O-chlorobenzonitrile production method and production line

Abstract

The invention discloses an o-chlorobenzonitrile production method and a production line, and belongs to the technical field of preparation of o-chlorobenzonitrile. The production method of o-chlorobenzonitrile comprises the following steps: (1) raw material pretreatment: mixing o-chlorotoluene with a surfactant and a dispersing aid, and adding the mixture into a high-speed shearing dispersion machine for treatment to obtain an o-chlorotoluene microemulsion; (2) introducing the o-chlorotoluene microemulsion, ammonia gas and air into an ammoxidation reaction kettle filled with a composite catalyst, reacting for 0.5-1 hour under the action of the composite catalyst, and after the reaction is finished, carrying out rectification separation to obtain a crude product of o-chlorobenzonitrile; and (3) washing, filtering and drying the o-chlorobenzonitrile crude product to obtain the o-chlorobenzonitrile. O-chlorotoluene is pretreated to form o-chlorotoluene microemulsion, ammoxidation reaction is carried out under the action of a composite catalyst, then rectification separation, washing and drying are carried out, o-chlorobenzonitrile is obtained, the production method is simple in step, the raw material conversion rate and the product yield are effectively improved, and application and popularization are facilitated.

Description

TECHNICAL FIELD

[0001] The application relates to an o-chlorobenzonitrile production method and production line and belongs to the technical field of o-chlorobenzonitrile preparation. BACKGROUND

[0002] O-chlorobenzonitrile is an important fine chemical and organic preparation intermediate. O-chlorobenzonitrile can be used to prepare corresponding o-chlorobenzeneamine, o-chloroaniline, o-fluorobenzonitrile, o-fluorobenzoic acid, o-fluoroaniline and the like, and is widely applied to the dye, medicine, pesticide and perfume industries. O-chlorobenzonitrile is also an important intermediate for preparing the new antimalarial drug nitroquine and various anti-inflammatory and bactericidal drugs, and is used for preparing non-peptide type anti-angiotensin.

[0003] There are various synthesis methods of o-chlorobenzonitrile. The most simple and advanced method for preparing o-chlorobenzonitrile is the direct ammonia oxidation process of o-chlorotoluene developed and matured in the past three decades. In recent years, the process has developed rapidly due to its short process flow, simple operation and good product quality. Since the chlorine atom at the ortho position of the methyl group of o-chlorotoluene has relatively large steric hindrance and passivation, the ammonia oxidation reaction of o-chlorotoluene is more difficult than that of other substituted toluenes, and therefore the selection of the active component and form of the catalyst is crucial.

[0004] A commonly used and effective catalytic system for preparing o-chlorobenzonitrile by the direct ammonia oxidation process of o-chlorotoluene is a vanadium-based catalyst such as a V-P, V-Cr and Sb-Fe system, which usually uses alumina, silicon carbide or silicon oxide as a carrier and adopts a fixed bed or coarse particle baffle sulfidation bed process. However, the product yield of these processes is not very high.

[0005] Chinese patent CN 103539701 B provides a method for preparing o-chlorobenzonitrile by ammonia oxidation. By using a fluidized bed catalyst with silica as a carrier, the problems of low product yield and small reaction load are solved to a certain extent. However, in the patent, o-chlorotoluene, ammonia and air are directly added to a fluidized bed ammonia oxidation reactor, and therefore the raw material conversion rate and product yield need to be further improved.

[0006] Therefore, it is an important research topic to provide an o-chlorobenzonitrile production method and production line to improve the conversion rate of o-chlorotoluene and the yield of o-chlorobenzonitrile. SUMMARY

[0007] In order to solve the above problems, an o-chlorobenzonitrile production method and production line are provided. The o-chlorobenzonitrile production method is characterized by the following steps: pretreating o-chlorotoluene to form an o-chlorotoluene microemulsion, performing ammonia oxidation reaction under the action of a composite catalyst, and then performing rectification separation, washing and drying to obtain o-chlorobenzonitrile. The production method has simple steps, effectively improves the raw material conversion rate and product yield, and is convenient for popularization and application.

[0008] According to one aspect of the present application, a production method of chloroneb is provided, comprising the following steps:

[0009] (1) Raw material pretreatment: mixing o-chlorotoluene with a surfactant and a dispersion aid, and adding into a high-speed shearing disperser to obtain an o-chlorotoluene microemulsion;

[0010] (2) Passing the o-chlorotoluene microemulsion, ammonia gas and air into an ammonia oxidation reactor, which is filled with a composite catalyst, and reacting for 0.5-1 h under the action of the composite catalyst, and obtaining a crude chloroneb after separation;

[0011] (3) Washing, filtering and drying the crude chloroneb to obtain chloroneb.

[0012] Specifically, the present application uses a surfactant and a dispersion aid to pretreat o-chlorotoluene to form an o-chlorotoluene microemulsion, so that the o-chlorotoluene is uniformly dispersed in the system formed by the surfactant and the dispersion aid in the form of microdroplets, greatly increasing the contact area of o-chlorotoluene with ammonia gas and air, and compared with directly adding o-chlorotoluene, ammonia gas and air to react, the reaction rate can be accelerated while the reaction is more uniform, reducing the occurrence of side reactions due to local overheating and reducing the generation of by-products.

[0013] Specifically, in the present application, the o-chlorotoluene microemulsion, ammonia gas and air are subjected to an ammonia oxidation reaction under the action of the composite catalyst, which can effectively improve the raw material conversion rate and product yield, and the reaction steps are simple, the process flow is short, and the application is convenient.

[0014] Optionally, the surfactant comprises a cationic gemini surfactant and an anionic surfactant, the dispersion aid comprises n-butanol or isopropyl alcohol, the mass ratio of the cationic gemini surfactant to the anionic surfactant is 1:(1-1.5), and the mass ratio of the o-chlorotoluene, the surfactant and the dispersion aid is 1:(0.1-0.2):(0.05-0.1).

[0015] The cationic gemini surfactant comprises two hydrophilic groups and two hydrophobic groups, has stronger surface tension reducing capacity than common single-chain cationic surfactants, and can promote the formation of the microemulsion with o-chlorotoluene as an oil phase substance. However, if the amount of the cationic surfactant is too small, the microemulsion is difficult to form, and if the amount of the cationic surfactant is too large, on the one hand, the cationic surfactant covers the active sites of the catalyst, inhibits the reaction, affects the catalytic efficiency, and further affects the conversion rate of the raw material and the yield of the product; on the other hand, the large amount of the cationic surfactant also changes the viscosity of the reactants, affects the uniform distribution of the reactants, and further causes the local concentration of the reactants to be too high or too low, triggers side reactions, produces more by-products, and reduces the selectivity of the product. Therefore, the anionic surfactant is added to cooperate with the cationic gemini surfactant in the present application. The anionic surfactant has a negative charge and can interact with the cationic surfactant through electrostatic attraction to form an ion pair, avoid the excessive cationic gemini surfactant from covering the active sites of the catalyst, and also reduce the viscosity of the material, reduce the mass transfer resistance, make the reactants uniformly distributed, and reduce the generation of by-products.

[0016] Specifically, the composition and ratio of the surfactants are specifically defined in the present application. The cationic gemini surfactant, the anionic surfactant, and the dispersing aid are cooperatively used in a specific ratio. The dispersing aid is inserted into the interface film of the surfactant to adjust the fluidity and curvature of the interface film, reduce the interfacial tension, and promote the formation of the microemulsion. Under the action of the high-speed shearing disperser, the o-chlorotoluene microemulsion is formed.

[0017] Specifically, the rotation speed of the high-speed shearing disperser is 5000-8000 r / min, and the processing time of the high-speed shearing disperser is 10-15 min.

[0018] Specifically, the mass ratio of the o-chlorotoluene, the surfactant, and the dispersing aid is specifically defined in the present application to obtain the uniform o-chlorotoluene microemulsion.

[0019] Optionally, the molecular structure of the cationic gemini surfactant is as formula (1):

[0020]

[0021] The anionic surfactant comprises one or more of sodium dodecyl benzene sulfonate, sodium dioctyl sulfosuccinate, and sodium tetrapolypropylene benzene sulfonate.

[0022] Specifically, the cationic gemini surfactant has high surface activity and can cooperate with the anionic surfactant to form the uniform and stable o-chlorotoluene microemulsion.

[0023] Optionally, the composite catalyst comprises 30-60 parts of metal oxide, 5-10 parts of catalytic aid and 80-100 parts of carrier by weight; the metal oxide comprises V2O5, CrO3 and Co3O4, the catalytic aid comprises one or more of Ce, P and La elements, and the carrier is modified mesoporous carbon.

[0024] Specifically, the composition of the composite catalyst is limited in the application, and the catalytic efficiency and stability of the catalyst are improved by loading the metal oxide and the catalytic aid on the specific carrier.

[0025] Specifically, the catalytic aid is added in the application, which is beneficial to improve the selectivity of the catalyst, inhibit the occurrence of side reactions, and enhance the thermal stability and structural stability of the catalyst.

[0026] Optionally, the preparation method of the modified mesoporous carbon comprises the following steps: placing mesoporous carbon in concentrated nitric acid, refluxing at 80-120℃ for 4-6h, then washing to neutral and drying to obtain the modified mesoporous carbon.

[0027] Specifically, the mesoporous carbon is modified in the application, on the one hand, the mesoporous carbon itself has a large specific surface area and rich pore structure, which can provide a large number of active component loading sites, which is beneficial to the diffusion and adsorption of reactants and accelerates the catalytic efficiency; on the other hand, under the strong oxidizing action of nitric acid, carboxyl, hydroxyl, carbonyl and other oxygen-containing functional groups are introduced on the surface of the mesoporous carbon, which can be used as anchoring sites for metal ions, thereby enhancing the interaction between the metal oxide and the mesoporous carbon, improving the loading amount and dispersion of the metal oxide, and further accelerating the catalytic efficiency.

[0028] Specifically, the pore size of the mesoporous carbon is 5-10nm, and the specific surface area is 1000-2000m 2 / g.

[0029] Optionally, in step (2), the molar ratio of o-chlorotoluene, ammonia and air is 1:(4-6):(12-16), and the reaction temperature is 320-400℃.

[0030] Specifically, the molar ratio of o-chlorotoluene, ammonia and air is limited in the application, if the content of air is low, the catalytic activity is low, and if the content of air is too high, deep oxidation occurs, and the product yield and selectivity are reduced.

[0031] Optionally, in the metal oxide, the molar ratio of V2O5, CrO3 and Co3O4 is (2-4):(2-2.5):(1-1.2).

[0032] Specifically, V2O5 has good redox performance, can provide suitable active centers, promote the reaction between o-chlorotoluene and ammonia and air, and help to oxidize methyl to nitrile group; CrO3 can adjust the electronic structure and surface acidity of the catalyst, help to improve the oxidation performance of the catalyst, and synergize with V2O5 to enhance the adsorption and activation capacity of the reactants, thereby improving the reaction efficiency; Co3O4 can synergize with V2O5 and CrO3 to improve the stability and activity of the catalyst, and promote the ammonia oxidation reaction.

[0033] Specifically, the preparation method of the composite catalyst comprises the following steps:

[0034] S1, configuration of metal oxide precursor: respectively weigh the corresponding mass of ammonium metavanadate, chromic anhydride and cobalt nitrate, add an appropriate amount of mixed solution of deionized water and anhydrous ethanol, the volume ratio of deionized water to anhydrous ethanol is 1:1, and stir and dissolve at 60-80℃ to form a uniform metal oxide precursor solution;

[0035] S2, configuration of catalyst additive precursor solution: weigh one or more of cerous nitrate, ammonium dihydrogen phosphate and lanthanum nitrate, and add to deionized water, and stir and dissolve at room temperature to prepare a catalyst additive precursor solution;

[0036] S3, place the modified mesoporous carbon in the metal oxide precursor solution, immerse for 20-24h at room temperature, then add the catalyst additive precursor solution, immerse for 6-10h, filter, wash and dry to obtain a composite catalyst precursor;

[0037] S4, transfer the composite catalyst precursor to a muffle furnace, heat to 400-600℃ at an air atmosphere and a heating rate of 2-5℃ / min, and keep for 3-6h;

[0038] S5, then place it in a mixed gas of ammonia and air, activate at 200-250℃ for 30-60min to obtain a composite catalyst.

[0039] According to another aspect of the present application, a o-chlorobenzonitrile production line is also provided, which adopts the above-mentioned o-chlorobenzonitrile production method, and comprises a raw material pretreatment unit, a material storage unit, an ammonia oxidation reaction kettle, a separation unit and a refining unit;

[0040] The raw material pretreatment unit comprises a high-speed shearing disperser, and the o-chlorotoluene is treated with a surfactant and a dispersion aid by the high-speed shearing disperser to obtain an o-chlorotoluene microemulsion;

[0041] The material storage unit comprises an ammonia gas storage tank, an air storage tank and an o-chlorotoluene microemulsion storage tank, the o-chlorotoluene microemulsion storage tank is communicated with the high-speed shearing disperser, and is used for storing the o-chlorotoluene microemulsion;

[0042] The ammonia storage tank, the air storage tank and the o-chlorotoluene microemulsion storage tank respectively deliver ammonia, air and o-chlorotoluene microemulsion to the ammonia oxidation reaction kettle, and the ammonia oxidation reaction kettle is provided with a discharge port.

[0043] Specifically, the raw material pretreatment unit, the material storage unit, the ammonia oxidation reaction kettle, the separation and purification unit are arranged, so that the continuous industrial production of o-chloronitrobenzene can be realized, and the production efficiency is improved.

[0044] Specifically, the raw material pretreatment unit includes a high-speed shearing disperser, and under the action of a surfactant and a dispersion aid, o-chlorotoluene microemulsion is obtained by high-speed shearing of the high-speed shearing disperser, and the o-chlorotoluene microemulsion is delivered to the o-chlorotoluene microemulsion storage tank for storage.

[0045] Specifically, the ammonia storage tank, the air storage tank and the o-chlorotoluene microemulsion storage tank respectively deliver ammonia, air and o-chlorotoluene microemulsion to the ammonia oxidation reaction kettle, and the ammonia oxidation reaction kettle is provided with a discharge port.

[0046] Optionally, the separation unit includes a rectification tower and a ceramic membrane separation device, and the rectification tower and the ceramic membrane separation device are communicated to separate and purify o-chloronitrobenzene.

[0047] Specifically, the rectification tower and the ceramic membrane separation device are combined, on the one hand, light component impurities and heavy component impurities with large differences in boiling points are preliminarily separated by rectification, and o-chloronitrobenzene is enriched in the middle part of the rectification tower; on the other hand, o-chloronitrobenzene molecules can pass through the ceramic membrane, while the remaining impurities with similar boiling points are intercepted, so that the yield and purity of o-chloronitrobenzene are improved.

[0048] Optionally, in the ceramic membrane separation device, the average pore size of the ceramic membrane is 1-2 nm, and the operating pressure is 0.5-1 MPa.

[0049] Specifically, the material to be separated and purified enters the ceramic membrane separation device, and under the cross-flow filtration mode, o-chloronitrobenzene molecules can pass through the ceramic membrane, while the remaining impurities with similar boiling points are intercepted, and the material passing through the membrane is collected, that is, o-chloronitrobenzene is obtained.

[0050] The beneficial effects of the present application include but are not limited to:

[0051] 1. A method for producing o-chlorobenzoitrile according to the present application, which comprises the steps of: pretreating o-chlorotoluene to form an o-chlorotoluene microemulsion, performing an ammoxidation reaction under the action of a composite catalyst, and then performing steps of rectification, separation, washing, drying, etc. to obtain o-chlorobenzoitrile, wherein the production method has simple steps, effectively improves the conversion rate of raw materials and the yield of products, and is convenient for popularization and application.

[0052] 2. A method for producing o-chlorobenzoitrile according to the present application, which comprises the steps of: pretreating o-chlorotoluene with a surfactant and a dispersing aid to form an o-chlorotoluene microemulsion, increasing the contact area of o-chlorotoluene with ammonia and air, accelerating the reaction rate, and making the reaction more uniform, thereby reducing the occurrence of side reactions due to local overheating and reducing the generation of by-products.

[0053] 3. A method for producing o-chlorobenzoitrile according to the present application, which comprises the steps of: synergistically cooperating cationic gemini surfactants and anionic surfactants in a specific ratio, and cooperating with a dispersing aid to promote the formation of a microemulsion, and under the action of a high-speed shearing disperser, forming an o-chlorotoluene microemulsion.

[0054] 4. A method for producing o-chlorobenzoitrile according to the present application, which comprises the steps of: using modified mesoporous carbon as a carrier, which has a large specific surface area and rich pore structure on one hand, and can provide a large number of active component loading sites; on the other hand, the surface of the modified mesoporous carbon is introduced with carboxyl, hydroxyl, carbonyl and other oxygen-containing functional groups, which can act as anchoring sites for metal ions, enhance the interaction between metal oxides and mesoporous carbon, improve the loading capacity and dispersity of metal oxides, and be beneficial to the diffusion and adsorption of reactants, thereby accelerating the catalytic efficiency.

[0055] 5. An o-chlorobenzoitrile production line according to the present application, which has a short process flow and can realize continuous industrial production, thereby greatly improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0056] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0057] Figure 1 FIG. 1 is a schematic diagram of an o-chlorobenzoitrile production line according to the present application.

[0058] List of components and reference numerals:

[0059] 1. high-speed shearing disperser; 2. o-chlorotoluene microemulsion storage tank; 3. air storage tank; 4. ammonia storage tank; 5. ammoxidation reactor; 6. separation unit; 7. refining unit. DETAILED DESCRIPTION

[0060] The application will be described in detail below with reference to the examples, but the application is not limited to these examples.

[0061] The raw materials in the examples and comparative examples of the present application are commercially available unless otherwise specified.

[0062] The methods used in the examples and comparative examples of the present application are conventional methods in the prior art unless otherwise specified. The pore size of the mesoporous carbon is 8 nm, and the specific surface area is 1500 m 2 / g.

[0063] The preparation method of the cationic gemini surfactant involved in the examples and comparative examples of the present application is as follows:

[0064] (1) 20 g of laurylamine and 3 g of sodium carbonate were dissolved in a three-necked flask containing 300 ml of DMF;

[0065] (2) 21 g of 3-bromopropionyl chloride was diluted with 100 ml of DMF;

[0066] (3) Under stirring at 150 rpm, (2) was slowly added to (1), and the dropping speed was controlled so that the temperature of the system was not higher than 45℃;

[0067] (4) After the addition of the 3-bromopropionyl chloride solution was completed, the stirring was continued for 1 h, and the solution after the reaction was transferred to a rotary evaporator, and was evaporated under vacuum at 90℃ to remove the solvent and the remaining bromopropionyl chloride, and the intermediate product 3-bromo-N-dodecylpropanamide was separated;

[0068] (5) 300 ml of isopropyl alcohol was added to a three-necked flask fixed in a water bath, and the product in (4) and 6.5 g of 1,3-bis(dimethylamino)propanediol were added to the three-necked flask, and the stirring was carried out at a speed of 30 rpm and at 60℃ for 15 h under reflux;

[0069] (6) The solvent in the solution after the reaction in (5) was removed in a rotary evaporator at 90℃, and the product was recrystallized twice with a mixed solvent of ethyl acetate and ethanol (20:1), and was dried at 60℃ for 24 h.

[0070] The molecular structure formula of the cationic gemini surfactant prepared by the above method is as follows:

[0071]

[0072] Example 1

[0073] A production method of chlorobonamide:

[0074] (1) raw material pretreatment: mixing o-chlorotoluene with surfactant and dispersion aid, adding into a high-speed shearing disperser for treatment, rotating speed 5000 r / min, treating for 10 min, to obtain o-chlorotoluene microemulsion; wherein the surfactant includes cationic gemini surfactant and sodium dodecylbenzenesulfonate, the mass ratio of the two is 1:1, the dispersion aid is n-butanol, the mass ratio of o-chlorotoluene, surfactant and dispersion aid is 1:0.1:0.05;

[0075] (2) passing o-chlorotoluene microemulsion, ammonia gas and air into an ammonia oxidation reaction kettle, the molar ratio of o-chlorotoluene, ammonia gas and air is 1:4:12, the ammonia oxidation reaction kettle is filled with a composite catalyst, under the action of the composite catalyst, reacting at 320℃ for 0.5h, after the reaction is completed, o-chlorobenzonitrile crude product is obtained by rectification separation; wherein the composite catalyst includes 30 parts of metal oxide, 5 parts of Ce element and 80 parts of modified mesoporous carbon, wherein the metal oxide is V2O5, CrO3 and Co3O4 with a molar ratio of 2:2:1;

[0076] (3) washing, filtering and drying o-chlorobenzonitrile crude product to obtain o-chlorobenzonitrile;

[0077] The preparation method of the composite catalyst in step (2) is as follows:

[0078] S1 configuration of metal oxide precursor: according to the above-mentioned molar ratio of metal oxide, the corresponding mass of ammonium metavanadate, chromium anhydride and cobalt nitrate is weighed, and a mixed solution of appropriate amount of deionized water and anhydrous ethanol is added, the volume ratio of deionized water to anhydrous ethanol is 1:1, stirring and dissolving at 60℃ to form a uniform metal oxide precursor solution;

[0079] S2 preparation of catalyst aid precursor solution: the corresponding cerium nitrate is weighed and added to deionized water, and stirred and dissolved at room temperature to prepare a catalyst aid precursor solution;

[0080] S3 placing mesoporous carbon in concentrated nitric acid, refluxing at 80℃ for 4h, then washing to neutral and drying to obtain modified mesoporous carbon, placing the modified mesoporous carbon in the metal oxide precursor solution, immersing at room temperature for 20h, then adding the catalyst aid precursor solution, immersing for 6h, filtering, washing and drying to obtain a composite catalyst precursor;

[0081] S4 transferring the composite catalyst precursor to a muffle furnace, heating to 400℃ at an air atmosphere with a heating rate of 2℃ / min, and keeping for 3h;

[0082] S5 then placing it in a mixed gas of ammonia and air, activating at 200℃ for 30min to obtain a composite catalyst.

[0083] Example 2

[0084] A method for producing chlorobenzoanitrile:

[0085] (1) Raw material pretreatment: mixing o-chlorotoluene with a surfactant and a dispersion aid, adding into a high-speed shearing disperser, treating at a speed of 8000 r / min for 15 min to obtain an o-chlorotoluene microemulsion; wherein the surfactant includes a cationic gemini surfactant and sodium dioctyl sulfosuccinate, the mass ratio of the two is 1:1.5, the dispersion aid is isopropanol, and the mass ratio of o-chlorotoluene, the surfactant and the dispersion aid is 1:0.2:0.1;

[0086] (2) Passing the o-chlorotoluene microemulsion, ammonia gas and air into an ammonia oxidation reaction kettle, the molar ratio of o-chlorotoluene, ammonia gas and air is 1:6:16, the ammonia oxidation reaction kettle is filled with a composite catalyst, reacting at a temperature of 400℃ for 1h under the action of the composite catalyst, and o-chlorobenzoanitrile crude product is obtained by rectification separation after the reaction is completed; wherein the composite catalyst includes 60 parts of metal oxide, 10 parts of P element and 100 parts of modified mesoporous carbon, and the metal oxide is V2O5, CrO3 and Co3O4 with a molar ratio of 4:2.5:1.2;

[0087] (3) Washing, filtering and drying the o-chlorobenzoanitrile crude product to obtain o-chlorobenzoanitrile;

[0088] The preparation method of the composite catalyst in step (2) is as follows:

[0089] S1 Preparation of metal oxide precursor: according to the above-mentioned molar ratio of metal oxide, the corresponding mass of ammonium metavanadate, chromium anhydride and cobalt nitrate is weighed, and a mixed solution of appropriate amount of deionized water and anhydrous ethanol is added, the volume ratio of deionized water to anhydrous ethanol is 1:1, stirring and dissolving at 80℃ to form a uniform metal oxide precursor solution;

[0090] S2 Preparation of catalyst additive precursor solution: the corresponding ammonium dihydrogen phosphate is weighed and added to deionized water, and stirred and dissolved at room temperature to prepare a catalyst additive precursor solution;

[0091] S3 Placing the mesoporous carbon in concentrated nitric acid, refluxing at 120℃ for 6h, then washing to neutral and drying to obtain modified mesoporous carbon, placing the modified mesoporous carbon in the metal oxide precursor solution, immersing at room temperature for 24h, then adding the catalyst additive precursor solution, immersing for 10h, filtering, washing and drying to obtain a composite catalyst precursor;

[0092] S4 Transferring the composite catalyst precursor to a muffle furnace, heating to 600℃ at a heating rate of 5℃ / min under air atmosphere, and keeping for 6 hours;

[0093] S5Then it is placed in a mixed gas of ammonia and air, activated at 250℃ for 60min, to obtain the composite catalyst.

[0094] Example 3

[0095] A method for producing chloroneb:

[0096] (1) Raw material pretreatment: o-chlorotoluene is mixed with a surfactant and a dispersion aid, and is treated in a high-speed shearing disperser at a speed of 6000r / min for 15min to obtain an o-chlorotoluene microemulsion; wherein the surfactant comprises a cationic gemini surfactant and sodium dodecylbenzenesulfonate, and the mass ratio of the two is 1:1.2, the dispersion aid is n-butanol, and the mass ratio of o-chlorotoluene, surfactant and dispersion aid is 1:0.1:0.1;

[0097] (2) The o-chlorotoluene microemulsion, ammonia and air are introduced into an ammoxidation reactor, and the molar ratio of o-chlorotoluene, ammonia and air is 1:5:15. The ammoxidation reactor is filled with a composite catalyst. Under the action of the composite catalyst, the reaction is carried out at 350℃ for 1h. After the reaction is completed, o-chloroneb crude product is obtained by rectification separation; wherein the composite catalyst comprises 50 parts of metal oxide, 8 parts of La element and 90 parts of modified mesoporous carbon, and the metal oxide is V2O5, CrO3 and Co3O4 in a molar ratio of 3:2:1;

[0098] (3) The o-chloroneb crude product is washed, filtered and dried to obtain o-chloroneb;

[0099] The preparation method of the composite catalyst in step (2) is as follows:

[0100] S1 Preparation of metal oxide precursor: according to the above-mentioned molar ratio of metal oxide, the corresponding mass of ammonium metavanadate, chromic anhydride and cobalt nitrate is weighed, and a mixed solution of appropriate amount of deionized water and anhydrous ethanol is added, the volume ratio of deionized water to anhydrous ethanol is 1:1, and the mixture is stirred and dissolved at 70℃ to form a uniform metal oxide precursor solution;

[0101] S2 Preparation of catalyst additive precursor solution: the corresponding lanthanum nitrate is weighed and added to deionized water, and the mixture is stirred and dissolved at room temperature to prepare a catalyst additive precursor solution;

[0102] S3 The mesoporous carbon is placed in concentrated nitric acid and refluxed at 100℃ for 5h, then washed to neutral and dried to obtain modified mesoporous carbon. The modified mesoporous carbon is placed in the metal oxide precursor solution, immersed at room temperature for 22h, then the catalyst additive precursor solution is added and immersed for 8h, and then filtered, washed and dried to obtain a composite catalyst precursor;

[0103] S4 transfers the composite catalyst precursor into a muffle furnace, heats to 500℃ at a temperature increasing rate of 5℃ / min under air atmosphere, and keeps for 5 hours;

[0104] S5 then places it in a mixed gas of ammonia and air, activates at 220℃ for 40min, to obtain the composite catalyst.

[0105] Example 4

[0106] Example 4 differs from Example 3 in that the amount of surfactant is unchanged, only anionic surfactant is used, and the rest is the same.

[0107] Example 5

[0108] Example 5 differs from Example 3 in that the amount of surfactant is unchanged, only cationic gemini surfactant is used, and the rest is the same.

[0109] Example 6

[0110] Example 6 differs from Example 3 in that the mass ratio of cationic gemini surfactant to anionic surfactant is 1:0.5, and the rest is the same.

[0111] Example 7

[0112] Example 7 differs from Example 3 in that non-ionic surfactant polyoxyethylene alkyl ether is used instead of anionic surfactant, and the rest is the same.

[0113] Example 8

[0114] Example 8 differs from Example 3 in that the composite oxidant does not include catalytic aids, and the rest is the same.

[0115] Example 9

[0116] Example 9 differs from Example 3 in that the amount of catalytic aids in the composite catalyst is 15 parts, and the rest is the same.

[0117] Example 10

[0118] Example 10 differs from Example 3 in that MO2O3 is used instead of CrO3 in the composite catalyst, and the rest is the same.

[0119] Example 11

[0120] Example 11 differs from Example 3 in that the catalytic aid is Pr element, and the rest is the same.

[0121] Example 12

[0122] Example 12 differs from Example 3 in that the molar ratio of metal oxides V2O5, CrO3 and Co3O4 is 1:1:1, and the rest is the same.

[0123] Example 13

[0124] Example 13 differs from Example 3 in that the unmodified mesoporous carbon is used instead of the modified mesoporous carbon, and the rest is the same.

[0125] Example 14

[0126] Example 14 differs from Example 3 in that the silica is used as the carrier instead of the modified mesoporous carbon, and the rest is the same.

[0127] Comparative Example 1

[0128] Comparative Example 1 differs from Example 3 in that the step of pretreatment of raw materials is not included, and the rest is the same.

[0129] Comparative Example 2

[0130] Comparative Example 2 differs from Example 3 in that the dispersing aid is not included in step (1), and the rest is the same.

[0131] Experimental Example 1

[0132] The yield, purity, selectivity of o-chlorobenzonitrile and the conversion rate of o-chlorotoluene prepared by Examples 1-14 and Comparative Examples 1-2 are tested and calculated, wherein the yield of o-chlorobenzonitrile (%) = the number of moles of o-chlorobenzonitrile generated / the number of moles of o-chlorotoluene fed; the selectivity of o-chlorobenzonitrile (%) = the number of moles of o-chlorobenzonitrile generated / the number of moles of o-chlorotoluene reacted; the conversion rate of o-chlorotoluene (%) = the number of moles of o-chlorotoluene reacted / the number of moles of o-chlorotoluene fed. The results are shown in Table 1.

[0133] The selectivity of o-chlorobenzonitrile (%) indicates the proportion of o-chlorotoluene that is successfully converted into the target product o-chlorobenzonitrile among all the o-chlorotoluene participating in the reaction, reflecting the selectivity or specificity of the reaction, i.e., the degree to which the reaction tends to generate the target product rather than by-products; the conversion rate of o-chlorotoluene (%) indicates the proportion of o-chlorotoluene that is truly involved in the reaction, used to measure the utilization rate of the reactant.

[0134] Table 1

[0135]

[0136] From Table 1, it can be seen that Examples 1-3 all have good raw material conversion and product yield, and Example 3 is the best. In Example 7, the type of surfactant is changed, and the yield and selectivity of o-chloronitrile decrease significantly; in Example 10, the type of metal oxide in the composite catalyst is changed, and the conversion of o-chlorotoluene and the yield of o-chloronitrile both decrease to different degrees; in Comparative Example 1, the raw material is not pretreated, and the conversion of o-chlorotoluene, the yield of o-chloronitrile and the selectivity of o-chloronitrile all decrease to different degrees; in Comparative Example 2, no dispersing aid is added, which affects the formation of the microemulsion in the pretreatment process, and thus adversely affects the yield of o-chloronitrile.

[0137] As shown in Figure 1 The raw material pretreatment unit of the present application includes a high-speed shearing disperser 1, under the action of surfactants and dispersing aids, o-chlorotoluene microemulsion is obtained by high-speed shearing of the high-speed shearing disperser 1, and the o-chlorotoluene microemulsion is transported to an o-chlorotoluene microemulsion storage tank 2 for storage; an ammonia gas storage tank 4, an air storage tank 3 and the o-chlorotoluene microemulsion storage tank 2 respectively transport ammonia gas, air and o-chlorotoluene microemulsion to an ammonia oxidation reaction kettle 5, the ammonia oxidation reaction kettle 5 is provided with a discharge port, after the ammonia gas, air and o-chlorotoluene microemulsion are subjected to ammonia oxidation reaction in the ammonia oxidation reaction kettle 5, the reacted material is discharged from the ammonia oxidation reaction kettle 5 through the discharge port, and the material discharged from the discharge port is sequentially subjected to separation and purification in a separation unit 6 and a purification unit 7 to obtain o-chloronitrile.

[0138] The above only describes the embodiments of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. The present application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the technical idea and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing o-chlorobenzonitrile, characterized in that, The following steps are involved: (1) Raw material pretreatment: o-chlorotoluene is mixed with a surfactant and a dispersing aid, and the mixture is added to a high-speed shear disperser to obtain an o-chlorotoluene microemulsion; (2) introducing o-chlorotoluene microemulsion, ammonia, and air into an ammonia oxidation reactor filled with a composite catalyst, reacting for 0.5 to 1 hour under the action of the composite catalyst, and obtaining a crude o-chlorobenzonitrile by separation after the reaction is completed; (3) washing, filtering, and drying the crude o-chlorobenzonitrile to obtain o-chlorobenzonitrile.

2. The production method of o-chlorobenzonitrile according to claim 1, wherein The surfactant includes a cationic gemini surfactant and an anionic surfactant, and the dispersing aid includes n-butanol or isopropanol; the mass ratio of the cationic gemini surfactant to the anionic surfactant is 1:(1-1.5); the mass ratio of o-chlorotoluene, surfactant and dispersing aid is 1:(0.1-0.2):(0.05-0.1).

3. The production method of o-chlorobenzonitrile according to claim 2, wherein The molecular structure of the cationic gemini surfactant is as follows: The anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dioctyl sulfosuccinate, and sodium tetrapropylenebenzenesulfonate.

4. The production method of o-chlorobenzonitrile according to claim 1, wherein The composite catalyst comprises, by weight, 30 to 60 parts of metal oxide, 5 to 10 parts of catalytic promoter and 80 to 100 parts of carrier; the metal oxide comprises V2O5, CrO3 and Co3O4, the catalytic promoter comprises one or more of Ce, P and La elements, and the carrier is modified mesoporous carbon.

5. The method for producing o-chlorobenzonitrile according to claim 4, wherein The preparation method of the modified mesoporous carbon comprises: placing the mesoporous carbon in concentrated nitric acid, refluxing at 80-120° C. for 4-6 hours, then washing to neutrality and drying to obtain the modified mesoporous carbon.

6. The method for producing o-chlorobenzonitrile according to claim 1, wherein In step (2), the molar ratio of o-chlorotoluene, ammonia and air is 1:(4-6):(12-16); and the reaction temperature is 320-400°C.

7. The method for producing o-chlorobenzonitrile according to claim 4, wherein In the metal oxide, the molar ratio of V2O5, CrO3 and Co3O4 is (2-4): (2-2.5): (1-1.2).

8. An o-chlorobenzonitrile production line, characterized in that, The method for producing o-chlorobenzonitrile according to any one of claims 1 to 7 comprises a raw material pretreatment unit, a material storage unit, an ammoxidation reactor, a separation unit and a refining unit; The raw material pretreatment unit includes a high-speed shear disperser, and the o-chlorotoluene, surfactant, and dispersing aid are processed by the high-speed shear disperser to obtain an o-chlorotoluene microemulsion; The material storage unit includes an ammonia storage tank, an air storage tank and an o-chlorotoluene microemulsion storage tank, and the o-chlorotoluene microemulsion storage tank is connected to a high-speed shear disperser for storing o-chlorotoluene microemulsion; The ammonia storage tank, air storage tank and o-chlorotoluene microemulsion storage tank respectively transport ammonia, air and o-chlorotoluene microemulsion to the ammonia oxidation reactor. The ammonia oxidation reactor is provided with a discharge port, and the material discharged from the discharge port passes through the separation unit and the refining unit in sequence.

9. A kind of o-chlorobenzonitrile production line according to claim 8, characterized in that, The separation unit comprises a distillation tower and a ceramic membrane separation device, and the distillation tower is connected to the ceramic membrane separation device for separating and purifying o-chlorobenzonitrile.

10. A kind of o-chlorobenzonitrile production line according to claim 9, characterized in that, In the ceramic membrane separation device, the average pore size of the ceramic membrane is 1 to 2 nm, and the operating pressure is 0.5 to 1 MPa.

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