Carbon-coated non-noble metal supported modified hydrodehalogenation catalyst

Abstract

The application provides a preparation method of a hydrodehalogenation catalyst, which comprises the following steps: (1) dispersing a metal salt and a catalyst carrier in water, adding a carbonate and an alkali liquor to adjust the pH value of the mixed system, performing a first heating reaction, then washing and performing a first drying; (2) impregnating the solid obtained in the step (1) into a heteropoly acid solution, performing a second drying after solid-liquid separation, then performing a water vapor treatment; (3) adding a processing aid into the solid obtained in the step (2) and mixing to shape the mixture, then performing a third drying; (4) roasting the solid obtained in the step (3); and (5) obtaining the catalyst after high-temperature roasting of the solid obtained in the step (4) in a carbon-containing atmosphere. The application also provides a hydrodehalogenation method of halogenated organic substances, wherein the hydrodehalogenation catalyst prepared by the method is used for reaction.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalysts, in particular to a preparation method of a hydrodehalogenation catalyst, and application of the catalyst in a hydrodehalogenation reaction of halogenated organic compounds. BACKGROUND

[0002] Halogenated organic compounds are important chemical raw materials. However, due to their own non-degradability and harmfulness, halogenated organic compounds have great harm to the environment, and most of the treatment methods of these halogenated organic compounds in industry are treated as waste. If one or more halogen atoms on the halogenated organic compound can be removed by a suitable means, the halogenated compound without industrial use will become a useful low-halogen compound, which is helpful for waste treatment, saves enterprise cost, and achieves the concept of green production.

[0003] The main ways of catalytic hydrogenation dechlorination of halogenated organic compounds are caustic neutralization kettle hydrogenation process and alkali-free fixed bed hydrogenation process. The traditional caustic neutralization kettle hydrogenation process needs to add alkali liquor to neutralize the generated HCl in the reaction to avoid catalyst poisoning. This process needs to consume a large amount of alkali, has high cost, and generates a large amount of halogen-containing wastewater. The alkali-free fixed bed hydrogenation process can be continuously operated, greatly improves the production efficiency and yield. At the same time, the process does not need to add extra alkali, has low cost, and generates less wastewater, which is green and environmentally friendly. However, the main challenge of this process is that the catalyst is easy to be deactivated and has short service life.

[0004] The active centers of common hydrogenation dechlorination catalysts are mainly Pd, Pt, Rh and other noble metals, and Ni, Cu and other non-noble metals. Compared with noble metal catalysts, non-noble metal-based catalysts have lower cost, but there are two major challenges for non-noble metal catalysts: 1. Insufficient selectivity. The active centers of non-noble metal catalysts mainly depend on metal elements or simple oxides, and the electronic structure and geometric configuration are difficult to accurately control. For example, in the hydrogenation dechlorination of chlorobenzene, the nickel-based catalyst is easy to cause over-hydrogenation of benzene ring to generate cyclohexane due to too high surface electron density; 2. Contradiction between activity and stability. The interaction between traditional supports (such as Al2O3 and SiO2) and non-noble metals is weak, the dispersion degree of active components is low and easy to migrate and agglomerate, and the active phase is easy to flow out under HCl conditions. Improving the selectivity and stability of non-noble metal-based catalysts is one of the research focuses in this field.

[0005] At present, the core patents of non-noble metal hydrogenation dechlorination catalysts are mainly concentrated in kettle hydrogenation dechlorination, and there is still a blank in the systematic technical solutions for the selectivity regulation mechanism and long-term stability improvement of fixed bed hydrogenation dechlorination. Therefore, there is an urgent need in the field to develop a non-noble metal-based catalyst with stability and high selectivity, which can be applied to different hydrogenation dehalogenation reactions. SUMMARY

[0006] The first aspect of the present application provides a method for preparing a hydrodehalogenation catalyst, the method comprising the following steps:

[0007] (1) dispersing a metal salt and a catalyst carrier in water, adding a carbonate and an alkali solution to adjust the pH value of the mixed system, performing a first heating reaction, then washing and performing a first drying;

[0008] (2) impregnating the solid obtained in step (1) in a heteropoly acid solution, performing a second drying after solid-liquid separation, then performing a water vapor treatment;

[0009] (3) adding a processing aid to the solid obtained in step (2) and mixing to shape the mixture, then performing a third drying;

[0010] (4) calcining the solid obtained in step (3);

[0011] (5) obtaining the catalyst after high-temperature calcination of the solid obtained in step (4) in a carbon-containing atmosphere.

[0012] In an embodiment of the present application, the method further comprises: (4') mixing the solid obtained in step (4) with a carbon source solution to perform a hydrothermal reaction, performing a fourth drying after solid-liquid separation and washing; and then performing step (5).

[0013] In an embodiment of the present application, the metal ions in the metal salt in step (1) include one or more of Fe, Co, Ni, Cu, and Mn, and the acid radical ions include one or more of nitrate, acetate, sulfate, phosphate, and hydrochloride.

[0014] In an embodiment of the present application, the catalyst carrier includes one or more of silicon dioxide, aluminum oxide, zirconium oxide, and titanium dioxide.

[0015] In an embodiment of the present application, the carbonate includes sodium carbonate and / or potassium carbonate.

[0016] In an embodiment of the present application, the alkali solution includes NaOH and / or KOH.

[0017] In an embodiment of the present application, the mass ratio of the metal salt: catalyst carrier: carbonate: water is 0.001-0.1: 1: 0.001-0.1: 1-100, wherein the mass of the metal salt is calculated based on the metal amount.

[0018] In an embodiment of the present application, the heteropoly acid in step (2) has the chemical formula H m PM 12 O 40wherein M is one or more metals selected from Mo, W, V, Nb and Ta, and m = 3, 4 or 5.

[0019] In one embodiment of the present application, the mass ratio of the heteropoly acid: solid obtained in step (2): water is 0.02-0.2: 1: 5-50.

[0020] In one embodiment of the present application, the water vapor treatment is performed using a mixed gas of water vapor and a carrier gas, wherein the carrier gas comprises one or more of nitrogen, helium, and argon, and the water vapor in the mixed gas is 5% by volume to 30% by volume.

[0021] In one embodiment of the present application, in step (3), the processing aid comprises a binder and a lubricant.

[0022] In one embodiment of the present application, the mass ratio of the solid obtained in step (2): binder: lubricant is 1: 0.01-0.1: 0.01-0.05.

[0023] In one embodiment of the present application, in step (4'), the carbon source comprises one or more of glucose, chitosan, glycogen, cellulose, oligosaccharide, starch, and lignin.

[0024] In one embodiment of the present application, the mass ratio of the carbon source: solid obtained in step (4): water is 0.01-0.1: 1: 10-30.

[0025] In one embodiment of the present application, the hydrothermal temperature is 150-250°C, and the time is 6-36h.

[0026] In one embodiment of the present application, the first drying temperature is 40-120°C, and the first drying time is 6-72h.

[0027] In one embodiment of the present application, the second drying temperature is 50-140°C, and the second drying time is 4-56h.

[0028] In one embodiment of the present application, the third drying is a multi-stage drying, wherein the first stage temperature is 30-60°C, and the time is 8-36h, and the second stage temperature is 90-150°C, and the time is 4-72h.

[0029] In one embodiment of the present application, the fourth drying temperature is 40-150°C, and the fourth drying time is 6-64h.

[0030] In one embodiment of the present application, the air calcination temperature is 400-600°C, and the calcination time is 6-36h.

[0031] In one embodiment of the present application, the calcination temperature in the carbon-containing gas atmosphere is 600-800°C, and the calcination time is 6-24h.

[0032] A second aspect of the present application provides a hydrodehalogenation catalyst prepared by the preparation method of the present application.

[0033] A third aspect of the present application provides a method for hydrodehalogenation of halogenated organic compounds, which uses the hydrodehalogenation catalyst described herein.

[0034] A fourth aspect of the present application provides a hydrodehalogenation product prepared by the method for hydrodehalogenation described herein. DETAILED DESCRIPTION

[0035] The present inventors found that by loading the first metal with a support / precursor sol as a precursor, and by redistributing the first metal, P and the polyatomic metal in the heteropoly acid through high-temperature steam treatment of the heteropoly acid, the selectivity of the first metal for hydrodechlorination and its stability under HCl conditions were improved by adjusting the coordination environment of the first metal; and then by growing a surface carbon coating layer, the thermal stability of the catalyst under hydrodechlorination conditions was further improved, and on this basis, the present application was completed.

[0036] The ranges disclosed herein are defined by the lower and upper limits in the form of a range, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The ranges defined in this way can include or exclude the end values, and can be arbitrarily combined, i.e. any lower limit can be combined with any upper limit to form a range. For example, if the ranges 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges 60-110 and 80-120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4 and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise stated, the numerical range "a-b" represents a shorthand notation for any integer combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is just a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer ≥2, it is equivalent to disclose that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0037] In this application, all the embodiments and preferred embodiments mentioned herein can be combined with each other to form new technical solutions, unless otherwise stated.

[0038] In the present application, all the technical features and preferred features mentioned in the present application can be combined to form new technical solutions, if no special instructions are given.

[0039] In the present application, all the steps mentioned in the present application can be performed in sequence or randomly, but preferably in sequence, if no special instructions are given. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method mentioned can further comprise step (c), which means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0040] In the present application, the terms “comprise” and “include” mean open-ended, and can also mean closed-ended, if no special instructions are given. For example, the terms “comprise” and “include” can mean that other components not listed can also be included, or only the listed components can be included.

[0041] In the description herein, it is to be noted that, unless otherwise specified, “above”, “below” include the number itself, and “one or more” means two or more.

[0042] In the description herein, unless otherwise specified, the term “or” is inclusive. For example, the phrase “A or B” means “A, B, or both A and B”. More specifically, any of the following conditions satisfy the condition “A or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0043] In the present application, unless otherwise specified, the percentage (%) or the part refers to the percentage by weight or the parts by weight of the composition.

[0044] In the present application, unless otherwise specified, the sum of the contents of the components in the composition is 100%.

[0045] In the present application, unless otherwise specified, the sum of the parts of the components in the composition can be 100 parts by weight.

[0046] In the present application, unless otherwise specified, “a combination thereof” means a multi-component mixture of the elements, for example, a two-component, a three-component, a four-component, and up to the maximum possible multi-component mixture.

[0047] Unless otherwise specified, the term “one” used in the present specification means “at least one”.

[0048] In this text, unless otherwise stated, each reaction is carried out at room temperature and normal pressure.

[0049] The first aspect of the present application provides a method for preparing a hydrodehalogenation catalyst, the method comprising the following steps:

[0050] (1) dispersing a metal salt and a catalyst carrier in water, adding a carbonate and an alkali solution to adjust the pH value of the mixed system, carrying out a first heating reaction, then washing and carrying out a first drying;

[0051] (2) impregnating the solid obtained in step (1) in a heteropoly acid solution, carrying out a second drying after solid-liquid separation, then carrying out a water vapor treatment;

[0052] (3) adding a processing aid to the solid obtained in step (2) and mixing to shape the mixture, then carrying out a third drying;

[0053] (4) calcining the solid obtained in step (3);

[0054] (5) obtaining the catalyst after high-temperature calcination of the solid obtained in step (4) in a carbon-containing atmosphere.

[0055] The hydrodehalogenation catalyst is a supported catalyst prepared by loading an active metal component on a catalyst carrier in a certain way. The supported hydrodehalogenation catalyst can be used in the hydrodechlorination reaction of halogenated aromatic compounds, such as chlorinated aromatic compounds, including but not limited to one or more of chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,3,5-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, and one or more of chloronaphthalene and chlorofluorene.

[0056] In a specific embodiment of the present application, the metal ions in the metal salt in step (1) include but are not limited to one or more of Fe, Co, Ni, Cu, and Mn, and the acid radical ions include but are not limited to one or more of nitrate, acetate, sulfate, phosphate, and hydrochloride.

[0057] In a specific embodiment of the present application, the catalyst carrier includes but is not limited to one or more of silicon dioxide, aluminum oxide, zirconium oxide, and titanium dioxide. Preferably, the catalyst carrier is preferably a sol-forming aluminum oxide, such as pseudoboehmite. The technical indicators of the pseudoboehmite are a specific surface area ≥ 250 m 2 / g, a sol index ≥ 92%, and a pore volume ≥ 0.6 mL / g.

[0058] In one specific embodiment of the present application, the carbonate salt includes, but is not limited to, sodium carbonate, potassium carbonate; the alkali solution includes, but is not limited to, NaOH, KOH, and the pH value of the mixed system is adjusted to be alkaline, such as adjusting the pH value to be 9.0-10.0.

[0059] In one specific embodiment of the present application, the mass ratio of the metal salt: catalyst carrier: carbonate salt: water is 0.001-0.1:1:0.001-0.1:1-100, preferably 0.005-0.075:1:0.003-0.05:2-50, more preferably 0.01-0.07:1:0.005-0.04:4-40, wherein the mass of the metal salt is calculated based on the metal amount.

[0060] In one specific embodiment of the present application, in step (1), the first heating temperature can be 40-70℃, preferably 45-65℃, and the heating time can be 2-72h, preferably 4-65h.

[0061] In one specific embodiment of the present application, in step (1), the first washing liquid can be a potassium carbonate solution, a sodium carbonate solution, or a mixture of the two.

[0062] In one specific embodiment of the present application, in step (1), the first drying temperature can be 40-120℃, preferably 60-100h, and the time can be 6-72h, preferably 15-60h.

[0063] In the present application, the term "heteropoly acid" refers to a polyoxometalate compound containing a central atom and a coordination atom. The heteropoly acid has a chemical formula H m PM 12 O 40 wherein M is one or more metals selected from Mo, W, V, Nb and Ta, preferably W or Mo, and m=3, 4 or 5. In step (2), the solid obtained in step (1) is immersed into a heteropoly acid solution, and after solid-liquid separation, second drying is performed, followed by water vapor treatment.

[0064] In one specific embodiment of the present application, the mass ratio of the heteropoly acid: the solid obtained in step (2): water is 0.01-0.5:1:1-100, preferably 0.02-0.2:1:5-50.

[0065] In one specific embodiment of the present application, the reaction temperature of the solid obtained in step (1) with the heteropoly acid is 25-80℃, preferably 40-70℃, and the time is 2-24h, preferably 4-20h.

[0066] In one specific embodiment of the present application, the water vapor treatment is performed using a mixture of water vapor and carrier gas, the carrier gas comprising one or more of nitrogen, helium, argon, and the water vapor content in the mixture being 5% to 30% by volume. The water vapor treatment temperature is 400 to 600 o C, preferably 425 to 570 o C, for a time period of 6 to 24 h, preferably 8 to 20 h.

[0067] In one specific embodiment of the present application, the second drying temperature can be 50 to 140 °C, preferably 60 to 125 °C, and the time period can be 4 to 56 h, preferably 6 to 52 h.

[0068] In the present application, the high-temperature water vapor treatment of the phosphorus-based heteropoly acid facilitates the redistribution of the metal, P, and polyatomic metal in the heteropoly acid in the metal salt, facilitates the transfer of electrons to the active metal, changes the electron cloud density of the metal on the catalyst surface, reduces the adsorption strength of the metal to the chlorine atom, and improves the selectivity of the hydrogenation dechlorination while reducing the loss of the metal.

[0069] In the present application, the term "processing aid" refers to an agent that facilitates the shaping of the catalyst, including but not limited to a binder, a lubricant, etc. The binder and the lubricant are added to the solid obtained in step (2) and mixed to shape the mixture, the wet material is molded to obtain a molded product, and the third drying is performed after the molded product is obtained. The binder includes but is not limited to one or more of polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol, and animal glue; the lubricant includes but is not limited to one or more of stearic acid, sodium stearate, magnesium stearate, calcium stearate, paraffin, and sesbania gum. The shaping method includes but is not limited to tablet shaping, extrusion shaping, spray drying shaping, or rotation shaping. The shape of the molded product includes but is not limited to tablet-shaped, cylindrical, or ring-shaped for tablet shaping, preferably cylindrical or tablet-shaped, or columnar, honeycomb-shaped, or clover-shaped for extrusion shaping, preferably cylindrical or clover-shaped, or spherical for rotation shaping. For the purpose of shaping strength, the third drying can be performed in stages, first at a low temperature to slowly evaporate the water, and then at a high temperature to remove the remaining water.

[0070] In one specific embodiment of the present application, in step (3), the mass ratio of the solid obtained in step (2) to the binder to the lubricant is 1:0.01 to 0.1:0.01 to 0.05.

[0071] In one specific embodiment of the present application, the third drying is multi-stage drying, in which the first stage temperature is 30 to 60 °C, and the time period is 8 to 36 h, and the second stage temperature is 90 to 150 °C, and the time period is 4 to 72 h.

[0072] In step (4), the molded product is calcined in air. In the present application, the specific means and manner of calcination are not particularly limited as long as the object of the present application can be achieved. In the present application, the "calcination" can use the conventional calcination temperature in the art. In one specific embodiment of the present application, the air calcination temperature is 400-600°C, and the calcination time is preferably 6-36 h.

[0073] In one specific embodiment of the present application, the preparation method further comprises step (4'): mixing the solid obtained in step (4) with a carbon source solution to perform a hydrothermal reaction, followed by solid-liquid separation and washing, and then fourth drying. The organic carbon source is combined onto the surface of the catalyst by mixing with the carbon source solution and performing a hydrothermal reaction, and then a carbon protective film is formed on the surface of the catalyst by pyrolysis treatment in a carbon-containing atmosphere, thereby inhibiting the sintering and agglomeration of the metal under high-temperature reaction conditions. The carbon source solution includes, but is not limited to, one or more of glucose, chitosan, glycogen, cellulose, oligosaccharide, starch, and lignin.

[0074] In one specific embodiment of the present application, the mass ratio of the carbon source: the solid obtained in step (4): water is 0.01-0.1:1:10-30.

[0075] In one specific embodiment of the present application, the hydrothermal temperature is 150-250°C, and the time is 6-36 h.

[0076] In one specific embodiment of the present application, the fourth drying temperature is 40-150°C, and the time is 6-64 h.

[0077] After the solid obtained in step (4) or the solid obtained in step (4') is calcined at a high temperature in a carbon-containing atmosphere, the catalyst is obtained. The carbon-containing atmosphere includes, but is not limited to, CO and CH4. The calcination temperature in the carbon-containing atmosphere can be 600-800°C, and the calcination time is preferably 6-24 h.

[0078] In the present application, the specific means and manner of separation, washing, and drying of the catalyst are not particularly limited as long as the object of the present application can be achieved.

[0079] The drying step can be performed in an inert gas atmosphere or vacuum drying. In one specific embodiment of the present application, the drying is performed in an inert gas atmosphere, and the inert gas includes one or more of N2, He, Ne, and Ar. The specific temperature and time of drying are not particularly limited as long as the object of the present application can be achieved.

[0080] Yet another aspect of the present application provides a method for hydrodehalogenation of a halogenated organic compound, which uses the hydrodehalogenation catalyst described herein for the reaction.

[0081] In the present application, the "halogenated organic" refers to a compound in which a functional group in an organic compound is replaced by a halogen atom, such as fluorine, chlorine, bromine, iodine. The halogenated organic includes, but is not limited to, chlorinated alkanes, chlorinated aromatic hydrocarbons, brominated alkanes, etc. Preferably, the halogenated organic is a chlorine-containing organic, including but not limited to one or more of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,3-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,3,5-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, 1,2,3,4,5-pentachlorobenzene, hexachlorobenzene, and one or more of chlorinated naphthalene, chlorinated biphenyl, chlorinated fluorene, brominated alkanes.

[0082] In the present application, the hydrogenation dehalogenation method can be carried out by a tank hydrogenation process or a fixed bed hydrogenation process. The tank hydrogenation process includes hydrogenation dehalogenation reaction of halogenated organic and hydrogen in the presence of the hydrogenation dehalogenation catalyst and base. The fixed bed hydrogenation process includes hydrogenation dehalogenation reaction of halogenated organic and hydrogen in the presence of the hydrogenation dehalogenation catalyst.

[0083] The catalytic hydrogenation dechlorination reaction can be carried out by pure chlorine-containing organic or a mixture of chlorine-containing organic and solvent, including but not limited to one or more of benzene, toluene, xylene, mesitylene, DMF.

[0084] In one specific embodiment of the present application, the hydrogenation dehalogenation reaction is a catalytic hydrogenation dechlorination reaction, the reaction temperature of the catalytic hydrogenation dechlorination reaction is 80-160℃, the molar ratio of chlorine-containing organic to H2 is 1:20-60, the catalyst mass space velocity is 0.1-2h -1 , and the pressure is 0.5-2MPa.

[0085] Taking chlorobenzene as an example, chlorobenzene is removed by catalytic hydrogenation dehalogenation to obtain benzene, and excessive hydrogenation will generate cyclohexane. The hydrogenation dehalogenation catalyst obtained by the present application can improve the selectivity of benzene and prevent excessive hydrogenation in the hydrogenation dehalogenation reaction.

[0086] The advantages of the present application are:

[0087] 1. The present application disperses and coordinates the protection of non-noble metals by high-temperature steam modification of heteropoly acid, improves the stability of the metal under HCl conditions, solves the problem of serious loss of non-noble metals, and effectively improves the stability of the catalyst in the hydrogenation dehalogenation reaction.

[0088] 2. The present application can effectively prevent the sintering and agglomeration of metal components under the condition of hydrogenation dechlorination by growing a further carbon coating layer on the surface of the catalyst.

[0089] 3. The catalyst can prevent excessive hydrogenation in the hydrogenation dehalogenation reaction to some extent while maintaining high activity.

[0090] Unless otherwise indicated, the various starting materials used in the application can be obtained commercially or prepared by conventional methods well known by those skilled in the art. Unless otherwise defined or specified, all of the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method and material similar or equivalent to those described can be used in the method of the present application. Other aspects of the present application will be apparent to those skilled in the art from the disclosure herein.

[0091] Examples

[0092] The present application will be further described in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods in the following examples, if not otherwise specified, are generally determined according to the national standards. If there is no corresponding national standard, it is determined according to the general international standards, conventional conditions, or according to the conditions suggested by the manufacturer. Unless otherwise specified, all parts are by weight, all percentages are by weight, and the polymer molecular weight is the number average molecular weight.

[0093] Raw material sources and preparation

[0094] Main reagents for experiment

[0095] Reagent Type Manufacturer Nickel nitrate 98.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Pseudo-boehmite Specific surface area: 452 m 2 / g, sol index: 95%, pore volume 0.92 mL / g Shanghai Maikelin Biochemical Technology Co., Ltd. Potassium carbonate 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Sodium carbonate 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. H3PW 12 O 40 ]]> 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Polyvinyl alcohol 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Stearic acid 98.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Ferric nitrate 98.5% National Pharmaceutical Group Chemical Reagent Co., Ltd. Cobalt nitrate 98.5% National Pharmaceutical Group Chemical Reagent Co., Ltd. Copper nitrate 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. H3PV 12 O 40 ]]> 99.0% Xi'an Qi Yue Biological Technology Co., Ltd. H3PNb 12 O 40 ]]> 99.5% National Pharmaceutical Group Chemical Reagent Co., Ltd. H3PMo 12 O 40 ]]> 98.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. H3PTa 12 O 40 ]]> 99.0% Xi'an Qi Yue Biological Technology Co., Ltd. Chitosan 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Glucose 99.6% National Pharmaceutical Group Chemical Reagent Co., Ltd. Glycogen 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Cellulose 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Lignin 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. Oligosaccharide 99.0% Dongguan East Sugar Group Co., Ltd. Starch 99.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. 1,4-dichlorobenzene, 1,3-dichlorobenzene Mixed ratio of 1:1, purity of 99.5%, 98.0% respectively National Pharmaceutical Group Chemical Reagent Co., Ltd. 1,2,3-trichlorobenzene, 1,3,5-trichlorobenzene Mixed ratio of 1:1, purity of 98.0%, 99.0% respectively National Pharmaceutical Group Chemical Reagent Co., Ltd. Tetrachlorobenzene, pentachlorobenzene mixture Mixed ratio of 1:1, purity of 96.0%, 98.0% respectively National Pharmaceutical Group Chemical Reagent Co., Ltd. 2-chloronaphthalene 98.0% National Pharmaceutical Group Chemical Reagent Co., Ltd. 2,7-dichlorofluorene 98.0% National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0096] Main instruments for experiment

[0097] Instrument name Model Manufacturer Electronic balance JA31002 Shanghai Yitian Scientific Instrument Co., Ltd. Fixed bed reactor HF-V1 Shanghai Baigar Technology Group Co., Ltd. Kettle type reactor BKLS-5L Shanghai Baigar Technology Group Co., Ltd. Gas chromatograph 7890A Agilent Technology Co., Ltd. Inductively coupled plasma mass spectrometry 7900 Agilent Technology Co., Ltd.

[0098] Gas chromatography test conditions

[0099]

[0100] Method for calculating conversion rate and selectivity: collect the liquid after reaction, analyze the components by Agilent 7890 gas chromatography, use hydrogen flame detector (FID), and calculate the concentration of each component by external standard method, wherein

[0101] Conversion rate (%) = 1 - (substrate concentration after reaction / substrate concentration before reaction) x 100%,

[0102] Selectivity (%) = 1 - (corresponding material concentration / total product concentration) x 100%.

[0103] Method for testing catalyst stability:

[0104] Catalyst life (h) refers to the length of time the catalyst is operated until the reaction conversion and reaction selectivity decay less than or equal to 80%.

[0105] In a fixed bed hydrogenation process, the catalyst life is evaluated as follows: Catalyst life (h) refers to the length of time the catalyst is operated until the reaction conversion and reaction selectivity decay less than or equal to 80%.

[0106] Catalyst active metal content test method:

[0107] The catalyst active metal content is tested by ICP-MS (inductively coupled plasma mass spectrometry).

[0108] Example 1

[0109] The catalyst is prepared according to the following method:

[0110] 24.78 g of nickel nitrate is dispersed in 900 g of water with 200 g of pseudoboehmite, while stirring, 6.0 g of potassium carbonate is slowly added, the pH value of the mixed system is adjusted to 9.6 with KOH, heated to 57°C and reacted for 20 h, then washed several times with a potassium carbonate washing solution and water, and dried at 100°C for 10 h.

[0111] 80.0 g of the dried solid is impregnated in 1600 g of water containing 12 g of H3PW 12 O 40 , reacted at 45°C for 15 h, solid-liquid separation, dried at 120°C for 24 h, then treated with water vapor, argon as carrier gas, water vapor volume ratio 15%, reacted at 535°C for 8 h.

[0112] 50.0 g of the solid after water vapor treatment, 2.5 g of polyvinyl alcohol, 1.5 g of stearic acid, and 10.6 g of water are mixed uniformly to obtain a wet material, the wet material is extruded into a cylindrical mold. After drying the mold at 50°C for 12 h and then at 110°C for 48 h, the dried mold is calcined in an air atmosphere at 480°C for 26 h.

[0113] 10.4 g of the calcined mold is mixed uniformly with 0.8 g of chitosan and 100 g of ultrapure water, and treated at 170°C for 26 h. After the reaction is completed, solid-liquid separation is performed and the wet solid is washed several times with ultrapure water, and then dried at 100°C for 36 h, and then calcined in a CO atmosphere at 700°C for 12 h to obtain the target catalyst, and the catalyst active metal content is tested.

[0114] The catalyst is applied to a fixed bed hydrogenation process:

[0115] The granular catalyst is loaded into a fixed bed reactor, and a chlorobenzene solution is provided, H2 is used as the reaction gas, and the reaction space velocity is controlled at 1.0 h -1The reaction temperature was 100°C, the hydrogen / chlorobenzene molar ratio was 20, the pressure was 0.5 MPa, and chlorobenzene and hydrogen were reacted over the catalyst bed to obtain dechlorination products. The reaction liquid was collected and analyzed by GC (gas chromatography).

[0116] Comparative Example 1

[0117] The 24.78 g of nickel nitrate and 200 g of pseudoboehmite were dispersed in 900 g of water, 6.0 g of potassium carbonate was slowly added while stirring, the pH value of the mixed system was adjusted to 9.6 using KOH, and the system was heated to 57°C for 20 h of reaction time. After washing several times with a potassium carbonate washing solution and water, the system was dried at 100°C for 10 h.

[0118] The 50.0 g of dried solid, 2.5 g of polyvinyl alcohol, 1.5 g of stearic acid, and 10.6 g of water were mixed to obtain a wet material. The wet material was extruded and molded to obtain a cylindrical molded product. The molded product was dried at 50°C for 12 h and then at 110°C for 48 h. The dried molded product was calcined in an air atmosphere at 480°C for 26 h. 10.4 g of the calcined molded product was calcined in a CO atmosphere at 700°C for 12 h to obtain the target catalyst.

[0119] Comparative Example 2

[0120] The 24.78 g of nickel nitrate and 200 g of pseudoboehmite were dispersed in 900 g of water, 6.0 g of potassium carbonate was slowly added while stirring, the pH value of the mixed system was adjusted to 9.6 using KOH, and the system was heated to 57°C for 20 h of reaction time. After washing several times with a potassium carbonate washing solution and water, the system was dried at 100°C for 10 h.

[0121] The 50.0 g of dried solid, 2.5 g of polyvinyl alcohol, 1.5 g of stearic acid, and 10.6 g of water were mixed to obtain a wet material. The wet material was extruded and molded to obtain a cylindrical molded product. The molded product was dried at 50°C for 12 h and then at 110°C for 48 h. The dried molded product was calcined in an air atmosphere at 480°C for 26 h.

[0122] 10.4 g of the calcined molded product was mixed with 0.8 g of chitosan and 100 g of ultrapure water, and the mixture was treated at 170°C for 26 h. After the reaction was completed, solid-liquid separation was performed and the wet solid was washed several times with ultrapure water. The washed wet solid was dried at 100°C for 36 h and then calcined in a CO atmosphere at 700°C for 12 h to obtain the target catalyst.

[0123] Example 2

[0124] Disperse 24.78 g of nickel nitrate and 200 g of pseudo-boehmite in 900 g of water, while stirring, slowly add 6.0 g of potassium carbonate, adjust the pH of the mixed system to 9.6 with KOH, heat to 57°C and react for 20 h, then wash several times with a potassium carbonate washing solution and water, and dry at 100°C for 10 h.

[0125] Take 80.0 g of the dried solid and immerse it in 1600 g of water containing 12 g of H3PW 12 O 40 at 45°C for 15 h, separate the solid and liquid, dry at 120°C for 24 h, then treat with steam, with argon as the carrier gas and a water vapor volume fraction of 15%, at 535°C for 8 h.

[0126] Mix 50.0 g of the steam-treated solid, 2.5 g of polyvinyl alcohol, 1.5 g of stearic acid, and 10.6 g of water to obtain a wet material, extrude the wet material to obtain a cylindrical molded product. Dry the molded product at 50°C for 12 h, then at 110°C for 48 h, and calcine the dried molded product in an air atmosphere at 480°C for 26 h. Take the calcined product and calcine it in a CO atmosphere at 700°C for 12 h to obtain the target catalyst.

[0127] Examples 3-11

[0128] On the basis of Example 1, change the type of metal, the type of carbonate, and the mass ratio thereof in Step 1, while ensuring that the remaining conditions remain unchanged.

[0129] Use the obtained catalyst in a fixed-bed hydrogenation process to evaluate the performance of the catalyst, and the results are as follows:

[0130] Table 1 Comparison of the results of the fixed-bed catalytic hydrogenation reaction using the catalysts prepared in different examples

[0131]

[0132] As can be seen from the data in Table 1, the active metal is preferably Ni-based and Ni-based composite metal, the Ni content is preferably 0.4-5%, and impregnation with a heteropoly acid and steam treatment can significantly improve the life of the catalyst and increase the selectivity of hydrodechlorination.

[0133] Examples 12-17

[0134] On the basis of Example 1, only change the type of heteropoly acid and the mass ratio thereof in Step 2, while ensuring that the remaining conditions remain unchanged, to perform Examples 12-17.

[0135] Use the obtained catalyst in a fixed-bed hydrogenation process to evaluate the performance of the catalyst, and the results are as follows:

[0136] Table 2 Comparison of results of catalysts prepared in different examples for fixed bed catalytic hydrogenation reaction

[0137]

[0138] As can be seen from Table 2, the heteropoly acids based on W, V, Nb, Mo and Ta can all improve the catalyst life and increase the selectivity of hydrodechlorination, and the heteroatom based on W or Mo is preferred.

[0139] Examples 18-23

[0140] On the basis of Example 1, only the type and mass ratio of carbon source in step 5 were changed, and the remaining conditions were kept unchanged, to carry out Examples 18-23.

[0141] The obtained catalysts were used in fixed bed hydrogenation process, and the catalyst performance was evaluated, and the results were as follows:

[0142] Table 3 Comparison of results of catalysts prepared in different examples for fixed bed catalytic hydrogenation reaction

[0143]

[0144] As can be seen from Table 3, using glucose, chitosan, glycogen, cellulose, lignin, oligosaccharide, starch and the like as the carbon source for coating treatment can improve the catalyst life, and the carbon source is preferably glucose, glycogen, cellulose, oligosaccharide and / or starch.

[0145] Examples 24-28

[0146] On the basis of Example 1, the composition of carrier gas and the proportion of water vapor in step 2, the reaction temperature and time were changed, and the remaining conditions were kept unchanged, to carry out Examples 24-28.

[0147] The obtained catalysts were used in fixed bed hydrogenation process, and the catalyst performance was evaluated, and the results were as follows:

[0148] Table 4 Comparison of results of catalysts prepared in different examples for fixed bed catalytic hydrogenation reaction

[0149]

[0150] Examples 29-33

[0151] On the basis of Example 1, the calcination conditions in steps 4 and 6 were changed, and the remaining conditions were kept unchanged, to carry out Examples 29-33.

[0152] The obtained catalysts were used in fixed bed hydrogenation process, and the catalyst performance was evaluated, and the results were as follows:

[0153] Table 5 Comparison of the results of the fixed-bed catalytic hydrogenation reaction using the catalysts prepared in different examples

[0154]

[0155] Examples 34-38

[0156] On the basis of Example 1, chlorobenzene was replaced by other chloroaromatic compounds, and the remaining conditions were unchanged, and Examples 34-38 were carried out. The obtained catalysts were used in the fixed-bed hydrogenation process, and the catalyst performance was evaluated by changing the fixed-bed catalytic hydrogenation process parameters according to the reactants, and the results were as follows:

[0157] Table 6 Comparison of the results of the fixed-bed catalytic hydrogenation reaction using the catalyst prepared in Example 1 with different substrates

[0158]

[0159] The above description is merely preferred embodiments of the present application, but not to confine the scope of the present application. The essential technical content of the present application is defined in the scope of the claims of the application. Any technical entity or method completed by others, if it is the same as or an equivalent change of the defined scope of the claims of the application, will be considered to be covered in the scope of the claims.

[0160] All the documents mentioned in the present application are cited as references in the present application, as if each document is cited as a reference individually. In addition, it should be understood that, after reading the above description of the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the claims attached to the present application.

Claims

1. A method for preparing a hydrodehalogenation catalyst, the method comprising the following steps: (1) dispersing a metal salt and a catalyst carrier in water, adding a carbonate and an alkali liquor to adjust the pH value of the mixed system, performing a first heating reaction, then washing and performing a first drying, wherein the metal ion in the metal salt comprises one or more of Fe, Co, Ni, Cu and Mn, the acid radical ion comprises one or more of nitrate, acetate, sulfate, phosphate and hydrochloride, and the catalyst carrier comprises one or more of silicon dioxide, aluminum oxide, zirconium oxide and titanium dioxide, wherein the mass ratio of the metal salt: catalyst carrier: carbonate: water is 0.001-0.1: 1: 0.001-0.1: 1-100, and the mass of the metal salt is calculated based on the metal amount; (2) impregnating the solid obtained in step (1) into a heteropoly acid solution, solid-liquid separation, followed by second drying, and then water vapor treatment, the heteropoly acid having the chemical formula H m PM 12 O 40 wherein M is one or more metals selected from Mo, W, V, Nb and Ta, m = 3, 4 or 5, wherein the mass ratio of the heteropoly acid: solid obtained in step (1): water is 0.02-0.2:1:5-50; (3) adding a processing aid to the solid obtained in step (2) and mixing to shape the mixture, then performing a third drying; (4) calcining the solid obtained in step (3); (5) mixing the solid obtained in step (4) with a carbon source solution to perform a hydrothermal reaction, performing solid-liquid separation and washing, and then performing a fourth drying; (6) obtaining the catalyst after high-temperature calcination of the solid obtained in step (5) in a carbon-containing atmosphere.

2. The production method according to claim 1, wherein The carbon source comprises one or more of glucose, chitosan, glycogen, cellulose, oligosaccharide, starch and lignin.

3. The method of claim 1 or 2, wherein, The catalyst carrier is a sol-forming aluminum oxide.

4. The method of claim 1 or 2, wherein, The water vapor treatment is performed using a mixed gas of water vapor and a carrier gas, the carrier gas comprises one or more of nitrogen, helium and argon, and the water vapor in the mixed gas is 5%-30% by volume.

5. The method of claim 1 or 2, wherein, In step (3), the processing aid comprises a binder and a lubricant, and the mass ratio of the solid obtained in step (2): binder: lubricant is 1: 0.01-0.1: 0.01-0.

05.

6. The method of claim 1 or 2, wherein, The mass ratio of the carbon source: solid obtained in step (4): water is 0.01-0.1: 1: 10-30.

7. The method of claim 1 or 2, wherein, The heteroatom of the heteropoly acid comprises W or Mo. 8.A hydrodehalogenation catalyst prepared by the method according to any one of claims 1-7. 9.A method for hydrodehalogenation of a halogenated organic compound, the method performing a reaction using the hydrodehalogenation catalyst according to claim 8, wherein the halogenated organic compound is a chlorinated aromatic compound. 10.A hydrodehalogenation product prepared by the method according to claim 9.

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