Method for catalytically decomposing hydrogen peroxide in methanol aqueous solution

Abstract

The invention relates to the field of hydrogen peroxide decomposition, and discloses a method for catalytically decomposing hydrogen peroxide in a methanol aqueous solution. The invention relates to a method for catalytically decomposing hydrogen peroxide in a methanol aqueous solution, which comprises the following steps: in the presence of a catalyst, carrying out decomposition reaction on the methanol aqueous solution containing hydrogen peroxide under the conditions that the temperature is 30-100 DEG C; wherein the catalyst comprises a titanium silicalite molecular sieve with an MFI topological structure and aluminum oxide; on the basis of the total amount of the catalyst, the content of the titanium silicalite molecular sieve with the MFI topological structure is 40-90% by mass, and the content of the aluminum oxide is 10-60% by mass; and the side pressure crushing strength of the catalyst is 70-150N / cm. According to the method, a catalyst containing a titanium silicalite molecular sieve with an MFI topological structure and aluminum oxide is selected, the mass fraction of hydrogen peroxide can be reduced, meanwhile, a large amount of loss of active components is avoided in the long-period operation process, and the decomposition activity is kept stable.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen peroxide decomposition, and in particular to a method for catalytically decomposing hydrogen peroxide in a methanol aqueous solution. Background Art

[0002] Epichlorohydrin is an important basic organic chemical raw material and intermediate, widely used in the synthesis of epoxy resins, epichlorohydrin rubber, medicines, pesticides, surfactants, plasticizers and other industrial products.

[0003] Patent application CN101747297A discloses that epichlorohydrin can be synthesized continuously and stably for a long time by epoxidation of 3-chloropropylene with hydrogen peroxide in the presence of titanium silicon molecular sieve catalyst and methanol solvent, with a conversion rate of hydrogen peroxide higher than 97% and a selectivity of epichlorohydrin higher than 95%. However, during long-term operation, the conversion rate of hydrogen peroxide is usually maintained between 97% and 99%, so that the epoxidation reaction product contains 0.05% to 0.5% by mass of hydrogen peroxide.

[0004] Patent application CN106140186A discloses a hydrogen peroxide decomposition catalyst and a method for decomposing hydrogen peroxide in a product of 3-chloropropylene and hydrogen peroxide epoxidation reaction, wherein the catalyst contains 1% to 20% by mass of a metal oxide of Group IVB, 1% to 20% by mass of a metal oxide of Group VIB, 1% to 20% by mass of a metal oxide of Group IB, and 40% to 97% by mass of a metal oxide of Group IIIA, and the decomposition of hydrogen peroxide in the epoxidation reaction product is carried out at a temperature of 0 to 50°C and a pressure of 0.1 to 2.0 MPa, and the decomposition of hydrogen peroxide in the epoxidation reaction product can be reduced to less than 0.02% by mass. However, the patent does not disclose the side pressure crushing strength of the catalyst. Studies have found that the catalyst prepared by the method disclosed in patent application CN106140186A has a side pressure crushing strength of less than 70 N / cm, is easily broken, and is difficult to meet the strength requirements of an industrial fixed bed reactor for loading catalysts.

[0005] Patent application CN114471591A discloses a hydrogen peroxide decomposition catalyst and its application in catalytic decomposition of hydrogen peroxide in methanol aqueous solution. The hydrogen peroxide decomposition catalyst contains a certain amount of IVB group metal oxide, VIB group metal oxide, IB group metal oxide and IIIA group metal oxide. The lateral crushing strength of the hydrogen peroxide decomposition catalyst reaches more than 70N / cm, which can reduce the mass fraction of hydrogen peroxide in methanol aqueous solution to less than 0.02%. However, the patent does not disclose the change of the catalyst component content during the long-term operation of the catalyst. Studies have found that the catalyst prepared by the method disclosed in patent application CN114471591A is prone to the loss of VIB group metal elements (such as chromium, molybdenum, tungsten, etc.) and IB group metal elements (such as copper, etc.) contained in the long-term use process, and it is difficult to meet the requirements of industrial fixed bed reactors for catalyst life. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems in the prior art that the catalyst cannot keep active components from being lost and the mass fraction of hydrogen peroxide after decomposition is low during the decomposition process of hydrogen peroxide, and to provide a method for catalytically decomposing hydrogen peroxide in a methanol aqueous solution. The method uses a catalyst containing a titanium silicon molecular sieve with an MFI topological structure and aluminum oxide, which can reduce the mass fraction of hydrogen peroxide in the reaction raw materials. At the same time, a large amount of component loss is avoided during long-term operation, and the decomposition activity remains stable.

[0007] In order to achieve the above object, the present invention provides a method for catalytically decomposing hydrogen peroxide in a methanol aqueous solution, wherein the method comprises:

[0008] In the presence of a catalyst, a methanol aqueous solution containing hydrogen peroxide is subjected to a decomposition reaction, wherein the conditions of the decomposition reaction include: a temperature of 30-100° C.;

[0009] The catalyst comprises titanium silicon molecular sieve with MFI topology structure and alumina; based on the total amount of the catalyst, the content of the titanium silicon molecular sieve with MFI topology structure is 40-90% by mass, and the content of the alumina is 10-60% by mass; the lateral crushing strength of the catalyst is 70-150N / cm.

[0010] The method provided by the present invention selects a catalyst containing a titanium silicon molecular sieve with an MFI topological structure and aluminum oxide. When used for decomposing hydrogen peroxide, the mass fraction of hydrogen peroxide in a methanol aqueous solution containing hydrogen peroxide can be reduced to below 0.02%, thereby improving the decomposition efficiency of hydrogen peroxide. Moreover, during the operation process of a long period (preferably greater than 200 hours), no significant loss of components in the catalyst is observed, and the decomposition activity remains stable.

[0011] The method provided by the invention can decompose the methanol aqueous solution containing hydrogen peroxide before discharge, effectively eliminates the potential harm of wastewater with high hydrogen peroxide content to the environment, and is environmentally friendly and safe. DETAILED DESCRIPTION

[0012] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0013] The present invention provides a method for catalytically decomposing hydrogen peroxide in a methanol aqueous solution, wherein the method comprises:

[0014] In the presence of a catalyst, a methanol aqueous solution containing hydrogen peroxide is subjected to a decomposition reaction, wherein the conditions of the decomposition reaction include: a temperature of 30-100° C.;

[0015] The catalyst comprises titanium silicon molecular sieve with MFI topology structure and alumina; based on the total amount of the catalyst, the content of the titanium silicon molecular sieve with MFI topology structure is 40-90% by mass, and the content of the alumina is 10-60% by mass; the lateral crushing strength of the catalyst is 70-150N / cm.

[0016] Existing titanium silicon molecular sieves with MFI topology are usually used for epoxidation reactions, which mainly rely on the fact that the main active site of the titanium silicon molecular sieve with MFI topology is isolated tetracoordinated framework titanium, hydrogen peroxide interacts with the isolated tetracoordinated framework titanium to form a Ti-OOH intermediate, and then olefins and Ti-OOH undergo epoxidation to generate related epoxidation products, but there is currently no report on the direct use of titanium silicon molecular sieves for hydrogen peroxide decomposition reactions. The method provided by the present invention selects a catalyst containing titanium silicon molecular sieves with MFI topology and aluminum oxide, and when used to decompose hydrogen peroxide, it can not only improve the decomposition efficiency of hydrogen peroxide, but also reduce the mass fraction of hydrogen peroxide in the methanol aqueous solution containing hydrogen peroxide to less than 0.02%, and during the long-term (preferably more than 200 hours) operation process, no significant loss of components in the catalyst is observed, and the decomposition activity remains stable.

[0017] The method provided by the invention can decompose the methanol aqueous solution containing hydrogen peroxide before discharge, effectively eliminates the potential harm of wastewater with high hydrogen peroxide content to the environment, and is environmentally friendly and safe.

[0018] In the present invention, the lateral crushing strength of the catalyst is measured by using a ZQJ-II intelligent particle strength tester produced by Dalian Intelligent Testing Machine Factory, with reference to the HG / T2782-1996 standard, and the measured lateral crushing strength is the average value of 20 particles.

[0019] In the present invention, the content of each component in the catalyst is measured by inductively coupled plasma (ICP).

[0020] In the present invention, preferably, based on the total amount of the catalyst, the content of the titanium silicon molecular sieve with the MFI topology structure is 50-85% by mass, and the content of the aluminum oxide is 15-50% by mass. The advantage of adopting this preferred embodiment is that the content of the titanium silicon molecular sieve in the catalyst is further increased, thereby improving the decomposition efficiency of hydrogen peroxide.

[0021] In the present invention, preferably, the lateral crushing strength of the catalyst is 75-120 N / cm. The advantage of adopting this preferred embodiment is that the catalyst has high strength, which is convenient for filling and long-term use of the catalyst in industrial devices.

[0022] In the present invention, there is no particular limitation on the source of aluminum oxide, as long as aluminum oxide can be provided. Preferably, the aluminum oxide is provided by aluminum hydroxide powder and / or aluminum sol.

[0023] In the present invention, preferably, the titanium-silicon molar ratio of the titanium-silicon molecular sieve with MFI topology is 1:20-1:100. The advantage of adopting this preferred embodiment is that the titanium species content in the titanium-silicon molecular sieve is relatively high, thereby improving the efficiency of the catalyst in decomposing hydrogen peroxide.

[0024] In the present invention, there is no particular limitation on the shape of the catalyst, and any shape conventionally defined in the art can be adapted to the present invention.

[0025] In the present invention, there is no particular limitation on the preparation method of the catalyst, and the catalyst can be prepared by conventional methods in the art, for example, it can be prepared according to the preparation method of titanium silicon molecular sieve catalyst disclosed in CN102259023A, which will not be described in detail in the present invention.

[0026] In the present invention, the method can be applied to the decomposition of hydrogen peroxide in any methanol aqueous solution containing hydrogen peroxide, and the present invention has no particular limitation on the content of hydrogen peroxide. Preferably, based on the total amount of the methanol aqueous solution containing hydrogen peroxide, the content of hydrogen peroxide in the methanol aqueous solution containing hydrogen peroxide is 0.02-1% by mass, and more preferably 0.05-0.6% by mass.

[0027] In the present invention, the method can be applied to the decomposition of hydrogen peroxide in any methanol aqueous solution containing hydrogen peroxide, and the content of methanol is not particularly limited in the present invention. Preferably, based on the total amount of methanol aqueous solution containing hydrogen peroxide, the content of methanol in the methanol aqueous solution containing hydrogen peroxide is 5-95% by mass, and more preferably 20-80% by mass.

[0028] In the present invention, preferably, the methanol aqueous solution containing hydrogen peroxide may also contain other water-soluble impurities, and the types of water-soluble impurities are not specifically limited in the present invention, for example, 1-chloro-3-methoxy-2-propanol, 3-chloro-1,2-propylene glycol, etc. The content of water-soluble impurities is not particularly limited in the present invention, and preferably, based on the total amount of the methanol aqueous solution containing hydrogen peroxide, the total content of the water-soluble impurities is less than 1% by mass.

[0029] In the present invention, the source of the methanol aqueous solution containing hydrogen peroxide is not particularly limited. Preferably, the methanol aqueous solution containing hydrogen peroxide is provided by at least one of the following: epoxidation reaction of 3-chloropropylene and hydrogen peroxide, epoxidation reaction of propylene and hydrogen peroxide, and production of hydrogen peroxide by anthraquinone method, preferably by epoxidation reaction of 3-chloropropylene and hydrogen peroxide.

[0030] In the present invention, the temperature range for the decomposition reaction is relatively wide. Preferably, the conditions for the decomposition reaction include: a temperature of 40-90°C, for example, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90°C and values ​​between any two groups, more preferably 50-80°C. The use of the catalyst provided by the present invention to catalyze the decomposition of a methanol aqueous solution containing hydrogen peroxide can make the reaction conditions more moderate and improve the industrial production value.

[0031] In the present invention, the pressure range for the decomposition reaction is relatively wide. Preferably, the conditions for the decomposition reaction include: a pressure of 0.1-1 MPa, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 MPa and values ​​between any two groups, more preferably 0.1-0.5 MPa. The use of the catalyst provided by the present invention to catalyze the decomposition of a methanol aqueous solution containing hydrogen peroxide can make the reaction conditions more moderate and improve the industrial value.

[0032] In the present invention, there is no particular limitation on the distribution form of the catalyst. For example, the catalyst can be dispersed in the reactor in the form of particles and moved with the methanol aqueous solution containing hydrogen peroxide, or can be distributed in the reactor in the form of a bed for use. According to a preferred embodiment of the present invention, the decomposition reaction is carried out in a reactor. According to another preferred embodiment of the present invention, the decomposition reaction is carried out in a fixed bed reactor. Preferably, the decomposition reaction is carried out in a fixed bed reactor. The advantage of the decomposition reaction being able to be carried out in the above-mentioned reactor is that it is convenient for the filling and long-term operation of the catalyst in the industrial device.

[0033] In the present invention, when the catalyst is dispersed in the reactor in the form of particles and moves with the methanol aqueous solution containing hydrogen peroxide, the decomposition reaction is carried out in the reactor. Preferably, the amount of the catalyst is 0.1-5% of the mass of the methanol aqueous solution containing hydrogen peroxide, preferably 0.1-1%. Preferably, the residence time of the methanol aqueous solution containing hydrogen peroxide in the reactor is 0.01-24h, preferably 0.1-10h.

[0034] In the present invention, when the catalyst is distributed in the reactor in the form of a bed, the decomposition reaction is carried out in a fixed bed reactor. Preferably, the feed liquid mass space velocity of the methanol aqueous solution containing hydrogen peroxide is 0.01-20h -1 , more preferably 0.1-10h -1 .

[0035] In the present invention, preferably, the method further comprises mixing the product produced by the decomposition reaction with an optional inert gas and sending them together into a gas-liquid separator to remove the non-condensable gas therein. This operation mode is a conventional impurity removal method defined in the art, and the present invention does not specifically limit this, and those skilled in the art can adjust it according to actual needs.

[0036] According to a specific preferred embodiment of the present invention, the method comprises the following steps: in the presence of a catalyst, subjecting a methanol aqueous solution containing hydrogen peroxide to a decomposition reaction, wherein the conditions of the decomposition reaction include: a temperature of 30-100° C. and a pressure of 0.1-1 MPa; then mixing the product produced by the decomposition reaction with an optional inert gas and sending the mixture together to a gas-liquid separator to remove non-condensable gas therein;

[0037] The methanol aqueous solution containing hydrogen peroxide is an epoxidation reaction product obtained by epoxidation reaction of 3-chloropropylene and hydrogen peroxide. The epoxidation reaction is carried out in the presence of the catalyst of the present invention. Based on the total amount of the methanol aqueous solution containing hydrogen peroxide, the content of hydrogen peroxide in the methanol aqueous solution containing hydrogen peroxide is 0.02-1% by mass, and the content of methanol is 5-95% by mass. The epoxidation reaction further comprises separation, extraction, etc. to obtain the methanol aqueous solution containing hydrogen peroxide. The present invention does not particularly limit its specific operation mode and conditions.

[0038] The catalyst for decomposition reaction and epoxidation reaction comprises a titanium silicon molecular sieve with an MFI topological structure and aluminum oxide, wherein the titanium silicon molecular sieve with an MFI topological structure has a titanium-silicon molar ratio of 1:20-1:100; based on the total amount of the catalyst, the content of the titanium silicon molecular sieve with an MFI topological structure is 40-90% by mass, and the content of the aluminum oxide is 10-60% by mass; and the lateral crushing strength of the catalyst is 70-150 N / cm.

[0039] By adopting the method of the present invention, most of the residual hydrogen peroxide in the methanol aqueous solution can be decomposed before being discharged, thereby effectively eliminating the potential harm of wastewater with high hydrogen peroxide content to the environment, improving the environmental protection and safety of producing epichlorohydrin by epoxidation reaction of 3-chloropropene with hydrogen peroxide, and the catalyst avoids a large amount of component loss during long-term operation, and the decomposition activity remains stable. Compared with the prior art, the catalyst can better meet the industrial requirements for catalyst life.

[0040] The present invention will be described in detail below through examples.

[0041] In the present invention, in the examples and comparative examples, the titanium silicalite molecular sieve used is produced by Hunan Jianchang Petrochemical Co., Ltd. and has a brand name of HTS; starch and citric acid are both analytically pure reagents, and water is deionized water.

[0042] In order to illustrate the technical solution of the present invention, a simulation test is used for illustration. In the embodiments and comparative examples, hydrogen peroxide is an analytically pure reagent with a mass content of 30%; methanol is an analytically pure reagent with a mass content of greater than 99.5%.

[0043] In the present invention, in the examples, the lateral crushing strength of the catalyst is measured by a ZQJ-II intelligent particle strength tester produced by Dalian Intelligent Testing Machine Factory, with reference to the HG / T2782-1996 standard, and the measured lateral crushing strength is the average value of 20 particles.

[0044] In the present invention, the content of hydrogen peroxide in the reactor feed and discharge is determined by indirect iodine titration.

[0045] Preparation Examples 1-3 and Comparative Preparation Example 1 The preparation example is used to illustrate the preparation of the catalyst.

[0046] Preparation Example 1

[0047] 175.00 g HTS raw powder (titanium-silicon molar ratio of 1:30), 152.13 g aluminum hydroxide powder (produced by Shandong Zibo Taiguang Chemical Co., Ltd., with an aluminum oxide content of 71.9% and a BET specific surface area of ​​358 m 2 / g), 70.00g of starch and 12.10g of sesbania powder (produced by Henan Lankao Plant Gum Factory) were stirred and mixed in a kneader for 20min; then 292.88g of aluminum sol with an aluminum oxide content of 22.4% (produced by Hunan Jianchang Petrochemical Co., Ltd.), 14.15g of octylphenol polyoxyethylene (15) ether (OP-15, produced by Hebei Xingtai Kewang Chemical Additive Co., Ltd.) and 15.00g of deionized water were added in sequence and kneaded into a mass. The total mass of starch, sesbania powder and OP-15 in the kneaded material was 55.0% of the mass of the HTS original powder. Kneading was continued for 70min to obtain an extrudable plastic molding; a twin-screw extruder was used to pass through The catalyst was squeezed into wet, elongated solid cylindrical strips through a perforated plate. After being left to air at room temperature for 24 hours, the strips were put into a box-type resistance furnace and heated from room temperature to 120°C at a heating rate of 5°C / min and kept for 5 hours. The strips were then heated to 550°C at a heating rate of 3°C / min and kept for 15 hours. After natural cooling, cylindrical strip catalyst A1 was obtained. The mass content of titanium silicon molecular sieve in the shaped catalyst was 50%, the content of alumina was 50%, the mass ratio of alumina from aluminum hydroxide powder to that from aluminum sol was 1.67, and the side crushing strength was 95.4N / cm.

[0048] Preparation Example 2

[0049] 210.00 g HTS raw powder (titanium-silicon molar ratio of 1:50), 112.90 g aluminum hydroxide powder (produced by Shandong Zibo Taiguang Chemical Co., Ltd., with an aluminum oxide content of 71.9% and a BET specific surface area of ​​358 m 2 / g), 113.75g of starch and 8.75g of sesbania powder (produced by Henan Lankao Plant Gum Factory) were stirred and mixed in a kneader for 30min; then 261.18g of aluminum sol with an aluminum oxide content of 22.5% (produced by Hunan Jianchang Petrochemical Co., Ltd.), 17.50g of octylphenol polyoxyethylene (15) ether (OP-15, produced by Hebei Xingtai Kewang Chemical Additive Co., Ltd.) and 21.00g of deionized water were added in sequence and kneaded into a mass. The total mass of starch, sesbania powder and OP-15 in the kneaded material was 66.7% of the mass of the HTS original powder. Kneading was continued for 90min to obtain an extrudable plastic molding; a twin-screw extruder was used to pass through The catalyst was squeezed into wet, elongated solid cylindrical strips through a perforated plate. After being left to air at room temperature for 36 hours, the strips were put into a box-type resistance furnace and heated from room temperature to 120°C at a heating rate of 3°C / min and kept for 3 hours. The strips were then heated to 560°C at a heating rate of 5°C / min and kept for 20 hours. After natural cooling, cylindrical strip catalyst A2 was obtained. The mass content of titanium silicon molecular sieve in the shaped catalyst was 60%, the content of aluminum oxide was 40%, the mass ratio of aluminum hydroxide powder to aluminum oxide in aluminum sol was 1.38, and the side crushing strength was 98.8N / cm.

[0050] Preparation Example 3

[0051] 262.50 g HTS raw powder (titanium-silicon molar ratio of 1:70), 68.35 g aluminum hydroxide powder (produced by Shandong Zibo Taiguang Chemical Co., Ltd., with an aluminum oxide content of 74.2% and a BET specific surface area of ​​445 m 2 / g), 78.75g of starch and 8.75g of sesbania powder (produced by Henan Lankao Plant Gum Factory) were stirred and mixed in a kneader for 60min; then 164.39g of aluminum sol with an aluminum oxide content of 22.4% (produced by Hunan Jianchang Petrochemical Co., Ltd.), 17.50g of octylphenol polyoxyethylene (15) ether (OP-15, produced by Hebei Xingtai Kewang Chemical Additive Co., Ltd.) and 21.00g of deionized water were added in sequence and kneaded into a mass. The total mass of starch, sesbania powder and OP-15 in the kneaded material was 40.0% of the mass of the HTS original powder. Kneading was continued for 120min to obtain an extrudable plastic molding; a twin-screw extruder was used to pass through The catalyst was squeezed into wet, elongated solid cylindrical strips through a perforated plate. After being left to air at room temperature for 24 hours, the strips were placed in a box-type resistance furnace and heated from room temperature to 120°C at a heating rate of 3°C / min and kept for 2 hours. The strips were then heated to 270°C at a heating rate of 5°C / min and kept for 1 hour. Subsequently, the strips were heated to 560°C at a heating rate of 4°C / min and kept for 24 hours. After natural cooling, cylindrical strip catalyst A3 was obtained. The mass content of titanium silicon molecular sieve in the molded catalyst was 75%, the content of aluminum oxide was 25%, the mass ratio of aluminum hydroxide powder to aluminum oxide in aluminum sol was 1.38, and the side crushing strength was 81.2 N / cm.

[0052] Comparative Preparation Example 1

[0053] The hydrogen peroxide decomposition catalyst B1 was prepared according to the method provided in CN114471591.

[0054] 139.73 g of aluminum hydroxide powder (aluminum oxide content 71.56% by mass, produced by Shandong Zibo Taiguang Chemical Co., Ltd.), 241.97 g of titanium dioxide (chemically pure reagent), 90.00 g of starch (analytical pure reagent), 10.00 g of sesbania powder (produced by Henan Lankao Plant Gum Factory), 264.26 g of aluminum sol with an aluminum oxide content of 22.69% by mass (produced by Hunan Jianchang Petrochemical Co., Ltd.), 20.00 g of octylphenol polyoxyethylene (15) ether (OP-15, produced by Hebei Xingtai Kewang Chemical Additive Co., Ltd.) and 3.00 g of dilute nitric acid with a nitric acid content of 2% by mass were fully kneaded in a multifunctional catalyst molding machine (produced by the Science and Technology Industry General Factory of South China University of Technology) to obtain a wet plastic body, and then extruded into strips. The solid cylindrical bars were dried at 8-16°C for 66 hours, and then placed in a drying oven at 55°C for 8 hours, and then placed in a box-type resistance furnace, heated from 8°C to 120°C at a heating rate of 9°C / min and kept for 3 hours, and then heated to 600°C at a heating rate of 10°C / min and kept for 30 hours. After natural cooling, a cylindrical composite metal oxide containing 60.01% by mass of titanium dioxide and 39.99% by mass of aluminum oxide was obtained.

[0055] The mass ratio of aluminum hydroxide powder, titanium dioxide, acidic aluminum sol, starch and sesbania powder, OP-15 and 2 mass % nitric acid is 100:173.2:189.1:71.6:14.3:2.1.

[0056] 150.00 g of a cylindrical strip of composite metal oxide containing 60.01% by mass of titanium dioxide and 39.99% by mass of aluminum oxide was impregnated in 250.00 g of an aqueous solution containing 12.42 g of ammonium molybdate tetrahydrate and 17.00 g of copper nitrate trihydrate in a sealed container at 35°C for 24 hours, and then the impregnated material was dried at 85°C and 105°C for 12 hours respectively, and then the dried material was calcined at 550°C for 20 hours. After natural cooling, a cylindrical strip of hydrogen peroxide decomposition catalyst B1 containing 54.32% by mass of titanium dioxide, 6.11% by mass of molybdenum trioxide, 3.38% by mass of copper oxide and 36.19% by mass of aluminum oxide was obtained, and the catalyst had a lateral crushing strength of 115.1 N / cm.

[0057] Example 1

[0058] The hydrogen peroxide decomposition catalyst A1 prepared in Preparation Example 1 was used to decompose hydrogen peroxide in a methanol aqueous solution in a stirred tank reactor, and the catalyst was shaped into short strips of 3-5 mm in length. The methanol aqueous solution contained 48.001% by mass of methanol, 0.504% by mass of hydrogen peroxide and the remainder of water, and the conditions for the decomposition reaction were: stirring speed 600r / min, decomposition temperature 60°C, decomposition pressure 0.4MPa, catalyst dosage 5% of the mass of the methanol aqueous solution, and decomposition time 30min. Liquid samples of feed and discharge were taken respectively, and according to the method disclosed in CN106140186A: in ammonium molybdate and acidic medium, hydrogen peroxide and potassium iodide were used to react to produce iodine, and then the iodine was produced by titration with a standard solution of sodium thiosulfate, thereby determining the mass fraction of hydrogen peroxide.

[0059] It was determined that the mass fraction of hydrogen peroxide before decomposition was 0.504%, the mass fraction of hydrogen peroxide after decomposition was 0.005%, and the decomposition rate of hydrogen peroxide was 99.0%.

[0060] Example 2

[0061] The hydrogen peroxide decomposition catalyst A1 prepared in Preparation Example 1 was used to decompose hydrogen peroxide in a methanol aqueous solution in a fixed bed reactor, and the catalyst was shaped into short strips of 3-5 mm in length. The methanol aqueous solution contained 47.281% by mass of methanol and 0.508% by mass of hydrogen peroxide and the remainder of water. The conditions for the decomposition reaction were: the feed mass hourly space velocity of the methanol aqueous solution was 1 h -1 , the decomposition temperature is 60°C, the decomposition pressure is 0.1 MPa, and the feeding time is 24 hours. Liquid samples of the feed and the discharge are taken respectively, and the mass fraction of hydrogen peroxide is determined according to the method of Example 1.

[0062] It was determined that after a continuous feeding time of 24 hours, the mass fraction of hydrogen peroxide before decomposition was 0.508%, the mass fraction of hydrogen peroxide after decomposition was 0.008%, and the decomposition rate of hydrogen peroxide was 98.4%.

[0063] Example 3

[0064] The hydrogen peroxide decomposition catalyst A1 prepared in Preparation Example 1 was used to decompose hydrogen peroxide in a methanol aqueous solution in a fixed bed reactor, and the catalyst was shaped into short strips of 3-5 mm in length. The methanol aqueous solution contained 46.244% by mass of methanol, 0.645% by mass of 3-chloropropylene glycol monomethyl ether, 0.167% by mass of 3-chloro-1,2-propylene glycol, 0.512% by mass of hydrogen peroxide, and the remainder of water. The conditions for the decomposition reaction were: the feed mass hourly space velocity of the methanol aqueous solution was 3h -1, the decomposition temperature is 75°C, the decomposition pressure is 0.1 MPa, and the feeding time is 24 hours. Liquid samples of the feed and the discharge are taken respectively, and the mass fraction of hydrogen peroxide is determined according to the method of Example 1.

[0065] It was determined that after a continuous feeding time of 24 hours, the mass fraction of hydrogen peroxide before decomposition was 0.512%, the mass fraction of hydrogen peroxide after decomposition was 0.003%, and the decomposition rate of hydrogen peroxide was 99.4%.

[0066] Example 4

[0067] The method of Example 3 was used to catalytically decompose hydrogen peroxide in methanol aqueous solution, except that the catalyst used was catalyst A2 prepared in Preparation Example 2, and the feed mass hourly space velocity of methanol aqueous solution was 6h -1 , the decomposition temperature is 80℃ and the decomposition pressure is 0.3MPa.

[0068] It was determined that after a continuous feeding time of 24 hours, the mass fraction of hydrogen peroxide before decomposition was 0.512%, the mass fraction of hydrogen peroxide after decomposition was 0.004%, and the decomposition rate of hydrogen peroxide was 99.2%.

[0069] Example 5

[0070] The method of Example 3 was used to catalytically decompose hydrogen peroxide in methanol aqueous solution, except that the catalyst used was catalyst A3 prepared in Preparation Example 3, and the feed mass hourly space velocity of methanol aqueous solution was 10h -1 , the decomposition temperature is 100℃ and the decomposition pressure is 0.5MPa.

[0071] It was determined that after a continuous feeding time of 24 hours, the mass fraction of hydrogen peroxide before decomposition was 0.512%, the mass fraction of hydrogen peroxide after decomposition was 0.002%, and the decomposition rate of hydrogen peroxide was 99.6%.

[0072] Example 6

[0073] The method of Example 3 was adopted to carry out catalytic decomposition of hydrogen peroxide in methanol aqueous solution, except that the continuous feeding time was 200 hours.

[0074] It was determined that after a continuous feeding time of 200 hours, the mass fraction of hydrogen peroxide before decomposition was 0.512%, the mass fraction of hydrogen peroxide after decomposition was 0.005%, and the decomposition rate of hydrogen peroxide was 99.0%.

[0075] X-ray fluorescence spectrometer (XRF) was used to analyze the mass content of the catalyst components before and after the test. It was determined that before the test, the titanium content of the catalyst (in terms of TiO2) was 5.45%, the silicon content (in terms of SiO2) was 44.55%, and the aluminum content (in terms of Al2O3) was 50.00%; after 200 hours of continuous feeding time, the titanium content of the catalyst (in terms of TiO2) was 5.37%, the silicon content (in terms of SiO2) was 44.48%, and the aluminum content (in terms of Al2O3) was 50.15%.

[0076] Example 7

[0077] The method of Example 3 was used to carry out catalytic decomposition of hydrogen peroxide in a methanol aqueous solution, except that the methanol aqueous solution contained 20 mass % of methanol and 0.204 mass % of hydrogen peroxide and the balance of water.

[0078] It was determined that after a continuous feeding time of 24 hours, the mass fraction of hydrogen peroxide before decomposition was 0.204%, the mass fraction of hydrogen peroxide after decomposition was 0.001%, and the decomposition rate of hydrogen peroxide was 99.5%.

[0079] Comparative Example 1

[0080] The method of Example 3 was used to carry out catalytic decomposition of hydrogen peroxide in methanol aqueous solution, except that the catalyst used was Catalyst B1 prepared in Comparative Preparation Example 1.

[0081] It was determined that after a continuous feeding time of 24 hours, the mass fraction of hydrogen peroxide before decomposition was 0.512%, the mass fraction of hydrogen peroxide after decomposition was 0.003%, and the decomposition rate of hydrogen peroxide was 99.4%.

[0082] Comparative Example 2

[0083] The method of Example 6 was used to catalytically decompose hydrogen peroxide in a methanol aqueous solution, except that the catalyst used was Catalyst B1 prepared in Comparative Preparation Example 1.

[0084] It was determined that after a continuous feeding time of 200 hours, the mass fraction of hydrogen peroxide before decomposition was 0.512%, the mass fraction of hydrogen peroxide after decomposition was 0.174%, and the decomposition rate of hydrogen peroxide was 66.0%.

[0085] X-ray fluorescence spectrometer (XRF) was used to analyze the mass content of catalyst components before and after the test. It was determined that before the test, the titanium content (in terms of TiO2) of the catalyst was 54.32%, the molybdenum content (in terms of MoO3) was 6.11%, the copper content (in terms of CuO) was 3.38%, and the aluminum content (in terms of Al2O3) was 36.19%; after 200 hours of continuous feeding time, the titanium content (in terms of TiO2) of the catalyst was 56.72%, the molybdenum content (in terms of MoO3) was 2.14%, the copper content (in terms of CuO) was 1.09%, and the aluminum content (in terms of Al2O3) was 40.05%.

[0086] It can be seen from the preparation examples 1-3 in combination with the examples 1-7 and the comparative examples 1-2 that the method of the present invention, using the catalyst of the specific composition and strength of the present invention, can reduce the mass fraction of hydrogen peroxide in the methanol aqueous solution from 0.5% to below 0.01%, preferably to below 0.005%, after a continuous feeding time of 24-200 hours, and the content of the catalyst component is stable without significant loss. While the comparative example method can reduce the mass fraction of hydrogen peroxide in the methanol aqueous solution to below 0.01% within a relatively short continuous feeding time, as the continuous feeding time increases, active components such as molybdenum and copper are significantly lost, resulting in a significant decrease in the decomposition rate of hydrogen peroxide. After 200 hours, the mass fraction of hydrogen peroxide in the methanol aqueous solution reaches 0.174%, which is difficult to meet the industrial strength requirements for the loaded catalyst.

[0087] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for catalytically decomposing hydrogen peroxide in methanol aqueous solution, characterized in that: The method comprises the following steps: In the presence of a catalyst, a methanol aqueous solution containing hydrogen peroxide is subjected to a decomposition reaction, wherein the conditions of the decomposition reaction include: a temperature of 30-100° C.; The catalyst comprises titanium silicon molecular sieve with MFI topology structure and alumina; based on the total amount of the catalyst, the content of the titanium silicon molecular sieve with MFI topology structure is 40-90% by mass, and the content of the alumina is 10-60% by mass; the lateral crushing strength of the catalyst is 70-150N / cm.

2. The method according to claim 1, wherein: Based on the total amount of the catalyst, the content of the titanium silicon molecular sieve having an MFI topological structure is 50-85% by mass, and the content of the aluminum oxide is 15-50% by mass; Preferably, the catalyst has a side crushing strength of 75-120 N / cm.

3. The method according to claim 1 or 2, wherein: The aluminum oxide is provided by aluminum hydroxide powder and / or aluminum sol; Preferably, the titanium-silicon molar ratio of the titanium-silicon molecular sieve having the MFI topological structure is 1:20-1:

100.

4. The method according to any one of claims 1 to 3, wherein: The content of hydrogen peroxide in the methanol aqueous solution containing hydrogen peroxide is 0.02-1% by mass, preferably 0.05-0.6% by mass, based on the total amount of the methanol aqueous solution containing hydrogen peroxide; Preferably, based on the total amount of the methanol aqueous solution containing hydrogen peroxide, the content of methanol in the methanol aqueous solution containing hydrogen peroxide is 5-95% by mass, more preferably 20-80% by mass.

5. The method according to any one of claims 1 to 4, wherein: The methanol aqueous solution containing hydrogen peroxide is provided by at least one of the following: epoxidation reaction of 3-chloropropylene and hydrogen peroxide, epoxidation reaction of propylene and hydrogen peroxide, and production of hydrogen peroxide by anthraquinone method, preferably by epoxidation reaction of 3-chloropropylene and hydrogen peroxide.

6. The method according to any one of claims 1 to 5, wherein: The conditions of the decomposition reaction include: a temperature of 40-90°C, preferably 50-80°C; Preferably, the conditions for the decomposition reaction include: a pressure of 0.1-1 MPa, more preferably 0.1-0.5 MPa.

7. The method according to any one of claims 1 to 6, wherein: The decomposition reaction is carried out in a reactor; Alternatively, the decomposition reaction is carried out in a fixed bed reactor.

8. The method according to claim 7, wherein: The amount of the catalyst used is 0.1-5% of the mass of the methanol aqueous solution containing hydrogen peroxide, preferably 0.1-1%.

9. The method according to claim 7, wherein: The residence time of the methanol aqueous solution containing hydrogen peroxide in the reactor is 0.01-24h, preferably 0.1-10h.

10. The method according to claim 7, wherein: The mass space velocity of the feed liquid of the methanol aqueous solution containing hydrogen peroxide is 0.01-20h -1 , more preferably 0.1-10h -1 .