Efficient and continuous trimethyl phosphite production device and process

Abstract

The invention relates to the technical field of organic synthesis, in particular to a trimethyl phosphite efficient continuous production device and process, the device comprises a solvent tank, a precooler, a methanol tank, a circulating pump, a phosphorus trichloride tank, a circulating flow reactor, a circulating kettle, an alkali precooler, a water washing kettle, a layering system and a rectification system; the solvent tank is connected with the precooler through a pipeline, the precooler, the methanol tank and the phosphorus trichloride tank are respectively connected with the circulating flow reactor through pipelines, the circulating kettle is in closed-loop connection with the circulating flow reactor through a circulating pump and a pipeline, and the alkali precooler is connected with the washing kettle through a pipeline. And the washing kettle is connected with the rectification system through a pipeline by virtue of the layering system. The circulating flow reactor is arranged in the continuous device, and the temperatures of the circulating kettle, the circulating flow reactor and the washing kettle and the feeding flow of the raw materials are controlled, so that high-efficiency conversion of the materials can be realized, the content of the prepared trimethyl phosphite is more than or equal to 99.5%, and the yield is more than or equal to 95%.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a high-efficiency continuous production device and process for trimethyl phosphite. Background Art

[0002] As a key intermediate in pesticide synthesis, trimethyl phosphite is widely used in the production of various vinyl phosphate insecticides such as phosphamidon, monocrotophos, and dichlorvos, and also plays an important role in the manufacture of flame retardants.

[0003] At present, the mainstream method for synthesizing trimethyl phosphite is to react phosphorus trichloride with methanol in the presence of an acid binding agent. This process is intended to prevent the generated hydrogen chloride from acidolyzing trimethyl phosphite. The general feeding method is to pass two streams of phosphorus trichloride and methanol mixture into the nozzle in the same direction and enter the reactor for mixed reaction. However, if the two streams of materials cannot be dispersed quickly after contact, the conversion rate of the product may be reduced. In addition, the thinner nozzle is easily blocked by solid impurities in phosphorus trichloride and ammonium salts generated by the reaction, which will have an adverse effect on the production process.

[0004] Chinese invention patent CN100376589C discloses a process for producing trimethyl phosphite, which uses an enamel reactor with xylene as solvent and N,N-dimethylaniline as acid-binding agent, and the product purity reaches 98-99.8%, and the yield reaches 88-89% based on phosphorus trichloride. However, this method is a common kettle reaction, and the mass transfer and heat transfer effect is limited, which affects the raw material conversion rate. Summary of the invention

[0005] In order to solve the problems in the prior art, the first aspect of the present invention provides a high-efficiency continuous production device for trimethyl phosphite, which includes a solvent tank, a precooler, a methanol tank, a circulation pump, a phosphorus trichloride tank, a circulating flow reactor, a circulating kettle, an alkali precooler, a water washing kettle, a stratification system, and a distillation system; the solvent tank is connected to the precooler through a pipeline, the precooler, the methanol tank, and the phosphorus trichloride tank are respectively connected to the circulating flow reactor through pipelines, the circulating kettle is closed-loop connected to the circulating flow reactor through a pipeline via the circulation pump, the alkali precooler is connected to the water washing kettle through a pipeline, and the water washing kettle is connected to the distillation system through a pipeline via the stratification system.

[0006] In one embodiment, a pipeline is provided at the overflow port of the circulation kettle to connect with the water washing kettle.

[0007] The second aspect of the present invention provides a high-efficiency continuous production process of trimethyl phosphite, comprising the following steps:

[0008] S1, pre-adding alkaline solution into the washing kettle;

[0009] S2, precooling the solvent in the solvent tank through a precooler and then feeding it to the outlet of the circulation pump through a pipeline;

[0010] S3, after the material level in the circulating kettle rises to 50% of the overall height of the circulating kettle, the circulating pump is turned on to form circulating materials;

[0011] S4, the methanol in the methanol tank is mixed with the solvent in S2 through a pipeline and then fed to the outlet of the circulation pump through a pipeline; at the same time, the phosphorus trichloride in the phosphorus trichloride tank is added perpendicularly to the circulating material at the inlet of the circulating flow reactor to react;

[0012] S5. After the liquid level in the circulating kettle rises to the overflow port, the material overflows into the water washing kettle and reacts with the alkaline solution in the water washing kettle. The reaction liquid passes through the stratification system and the distillation system in sequence through the pipeline to finally produce trimethyl phosphite.

[0013] The applicant has found that by adding phosphorus trichloride material perpendicular to the circulating material at the inlet of the circulating flow reactor, the large flow of circulating material can effectively disperse the phosphorus trichloride fed at the reactor inlet, achieve efficient conversion of the material, avoid the risk of clogging of the feed nozzle after long-term operation, and reduce the impact on continuous production.

[0014] In one embodiment, the feed flow rate of the alkaline solution in step S1 is 1.5-3.5 tons / hour.

[0015] In one embodiment, the feed flow rate of the alkaline solution in step S1 is 2.5 tons / hour.

[0016] In one embodiment, the alkaline solution in step S1 is a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 15 wt %.

[0017] In one embodiment, the solvent in step S2 comprises an organic solvent and an acid binding agent, and the mass ratio of the organic solvent to the acid binding agent is 1:(3-7).

[0018] In one embodiment, the mass ratio of the organic solvent to the acid binding agent is 1:4.

[0019] In one embodiment, the organic solvent in step S2 is benzene.

[0020] In one embodiment, the acid binding agent in step S2 is triethylamine.

[0021] In one embodiment, the feed flow rate of the solvent in step S2 is 5.4-10 tons / hour.

[0022] In one embodiment, the feed flow rate of the solvent in step S2 is 7.3 tons / hour.

[0023] In one embodiment, the temperature of the circulating kettle is controlled at 50-65°C.

[0024] In one embodiment, the temperature of the circulating flow reactor is controlled at 50-65°C.

[0025] In one embodiment, the temperatures of the circulating kettle and the circulating flow reactor are both 62°C.

[0026] In one embodiment, the temperature of the water washing kettle is controlled at 0-15°C.

[0027] In one embodiment, the temperature of the water washing kettle is 10°C.

[0028] In one embodiment, the circulation flow rate of the circulation pump is 3-5 tons / hour.

[0029] In one embodiment, the circulation flow rate of the circulation pump is 4 tons / hour.

[0030] In one embodiment, the feed flow ratio of methanol to phosphorus trichloride is (2-4):(3-5).

[0031] In one embodiment, the feed flow ratio of methanol to phosphorus trichloride is 0.32:0.4.

[0032] In one embodiment, the feed flow rate of methanol is 0.2-0.4 ton / hour.

[0033] In one embodiment, the feed flow rate of methanol is 0.32 tons / hour.

[0034] In one embodiment, the feed rate of phosphorus trichloride is 0.3-0.5 ton / hour.

[0035] In one embodiment, the feed rate of phosphorus trichloride is 0.4 tons / hour.

[0036] Beneficial Effects

[0037] 1. The present invention adopts a circulating flow reactor, which can effectively remove the reaction heat and reduce the occurrence of side reactions. The content of the prepared trimethyl phosphite is ≥99.5%, and the yield is ≥95%.

[0038] 2. The efficient continuous production process of trimethyl phosphite provided by the present invention can achieve efficient conversion of materials by controlling the temperatures of the circulating kettle, the circulating flow reactor and the water washing kettle and the feed flow rate of the raw materials.

[0039] 3. The efficient and continuous production process of trimethyl phosphite provided by the present invention can avoid the risk of clogging of the feed nozzle after long-term operation by controlling the addition method of the phosphorus trichloride material, thereby reducing the impact on continuous production.

[0040] 4. The efficient and continuous production process of trimethyl phosphite provided by the present invention can fully utilize the raw materials, reduce the occurrence of side reactions, improve production efficiency and reduce costs.

[0041] 5. The efficient and continuous production process of trimethyl phosphite provided by the present invention is a continuous flow reaction throughout the reaction process, which avoids the potential safety hazards and environmental pollution caused by leakage during material transfer in conventional production, and is easy to prepare trimethyl phosphite industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a highly efficient continuous production device for trimethyl phosphite. It includes: 1. solvent tank; 2. precooler; 3. methanol tank; 4. circulating pump; 5. phosphorus trichloride tank; 6. circulating flow reactor; 7. circulating kettle; 8. alkali precooler; 9. water washing kettle; 10. stratification system; 11. distillation system. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the examples and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The experimental methods for which specific conditions are not specified in the examples are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be purchased commercially.

[0044] Example 1

[0045] The first aspect of this embodiment provides a high-efficiency continuous production device for trimethyl phosphite, such as Figure 1 As shown, the device includes a solvent tank 1, a precooler 2, a methanol tank 3, a circulating pump 4, a phosphorus trichloride tank 5, a circulating flow reactor 6, a circulating kettle 7, an alkali precooler 8, a water washing kettle 9, a stratification system 10, and a distillation system 11.

[0046] The solvent tank 1 is connected to the precooler 2 through a pipeline, the precooler 2, the methanol tank 3, and the phosphorus trichloride tank 5 are respectively connected to the circulating flow reactor 6 through pipelines, the circulating kettle 7 is closed-loop connected to the circulating flow reactor 6 through a pipeline via a circulating pump 4, the alkali precooler 8 is connected to the water washing kettle 9 through a pipeline, and the water washing kettle 9 is connected to the distillation system 11 through a pipeline via a stratification system 10.

[0047] The second aspect of the present embodiment provides a high-efficiency continuous production process of trimethyl phosphite, comprising the following steps:

[0048] S1. Pre-add 15 wt % sodium hydroxide solution into a water washing kettle, and the feed flow rate of the sodium hydroxide solution is 2.5 tons / hour.

[0049] S2, feeding the mixed solution of the organic solvent and the acid binding agent precooled by the precooler to the outlet of the circulation pump through a pipeline, and the feed flow rate of the mixed solution is 7.3 tons / hour;

[0050] S3, after the material level in the circulating kettle rises to 50% of the overall height of the circulating kettle, the circulating pump is turned on to form circulating materials;

[0051] S4, the methanol in the methanol tank is mixed with the mixed solution of S2 through a pipeline and then fed to the outlet of the circulation pump through a pipeline; at the same time, the phosphorus trichloride in the phosphorus trichloride tank is added perpendicularly to the circulating material at the inlet of the circulating flow reactor to react;

[0052] S5. After the liquid level in the circulating kettle rises to the overflow port, the material overflows into the water washing kettle and reacts with the alkaline solution in the water washing kettle. The reaction liquid passes through the stratification system and the distillation system in sequence through the pipeline to finally produce trimethyl phosphite.

[0053] In the step S2, the organic solvent is benzene and the acid binding agent is triethylamine.

[0054] The mass ratio of the organic solvent to the acid binding agent is 1:4, and the feed flow rate of benzene is 1.46 tons / hour.

[0055] The temperatures of the circulating kettle and the circulating flow reactor were both 62°C.

[0056] The circulation flow rate of the circulation pump is 4 tons / hour.

[0057] The feed flow rate of the methanol is 0.32 ton / hour, the feed flow rate of the phosphorus trichloride is 0.4 ton / hour, and the temperature of the water washing kettle is 10°C.

[0058] Comparative Example 1

[0059] The specific implementation of this comparative example is the same as that of Example 1, except that the second aspect of this comparative example provides a continuous production process of trimethyl phosphite, comprising the following steps:

[0060] S1. Pre-add 15 wt % sodium hydroxide solution into a water washing kettle, and the feed flow rate of the sodium hydroxide solution is 2.5 tons / hour.

[0061] S2, feeding the mixed solution of the organic solvent and the acid binding agent precooled by the precooler to the outlet of the circulation pump through a pipeline, and the feed flow rate of the mixed solution is 7.3 tons / hour;

[0062] S3, after the material level in the circulating kettle rises to 50% of the overall height of the circulating kettle, the circulating pump is turned on to form circulating materials;

[0063] S4, the methanol in the methanol tank is mixed with the mixed solution of S2 through a pipeline and then fed to the outlet of the circulation pump through a pipeline; at the same time, the phosphorus trichloride in the phosphorus trichloride tank is added perpendicularly to the circulating material at the inlet of the circulating flow reactor to react;

[0064] S5. After the liquid level in the circulating kettle rises to the overflow port, the material overflows into the water washing kettle and reacts with the alkaline solution in the water washing kettle. The reaction liquid passes through the stratification system and the distillation system in sequence through the pipeline to finally produce trimethyl phosphite.

[0065] In the step S2, the organic solvent is benzene and the acid binding agent is triethylamine.

[0066] The mass ratio of the organic solvent to the acid binding agent is 1:4, and the feed flow rate of benzene is 1.46 tons / hour.

[0067] The temperatures of the circulating kettle and the circulating flow reactor are both 50°C.

[0068] The circulation flow rate of the circulation pump is 4 tons / hour.

[0069] The feed flow rate of the methanol is 0.32 ton / hour, the feed flow rate of the phosphorus trichloride is 0.4 ton / hour, and the temperature of the water washing kettle is 20°C.

[0070] Comparative Example 2

[0071] The specific implementation of this comparative example is the same as that of Example 1, except that the second aspect of this comparative example provides a continuous production process of trimethyl phosphite, comprising the following steps:

[0072] S1. Pre-add 15 wt % sodium hydroxide solution into a water washing kettle, and the feed flow rate of the sodium hydroxide solution is 2.5 tons / hour.

[0073] S2, feeding the mixed solution of the organic solvent and the acid binding agent precooled by the precooler to the outlet of the circulation pump through a pipeline, and the feed flow rate of the mixed solution is 7.3 tons / hour;

[0074] S3, after the material level in the circulating kettle rises to 50% of the overall height of the circulating kettle, the circulating pump is turned on to form circulating materials;

[0075] S4, the methanol in the methanol tank is mixed with the mixed solution of S2 through a pipeline and then fed to the outlet of the circulation pump through a pipeline; at the same time, the phosphorus trichloride in the phosphorus trichloride tank is added perpendicularly to the circulating material at the inlet of the circulating flow reactor to react;

[0076] S5. After the liquid level in the circulating kettle rises to the overflow port, the material overflows into the water washing kettle and reacts with the alkaline solution in the water washing kettle. The reaction liquid passes through the stratification system and the distillation system in sequence through the pipeline to finally produce trimethyl phosphite.

[0077] In the step S2, the organic solvent is benzene and the acid binding agent is triethylamine.

[0078] The mass ratio of the organic solvent to the acid binding agent is 2.3:5, and the feed flow rate of benzene is 2.3 tons / hour.

[0079] The temperatures of the circulating kettle and the circulating flow reactor are both 62°C.

[0080] The circulation flow rate of the circulation pump is 4 tons / hour.

[0081] The feed flow rate of the methanol is 0.32 ton / hour, the feed flow rate of the phosphorus trichloride is 0.4 ton / hour, and the temperature of the water washing kettle is 10°C.

[0082] Comparative Example 3

[0083] The specific implementation method of this comparative example is the same as that of Example 1, except that Comparative Example 3 provides a continuous production process of trimethyl phosphite, comprising the following steps:

[0084] S1. Pre-add 15 wt % sodium hydroxide solution into a water washing kettle, and the feed flow rate of the sodium hydroxide solution is 2.5 tons / hour.

[0085] S2, feeding the mixed solution of the organic solvent and the acid binding agent precooled by the precooler to the outlet of the circulation pump through a pipeline, and the feed flow rate of the mixed solution is 7.3 tons / hour;

[0086] S3, after the material level in the circulating kettle rises to 50% of the overall height of the circulating kettle, the circulating pump is turned on to form circulating materials;

[0087] S4, the mixed solution of phosphorus trichloride, methanol and S2 enters the autoclave reactor in the same direction through the nozzle at the bottom of the autoclave for reaction;

[0088] S5. After the liquid level in the circulating kettle rises to the overflow port, the material overflows into the water washing kettle and reacts with the alkaline solution in the water washing kettle. The reaction liquid passes through the stratification system and the distillation system in sequence through the pipeline to finally produce trimethyl phosphite.

[0089] In the step S2, the organic solvent is benzene and the acid binding agent is triethylamine.

[0090] The mass ratio of the organic solvent to the acid binding agent is 1:4, and the feed flow rate of benzene is 1.46 tons / hour.

[0091] The temperatures of the circulating kettle and the circulating flow reactor were both 62°C.

[0092] The circulation flow rate of the circulation pump is 4 tons / hour.

[0093] The feed flow rate of the methanol is 0.32 ton / hour, the feed flow rate of the phosphorus trichloride is 0.4 ton / hour, and the temperature of the water washing kettle is 10°C.

[0094] Performance Testing

[0095] Example 1 and Comparative Examples 1-3 were tested, and the test data are listed in Table 1.

[0096] Calculation of trimethyl phosphite yield (mass ratio): trimethyl phosphite yield = (actual trimethyl phosphite output / theoretical trimethyl phosphite output) × 100%.

[0097] Content (mass ratio) test: using high performance liquid chromatography detection.

[0098] Table 1

[0099] Yield (%) content(%) Example 1 96.1 99.7 Comparative Example 1 92.2 98.3 Comparative Example 2 91.5 98.5 Comparative Example 3 94.0 99.3

Claims

1. A high-efficiency continuous production device for trimethyl phosphite, characterized in that: The device comprises a solvent tank, a precooler, a methanol tank, a circulation pump, a phosphorus trichloride tank, a circulation flow reactor, a circulation kettle, an alkali precooler, a water washing kettle, a stratification system and a distillation system; the solvent tank is connected with the precooler through a pipeline, the precooler, the methanol tank and the phosphorus trichloride tank are respectively connected with the circulation flow reactor through pipelines, the circulation kettle is connected with the circulation flow reactor in a closed loop through the circulation pump through pipelines, the alkali precooler is connected with the water washing kettle through pipelines, and the water washing kettle is connected with the distillation system through pipelines through the stratification system.

2. A high-efficiency continuous production process of trimethyl phosphite, characterized in that: The efficient continuous production process of trimethyl phosphite adopts the efficient continuous production device of trimethyl phosphite according to claim 1, and the efficient continuous production process of trimethyl phosphite comprises the following steps: S1, pre-adding alkaline solution into the washing kettle; S2, precooling the solvent in the solvent tank through a precooler and then feeding it to the outlet of the circulation pump through a pipeline; S3, after the material level in the circulating kettle rises to 50% of the overall height of the circulating kettle, the circulating pump is turned on to form circulating materials; S4, the methanol in the methanol tank is mixed with the solvent in S2 through a pipeline and then fed to the outlet of the circulation pump through a pipeline; at the same time, the phosphorus trichloride in the phosphorus trichloride tank is added perpendicularly to the circulating material at the inlet of the circulating flow reactor to react; S5. After the liquid level in the circulating kettle rises to the overflow port, the material overflows into the water washing kettle and reacts with the alkaline solution in the water washing kettle. The reaction liquid passes through the stratification system and the distillation system in sequence through the pipeline to finally produce trimethyl phosphite.

3. The efficient continuous production process of trimethyl phosphite according to claim 2, characterized in that: The feed flow rate of the alkaline solution in step S1 is 1.5-3.5 tons / hour.

4. The efficient continuous production process of trimethyl phosphite according to claim 2, characterized in that: In the step S2, the solvent comprises an organic solvent and an acid binding agent, and the mass ratio of the organic solvent to the acid binding agent is 1:(3-7).

5. The efficient continuous production process of trimethyl phosphite according to claim 4, characterized in that: The feed flow rate of the solvent in the step S2 is 5.4-10 tons / hour.

6. The efficient continuous production process of trimethyl phosphite according to claim 2, characterized in that: The temperature of the circulating kettle is controlled at 50-65°C.

7. The efficient and continuous production process of trimethyl phosphite according to claim 2, characterized in that: The temperature of the circulating flow reactor is controlled at 50-65°C.

8. The efficient and continuous production process of trimethyl phosphite according to claim 2, characterized in that: The circulation flow rate of the circulation pump is 3-5 tons / hour.

9. The efficient and continuous production process of trimethyl phosphite according to claim 2, characterized in that: The feed flow ratio of methanol and phosphorus trichloride is (2-4):(3-5).

10. The efficient and continuous production process of trimethyl phosphite according to claim 2, characterized in that: The temperature of the water washing kettle is controlled at 0-15°C.

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