Micro-channel production system of ethoxymethylene

Abstract

The utility model provides a micro-channel production system for ethoxymethylene, which belongs to the technical field of chemical production and comprises a plurality of stages of micro-channel reactors sequentially connected in series from front to back and a plurality of stages of rectification devices configured corresponding to the plurality of stages of micro-channel reactors, wherein all stages of rectification devices are connected behind all stages of microchannel reactors in series in a one-to-one correspondence manner. According to the micro-channel production system of the ethoxymethylene, provided by the utility model, the multi-stage micro-channel reactor is matched with the multi-stage rectification device, reaction and rectification are separately completed, and materials are subjected to multi-stage reaction and multi-stage rectification separation, so that the reaction rate and the separation efficiency of the ethoxymethylene are effectively improved, automatic continuous production can be realized, and the production cost is reduced. The energy consumption is reduced, and the production cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical production, and specifically relates to a microchannel production system for ethoxymethylene. Background Art

[0002] Ethoxymethylene is the raw material for the synthesis of pyridone drugs and the antibiotic norfloxacin. It is also an important pharmaceutical synthesis intermediate and occupies an important position in pharmaceutical synthesis.

[0003] At present, the most common synthesis route of ethoxymethylene is to use intermittent reaction distillation, where triethyl orthoformate and diethyl malonate are condensed under the action of a catalyst, and two molecules of ethanol are removed step by step to generate ethoxymethylene. The intermittent reaction process requires repeated heating and cooling of the reactor, resulting in high energy consumption, long reaction time, and low production efficiency; and intermittent operation makes it difficult to achieve continuous and automated production in the reactor, resulting in low efficiency, high energy consumption, and high cost of the entire ethoxymethylene production process. Utility Model Content

[0004] The embodiment of the utility model provides a microchannel production system for ethoxymethylidene, aiming to solve the problems of long reaction time, low production efficiency and high production cost in intermittent production of ethoxymethylidene.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: to provide a microchannel production system for ethoxymethylene, the system comprising: a plurality of microchannel reactors connected in series from front to back and a plurality of distillation devices corresponding to the plurality of microchannel reactors; wherein the distillation devices at each stage are connected in series one by one to the back of the microchannel reactors at each stage.

[0006] In one achievable manner, the system further comprises a mixer connected in series in front of the first-stage microchannel reactor and a first-stage distillation tower arranged behind the final distillation device, and a material recovery pipe is provided between the first-stage distillation tower and the mixer.

[0007] In one achievable manner, the multi-stage distillation devices are all distillation columns, a collector is provided at the bottom of the distillation column, and a heater is configured on the collector.

[0008] In one feasible manner, the discharge port at the bottom of the collector is connected to a material pump, and the outlet of the material pump is connected to the microchannel reactor of the next stage; wherein the outlet of the material pump arranged at the bottom of the final distillation device is connected to the first-stage distillation tower.

[0009] In one achievable manner, the material pump is a plunger pump.

[0010] In one achievable manner, the distillation column has a diameter of 1-2 cm and a length of 1-2 m.

[0011] In one practicable manner, a control valve is provided on the material recovery pipe.

[0012] In one achievable manner, the system further comprises a second-stage distillation tower connected in series after the first-stage distillation tower.

[0013] In one achievable manner, a back pressure valve is provided between the microchannel reactor and the distillation device.

[0014] In one achievable manner, the system includes a four-stage microchannel reactor and a correspondingly configured four-stage distillation device.

[0015] Compared with the prior art, the microchannel production system of ethoxymethylene provided by the utility model has the following beneficial effects: the microchannel reactor usually contains hundreds of millions of microchannels inside, has a very large specific surface area, which is hundreds or even thousands of times the specific surface area of ​​a stirred tank, can achieve instantaneous uniform mixing of materials, has extremely high mass transfer and heat transfer efficiency, and can greatly shorten the reaction cycle; the microchannel reactor of the present application is loaded with a solid catalyst, and the large contact area enables the reaction materials to react quickly to reach reaction equilibrium when passing through the reaction channel, and the unseparated ethanol in the microchannel reaction moves rapidly in the form of gas, plays a role of micro-stirring, and promotes the reaction; and a distillation device is used to achieve distillation separation, and the ethanol generated by the reaction is removed by distillation.

[0016] The present application adopts a production system in which a multi-stage microchannel reactor is combined with a multi-stage distillation device. The reaction and distillation are completed separately. The materials are subjected to multi-stage reaction and multi-stage distillation separation, which effectively improves the reaction rate and separation efficiency of ethoxymethylene, can realize automatic continuous production, reduce energy consumption, and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the process structure of a microchannel production system for ethoxymethylene provided in an embodiment of the utility model; DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] See also Figure 1The microchannel production system of ethoxymethylidene provided by the utility model is now described. The microchannel production system of ethoxymethylidene comprises: a multi-stage microchannel reactor connected in series from front to back and a multi-stage rectification device configured corresponding to the multi-stage microchannel reactor; wherein the rectification devices at each stage are connected in series one by one to the back of the microchannel reactor at each stage.

[0020] The utility model provides a microchannel production system for ethoxymethylene, wherein each level of microchannel reactor and distillation device are provided with a solid acid catalyst filling for promoting the reaction; the microchannel reactor usually contains hundreds of millions of microchannels, has a very large specific surface area, which is hundreds or even thousands of times the specific surface area of ​​a stirring kettle, can achieve instantaneous uniform mixing of materials, has extremely high mass transfer and heat transfer efficiency, and can greatly shorten the reaction cycle; the microchannel reactor of the present application is loaded with a solid catalyst, and the large contact area enables the reaction materials to react quickly to reach a reaction equilibrium when passing through the reaction channel, and the unseparated ethanol in the microchannel reaction moves rapidly in a gaseous form, plays a role of micro-stirring, and promotes the reaction; the distillation device is used to achieve distillation separation, and the ethanol generated by the reaction is removed by distillation.

[0021] The present application adopts a production system in which a multi-stage microchannel reactor is combined with a multi-stage distillation device. Each stage of the microchannel reactor is equipped with a set of distillation devices to separate the reaction and distillation. The material undergoes multi-stage reaction and multi-stage distillation separation, which effectively improves the reaction rate and separation efficiency of ethoxymethylene, can realize automatic and continuous production, reduce energy consumption, and reduce production costs.

[0022] In conjunction with the production system provided in this application, taking a four-stage microchannel reactor configured with a four-stage distillation column as an example, the production process of ethoxymethylidene is described in detail:

[0023] In the first step, triethyl orthoformate and diethyl malonate are mixed uniformly at a molar ratio of 1.2 to 1.8:1, and then pumped into the first-stage microchannel reactor by a plunger pump at a certain flow rate, and the inlet pressure is controlled at 1.0 to 1.5 MPa. The reaction material stays in the first-stage microchannel reactor for 3 to 5 minutes, and the microchannel reaction temperature is maintained at 200°C-250°C. The reaction temperature of 200°C-250°C is maintained under positive pressure in the microchannel reactor to increase the reaction rate.

[0024] In the second step, the reaction materials enter the first-stage distillation device through the back pressure valve. The intermediate feed of the first-stage distillation device, ethanol gas and part of the flashed raw materials directly enter the distillation section. A small amount of reflux is generated at the top of the distillation column to produce by-product ethanol. The liquid phase enters the stripping section, undergoes a partial reaction on the filler, and ethanol is separated at the same time.

[0025] In the third step, a collector with a heater is provided at the bottom of each level of distillation device. The material is heated in the collector, and the collector temperature is controlled at 150-160°C. A small amount of triethyl orthoformate is vaporized to maintain the distillation. At the same time, the discharge port at the bottom of the collector is connected to a plunger pump, which pumps the primary reactant to the second-stage microchannel reactor for secondary reaction. The residence time of the material in the first-stage distillation device is 3-5 minutes.

[0026] In the fourth step, the primary reactants enter the second-stage microchannel reactor, quickly reach equilibrium again at a high temperature of 200°C-250°C, and then enter the second-stage distillation device to distill and remove the ethanol generated by the reaction, and then pass through the third-stage microchannel reactor and the third-stage distillation device in sequence, and enter the fourth-stage microchannel reactor and the fourth-stage distillation device to complete the reaction.

[0027] In the fifth step, the materials that have completed the reaction are separated again to obtain recovered triethyl orthoformate and crude product. The crude product is subjected to high negative pressure distillation to extract the finished product at the top, and a small amount of high boiling point substances are collected at the bottom; the triethyl orthoformate is returned to the mixer to continue the reaction.

[0028] Compared with the same quality of raw materials, after four-stage reaction, this system can effectively improve the reaction rate and separation efficiency of ethoxymethylene. The entire production is carried out continuously and can adapt to and configure higher automation, shortening the reaction time from 18h-25h of intermittent production time to 30-50min, greatly improving production efficiency.

[0029] In some embodiments, Figure 1 As shown, the system also includes a mixer connected in series in front of the first-stage microchannel reactor and a first-stage distillation tower arranged behind the final distillation device, and a material recovery pipe is arranged between the first-stage distillation tower and the mixer. The reactants after the final distillation device are separated by the first-stage distillation tower to obtain triethyl orthoformate and a crude product. The triethyl orthoformate returns to the mixer through the material recovery pipe to continue the reaction; the crude product is separated by the second-stage distillation tower to obtain the final product.

[0030] In some embodiments, the multi-stage distillation devices are all distillation columns, and a collector (not shown in the figure) is arranged at the bottom of the distillation column, and a heater is arranged on the collector. The heater arranged at the bottom preheats the reaction materials, keeps the bottom of the separation device at a higher temperature, and can well preheat the next stage microchannel reactor, thereby improving the reaction rate and effect.

[0031] In some embodiments, the discharge port at the bottom of the collector is connected to a material pump (not shown in the figure), and the outlet of the material pump is connected to the next-stage microchannel reactor; wherein the outlet of the material pump configured at the bottom of the final distillation device is connected to the first-stage distillation column. The reaction material in the distillation column is pumped into the next-stage microchannel reactor by the material pump for reaction.

[0032] In some embodiments, the material pump is a plunger pump. The plunger pump is an important device in the hydraulic system. It relies on the reciprocating motion of the plunger in the cylinder to change the volume of the sealed working chamber to achieve oil suction and oil pressure. The plunger pump has the advantages of high rated pressure, compact structure, high efficiency and convenient flow regulation. The plunger pump is widely used in high pressure, large flow and flow regulation occasions.

[0033] In some embodiments, the distillation column has a diameter of 1-2 cm and a length of 1-2 m. The distillation column has a large aspect ratio to improve the degree of distillation separation; the distillation column is a packed column with a diameter of 1 cm-2 cm and a length of 1 m-2 m, and the packing of the packed column is also loaded with a catalyst to promote the reaction.

[0034] In some embodiments, a control valve is provided on the material recovery pipe to control the material recovery and the recovery flow rate as required.

[0035] In some embodiments, Figure 1 As shown, the system also includes a second distillation tower connected in series behind the first distillation tower. The second distillation tower is used to distill and separate the crude product produced by the first distillation tower into finished products to improve the purity of the finished products.

[0036] In some embodiments, a back pressure valve is provided between the microchannel reactor and the distillation device, and the reactants in the microchannel reactor enter the distillation device through the back pressure valve.

[0037] In some embodiments, Figure 1 As shown, the system includes a four-stage microchannel reactor and a corresponding four-stage distillation device. The present embodiment shows a four-stage reaction, and two, three, five, six or more stages of reaction can also be configured according to production design requirements.

[0038] Explain that both distillation columns and distillation towers are important separation devices in industry, and their structural forms have certain differences. Generally speaking, the distillation column has a large aspect ratio and looks like a long stick. It is placed directly inside the reactor, with ventilation at the top and evaporation and reflux liquid at the bottom, so that the two are constantly circulating in the column, and separation is achieved under the interaction of gas and liquid.

[0039] The distillation tower places fillers in the column to form a certain flow rate difference between the fillers and the inside and outside, forming a larger contact surface and time, and then achieving material separation. The long diameter of the distillation tower is much smaller than that of the distillation column, because the fillers are inserted in the column, and it is necessary to ensure that the flow can pass through the filler layer well, so that the separated materials can flow along the column wall without being trapped in the middle.

[0040] The difference between the working principles of distillation columns and distillation towers: In terms of working principles, the difference between distillation columns and towers lies mainly in the different heating methods. In a distillation column, the evaporating liquid is condensed and refluxed after absorbing heat and evaporating, thereby achieving separation. In a distillation tower, the liquid on the packing evaporates, the vapor flows upward, and can only flow back into the packing after being condensed, finally achieving separation. As a simple and easy-to-operate separation device, the distillation column is easy to operate and can be easily promoted from the laboratory to the factory production line; while the distillation tower can achieve efficient separation and large-scale production of various substances, but requires more complicated steps in operation and maintenance.

[0041] The present application configures a distillation column after the microchannel reactor, and uses a distillation tower for the final product processing, which is selected in actual use based on comprehensive factors such as separation effect and requirements, convenience of equipment use and efficiency.

[0042] The following is an example of producing ethoxymethylidene using a microchannel reactor with a channel inner diameter of 6.0 mm and a length of 1-3 m according to the production system provided by the present application:

[0043] Example 1

[0044] like Figure 1 As shown, the distillation column has a diameter of 1 cm and a length of 1 m; triethyl orthoformate and diethyl malonate are mixed evenly in a mixer at a molar ratio of 1.2:1, and the materials are pumped into the first-stage microchannel reactor by a plunger pump, and the inlet pressure is controlled to be 1.0 MPa. The reaction materials stay in the first-stage microchannel reactor for 3 minutes, and the microchannel reaction temperature is controlled to be 200°C. The materials enter the first-stage distillation column through the back pressure valve, and the materials are fed from the middle of the first-stage distillation column. The ethanol gas and the flashed raw materials enter the distillation section. A small amount of reflux is generated at the top of the distillation column to produce ethanol. The liquid phase enters the stripping section, partially reacts on the filler, and ethanol is separated at the same time.

[0045] The liquid material is heated by the collector below the first-stage distillation column and then pumped into the second-stage microchannel reactor through a plunger pump. It stays in the second-stage microchannel reactor for 3 minutes. The reaction temperature in the second-stage microchannel reactor is 200°C. Then it enters the second-stage distillation column, where the ethanol generated by the reaction is distilled away. It passes through the third-stage microchannel reactor and the third-stage distillation column in turn, and then enters the fourth-stage microchannel reactor and the fourth-stage distillation column to complete the reaction.

[0046] The materials after the reaction are passed through the first stage distillation tower to recover triethyl orthoformate and crude product. The triethyl orthoformate is returned to the mixer; the crude product is taken out from the top of the second stage distillation tower with high negative pressure; after continuous feeding for 6 hours, it is determined that the conversion rate of diethyl malonate is 98.2%.

[0047] Example 2

[0048] like Figure 1 As shown, the distillation column has a diameter of 1 cm and a length of 1 m; triethyl orthoformate and diethyl malonate are mixed evenly in a mixer at a molar ratio of 1.5:1, and the materials are pumped into the first-stage microchannel reactor by a plunger pump, and the inlet pressure is controlled at 1.2 MPa. The reaction materials stay in the first-stage microchannel reactor for 4 minutes, and the microchannel reaction temperature is controlled at 230°C. The materials enter the first-stage distillation column through the back pressure valve, and the materials are fed from the middle of the first-stage distillation column. Ethanol gas and flashed raw materials enter the distillation section, and a small amount of reflux is generated at the top of the distillation column to extract ethanol. The liquid phase enters the stripping section, partially reacts on the filler, and ethanol is separated at the same time.

[0049] The liquid material is heated by the collector and then pumped into the second-stage microchannel reactor through a plunger pump. It stays in the second-stage microchannel reactor for 4 minutes. The reaction temperature of the second-stage microchannel is 230°C. Then it enters the second-stage distillation column to remove the ethanol generated by the reaction by distillation. It passes through the third-stage microchannel reactor and the third-stage distillation column in turn, and enters the fourth-stage microchannel reactor and the fourth-stage distillation column to complete the reaction.

[0050] The materials after the reaction are passed through the first stage distillation tower to recover triethyl orthoformate and crude product, triethyl orthoformate is returned to the mixer, and the crude product is taken out from the top of the second stage distillation tower under high negative pressure. After 7 hours of continuous feeding, the conversion rate of diethyl malonate is measured to be 98.4%.

[0051] Example 3

[0052] like Figure 1 As shown, the distillation column has a diameter of 2 cm and a length of 2 m; triethyl orthoformate and diethyl malonate are mixed evenly in a mixer at a molar ratio of 1.8:1, and the materials are pumped into the first-stage microchannel reactor by a plunger pump, and the inlet pressure is controlled at 1.5 MPa. The reaction materials stay in the first-stage microchannel reactor for 5 minutes, and the microchannel reaction temperature is controlled at 250°C. The materials enter the first-stage distillation column through the back pressure valve, and the materials are fed from the middle of the first-stage distillation column. The ethanol gas and the flashed raw materials enter the distillation section, and a small amount of reflux is generated at the top of the distillation column to extract ethanol. The liquid phase enters the stripping section, partially reacts on the filler, and ethanol is separated at the same time.

[0053] The liquid material is heated by the collector and then pumped into the second-stage microchannel reactor through a plunger pump. It stays in the second-stage microchannel reactor for 5 minutes. The reaction temperature of the second-stage microchannel reactor is 250°C. Then it enters the second-stage distillation column to remove the ethanol generated by the reaction by distillation. It passes through the third-stage microchannel reactor and the third-stage distillation column in turn, and enters the fourth-stage microchannel reactor and the fourth-stage distillation column to complete the reaction.

[0054] The materials after the reaction are passed through the first-stage distillation tower to obtain recovered triethyl orthoformate and crude product. The recovered triethyl orthoformate is returned to the mixer, and the crude product is taken out as the finished product at the top of the second-stage distillation tower with high negative pressure. After continuous feeding for 8 hours, it is determined that the conversion rate of diethyl malonate is 98.5%.

[0055] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microchannel production system for ethoxymethylene, characterized in that: The system comprises: a plurality of microchannel reactors connected in series from front to back and a plurality of distillation devices corresponding to the plurality of microchannel reactors; wherein the distillation devices at each stage are connected in series one by one behind the plurality of microchannel reactors at each stage.

2. The microchannel production system of ethoxymethylene as claimed in claim 1, characterized in that: The system also includes a mixer connected in series in front of the first-stage microchannel reactor and a first-stage distillation tower arranged behind the final distillation device, and a material recovery pipe is arranged between the first-stage distillation tower and the mixer.

3. The microchannel production system of ethoxymethylene as claimed in claim 2, characterized in that: The multi-stage distillation devices are all distillation columns, a collector is provided at the bottom of the distillation column, and a heater is arranged on the collector.

4. The microchannel production system of ethoxymethylene as claimed in claim 3, characterized in that: The discharge port at the bottom of the collector is connected to a material pump, and the outlet of the material pump is connected to the microchannel reactor of the next stage; wherein the outlet of the material pump arranged at the bottom of the final distillation device is connected to the first distillation tower.

5. The microchannel production system of ethoxymethylene as claimed in claim 4, characterized in that: The material pump is a plunger pump.

6. The microchannel production system of ethoxymethylene as claimed in claim 3, characterized in that: The distillation column has a diameter of 1-2 cm and a length of 1-2 m.

7. The microchannel production system of ethoxymethylene as claimed in claim 2, characterized in that: The material recovery pipe is provided with a control valve.

8. The microchannel production system of ethoxymethylene as claimed in claim 2, characterized in that: The system further comprises a second-stage distillation tower connected in series after the first-stage distillation tower.

9. The microchannel production system of ethoxymethylene as claimed in claim 1, characterized in that: A back pressure valve is arranged between the microchannel reactor and the distillation device.

10. The microchannel production system of ethoxymethylene according to claim 1, characterized in that: The system comprises a four-stage microchannel reactor and a correspondingly configured four-stage rectification device.

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