Dipterex production device and process

Abstract

The invention relates to the technical field of organic synthesis, in particular to a trichlorfon production device and a trichlorfon production process, the device comprises a first-stage synthesis kettle, a first-stage synthesis kettle condenser, a second-stage synthesis kettle, a second-stage synthesis kettle condenser and a centrifugal machine; a trichloroacetaldehyde feeding hole, a dimethyl phosphite feeding hole and a precipitant feeding hole are formed in the top of the first-stage synthesis kettle, an overflow hole is formed in the upper part of the side wall of the first-stage synthesis kettle, and the top of the first-stage synthesis kettle is connected with a first-stage synthesis kettle condenser through a pipeline; the second-stage synthesis kettle is communicated with an overflow port of the first-stage synthesis kettle through an overflow pipe, and the top of the second-stage synthesis kettle is connected with a second-stage synthesis kettle condenser through a pipeline; and the centrifugal machine is communicated with an overflow port of the second-stage synthesis kettle through an overflow pipe. According to the invention, a continuous synthesis method is adopted, and solid trichlorfon is immediately precipitated and separated out by adding a precipitant; meanwhile, two stages of synthesis kettles are arranged, so that solid trichlorfon is precipitated and separated out more sufficiently while the reaction retention time is ensured, the trichlorfon content is greater than or equal to 98%, and the yield is greater than or equal to 90%.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a trichlorfon production device and process. Background Technology

[0002] Trichlorfon, in its pure form, is a colorless needle-like crystal with a melting point of 83-84℃. It is readily soluble in water, alcohols, benzene, and most chlorinated hydrocarbons, slightly soluble in ether and carbon tetrachloride, and has low solubility in aliphatic hydrocarbon solvents. The technical grade of trichlorfon is mainly prepared by a one-step reaction of dimethyl phosphite and trichloroacetaldehyde, yielding a technical grade with a purity of approximately 90%. Refined trichlorfon typically requires salting out or recrystallization in water.

[0003] Chinese invention patent CN102234292B discloses a method for preparing refined trichlorfon using trichlorfon technical as a solute and trichloroethylene as a solvent, through mixing, dissolving, recrystallizing, filtering, and drying. The trichlorfon yield of this method is 83.8%. This method belongs to the common method for refining trichlorfon and does not involve any improvement in the synthetic preparation method. Chinese invention patent CN102464674B discloses a method for preparing trichlorfon technical. This method involves washing approximately 93% of the trichlorfon semi-finished product with water, cooling crystallization, centrifugation, separation, and drying to obtain trichlorfon technical 1 with a content ≥97% and a water washing mother liquor. The water washing mother liquor is then treated by salting out to obtain trichlorfon technical 2 with a content ≥90% and a salting out mother liquor, which is then sent to the post-processing flow.

[0004] However, salting out introduces impurities such as sodium ions into the finished trichlorfon product, which limits the production of products with high trichlorfon content requirements. The current mainstream process involves washing with large amounts of water or recycled mother liquor, followed by rapid cooling and recrystallization at 0-5°C to prepare refined trichlorfon. Existing refining methods achieve a trichlorfon yield of around 80%, but the low-temperature conditions result in high energy consumption and generate large amounts of phosphorus-containing washing wastewater. Summary of the Invention

[0005] To address the problems in existing technologies, reduce wastewater generation during trichlorfon synthesis, and improve the yield of solid trichlorfon, the inventors sought a solvent with low or no solubility for trichlorfon. This solvent would precipitate trichlorfon from the solvent simultaneously with its formation during synthesis, maximizing the extraction of the generated trichlorfon, minimizing material loss due to dissolution, and increasing product yield. Furthermore, the precipitant could be recovered and reused in the synthesis system, further reducing wastewater generation in existing processes. Through literature review and experimental verification, the inventors discovered that trichlorfon has low solubility in aliphatic hydrocarbon solvents or non-polar haloalkane solvents, enabling simultaneous synthesis and precipitation.

[0006] The first aspect of the present invention provides a trichlorfon production apparatus, the apparatus comprising a primary synthesis reactor, a primary synthesis reactor condenser, a secondary synthesis reactor, a secondary synthesis reactor condenser, and a centrifuge; The top of the primary synthesis reactor is equipped with a trichloroacetaldehyde inlet, a dimethyl phosphite inlet, and a precipitant inlet, and the upper part of the side wall is equipped with an overflow port. The top is connected to the condenser of the primary synthesis reactor through a pipe. The secondary synthesis reactor is connected to the overflow port of the primary synthesis reactor via an overflow pipe, and its top is connected to the condenser of the secondary synthesis reactor via a pipe. The centrifuge is connected to the overflow port of the secondary synthesis reactor via an overflow pipe.

[0007] A second aspect of the present invention provides a process for producing trichlorfon, comprising the following steps: S1. Trichloroacetaldehyde, dimethyl phosphite and precipitant are simultaneously introduced into the primary synthesis reactor and stirred to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

[0008] In one embodiment, before introducing trichloroacetaldehyde, dimethyl phosphite and the precipitant in step S1, a precipitant layer of 1 / 3 to 1 / 2 of the volume of the synthesis reactor is first added to the bottom of the primary synthesis reactor.

[0009] In one embodiment, the precipitant comprises an aliphatic hydrocarbon solvent or a nonpolar haloalkane solvent.

[0010] In one embodiment, the aliphatic hydrocarbon solvent includes at least one selected from hexane, heptane, octane, nonane, decane, and petroleum ether.

[0011] In one embodiment, the hexane is n-hexane.

[0012] In one embodiment, the nonpolar haloalkane solvent includes carbon tetrachloride.

[0013] In one embodiment, the feed molar ratio of trichloroacetaldehyde and dimethyl phosphite in step S1 is 1:(0.98-1.02).

[0014] In one embodiment, the mass ratio of trichloroacetaldehyde to precipitant in step S1 is 1:(2-6). Examples include 1:2, 1:3, 1:4, 1:5, and 1:6.

[0015] In one embodiment, the reaction temperature of the primary synthesis reactor in step S1 is 50-70°C, and the stirring rate is 100-150 r / min.

[0016] In one embodiment, the reaction temperature of the primary synthesis reactor in step S1 is 55-65°C, and the stirring rate is 100-150 r / min.

[0017] In one embodiment, the reaction temperature of the primary synthesis reactor in step S1 is 65°C, and the stirring rate is 100 r / min.

[0018] In one embodiment, the residence time of trichloroacetaldehyde, dimethyl phosphite, and the precipitant in the primary synthesis reactor during step S1 is 0.5-3 hours. Examples include 0.5 hours, 1 hour, 2 hours, and 3 hours.

[0019] In one embodiment, the reaction temperature of the secondary synthesis reactor is 30-50°C, and the stirring rate is 50-100 r / min.

[0020] In one embodiment, the reaction temperature of the secondary synthesis reactor is 35-45°C, and the stirring rate is 50-100 r / min.

[0021] In one embodiment, the reaction temperature of the secondary synthesis reactor is 35°C, and the stirring rate is 50 r / min.

[0022] In this application, the number of centrifuges is determined according to production requirements. In one embodiment, two or three centrifuges are used.

[0023] This application utilizes a primary synthesis reactor condenser and a secondary synthesis reactor condenser to condense and recover the steam generated during the reaction process, effectively preventing the emission of harmful gases and meeting environmental protection requirements. Simultaneously, this condensation recovery system also condenses low-boiling-point components that volatilize during the reaction, reducing material loss, lowering production costs, and improving resource utilization.

[0024] The centrifuged mother liquor obtained after centrifugation in this application is recycled and reused in the primary synthesis reactor.

[0025] Beneficial effects 1. This invention, through the addition of a specific precipitant, particularly by selecting aliphatic hydrocarbon solvents or non-polar haloalkane solvents, can cause trichlorfon to precipitate out immediately. Moreover, the precipitant does not react with trichlorfon, and no impurities are introduced, thereby increasing the content of the finished trichlorfon product.

[0026] 2. This invention controls the feed mass ratio of trichloroacetaldehyde and precipitant to be 1:(2-6), which can achieve a certain washing effect while precipitating trichlorfon, effectively increasing the trichlorfon content. If there is too much precipitant, it will increase the subsequent centrifugation load, causing energy waste, and will also lead to increased trichlorfon dissolution, affecting product yield and causing raw material waste. If there is too little precipitant, it will increase the trichlorfon solid content in the synthesis vessel, affecting the precipitation effect.

[0027] 3. This invention features a two-stage synthesis reactor, which ensures sufficient reaction residence time while allowing for more complete precipitation of solid trichlorfon, thereby improving product yield.

[0028] 4. This invention controls the temperature of the two-stage synthesis reactor. Controlling the temperature of the first-stage synthesis reactor at 50-70℃ provides reaction activation energy, promoting rapid and complete reaction of raw materials. Controlling the temperature of the second-stage synthesis reactor at 30-50℃ helps solid trichlorfon to further precipitate in the precipitant, thereby improving product yield.

[0029] 5. Compared with the traditional method of synthesizing trichlorfon, this method adopts a continuous synthesis method to synthesize refined trichlorfon in one step, avoiding the large amount of difficult-to-treat phosphorus-containing wastewater generated by the traditional water washing process, which is more environmentally friendly and efficient; no hazardous waste is generated, and the trichlorfon content is ≥98% and the yield is ≥90%. Attached Figure Description

[0030] Figure 1 This is a trichlorfon production facility. It includes: 1. a primary synthesis reactor; 2. a primary synthesis reactor condenser; 3. a secondary synthesis reactor; 4. a secondary synthesis reactor condenser; and 5. a centrifuge. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Experimental methods not specifying specific conditions in the embodiments were performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0032] The trichloroacetaldehyde (≥96.5%), dimethyl phosphite (≥98%), carbon tetrachloride (≥97.0%), methanol (≥99.5%), and n-hexane (≥97.0%) used in the following examples and comparative examples are all industrial-grade finished products.

[0033] Example 1 The first aspect of this example provides a dichlorvos production device, such as... Figure 1 As shown, the apparatus includes a primary synthesis reactor 1, a primary synthesis reactor condenser 2, a secondary synthesis reactor 3, a secondary synthesis reactor condenser 4, and a centrifuge 5; The top of the primary synthesis reactor 1 is provided with a trichloroacetaldehyde inlet, a dimethyl phosphite inlet, and a precipitant inlet, and the upper part of the side wall is provided with an overflow port. The top is connected to the primary synthesis reactor condenser 2 through a pipe. The secondary synthesis reactor 3 is connected to the overflow port of the primary synthesis reactor 1 through an overflow pipe, and its top is connected to the secondary synthesis reactor condenser 4 through a pipe. The centrifuge 5 is connected to the overflow port of the secondary synthesis reactor 3 via an overflow pipe.

[0034] The second aspect of this example provides a process for producing trichlorfon, including the following steps: S1. Add 2 tons of precipitant to the primary synthesis reactor and preheat to 50°C. Then, introduce trichloroacetaldehyde, dimethyl phosphite, and the precipitant into the primary synthesis reactor at flow rates of 0.87 tons / hour, 0.65 tons / hour, and 3.48 tons / hour, respectively, and stir to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

[0035] The centrifuged mother liquor obtained after centrifugation is recovered and reused as a precipitant in the primary synthesis reactor.

[0036] The centrifuges are configured to be 3 units.

[0037] The precipitant is n-hexane.

[0038] In step S1, the reaction temperature in the primary synthesis reactor is 65°C, and the stirring rate is 100 r / min. In step S1, the residence time of trichloroacetaldehyde, dimethyl phosphite, and the precipitant in the primary synthesis reactor is 1 hour. The reaction temperature in the secondary synthesis reactor is 35℃, and the stirring rate is 50r / min.

[0039] In this example, the trichlorfon content was 98.3%, and the yield was 92.4%.

[0040] Example 2 The specific implementation method of this example is the same as that of Example 1, except that the second aspect of this example provides a trichlorfon production process, including the following steps: S1. Add 2 tons of precipitant to the primary synthesis reactor and preheat to 50°C. Then, introduce trichloroacetaldehyde, dimethyl phosphite, and the precipitant into the primary synthesis reactor at flow rates of 0.43 tons / hour, 0.33 tons / hour, and 1.74 tons / hour, respectively, and stir to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

[0041] The centrifuged mother liquor obtained after centrifugation is recovered and reused as a precipitant in the primary synthesis reactor.

[0042] Two centrifuges are configured.

[0043] The precipitant is n-hexane.

[0044] In step S1, the reaction temperature in the primary synthesis reactor is 65°C, and the stirring rate is 100 r / min. In step S1, the residence time of trichloroacetaldehyde, dimethyl phosphite, and the precipitant in the primary synthesis reactor is 2 hours. The reaction temperature in the secondary synthesis reactor is 35℃, and the stirring rate is 50r / min.

[0045] In this example, the trichlorfon content was 98.5%, and the yield was 93.8%.

[0046] Example 3 The specific implementation method of this example is the same as that of Example 1, except that the second aspect of this example provides a trichlorfon production process, including the following steps: S1. Add 2 tons of precipitant to the primary synthesis reactor and preheat to 60°C. Then, introduce trichloroacetaldehyde, dimethyl phosphite, and the precipitant into the primary synthesis reactor at flow rates of 0.87 tons / hour, 0.65 tons / hour, and 3.84 tons / hour, respectively, and stir to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

[0047] The centrifuged mother liquor obtained after centrifugation is recovered and reused as a precipitant in the primary synthesis reactor.

[0048] The centrifuges are configured to be 3 units.

[0049] The precipitant is carbon tetrachloride.

[0050] In step S1, the reaction temperature in the primary synthesis reactor is 70°C, and the stirring rate is 100 r / min. In step S1, the residence time of trichloroacetaldehyde, dimethyl phosphite, and the precipitant in the primary synthesis reactor is 1 hour. The reaction temperature in the secondary synthesis reactor is 40℃, and the stirring rate is 50r / min.

[0051] In this example, the trichlorfon content was 98.1%, and the yield was 90.3%.

[0052] Comparative Example 1 The specific implementation method in this example is the same as in Example 1, except that this example provides a trichlorfon production process, including the following steps: S1. Add 2 tons of precipitant to the primary synthesis reactor and preheat to 50°C. Then, introduce trichloroacetaldehyde, dimethyl phosphite, and the precipitant into the primary synthesis reactor at flow rates of 1.95 tons / hour, 1.47 tons / hour, and 7.83 tons / hour, respectively, and stir to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

[0053] The centrifuged mother liquor obtained after centrifugation is recovered and reused as a precipitant in the primary synthesis reactor.

[0054] The centrifuges are configured to be 3 units.

[0055] The precipitant is n-hexane.

[0056] In step S1, the reaction temperature in the primary synthesis reactor is 65℃, and the stirring rate is 100 r / min. In step S1, the residence time of trichloroacetaldehyde, dimethyl phosphite, and the precipitant in the primary synthesis reactor is 0.44 h. The reaction temperature in the secondary synthesis reactor is 35℃, and the stirring rate is 50r / min.

[0057] In this example, the trichlorfon content was 97%, and the yield was 84.3%.

[0058] Comparative Example 2 The specific implementation method in this example is the same as in Example 1, except that this example provides a trichlorfon production process, including the following steps: S1. Add 2 tons of precipitant to the primary synthesis reactor and preheat to 50°C. Then, introduce trichloroacetaldehyde, dimethyl phosphite, and the precipitant into the primary synthesis reactor at flow rates of 0.87 tons / hour, 0.65 tons / hour, and 3.48 tons / hour, respectively, and stir to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

[0059] The centrifuged mother liquor obtained after centrifugation is recovered and reused as a precipitant in the primary synthesis reactor.

[0060] The centrifuges are configured to be 3 units.

[0061] The precipitant is n-hexane.

[0062] In step S1, the reaction temperature in the primary synthesis reactor is 65°C, and the stirring rate is 100 r / min. In step S1, the residence time of trichloroacetaldehyde, dimethyl phosphite, and the precipitant in the primary synthesis reactor is 1 hour. The reaction temperature in the secondary synthesis reactor is 65℃, and the stirring rate is 50r / min.

[0063] In this example, the trichlorfon content was 98%, and the yield was 78.8%.

[0064] Comparative Example 3 The specific implementation method in this example is the same as in Example 1, except that this example provides a trichlorfon production process, including the following steps: S1. Add 2 tons of precipitant to the primary synthesis reactor and preheat to 50°C. Then, introduce trichloroacetaldehyde, dimethyl phosphite, and the precipitant into the primary synthesis reactor at flow rates of 0.87 tons / hour, 0.65 tons / hour, and 0.87 tons / hour, respectively, and stir to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

[0065] The centrifuged mother liquor obtained after centrifugation is recovered and reused as a precipitant in the primary synthesis reactor.

[0066] The centrifuges are configured to be 3 units.

[0067] The precipitant is n-hexane.

[0068] In step S1, the reaction temperature in the primary synthesis reactor is 65°C, and the stirring rate is 100 r / min. In step S1, the residence time of trichloroacetaldehyde, dimethyl phosphite, and the precipitant in the primary synthesis reactor is 2 hours. The reaction temperature in the secondary synthesis reactor is 35℃, and the stirring rate is 50r / min.

[0069] In this example, the trichlorfon content was 96.3%, and the yield was 65.3%.

[0070] Comparative Example 4 The specific implementation method in this example is the same as in Example 1, except that no precipitant is added in this example.

[0071] Testing revealed that the material content in the secondary synthesis reactor in this case was approximately 91.8%. Since no precipitant was added, it could not precipitate and purify the trichlorfon, and could only be used as a technical grade of trichlorfon with a purity of approximately 90%.

[0072] Comparative Example 5 The specific implementation method in this example is the same as in Example 1, except that the precipitant used in this example is methanol. Because trichlorfon has high solubility in alcohol solvents, the trichlorfon produced in the synthesis reaction dissolves in the precipitant and cannot precipitate as a solid.

Claims

1. A dichlorvos production device, characterized in that, The apparatus includes a primary synthesis reactor, a primary synthesis reactor condenser, a secondary synthesis reactor, a secondary synthesis reactor condenser, and a centrifuge; The top of the primary synthesis reactor is equipped with a trichloroacetaldehyde inlet, a dimethyl phosphite inlet, and a precipitant inlet, and the upper part of the side wall is equipped with an overflow port. The top is connected to the condenser of the primary synthesis reactor through a pipe. The secondary synthesis reactor is connected to the overflow port of the primary synthesis reactor via an overflow pipe, and its top is connected to the condenser of the secondary synthesis reactor via a pipe. The centrifuge is connected to the overflow port of the secondary synthesis reactor via an overflow pipe.

2. A process for producing trichlorfon, characterized in that, The trichlorfon production process uses the production apparatus described in claim 1, and the trichlorfon production process includes the following steps: S1. Trichloroacetaldehyde, dimethyl phosphite and precipitant are simultaneously introduced into the primary synthesis reactor and stirred to form a reaction solution. S2. The reaction solution enters the secondary synthesis reactor through the overflow pipe for continuous reaction, and then enters the centrifuge through the overflow pipe. After centrifugation and drying, the trichlorfon is obtained.

3. The trichlorfon production process according to claim 2, characterized in that, The precipitant includes aliphatic hydrocarbon solvents or nonpolar haloalkane solvents.

4. The trichlorfon production process according to claim 3, characterized in that, The aliphatic hydrocarbon solvent includes at least one of hexane, heptane, octane, nonane, decane, and petroleum ether.

5. The trichlorfon production process according to claim 3, characterized in that, The nonpolar haloalkane solvent includes carbon tetrachloride.

6. The trichlorfon production process according to claim 2, characterized in that, In step S1, the feed molar ratio of trichloroacetaldehyde and dimethyl phosphite is 1:(0.98-1.02).

7. The trichlorfon production process according to claim 6, characterized in that, In step S1, the mass ratio of trichloroacetaldehyde to precipitant is 1:(2-6).

8. The trichlorfon production process according to claim 2, characterized in that, In step S1, the reaction temperature in the primary synthesis reactor is 50-70℃, and the stirring rate is 100-150 r / min.

9. The trichlorfon production process according to claim 2, characterized in that, In step S1, the residence time of trichloroacetaldehyde, dimethyl phosphite, and precipitant in the primary synthesis reactor is 0.5-3 hours.

10. The trichlorfon production process according to claim 2, characterized in that, The reaction temperature in the secondary synthesis reactor is 30-50℃, and the stirring rate is 50-100 r / min.

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