Micro-reaction continuous production method and device for hydroxyl acrylate
阅读说明：本技术 丙烯酸羟基酯微反应连续化生产方法及装置 (Micro-reaction continuous production method and device for hydroxyl acrylate ) 是由 杨双兵 张胜慧 李燕 张少泽 于 2021-09-23 设计创作，主要内容包括：本发明公开一种丙烯酸羟基酯微反应连续化生产方法及装置,包括以下步骤：将辅料加入到第一原料中,搅拌使溶解成原料液；将所述原料液和第二原料送入微混合器中,在不高于20℃的温度下混合得到混合液；将所述混合液送入微通道反应器中进行反应,得到丙烯酸羟基酯；其中,所述第一原料包括丙烯酸或甲基丙烯酸,所述第二原料包括环氧乙烷或环氧丙烷,所述辅料包括催化剂和阻聚剂。本发明方法不仅很好地提高了换热效率和流体混合效率,大大提高了反应效率,而且实现了连续化生产,进一步提高了生产效率。(The invention discloses a micro-reaction continuous production method and a device of hydroxyl acrylate, which comprises the following steps: adding auxiliary materials into the first raw material, and stirring to dissolve the auxiliary materials into a raw material liquid; feeding the raw material liquid and the second raw material into a micro mixer, and mixing at a temperature not higher than 20 ℃ to obtain a mixed liquid; feeding the mixed solution into a microchannel reactor for reaction to obtain hydroxyl acrylate; the first raw material comprises acrylic acid or methacrylic acid, the second raw material comprises ethylene oxide or propylene oxide, and the auxiliary material comprises a catalyst and a polymerization inhibitor. The method not only improves the heat exchange efficiency and the fluid mixing efficiency well, greatly improves the reaction efficiency, but also realizes continuous production and further improves the production efficiency.)
1. The continuous production method of the acrylic acid hydroxyl ester by the micro-reaction is characterized by comprising the following steps:
s10, adding the auxiliary materials into the first raw material, and stirring to dissolve the auxiliary materials into a raw material liquid;
s20, feeding the raw material liquid and the second raw material into a micro mixer, and mixing at a temperature not higher than 20 ℃ to obtain a mixed liquid;
s30, feeding the mixed solution into a microchannel reactor for reaction to obtain hydroxyl acrylate;
the first raw material comprises acrylic acid or methacrylic acid, the second raw material comprises ethylene oxide or propylene oxide, and the auxiliary material comprises a catalyst and a polymerization inhibitor.
2. The continuous production method of hydroxyl acrylate by micro-reaction according to claim 1, wherein the microchannel reactor comprises a temperature rising section, a reaction section, a strengthening reaction section, a temperature holding section and a temperature lowering section which are arranged in the feeding direction in this order, wherein:
the temperature of the temperature rising section is 50-60 ℃, the temperature of the reaction section is 60-70 ℃, the temperature of the strengthening reaction section is 75-90 ℃, the temperature of the heat preservation section is 75-90 ℃, and the temperature of the temperature reduction section is not higher than 55 ℃;
the pressure of the microchannel reactor is not higher than 0.3 MPa.
3. The method of claim 2, wherein the temperature of the reaction section is 65 ℃, the temperature of the enhanced reaction section is 85 ℃, and the temperature of the soaking section is 85 ℃; and/or the presence of a gas in the gas,
the microchannel reactor is provided with a heat exchange channel for heat conduction oil to flow and a main channel arranged in the heat exchange channel, the main channel is used for allowing the mixed liquid to react, and the temperature of the heat conduction oil flowing in the heat exchange channel corresponding to the reaction section, the enhanced reaction section and the heat preservation section is 15-25 ℃.
4. The method for continuously producing hydroxy acrylate by micro-reaction according to claim 1, wherein in step S20, the flow rate of the raw material liquid is 5 to 10ml/min, and the flow rate of the second raw material is 3 to 6 ml/min.
5. The method of claim 1, wherein the catalyst comprises chromium chloride or chromium acetate; and/or the presence of a gas in the gas,
the polymerization inhibitor comprises nitroxide radical piperidone.
6. The utility model provides a hydroxyl acrylate micro-reaction serialization apparatus for producing which characterized in that, is including the preparation cauldron that is used for preparing raw materials liquid, the raw materials jar that is used for storing the second raw materials, micromixer, the microchannel reactor of constituteing by a plurality of microchannels are established ties, storage tank and temperature control device, wherein:
the preparation kettle and the raw material tank are communicated with the micro mixer, the plurality of micro channels and the storage tank are communicated in sequence, and the micro mixer and each micro channel are provided with a heat exchange channel and a main channel arranged in the heat exchange channel;
the temperature control device comprises temperature detectors and a controller, wherein the temperature detectors are used for detecting the temperatures in the main channels and the heat exchange channels, and the controller is used for controlling the flow of the heat exchange fluid in the heat exchange channels according to the temperatures detected by the temperature detectors.
7. The continuous production apparatus for micro-reaction of hydroxyl acrylate according to claim 6, wherein the plurality of micro-channels comprises a first micro-channel having a first heat exchange channel, a second micro-channel having a second heat exchange channel, a third micro-channel having a third heat exchange channel, a fourth micro-channel having a fourth heat exchange channel, and a fifth micro-channel having a fifth heat exchange channel, which are sequentially connected in a feed direction, and the micro-mixer has a premix heat exchange channel;
the micro-reaction continuous production device for the hydroxyl acrylate further comprises a condenser, wherein the condenser is provided with a high-temperature inlet and a low-temperature outlet, the inlet of the premixing heat exchange channel, the inlet of the second heat exchange channel, the inlet of the third heat exchange channel, the inlet of the fourth heat exchange channel and the inlet of the fifth heat exchange channel are communicated with the low-temperature outlet, the outlet of the premixing heat exchange channel, the outlet of the first heat exchange channel and the outlet of the fifth heat exchange channel are communicated with the high-temperature inlet, and the outlet of the second heat exchange channel, the outlet of the third heat exchange channel and the outlet of the fourth heat exchange channel are communicated with the inlet of the first heat exchange channel.
8. The continuous production apparatus for micro-reaction of hydroxy acrylate according to claim 7, wherein a flow meter is provided at the inlet end of each heat exchange channel, and each flow meter is electrically connected to the controller; and/or the presence of a gas in the gas,
the micro-reaction continuous production device for the hydroxyl acrylate further comprises a heat exchange pipeline, one end of the heat exchange pipeline is communicated with the low-temperature outlet, the other end of the heat exchange pipeline is communicated with the inlet of the second heat exchange channel, the inlet of the third heat exchange channel, the inlet of the fourth heat exchange channel and the inlet of the fifth heat exchange channel, a heating element and a temperature sensor are arranged on the heat exchange pipeline, the heating element is used for heating heat exchange fluid in the heat exchange pipeline, the temperature sensor is arranged at one end, far away from the low-temperature outlet, of the heating element and used for detecting the temperature in the heat exchange pipeline, and the temperature sensor and the heating element are electrically connected with the controller.
9. The continuous production apparatus of claim 6, wherein the continuous production apparatus of acrylic acid hydroxy ester comprises two preparation kettles arranged in parallel, and a valve is disposed at the bottom of each preparation kettle.
10. The continuous production apparatus for the micro-reaction of hydroxyl acrylate according to claim 6, wherein a pressure regulating valve is provided between the microchannel reactor and the storage tank; and/or the presence of a gas in the gas,
a pressure regulating valve and a metering pump are arranged between the preparation kettle and the micro mixer; and/or the presence of a gas in the gas,
and a pressure regulating valve and a metering pump are arranged between the raw material tank and the micro mixer.
Technical Field
The invention relates to the technical field of chemical production, in particular to a micro-reaction continuous production method and a device for hydroxyl acrylate.
Background
Hydroxyethyl acrylate is a transparent liquid substance with two active functional groups, and has various application ways in industrial production, specifically, hydroxyethyl acrylate can be copolymerized with many monomers such as acrylic acid and ester, acrolein, acrylonitrile, acrylamide, methacrylonitrile, vinyl chloride, styrene and the like, and the obtained product can be used for treating fibers and can improve the water resistance, solvent resistance, crease resistance and water resistance of the fibers after treatment; can also be used for manufacturing thermosetting coatings and synthetic rubbers with excellent performance, and used as lubricating oil additives and the like; in the aspect of an adhesive, hydroxyethyl acrylate is copolymerized with a vinyl monomer, so that the bonding strength of the adhesive can be improved; in the aspect of paper processing, hydroxyethyl acrylate is used for preparing acrylic emulsion for coating, and the water resistance and the strength of the acrylic emulsion can be improved.
At present, the most common route in industry is that acrylic acid, catalyst, polymerization inhibitor and the like are put into a reaction kettle, then the temperature is raised to the reaction temperature, and then ethylene oxide is slowly dripped to generate hydroxyethyl acrylate. The preparation method has the defects of long reaction time and low reaction conversion rate, and simultaneously, a large amount of materials stay in the kettle for a long time, and once leakage occurs, great safety and environmental protection accidents can be caused.
Disclosure of Invention
The invention mainly aims to provide a method and a device for micro-reaction continuous production of hydroxyl acrylate, and aims to solve the problem of long reaction time of the existing industrial preparation method.
In order to achieve the above object, the present invention provides a continuous production method of hydroxyl acrylate by micro-reaction, comprising the following steps:
s10, adding the auxiliary materials into the first raw material, and stirring to dissolve the auxiliary materials into a raw material liquid;
s20, feeding the raw material liquid and the second raw material into a micro mixer, and mixing at a temperature not higher than 20 ℃ to obtain a mixed liquid;
s30, feeding the mixed solution into a microchannel reactor for reaction to obtain hydroxyl acrylate;
the first raw material comprises acrylic acid or methacrylic acid, the second raw material comprises ethylene oxide or propylene oxide, and the auxiliary material comprises a catalyst and a polymerization inhibitor.
Optionally, the microchannel reactor includes a temperature rising section, a reaction section, a strengthened reaction section, a heat preservation section, and a temperature reduction section, which are sequentially arranged along a feeding direction, wherein:
the temperature of the temperature rising section is 50-60 ℃, the temperature of the reaction section is 60-70 ℃, the temperature of the strengthening reaction section is 75-90 ℃, the temperature of the heat preservation section is 75-90 ℃, and the temperature of the temperature reduction section is not higher than 55 ℃;
the pressure of the microchannel reactor is not higher than 0.3 MPa.
Optionally, the temperature of the reaction section is 65 ℃, the temperature of the strengthening reaction section is 85 ℃, and the temperature of the heat preservation section is 85 ℃; and/or the presence of a gas in the gas,
the microchannel reactor is provided with a heat exchange channel for heat conduction oil to flow and a main channel arranged in the heat exchange channel, the main channel is used for allowing the mixed liquid to react, and the temperature of the heat conduction oil flowing in the heat exchange channel corresponding to the reaction section, the enhanced reaction section and the heat preservation section is 15-25 ℃.
Optionally, in step S20, the flow rate of the raw material liquid is 5 to 10ml/min, and the flow rate of the second raw material is 3 to 6 ml/min.
Optionally, the catalyst comprises chromium chloride or chromium acetate; and/or the presence of a gas in the gas,
the polymerization inhibitor comprises nitroxide radical piperidone.
The invention also provides a micro-reaction continuous production device for the hydroxyl acrylate, which comprises a preparation kettle for preparing the raw material liquid, a raw material tank for storing a second raw material, a micro mixer, a micro-channel reactor consisting of a plurality of micro-channels connected in series, a storage tank and a temperature control device, wherein:
the preparation kettle and the raw material tank are communicated with the micro mixer, the plurality of micro channels and the storage tank are communicated in sequence, and the micro mixer and each micro channel are provided with a heat exchange channel and a main channel arranged in the heat exchange channel;
the temperature control device comprises temperature detectors and a controller, wherein the temperature detectors are used for detecting the temperatures in the main channels and the heat exchange channels, and the controller is used for controlling the flow of the heat exchange fluid in the heat exchange channels according to the temperatures detected by the temperature detectors.
Optionally, the plurality of microchannels comprise a first microchannel, a second microchannel, a third microchannel, a fourth microchannel and a fifth microchannel which are sequentially communicated along a feeding direction, wherein the first microchannel is provided with a first heat exchange channel, the second microchannel is provided with a second heat exchange channel, the third microchannel is provided with a third heat exchange channel, the fourth microchannel is provided with a fourth heat exchange channel, the fifth microchannel is provided with a fifth heat exchange channel, and the micromixer is provided with a premixing heat exchange channel;
the micro-reaction continuous production device for the hydroxyl acrylate further comprises a condenser, wherein the condenser is provided with a high-temperature inlet and a low-temperature outlet, the inlet of the premixing heat exchange channel, the inlet of the second heat exchange channel, the inlet of the third heat exchange channel, the inlet of the fourth heat exchange channel and the inlet of the fifth heat exchange channel are communicated with the low-temperature outlet, the outlet of the premixing heat exchange channel, the outlet of the first heat exchange channel and the outlet of the fifth heat exchange channel are communicated with the high-temperature inlet, and the outlet of the second heat exchange channel, the outlet of the third heat exchange channel and the outlet of the fourth heat exchange channel are communicated with the inlet of the first heat exchange channel.
Optionally, a flow meter is arranged at an inlet end of each heat exchange channel; and/or the presence of a gas in the gas,
the micro-reaction continuous production device for the hydroxyl acrylate further comprises a heat exchange pipeline, one end of the heat exchange pipeline is communicated with the low-temperature outlet, the other end of the heat exchange pipeline is communicated with the inlet of the second heat exchange channel, the inlet of the third heat exchange channel, the inlet of the fourth heat exchange channel and the inlet of the fifth heat exchange channel, a heating element and a temperature sensor are arranged on the heat exchange pipeline, the heating element is used for heating heat exchange fluid in the heat exchange pipeline, and the temperature sensor is arranged at one end, far away from the low-temperature outlet, of the heating element and used for detecting the temperature in the heat exchange pipeline.
Optionally, the hydroxyl acrylate micro-reaction continuous production device comprises two preparation kettles arranged in parallel, and a valve is arranged at the bottom of each preparation kettle.
Optionally, a pressure regulating valve is arranged between the microchannel reactor and the storage tank; and/or the presence of a gas in the gas,
a pressure regulating valve and a metering pump are arranged between the preparation kettle and the micro mixer; and/or the presence of a gas in the gas,
and a pressure regulating valve and a metering pump are arranged between the raw material tank and the micro mixer.
According to the technical scheme provided by the invention, the auxiliary materials such as the catalyst and the like are dissolved in the first raw material, and then the first raw material and the second raw material are mixed at a molecular level by adopting the micro mixer, so that the mixing uniformity is improved, and the side reaction is well inhibited when the mixing temperature is below 20 ℃; the invention adopts the microchannel reactor to replace the traditional stirred tank reactor, thereby not only improving the heat exchange efficiency and the fluid mixing efficiency well and greatly improving the reaction efficiency, but also realizing continuous production and further improving the production efficiency; meanwhile, the micro mixer and the micro channel reactor enable the material stock in the reaction process to be less, the problem of safety and environmental protection caused by material leakage is avoided, and the safety is high. In addition, the method is simultaneously suitable for producing hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate, and has good adaptability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic structural diagram of an embodiment of a continuous production apparatus for micro-reaction of hydroxy acrylate according to the present invention.
The reference numbers illustrate:
reference numerals
Name (R)
Reference numerals
Name (R)
1
Preparation kettle
45
Fifth microchannel
11
Stirrer
451
Fifth heat exchange channel
12
Feeding mechanism
5
Storage tank
2
Raw material tank
6
Condenser
3
Micro mixer
61
High temperature inlet
31
Premix heat exchange passages
62
Low temperature outlet
4
Micro-channel reactor
7
Flow meter
41
A first microchannel
8
Heat exchange pipeline
411
First heat exchange channel
91
Pressure regulating valve
42
Second microchannel
92
Metering pump
421
Second heat exchange channel
93
Sampling pipeline
43
Third microchannel
94
Valve gate
431
Third heat exchange channel
95
Heating element
44
A fourth microchannel
96
Temperature sensor
441
Fourth heat exchange channel
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a micro-reaction continuous production device for hydroxyl acrylate. The device for producing the acrylic hydroxyl ester has the advantages of high efficiency, energy conservation, good safety and high reaction efficiency.
Referring to fig. 1, the micro-reaction continuous production apparatus for hydroxyl acrylate comprises a preparation kettle 1, a raw material tank 2, a micro mixer 3, a micro channel reactor 4, a storage tank 5 and a temperature control device (not shown in the figure). The preparation kettle 1 and the raw material tank 2 are both communicated with the micro mixer 3, the plurality of micro channels and the storage tank 5 are sequentially communicated, and the micro mixer 3 and each micro channel are provided with a heat exchange channel and a main channel arranged in the heat exchange channel; the temperature control device comprises temperature detectors and a controller, wherein the temperature detectors are used for detecting the temperatures in the main channels and the heat exchange channels, and the controller is used for controlling the flow of the heat exchange fluid in the heat exchange channels according to the temperatures detected by the temperature detectors.
The preparation kettle 1 is used for mixing auxiliary materials such as a catalyst and the like with a first raw material to obtain a raw material liquid, wherein the first raw material comprises acrylic acid or methacrylic acid; the preparation kettle 1 is provided with a stirrer 11 and a feeding mechanism 12, and the feeding mechanism 12 is used for feeding solid auxiliary materials into the kettle. Further, preferably, the micro-reaction continuous production device for hydroxyl acrylate in the embodiment includes two preparation kettles 1 arranged in parallel, a kettle bottom discharge port of each preparation kettle 1 is communicated with one conveying pipeline through a pipeline, and the conveying pipeline is communicated with the micro mixer 3. Meanwhile, a valve 94 is arranged at the bottom of each preparation kettle 1. Setting two preparation kettles 1 as a kettle A and a kettle B, so that during production, a valve 94 of the kettle A is opened, a valve 94 of the kettle B is closed, feeding can be performed through the kettle A, meanwhile, material is prepared in the kettle B, and accordingly, the time for adding and dissolving auxiliary materials is saved; in addition, when one of the preparation kettles 1 needs to be maintained or cleaned, the production is not affected.
Further, a pressure regulating valve 91 and a metering pump 92 are provided between the preparation tank 1 and the micromixer 3, so that the flow rate and pressure of the raw material liquid can be controlled. The pressure regulating valve 91 and the metering pump 92 can be electrically connected with the controller, so that the flow and the pressure of the raw material liquid can be controlled by the controller, and automatic production is realized.
The feed tank 2 is used to store a second feed comprising ethylene oxide or propylene oxide. Further, a pressure regulating valve 91 and a metering pump 92 are provided between the raw material tank 2 and the micromixer 3, so that the flow rate and pressure of the raw material liquid can be controlled. The pressure regulating valve 91 and the metering pump 92 can be electrically connected with the controller, so that the flow and the pressure of the second raw material can be controlled by the controller, and automatic production is realized.
The micro mixer 3 is provided with a main channel and a pre-mixing heat exchange channel 31, the main channel is provided with two feed inlets which are respectively communicated with the preparation kettle 1 and the raw material tank 2, so that the raw material liquid in the preparation kettle 1 and the second raw material in the raw material tank 2 can be mixed in the main channel of the micro mixer 3, the mixing at a molecular level is realized, and the mixing uniformity and the mixing efficiency are improved. Specifically, the micromixer 3 may be a T-type micromixer 3 or a Y-type micromixer 3. The heat exchange channel of the micro mixer 3 is used for heat conducting oil to flow so as to control the temperature of the main channel.
In some embodiments, the main channel and the premix heat exchange channel 31 of the micro mixer 3 are both provided with a temperature detector, the temperature detector is electrically connected to the controller, and the controller controls the flow rate of the heat exchange fluid in the premix heat exchange channel 31 according to the detection result of the temperature detector, for example, when the temperature in the main channel is higher than a preset temperature, the controller can control the flow rate of the heat exchange fluid in the premix heat exchange channel 31 to increase so as to reduce the temperature in the main channel.
The micro-channel reactor 4 is formed by connecting a plurality of micro-channels in series; specifically, the plurality of microchannels comprise a first microchannel 41, a second microchannel 42, a third microchannel 43, a fourth microchannel 44 and a fifth microchannel 45 which are sequentially communicated along the feeding direction, and main channels of the first microchannel 41, the second microchannel 42, the third microchannel 43, the fourth microchannel 44 and the fifth microchannel 45 are sequentially communicated so as to allow a mixed solution to flow and react. When the hydroxyl acrylate micro-reaction continuous production device is used for producing hydroxyl acrylate, the first microchannel 41, the second microchannel 42, the third microchannel 43, the fourth microchannel 44 and the fifth microchannel 45 respectively correspond to a heating section, a reaction section, a strengthening reaction section, a heat preservation section and a cooling section which are described in the following production methods. The first microchannel 41 has a first heat exchange channel 411, the second microchannel 42 has a second heat exchange channel 421, the third microchannel 43 has a third heat exchange channel 431, the fourth microchannel 44 has a fourth heat exchange channel 441, the fifth microchannel 45 has a fifth heat exchange channel 451, and the first heat exchange channel 411, the second heat exchange channel 421, the third heat exchange channel 431, the fourth heat exchange channel 441 and the fifth heat exchange channel 451 are each independently arranged so as to facilitate independent temperature control. In view of energy saving and structural simplification, the apparatus for continuous production of hydroxy acrylate by micro reaction further comprises a condenser 6, the condenser 6 has a high temperature inlet 61 and a low temperature outlet 62, the inlet of the pre-mixing heat exchange channel 31, the inlet of the second heat exchange channel 421, the inlet of the third heat exchange channel 431, the inlet of the fourth heat exchange channel 441 and the inlet of the fifth heat exchange channel 451 are all communicated with the low temperature outlet 62, the outlet of the pre-mixing heat exchange channel 31, the outlet of the first heat exchange channel 411 and the outlet of the fifth heat exchange channel 451 are all communicated with the high temperature inlet 61, and the outlet of the second heat exchange channel 421, the outlet of the third heat exchange channel 431 and the outlet of the fourth heat exchange channel 441 are all communicated with the inlet of the first heat exchange channel 411. Therefore, after the high-temperature heat conduction oil is cooled by the condenser 6, low-temperature heat conduction oil is formed, the low-temperature heat conduction oil can be respectively sent to the premixing heat exchange channel 31, the second heat exchange channel 421, the third heat exchange channel 431, the fourth heat exchange channel 441 and the fifth heat exchange channel 451 through pipelines, so that the temperature of the liquid in the corresponding main channel is controlled, then, the heat conduction oil in the second heat exchange channel 421, the third heat exchange channel 431 and the fourth heat exchange channel 441 absorbs heat and is heated up, the heated heat conduction oil is guided into the first heat exchange channel 411 in the embodiment, reaction heat release is effectively utilized, and the liquid in the first microchannel 41 is heated up, and meanwhile, energy consumption is reduced. Meanwhile, the heat conducting oil heated in the premixing heat exchange channel 31, the first heat exchange channel 411 and the fifth heat exchange channel 451 is delivered to the high temperature inlet 61 of the condenser 6 for the next cycle.
Further, each heat transfer channel's entry end is equipped with flowmeter 7, so, can control respectively the flow of conduction oil in each heat transfer channel to realize different temperature control demands. Furthermore, each flowmeter 7 is electrically connected with the controller, so that after the controller receives temperature signals sent by the temperature sensors 96 in each main channel and each heat exchange channel, the controller can control the flow of the heat conduction oil in each heat exchange channel by controlling the opening degree of each flowmeter 7.
In addition, since the temperature requirements of the pre-mixing heat exchange channel 31 and the second heat exchange channel 421, the third heat exchange channel 431, the fourth heat exchange channel 441 and the fifth heat exchange channel 451 for the conduction oil are different, the micro-reaction continuous production device for hydroxyl acrylate further comprises a heat exchange pipe 8, one end of the heat exchange pipe 8 is communicated with the low-temperature outlet 62, and the other end of the heat exchange pipe 8 is simultaneously communicated with the inlet of the second heat exchange channel 421, the inlet of the third heat exchange channel 431, the inlet of the fourth heat exchange channel 441 and the inlet of the fifth heat exchange channel 451, a heating element 95 and a temperature sensor 96 are arranged on the heat exchange pipe 8, the heating element 95 is used for heating the heat exchange fluid in the heat exchange pipe 8, the temperature sensor 96 is disposed at an end of the heating element 95 away from the low temperature outlet 62, and is configured to detect a temperature inside the heat exchange pipe 8. Therefore, the heat conduction oil with the temperature lower than 20 ℃ can be directly input into the premixing heat exchange channel 31, and meanwhile, the heat conduction oil with the temperature lower than 20 ℃ is heated to reach the expected heat conduction oil temperature of the second heat exchange channel 421, the third heat exchange channel 431, the fourth heat exchange channel 441 and the fifth heat exchange channel 451, and then is respectively sent into the second heat exchange channel 421, the third heat exchange channel 431, the fourth heat exchange channel 441 and the fifth heat exchange channel 451. Similarly, the heating element 95 and the temperature sensor 96 are electrically connected to the controller, and the controller controls the heating element 95 to continue to operate when the temperature detected by the temperature sensor 96 does not reach a preset temperature.
In addition, the fourth microchannel 44 of the present embodiment is provided with a sampling pipe 93, and the sampling pipe 93 is communicated with the main channel of the fourth microchannel 44. In production, the reactant in the fourth microchannel 44 is extracted from the sampling pipe 93, and the progress of the reaction can be judged, so that the reaction can be controlled better.
In addition, a pressure regulating valve 91 is arranged between the microchannel reactor 4 and the storage tank 5, so that the pressure of the microchannel reactor 4 can be controlled, and the pressure regulating valve 91 is electrically connected with the controller, so that the automation degree of the whole device is higher. The pressure regulating valve 91 may be a back pressure valve.
The invention further provides a micro-reaction continuous production method of the hydroxyl acrylate. The production method can be implemented by adopting the device, and when the device is used for implementation, the reaction efficiency is higher, the energy consumption is less, and the product qualification rate is higher.
The micro-reaction continuous production method of the hydroxyl acrylate comprises the following steps:
and S10, adding the auxiliary materials into the first raw material, and stirring to dissolve the auxiliary materials into a raw material liquid.
And S20, feeding the raw material liquid and the second raw material into a micro mixer 3, and mixing at a temperature not higher than 20 ℃ to obtain a mixed liquid.
The first raw material comprises acrylic acid or methacrylic acid, the second raw material comprises ethylene oxide or propylene oxide, and the auxiliary material comprises a catalyst and a polymerization inhibitor. Specifically, when the product to be produced is hydroxyethyl acrylate, the first raw material is acrylic acid, and the second raw material is ethylene oxide; when the product is hydroxyethyl methacrylate, the first raw material is methacrylic acid, and the second raw material is ethylene oxide; when the product is hydroxypropyl acrylate, the first raw material is acrylic acid, and the second raw material is propylene oxide; when the product is hydroxypropyl methacrylate, the first feedstock is methacrylic acid and the second feedstock is propylene oxide.
Further, the present invention is not limited to the specific type of catalyst and polymerization inhibitor, and in some embodiments, the catalyst comprises chromium chloride or chromium acetate; the polymerization inhibitor comprises nitroxide radical piperidone. Under the same condition, the chromium chloride and the chromium acetate not only have higher catalytic activity, but also have higher selectivity, and are beneficial to reducing the probability of side reaction.
In this embodiment, the temperature of the main channel of the micro mixer 3 is controlled to be not higher than 20 ℃, so that the mixing process of the first raw material and the second raw material can be performed at a low temperature, the raw materials are prevented from reacting in a non-uniform mixing state, and the generation of byproducts is reduced.
S30, feeding the mixed solution into a microchannel reactor 4 for reaction to obtain hydroxyl acrylate;
the kettle type reaction is limited by heat exchange efficiency, the dripping of the ethylene oxide (propylene oxide) can only be controlled at a certain speed, and temperature runaway is prevented, so that the reaction speed is low. The heat can be effectively removed in time in the microchannel reactor 4 due to the large specific surface area and high heat transfer coefficient. The invention adopts the microchannel reactor 4 for reaction, thereby not only improving the heat exchange efficiency and the fluid mixing efficiency well and greatly improving the reaction efficiency, but also realizing continuous production and further improving the production efficiency; meanwhile, the micro mixer 3 and the micro channel reactor 4 enable the material stock in the reaction process to be less, the safety and environmental protection problems caused by material leakage are avoided, and the safety is high.
Further, the microchannel reactor 4 of this embodiment includes a temperature rising section, a reaction section, a strengthening reaction section, a heat preservation section, and a temperature reduction section, which are sequentially arranged along the feeding direction.
The temperature of the temperature rising section is 50-60 ℃, the temperature rising section is used for pre-heating materials, and the temperature of the temperature rising section is the final temperature to which the mixed liquid in the first micro-channel 41 is heated; the final temperature is 50 to 60 ℃ such as 50 ℃, 51 ℃, 52 ℃, 53 ℃, 54 ℃, 54.5 ℃, 54.8 ℃, 55 ℃, 55.2 ℃, 55.3 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃, 60 ℃ and the like. During specific implementation, high-temperature heat conduction oil with the temperature slightly higher than 50-60 ℃ (for example, 55-65 ℃) is introduced into the first heat exchange channel 411 corresponding to the temperature rising section to achieve pre-temperature rising of materials, and the materials enter the reaction section to start to react after reaching the appropriate reaction temperature (for example, 55 ℃), and as a large amount of heat can be released in material reaction in the subsequent reaction section, the strengthened reaction section and the heat preservation section, the heat conduction oil in the corresponding heat exchange channels can absorb a large amount of heat, at the moment, the corresponding high-temperature heat conduction oil (usually reaching 55-65 ℃) is sent into the first heat exchange channel 411, the utilization of the part of heat can be effectively achieved, and the energy consumption is reduced while the temperature required by the temperature rising section is achieved.
The temperature of the reaction section is the reaction temperature of the liquid in the second microchannel 42, and the temperature of the reaction section is 60 to 70 ℃, for example, 60 ℃, 61 ℃, 62 ℃, 63 ℃, 64 ℃, 65 ℃, 66 ℃, 67 ℃, 68 ℃, 69 ℃, 70 ℃ and the like, preferably 65 ℃. During specific implementation, 15-25 ℃ low-temperature heat conduction oil can be introduced into the second heat exchange channel 421, so that the temperature in the main channel of the second micro channel 42 is maintained at 60-70 ℃, and the reaction is smooth, and the concentration of the raw materials at the initial stage of the reaction is higher, so that the reaction power is high, the reaction is carried out at a lower temperature, and thus, the reaction rate can be ensured, and the side reaction caused by long-time high temperature can be effectively inhibited.
The temperature of the enhanced reaction section is the temperature of the liquid in the main channel of the third microchannel 43, and the temperature of the enhanced reaction section is 75 to 90 ℃, for example, 75 ℃, 76 ℃, 78 ℃, 79 ℃, 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃, 85 ℃, 86 ℃, 87 ℃, 88 ℃, 89 ℃, 90 ℃ and the like, preferably 85 ℃. When the digestion of the raw material reaches more than 90%, the reaction power is reduced, and the reaction is enhanced by increasing the reaction temperature in the embodiment, so that the reaction yield is improved. In specific implementation, 15-25 ℃ low-temperature heat transfer oil can be introduced into the third heat exchange channel 431, so that the temperature in the main channel of the second microchannel 42 is maintained at 75-90 DEG C
The temperature of the heat-retaining section is the temperature of the liquid in the main channel of the fourth microchannel 44, and the temperature of the heat-retaining section is 75 to 90 ℃, for example, 75 ℃, 76 ℃, 78 ℃, 79 ℃, 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃, 85 ℃, 86 ℃, 87 ℃, 88 ℃, 89 ℃, 90 ℃ or the like, preferably 85 ℃. After the reaction strengthening section, most of the raw materials are consumed, and the reaction time is prolonged by arranging the heat preservation section in the embodiment so as to promote the final reaction to be completed, thereby further improving the reaction conversion rate.
The temperature of the cooling section is not higher than 55 ℃, the temperature of the cooling section is the temperature of liquid in the main channel of the fifth micro-channel 45, and the liquid can be cooled by introducing low-temperature heat conduction oil of 15-25 ℃ so as to be conveniently collected in the storage tank 5; the pressure of the microchannel reactor 4 is not higher than 0.3MPa, and in specific implementation, the pressure can be controlled by a pressure regulating valve 91 between the microchannel reactor 4 and the storage tank 5.
In this embodiment, the temperature of the reaction section is 65 ℃, the temperature of the strengthening reaction section is 85 ℃, and the temperature of the holding section is 85 ℃.
Further, in step S20, the flow rate of the raw material liquid is 5 to 10ml/min, and the flow rate of the second raw material is 3 to 6 ml/min. This embodiment has effectively controlled the reaction direction through controlling the flow of raw materials liquid and second raw materials respectively, has reduced the going on of side reaction.
In the technical scheme provided by the invention, the auxiliary materials such as the catalyst and the like are dissolved in the first raw material, and then the first raw material and the second raw material are mixed at a molecular level by adopting the micro mixer 3, so that the mixing uniformity is improved, and the side reaction is well inhibited when the mixing temperature is below 20 ℃; according to the invention, the microchannel reactor 4 is adopted to replace the traditional stirred tank reactor, so that the heat exchange efficiency and the fluid mixing efficiency are well improved, the reaction efficiency is greatly improved, the continuous production is realized, the production efficiency is further improved, the reaction time can be shortened to 30min, and compared with the traditional production method of the reaction kettle feeding reaction, the reaction selectivity is improved by 2%, the consumption of the second raw material is reduced by 0.5%, and the energy consumption is reduced by 20%; meanwhile, the micro mixer 3 and the micro channel reactor 4 enable the material stock in the reaction process to be less, the safety and environmental protection problems caused by material leakage are avoided, and the safety is high. In addition, the method is simultaneously suitable for producing hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate, and has good adaptability.
The above is only a preferred embodiment of the present invention, and it is not intended to limit the scope of the invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall be included in the scope of the present invention.