Continuous production process and device for dimethyl phosphite
By using a circulating flow reactor and microdistributor in the synthesis process of dimethyl phosphite, the problems of severe reaction and low production efficiency in the prior art are solved, and a more efficient, safe and environmentally friendly dimethyl phosphite production is achieved.
Patent Information
- Application Number
- CN202510036669.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-09
- Publication Date
- 2025-04-15
AI Technical Summary
The existing synthesis method of dimethyl phosphite has problems such as severe reaction, large heat exogenous, high equipment requirements and low production efficiency. The traditional kettle reaction has problems such as poor jacket heat exchange effect and poor separation of hydrogen chloride and chloromethane.
Using a circulating flow reactor, phosphorus trichloride is added at the inlet of the circulating flow reactor in proportion, and it reacts rapidly with methanol through a microdistributor to produce dimethyl phosphite. Through the design of the circulation pump and microdistributor, this process achieves full contact of reactants and effective removal of reaction heat, improving the safety and efficiency of reaction.
This process effectively improves the production efficiency and product quality of dimethyl phosphite, reduces production costs and environmental impacts, enhances operational safety and raw material utilization, and achieves a more environmentally friendly, economical and sustainable production method.
Smart Images
Figure CN119819220A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of organic raw materials, and in particular to a continuous production process and device for dimethyl phosphite. Background Art
[0002] Dimethyl phosphite is widely used in the production of herbicide glyphosate, insecticides dichlorvos, trichlorfon, omethoate, flame retardants for textiles, antioxidants and other chemical products.
[0003] At present, there are two main methods for the synthesis of dimethyl phosphite. One method is to directly synthesize dimethyl phosphite using phosphorous acid and methanol as raw materials. However, this method requires efficient catalyst catalytic conditions to react, and the reaction conversion rate is low, making it difficult to achieve industrialization. The other method is also the current mainstream synthesis method, which mainly uses phosphorus trichloride and methanol as raw materials to esterify dimethyl phosphite. However, this method has a violent reaction, a large amount of heat release, and high requirements on the vacuum degree and mass transfer and heat transfer performance of the equipment, and is usually mainly based on a kettle reaction.
[0004] In "Research on the Synthesis of Dimethyl Phosphite in Continuous Flow Microreactor, Liu Jianwu et al., Chem.World, 2021, 62(8), 492-497", the study shows that microchannel reactors have the characteristics of strong mass transfer and heat transfer, which solves the inherent safety problems caused by the violent reaction and large heat release of traditional reactors. Patent publication number CN115282873B discloses a dimethyl phosphite synthesis device and process, which sets the traditional counter-feed pipe inside the reactor and sets up a multi-stage condensed methanol reflux. In essence, the reaction is still a kettle reaction, and the reflux process is relatively complicated.
[0005] The traditional kettle type has a large production capacity, but the jacket heat exchange effect is poor, which affects the separation effect of hydrogen chloride and methyl chloride. In contrast, the microchannel reactor has better mass transfer and heat transfer effects, but the equipment cost is high and the production capacity is limited. It can only be used for small batch production, which limits its application in large-scale production. Summary of the invention
[0006] Problem that the invention aims to solve
[0007] In order to solve the above problems, the present invention provides a continuous production process and device for dimethyl phosphite, which adopts a circulating flow reactor, phosphorus trichloride is added at the inlet of the circulating flow reactor in proportion, and reacts quickly with methanol through a micro-distributor, which can effectively improve the production efficiency and control the reaction in a milder manner.
[0008] Solutions for solving problems
[0009] In order to solve the above technical problems, the present invention provides a continuous production process of dimethyl phosphite, comprising the following steps:
[0010] (1) Adding bottom material into the primary deacidification kettle;
[0011] (2) The bottom of the primary deacidification reactor is connected to the inlet of a circulation pump, methanol is fed to the circulation flow reactor at the outlet of the circulation pump, and phosphorus trichloride is fed to the circulation flow reactor at the inlet of the circulation flow reactor;
[0012] (3) The reaction product generated in step (2) enters the primary deacidification kettle and the secondary deacidification kettle in sequence;
[0013] (4) obtaining dimethyl phosphite after two-stage deacidification;
[0014] Wherein, in step (1), the base material is methanol and / or crude dimethyl phosphite.
[0015] Preferably, in step (1), the crude dimethyl phosphite has a dimethyl phosphite content of ≥88% and a free acid content of ≤6%.
[0016] Preferably, in step (1), the methanol content is 95-100%, preferably 97-99%.
[0017] Preferably, in step (2), the material temperature in the circulating flow reactor is controlled to be 15-30°C, preferably 20-30°C, more preferably 25-30°C.
[0018] Preferably, the circulation flow rate of the circulation pump is controlled to be 1-2.2 tons / hour.
[0019] Preferably, the mass flow rate of the methanol is controlled to be 0.8-2 tons / hour.
[0020] Preferably, the mass flow rate of the phosphorus trichloride is controlled to be 0.6-1.4 tons / hour.
[0021] Preferably, the mass ratio of the phosphorus trichloride to the methanol is (0.70-0.85):1, preferably (0.70-0.80):1, and more preferably (0.70-0.75):1.
[0022] Preferably, in the step (3), the first-stage deacidification kettle and the second-stage deacidification kettle are discharged in an overflow form.
[0023] Preferably, the controlled temperature of the primary deacidification kettle is 30-45°C, preferably 30-40°C.
[0024] Preferably, the controlled temperature of the secondary deacidification kettle is 65-85°C, preferably 70-85°C, more preferably 75-80°C.
[0025] Preferably, the pressure of the circulating flow reactor, the primary deacidification kettle and the secondary deacidification kettle is -100 kPa to -90 kPa, preferably -98 kPa to -92 kPa, and more preferably -98 kPa to -95 kPa.
[0026] Preferably, the circulating flow reactor, the primary deacidification kettle, and the secondary deacidification kettle have the same pressure.
[0027] Preferably, in the step (3), the product of the secondary deacidification reactor can be used as the bottom material in the step (1).
[0028] Preferably, the process further comprises: before step (1), vacuuming the production system.
[0029] Preferably, the system is evacuated to a vacuum pressure of -100 kPa to -90 kPa.
[0030] Preferably, the process further comprises: condensing and refluxing the gas phase of the first-stage deacidification kettle.
[0031] Preferably, the process further comprises: condensing and refluxing the gas phase of the secondary deacidification kettle.
[0032] Preferably, the process further comprises: the methanol feed direction enters the circulating flow reactor in parallel with the circulating flow.
[0033] Preferably, the process further comprises: feeding the phosphorus trichloride into the circulating flow reactor in a feeding direction at the inlet of the circulating flow reactor perpendicular to the circulating flow.
[0034] Preferably, the process further comprises: the phosphorus trichloride is injected into the circulating flow reactor through injection holes of a micro-distributor in the circulating flow reactor in a feeding direction perpendicular to the circulating flow at the inlet of the circulating flow reactor.
[0035] The present invention also provides a continuous production device for dimethyl phosphite, comprising a phosphorus trichloride feed port and a methanol feed port, both of which are connected to a circulating flow reactor respectively;
[0036] After the circulating flow reactor, a primary deacidification kettle, a secondary deacidification kettle and a crude ester tank are arranged in sequence;
[0037] The bottom of the first-stage deacidification reactor is connected to a circulation pump, and the circulating flow reactor is externally connected to a circulation pump;
[0038] A micro-distributor is arranged in the circulating flow reactor.
[0039] Preferably, injection holes are arranged on the upper side of the micro-distributor.
[0040] Preferably, the phosphorus trichloride feed port is connected to the material feed port of the micro-distributor.
[0041] Preferably, the opening direction of the injection hole is consistent with the circulation flow direction.
[0042] Preferably, the feeding direction of the material feed port is perpendicular to the circulation flow direction.
[0043] Preferably, the feeding direction of the methanol feed port is consistent with the circulating flow direction.
[0044] Preferably, the circulating flow reactor has a jacket heat exchange structure.
[0045] Preferably, the first-stage deacidification kettle is provided with an overflow port, and the overflow port is connected to the second-stage deacidification kettle through a pipeline.
[0046] Preferably, the secondary deacidification kettle is provided with an overflow port, and the overflow port is connected to the crude ester tank through a pipeline.
[0047] Preferably, the bottom of the secondary deacidification kettle is connected to the crude ester tank through a pipeline.
[0048] Preferably, the first-stage deacidification kettle and the second-stage deacidification kettle are both provided with gas phase outlets, and the gas phase outlets are connected to the first-stage condensation trap and the second-stage condensation trap through pipelines.
[0049] Preferably, the condensate from the first-stage condensation collector connected to the gas phase outlet of the first-stage deacidification kettle flows back to the first-stage deacidification kettle, and the condensate from the second-stage condensation collector connected to the gas phase outlet of the second-stage deacidification kettle flows back to the second-stage deacidification kettle.
[0050] Preferably, the phosphorus trichloride feed port and the methanol feed port are both provided with flow regulating valves.
[0051] Preferably, the circulating flow reactor, the primary deacidification kettle, and the secondary deacidification kettle are all provided with a temperature controller.
[0052] Preferably, the gas phase outlets of the primary condensation trap and the secondary condensation trap are connected to a tail gas recovery device.
[0053] Effects of the Invention
[0054] The present invention creates conditions for phosphorus trichloride and methanol to fully contact, shortens the reaction time, effectively removes the reaction heat, removes hydrogen chloride in the reaction product as much as possible, and inhibits the occurrence of side reactions; the system is kept running under high vacuum conditions, and the HCl gas generated by the reaction is promptly removed from the reaction system, thereby improving the selectivity of dimethyl phosphite. By optimizing the process flow and equipment design, the production efficiency and product quality are improved, the production cost and environmental impact are reduced, and the safety of operation and the utilization rate of raw materials are enhanced, achieving a more environmentally friendly, economical and sustainable production method, which is suitable for large-scale production. The dimethyl phosphite finally obtained meets the following requirements: dimethyl phosphite content ≥ 92%, free acid ≤ 4%. BRIEF DESCRIPTION OF THE DRAWINGS
[0055] Figure 1 The present invention is a process flow chart for preparing dimethyl phosphite.
[0056] Figure 2 Schematic diagram of the micro-distributor of the circulating flow reactor used in the present invention.
[0057] Description of reference numerals:
[0058] 1-phosphorus trichloride feed port, 2-methanol feed port, 3-circulating flow reactor, 31-micro distributor, 32-injection hole, 33-material feed port, 4-first-stage deacidification kettle, 41-first-stage condensation collector, 5-second-stage deacidification kettle, 51-second-stage condensation collector, 6-crude ester tank, 7-circulation pump. DETAILED DESCRIPTION
[0059] In order to make the technical solutions and beneficial effects of the present invention more clearly understandable, the following is a detailed description by listing specific embodiments. The drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.
[0060] The present invention provides a continuous production process of dimethyl phosphite, comprising the following steps:
[0061] (1) Adding bottom material into the primary deacidification kettle;
[0062] (2) The bottom of the primary deacidification reactor is connected to the inlet of a circulation pump, methanol is fed to the circulation flow reactor at the outlet of the circulation pump, and phosphorus trichloride is fed to the circulation flow reactor at the inlet of the circulation flow reactor;
[0063] (3) The reaction product generated in step (2) enters the primary deacidification kettle and the secondary deacidification kettle in sequence;
[0064] (4) obtaining dimethyl phosphite after two-stage deacidification;
[0065] Wherein, in step (1), the base material is methanol and / or crude dimethyl phosphite.
[0066] In certain embodiments, in step (1), the crude dimethyl phosphite has a dimethyl phosphite content of ≥88% and a free acid content of ≤6%.
[0067] In certain embodiments, in step (1), the methanol content is 95-100%.
[0068] In certain embodiments, in step (1), the methanol content is 97-99%.
[0069] In certain embodiments, in step (2), the material temperature in the circulating flow reactor is controlled to be 15-30°C.
[0070] In certain embodiments, in step (2), the material temperature in the circulating flow reactor is controlled to be 20-30°C.
[0071] In certain embodiments, in step (2), the material temperature in the circulating flow reactor is controlled to be 25-30°C.
[0072] In certain embodiments, the circulation flow rate of the circulation pump is controlled to be 1-2.2 tons / hour.
[0073] In certain embodiments, the mass flow rate of methanol is controlled to be 0.8-2 tons / hour.
[0074] In certain embodiments, the mass flow rate of phosphorus trichloride is controlled to be 0.6-1.4 tons / hour.
[0075] In certain embodiments, the mass ratio of the phosphorus trichloride to the methanol is (0.70-0.85):1, for example, 0.70:1, 0.71:1, 0.72:1, 0.73:1, 0.74:1, 0.75:1, 0.76:1, 0.77:1, 0.78:1, 0.79:1, 0.80:1, 0.81:1, 0.82:1, 0.83:1, 0.84:1, 0.85:1, etc.
[0076] In certain embodiments, the mass ratio of the phosphorus trichloride to the methanol is (0.70-0.80):1.
[0077] In certain embodiments, the mass ratio of the phosphorus trichloride to the methanol is (0.70-0.75):1.
[0078] In certain embodiments, in step (3), the first deacidification kettle and the second deacidification kettle are discharged in an overflow form.
[0079] In certain embodiments, the controlled temperature of the primary deacidification kettle is 30-45°C, for example, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, etc.
[0080] In certain embodiments, the controlled temperature of the primary deacidification reactor is 30-40°C.
[0081] In certain embodiments, the controlled temperature of the secondary deacidification kettle is 65-85°C, for example, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, etc.
[0082] In certain embodiments, the controlled temperature of the secondary deacidification kettle is 70-85°C.
[0083] In certain embodiments, the controlled temperature of the secondary deacidification kettle is 75-80°C.
[0084] In certain embodiments, the pressure of the circulating flow reactor, the primary deacidification kettle, and the secondary deacidification kettle is -100 kPa to -90 kPa, for example, -90 kPa, -91 kPa, -92 kPa, -93 kPa, -94 kPa, -95 kPa, -96 kPa, -97 kPa, -98 kPa, -99 kPa, -100 kPa, etc.
[0085] In certain embodiments, the pressure of the circulating flow reactor, the primary deacidification kettle, and the secondary deacidification kettle is -98 kPa to -92 kPa.
[0086] In certain embodiments, the pressure of the circulating flow reactor, the primary deacidification kettle, and the secondary deacidification kettle is -98 kPa to -95 kPa.
[0087] In certain embodiments, the circulating flow reactor, the primary deacidification reactor, and the secondary deacidification reactor are at the same pressure.
[0088] In certain embodiments, in step (3), the product of the secondary deacidification reactor can be used as the bottom material in step (1).
[0089] In certain embodiments, the process further comprises: before step (1), vacuuming the production system.
[0090] In certain embodiments, the system is vacuumed to a pressure of -100 kPa to -90 kPa, for example, -90 kPa, -91 kPa, -92 kPa, -93 kPa, -94 kPa, -95 kPa, -96 kPa, -97 kPa, -98 kPa, -99 kPa, -100 kPa, etc.
[0091] In certain embodiments, the process further comprises: condensing and refluxing the gas phase of the first-stage deacidification reactor.
[0092] In certain embodiments, the process further comprises: condensing and refluxing the gas phase of the secondary deacidification reactor.
[0093] In certain embodiments, the process further comprises: the methanol feed direction enters the circulating flow reactor in parallel with the circulating flow.
[0094] In certain embodiments, the process further comprises: feeding the phosphorus trichloride into the circulating flow reactor in a feeding direction at the inlet of the circulating flow reactor perpendicular to the circulating flow.
[0095] In certain embodiments, the process further comprises: injecting the phosphorus trichloride into the circulating flow reactor through injection holes of a micro-distributor in the circulating flow reactor in a feeding direction perpendicular to the circulating flow at the inlet of the circulating flow reactor.
[0096] The present invention also provides a continuous production device for dimethyl phosphite, comprising a phosphorus trichloride feed port 1 and a methanol feed port 2, both of which are connected to a circulating flow reactor 3 respectively;
[0097] After the circulating flow reactor 3, a primary deacidification kettle 4, a secondary deacidification kettle 5, and a crude ester tank 6 are arranged in sequence;
[0098] The bottom of the first-stage deacidification kettle 4 is connected to a circulation pump 7, and the circulating flow reactor 3 is externally connected to the circulation pump 7;
[0099] A micro-distributor 31 is arranged in the circulating flow reactor 3 .
[0100] In some embodiments, the micro-distributor 31 is provided with injection holes 32 on its upper side.
[0101] In some embodiments, the phosphorus trichloride feed port 1 is connected to the material feed port 33 of the micro-distributor 31 .
[0102] In some embodiments, the opening direction of the injection hole 32 is consistent with the circulation flow direction.
[0103] In certain embodiments, the feeding direction of the material feed port 33 is perpendicular to the circulation flow direction.
[0104] In certain embodiments, the feeding direction of the methanol feed port 2 is consistent with the circulating flow direction.
[0105] In certain embodiments, the circulating flow reactor 3 has a jacket heat exchange structure.
[0106] In some embodiments, the primary deacidification kettle 4 is provided with an overflow port, and the overflow port is connected to the secondary deacidification kettle 5 through a pipeline.
[0107] In some embodiments, the secondary deacidification kettle 5 is provided with an overflow port, and the overflow port is connected to the crude ester tank 6 through a pipeline.
[0108] In certain embodiments, the bottom of the secondary deacidification kettle 5 is connected to the crude ester tank 6 via a pipeline.
[0109] In certain embodiments, the primary deacidification kettle 4 and the secondary deacidification kettle 5 are both provided with gas phase outlets, and the gas phase outlets are connected to the primary condensation trap 41 and the secondary condensation trap 51 through pipelines.
[0110] In certain embodiments, the condensate from the first-level condensation collector 41 connected to the gas phase outlet of the first-level deacidification kettle 4 is refluxed to the first-level deacidification kettle 4, and the condensate from the second-level condensation collector 51 connected to the gas phase outlet of the second-level deacidification kettle 5 is refluxed to the second-level deacidification kettle 5.
[0111] In certain embodiments, the phosphorus trichloride feed port 1 and the methanol feed port 2 are both provided with flow regulating valves.
[0112] In certain embodiments, the circulating flow reactor 3, the primary deacidification kettle 4, and the secondary deacidification kettle 5 are all provided with temperature controllers.
[0113] In certain embodiments, gas phase outlets of the primary condensation trap 41 and the secondary condensation trap 51 are connected to a tail gas recovery device.
[0114] In this article, "circulating flow" refers to the phenomenon in which all or part of the fluid in a flow system is allowed to circulate along a certain direction and path.
[0115] The method of the present invention is described below by means of specific examples. It should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in routine experiments.
[0116] Example 1
[0117] Add 1 ton of crude dimethyl phosphite (dimethyl phosphite content ≥ 88%, free acid ≤ 6%) into the first-stage deacidification kettle, control the temperature of the first-stage deacidification kettle at 30°C, start the circulation pump, and the circulation flow rate is 1.1 tons / hour; methanol is added at the outlet of the circulation pump, and the feed flow rate is 1 ton / hour; phosphorus trichloride enters horizontally at the inlet of the circulating flow reactor, and the feed flow rate is 0.7 tons / hour; control the temperature of the material in the circulating flow reactor at 25°C; after the material reaches the overflow port of the first-stage deacidification kettle, it overflows to the second-stage deacidification kettle, and the temperature of the second-stage deacidification kettle is 75°C; after the material reaches the overflow port of the second-stage deacidification kettle, it overflows into the crude ester tank. The system vacuum degree is controlled at -95kpa. The material in the crude ester tank is analyzed and tested, and the free acid of crude dimethyl phosphite is 3.5%, and the content of dimethyl phosphite is 93.7%.
[0118] Example 2
[0119] Add 1 ton of methanol (methanol content = 99%) to the first-stage deacidification kettle, control the temperature of the first-stage deacidification kettle to 40°C, start the circulation pump circulation, the circulation flow rate is 1 ton / hour; methanol is added at the outlet of the circulation pump, the feed flow rate is 0.8 tons / hour; phosphorus trichloride enters horizontally at the inlet of the circulating flow reactor, the feed flow rate is 0.6 tons / hour; control the temperature of the material in the circulating flow reactor to 30°C; after the material reaches the overflow port of the first-stage deacidification kettle, it overflows to the second-stage deacidification kettle, the temperature of the second-stage deacidification kettle is 80°C; after the material reaches the overflow port of the second-stage deacidification kettle, it overflows into the crude ester tank. The system vacuum degree is controlled at -96kpa. The material in the crude ester tank is analyzed and tested, the crude dimethyl phosphite free acid is 3.3%, and the dimethyl phosphite content is 93.8%.
[0120] Comparative Example 1
[0121] Add 1 ton of crude dimethyl phosphite (dimethyl phosphite content ≥ 88%, free acid ≤ 6%) into the first-stage deacidification kettle, control the temperature of the first-stage deacidification kettle to 50°C, start the circulation pump, and the circulation flow rate is 1.1 tons / hour; methanol is added at the outlet of the circulation pump, and the feed flow rate is 1 ton / hour; phosphorus trichloride enters horizontally at the inlet of the circulating flow reactor, and the feed flow rate is 0.7 tons / hour; control the temperature of the material in the circulating flow reactor to 35°C; after the material reaches the overflow port of the first-stage deacidification kettle, it overflows to the second-stage deacidification kettle, and the temperature of the second-stage deacidification kettle is 75°C; after the material reaches the overflow port of the second-stage deacidification kettle, it overflows into the crude ester tank. The system vacuum degree is controlled at -95kpa. The material in the crude ester tank is analyzed and tested, and the free acid of crude dimethyl phosphite is 3.2%, and the content of dimethyl phosphite is 82.1%.
[0122] Comparative Example 2
[0123] Add 1 ton of crude dimethyl phosphite (dimethyl phosphite content ≥ 88%, free acid ≤ 6%) into the first-stage deacidification kettle, control the temperature of the first-stage deacidification kettle at 30°C, start the circulation pump, and the circulation flow rate is 1.1 tons / hour; methanol is added at the outlet of the circulation pump, and the feed flow rate is 1 ton / hour; phosphorus trichloride enters horizontally at the inlet of the circulating flow reactor, and the feed flow rate is 0.7 tons / hour; control the temperature of the material in the circulating flow reactor at 25°C; after the material reaches the overflow port of the first-stage deacidification kettle, it overflows to the second-stage deacidification kettle, and the temperature of the second-stage deacidification kettle is 75°C; after the material reaches the overflow port of the second-stage deacidification kettle, it overflows into the crude ester tank. The system vacuum degree is controlled at -85kpa. The material in the crude ester tank is analyzed and tested, and the free acid of crude dimethyl phosphite is 5.1%, and the content of dimethyl phosphite is 80.3%.
[0124] Comparative Example 3
[0125] Add 1 ton of crude dimethyl phosphite (dimethyl phosphite content ≥ 88%, free acid ≤ 6%) into the primary deacidification kettle, control the temperature of the primary deacidification kettle to 50°C, start the circulation pump, and the circulation flow rate is 1.1 tons / hour; methanol is added at the outlet of the circulation pump, and the feed flow rate is 1 ton / hour; phosphorus trichloride enters horizontally at the inlet of the circulating flow reactor (the circulating flow reactor has no micro-distributor), and the feed flow rate is 0.7 tons / hour; control the material temperature in the circulating flow reactor to 25°C; after the material reaches the overflow port of the primary deacidification kettle, it overflows to the secondary deacidification kettle, and the temperature of the secondary deacidification kettle is 75°C; after the material reaches the overflow port of the secondary deacidification kettle, it overflows into the crude ester tank. The system vacuum degree is controlled at -95kpa. The material in the crude ester tank is analyzed and tested, and the free acid of crude dimethyl phosphite is 4.8%, and the content of dimethyl phosphite is 87.5%.
[0126] It should be understood that the above embodiments are exemplary and are not intended to include all possible implementations included in the claims. Various modifications and changes may be made on the basis of the above embodiments without departing from the scope of the present disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only express several implementations of the present invention and do not limit the scope of protection of the patent of the present invention.
Claims
1. A continuous production process for dimethyl phosphite, characterized in that: The following steps are involved: (1) Adding bottom material into the primary deacidification kettle; (2) The bottom of the primary deacidification reactor is connected to the inlet of a circulation pump, methanol is fed to the circulation flow reactor at the outlet of the circulation pump, and phosphorus trichloride is fed to the circulation flow reactor at the inlet of the circulation flow reactor; (3) The reaction product generated in step (2) enters the primary deacidification kettle and the secondary deacidification kettle in sequence; (4) obtaining dimethyl phosphite after two-stage deacidification; Wherein, in step (1), the base material is methanol and / or crude dimethyl phosphite.
2. The continuous production process according to claim 1, characterized in that: In the step (1), the crude dimethyl phosphite has a dimethyl phosphite content of ≥88% and a free acid content of ≤6%; Preferably, in step (1), the methanol content is 95-100%, preferably 97-99%.
3. The continuous production process according to claim 1, characterized in that: In the step (2), the material temperature in the circulating flow reactor is controlled to be 15-30°C, preferably 20-30°C, more preferably 25-30°C; Preferably, the circulation flow rate of the circulation pump is controlled to be 1-2.2 tons / hour; Preferably, the mass flow rate of the methanol is controlled to be 0.8-2 tons / hour; Preferably, the mass flow rate of the phosphorus trichloride is controlled to be 0.6-1.4 tons / hour; Preferably, the mass ratio of the phosphorus trichloride to the methanol is (0.70-0.85):1, preferably (0.70-0.80):1, and more preferably (0.70-0.75):
1.
4. The continuous production process according to claim 1, characterized in that: In the step (3), the first-stage deacidification kettle and the second-stage deacidification kettle discharge materials in the form of overflow.
5. The continuous production process according to claim 1, characterized in that: The controlled temperature of the primary deacidification kettle is 30-45°C, preferably 30-40°C; Preferably, the controlled temperature of the secondary deacidification kettle is 65-85°C, preferably 70-85°C, more preferably 75-80°C.
6. The continuous production process according to claim 1, characterized in that: The pressure of the circulating flow reactor, the primary deacidification kettle, and the secondary deacidification kettle is -100 kPa to -90 kPa, preferably -98 kPa to -92 kPa, and more preferably -98 kPa to -95 kPa; Preferably, the circulating flow reactor, the primary deacidification kettle, and the secondary deacidification kettle have the same pressure.
7. The continuous production process according to claim 1, characterized in that: In the step (3), the product of the secondary deacidification reactor can be used as the bottom material in the step (1).
8. The continuous production process according to claim 1, characterized in that: The process further comprises: before step (1), vacuuming the production system; Preferably, the system is vacuumed to a pressure of -100 kPa to -90 kPa; Preferably, the process further comprises: condensing and refluxing the gas phase of the first-stage deacidification kettle; Preferably, the process further comprises: condensing and refluxing the gas phase of the secondary deacidification kettle; Preferably, the process further comprises: the methanol feed direction enters the circulating flow reactor in parallel with the circulating flow; Preferably, the process further comprises: feeding the phosphorus trichloride into the circulating flow reactor in a feeding direction perpendicular to the circulating flow at the inlet of the circulating flow reactor; Preferably, the process further comprises: the phosphorus trichloride is injected into the circulating flow reactor through injection holes of a micro-distributor in the circulating flow reactor in a feeding direction perpendicular to the circulating flow at the inlet of the circulating flow reactor.
9. A continuous production device for dimethyl phosphite, characterized in that: It includes a phosphorus trichloride feed port (1) and a methanol feed port (2), both of which are connected to a circulating flow reactor (3); A primary deacidification kettle (4), a secondary deacidification kettle (5) and a crude ester tank (6) are sequentially arranged after the circulating flow reactor (3); The bottom of the first-stage deacidification kettle (4) is connected to a circulation pump (7), and the circulating flow reactor (3) is externally connected to the circulation pump (7); A micro-distributor (31) is arranged in the circulating flow reactor (3).
10. The continuous production device according to claim 9, characterized in that: The micro-distributor (31) is provided with injection holes (32) arranged on its upper side; Preferably, the phosphorus trichloride feed port (1) is connected to the material feed port (33) of the micro-distributor (31); Preferably, the opening direction of the injection hole (32) is consistent with the circulation flow direction; Preferably, the feeding direction of the material feed port (33) is perpendicular to the circulation flow direction; Preferably, the feeding direction of the methanol feed port (2) is consistent with the circulating flow direction; Preferably, the circulating flow reactor (3) has a jacket heat exchange structure; Preferably, the first deacidification kettle (4) is provided with an overflow port, and the overflow port is connected to the second deacidification kettle (5) through a pipeline; Preferably, the secondary deacidification kettle (5) is provided with an overflow port, and the overflow port is connected to the crude ester tank (6) through a pipeline; Preferably, the bottom of the secondary deacidification kettle (5) is connected to the crude ester tank (6) via a pipeline; Preferably, the first-stage deacidification kettle (4) and the second-stage deacidification kettle (5) are both provided with gas phase outlets, and the gas phase outlets are connected to the first-stage condensation trap (41) and the second-stage condensation trap (51) through pipelines; Preferably, the condensate of the first-stage condensation trap (41) connected to the gas phase outlet of the first-stage deacidification kettle (4) is refluxed to the first-stage deacidification kettle (4), and the condensate of the second-stage condensation trap (51) connected to the gas phase outlet of the second-stage deacidification kettle (5) is refluxed to the second-stage deacidification kettle (5); Preferably, the phosphorus trichloride feed port (1) and the methanol feed port (2) are both provided with flow regulating valves; Preferably, the circulating flow reactor (3), the primary deacidification kettle (4), and the secondary deacidification kettle (5) are all provided with a temperature controller; Preferably, the gas phase outlets of the first-stage condensation collector (41) and the second-stage condensation collector (51) are connected to a tail gas recovery device.
Citation Information
Patent Citations
A dimethyl phosphite synthesis apparatus and process
CN115282873B