Microchannel preparation method of triethyl phosphite
By using liquid ammonia as acid binding agent and solvent in the microchannel reactor, phosphorus trichloride and anhydrous ethanol as raw materials, the problems of large solvent usage and serious environmental pollution in the prior art were solved, and triethyl phosphite was realized efficient and low-cost production.
Patent Information
- Application Number
- CN202411424323.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2025-01-07
AI Technical Summary
The solvents used in the existing triethyl phosphite production methods such as dichloromethane, benzene and petroleum ether lead to high costs and serious environmental pollution, and acid-bound agents such as sodium ethylate are expensive, resulting in hazardous waste during the recycling process.
Using microchannel reactors, using phosphorus trichloride and anhydrous ethanol as raw materials, and liquid ammonia as acid binding agents and solvents, reacting through microchannel reactors at specific temperatures and pressures, reducing solvent usage, shortening reaction time, and improving production. rate and cost reduction.
It greatly reduces the amount of solvent and reaction time, reduces production costs, reduces environmental pollution, and improves the yield and purity of triethyl phosphite.
Smart Images
Figure CN119264181A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of organic synthesis, and in particular to a microchannel preparation method of triethyl phosphite. Background Art
[0002] Triethyl phosphite is an organic reagent widely used in the fields of medicine and pesticides. It can also be used as a plasticizer and stabilizer for plastics and an additive and stabilizer for lubricants. In recent years, as the global requirements for safety and environmental protection have become increasingly stringent, phosphorus-based halogen-free flame retardant products using triethyl phosphite as raw material have been greatly developed.
[0003] At present, the production of triethyl phosphite mostly adopts the batch process in a kettle, all of which use ethanol and phosphorus trichloride as raw materials, with different acid-binding agents and solvents. The main solvents are dichloromethane, benzene, petroleum ether, etc. Among them, solvents such as dichloromethane and petroleum ether have low boiling points. Although they are easy to separate from the product, they are lost in production, resulting in excessive costs. Benzene solvents are highly toxic and cause serious environmental pollution. The main acid-binding agents are sodium ethoxide, triethylamine, dimethylaniline, liquid ammonia, etc. Among them, sodium ethoxide is expensive and not very economical. A large amount of phosphorus-containing hazardous waste will be generated during the recovery process of triethylamine and dimethylaniline, causing serious environmental pollution. Liquid ammonia is cheap and can dissolve the ammonium salts generated during the preparation process, reducing the use of organic solvents. The ammonium chloride generated can be used as an agricultural fertilizer, which is beneficial to reduce costs. Summary of the invention In order to solve the deficiencies in the prior art, the present invention provides a microchannel preparation method for triethyl phosphite, using phosphorus trichloride and ethanol as raw materials, and liquid ammonia as a solvent and an acid-binding agent. The method is simple to operate, greatly reduces the amount of solvent used, greatly shortens the reaction time, has low cost, and causes little environmental pollution. The scheme adopted by the present invention to achieve the purpose is: in the method, phosphorus trichloride and anhydrous ethanol are used as raw materials, and liquid ammonia is used as an acid-binding agent and a solvent in a microchannel reactor, and a crude product is obtained at a certain reaction temperature and pressure after a certain reaction time. The crude product is purified to obtain triethyl phosphite. The method is simple to operate, greatly shortens the reaction time, has high production capacity, high yield, low cost, and little environmental pollution. The microchannel reactor used in the present invention is selected from Corning G1 glass reactor.
[0004] In view of the above technical features, the present invention provides a microchannel preparation method of triethyl phosphite, wherein liquid ammonia and ethanol are cooled through a coil and then mixed evenly to obtain a liquid ammonia-ethanol mixed liquid; The liquid ammonia and ethanol mixed liquid and phosphorus trichloride are simultaneously pumped into the plate of the microchannel reactor to react, the effluent is collected, and the ammonium chloride is removed by centrifugation to obtain a reaction mother liquor, and the reaction mother liquor is reduced in pressure, heated, and rectified to obtain high-purity triethyl phosphite.
[0005] Preferably, the mass of the liquid ammonia is 5-20 times that of ethanol, and more preferably, the mass of the liquid ammonia is 10-20 times that of ethanol.
[0006] Preferably, the raw materials are cooled to -50~0°C before mixing and reacting, and more preferably, the raw materials are cooled to -50~-35°C before mixing and reacting.
[0007] Preferably, the molar ratio of phosphorus trichloride to ethanol is 1:3.01-5.00.
[0008] Preferably, the temperature of the microchannel reactor is -50~0°C, more preferably the temperature of the microchannel reactor is -50~-10°C, more preferably the temperature of the microchannel reactor is -50~-20°C, and more preferably the temperature of the microchannel reactor is -50~-35°C.
[0009] Preferably, the microchannel reactor has a volume of 8-32 mL and a residence time of 0.5-10 s.
[0010] The reaction mother liquor replaces liquid ammonia and is continuously introduced into the microchannel reactor after being cooled to -50-0°C. After the reaction mother liquor is applied to the microchannel reaction, the concentration of triethyl phosphite therein reaches 5-60%, that is, the concentration of triethyl phosphite is applied and achieved to reach any value between 5% and 60%.
[0011] In some preferred schemes, the reaction mother liquor replaces liquid ammonia and is continuously introduced into the microchannel reactor after being cooled to -50~-35°C. After the reaction mother liquor is applied to the microchannel reaction, the concentration of triethyl phosphite therein reaches 8~50%.
[0012] Preferably, the liquid ammonia in the reaction system is removed by reducing pressure and raising temperature, and the temperature is 20-50° C. and the pressure is 100-300 mbar.
[0013] Preferably, the distillation tower has a temperature of 120-130°C and a pressure of 8-10 KPa.
[0014] The present invention has the following advantages and beneficial effects: The solvents used in the production of triethyl phosphite mainly include dichloromethane, benzene, petroleum ether, etc. These solvents have poor solubility for the solid salts produced in the reaction. In order to make the reaction proceed normally, a large amount of solvents need to be used, and the energy consumption of solvent recovery and reuse is large, and the cost is high. The method uses liquid ammonia as an acid binding agent and solvent. Liquid ammonia has good solubility for ammonium chloride produced by the reaction. Compared with the existing technology, the amount of solvent used is greatly reduced, the energy consumption is reduced, and the reaction mother liquor can be continuously reused, which effectively reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION
[0016] For a better understanding of the present invention, the following examples are provided to further illustrate the present invention, but the present invention is not limited to the following examples.
[0017] Embodiment 1: Liquid ammonia and ethanol were cooled to -40°C through a coil and then uniformly mixed in a mass ratio of 10:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.8% and the yield was 99.5%.
[0018] Embodiment 2: Liquid ammonia and ethanol were cooled to -40°C through a coil and then uniformly mixed in a mass ratio of 8:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.6% and the yield was 97.6%.
[0019] Embodiment 3: Liquid ammonia and ethanol were cooled to -40°C through a coil and then uniformly mixed in a mass ratio of 5:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.6% and the yield was 96.3%.
[0020] Embodiment 4: Liquid ammonia and ethanol were cooled to -30°C through a coil and then uniformly mixed in a mass ratio of 10:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.8% and the yield was 97.3%.
[0021] Embodiment 5: Liquid ammonia and ethanol were cooled to -20°C through a coil and then uniformly mixed in a mass ratio of 10:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and the ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.7% and the yield was 95.2%.
[0022] Embodiment 6: Liquid ammonia and ethanol are cooled to -40°C through a coil and then mixed evenly in a mass ratio of 10:1 to obtain a liquid ammonia-ethanol mixed liquid, which is then pumped into the plate of a microchannel reactor at a molar ratio of 1:3.01 with phosphorus trichloride to ethanol for reaction. The temperature of the microchannel reactor is -35°C, the residence time is 0.8 s, the effluent is collected, and the ammonium chloride is removed by centrifugation to obtain a reaction mother liquor. The reaction mother liquor replaces liquid ammonia and is cooled to -40°C and then continues to enter the microchannel reactor to react with phosphorus trichloride. The mother liquor is applied to the mother liquor until the content of triethyl phosphite reaches 5-60%, as shown in the following table. The liquid ammonia in the reaction system is removed by reducing pressure and heating, and the evaporated ammonia gas is collected and reused by a compressor, and distilled to obtain high-purity triethyl phosphite. The absolute concentration of triethyl phosphite is calibrated by gas chromatography, and the conversion rate is calculated.
[0023] Number of applications 1 2 3 4 5 6 7 8 9 Triethyl phosphite concentration 8.62% 16.53% 24.32% 33.56% 42.63% 49.66% 52.36% 57.63% 61.22% Conversion rate 99.50% 99.02% 98.82% 98.55% 98.01% 97.53% 92.10% 85.32% 76.30% Comparative Example 1: Liquid ammonia and ethanol were cooled to -40°C through a coil and then uniformly mixed in a mass ratio of 4:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and the ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.5% and the yield was 76.3%.
[0024] Comparative Example 2: Liquid ammonia and ethanol were cooled to -40°C through a coil and then uniformly mixed in a mass ratio of 25:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.6% and the yield was 92.1%.
[0025] Comparative Example 3: Liquid ammonia and ethanol were cooled to 0°C through a coil and then uniformly mixed in a mass ratio of 10:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.4% and the yield was 86.7%.
[0026] Comparative Example 4: Liquid ammonia and ethanol were cooled to 10°C through a coil and then uniformly mixed in a mass ratio of 10:1 to obtain a liquid ammonia-ethanol mixed liquid, which was then simultaneously pumped into a plate of a microchannel reactor with phosphorus trichloride in a molar ratio of 1:3.01 to ethanol for reaction. The temperature of the microchannel reactor was -35°C, the residence time was 0.8 s, the effluent was collected, and the liquid ammonia in the reaction system was removed by distillation at 200 mbar and 50°C. The evaporated ammonia gas was collected and reused by a compressor, and ammonium chloride was removed by centrifugation. After rectification and sampling, the product content was 99.3% and the yield was 72.5%.
Claims
1. A microchannel preparation method for triethyl phosphite, characterized in that: Liquid ammonia and ethanol are cooled through a coil and then mixed evenly to obtain a liquid ammonia-ethanol mixed liquid; The liquid ammonia and ethanol mixed liquid and phosphorus trichloride are simultaneously pumped into the plate of the microchannel reactor to react, the effluent is collected, and the ammonium chloride is removed by centrifugation to obtain a reaction mother liquor, and the reaction mother liquor is reduced in pressure, heated, and rectified to obtain high-purity triethyl phosphite.
2. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: In the liquid ammonia and ethanol mixed liquid, the mass of liquid ammonia is 5 to 20 times that of ethanol.
3. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: The raw materials are cooled to -50~0°C before mixing and reacting.
4. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: The molar ratio of phosphorus trichloride to ethanol is 1:3.01-5.
00.
5. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: The temperature of the microchannel reactor is -50~0°C.
6. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: The volume of the microchannel reactor is 8-32 mL, and the residence time is 0.5-10 s.
7. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: The reaction mother liquor replaces liquid ammonia and is continuously introduced into the microchannel reactor for application after being cooled to -50-0°C. After the reaction mother liquor is applied to the microchannel reaction, the concentration of triethyl phosphite therein reaches 5-60%.
8. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: The reduced pressure and increased temperature are used to remove liquid ammonia in the reaction system at a temperature of 20-50° C. and a pressure of 100-300 mbar.
9. The microchannel preparation method of triethyl phosphite according to claim 1, characterized in that: The distillation tower has a temperature of 120-130°C and a pressure of 8-10KPa.