A catalyst for the preparation of 4,4'-dichlorobenzophenone by heterogeneous catalysis, and a preparation method and application thereof

Abstract

The application discloses a catalyst for preparing 4,4'-dichlorobenzophenone by heterogeneous catalysis, and the catalyst is a composite metal oxide, which is represented as Co a M b O x , wherein the M is any one of nickel, iron, copper, zinc, zirconium and cerium, b:a = 1-20, and the x is the number of oxygen atoms required to satisfy the oxidation states of the metal elements Co and M. Meanwhile, the application also discloses a preparation method of the catalyst and application of the catalyst. When the catalyst is used for catalyzing oxidation of 4,4'-dichlorodiphenylmethane to prepare 4,4'-dichlorobenzophenone, as a heterogeneous catalyst, the catalyst can realize high-efficiency oxidation conversion of 4,4'-dichlorodiphenylmethane, has high catalytic activity, the product is easy to separate, the catalyst can be repeatedly used, and the number of times of repeated use is high.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of 4,4'-dichlorobenzophenone preparation, and particularly relates to a catalyst for preparing 4,4'-dichlorobenzophenone by heterogeneous catalysis, and a preparation method and application thereof. BACKGROUND

[0002] Polyether ether ketone is an important organic chemical material, which has excellent comprehensive performance such as high temperature resistance, self-lubrication and corrosion resistance. It is initially used in the field of national defense and military industry, and then gradually expands to the field of civil use. In the future, with the expansion of China's industrial scale, especially the development of new energy vehicle light weight, integrated circuit life extension, bone repair and other fields, the demand for polyether ether ketone will further increase, which will also drive the market demand for its key monomer 4,4'-difluorobenzophenone.

[0003] At present, the main synthesis routes of 4,4'-difluorobenzophenone which have been industrialized or have industrialization prospect mainly include the following: benzene compound condensation method, catalytic carbonylation method, dichloroethylene oxidation method, catalytic acylation method and diazotization method. Among them, the raw material acyl halide of benzene compound condensation method is expensive, which affects the economy. The dichloroethylene oxidation method has high yield and good product quality, but the raw material is difficult to obtain, the waste acid corrodes the equipment, and causes environmental pollution. The total yield of the catalytic acylation method is only 6%, and the raw material phosgene is toxic, which is difficult to use and control. The diazotization method has the problems of explosion danger of diazonium salt and equipment corrosion.

[0004] Patent CN113321574A discloses a technical route for synthesizing 4,4'-difluorobenzophenone from chlorobenzene and 4-chlorobenzyl chloride through three steps of Friedel-Crafts alkylation, oxidation and fluorination. The route has certain advantages such as cheap and easily available raw materials, simple and easy-to-control process operation. The second step is a homogeneous catalytic oxidation method for preparing 4,4'-dichlorobenzophenone from 4,4'-dichlorodiphenylmethane using manganese compounds as catalysts. Although this method has the advantages of mild reaction conditions and simple synthesis route, the catalysts used are Mn(OAc)3·2H2O, Mn(OAc)2·2H2O, Mn(OAc)2·4H2O, MnSO4·4H2O and MnCl2·4H2O, etc. Manganese-based catalysts, which have difficulties in catalyst recovery and utilization in the later stage, and difficulties in product separation and purification. Patent CN113304759A discloses a heterogeneous catalyst for preparing benzophenone from diphenylmethane by catalytic oxidation, in which cobalt and manganese are supported on a γ-Al2O3 carrier. Diphenylmethane is oxidized under solvent-free conditions to obtain benzophenone, which has high conversion rate and product selectivity.

[0005] The mechanism of methylene oxidation is free radical mechanism, which needs to activate C-H bond. When electron-withdrawing group chlorine atom is introduced into benzene ring, the electron density of benzene ring is reduced, and the oxidation of methylene in conjugated benzyl position is more difficult. The existing technology cannot well catalyze the oxidation of 4,4'-dichlorodiphenylmethane. Therefore, it is necessary to develop a catalyst with high activity and high selectivity for 4,4'-dichlorodiphenylmethane raw material and a catalytic oxidation process method. SUMMARY

[0006] In view of the defects of the prior art, the present application provides a catalyst for the preparation of 4,4'-dichlorodiphenylmethane by heterogeneous catalysis and a preparation method thereof. Meanwhile, the present application also provides a method for preparing 4,4'-dichlorodiphenylmethane by catalyzing the oxidation of 4,4'-dichlorodiphenylmethane with the catalyst, which can realize the efficient oxidation conversion of 4,4'-dichlorodiphenylmethane to prepare 4,4'-dichlorodiphenylmethane, and the product is easy to separate, and the catalyst can be reused.

[0007] A catalyst for the preparation of 4,4'-dichlorodiphenylmethane by heterogeneous catalysis, the catalyst is a composite metal oxide, represented as Co a M b O x , wherein M is any one of nickel, iron, copper, zinc, zirconium and cerium, wherein b:a=1-20, and x is the number of oxygen atoms required to satisfy the oxidation state of metal elements Co and M.

[0008] A preparation method of the catalyst for the preparation of 4,4'-dichlorodiphenylmethane by heterogeneous catalysis, comprising the following steps:

[0009] (1) dissolving a soluble salt containing cobalt and a soluble salt of metal M in water, stirring until clear to obtain solution A;

[0010] (2) dissolving a precipitating agent in water, stirring until clear to obtain solution B;

[0011] (3) adding solution B dropwise to solution A at 50-90°C, controlling the pH value of the system in the range of 8-12, and stirring for 4-12h for co-precipitation reaction;

[0012] (4) centrifuging, washing with deionized water until the solid product is neutral, drying and calcining to obtain the heterogeneous catalyst Co a M b O x .

[0013] Preferably, the concentration of cobalt in solution A is 0.1-2mol / L.

[0014] More preferably, the concentration of cobalt in solution A is 0.1-1mol / L.

[0015] Preferably, the precipitant is one or more of (NH4)2CO3, NH4HCO3, Na2CO3, NaHCO3, NaOH, KOH; the concentration of the solution B is 1-50 mol / L.

[0016] More preferably, the concentration of the solution B is 1-10 mol / L.

[0017] Preferably, the drying condition is drying at 100-110℃ for 8-12h, and the calcination condition is calcination at 500-550℃ for 3-6h.

[0018] A method for preparing 4,4'-dichlorobenzophenone by heterogeneous catalytic oxidation of 4,4'-dichlorodiphenylmethane, specifically as follows: respectively adding raw material 4,4'-dichlorodiphenylmethane and the catalyst into a stainless steel reaction kettle, adding a solvent, closing the kettle, introducing an oxygen-containing gas, heating and stirring to react, after the reaction is completed, cooling to room temperature, adding the solvent to dissolve the reaction product, filtering the catalyst, and collecting the filtrate.

[0019] Preferably, the amount of the catalyst is 1-50% of the mass of 4,4'-dichlorodiphenylmethane. More preferably, the amount of the catalyst is 5-15% of the mass of 4,4'-dichlorodiphenylmethane.

[0020] The solvent is at least one of acetonitrile, cyclohexane, ethanol, and methanol. More preferably, the solvent is at least one of acetonitrile and cyclohexane.

[0021] Preferably, the heating and stirring reaction condition is stirring at 60-200℃ for 6-48h. More preferably, stirring at 120-180℃ for 10-18h.

[0022] The oxygen-containing gas is oxygen or air, and the oxygen partial pressure in the oxygen-containing gas is 0.5-3.0MPa.

[0023] The recycling method of the catalyst, after the catalytic oxidation of 4,4'-dichlorodiphenylmethane to prepare 4,4'-dichlorobenzophenone, the recovered catalyst is washed with the solvent for 3-5 times, and then dried and calcined, so as to be recycled; wherein the drying and calcination conditions are the same as the drying and calcination conditions in the preparation process of the catalyst.

[0024] Advantages of the present application:

[0025] The catalyst provided by the application can realize high-efficiency oxidative conversion of 4,4'-dichlorobenzyl alcohol containing inert groups, has high catalytic activity, and the product is easy to separate, the catalyst can be reused, and the number of reuse is high. Embodiment

[0026] Example 1

[0027] 1. A heterogeneous catalyst for preparing 4,4'-dichlorobenzophenone, wherein the catalyst is a composite metal oxide represented as Co2Ni 10 O 13 , and the molar ratio of Ni to Co is 5.

[0028] 2. A preparation method of the heterogeneous catalyst for preparing 4,4'-dichlorobenzophenone, comprising the following steps:

[0029] (1) 10 mmol of Co(NO3)2·6H2O and 50 mmol of Ni(NO3)2·6H2O are dissolved in 50 mL of water, and stirred until clear to obtain solution A;

[0030] (2) A (NH4)2CO3 solution with a concentration of 2 mol / L is prepared, and stirred until clear to obtain solution B;

[0031] (3) Solution B is slowly added dropwise to solution A at 80°C, the pH of the system is controlled at 10, and stirring is performed for 10 h for a coprecipitation reaction;

[0032] (4) After the reaction is completed, centrifugation is performed, and the solid product is washed with deionized water until neutral, dried at 105°C for 8 h, and calcined at 500°C for 6 h to obtain the heterogeneous catalyst.

[0033] Example 2

[0034] 1. A heterogeneous catalyst for preparing 4,4'-dichlorobenzophenone, wherein the catalyst is a composite metal oxide represented as CoZn 10 O 11 , and the molar ratio of Zn to Co is 10.

[0035] 2. A preparation method of the heterogeneous catalyst for preparing 4,4'-dichlorobenzophenone, comprising the following steps:

[0036] (1) 5 mmol of Co(NO3)2·6H2O and 50 mmol of Zn(NO3)2·6H2O are dissolved in 50 mL of water, and stirred until clear to obtain solution A;

[0037] (2) Preparation of a 10 mol / L NH4HCO3solution, stirring until clear, to obtain solution B;

[0038] (3) Slow dropwise addition of solution B to solution A at 50°C, controlling the pH of the system at 10, stirring for 12 h for co-precipitation reaction;

[0039] (4) After the reaction, centrifugation, washing with deionized water until the solid product is neutral, drying at 100°C for 12 h, and calcination at 550°C for 3 h to obtain a heterogeneous catalyst.

[0040] Example 3

[0041] 1. A heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, said catalyst being a composite metal oxide represented as Co2Zr2O7, the molar ratio of Zr to Co being 1.

[0042] 2. A method for the preparation of the heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, comprising the following steps:

[0043] (1) Dissolution of 10 mmol Co(NO3)2·6H2O and 10 mmol Zr(NO3)4·5H2O in 20 mL of water, stirring until clear, to obtain solution A;

[0044] (2) Preparation of a 1 mol / L Na2CO3solution, stirring until clear, to obtain solution B;

[0045] (3) Slow dropwise addition of solution B to solution A at 90°C, controlling the pH of the system at 10, stirring for 4 h for co-precipitation reaction;

[0046] (4) After the reaction, centrifugation, washing with deionized water until the solid product is neutral, drying at 110°C for 8 h, and calcination at 550°C for 4 h to obtain a heterogeneous catalyst.

[0047] Example 4

[0048] 1. A heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, said catalyst being a composite metal oxide represented as CoCe 20 O 31 , the molar ratio of Ce to Co being 20.

[0049] 2. A method for the preparation of the heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, comprising the following steps:

[0050] (1) Dissolution of 5 mmol Co(NO3)2·6H2O and 100 mmol Ce(NO3)3·6H2O in 20 mL of water, stirring until clear, to obtain solution A;

[0051] (2) A solution of NaHCO3 with a concentration of 10 mol / L was prepared and stirred until clear to obtain solution B;

[0052] (3) Solution B was slowly added dropwise to solution A at 60°C, the pH of the system was controlled at 8, and the co-precipitation reaction was stirred for 6 h;

[0053] (4) After the reaction was completed, centrifugation was performed, the solid product was washed with deionized water until neutral, and drying was performed at 105°C for 8 h and calcination was performed at 550°C for 4 h to obtain a heterogeneous catalyst.

[0054] Example 5

[0055] 1. A heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, the catalyst being a composite metal oxide represented as CoFeO3, the molar ratio of Fe to Co being 1.

[0056] 2. A method for the preparation of the heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, comprising the following steps:

[0057] (1) 20 mmol of Co(NO3)2·6H2O and 20 mmol of Fe(NO3)3·9H2O were dissolved in 20 mL of water, and stirring was performed until clear to obtain solution A;

[0058] (2) A solution of NaOH with a concentration of 2 mol / L was prepared and stirred until clear to obtain solution B;

[0059] (3) Solution B was slowly added dropwise to solution A at 60°C, the pH of the system was controlled at 10, and the co-precipitation reaction was stirred for 6 h;

[0060] (4) After the reaction was completed, centrifugation was performed, the solid product was washed with deionized water until neutral, and drying was performed at 105°C for 8 h and calcination was performed at 550°C for 4 h to obtain a heterogeneous catalyst.

[0061] Example 6

[0062] 1. A heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, the catalyst being a composite metal oxide represented as CoCu2O 3.5 , the molar ratio of Cu to Co being 2.

[0063] 2. A method for the preparation of the heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, comprising the following steps:

[0064] (1) 10 mmol Co (NO3)2·6H2O and 20 mmol Cu (NO3)2·3H2O were dissolved in 10 mL water, stirred until clear, to obtain solution A;

[0065] (2) A 2 mol / L KOH solution was prepared, stirred until clear, to obtain solution B;

[0066] (3) Solution B was slowly added dropwise to solution A at 60°C, the pH of the system was controlled at 12, and the coprecipitation reaction was stirred for 6 h;

[0067] (4) After the reaction was completed, centrifugation was performed, and the solid product was washed with deionized water until neutral, dried at 105°C for 8 h, and calcined at 550°C for 4 h, to obtain a heterogeneous catalyst.

[0068] I. Catalytic performance detection

[0069] A method for preparing 4,4'-dichlorobenzophenone by heterogeneous catalytic oxidation of 4,4'-dichlorodiphenylmethane: 1.2 g of raw material 4,4'-dichlorodiphenylmethane and a catalyst were respectively added to a stainless steel reaction kettle, a solvent was added, the kettle was closed, an oxygen-containing gas was introduced, the oxygen partial pressure in the oxygen-containing gas was 0.5-3.0 MPa, and the reaction was stirred at 60-200°C for 6-48 h, and then cooled to room temperature. The product was dissolved by adding a solvent, the catalyst was recovered by filtration, the filtrate was collected, and the reaction results were analyzed by gas chromatography. The reaction conditions and results are shown in Table 1.

[0070] Table 1. Reaction conditions and results

[0071]

[0072] II. Detection of recycling performance

[0073] The catalyst of Example 1 was recovered after the above catalytic oxidation for preparing 4,4'-dichlorobenzophenone was completed, washed with acetonitrile for 3 times, dried in an oven at 105°C for 8 h, and calcined at 500°C for 6 h, to obtain a recycled catalyst. The recycling performance of the catalyst was evaluated according to the same reaction conditions of the catalyst of Example 1. After each reaction, the catalyst was recycled and treated in the same way. The reaction results are shown in Table 2.

[0074] Table 2. Recycling reaction results

[0075]

[0076] It can be seen that the catalyst obtained by the present application has slightly reduced catalytic performance after being recycled for 10 times, but the catalytic performance is still good.

Claims

1. A process for the heterogeneously catalyzed oxidation of 4,4'-dichlorodiphenylmethane to 4,4'-dichlorobenzophenone, characterized in that: The raw material 4,4'-dichlorodiphenyl methane and a catalyst are respectively added into a stainless steel reaction kettle, a solvent is added, the kettle is closed, an oxygen-containing gas is introduced, heating and stirring reaction is carried out, after the reaction is completed, the reaction product is dissolved by adding the solvent, the catalyst is filtered, and the filtrate is collected; wherein the catalyst is a composite metal oxide represented by Co a M b O x , the M is any one of nickel, iron, copper, zinc, zirconium, cerium, wherein b:a = 1-20, and the x is the number of oxygen atoms required to satisfy the oxidation states of the metal elements Co and M.

2. The process according to claim 1 for the preparation of 4,4'-dichlorobenzophenone by the heterogeneous catalytic oxidation of 4,4'-dichlorodiphenylmethane, characterized in that: The catalyst is prepared by the following method: (1) a soluble salt containing cobalt and a soluble salt of metal M are dissolved in water, stirring until clear, to obtain solution A; (2) a precipitant is dissolved in water, stirring until clear, to obtain solution B; (3) solution B is added dropwise to solution A at 50-90℃, the pH value of the system is controlled in the range of 8-12, and stirring is carried out for 4-12h for co-precipitation reaction; (4) Centrifugation, washing with deionized water until the solid product is neutral, drying, calcination, to obtain a heterogeneous catalyst Co a M b O x .

3. The process according to claim 2 for the preparation of 4,4'-dichlorobenzophenone by the heterogeneous catalytic oxidation of 4,4'-dichlorodiphenylmethane, characterized in that: In the solution A, the concentration of cobalt is 0.1-2mol / L.

4. The process according to claim 3 for the preparation of 4,4'-dichlorobenzophenone by the heterogeneous catalytic oxidation of 4,4'-dichlorodiphenylmethane, characterized in that: The precipitant is at least one of (NH4)2CO3, NH4HCO3, Na2CO3, NaHCO3, NaOH, KOH; the concentration of the solution B is 1-50mol / L.

5. The process according to claim 4 for the preparation of 4,4'-dichlorobenzophenone by the heterogeneous catalytic oxidation of 4,4'-dichlorodiphenylmethane, characterized in that: The drying condition is drying at 100-110℃ for 8-12h, and the calcination condition is calcination at 500-550℃ for 3-6h.

6. The process according to claim 1 for the catalytic oxidation of 4,4'- dichlorobenzylidene in the presence of a heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, characterized in that: The solvent is at least one of acetonitrile, cyclohexane, ethanol, and methanol.

7. The process according to claim 6 for the preparation of 4,4'-dichlorobenzophenone by the heterogeneous catalytic oxidation of 4,4'-dichlorodiphenylmethane, characterized in that: The amount of the catalyst is 1-50% of the mass of 4,4'-dichlorodiphenyl methane.

8. The process according to claim 1 for the catalytic oxidation of 4,4'- dichlorobenzylidene in the presence of a heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, characterized in that: The heating and stirring reaction condition is stirring reaction at 60-200℃ for 6-48h.

9. The process according to claim 8 for the catalytic oxidation of 4,4'- dichlorobenzylidene in the presence of a heterogeneous catalyst for the preparation of 4,4'-dichlorobenzophenone, characterized in that: The oxygen-containing gas is oxygen or air, and the oxygen partial pressure in the oxygen-containing gas is 0.5-3.0MPa.

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