen peroxide by anthraquinone hydrogenation.

Drawings

The invention is described in further detail below with reference to the attached drawing figures:

FIG. 1 shows the reaction process of 2-ethyl anthraquinone and hydrogen gas to prepare hydrogen peroxide.

Detailed Description

In order that the invention may be readily understood, a more particular description of the invention briefly described below will be rendered by reference to specific embodiments that are illustrated in the appended drawings. However, before the invention is described in detail, it is to be understood that this invention is not limited to particular embodiments described. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

Where a range of values is provided, it is understood that each intervening value, to the extent that there is no stated or intervening value in that stated range, to the extent that there is no such intervening value, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where a specified range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described.

Term of

The term "water" as used herein means deionized water, distilled water or ultrapure water unless otherwise specified or limited.

The terms "about," "substantially," and "primarily," when used in conjunction with a range of elements, concentrations, temperatures, or other physical or chemical properties or characteristics, as described herein, cover variations that may exist in the upper and/or lower limits of the range for the property or characteristic, including variations due to, for example, rounding, measurement, or other statistical variations. For example, as used herein, numerical values associated with amounts, weights, and the like, are defined as all numbers per particular value plus or minus 1%, e.g., the term "about 10%" should be interpreted as "9% to 11%".

II, embodiments

FIG. 1 showsThe reaction process of preparing hydrogen peroxide by the addition reaction of 2-ethyl anthraquinone and hydrogen is disclosed. Hydrogen and C ═ O in 2-ethyl anthraquinone are subjected to selective hydrogenation reaction to generate diethyl hydroanthraquinone, and the diethyl hydroanthraquinone is subjected to oxygen oxidation, working solution extraction and the like to obtain hydrogen peroxide. The main side reactions are: excessive addition reaction of diethyl hydroanthraquinone with hydrogen to produce H through addition reaction with benzene ring in hydroanthraquinone₈eAQH₂EAN, etant, etc. cannot generate hydrogen peroxide by oxidation. The generation of the by-product not only reduces the yield of the hydrogen peroxide, but also greatly reduces the cycle efficiency of the working solution. In addition, the main problems of inhibiting the reaction of anthraquinone hydrogenation to generate hydrogen peroxide are high metal loading, low dispersity and few active sites. Therefore, in general, the catalyst is required to have enhanced metal dispersion, increased number of active sites in the catalyst, and improved H₂The adsorption performance of the molecule is improved, the adsorption of C ═ O in anthraquinone molecules is improved, the adsorption of the C ═ O on benzene rings is reduced, and the problems of low catalyst activity and more byproducts are solved. Therefore, the catalyst is required to have larger pore diameter, larger specific surface area, stronger adsorption performance to anthraquinone molecules, low metal loading and high dispersion degree.

Based on the characteristics of serious side reaction and metal agglomeration phenomenon and low hydrogenation activity of the system, the existing reported catalyst has the following problems: the selectivity is much lower than 80%, and serious excessive hydrogenation side reaction exists; the problem of metal agglomeration is serious, and the activity of the catalyst is obviously reduced in a short time. Based on the characteristics of main reaction and side reaction, the catalyst is designed to meet the requirements of high hydrogen peroxide selectivity and weak excessive hydrogenation side reaction, and meet the requirements of difficult metal agglomeration, high dispersity and inactivation resistance. A great deal of experimental research is carried out on the catalyst and the synthesis process for preparing hydrogen peroxide by 2-ethyl anthraquinone and hydrogen.

The inventor researches and discovers that the synergistic action of metal sites and a carrier oxide is needed to efficiently convert 2-ethylanthraquinone and hydrogen and prepare hydrogen peroxide with high selectivity. The main active component of palladium metal is needed to catalyze the hydrogenation reaction of anthraquinone, and the cocatalyst is needed to assist in enhancing the metal dispersibility and improving H₂Adsorption propertyCan reduce side reaction. Secondly, the mesoporous catalyst has natural advantages superior to microporous molecular sieves, and the excellent mass transfer performance and adsorption performance reduce the metal agglomeration phenomenon of the mesoporous catalyst, so that the mesoporous catalyst has stronger stability and is more resistant to inactivation.

The inventor further researches and develops a catalyst with industrial application prospect, which not only ensures the high selectivity of the hydrogen peroxide, but also has long service life and good cycle performance. The catalyst comprises the components of taking metal palladium as a main active component and adding cerium oxide, titanium oxide or zirconium oxide as a cocatalyst. The preparation method of the catalyst comprises the steps of dissolving a compound of metal palladium in water to form a palladium aqueous solution; adding carrier alumina or silicon dioxide into the solution, stirring in water bath, evaporating for crystallization, drying the crystallized precursor, and loading the cocatalyst (cerium dioxide, titanium dioxide or zirconium oxide) by the same method. And after the loading is finished, drying, roasting and reducing the solid by hydrogen to obtain a catalyst finished product with a corresponding structure.

The characterization shows that the catalyst contains abundant mesopores, has abundant oxygen vacancies, is high in metal dispersity, and is in a state of coexistence of metal monoatomic metal and nanoparticles, wherein the monoatomic metal accounts for the main part. And the metal dispersity and the oxygen vacancy content of the catalyst are adjustable. The hydrogen peroxide is prepared by catalyzing the selective hydrogenation reaction of 2-ethyl anthraquinone, and the discovery shows that for the added catalyst promoter cerium dioxide, when the ratio of the catalyst promoter to the main active component metal palladium is about 3, the catalyst has high activity, low metal loading capacity, good dispersion performance and high oxygen vacancy content, and the selectivity of active quinone reaches 99 percent and is far higher than the level reported in the literature. The present invention has been made based on this finding.

Therefore, the invention relates to a catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation, which consists of a carrier, a main active component loaded on the carrier and a cocatalyst; the carrier comprises alumina and/or silica, preferably alumina or silica, and the main active component is metal palladium; wherein, the carrier is also loaded with a cocatalyst which comprises one or more of cerium dioxide, titanium dioxide and zirconium dioxide.

In some specific examples, the catalyst is prepared by using alumina or silica as a carrier, and has a mesoporous structure, wherein the carrier is loaded with main catalyst metal palladium and promoters cerium dioxide, titanium dioxide, zirconium dioxide and the like. In the catalyst, the loading amount of the main active component is 0.01-3 wt%, and the mass ratio of the cocatalyst to the carrier in the catalyst is 0.5-10%.

The second aspect of the invention relates to a preparation method of the catalyst for preparing hydrogen peroxide by anthraquinone hydrogenation, which comprises the following specific processes:

a, dissolving a compound containing metal palladium in a solvent I, and stirring for 10min at normal temperature to form a uniform metal palladium compound solution;

step B, adding a carrier (alumina or silicon dioxide) into a metal palladium compound solution to form a carrier-metal palladium mixed solution;

step C, heating and stirring the carrier-metal palladium mixed solution in a water bath under the sealing condition of the preservative film, opening the preservative film to completely evaporate the solvent I, and drying at 100 ℃ to obtain a solid containing metal palladium;

step D, dissolving the cocatalyst in the solvent II, and stirring for 10min at normal temperature to form uniform cocatalyst dispersion liquid;

step E, adding a solid containing metal palladium into the promoter dispersion liquid to form a catalyst precursor mixed liquid;

step F, heating and stirring the mixed solution of the catalyst precursor in a water bath under the sealing condition of the preservative film, opening the preservative film to completely evaporate the solvent II, and drying at 100 ℃ to obtain a catalyst precursor;

and G, roasting the catalyst precursor at 300 ℃, and then reducing at 400 ℃ to obtain a catalyst finished product.

In some embodiments of the invention, the metallic palladium compound comprises one or more of palladium chloride, palladium nitrate, palladium bromide, and palladium acetate.

In the present invention, the carrier alumina comprises delta-Al₂O₃、γ-Al₂O₃、α-Al₂O₃And theta-Al₂O₃That is, the alumina may be delta-Al₂O₃、γ-Al₂O₃、α-Al₂O₃And theta-Al₂O₃Any one crystal form or a mixed crystal form of two or more kinds thereof, wherein γ -Al is preferable₂O₃Crystal form, relative to other crystal forms, gamma-Al₂O₃The crystal form has stronger molecular adsorption performance and better stability.

In the invention, the shape of the carrier comprises one or more of a sphere, a strip and a clover.

Researches find that the number of oxygen vacancies and the metal dispersity can be adjusted by adjusting the ratio of the metal palladium to the cocatalyst, and the catalyst has different mesoporous structures, so that the optimal ratio of high hydrogen peroxide content and low hydrogenation byproducts is found. In some embodiments of the present invention, the mass ratio of the metallic palladium to the promoter (ceria, titania or zirconia) in the catalyst precursor mixed solution is (0.1-5):1, preferably (0.5-2): 1.

According to the process of the invention, the temperature of the heating in step C and step F is between 50 and 90 ℃ and preferably between 65 and 80 ℃.

In some embodiments of the invention, in step C and step F, the stirring time is 1 to 5 hours, preferably 2 to 3 hours, so that it has enough time to crystallize to form a stable structure.

It will be understood that in the above-mentioned preparation of the catalyst for the hydrogenation of anthraquinones, the steps A to C are carried out by supporting metallic palladium on a carrier to obtain a solid containing metallic palladium, and the steps D to E are carried out by supporting the promoter on the solid containing metallic palladium in the same manner as described above.

As described above, the catalysts for hydrogenation of anthraquinones are mainly classified into two types, a nickel-based catalyst and a palladium-based catalyst. Except for the existing method for preparing the catalyst, the research on adding the auxiliary agent oxide on the basis of the main active component is very few, and no report is made on an anthraquinone hydrogenation system by using cerium oxide, titanium oxide or zirconium oxide as the auxiliary catalyst. The metal oxide is firstly loaded in the carrier, and the strong interaction of the metal oxide and the main active component can be improved by adjusting the interface geometrical structure and the electronic structure. The method greatly improves the stability of the catalyst by controlling the growth of metal particles and improving the electronic properties of metal nano particles and carriers.

The invention optimizes the addition of the cocatalyst (cerium dioxide, titanium oxide or zirconium oxide) aiming at the problems of the existing catalyst, and compared with the reported catalyst, the catalyst has the following advantages: 1) the catalyst structure is stable, can be recycled, and no decrease in activity is observed over 20 cycles. 2) The catalyst improves the catalyst pair H by adjusting the proportion of the cocatalyst to the metal palladium₂The adsorption performance of molecules, the oxygen vacancy concentration in the carrier is enhanced, and excellent activity and selectivity can be realized, wherein the activity and the selectivity can respectively reach more than 98 percent and are far higher than the level reported by the literature; 3) the catalyst contains rich mesopores, has excellent mass transfer performance, and can be used for a fixed bed reactor and a kettle reactor device; 4) the catalyst greatly reduces the loading of metal palladium, and the actual loading is lower than 0.1 wt%, which is far lower than the level reported in the current literature.

The application of the third aspect of the invention can be understood as a method for preparing hydrogen peroxide by an anthraquinone method. The reaction is that 2-ethyl anthraquinone reacts with hydrogen to generate hydrogen anthraquinone under the action of a catalyst, and hydrogen peroxide is obtained by oxidation and extraction. Specifically, hydrogen is charged into a reactant feed liquid containing the catalyst, 2-ethylanthraquinone and an optional solvent to prepare the diethylhydroanthraquinone, wherein the solid catalyst is the catalyst according to the first aspect of the present invention or the catalyst prepared by the method according to the second aspect of the present invention.

According to the invention, the content of the 2-ethyl anthraquinone in the reactant liquid is more than or equal to 90g/L, preferably 110 g/L; the mass ratio of the catalyst to the 2-ethyl anthraquinone is (0.01-1): 5; the mass ratio of the catalyst to the 2-ethyl anthraquinone is (0.01-1) to 5, preferably (0.05-0.3) to 2; the pressure of the hydrogen gas is 0.1 to 2MPa, preferably 0.5 to 1 MPa.

In the invention, the reaction solvent comprises one or more of 1,3, 5-trimethylbenzene, 1,2, 4-trimethylbenzene and trioctyl phosphate.

In some embodiments of the invention, the temperature of the hydrogenation reaction is in the range of 20 to 100 ℃, preferably 30 to 80 ℃.

In other embodiments of the present invention, the hydrogenation reaction time is 0.5 to 5 hours, preferably 1 to 3 hours.

The catalyst with adjustable oxygen vacancy and metal dispersity is prepared by adjusting the adding proportion of a cocatalyst (cerium dioxide, titanium oxide or zirconium oxide) and a main active component metal palladium. The inventor finds that the catalyst has higher oxygen vacancy content, and for a catalyst promoter cerium dioxide, when the ratio of the catalyst promoter to a main active component palladium is about 3, the catalyst has high activity, low metal loading capacity, good dispersion performance and high oxygen vacancy content, and the selectivity of active quinone reaches 99 percent and is far higher than the level reported by the literature; the inherent mesoporous structure has excellent mass transfer performance, difficult inactivation and long service life; the catalyst has no activity loss in 20 cycles, which shows that the catalyst has excellent stability.

The catalyst provided by the invention has the advantages of simple preparation process, low cost and easy scale-up. And the property of the catalyst can realize the fine regulation and control of the metal dispersion degree and the oxygen vacancy of the catalyst by adjusting the addition amount of the cocatalyst, and the catalyst is used for catalyzing the reaction of 2-ethylanthraquinone and hydrogen to prepare hydrogen peroxide, shows excellent catalytic activity, selectivity and stability, and lays a solid foundation for the industrial production of preparing hydrogen peroxide by an anthraquinone method.

Examples

The present invention will be specifically described below with reference to specific examples. The experimental methods described below are, unless otherwise specified, all routine laboratory procedures. The experimental materials described below, unless otherwise specified, are commercially available.

The components of the reaction liquid are quantified by liquid chromatography, an internal standard method is adopted, and an internal standard substance is p-nitrophenol. The conversion rate of 2-ethyl anthraquinone, selectivity and yield of active quinone are defined as shown in formulas (I), (II) and (III).

In formula (I):

n_0EAQis the amount of the added 2-ethyl anthraquinone initial substance, and the unit is mol;

n_convertedEAQthe amount of the converted 2-ethyl anthraquinone substance after the oxidation reaction is finished is detected by using an internal standard substance and is measured in mol.

In the formula (II):

n₀is the amount of the added 2-ethyl anthraquinone initial substance, and the unit is mol;

n_1EAQthe amount of 2-ethyl anthraquinone substances after the reaction oxidation is finished is detected by using an internal standard substance and is measured in mol.

n_H4EAQThe amount of the generated tetrahydro-2-ethylanthraquinone after the reaction is finished is detected by using an internal standard substance and is measured in mol.

In the formula (III):

n₀is the amount of the added 2-ethyl anthraquinone initial substance, and the unit is mol;

n_H2O2the amount of the generated hydrogen peroxide after the reaction is finished is detected by using an internal standard substance, and the unit is mol.

Example 1:

(1) dissolving 0.07g of metal palladium compound in water, and stirring for 10min at normal temperature to obtain a uniformly dispersed solution;

(2) 12g of gamma-Al₂O₃Adding into the above solution;

(3) and (3) heating and stirring the obtained mixed solution preservative film in a water bath for a period of time under a sealed condition, opening the preservative film to fully crystallize and evaporate the preservative film, and drying the preservative film at 100 ℃. And loading the solid obtained after drying with a cocatalyst cerium oxide by the same method, drying under the same conditions, roasting at 300 ℃, and reducing at 400 ℃ to obtain a catalyst finished product. The characterization shows that the catalyst is in a mesoporous structure, wherein the addition ratio of the actual cocatalyst to the main active component is detected to be 3.

(4) 0.05g of the solid catalyst, 2g of 2-ethyl anthraquinone, 20mL of a mixture of trimethylbenzene and trioctyl phosphate and 0.3g of an internal standard substance p-nitrophenol are added into a 100mL reaction kettle, 0.4MPa of hydrogen is filled, the temperature is heated to 60 ℃, and the reaction is carried out for 30min, so as to obtain the 2-ethyl hydrogen anthraquinone. Hydrogen peroxide is obtained by oxidation and extraction. The conversion of 2-ethylanthraquinone is determined by tests and calculations based on the formulae (I), (II) and (III)>99% active quinone selectivity of 97%, H₂O₂The yield reaches 98 percent.

Example 2: