Synthesis process of chlorobenzonitrile

Abstract

The invention discloses a synthesis process of o-chlorobenzonitrile, a NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst prepared by the method can better prepare o-chlorotoluene, has the advantages of high selectivity, long service life, mild process conditions and small carbon deposition amount, and has important significance for improving product quality, reducing production cost and promoting green development of the industry.

Description

Technical Field

[0001] The invention relates to a synthesis process of o-chlorobenzonitrile, and belongs to the technical field of organic synthesis. Background Art

[0002] As an important fine chemical intermediate, o-chlorobenzonitrile, with its unique chemical reactivity due to the chlorine and cyano groups in its molecular structure, is widely used in the synthesis of antimicrobial drugs, high-efficiency herbicides, disperse dyes, and liquid crystal materials. With the rapid development of downstream industries, the demand for o-chlorobenzonitrile's purity and production capacity continues to rise, driving the research and improvement of its synthesis process into an industry focus.

[0003] Currently, the synthesis methods of o-chlorobenzonitrile mainly include the following categories: First, o-chloroaniline undergoes a diazotization reaction to form a diazonium salt, which then undergoes a Sandmeyer reaction with cuprous cyanide. Although this method has mild reaction conditions, it requires the use of a highly toxic cyanide reagent, which poses serious safety hazards and produces a large amount of waste liquid containing heavy metals. The environmental treatment cost is high, making it difficult to meet the requirements of modern green chemical industry. Second, o-chlorobenzaldehyde reacts with hydroxylamine to form an oxime, which is then dehydrated with a dehydrating agent (such as acetic anhydride or phosphorus oxychloride) to form o-chlorobenzonitrile. The raw materials for this route are readily available, but the dehydration step is often accompanied by side reactions, resulting in low product yields (usually less than 75%). Excessive use of dehydrating agents also increases the difficulty of subsequent separation and purification and the discharge of three wastes. Third, the o-chlorotoluene ammoxidation method uses o-chlorotoluene, ammonia, and oxygen as raw materials, which are converted into o-chlorobenzonitrile in a single step under the action of a catalyst. This method has become the mainstream choice for industrial production due to its high atom economy and low raw material costs.

[0004] However, the existing o-chlorotoluene ammoxidation process still faces significant technical bottlenecks. Core catalysts are still under continuous exploration. Existing catalysts include Ni-Fe dual-site catalysts, RuO-Cl catalysts, and LaCl3 / Al2O3 catalysts. However, most of these catalysts suffer from uneven distribution of acidic sites, leading to insufficient reaction selectivity (low o-chlorobenzonitrile selectivity). Deep oxidation or dechlorination reactions are prone to produce impurities such as benzonitrile, which not only reduces raw material utilization but also increases energy consumption for product purification. Furthermore, some active catalyst components are prone to deactivation due to carbon deposition or sintering, seriously affecting production continuity and driving up operating costs. Furthermore, the existing process requires stringent control precision for reaction temperature and material ratios. Even slight fluctuations can lead to a surge in byproducts, further limiting the stability and economic viability of industrial plants.

[0005] The present invention aims to provide a synthesis process for o-chlorobenzonitrile, which has high selectivity, a long-life catalyst, mild process conditions, and is easy to industrially control. The synthesis process is of great significance for improving product quality, reducing production costs, and promoting green development of the industry. Summary of the Invention

[0006] The present invention aims to provide a process for synthesizing o-chlorobenzonitrile. The NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst prepared by the process is capable of better preparing o-chlorotoluene, with high o-chlorotoluene conversion, good selectivity, low carbon deposition, and maximum active component stability.

[0007] A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst, with TiO2-CeO2-MgO as the carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 60-80 parts of o-chlorotoluene are placed in a reactor and the temperature is adjusted to 210 degrees Celsius until the o-chlorotoluene begins to vaporize. The vaporized o-chlorotoluene, ammonia, and air are introduced into a fluidized bed reactor containing 5-8 parts of the above-mentioned NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst in a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis is carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0008] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0009] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol Sb2O3, add 500 mL of concentrated hydrochloric acid (37% by mass), heat under reflux until completely dissolved to form a SbCl3 solution, cool and dilute to 1000 mL with deionized water for later use; d. A TiO2-CeO2-MgO support with a Ti:Ce:Mg molar ratio of 9:(0.3-0.5):(0.2-0.3) was prepared by coprecipitation. The required amounts of TiCl4, Ce(NO3)3·6H2O, and Mg(NO3)2·6H2O were dissolved in ultrapure water to form a solution at room temperature. An excess of ammonia was then added to the solution and stirred vigorously until the pH reached 10. The resulting solution was stirred for an additional 3 hours and then allowed to stand for 24 hours. The precipitate was then filtered and washed three times with ultrapure water. The resulting filter cake was dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO2-CeO2-MgO support. After cooling, the support was pulverized through a 20-40 mesh sieve for later use. e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, and 1 / 2 of the mass of the mixed solution is added to the TiO2-CeO2-MgO carrier. Stir and impregnate at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0010] Advantages of the present invention: After years of research and practice, our R&D team has invented a synthesis process for o-chlorobenzonitrile. This o-chlorobenzonitrile synthesis process has high selectivity, a long-life catalyst, mild process conditions, and is easy to industrially control. It is of great significance for improving product quality, reducing production costs, and promoting green development of the industry. DETAILED DESCRIPTION

[0011] The following describes in detail embodiments of the present invention. The embodiments are only used to illustrate the present invention and are not to be construed as limiting the present invention.

[0012] Specific embodiments of the present invention are described below.

[0013] Preparation Example 1 A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst, with TiO2-CeO2-MgO as the carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 60 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius to allow the o-chlorotoluene to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 8 parts of the NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst at a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0014] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0015] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol Sb2O3, add 500 mL of concentrated hydrochloric acid (mass fraction 37%), heat under reflux until completely dissolved to generate SbCl3 solution, cool and dilute to 1000 mL with deionized water for later use; d. A TiO2-CeO2-MgO carrier with a Ti:Ce:Mg molar ratio of 9:0.3:0.2 was prepared by co-precipitation. First, the required amount of TiCl4, Ce(NO3)3·6H2O and Mg(NO3)2·6H2O were dissolved in ultrapure water to form a solution at room temperature. Then, an excess of ammonia water was added to the solution and stirred vigorously until the pH value was 10. The resulting solution was stirred for another 3 hours and then allowed to stand for 24 hours. The precipitate was then filtered and washed three times with ultrapure water; the filter cake was dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO2-CeO2-MgO carrier, which was naturally cooled and crushed through a 20-40 mesh sieve for later use; e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, and 1 / 2 of the mass of the mixed solution is added to the TiO2-CeO2-MgO carrier. Stir and impregnate at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0016] Preparation Example 2 A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst, with TiO2-CeO2-MgO as the carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 70 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius to allow the o-chlorotoluene to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 6 parts of the NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst at a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0017] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0018] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol Sb2O3, add 500 mL of concentrated hydrochloric acid (37% by mass), heat under reflux until completely dissolved to form a SbCl3 solution, cool and dilute to 1000 mL with deionized water for later use; d. A TiO2-CeO2-MgO carrier with a Ti:Ce:Mg molar ratio of 9:0.4:0.3 was prepared by co-precipitation. First, the required amount of TiCl4, Ce(NO3)3·6H2O and Mg(NO3)2·6H2O were dissolved in ultrapure water to form a solution at room temperature. Then, an excess of ammonia water was added to the solution and stirred vigorously until the pH value was 10. The resulting solution was stirred for another 3 hours and then allowed to stand for 24 hours. The precipitate was then filtered and washed 3 times with ultrapure water; the filter cake was dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO2-CeO2-MgO carrier, which was naturally cooled and crushed through a 20-40 mesh sieve for later use; e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, and 1 / 2 of the mass of the mixed solution is added to the TiO2-CeO2-MgO carrier. Stir and impregnate at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0019] Preparation Example 3 A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst, with TiO2-CeO2-MgO as the carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 80 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius to allow the o-chlorotoluene to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 5 parts of the NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst at a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0020] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0021] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol Sb2O3, add 500 mL of concentrated hydrochloric acid (mass fraction 37%), heat under reflux until completely dissolved to form SbCl3 solution, cool and dilute to 1000 mL with deionized water for later use; d. A TiO2-CeO2-MgO carrier with a Ti:Ce:Mg molar ratio of 9:0.5:0.2 was prepared by co-precipitation. First, the required amount of TiCl4, Ce(NO3)3·6H2O and Mg(NO3)2·6H2O were dissolved in ultrapure water to form a solution at room temperature. Then, an excess of ammonia water was added to the solution and stirred vigorously until the pH value was 10. The resulting solution was stirred for another 3 hours and then allowed to stand for 24 hours. The precipitate was then filtered and washed 3 times with ultrapure water; the filter cake was dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO2-CeO2-MgO carrier, which was naturally cooled and crushed through a 20-40 mesh sieve for later use; e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, and 1 / 2 of the mass of the mixed solution is added to the TiO2-CeO2-MgO carrier. Stir and impregnate at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0022] Comparative Preparation Example 1 The same method as Preparation Example 1 was used, but NiMo / Al2O3 was used as the catalyst to prepare o-chlorobenzonitrile.

[0023] The following steps are involved: Step 1: Prepare NiMo / Al2O3 catalyst with Al2O3 as carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 60 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius to allow the o-chlorotoluene to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 8 parts of the NiMo / Al2O3 composite catalyst at a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0024] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0025] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Al2O3 is passed through a 20-40 mesh sieve for later use; d. Mixed impregnation: The solutions obtained in steps a and b are mixed in a volume ratio of 1:1, 1 / 2 of the mass of the mixed solution is added to the Al2O3 carrier, and the mixture is stirred and impregnated at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0026] Comparative Preparation Example 2 The same method as Preparation Example 1 was used, but NiMo / TiO2 was used as the catalyst to prepare o-chlorobenzonitrile.

[0027] A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo / TiO2 catalyst with TiO2 as carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 60 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius until the o-chlorotoluene began to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 8 parts of the above-mentioned NiMo / TiO2 catalyst in a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0028] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0029] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Dissolve TiCl₄ in ultrapure water to form a solution at room temperature. Next, add excess ammonia to the solution and stir vigorously until the pH reaches 10. Stir the resulting solution for an additional 3 hours and then allow it to stand for 24 hours. The precipitate is then filtered and washed three times with ultrapure water. The resulting filter cake is dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO₂ support. After cooling, pulverize through a 20-40 mesh sieve for later use. e. Mixed impregnation: The solutions obtained in steps a and b are mixed in a volume ratio of 1:1, 1 / 2 of the mass of the mixed solution is added to the TiO2 carrier, stirred and impregnated at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0030] Comparative Preparation Example 3 The same method as Preparation Example 1 was used, but NiMo-WO3 / TiO2 was used as the catalyst to prepare o-chlorobenzonitrile.

[0031] A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-WO3 / TiO2 composite catalyst, with TiO2 as the carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 60 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius until the o-chlorotoluene began to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 8 parts of the above-mentioned NiMo-WO3 / TiO2 composite catalyst in a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0032] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0033] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of tungsten solution: Weigh 0.1 mol of Na2WO4·2H2O and add 1000 mL of deionized water. Heat and dissolve. d. Dissolve TiCl₄ in ultrapure water to form a solution at room temperature. Next, add an excess of aqueous ammonia to the solution and stir vigorously until the pH reaches 10. Stir the resulting solution for an additional 3 hours and then allow it to stand for 24 hours. The precipitate is then filtered and washed three times with ultrapure water. The resulting filter cake is dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO₂ support. After cooling, pulverize the mixture through a 20-40 mesh sieve for later use. e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, 1 / 2 of the mass of the mixed solution is added to the TiO2 carrier, and the mixture is stirred and impregnated at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0034] Preparation Example 4 The same method as Preparation Example 1 was used, but NiMo-Sb2O3 / TiO2 was used as the catalyst to prepare o-chlorobenzonitrile.

[0035] A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-Sb2O3 / TiO2 composite catalyst, the carrier is TiO2-CeO2-MgO; Step 2: o-chlorobenzonitrile synthesis reaction: 60 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius to allow the o-chlorotoluene to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 8 parts of the NiMo-Sb2O3 / TiO2 composite catalyst at a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0036] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0037] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol Sb2O3, add 500 mL of concentrated hydrochloric acid (mass fraction 37%), heat under reflux until completely dissolved to form SbCl3 solution, cool and dilute to 1000 mL with deionized water for later use; d. Dissolve TiCl₄ in ultrapure water to form a solution at room temperature. Next, add an excess of aqueous ammonia to the solution and stir vigorously until the pH reaches 10. Stir the resulting solution for an additional 3 hours and then allow it to stand for 24 hours. The precipitate is then filtered and washed three times with ultrapure water. The resulting filter cake is dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO₂ support. After cooling, pulverize the mixture through a 20-40 mesh sieve for later use. e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, 1 / 2 of the mass of the mixed solution is added to the TiO2 carrier, and the mixture is stirred and impregnated at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0038] Preparation Example 5 The same method as Preparation Example 1 was used, but NiMo-Sb2O3 / TiO2-CeO2 was used as the catalyst to prepare o-chlorobenzonitrile.

[0039] A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-Sb2O3 / TiO2-CeO2 composite catalyst, with TiO2-CeO2 as the carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 60 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius until the o-chlorotoluene began to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 8 parts of the above-mentioned NiMo-Sb2O3 / TiO2-CeO2 composite catalyst in a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0040] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0041] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol Sb2O3, add 500 mL of concentrated hydrochloric acid (37% by mass), heat under reflux until completely dissolved to form a SbCl3 solution, cool and dilute to 1000 mL with deionized water for later use; d. A TiO2-CeO2 carrier with a Ti:Ce molar ratio of 9:0.3 was prepared by coprecipitation. First, the required amounts of TiCl4 and Ce(NO3)3·6H2O were dissolved in ultrapure water to form a solution at room temperature. Next, an excess of ammonia was added to the solution and stirred vigorously until the pH reached 10. The resulting solution was stirred for another 3 hours and then allowed to stand for 24 hours. The precipitate was then filtered and washed three times with ultrapure water. The resulting filter cake was dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO2-CeO2 carrier. After natural cooling, it was crushed through a 20-40 mesh sieve for later use. e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, and 1 / 2 of the mass of the mixed solution is added to a TiO2-CeO2 carrier. Stir and impregnate at room temperature for 2 hours to allow the active component to be evenly distributed and adsorbed on the surface of the carrier. Finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0042] Preparation Example 6 The same method as Preparation Example 1 was used, but NiMo-Sb2O3 / TiO2-CeO2-CuO was used as the catalyst to prepare o-chlorobenzonitrile.

[0043] A synthesis process for o-chlorobenzonitrile, characterized in that it comprises the following steps: Step 1: Prepare NiMo-Sb2O3 / TiO2-CeO2-CuO composite catalyst, with TiO2-CeO2-CuO as the carrier; Step 2: o-chlorobenzonitrile synthesis reaction: 60 parts of o-chlorotoluene were placed in a reactor and the temperature was adjusted to 210 degrees Celsius to allow the o-chlorotoluene to vaporize. The vaporized o-chlorotoluene, ammonia, and air were introduced into a fluidized bed reactor containing 8 parts of the NiMo-Sb2O3 / TiO2-CeO2-CuO composite catalyst at a volume ratio of 4:1:1. The o-chlorobenzonitrile synthesis was carried out at a reaction temperature of 430°C and a reaction pressure of 0.12 MPa for 4 hours.

[0044] Step 3: Product separation and purification: The reaction product is first condensed and cooled to room temperature to obtain a gas-liquid mixture; the gas-liquid mixture is subjected to gas-liquid separation to obtain a liquid crude product and unreacted gas; the unreacted gas can be recycled after recovery treatment; the liquid crude product is washed twice with a 3% by mass sodium hydroxide solution and once with deionized water; the filtered filtrate is subjected to vacuum distillation, and the fraction with a vacuum degree of 0.09 MPa and a temperature of 120°C is collected to obtain the o-chlorobenzonitrile product.

[0045] Wherein, the specific preparation process of the catalyst in step 1 is: a. Nickel solution preparation: nickel nitrate is dissolved in deionized water to form a saturated solution; b. Molybdenum solution preparation: ammonium molybdate is dissolved in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol of Sb2O3, add 500 mL of concentrated hydrochloric acid (37% by mass), heat under reflux until completely dissolved to form a SbCl3 solution, cool and dilute to 1000 mL with deionized water for later use; d. A TiO2-CeO2-CuO support with a Ti:Ce:Cu molar ratio of 9:0.3:0.2 was prepared by coprecipitation. First, the required amount of TiCl4, Ce(NO3)3·6H2O, and CuSO4·5H2O were dissolved in ultrapure water to form a solution at room temperature. Then, an excess of ammonia water was added to the solution and stirred vigorously until the pH value was 10. The resulting solution was stirred for another 3 hours and then allowed to stand for 24 hours. The precipitate was then filtered and washed three times with ultrapure water. The filter cake was dried at 110°C overnight and finally calcined at 450°C for 5 hours to obtain the TiO2-CeO2-CuO support. After natural cooling, it was crushed and passed through a 20-40 mesh sieve for later use. e. Mixed impregnation: The solutions obtained in steps a, b, and c are mixed in a volume ratio of 1:1:0.5, and 1 / 2 of the mass of the mixed solution is added to the TiO2-CeO2-CuO carrier. Stir and impregnate at room temperature for 2 hours to allow the active components to be evenly distributed and adsorbed on the carrier surface; finally, the impregnated carrier is transferred to an oven, dried at 110°C overnight, and then calcined at 450°C for 5 hours. After natural cooling, it is crushed through a 20-40 mesh sieve for later use.

[0046] Test Example 1 To determine the conversion of o-chlorotoluene in Preparation Examples 1-3 and Comparative Preparation Examples 1-6, 1 mL of the condensed crude liquid product was sampled from the gas-liquid mixture at the reactor outlet. 0.5 mL of n-dodecane (an internal standard with a known concentration) was added and diluted to 10 mL with ethyl acetate. The mixture was shaken evenly and allowed to stand for stratification. The supernatant was filtered through a 0.22 μm organic filter and analyzed by gas chromatography using a DB-5 column. To ensure complete separation of o-chlorotoluene, o-chlorobenzonitrile, and byproducts, the gas chromatography conditions were an initial temperature of 80°C for 2 minutes, followed by a temperature increase of 10°C / min to 200°C and a holding time of 5 minutes. Nitrogen (purity ≥99.999%) was used at a flow rate of 1.0 mL / min and a split ratio of 20:1. n-dodecane was used as the internal standard. The o-chlorotoluene content was calculated by comparing the peak areas of o-chlorotoluene and the internal standard. The o-chlorotoluene conversion (X) was calculated using the following formula: Each test case was repeated three times, and the results are as follows: Table 1 Determination of conversion rate of o-chlorotoluene ; The results showed that the conversion rates of o-chlorotoluene prepared by the methods of Preparation Examples 1-3 and Comparative Preparation Examples 3-6 were all high, and the conversion rate of o-chlorotoluene prepared by Preparation Examples 1-3 was the highest, both greater than 90%.

[0047] Test Example 2 Preparation Example 1-3 and Comparative Preparation Example 1-6 Detection of the selectivity of o-chlorotoluene: 2 mL of the condensed crude liquid product was sampled from the gas-liquid mixture at the outlet of the reactor, 0.5 g of anhydrous sodium sulfate was added, and the mixture was shaken for 1 minute to remove moisture. Then, 1 mL of a 0.1 mg / mL 2,4-dichlorotoluene solution was added as an internal standard, and the mixture was shaken for 5 minutes. 3 mL of acetonitrile was added to the above mixture, and ultrasonic extraction was performed for 15 minutes (power 300 W, temperature 30°C), followed by centrifugation at 8000 r / min for 10 minutes, and the upper organic phase was collected. The extraction process was repeated once, and the two upper organic phases were combined and diluted to 10 mL with acetonitrile. The filtrate was filtered through a 0.22 μm organic phase filter, and the filtrate was subjected to gas chromatography-mass spectrometry. Standard solutions of o-chlorobenzonitrile, o-chlorobenzaldehyde, and benzonitrile were prepared simultaneously, and standard curves were plotted, using 2,4-dichlorotoluene as the internal standard. Chromatographic detection conditions were an initial temperature of 80°C for 2 minutes, followed by a temperature increase of 10°C / min to 200°C for 5 minutes. Ions (m / z) were selected based on the characteristic mass spectrometric characteristics of the target compound and the internal standard. Samples were injected and analyzed according to the above GC-MS conditions. The concentrations of o-chlorobenzonitrile (C1), o-chlorobenzaldehyde (C2), and benzonitrile (C3) in the sample were determined based on the standard curve. The mass of each substance was calculated based on the volume of the diluted solution, and then converted to molar amounts (n1, n2, and n3) based on the molar mass of each substance. The o-chlorobenzonitrile selectivity (S) was calculated according to the following formula: Each test case was repeated three times, and the results are as follows: Table 2 Selective determination of o-chlorotoluene ; The results showed that the o-chlorotoluene prepared by the methods of Preparation Examples 1-3 and Comparative Preparation Examples 4-6 had high selectivity, and the o-chlorotoluene prepared by Preparation Example 1-3 had the highest selectivity, greater than 95%.

[0048] Test Example 3 Determination of carbon deposits in Preparation Examples 1-3 and Comparative Preparation Examples 1-6: The mass change of the catalyst obtained during the programmed temperature increase process was quickly measured using the muffle furnace calcination method, and the carbon deposit amount of the catalyst was calculated after 150 hours of continuous reaction. After washing and drying the catalyst, the mass (m1) was weighed and placed in a porcelain crucible with a constant weight. The crucible was placed in a muffle furnace and heated to 700°C at a rate of 5°C / min in an air atmosphere for 3 hours (to ensure complete combustion of the carbon deposits). After cooling to room temperature, the mass of the residual catalyst was weighed (m2). The carbon deposit amount (%) was calculated according to the following formula = (m1- m2) / m1× 100%; each test example was repeated three times, and the results are as follows: Table 3 Determination of carbon deposit amount of o-chlorotoluene ; The results show that the carbon deposits prepared by the methods of Preparation Examples 1-3 and Comparative Preparation Examples 5-6 are relatively low, and the carbon deposits prepared by Preparation Example 1-3 are the smallest, less than 3%.

[0049] Test Example 4 Stability of the active components of Preparation Examples 1-3 and Comparative Preparation Examples 1-6: The continuous reaction life of each group was tested, and the endpoint was set when the conversion rate of o-chlorotoluene dropped to 80% of the initial value. The cumulative running time was calculated; the results are shown below: Table 4 Stability determination of o-chlorotoluene

[0050] The results show that the o-chlorotoluene prepared by the methods of Preparation Examples 1-3 and Comparative Preparation Examples 5-6 has higher stability, and the o-chlorotoluene prepared by Preparation Example 1-3 has the highest stability, which is greater than 300 hours.

[0051] The results showed that the NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst had the highest catalytic efficiency. The o-chlorotoluene prepared using this method exhibited high conversion, good selectivity, minimal carbon deposition, and the highest active component stability. We hypothesize that while NiMo provides active sites for hydrogenation, Sb2O3 regulates NH3 adsorption and suppresses polychlorinated byproducts, increasing oxygen vacancies at the Sb-O-Ti interface, promoting reactant activation and inhibiting deep oxidation. TiO2, as a support, has a certain effect in promoting the oxidation of chloroaromatic hydrocarbons. The introduction of Ce improves the dispersion of the active component. When Ce and Mg are introduced simultaneously as alkaline additives, the dispersion of the active component is more effective than adding either element alone, effectively balancing the deactivation caused by carbon deposition due to acid-base imbalance.

[0052] It should be noted that the above description is only a preferred embodiment of the present invention. Any changes made according to the concept of the present invention, as long as the resulting functions and effects do not exceed the spirit covered by the description, should be within the scope of the present invention.

[0053] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0054] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A synthesis process for o-chlorobenzonitrile, characterized in that, The following steps are involved: Step 1: preparing a NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst, wherein the catalyst carrier is TiO2-CeO2-MgO; Step 2: o-chlorobenzonitrile synthesis reaction: 60-80 parts of o-chlorotoluene are placed in a reactor and the temperature is adjusted to 210° C. to vaporize the o-chlorotoluene; the vaporized o-chlorotoluene, ammonia and air are introduced into a fluidized bed reactor containing 5-8 parts of the NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst in a volume ratio of 4:1:1, and the reaction is carried out at a reaction temperature of 430° C. and a reaction pressure of 0.12 MPa for 4 hours; Step 3: Product separation and purification: The reaction product is condensed to room temperature to obtain a gas-liquid mixture. After gas-liquid separation, the liquid crude product is taken, washed with sodium hydroxide solution and deionized water in sequence, filtered, and the filtrate is subjected to vacuum distillation to obtain the o-chlorobenzonitrile product.

2. The synthesis process according to claim 1, wherein The preparation process of the NiMo-Sb2O3 / TiO2-CeO2-MgO composite catalyst in step 1 includes: a. Nickel solution preparation: dissolve nickel nitrate in deionized water to form a saturated solution; b. Molybdenum solution preparation: dissolve ammonium molybdate in deionized water to form a saturated solution; c. Preparation of antimony solution: Weigh 0.1 mol of Sb2O3 and add 500 mL of 37% concentrated hydrochloric acid. Heat under reflux until completely dissolved to form a SbCl3 solution. After cooling, dilute to 1000 mL with deionized water. d. Support preparation: A TiO2-CeO2-MgO support was prepared by coprecipitation, with a Ti:Ce:Mg molar ratio of 9:(0.3-0.5):(0.2-0.3). e. Mixed impregnation: The solutions of steps a, b, and c were mixed in a volume ratio of 1:1:0.5, and 1 / 2 of the mass of the mixture was added to the TiO2-CeO2-MgO carrier. The mixture was stirred and impregnated at room temperature for 2 hours, dried overnight at 110 ° C, calcined at 450 ° C for 5 hours, and crushed through a 20-40 mesh sieve.

3. The synthesis process according to claim 1, wherein The liquid crude product obtained in the product separation and purification in step 3 needs to be washed twice with a 3% by mass sodium hydroxide solution and then washed once with deionized water; the vacuum degree of the vacuum distillation is 0.09 MPa, and the fraction at 120° C. is collected to obtain the o-chlorobenzonitrile product.

4. The synthesis process according to any one of claims 1 to 3, characterized in that The specific preparation process of the TiO2-CeO2-MgO carrier is as follows: TiCl4, Ce (NO3)3・6H2O and Mg (NO3)2・6H2O are dissolved in ultrapure water, excess ammonia water is added at room temperature and stirred until the pH is 10, stirring is continued for 3 hours and then allowed to stand for 24 hours. The precipitate is filtered, washed with ultrapure water three times, dried at 110℃ overnight, calcined at 450℃ for 5 hours, and crushed through a 20-40 mesh sieve.

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