Continuous hydrodechlorination catalyst and preparation method thereof

Abstract

The invention relates to a continuous hydrodechlorination catalyst and a preparation method thereof. Provided is a hydrodechlorination catalyst, the catalyst comprising: a carrier comprising a first metal complex and a second metal complex, the first metal being selected from Group IIIA, IIIB, IVB, and VB metal elements of the periodic table of elements, the second metal being selected from Group VIB, VIIB, VIIIB, IB, and IIB metal elements of the periodic table of elements; a catalytically active metal supported on the support, wherein the catalyst is treated with phosphoric acid.

Description

Technical Field

[0001] The present application relates to the field of catalysts, and in particular, to a polychlorinated benzene selective hydrodechlorination catalyst and a preparation method thereof. Background Art

[0002] Polychlorinated aromatic compounds are extremely harmful to the environment due to their inherent difficulty in degradation and harmfulness. In addition, the value and market demand of polychlorinated aromatic compounds are often low, and most of the industrial treatment methods for these polychlorinated aromatic compounds are solid waste treatment. If polychlorinated aromatic compounds with no industrial use can be removed by appropriate means to turn them into useful low-chlorinated compounds, it will help solid waste treatment, save corporate costs, and achieve the concept of green production.

[0003] At present, the common hydrodechlorination catalysts are mainly Pd, Pt, Rh and Ni catalysts. Compared with Ni-based catalysts, precious metal catalysts have higher activity and stability under mild conditions, among which Pd catalysts have better hydrodechlorination performance.

[0004] CN110407663A discloses a method for synthesizing dichlorobenzene, using Pd / C as a catalyst and trichlorobenzene as a substrate, and successfully preparing dichlorobenzene by hydrodechlorination in a kettle reactor. However, the kettle technology used requires the use of a large amount of alkali, which is not conducive to safe production and the reduction of equipment costs. CN111233621B discloses a method for treating dichlorobenzene distillation residue, wherein the Pd catalyst can selectively hydrodechlorinate polychlorobenzenes to benzene through a fixed bed reactor, which has a low added value and still has room for further selectivity improvement.

[0005] On the other hand, in the hydrodechlorination process of the tubular reactor, due to the lack of absorption of alkali, the generated HCl makes the stability of the catalyst problematic. In addition, different catalysts also have problems of metal loss and sintering due to their own structures. The Pt / spinel catalyst used in US4827057A has a stable operation time of 2000h for the hydrogenation of polychlorinated benzenes, but its dechlorination product composition is relatively complex, which is not conducive to further application.

[0006] As can be seen from the above, the currently described catalysts still have problems with selectivity and stability for the selective hydrogenation of polychlorinated benzene compounds. Therefore, it is necessary to develop an efficient and stable catalyst to hydrodechlorinate polychlorinated benzene compounds to designated products (such as m-dichlorobenzene and p-dichlorobenzene with higher added value) with a long service life, thereby reducing costs for enterprises and achieving green production. Summary of the invention

[0007] The purpose of the present application is to provide an efficient and stable catalyst for hydrodechlorinating polychlorinated benzene compounds to designated products (such as m-dichlorobenzene and p-dichlorobenzene with higher added value) with a long service life, thereby reducing costs for enterprises and achieving green production.

[0008] On the one hand, the present application provides a hydrodechlorination catalyst, the catalyst comprising:

[0009] A carrier, the carrier comprising a first metal complex and a second metal complex, the first metal being selected from metal elements of Groups IIIA, IIIB, IVB and VB of the Periodic Table, and the second metal being selected from metal elements of Groups VIB, VIIB, VIIIB, IB and IIB of the Periodic Table;

[0010] The catalytically active metal is supported on a carrier.

[0011] The catalyst is treated with phosphoric acid.

[0012] On the other hand, the present application provides a method for preparing a hydrodechlorination catalyst, the method comprising the following steps:

[0013] (1) providing a carrier, the carrier comprising a first metal complex and a second metal complex, the first metal being selected from metal elements of Groups IIIA, IIIB, IVB and VB of the Periodic Table, and the second metal being selected from metal elements of Groups VIB, VIIB, VIIIB, IB and IIB of the Periodic Table;

[0014] (2) loading a catalytically active metal on the carrier; and

[0015] (3) Treating the support loaded with catalytically active metal with phosphoric acid to obtain the catalyst.

[0016] On the other hand, the present application provides a method for hydrodechlorination of polychlorinated benzenes, the method comprising the following steps:

[0017] (1) providing the hydrodechlorination catalyst described in the present application; and

[0018] (2) Using the catalyst to selectively hydrodechlorinate polychlorinated benzenes. DETAILED DESCRIPTION

[0019] "Scope" disclosed herein is defined in the form of lower limit and upper limit, 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 boundary of a particular range. The scope defined in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a particular parameter, it is understood that the scope of 60-110 and 80-120 is also expected. 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 scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0020] In this application, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution.

[0021] In this application, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0022] In the present application, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0023] In this application, unless otherwise specified, the terms "include" and "comprising" mentioned herein may be open-ended or closed-ended. For example, the terms "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0024] In the description of this article, it should be noted that, unless otherwise specified, "above" and "below" are inclusive of the number itself, and "several" in "one or several" means two or more.

[0025] 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 satisfies 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).

[0026] Herein, unless otherwise specified, percentage (%) or part refers to percentage by weight or part by weight relative to the composition.

[0027] Herein, if there is no contrary description, the sum of the contents of the various components in the composition is 100%.

[0028] Herein, if there is no contrary description, the sum of the parts of each component in the composition may be 100 parts by weight.

[0029] In this context, unless otherwise specified, "a combination thereof" means a multi-component mixture of the elements described, for example a mixture of two, three, four and up to the maximum possible multi-component mixture.

[0030] If not specifically stated, the terms "a" or "an" used in the present specification means "at least one".

[0031] Herein, unless otherwise stated, all reactions are carried out at normal temperature and pressure.

[0032] As used herein, the term "metal" may refer to a metal element or a metal ion.

[0033] On the one hand, the present application provides a hydrodechlorination catalyst, the catalyst comprising:

[0034] A carrier, the carrier comprising a first metal complex and a second metal complex, the first metal being selected from metal elements of Groups IIIA, IIIB, IVB and VB of the Periodic Table, and the second metal being selected from metal elements of Groups VIB, VIIB, VIIIB, IB and IIB of the Periodic Table;

[0035] The catalytically active metal is supported on a carrier.

[0036] The catalyst is treated with phosphoric acid.

[0037] In one example of the present application, the metal elements of Group IIIA of the Periodic Table include but are not limited to Al, Ga, In, Tl or a combination thereof; the metal elements of Group IIIB of the Periodic Table include but are not limited to Sc, Y, lanthanide rare earth elements (including but not limited to lanthanum, cerium, praseodymium, neodymium or a combination thereof) or actinide rare earth elements (including but not limited to actinium); the metal elements of Group IVB of the Periodic Table include but are not limited to Ti, Zr, Hf or a combination thereof; the metal elements of Group VB of the Periodic Table include but are not limited to V, Nb, Ta or a combination thereof; the metal elements of Group VIB of the Periodic Table include but are not limited to Cr, Mo, W or a combination thereof; the metal elements of Group VIIB of the Periodic Table include but are not limited to Mn, Re or a combination thereof; the metal elements of Group VIIIB of the Periodic Table include but are not limited to Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt or a combination thereof; the metal elements of Group IB of the Periodic Table include but are not limited to Cu, Ag, Au or a combination thereof; the metal elements of Group IIB of the Periodic Table include but are not limited to Zn, Cd, Hg or a combination thereof. In one example of the present application, the first metal is different from the second metal.

[0038] In an example of the present application, the first metal complex and the second metal complex represent a complex formed by the first metal or the second metal (usually in the form of metal ions) and a complexing agent. The complexing agent can be a complexing agent commonly used in the art, including but not limited to phosphorus-containing complexing agents, alcohol amine complexing agents, hydroxycarboxylic acid complexing agents, polyacrylic acid complexing agents, aminocarboxylic acid complexing agents. In a preferred embodiment of the present application, the complexing agent is a phosphorus-containing complexing agent, such as phosphoric acid or organic phosphonic acid, including but not limited to phytic acid, aminotrimethylenephosphonic acid, nitrotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, diethylenetriamine pentamethylphosphonic acid, aminotrimethylphosphonic acid, methylene diphosphonic acid or a combination thereof.

[0039] In one example of the present application, the molar ratio of the first metal complex to the second metal complex is 1:0.01-0.5, such as 1:0.02-0.4, 1:0.05-0.2.

[0040] In one example of the present application, based on the total weight of the catalyst, the content of the second metal (in pure metal form) is 0.5-25 wt%, such as 1-20 wt%, 3-15 wt%.

[0041] In one example of the present application, the carrier may also include additives for shaping, including but not limited to a binder, a lubricant, or a combination thereof. In one example of the present application, the binder may be a binder commonly used in the art, and its function is to shape the components of the carrier. Commonly used binders include but are not limited to one or more of polyvinyl alcohol, animal glue, molasses, sodium carboxymethyl cellulose, aluminum phosphate, and silicate cement. In one example of the present application, the lubricant may be a lubricant commonly used in the art. Commonly used lubricants include but are not limited to one or more of stearic acid, sodium stearate, paraffin, sesbania powder, polyethylene wax, and zinc stearate.

[0042] In one example of the present application, based on the total weight of the carrier, the additive is used in an amount of 1%-40%, such as 2%-35%, 3%-30%.

[0043] In one example of the present application, the carrier may have a shape known in the art, including but not limited to, columnar (eg, cylindrical), trilobal, quadrilobal, spherical, cuboid, cube, tetrahedron, and irregular shape.

[0044] In one example of the present application, the catalytically active metal may be an active metal commonly used in the art for catalyzing the hydrodechlorination reaction of polychlorinated benzenes, including but not limited to noble metals such as Pt, Pd, Rh or a combination thereof.

[0045] In one example of the present application, the loading amount of the catalytically active metal is 0.05-5 wt %, preferably 0.1-4 wt %, 0.2-2.0 wt %, based on the total mass of the catalyst.

[0046] In one example of the present application, the phosphorus acid includes but is not limited to phosphoric acid, polyphosphoric acid (such as diphosphoric acid, triphosphoric acid, etc.), metaphosphoric acid, pyrophosphoric acid or a combination thereof.

[0047] In one example of the present application, the treatment means that the support loaded with catalytically active metal is impregnated in a phosphoric acid solution (e.g., aqueous solution). The impregnation can be excessive impregnation, equal volume impregnation, and multiple impregnations, the impregnation temperature is room temperature or heating conditions (e.g., 25-90° C., generally 30-80° C., 40-80° C.), and the impregnation time is 0.5-10 hours (e.g., 1-8 hours, 1-6 hours).

[0048] In one example of the present application, the concentration of the phosphoric acid solution may be a common concentration, such as 1-20% by weight, 2-15% by weight, or 3-10% by weight.

[0049] On the other hand, the present application provides a method for preparing a hydrodechlorination catalyst, the method comprising the following steps:

[0050] (1) providing a carrier, the carrier comprising a first metal complex and a second metal complex, the first metal being selected from metal elements of Groups IIIA, IIIB, IVB and VB of the Periodic Table, and the second metal being selected from metal elements of Groups VIB, VIIB, VIIIB, IB and IIB of the Periodic Table;

[0051] (2) loading a catalytically active metal on the carrier; and

[0052] (3) Treating the support loaded with catalytically active metal with phosphoric acid to obtain the catalyst.

[0053] Provide carrier

[0054] In one example of the present application, the step of providing a carrier may include (1) mixing a solution containing a first metal salt and a second metal salt with a complexing agent to react to obtain a first metal complex and a second metal complex solid product; (2) mixing the solid product obtained in step (1) with an optional additive to form the solid product.

[0055] In one example of the present application, the first metal salt or the second metal salt refers to a salt including the first metal or the second metal, such as nitrate, sulfate, halide (such as chloride, bromide, etc.) or a combination thereof.

[0056] In one example of the present application, the metal elements of Group IIIA of the Periodic Table include but are not limited to Al, Ga, In, Tl or a combination thereof; the metal elements of Group IIIB of the Periodic Table include but are not limited to Sc, Y, lanthanide rare earth elements (including but not limited to lanthanum, cerium, praseodymium, neodymium or a combination thereof) or actinide rare earth elements (including but not limited to actinium); the metal elements of Group IVB of the Periodic Table include but are not limited to Ti, Zr, Hf or a combination thereof; the metal elements of Group VB of the Periodic Table include but are not limited to V, Nb, Ta or a combination thereof; the metal elements of Group VIB of the Periodic Table include but are not limited to Cr, Mo, W or a combination thereof; the metal elements of Group VIIB of the Periodic Table include but are not limited to Mn, Re or a combination thereof; the metal elements of Group VIIIB of the Periodic Table include but are not limited to Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt or a combination thereof; the metal elements of Group IB of the Periodic Table include but are not limited to Cu, Ag, Au or a combination thereof; the metal elements of Group IIB of the Periodic Table include but are not limited to Zn, Cd, Hg or a combination thereof. In one example of the present application, the first metal is different from the second metal.

[0057] In one example of the present application, the complexing agent can be a complexing agent commonly used in the art, including but not limited to phosphorus-containing complexing agents, alcohol amine complexing agents, hydroxycarboxylic acid complexing agents, polyacrylic acid complexing agents, aminocarboxylic acid complexing agents. In a preferred embodiment of the present application, the complexing agent is a phosphorus-containing complexing agent, such as phosphoric acid or organic phosphonic acid, including but not limited to phytic acid, aminotrimethylenephosphonic acid, nitrotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, diethylenetriamine penta-methylenephosphonic acid, aminotrimethylenephosphonic acid, methylene diphosphonic acid or a combination thereof.

[0058] In one example of the present application, the molar ratio of the first metal, the second metal and the complexing agent is 1: 0.01-0.5 (eg, 0.02-0.4, 0.05-0.2): 0.05-2 (eg, 0.1-1.5, 0.2-1).

[0059] In one example of the present application, the optional additives include but are not limited to a binder, a lubricant or a combination thereof. In one example of the present application, the binder may be a binder commonly used in the art, and its function is to shape the components of the carrier. Commonly used binders include but are not limited to one or more of polyvinyl alcohol, animal glue, molasses, sodium carboxymethyl cellulose, aluminum phosphate, and silicate cement. In one example of the present application, the lubricant may be a lubricant commonly used in the art. Commonly used lubricants include but are not limited to one or more of stearic acid, sodium stearate, paraffin, sesbania powder, polyethylene wax, and zinc stearate.

[0060] In one example of the present application, based on the total weight of the carrier, the additive is used in an amount of 1%-40%, such as 2%-35%, 3%-30%.

[0061] In one example of the present application, the carrier may have a shape known in the art, including but not limited to, columnar (eg, cylindrical), trilobal, quadrilobal, spherical, cuboid, cube, tetrahedron, and irregular shape.

[0062] In one example of the present application, the mixing reaction step (1) can be carried out under heating conditions (eg, 25-60° C.) for 6-72 hours.

[0063] In one example of the present application, the solid product obtained in the mixing reaction step (1) can be pre-dried. Usually, the pre-drying temperature is 40-100° C., and the solid-water ratio of the obtained wet solid is controlled to be 1-2.5.

[0064] In one example of the present application, the forming in step (2) may be a forming method commonly used in the art, including but not limited to extrusion forming, molding, and the like.

[0065] In one example of the present application, the shaped carrier may be further dried. The drying includes heating, microwave treatment or a combination thereof. The heating temperature may be 60-140° C. for 4 to 72 hours. The microwave treatment time may be 0.5 to 12 hours at a frequency of 2000-3500 MHz (e.g., 2400 to 2450 MHz).

[0066] In one example of the present application, the carrier may be further calcined in an atmosphere of inert gas (nitrogen, rare gas) or air, at a temperature of 400-600° C., for a time of 2-48 hours.

[0067] The catalytically active metal is loaded on the support

[0068] In one example of the present application, the catalytically active metal may be an active metal commonly used in the art for catalyzing the hydrodechlorination reaction of polychlorinated benzenes, including but not limited to noble metals such as Pt, Pd, Rh or a combination thereof.

[0069] In one example of the present application, the loading amount of the catalytically active metal is 0.05-5 wt %, preferably 0.1-4 wt %, 0.2-2.0 wt %, based on the total mass of the catalyst.

[0070] In the present application, the method of loading the catalytically active metal on the carrier can be a method commonly used in the art, for example, the carrier can be immersed in a solution (such as an aqueous solution) containing a catalytically active metal salt, and then the catalytically active metal salt can be reduced to a catalytically active metal with a reducing agent.

[0071] In one example of the present application, the impregnation can be excessive impregnation, equal volume impregnation and multiple impregnations, the impregnation temperature is room temperature or heating conditions (e.g. 25-90°C, generally 30-80°C, 40-80°C), and the impregnation time is 0.5-10 hours (e.g. 1-8 hours, 1-6 hours).

[0072] In one example of the present application, the catalytically active metal salt refers to a salt including a catalytically active metal, such as a nitrate, a sulfate, a halide (such as a chloride, a bromide, etc.), a complex (such as an acid of an active metal and a salt thereof (such as an ammonium salt, a sodium salt, a potassium salt)) or a combination thereof. In one example of the present application, the complex may be, for example, palladium acid, bromopalladium acid, chloropalladium acid, platinic acid, bromoplatinic acid, chloroplatinic acid, rhodium acid, bromorhodium acid, chlororhodium acid and salts thereof (such as ammonium salts, sodium salts, potassium salts). In one example of the present application, the reducing agent may be a reducing agent commonly used in the art, including but not limited to one or more of sodium borohydride, ascorbic acid, hydrazine hydrate, sodium hypophosphite, and formaldehyde. The mass ratio of the noble metal (based on the noble metal element after reduction) to the reducing agent is not specifically limited, and may be, for example, 1:0.6-6.5 (e.g., 1:0.6-3, 1:1-3).

[0073] Treating a support loaded with catalytically active metals with phosphoric acid

[0074] In one example of the present application, the phosphorus acid includes but is not limited to phosphoric acid, polyphosphoric acid (such as diphosphoric acid, triphosphoric acid, etc.), metaphosphoric acid, pyrophosphoric acid or a combination thereof.

[0075] In one example of the present application, the treatment means that the support loaded with catalytically active metal is impregnated in a phosphoric acid solution (e.g., aqueous solution). The impregnation can be excessive impregnation, equal volume impregnation, and multiple impregnations, the impregnation temperature is room temperature or heating conditions (e.g., 25-90° C., generally 30-80° C., 40-80° C.), and the impregnation time is 0.5-10 hours (e.g., 1-8 hours, 1-6 hours).

[0076] In one example of the present application, the concentration of the phosphoric acid solution may be a common concentration, such as 1-20% by weight, 2-15% by weight, or 3-10% by weight.

[0077] In one embodiment of the present application, the carrier treated with phosphoric acid may be further dried and / or calcined. The drying may be vacuum drying, the drying temperature is 60-140°C, and the time is 4-72 hours. The calcination atmosphere is an inert gas (nitrogen, rare gas) or air, the temperature is 200-400°C, and the time is 2-48 hours.

[0078] On the other hand, the present application provides a method for hydrodechlorination of polychlorinated benzenes, the method comprising the following steps:

[0079] (1) providing the hydrodechlorination catalyst described in the present application; and

[0080] (2) Using the catalyst to selectively hydrodechlorinate polychlorinated benzenes.

[0081] The catalyst described in the present application can be used for selective hydrogenation and dechlorination of polychlorobenzenes. In this article, the "polychlorobenzenes" include one or more of dichlorobenzenes (e.g., 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene), trichlorobenzenes (e.g., 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene), tetrachlorobenzenes (e.g., 1,2,3,4-tetrachlorobenzene, 1,2,3,5-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene), pentachlorobenzene, and hexachlorobenzene. In a preferred embodiment of the present application, the catalyst selectively dechlorinates and hydrogenates polychlorobenzenes (preferably trichlorobenzenes (e.g., 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene or 1,3,5-trichlorobenzene)). Preferably, the catalyst of the present application can selectively dechlorinate and hydrogenate trichlorobenzenes to form dichlorobenzenes, preferably m- and p-dichlorobenzenes.

[0082] In one example of the present application, the content of dichlorobenzene in the dechlorination hydrogenation product (selectivity of dichlorobenzene) is at least 70% by weight, such as 70-99% by weight, preferably 75-99% by weight, and more preferably 80-99% by weight. Preferably, the content of meta- / para-dichlorobenzene is at least 70% by weight, such as 70-95% by weight, preferably 75-95% by weight, and more preferably 80-95% by weight.

[0083] In one example of the present application, the life of the catalyst is at least 3000 hours, for example, 3000-8000 hours, 3000-7000 hours, 3000-6000 hours, 3000-5000 hours.

[0084] In the present application, the conditions for selective hydrodechlorination of polychlorinated benzene using the catalyst can be the hydrodechlorination conditions commonly used in the art. In one example of the present application, the selective hydrodechlorination is generally carried out at a temperature of 60-300°C, such as 80-260°C, 100-240°C, 120-220°C, 140-200°C.

[0085] The beneficial effects of the present invention are:

[0086] 1. The active center of the catalyst has a strong resistance to HCl through the protection of phosphate, and can maintain high stability under hydrodechlorination conditions.

[0087] 2. The carrier is doped with a second element through the action of a chelating agent, which greatly improves the acid resistance of the carrier and improves the stability of the carrier under hydrodechlorination conditions; at the same time, the introduction of the second element adjusts the adsorption configuration of polychlorinated benzenes, further improves the desorption ability of ortho-position chloride ions, improves the selectivity of para-position and meta-position, and improves the economic value of the product.

[0088] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0089] Main reagents for the experiment

[0090] raw material Product Name Manufacturer Cerium nitrate Cerium nitrate Hubei 789 Chemical Industry Co., Ltd. Nickel nitrate Nickel nitrate hexahydrate Hubei Longxin Chemical Industry Co., Ltd. Phytic Acid Phytic Acid Wuhan Jixinyibang Biotechnology Co., Ltd. Polyvinyl alcohol Polyvinyl alcohol Jiangsu Runfeng Synthetic Technology Co., Ltd. paraffin paraffin Jiangsu Runfeng Synthetic Technology Co., Ltd. Sodium chloropalladate Sodium tetrachloropalladate Wuhan Xinzhongxin Chemical Co., Ltd. Sodium borohydride Sodium borohydride Shandong Yinglang Chemical Co., Ltd. Phosphoric acid Phosphoric acid Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0091] Main experimental instruments

[0092] Instrument Name model Manufacturer Fixed bed HF-V1 Shanghai Baikal Technology Micro-wave oven MKX-H1C1A Qingdao Microwave Innovation Technology Co., Ltd. Muffle furnace SGM M25 / 10 Sigma (Shanghai) High Temperature Electric Furnace Co., Ltd.

[0093] Specific test methods used in the examples

[0094] Conversion rate and selectivity testing methods

[0095] The liquid after the reaction was collected and analyzed by Agilent 7890 gas chromatograph. The concentration of each component was calculated by external standard method using hydrogen flame detector (FID).

[0096] Catalyst life (h) refers to the operating time during which the reaction conversion rate and reaction selectivity decay to less than or equal to 80%.

[0097] The catalyst composition was analyzed by ICP test.

[0098] Example 1

[0099] Weigh 90g of 30wt% cerium nitrate aqueous solution, 10g of 15wt% nickel nitrate aqueous solution and 16.4g of phytic acid, control the molar ratio of cerium: nickel: phytic acid to be 1:0.1:0.3, add 100g of water and stir and heat at 40°C for 12h. Pre-dry the filtered and washed solid mixture, control the solid-water ratio to 1, add binder polyvinyl alcohol and lubricant paraffin to the wet solid in a ratio of 1:0.1:0.03 and mix evenly, and extrude the wet material into a cylindrical molded product. Dry the cylindrical molded product at 120°C for 12h, cool it down and take it out, and microwave it in a laboratory microwave oven for 2h at a frequency of 2450MHz. After microwave treatment, heat the obtained solid to 450°C in a muffle furnace and roast it for 12h, and the roasting atmosphere is nitrogen. Immerse the above-mentioned solid in an equal volume of sodium chloropalladate solution containing 1wt% Pd for 4h. After impregnation, each 100g of solid was added to 100g of 5% sodium borohydride solution for reduction, followed by solid-liquid separation. After washing, the solid was immersed in a 5% phosphoric acid solution and heated for 2h at 60°C. After cooling, solid-liquid separation was performed, and the obtained catalyst solid was vacuum dried at 120°C for 24h, then heated to 300°C in a muffle furnace and calcined for 12h for standby use. The Ni content of the obtained catalyst was 2.98wt%, and the Pd content was 0.93wt%.

[0100] Comparative Example 1 (without second element doping)

[0101] The catalyst was prepared in the same manner as in Example 1, except that no nickel nitrate aqueous solution was used.

[0102] Comparative Example 2 (Purchased Commercial Pd / C Catalyst)

[0103] A commercial carbon-based polychlorinated benzene hydrodechlorination catalyst was purchased, and the metal loading was determined by ICP (inductively coupled plasma). The first catalytic component was loaded with 1% of the precious metal Pd. The catalyst was dried in vacuum at 120° C. for 12 h before use.

[0104] Comparative Example 3 (without microwave treatment)

[0105] The catalyst was prepared in the same manner as in Example 1, except that microwave treatment was not used.

[0106] Comparative Example 4 (no phosphoric acid soaking and heating after catalyst reduction)

[0107] The catalyst was prepared in the same manner as in Example 1, except that no 5% phosphoric acid solution was used for soaking.

[0108] Example 2

[0109] Weigh 90g of 30wt% zirconium nitrate aqueous solution, 10g of 10wt% molybdenum nitrate aqueous solution and 7.2g of aminotrimethylphosphonic acid, control the molar ratio of zirconium: molybdenum: aminotrimethylphosphonic acid to be 1:0.1:0.3, add 100g of water and stir and heat at 60°C for 8h, pre-dry the filtered and washed solid mixture, control the solid-water ratio to 1, add binder polyvinyl alcohol and lubricant paraffin in a ratio of 1:0.1:0.03 to the wet solid and mix evenly, and extrude the wet material into a cylindrical molded product. Dry the cylindrical molded product at 120°C for 12h, cool it down and take it out, and microwave it in a laboratory microwave oven for 4h, with a frequency of 2450MHz. After microwave treatment, heat the obtained solid to 450°C in a muffle furnace and roast it for 12h before taking it out, and the roasting atmosphere is nitrogen. Immerse the above-mentioned solid in an equal volume of sodium chloropalladate solution containing 1.5wt% Pd for 6h. After impregnation, each 100g of solid was added to 100g of 10wt% sodium hypophosphite solution for reduction, then washed and immersed in 3% tripolyphosphoric acid for 2h, the heating temperature was 40°C. After cooling, solid-liquid separation was performed, and the obtained catalyst solid was vacuum dried at 120°C for 24h, then heated to 300°C in a muffle furnace under a nitrogen atmosphere for 12h for standby use. The Mo content of the obtained catalyst was 4.57wt%, and the Pd content was 1.46wt%.

[0110] Embodiment 3:

[0111] Weigh 90g of 30wt% zirconium nitrate and aluminum chloride aqueous solution (mass ratio is 7:3), 20g of 25wt% manganese chloride aqueous solution and 16.7g of hydroxyethylidene diphosphonic acid, control the molar ratio of zirconium + aluminum: manganese: hydroxyethylidene diphosphonic acid to be 1:0.1:0.4, add 100g of water and stir and heat at 60℃ for 8h, pre-dry the solid mixture after filtration and washing, control the solid-water ratio to 1, add adhesive animal glue, lubricant stearic acid and water in a ratio of 1:0.15:0.04 to the wet solid and mix evenly, and extrude the wet material into a columnar molded product. Dry the columnar molded product at 120℃ for 12h, cool it down and take it out, heat it to 450℃ in a muffle furnace and roast it for 12h, and then take it out, the roasting atmosphere is air. The above-obtained solid is immersed in an equal volume of chloroplatinic acid solution containing 1wt% Pt for 8h. After impregnation, each 100g of solid was added to 100g of 5% formaldehyde aqueous solution for reduction, then washed and immersed in 10% phosphoric acid for 4h, and the heating temperature was 60°C. After cooling, solid-liquid separation was performed, and the obtained catalyst solid was vacuum dried at 120°C for 24h, then heated to 300°C in a muffle furnace under a nitrogen atmosphere for 12h for standby use. The Mn content of the obtained catalyst was 4.06wt%, and the Pt content was 0.97wt%.

[0112] Embodiment 4:

[0113] Weigh 90g of 30wt% niobium chloride aqueous solution, 20g of aqueous solution with 13wt% cobalt nitrate and 5wt% cadmium nitrate, and 11.96g of aminotrimethylenephosphonic acid, control the molar ratio of niobium: cobalt + cadmium: aminotrimethylenephosphonic acid to be 1:0.2:0.4, add 100g of water and stir and heat at 40°C for 12h, pre-dry the filtered and washed solid mixture, control the solid-water ratio to 1, add binder polyvinyl alcohol, lubricant stearic acid and water in a ratio of 1:0.1:0.03 to the wet solid and mix evenly, and extrude the wet material into a columnar molded product. The columnar molded product is dried at 120°C for 12h, cooled and taken out, and microwaved in a laboratory microwave oven for 4h at a frequency of 2450MHz. After microwave treatment, the obtained solid is heated to 450°C in a muffle furnace and roasted for 12h and then taken out, and the roasting atmosphere is air. The above-obtained solid is immersed in an equal volume of platinum nitrate solution containing 1wt% Pt for 8h. After impregnation, each 100g of solid was added to 100g of 5% formaldehyde aqueous solution for reduction, then washed and immersed in 15% pyrophosphoric acid for 4h, and the heating temperature was 60°C. After cooling, solid-liquid separation was performed, and the obtained catalyst solid was vacuum dried at 120°C for 12h, then heated to 300°C in a muffle furnace under a nitrogen atmosphere for 24h for standby use. The Co content of the obtained catalyst was 5.7wt%, the Cd content was 2.4wt%, and the Pt content was 0.99wt%.

[0114] Embodiment 5:

[0115] Weigh 90g30wt% cerium nitrate aqueous solution, 10g10wt% cadmium nitrate aqueous solution and 5.82g methylene diphosphoric acid, control the molar ratio of cerium: cadmium: methylene diphosphoric acid to be 1:0.05:0.4, add 100g water and stir and heat at 60°C for 8h, pre-dry the filtered and washed solid mixture, control the solid-water ratio to 2.5, add binder sodium carboxymethyl cellulose and lubricant sodium stearate in a ratio of 1:0.2:0.06 to the wet solid and mix evenly, extrude the wet material into a cylindrical molded product, dry the cylindrical molded product at 120°C for 12h, cool it down and take it out, and microwave it in a laboratory microwave oven for 2h, with a frequency of 2450MHz. After microwave treatment, heat the obtained solid to 450°C in a muffle furnace and roast it for 12h, and the roasting atmosphere is nitrogen. The above-mentioned solid is immersed in an equal volume of rhodium trichloride solution containing 0.5wt% Rh for 4h. After impregnation, each 100g of solid was added to 100g of 5% sodium borohydride aqueous solution for reduction, then washed and immersed in 10% phosphoric acid for 6h, and the heating temperature was 30°C. After cooling, solid-liquid separation was performed, and the obtained catalyst solid was vacuum dried at 120°C for 12h, then heated to 200°C in a muffle furnace under a nitrogen atmosphere for 48h for standby use. The Cd content of the obtained catalyst was 6.4wt%, and the Rh content was 0.48wt%.

[0116] Embodiment 6:

[0117] Weigh 90g30wt% cerium nitrate aqueous solution, 10g15wt% copper nitrate aqueous solution and 21.87g phytic acid, control the molar ratio of cerium: copper: phytic acid to be 1:0.1:0.4, add 100g water and stir and heat at 40°C for 12h, pre-dry the filtered and washed solid mixture, control the solid-water ratio to 1, add binder polyvinyl alcohol and lubricant polyethylene wax to the wet solid in a ratio of 1:0.1:0.03 and mix evenly, extrude the wet material into a cylindrical molded product, dry the cylindrical molded product at 140°C for 12h, cool it down and take it out, and microwave it in a laboratory microwave oven for 6h, with a frequency of 2450MHz. After microwave treatment, heat the obtained solid to 450°C in a muffle furnace and roast it for 12h, and the roasting atmosphere is air. The above-mentioned solid is excessively impregnated in a mixed solution (platinum nitrate and palladium nitrate) containing 0.8wt% Pd and Pt (1:1) for 4h. After impregnation, each 100g of solid was added to 100g of 10% ascorbic acid aqueous solution for reduction, then washed and immersed in 8% pyrophosphoric acid for 2h, and the heating temperature was 60°C. After cooling, solid-liquid separation was performed, and the obtained catalyst solid was vacuum dried at 120°C for 24h, then heated to 300°C in a muffle furnace under a nitrogen atmosphere for 12h for standby use. The Cu content of the obtained catalyst was 4.3wt%, the Pd content was 0.36wt%, and the Pt content was 0.33wt%.

[0118] Embodiment 7:

[0119] Weigh 90g30wt% aluminum nitrate aqueous solution, 31g15wt% nickel nitrate aqueous solution and 36.33g diethylene triamine penta methylene phosphoric acid, control aluminum: nickel: diethylene triamine penta methylene phosphoric acid molar ratio of 1: 0.2: 0.5, add 100g water and stir and heat at 25 ° C for 72h, pre-dry the solid mixture after filtration and washing, control the solid-water ratio to 2.5, add binder aluminum phosphate and lubricant zinc stearate in a ratio of 1: 0.2: 0.05 to the wet solid and mix evenly, extrude the wet material into a cylindrical molded product, the cylindrical molded product is dried at 120 ° C for 12h, cooled and taken out, and microwaved in a laboratory microwave oven for 12h, with a frequency of 2450MHz. After microwave treatment, the obtained solid is heated to 450 ° C in a muffle furnace and roasted for 12h, and the roasting atmosphere is air. The above-mentioned solid is excessively impregnated in a chloroplatinic acid solution containing 1wt% Pt for 4h. After impregnation, each 100g of solid was added to 100g of 5wt% hydrazine hydrate aqueous solution for reduction, then washed and immersed in 5% phosphoric acid for 2h, and the heating temperature was 60°C. After cooling, solid-liquid separation was performed, and the obtained catalyst solid was vacuum dried at 120°C for 24h, then heated to 300°C in a muffle furnace under a nitrogen atmosphere for 12h for standby use. The Ni content of the obtained catalyst was 14.3wt%, and the Pt content was 0.95wt%.

[0120] Embodiment 8:

[0121] Weigh 90g of 30wt% cerium nitrate aqueous solution, 10g of 15wt% nickel nitrate aqueous solution and 16.4g of phytic acid, control the molar ratio of cerium: nickel: phytic acid to be 1:0.1:0.3, add 100g of water and stir and heat at 40°C for 12h, pre-dry the filtered and washed solid mixture, control the solid-water ratio to 1, add binder polyvinyl alcohol and lubricant zinc stearate in a ratio of 1:0.1:0.03 to the wet solid and mix evenly, extrude the wet material into a cylindrical molded product, dry the cylindrical molded product at 120°C for 12h, cool it down and take it out, and microwave it in a laboratory microwave oven for 2h, with a frequency of 2450MHz. After microwave treatment, heat the obtained solid to 450°C in a muffle furnace and roast it for 12h, and the roasting atmosphere is nitrogen. The solid obtained above was immersed in a mixed solution (platinum nitrate and palladium nitrate) containing 0.05wt% Pd and Pt (1:1) for 2h. After the impregnation, each 100g of solid was added to 100g of 1wt% sodium borohydride aqueous solution for reduction. After reduction, it was filtered and washed. The impregnation reduction process was repeated 5 times. After washing, it was immersed and heated in 5% tripolyphosphoric acid for 8h, and the heating temperature was 60°C. After cooling, solid-liquid separation was carried out, and the obtained catalyst solid was vacuum dried at 60°C for 24h, and then heated to 360°C in a muffle furnace and calcined in a nitrogen atmosphere for 12h for standby use. The Ni content of the obtained catalyst was 4.1wt%, and the Pt content was 0.23wt%.

[0122] Hydrodechlorination of polychlorinated benzenes:

[0123] The catalysts prepared in the above examples and comparative examples were crushed and sieved, and 10 g of the 10-20 mesh crushed solids were loaded into a fixed bed reactor. 2 Replacement, re-opening H 2 , adjust the bed temperature to 120℃, the bed pressure to 0.1MPa, and the hydrogenation reaction polychlorinated benzene weight hourly space velocity to 0.5h -1 The mass ratio of hydrogen to polychlorinated benzenes was 20:1, 1,2,4-trichlorobenzene raw material was introduced, and a hydrodechlorination reaction occurred in the presence of hydrogen and a catalyst. The reaction liquid after the hydrogenation reaction was collected for GC (gas chromatography) analysis, and the results are listed in the following table.

[0124] Table 1 Comparison of reaction results of catalysts prepared in different embodiments under the above conditions

[0125]

[0126] Example 9

[0127] On the basis of the catalyst prepared in Example 1, a polychlorobenzene mixed solution was introduced as a substrate, and the contents of each component in the polychlorobenzene substrate were: 6.97% of 1,2,3-trichlorobenzene, 24.82% of 1,2,4-trichlorobenzene, 23.28% of 1,3,5-trichlorobenzene; 11.07% of 1,2,3,4-tetrachlorobenzene, 13.32% of 1,2,4,5-tetrachlorobenzene, 6.60% of 1,2,3,5-tetrachlorobenzene, 9.50% of pentachlorobenzene, and 4.44% of hexachlorobenzene. The other reaction conditions of the polychlorobenzene hydrodechlorination were controlled to be the same, and the reaction effect was as follows.

[0128] Example 10

[0129] Under the conditions of Example 9, other conditions were kept the same, and the bed temperature of the hydrodechlorination was changed to 160°C. The reaction results were as follows.

[0130] Table 2 Reaction results of polychlorinated benzene substrates under the same reaction conditions

[0131]

[0132] Examples 11 to 17

[0133] On the basis of the catalyst prepared in Example 1, the reaction parameters of polychlorinated benzene hydrodechlorination were changed, and the substrate was 1,2,4-trichlorobenzene. The reaction effect was as follows:

[0134] Table 3 Reaction results of the same example under different reaction conditions

[0135]

Claims

1. A hydrodechlorination catalyst, comprising: A carrier, the carrier comprising a first metal complex and a second metal complex, the first metal being selected from metal elements of Groups IIIA, IIIB, IVB and VB of the Periodic Table, and the second metal being selected from metal elements of Groups VIB, VIIB, VIIIB, IB and IIB of the Periodic Table; The catalytically active metal is supported on a carrier. The catalyst is treated with phosphoric acid.

2. The catalyst according to claim 1, wherein The metal elements of IIIA of the periodic table include Al, Ga, In, Tl or a combination thereof; The metal elements of Group IIIB of the Periodic Table include Sc, Y, lanthanide rare earth elements or actinide rare earth elements; The metal elements of Group IVB of the Periodic Table include Ti, Zr, Hf or a combination thereof; The metal elements of Group VB of the periodic table include V, Nb, Ta or a combination thereof; The metal elements of Group VIB of the Periodic Table include Cr, Mo, W or a combination thereof; The metal element of Group VIIB of the Periodic Table includes Mn, Re or a combination thereof; The metal elements of Group VIIIB of the Periodic Table include Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt or a combination thereof; The metal elements of the periodic table IB include Cu, Ag, Au or a combination thereof; The metal elements of Group IIB of the Periodic Table include Zn, Cd, Hg or a combination thereof; or The first metal is different from the second metal.

3. The catalyst according to claim 1, wherein The first metal complex and the second metal complex represent a complex formed by the first metal or the second metal and a complexing agent; or The complexing agent includes a phosphorus-containing complexing agent, an alcoholamine complexing agent, a hydroxycarboxylic acid complexing agent, a polyacrylic acid complexing agent, and an aminocarboxylic acid complexing agent; or, The complexing agent is a phosphorus-containing complexing agent, such as phosphoric acid or an organic phosphonic acid; or The complexing agent includes phytic acid, aminotrimethylenephosphonic acid, nitrotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), aminotrimethylenephosphonic acid, methylene diphosphonic acid or a combination thereof; or The molar ratio of the first metal complex to the second metal complex is 1:0.01-0.5, for example, 1:0.02-0.4, 1:0.05-0.2; or, Based on the total weight of the catalyst, the content of the second metal is 0.5-25wt%, such as 1-20wt%, 3-15wt%.

4. The catalyst according to claim 1, wherein The catalytically active metal comprises a noble metal, such as Pt, Pd, Rh or a combination thereof; or, The loading amount of the catalytically active metal is 0.05-5 wt%, preferably 0.1-4 wt%, 0.2-2.0 wt%, based on the total mass of the catalyst; or The phosphorus-containing acid includes phosphoric acid, polyphosphoric acid (such as diphosphoric acid, triphosphoric acid, etc.), metaphosphoric acid, pyrophosphoric acid or a combination thereof.

5. A method for preparing a hydrodechlorination catalyst, the method comprising the following steps: (a) providing a carrier, the carrier comprising a first metal complex and a second metal complex, the first metal being selected from metal elements of Groups IIIA, IIIB, IVB and VB of the Periodic Table, and the second metal being selected from metal elements of Groups VIB, VIIB, VIIIB, IB and IIB of the Periodic Table; (b) supporting a catalytically active metal on the carrier; and (c) treating the support loaded with the catalytically active metal with phosphoric acid to obtain the catalyst.

6. The method of claim 5, wherein: The step of providing a carrier may include (1) mixing a solution containing a first metal salt and a second metal salt with a complexing agent to react to obtain a first metal complex and a second metal complex solid product; (2) mixing the solid product obtained in step (1) with optional additives to form; or, The first metal salt or the second metal salt refers to a salt comprising the first metal or the second metal, such as a nitrate, a sulfate, a halide (such as a chloride, a bromide, etc.) or a combination thereof; or, The metal element of IIIA of the periodic table includes Al, Ga, In, Tl or a combination thereof; or, The metal elements of Group IIIB of the Periodic Table include Sc, Y, lanthanide rare earth elements or actinide rare earth elements; or The metal element of Group IVB of the Periodic Table includes Ti, Zr, Hf or a combination thereof; or The metal elements of Group VB of the periodic table include V, Nb, Ta or a combination thereof; or, The metal elements of Group VIB of the Periodic Table include Cr, Mo, W or a combination thereof; or The metal element of Group VIIB of the Periodic Table includes Mn, Re or a combination thereof; or The metal element of Group VIIIB of the Periodic Table includes Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt or a combination thereof; or The metal element of the periodic table IB includes Cu, Ag, Au or a combination thereof; or, The metal element of Group IIB of the Periodic Table includes Zn, Cd, Hg or a combination thereof; or, The first metal is different from the second metal; or, The complexing agent includes a phosphorus-containing complexing agent, an alcoholamine complexing agent, a hydroxycarboxylic acid complexing agent, a polyacrylic acid complexing agent, and an aminocarboxylic acid complexing agent; or, The complexing agent is a phosphorus-containing complexing agent, such as phosphoric acid or organic phosphonic acid; or, The complexing agent includes phytic acid, aminotrimethylenephosphonic acid, nitrotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), aminotrimethylenephosphonic acid, methylene diphosphonic acid or a combination thereof; or, The molar ratio of the first metal, the second metal and the complexing agent is 1: 0.01-0.5 (e.g. 0.02-0.4, 0.05-0.2): 0.05-2 (e.g. 0.1-1.5, 0.2-1); or, The forming in step (2) includes extrusion forming or molding; or, The shaped carrier is further dried; or, The drying comprises heating, microwave treatment or a combination thereof.

7. The method of claim 5, wherein: The catalytically active metal comprises a noble metal, such as Pt, Pd, Rh or a combination thereof; or, Based on the total mass of the catalyst, the loading amount of the catalytically active metal is 0.05-5wt%, preferably 0.1-4wt%, 0.2-2.0wt%.

8. The method of claim 5, wherein: The phosphorus acid includes phosphoric acid, polyphosphoric acid (such as diphosphoric acid, triphosphoric acid, etc.), metaphosphoric acid, pyrophosphoric acid or a combination thereof; or, The treatment means that the support loaded with the catalytically active metal is immersed in a phosphoric acid-containing solution.

9. A method for hydrodechlorination of polychlorinated benzenes, comprising the following steps: (1) providing a hydrodechlorination catalyst according to any one of claims 1 to 4; as well as (2) Using the catalyst to selectively hydrodechlorinate polychlorinated benzenes.

10. The method of claim 9, wherein: The polychlorinated benzenes include one or more of dichlorobenzene (e.g., 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene), trichlorobenzene (e.g., 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene), tetrachlorobenzene (e.g., 1,2,3,4-tetrachlorobenzene, 1,2,3,5-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene), pentachlorobenzene, and hexachlorobenzene; or, The catalyst selectively dechlorinates and hydrogenates polychlorobenzenes (preferably trichlorobenzenes (such as 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene or 1,3,5-trichlorobenzene)); or The catalyst selectively dechlorinates and hydrogenates trichlorobenzene to form dichlorobenzene, preferably m- and p-dichlorobenzene; or, The dichlorobenzene content (dichlorobenzene selectivity) in the dechlorination hydrogenation product is at least 70% by weight, such as 70-99% by weight, preferably 75-99% by weight, and more preferably 80-99% by weight; or The content of the m- / p-dichlorobenzene in the dechlorination hydrogenation product is at least 70 wt %, such as 70-95 wt %, preferably 75-95 wt %, more preferably 80-95 wt %.

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