Device and process for recovering triethylamine in production of 4.6-dichloro-5-fluoropyrimidine

Abstract

The invention relates to a device and process for recycling triethylamine in 4.6-dichloro-5-fluoropyrimidine production. The device comprises a reaction kettle, a filter press, a neutralization kettle, a distillation kettle and a receiving tank, and triethylamine acid salt solids output by a triethylamine tank are leached by dichloroethane in the reaction kettle; the discharging end of the reaction kettle is connected with the feeding end of the filter press, the solid material output end of the filter press is connected with the feeding end of the neutralization kettle, the feeding end of the neutralization kettle is further connected with the alkali liquor tank, and the discharging end of the neutralization kettle is connected with a water phase receiving tank and an organic phase receiving tank which are arranged in parallel. The output end of the organic receiving tank is connected with the input end of the distillation kettle; the input end of the receiving tank is connected with the upper end of the distillation kettle through a condenser, and gaseous triethylamine discharged from the distillation kettle enters the receiving tank after being cooled by the condenser. The method is reasonable in design, the production cost of 4.6-dichloro-5-fluoropyrimidine synthesis is effectively reduced, the amount of three wastes is reduced, the acid-binding agent triethylamine is recycled and reused, and meanwhile, the production environment for treating the catalyst in the production process is improved.

Description

Technical Field

[0001] This invention relates to a device and process for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine. Background Technology

[0002] 4,6-Dichloro-5-fluoropyrimidine (CAS: 213265-83-97) is a halopyrimidine organic compound with the molecular formula C4HCl2FN2 and a molecular weight of 166.97. It is a colorless or pale yellow liquid.

[0003] Triethylamine hydrochloride is an organic compound with the chemical formula C6H16ClN, a molecular weight of 137.65, and CAS number 554-68-7. It is a white or off-white powder with hygroscopic properties.

[0004] The mainstream synthetic route for 4,6-dichloro-5-fluoropyrimidine is as follows: starting from diethyl 2-fluoromalonate, it is prepared via cyclization / chlorination reactions. This is currently the most mature process, and the specific steps are as follows: Cyclolysis: 2-Fluorodiacidic acid diacetic acid was added to an acetamide-methanol-sodium methoxide solution and refluxed at 70-80 degrees Celsius for 6 hours. The mixture was then filtered, acidified, centrifuged, and dried to obtain intermediate 1. Chlorination: Intermediate 1 and phosphorus oxychloride are added to a reactor. Under the catalysis of triethylamine, the catalyst is added dropwise at a temperature below 20 degrees Celsius. The temperature is raised to 80-90 degrees Celsius and the reaction is carried out for 8 hours. The product is then obtained by ice melting, water washing, solvent removal and distillation, with a yield of about 72%.

[0005] The main drawbacks of this technology are: (1) large volume of "three wastes" (wastewater, waste gas, and solid waste), high phosphorus and nitrogen content in the wastewater, and high acidity; (2) difficulty in stratification after chlorination and quenching with water, resulting in a large amount of emulsion layer; (3) large amount of alkali required for neutralization; and (4) difficulty in recovering triethylamine. If the catalyst used to synthesize 4,6-dichloro-5-fluoropyrimidine is not recycled, it will have the above disadvantages in use. Summary of the Invention

[0006] The present invention addresses the problems existing in the prior art, namely, the technical problem to be solved by the present invention is to provide a device and process for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a device for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine, comprising a reaction vessel, a filter press, a neutralization vessel, a distillation vessel, and a receiving tank. The feed end of the reaction vessel is connected to a triethylamine tank and a dichloroethane tank. The triethylamine acid salt solid salt output from the triethylamine tank is washed with dichloroethane in the reaction vessel. The discharge end of the reaction vessel is connected to the feed end of the filter press. The solid material output end of the filter press is connected to the feed end of the neutralization vessel. The feed end of the neutralization vessel is also connected to an alkali tank. The discharge end of the neutralization vessel is connected to an aqueous phase receiving tank and an organic phase receiving tank arranged in parallel. The output end of the organic phase receiving tank is connected to the input end of the distillation vessel. The input end of the receiving tank is connected to the upper end of the distillation vessel through a condenser. The gaseous triethylamine discharged from the distillation vessel is cooled by the condenser and then enters the receiving tank.

[0008] Furthermore, the weight of dichloroethane in the reactor is 1.5-2 times that of the triethylamine salt solid.

[0009] Furthermore, the discharge end of the filter press is connected to the mother liquor receiving tank, and the output end of the mother liquor receiving tank is connected to the post-processing device through a mother liquor transfer pump.

[0010] Furthermore, the output end of the aqueous phase receiving tank is connected to an aqueous phase transfer pump, which transports the aqueous phase in the aqueous phase receiving tank to the sewage treatment plant.

[0011] Furthermore, the discharge end of the receiving tank is connected to the triethylamine testing tank, and the discharge end of the triethylamine testing tank is connected to a triethylamine delivery pump.

[0012] Furthermore, the reaction vessel, neutralization vessel, and distillation vessel are all equipped with stirrers.

[0013] Another technical solution adopted in this invention is: a process for producing triethylamine in 4,6-dichloro-5-fluoropyrimidine, comprising the following steps: (1) a triethylamine tank conveys triethylamine acid salt solid into a reaction vessel, and a dichloroethane tank conveys dichloroethane into the reaction vessel, thereby washing the triethylamine acid salt solid with dichloroethane; (2) the material output from the reaction vessel enters a filter press for solid-liquid separation, and the separated solid is sent into a neutralization vessel; (3) an alkali tank sends alkali solution into the neutralization vessel, and the solid is washed with dichloroethane; The body and the alkaline solution form a mixed liquid, which is then allowed to stand and separate into layers. The upper layer is organic matter; (4) The organic matter in the upper layer of the neutralization vessel is extracted and separated into an organic phase receiving tank, while the aqueous phase is sent into an aqueous phase receiving tank; (5) The organic matter in the organic phase receiving tank is sent to a distillation vessel for distillation; (6) The gaseous triethylamine discharged from the distillation vessel is condensed by a condenser and sent into a receiving tank; (7) The triethylamine in the receiving tank is sent to a triethylamine testing tank for testing, and after passing the test, the triethylamine is recovered.

[0014] Compared with the prior art, the present invention has the following advantages: The present invention is reasonably designed, effectively reduces the production cost of synthesizing 4,6-dichloro-5-fluoropyrimidine, reduces the amount of "three wastes", and recovers and reuses the acid-binding agent triethylamine, while improving the production environment for treating catalysts during the production process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a flowchart of the present invention.

[0016] In the picture: 1-Reaction vessel; 2-Filter press; 3-Neutralization vessel; 4-Distillation vessel; 5-Receiving tank; 6-Triethylamine tank; 7-Dichloroethane tank; 8-Alkali tank; 9-Aqueous phase receiving tank; 10-Organic phase receiving tank; 11-Condenser; 12-Mother liquor receiving tank; 13-Mother liquor transfer pump; 14-Aqueous phase transfer pump; 15-Triethylamine testing tank; 16-Triethylamine transfer pump; 17-Organic phase transfer pump. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0019] Table 1. Triethylamine components of the acid-binding agent before and after recovery.

[0020] Triethylamine salts are almost slightly soluble in dichloroethane; phosphorus oxychloride, 4,6-dichloroethane, etc., are readily soluble in dichloroethane. Note: At 25°C, 100 grams of dichloroethane can dissolve less than 0.01 grams of triethylamine salt.

[0021] like Figures 1-2As shown, this invention relates to a triethylamine recovery device in the production of 4,6-dichloro-5-fluoropyrimidine, comprising a reaction vessel 1, a filter press 2, a neutralization vessel 3, a distillation vessel 4, and a receiving tank 5. The feed end of the reaction vessel 1 is connected to a triethylamine tank 6 and a dichloroethane tank 7. The triethylamine acid salt solid (material composition as shown in Table 1 above) output from the triethylamine tank 6 is washed with dichloroethane in the reaction vessel 1. The discharge end of the reaction vessel 1 is connected to the feed end of the filter press 2, and the mixed liquid output from the reaction vessel is sent to the filter press for solid-liquid separation. The solid material output end of the filter press 2 is connected to the feed end of the neutralization vessel 3, i.e., the solid material is sent into the neutralization vessel. The neutralization process... The feed end of the reactor 3 is also connected to the alkali tank 8, which feeds alkali into the neutralization reactor. The alkali comes into contact with the solid material to form a mixture. The discharge end of the neutralization reactor 3 is connected to an aqueous phase receiving tank 9 and an organic phase receiving tank 10 arranged in parallel. The aqueous phase receiving tank is used to receive the aqueous phase discharged from the neutralization reactor, and the organic phase receiving tank is used to receive the organic matter discharged from the neutralization reactor. The output end of the organic phase receiving tank 10 is connected to the input end of the distillation reactor 4. The distillation reactor distills the organic matter output from the organic phase receiving tank to obtain gaseous triethylamine. The input end of the receiving tank 5 is connected to the upper end of the distillation reactor 4 through a condenser 11. The gaseous triethylamine discharged from the distillation reactor 4 is cooled by the condenser 11 and then enters the receiving tank 5.

[0022] The working principle of this invention is as follows: The materials listed in Table 1 are cooled and filtered. The filtered solid is then washed with 1.5-2 times its weight of triethylamine salt solid in dichloroethane to perform solid-liquid separation. The filtered solid is then added to liquid alkali, and the pH of the mixed liquid is controlled to be greater than 10. The mixture is allowed to stand and separate into layers, with the lower layer being organic matter. The lower layer of organic matter is extracted, and the separated organic matter is subjected to atmospheric pressure distillation to remove water and impurities, recovering triethylamine. After passing the test, it can be recycled for the synthesis of the next batch of 4,6-dichloro-5-fluoropyrimidine.

[0023] Specifically, in the reactor 1, the weight of dichloroethane is 1.5-2 times the weight of the triethylamine acid salt solid acid salt.

[0024] Specifically, the discharge end of the filter press 2 is connected to the mother liquor receiving tank 12, and the output end of the mother liquor receiving tank 12 is connected to the post-processing device through the mother liquor transfer pump 13. The mother liquor is then transported to the post-processing device for processing by the mother liquor transfer pump.

[0025] Specifically, the output end of the water phase receiving tank 9 is connected to a water phase transfer pump 14, which transports the water phase in the water phase receiving tank 9 to the sewage treatment plant.

[0026] Specifically, the discharge end of the receiving tank 5 is connected to the triethylamine testing tank 15, and the discharge end of the triethylamine testing tank 15 is connected to the triethylamine transfer pump 16.

[0027] Specifically, the reaction vessel, neutralization vessel, and distillation vessel are all equipped with a stirrer.

[0028] The process for producing triethylamine in 4,6-dichloro-5-fluoropyrimidine includes the following steps: (1) Triethylamine salt solid is fed into the reactor from a triethylamine tank, and dichloroethane is fed into the reactor from a dichloroethane tank. The weight of dichloroethane is 1.5-2 times the weight of the triethylamine salt solid. The triethylamine salt solid is washed with dichloroethane. (2) The material output from the reactor enters a filter press for solid-liquid separation. The separated solid is sent into a neutralization vessel. (3) Alkali solution is fed into the neutralization vessel from an alkali tank. The solid and alkali solution form a mixed liquid. The mixed liquid is then... The liquid pH value is controlled to be greater than 10, and then it is allowed to stand and separate into layers. The upper layer is organic matter; (4) the organic matter in the upper layer of the neutralization vessel is extracted and separated into an organic phase receiving tank, while the aqueous phase is sent into an aqueous phase receiving tank; (5) the organic matter in the organic phase receiving tank is sent into a distillation vessel for distillation; (6) the gaseous triethylamine discharged from the distillation vessel is condensed by a condenser and sent into a receiving tank; (7) the triethylamine in the receiving tank is sent into a triethylamine testing tank for testing, and after passing the test, the triethylamine is recovered and used for the synthesis of the next batch of 4,6-dichloro-5-fluoropyrimidine.

[0029] Example (1) Reaction Add 210 kg of dihydroxypyrimidine A, 1200 kg of dichloroethane B, and 800 kg of phosphorus oxychloride C to a 3000 L reactor and stir while cooling to 30 °C. Slowly add 210 kg of triethylamine dropwise. After the addition is complete, slowly raise the temperature to 80 °C until reflux occurs. Keep the mixture at this temperature and stir for 6 hours. After the reaction is completed, lower the temperature of the mixture to 50 °C. (2) Filtration The cooled material is quickly fed into a filter press. After the solids and liquids are completely separated, 420 kg of solids are washed from the filter press with 200 kg of dichloroethane. The filtered liquid is transferred to the 4,6-dichloro-5-fluoropyrimidine post-treatment unit using a mother liquor transfer pump p-01. (3) Neutralization and stratification After pressing, the solids are transferred from the filter press and then slowly added to a neutralization vessel containing 500 kg of 30% liquid alkali. The pH value is adjusted to 10-11. After stirring for 1 hour, the pH value is confirmed. Then, the mixture is allowed to stand for 30 minutes to separate into layers: an organic layer on top and a water layer on the bottom. The water layer is separated and transferred to the wastewater treatment plant using a water phase transfer pump. (4) Distillation recovery Then transfer the upper organic layer of about 210 kg to the distillation kettle, open the steam inlet and outlet valves of the distillation kettle jacket, control the kettle temperature at 100-120℃ and atmospheric pressure, distill off 195 kg of triethylamine, take a sample for analysis, the moisture content is less than 0.5%, and it is qualified to be used for the next batch.

[0030] This embodiment utilizes the characteristic that triethylamine salts are not difficult to dissolve in dichloroethane. Before quenching, it is separated into solid and liquid phases, and then the separated solid is neutralized in a targeted manner, reducing the amount of water and alkali used and increasing the recovery rate of triethylamine by about 91%.

[0031] Comparative Example 1.1 Reaction 210 kg of dihydroxypyrimidine A, 1200 kg of dichloroethane B, and 800 kg of phosphorus oxychloride C were added to a 3000 L reactor a-01 and stirred until the temperature was lowered to 30 °C. 210 kg of triethylamine was then slowly added dropwise. After the addition was complete, the temperature was slowly raised to 80 °C until reflux occurred. The mixture was kept at this temperature and stirred for 6 hours. After the reaction was completed, the temperature was lowered to 50 °C and added dropwise to a quenching vessel containing 2000 kg of water, maintaining the temperature at 40 °C. After the quenching was completed, the mixture was stirred and allowed to stand for 1 hour to separate into layers. The oil layer (main components: dichloroethane; 4,6-dichloro-5-fluoropyrimidine) was further processed, while the water layer (containing triethylamine acid salt, phosphoric acid, hydrochloric acid, etc.) was sent to a wastewater treatment plant. The comparative sample did not filter the triethylamine salt but dissolved it directly in water. The aqueous phase contained a high acid content, and the wastewater treatment required a large amount of alkali.

[0032] This invention can convert the acid-binding agent triethylamine into a recyclable material. Based on an annual production of 200 tons of 4,6-dichloro-5-fluoropyrimidine, the recovered triethylamine is shown in the table below.

[0033] This invention reduces the cost of synthesizing 4,6-dichloro-5-fluoropyrimidine and also improves the production environment for handling catalysts when producing this product.

[0034] If this invention discloses or relates to components or structural parts that are fixedly connected to each other, then, unless otherwise stated, a fixed connection can be understood as: a fixed connection that can be detached (e.g., using bolts or screws), or a fixed connection that cannot be detached (e.g., riveting, welding). Of course, a fixed connection can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0035] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0036] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A device for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine, characterized in that: The apparatus includes a reaction vessel, a filter press, a neutralization vessel, a distillation vessel, and a receiving tank. The feed end of the reaction vessel is connected to a triethylamine tank and a dichloroethane tank. The triethylamine acid salt solid output from the triethylamine tank is washed with dichloroethane in the reaction vessel. The discharge end of the reaction vessel is connected to the feed end of the filter press. The solid material output end of the filter press is connected to the feed end of the neutralization vessel. The feed end of the neutralization vessel is also connected to an alkali tank. The discharge end of the neutralization vessel is connected to a parallel aqueous phase receiving tank and an organic phase receiving tank. The output end of the organic phase receiving tank is connected to the input end of the distillation vessel. The input end of the receiving tank is connected to the upper end of the distillation vessel through a condenser. The gaseous triethylamine discharged from the distillation vessel is cooled by the condenser and then enters the receiving tank.

2. The device for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine according to claim 1, characterized in that: Inside the reactor, the weight of dichloroethane is 1.5-2 times that of the triethylamine salt solid.

3. The device for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine according to claim 1, characterized in that: The filter press's discharge end is connected to the mother liquor receiving tank, and the output end of the mother liquor receiving tank is connected to the post-processing device via a mother liquor transfer pump.

4. The apparatus for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine according to claim 1, characterized in that: The output end of the aqueous phase receiving tank is connected to an aqueous phase transfer pump, which transports the aqueous phase in the aqueous phase receiving tank to the sewage treatment plant.

5. A device for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine according to claim 1, characterized in that: The discharge end of the receiving tank is connected to the triethylamine testing tank, and the discharge end of the triethylamine testing tank is connected to a triethylamine delivery pump.

6. The apparatus for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine according to claim 1, characterized in that: The reaction vessel, neutralization vessel, and distillation vessel are all equipped with stirrers.

7. A process for recovering triethylamine in the production of 4,6-dichloro-5-fluoropyrimidine, characterized in that: The device includes a triethylamine recovery apparatus for the production of 4,6-dichloro-5-fluoropyrimidine as described in any one of claims 1-6, comprising the following steps: (1) a triethylamine tank conveys triethylamine acid salt solid into a reaction vessel, and a dichloroethane tank conveys dichloroethane into the reaction vessel, thereby rinsing the triethylamine acid salt solid with dichloroethane; (2) the material output from the reaction vessel enters a filter press for solid-liquid separation, and the separated solid is sent into a neutralization vessel; (3) an alkali tank feeds alkali solution into the neutralization vessel. The solid and the alkaline solution form a mixed liquid, which is then allowed to stand and separate into layers. The upper layer is organic matter. (4) The organic matter in the upper layer of the neutralization vessel is extracted and separated into an organic phase receiving tank, while the aqueous phase is sent into an aqueous phase receiving tank. (5) The organic matter in the organic phase receiving tank is sent to a distillation vessel for distillation. (6) The gaseous triethylamine discharged from the distillation vessel is condensed by a condenser and sent into a receiving tank. (7) The triethylamine in the receiving tank is sent to a triethylamine testing tank for testing. After passing the test, the triethylamine is recovered.

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