Preparation process of benzoyl chloride

Abstract

The invention discloses a preparation process of benzoyl chloride. The preparation process comprises the following steps of synthesis of benzotrichloride: carrying out temperature reaction on methylbenzene and chlorine under the catalytic action of a catalyst to synthetize a crude benzotrichloride product; synthesis of the benzoyl chloride: continuously stirring and heating the crude benzotrichloride product and benzoic acid to prepare a crude benzoyl chloride product after adding the catalyst; refining of the benzoyl chloride: carrying out reduced pressure distillation on the crude benzoyl chloride product to prepare a refined benzoyl chloride product; recovering benzoyl chloride raffinate, adding water to the benzoyl chloride raffinate which is subjected to the reduced pressure distillation, heating and stirring to transform the benzoyl chloride contained in the raffinate into the benzoic acid, cooling, then separating out benzoic acid. The preparation process disclosed by the invention is easy to safe to operate, effectively shortens the reaction time, achieves the purity of the prepared benzoyl chloride by 99.5%, reduces the environmental pollution by recycling residues, saves the resources, reduces the cost, meets the requirements of pharmaceutical chemicals and can carry out massive industrial production.

Description

technical field

[0001] The invention relates to the preparation and purification of benzoyl chloride and belongs to the field of organic compound synthesis. Background technique

[0002] Benzoyl chloride is widely used in the production of monomers in pesticides, medicines and dyes. At present, the preparation of benzoyl chloride mainly uses trichlorotoluene as a raw material, and the production cost is high.

[0003] At present, in the process of producing benzoyl chloride, a black viscous residue is produced in the distillation kettle at the later stage of distillation, which contains benzoic acid, benzoyl chloride, benzoic anhydride, catalyst and tar, wherein benzoic acid and benzoic acid are organic matter , because they are mixed in the residue and cannot be completely evaporated, they are generally discharged together with the residue or incinerated, resulting in waste of resources, high cost, and environmental pollution.

[0004] The side chain chlorination of toluen...

Examples

Embodiment 1

[0028] Put 1300 kg of toluene into the chlorination reaction kettle, open the steam valve of the jacket of the reaction kettle, raise the temperature of the material in the reaction kettle to 80°C, weigh 4 kg of azobisisobutyronitrile and dissolve it with 25 kg of trichlorotoluene, slowly drop into the reaction kettle, and open the valve of the chlorine gas pipeline. The chlorine gas passes through the flow meter from the bottom of the chlorination reaction kettle through the distributor and contacts with toluene to generate a side chain chlorination reaction. Adjust the jacket steam or cooling water valve of the chlorination kettle to maintain the reaction temperature. At 80-130°C, monochlorotoluene starts to be generated, continue to pass chlorine to obtain dichlorotoluene, and finally generate trichlorotoluene. When the content of dichlorotoluene in the chlorinated material is less than 0.2%, stop the chlorine flow and use compressed air Remove a small amount of chlorination...

Embodiment 2

[0031] Put 1400 kg of toluene into the chlorination reaction kettle, open the jacket steam valve of the reaction kettle, raise the temperature of the material in the reaction kettle to 90°C, weigh 3 kg of dibenzoyl peroxide and dissolve it with 30 kg of trichlorotoluene, slowly drop into the reaction kettle, and open the valve of the chlorine gas pipeline. The chlorine gas passes through the flow meter from the bottom of the chlorination reaction kettle through the distributor and contacts with toluene to generate a side chain chlorination reaction. Adjust the jacket steam or cooling water valve of the chlorination kettle to maintain the reaction temperature. At 90-130°C, monochlorotoluene starts to be generated, continue to pass chlorine to obtain dichlorotoluene, and finally generate trichlorotoluene. When the content of dichlorotoluene in the chlorinated material is less than 0.2%, stop the chlorine flow and use compressed air Remove a small amount of chlorination and residu...

Embodiment 3

[0034]Put 1000 kilograms of benzoic acid into the reaction kettle, then drop 0.585 kilograms of zinc chloride, then pump 1680 kilograms of trichlorotoluene dechlorination crude products into the kettle, open the vacuum system on the hydrochloric acid absorption device, and heat up under stirring to make the temperature Maintained at 60°C, and the vacuum degree is 740-750mmHg, depending on the amount of hydrogen chloride produced, the liquid in the kettle is black, and the temperature is raised to 120°C for 4 hours, and the hydrogen chloride gas to be generated is discharged from the reaction kettle, and the crude product of benzoyl chloride is obtained; The benzoyl chloride crude product of the zinc chloride catalyst is placed in a rectification kettle, heated to 165°C under reduced pressure, and the top pressure of the rectification tower is controlled to be 20mmHg, the top temperature of the rectification tower is 110°C, and the reflux ratio is 2 : 1, carry out rectification,...

technical field

[0001] The invention relates to the preparation and purification of benzoyl chloride and belongs to the field of organic compound synthesis. Background technique

[0002] Benzoyl chloride is widely used in the production of monomers in pesticides, medicines and dyes. At present, the preparation of benzoyl chloride mainly uses trichlorotoluene as a raw material, and the production cost is high.

[0003] At present, in the process of producing benzoyl chloride, a black viscous residue is produced in the distillation kettle at the later stage of distillation, which contains benzoic acid, benzoyl chloride, benzoic anhydride, catalyst and tar, wherein benzoic acid and benzoic acid are organic matter , because they are mixed in the residue and cannot be completely evaporated, they are generally discharged together with the residue or incinerated, resulting in waste of resources, high cost, and environmental pollution.

[0004] The side chain chlorination of toluen...

Examples

Embodiment 1

[0028] Put 1300 kg of toluene into the chlorination reaction kettle, open the steam valve of the jacket of the reaction kettle, raise the temperature of the material in the reaction kettle to 80°C, weigh 4 kg of azobisisobutyronitrile and dissolve it with 25 kg of trichlorotoluene, slowly drop into the reaction kettle, and open the valve of the chlorine gas pipeline. The chlorine gas passes through the flow meter from the bottom of the chlorination reaction kettle through the distributor and contacts with toluene to generate a side chain chlorination reaction. Adjust the jacket steam or cooling water valve of the chlorination kettle to maintain the reaction temperature. At 80-130°C, monochlorotoluene starts to be generated, continue to pass chlorine to obtain dichlorotoluene, and finally generate trichlorotoluene. When the content of dichlorotoluene in the chlorinated material is less than 0.2%, stop the chlorine flow and use compressed air Remove a small amount of chlorination...

Embodiment 2

[0031] Put 1400 kg of toluene into the chlorination reaction kettle, open the jacket steam valve of the reaction kettle, raise the temperature of the material in the reaction kettle to 90°C, weigh 3 kg of dibenzoyl peroxide and dissolve it with 30 kg of trichlorotoluene, slowly drop into the reaction kettle, and open the valve of the chlorine gas pipeline. The chlorine gas passes through the flow meter from the bottom of the chlorination reaction kettle through the distributor and contacts with toluene to generate a side chain chlorination reaction. Adjust the jacket steam or cooling water valve of the chlorination kettle to maintain the reaction temperature. At 90-130°C, monochlorotoluene starts to be generated, continue to pass chlorine to obtain dichlorotoluene, and finally generate trichlorotoluene. When the content of dichlorotoluene in the chlorinated material is less than 0.2%, stop the chlorine flow and use compressed air Remove a small amount of chlorination and residu...

Embodiment 3

[0034]Put 1000 kilograms of benzoic acid into the reaction kettle, then drop 0.585 kilograms of zinc chloride, then pump 1680 kilograms of trichlorotoluene dechlorination crude products into the kettle, open the vacuum system on the hydrochloric acid absorption device, and heat up under stirring to make the temperature Maintained at 60°C, and the vacuum degree is 740-750mmHg, depending on the amount of hydrogen chloride produced, the liquid in the kettle is black, and the temperature is raised to 120°C for 4 hours, and the hydrogen chloride gas to be generated is discharged from the reaction kettle, and the crude product of benzoyl chloride is obtained; The benzoyl chloride crude product of the zinc chloride catalyst is placed in a rectification kettle, heated to 165°C under reduced pressure, and the top pressure of the rectification tower is controlled to be 20mmHg, the top temperature of the rectification tower is 110°C, and the reflux ratio is 2 : 1, carry out rectification,...