Preparation process of 2-bromoheptafluoropropane

Abstract

The invention discloses a preparation process of 2-bromoheptafluoropropane, which takes heptafluoropropane as a raw material to carry out bromination reaction, specifically, hydrogen on a No.2 carbon atom is substituted by bromine to generate 2-bromoheptafluoropropane, and hydrogen bromide is generated at the same time. And hydrogen bromide is absorbed by water and then is treated by liquid caustic soda to generate sodium bromide.

Description

Technical Field

[0001] The present invention relates to a preparation process of 2-bromoheptafluoropropane, belonging to the chemical engineering field. Background Art

[0002] In the mid-20th century, American scientists extracted the plant alkaloid ryanodine from the South American Flacourtiaceae shrub Ryania speciosa, which can be used as a natural insecticide and has a history of more than 50 years. This plant is highly poisonous to humans and animals. Local Indians often mashed it and applied it to arrowheads to make poisoned arrows. After being shot, animals showed convulsions and tension in their whole body muscles and finally died like zombies. Its extract is very effective against Lepidoptera pests, including European corn borer, sugarcane borer, apple leaf roller, apple fruit borer, gypsy moth, etc. However, due to the high toxicity of ryanodine to humans and animals, causing rigid paralysis in mammals, its popularization and application have been restricted. Previous studies on ryanodine mainly focused on structural modification, hoping to discover compounds with selective toxicity. Although there are many literature reports, no highly active and safe products have been obtained through structural modification so far.

[0003] In 1989, Dr. Tsuda in Japan reported a chemically synthesized compound acting on the ryanodine receptor in his doctoral thesis, which has bactericidal and herbicidal activities but no insecticidal activity. The Japanese pesticide company carried out a large amount of R & D work on this compound, and during this period, Bayer also participated. Finally, in 1998, the first ryanodine receptor modulator insecticide - flubendiamide was reported. In order to bypass the patents of the Japanese pesticide company and Bayer, DuPont made significant modifications to the active structure and groups, and finally launched chlorantraniliprole in 2000. These two compounds have excellent control effects on almost all Lepidoptera pests, but are ineffective against pests of other orders. Flubendiamide was first launched in Japan in 2007 (registered on various vegetables and fruit trees), and successively obtained registrations in India (registered on rice and cotton), South Korea (vegetables, fruit trees and rice), and China in 2008, and gradually began to be on the market: Chlorantraniliprole was launched in the Philippines in 2007 (rice), and then promoted and sold globally. Its market launch schedule, registered crops, and publicity efforts are better than those of flubendiamide. DuPont's cyantraniliprole was launched in 2012. This is the second-generation ryanodine receptor inhibitor insecticide successfully developed by DuPont after chlorantraniliprole. Cyantraniliprole is formed by changing various polar groups on the benzene ring, is more efficient, has a wider range of applicable crops, and can effectively control Lepidoptera, Hemiptera and Coleoptera pests. Currently, many companies are still researching compounds of this type, and some varieties have made breakthroughs in the insecticidal spectrum. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to provide a preparation process of 2-bromoheptafluoropropane.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is:

[0006] A preparation process of 2-bromoheptafluoropropane, comprising the following steps:

[0007] Using heptafluoropropane as a raw material to carry out bromination reaction, specifically, the hydrogen on the 2nd carbon atom is replaced by bromine to generate 2-bromoheptafluoropropane, and hydrogen bromide is generated at the same time. The hydrogen bromide is absorbed by water and then treated with liquid alkali to generate sodium bromide.

[0008] Further, it specifically comprises the following steps:

[0009] ① Raw material preparation

[0010] Heat up the preheating kettle by jacket steam and control the temperature at 60 - 70 °C; after measuring 685 kg of bromine by the bromine metering tank, put it into the preheating kettle, and at the same time, after buffering 700 kg of heptafluoropropane through the heptafluoropropane buffer tank, put it into the preheating kettle;

[0011] ② Bromination reaction

[0012] After the above raw materials are preheated, they enter the quartz heating reaction furnace preheated to 400 °C by electric heating in gaseous form to carry out bromination reaction;

[0013] ③ Cooling and separation

[0014] After the reaction is completed, the material passes through the pipeline through the cooling water tank and is cooled to about 60 °C, and enters the gas-liquid separator in gaseous form; the material is further cooled to room temperature through the gas-liquid separator and the condensation separator (first using chilled brine); the unreacted bromine and a small amount of water carried in the material are condensed into a liquid phase and enter the bromine water separator, and the gaseous material enters the water washing tower for subsequent treatment; the liquid phase material is cooled by a glass cooler (using circulating water) in the bromine water separator and then stratified. The bromine-rich material at the bottom is recycled at this position, and the upper layer is the bromine-containing mother liquor, which enters the concentration kettle and is sent to the by-product workshop;

[0015] ④ Water washing

[0016] The gaseous material enters the water washing tower for water spray washing, and the hydrogen bromide and the unreacted bromine carried out are washed down to become bromine water, which enters the bromine water separator, is cooled by a glass cooler and then stratified. The bromine-rich material at the bottom is recycled at this position, and the upper layer is the bromine-containing waste water, which enters the neutralization kettle and is sent to the by-product workshop; the gaseous material enters the alkali washing tower;

[0017] ⑤ Alkali washing

[0018] The gaseous material after water washing mainly consists of crude 2-bromoheptafluoropropane and a small amount of hydrogen bromide gas entrained. The acidic substances are neutralized by spraying with liquid alkali, and the resulting alkaline washing wastewater enters the neutralization kettle;

[0019] ⑥ Dehydration and drying

[0020] The gaseous material enters the gas holder through a buffer. The gas holder uses a water seal and discharges pressure through a vent pipe when the pressure is too high;

[0021] The crude product in the gas holder first enters a freezing dehydrator (freezing brine at -10°C) for dehydration, and then passes through a molecular sieve dryer to further remove moisture;

[0022] ⑦ Degassing

[0023] The dried gaseous material is pumped into a deep condenser by a compressor, condensed using freezing brine and then enters the crude product intermediate tank. Then, the gas-liquid material is pressed into a degassing tower, heated by jacket steam with the temperature controlled below 60°C, the top of the tower is cooled with freezing brine, the top temperature is controlled at -10°C, and the pressure of the degassing tower is maintained at 2.0 MPa. After the material refluxes in the system for two hours, the non-condensable gas phase removed from the top of the tower is heptafluoropropane, which returns to the preheating kettle as raw material for further reaction; the liquid material at the bottom of the tower enters the rectification tower;

[0024] ⑧ Rectification

[0025] The rectification tower is heated by jacket steam, the temperature at the bottom of the kettle is controlled below 50°C, the top of the tower is cooled with freezing brine, the top temperature is controlled around 0°C, the pressure of the rectification tower is maintained at 1.0 MPa, and the material is collected after refluxing for two hours;

[0026] ⑨ Drying and filling

[0027] The material after rectification is dried by a molecular sieve dryer and then pumped into the finished product tank, and the product is filled, about 990 kg, which is intermediate 1 - 2-bromoheptafluoropropane.

[0028] Advantages of the present invention:

[0029] The preparation process of 2-bromoheptafluoropropane provided by the present invention has a high product yield, is economical and environmentally friendly, and is suitable for large-scale industrial applications. Detailed implementation mode

[0030] Example 1

[0031] This example provides a preparation process of 2-bromoheptafluoropropane, including the following steps:

[0032] ① Raw material preparation

[0033] Heat up the preheating kettle by jacket steam and control the temperature at 60 - 70°C; after measuring 685 kg of bromine with a bromine metering tank, put it into the preheating kettle. At the same time, buffer 700 kg of heptafluoropropane through a heptafluoropropane buffer tank and then put it into the preheating kettle.

[0034] ② Bromination reaction

[0035] After the above raw materials are preheated, they enter a quartz heating reactor preheated to 400°C by electric heating in gaseous form for bromination reaction.

[0036] ③ Cooling and separation

[0037] After the reaction is completed, the material passes through a pipeline through a cooling water tank and is cooled to about 60°C, and then enters a gas-liquid separator in gaseous form; the material is further cooled to room temperature through a gas-liquid separator and a condensation separator (first using chilled brine); the unreacted bromine and a small amount of water carried in the material are condensed into a liquid phase and enter a bromine water separator, and the gaseous material enters a water washing tower for subsequent treatment; the liquid phase material is cooled by a glass cooler (using circulating water) in the bromine water separator and then stratified. The bromine-rich material at the bottom is recycled at this station, and the upper layer is bromine-containing mother liquor, which enters a concentration kettle and is sent to the by-product workshop.

[0038] ④ Water washing

[0039] The gaseous material enters a water washing tower for water spray washing to wash down the hydrogen bromide and the unreacted bromine carried out to form bromine water, which enters a bromine water separator, is cooled by a glass cooler and then stratified. The bromine-rich material at the bottom is recycled at this station, and the upper layer is bromine-containing wastewater, which enters a neutralization kettle and is sent to the by-product workshop; the gaseous material enters an alkali washing tower.

[0040] ⑤ Alkali washing

[0041] The gaseous material after water washing is mainly crude 2-bromoheptafluoropropane and a small amount of hydrogen bromide gas carried out. Spray and neutralize the acidic substances with liquid alkali, and the alkali washing wastewater is generated and enters the neutralization kettle.

[0042] ⑥ Dehydration and drying

[0043] The gaseous material enters a gas holder through a buffer. The gas holder uses a water seal and discharges pressure through a vent pipe when the pressure is too high.

[0044] The crude product in the gas holder first enters a freezing dehydrator (chilled brine at -10°C) for dehydration, and then is further dehydrated by a molecular sieve dryer.

[0045] ⑦ Degassing

[0046] The dried gaseous material is pumped into a deep condenser by a compressor, condensed by chilled brine and then enters the intermediate tank for crude products. Then, the gas-liquid material is pressed into a degassing tower, heated by jacket steam with the temperature controlled below 60°C. The top of the tower is cooled by chilled brine, with the top temperature controlled at -10°C, and the pressure of the degassing tower is maintained at 2.0 MPa. After the material refluxes in the system for two hours, the non-condensable gas phase discharged from the top of the tower, which is heptafluoropropane, returns to the preheating kettle as raw material for further reaction; the liquid material at the bottom of the tower enters the rectifying tower.

[0047] ⑧ Rectification

[0048] The rectifying tower is heated by jacket steam, with the temperature at the bottom of the kettle controlled below 50°C. The top of the tower is cooled by chilled brine, with the top temperature controlled at about 0°C, and the pressure of the rectifying tower is maintained at 1.0 MPa. After refluxing for two hours, the material is collected.

[0049] ⑨ Drying and filling

[0050] The material after rectification is dried by a molecular sieve dryer and then pumped into the finished product tank, and the product is obtained for filling, about 990 kg, which is intermediate 1, 2-bromoheptafluoropropane.

[0051] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A process for preparing 2-bromoheptafluoropropane, characterized in that: The following steps are involved: Bromination reaction takes place with heptafluoropropane as raw material, specifically, the hydrogen on carbon atom No. 2 is replaced by bromine to generate 2-bromoheptafluoropropane and hydrogen bromide at the same time; the hydrogen bromide is absorbed by water and then treated with liquid alkali to generate sodium bromide.

2. A process for preparing 2-bromoheptafluoropropane according to claim 1, characterized in that: The following steps are involved: Process: Raw material preparation: the preheating kettle is heated by jacket steam and the temperature is controlled at 60-70℃; 685kg of bromine is measured by the bromine metering tank and then put into the preheating kettle; at the same time, 700kg of heptafluoropropane is buffered by the heptafluoropropane buffer tank and then put into the preheating kettle; Bromination reaction: After being preheated, the above raw materials enter the quartz heating reaction furnace preheated to 400°C by electric heating in the form of gas phase to undergo bromination reaction; After the reaction is completed, the material is cooled to about 60°C through a cooling water tank through a pipeline and enters a gas-liquid separator in the form of gas phase; the material is further cooled to room temperature through a gas-liquid separator and a condensation separator (using frozen brine first); the unreacted bromine and a small amount of water brought into the material are condensed into a liquid phase and enter the bromine water separator, and the gas phase material enters a water washing tower for subsequent treatment; the liquid phase material is cooled in a glass cooler (using circulating water) in the bromine water separator and then stratified, the bromine-rich material at the bottom layer is recovered at this post, and the upper layer is a bromine-containing mother liquor, which enters a concentration kettle and is sent to a by-product workshop; Water washing: The gaseous material enters the water washing tower for water spray washing, and the hydrogen bromide and the unreacted bromine are washed out to become bromine water, which enters the bromine water separator, is cooled in the glass cooler and then separated into layers. The bromine-rich material at the bottom is recycled at this post, and the upper layer is bromine-containing wastewater, which enters the neutralization kettle and is sent to the by-product workshop; the gaseous material enters the alkali washing tower; Alkali washing and water washing are mainly crude 2-bromoheptafluoropropane and a small amount of hydrogen bromide gas entrained. Liquid alkali is used to spray and neutralize the acidic substances therein, and the alkaline washing wastewater is generated and enters the neutralization kettle; Dehydration and drying: gaseous materials enter the gas cabinet through the buffer. The gas cabinet adopts water seal. When the pressure is too high, the pressure is released through the vent pipe. The crude product in the gas cabinet first enters the freezer dehydrator (frozen brine -10°C) for dehydration, and then passes through the molecular sieve dryer to further remove moisture; The gaseous materials after degassing and drying are pumped into the deep condenser through the compressor, condensed by frozen brine and then enter the crude product intermediate tank, and then the gaseous and liquid materials are pressed into the degassing tower, heated by jacket steam, and the temperature is controlled below 60℃. The top of the tower is cooled by frozen brine, and the top temperature is controlled at -10℃, and the pressure of the degassing tower is maintained at 2.0MPa. After the material refluxes in the system for two hours, the non-condensable gas phase released from the top of the tower is heptafluoropropane, which returns to the preheating kettle as raw material for further reaction; the liquid material in the kettle enters the distillation tower; Distillation: The distillation tower is heated by jacket steam, the kettle temperature is controlled below 50°C, the top of the tower is cooled by refrigerated brine, the top temperature is controlled at about 0°C, the pressure of the distillation tower is maintained at 1.0MPa, and the material is collected after two hours of reflux; Drying and filling: After distillation, the material is dried in a molecular sieve dryer and then pumped into a finished product tank to obtain a product for filling, about 990 kg, which is the intermediate 2-bromoheptafluoropropane.