CN116020370A

CN116020370A - Microchannel reaction device and preparation method of N-methylpyrrolidone

Info

Publication number: CN116020370A
Application number: CN202111249860.5A
Authority: CN
Inventors: 储博钊; 钟思青; 王菊; 马俊
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2021-10-26
Filing date: 2021-10-26
Publication date: 2023-04-28

Abstract

The invention relates to the field of micro-channel devices, and discloses a micro-channel reaction device and a preparation method of N-methyl pyrrolidone, wherein the micro-channel reaction device comprises a mixer with a liquid-phase feed inlet and a gas-phase feed inlet and a reactor which is communicated with the mixer in a sealing way and is provided with a product outlet; the mixer is internally provided with a plurality of nested microscale sleeves, and liquid-phase raw materials and gas-phase raw materials are efficiently mixed in a liquid-phase fluid channel of the mixer and then enter a reactor; the reactor is internally provided with a plurality of groups of overlapped grid plate mixing inserts which are staggered and overlapped to form a zigzag microscale reaction channel, and the reaction raw materials are efficiently reacted in the reactor and ensure that the gas phase raw materials have higher utilization rate. The microchannel reaction device provided by the invention utilizes the microscale effect to effectively strengthen the process of a multiphase reaction system, and simultaneously provides a solution which does not need to additionally introduce a solvent and has lower reaction pressure for the synthesis process of N-methylpyrrolidone, so that the high-efficiency mixed reaction efficiency and good safety in the whole process flow can be ensured.

Description

Microchannel reaction device and preparation method of N-methylpyrrolidone

Technical Field

The invention relates to the field of micro-channel devices, in particular to a micro-channel reaction device and a preparation method of N-methylpyrrolidone.

Background

Microchannel technology has gained increasing attention from the 90 s of the world after being formally proposed in the european and american countries, and becomes a leading edge and hot spot direction of chemical disciplines. In the field of industrial application, the micro-reactor technology is highly valued by countries and enterprises, the core objective is to develop novel process strengthening equipment, establish novel chemical plants which are miniaturized, modularized, continuous and intelligent, realize safer, more environment-friendly, more efficient and more economical production modes, and show that the micro-reactor technology can be successfully applied to actual industrial production through research on a plurality of industrial projects covering the fields of medicine, chemical intermediates and polymers, and has obvious advantages in various aspects such as yield, production capacity, space-time yield, equipment investment, operation cost, environmental influence and the like compared with the traditional reaction equipment.

In recent years, along with the requirements of safety, environmental protection and cost reduction, the micro-chemical technology is applied to medicines, dyes and certain bulk chemicals, but because the flow pattern and mass transfer behavior in a micro-reactor are completely different from those in the traditional reaction, a plurality of heterogeneous reaction processes with complex process exist in the fine chemical industry, and the production processes of a plurality of high-added-value fine chemical products comprise various processes such as heat transfer, mixing, reaction, separation and even external field strengthening, although the accurate regulation and control on the production process of the products can be realized in a micro-channel reactor, the traditional continuous flow synthesis technology does not have very mature commercial products and process routes in the aspect of heterogeneous system multi-process coupling.

US6248902 continuous non-catalytic synthesis of N-methylpyrrolidone with gamma-butyrolactone and methylamine at a pressure of 3.0-9.0MPa in a three-stage reaction zone: a) The operation temperature of the first stage reaction section is 150-220 ℃ and the residence time is 5-30 minutes; b) The operation temperature of the second stage reaction section is 220-270 ℃ and the residence time is 1-3 hours; c) The operation temperature of the third stage reaction section is 250-310 ℃ and the residence time is 0.5-2 hours. The synthesis technology has the problems of high reaction temperature, high reaction pressure, long reaction period, high safety risk and the like.

CN107474003 discloses a method for synthesizing N-methylpyrrolidone by continuous flow, which uses a capillary microreactor to intensify the mixing reaction process of gamma-butyrolactone and methylamine, and realizes the efficient continuous synthesis of N-methylpyrrolidone under low pressure, but the process adopts a large amount of ethylene glycol as solvent to avoid the problem of mass transfer resistance in the gas-liquid mixing process, and the subsequent process increases energy consumption in the separation process for realizing the recycling of the solvent, so the technology has a limited degree of improvement compared with the traditional process in terms of process energy efficiency.

Disclosure of Invention

The invention aims to solve the problems of high reaction temperature, high reaction pressure, long reaction period, high safety risk and increased energy consumption caused by subsequent separation and recovery of solvents in the synthesis of N-methylpyrrolidone in the prior art, and provides a microchannel reaction device and a preparation method of N-methylpyrrolidone.

In order to achieve the above object, the present invention provides in one aspect a microchannel reactor comprising a mixer having a liquid phase feed inlet and a reactor in sealed communication with the mixer, the reactor being provided with a product outlet;

the mixer comprises a liquid phase fluid channel communicated with the liquid phase feed inlet, wherein the periphery of the liquid phase fluid channel sequentially surrounds a plurality of layers of microscale sleeves without gaps, the periphery of the microscale sleeve at the outermost layer surrounds a mixer shell with at least one gas phase feed inlet with gaps, a plurality of through holes are formed in the wall of each layer of microscale sleeve, the through holes of each layer are staggered by an angle, so that each layer of through holes are overlapped to form a gradually-reduced gas phase channel, and gas phase raw materials entering the mixer shell through each gas phase feed inlet are gradually contracted to form microbubbles, and enter the liquid phase fluid channel to be dissolved and mixed with the liquid phase raw materials to form a homogeneous solution;

the reactor comprises a reactor shell, wherein a plurality of groups of grid plate microscale components are arranged in the reactor shell in parallel with the material flow direction without gaps, each group of grid plate microscale components are formed by oppositely overlapping two identical grid plate microscale plug-ins, each grid plate microscale plug-in is provided with a plurality of parallel slits along the material flow direction, and the slits of the adjacent two grid plate microscale plug-ins are staggered by an angle, so that homogeneous solution from the mixer only passes through the overlapping parts of the slits of the adjacent two grid plate microscale plug-ins to form a tortuous reaction fluid path, and the reaction materials are fully homogenized and reacted.

The second aspect of the invention provides a method for preparing N-methyl pyrrolidone, which is implemented by the microchannel reaction device of the invention, comprising the following steps:

1) The gas phase raw material entering through the gas phase feed inlet is dispersed into micro bubbles through a plurality of layers of the micro-scale sleeves, and is mixed with the liquid phase raw material entering through the liquid phase feed inlet in the liquid phase fluid channel, so that a homogeneous phase solution is obtained under the mixing condition, and the homogeneous phase solution is fed into the reactor;

2) The homogeneous solution in the step 1) flows and reacts among slits of a plurality of grid plate microscale plug-ins in a reactor, so that the contact efficiency between the gas phase raw material and a liquid phase reaction system is enhanced, and a target product is obtained under the reaction condition;

wherein the gas phase feed comprises one or more of methylamine, dimethylamine and trimethylamine, and the liquid phase feed comprises gamma-butyrolactone.

According to the technical scheme, the solvent is not adopted, no post-separation treatment unit is adopted, and a mixer comprising a core component and a multi-layer overlapped microscale sleeve with a through hole is adopted, so that the solubility is increased, the reaction pressure is reduced, and the micro-channel reaction device provided by the invention effectively strengthens the gas-liquid dispersion performance in a multiphase flow system by utilizing a microscale effect, so that the gas-phase raw material can be efficiently dissolved in the liquid-phase raw material, and a high-efficiency, safe and continuous reaction process is realized.

The invention controls the temperature and pressure of the mixing process and the reaction process and the gas-liquid ratio condition respectively, matches the mixing dissolution rate of the reaction system and the reaction progress of the reaction, effectively limits the heat release amount of the reaction process, ensures the gas-liquid mixing efficiency under a certain gas-liquid ratio, has better applicability for heterogeneous reaction systems with high heat effect and high air-liquid ratio, can be used for continuous processes of various different gas-liquid reaction systems, does not need to introduce extra solvent to increase the energy consumption of a subsequent separation section, and has more obvious effect especially for the process of synthesizing N-methylpyrrolidone.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

FIG. 1 is a schematic view of a microchannel reactor according to a preferred embodiment of the invention;

FIG. 2 is a schematic view of a mixer according to a preferred embodiment of the present invention;

FIG. 3 is a schematic view of a reactor structure according to a preferred embodiment of the present invention.

Description of the reference numerals

1 a liquid phase feed inlet; 2 a gas phase feed inlet; 3 a mixer; a 4 reactor; 5, a product outlet; 6, mixing the shell; 7 a porous microscale sleeve; 8 liquid phase fluid channels; 9 a reactor shell; 10 grid microscale plugins; 11 slits; 12 through holes.

Detailed Description

The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

In the present invention, unless otherwise specified, terms such as "upper, lower, left, and right" and "upper, lower, left, and right" are used generically to refer to the upper, lower, left, and right illustrated in the drawings; "inside and outside" refer to the inside and outside of the profile of each component itself, the hydraulic diameter in the present invention refers to four times the ratio of the area of the flow cross section to the perimeter, and is commonly used in the calculation of the resistance of pipes in chemical equipment, the equivalent diameter refers to the non-circular pipe diameter, which can be replaced by a circular pipe diameter, defined as: 4. Cross-sectional area of conduit/wetted perimeter.

As shown in fig. 1 to 3, a first aspect of the present invention provides a microchannel reactor apparatus comprising a mixer 3 having a liquid phase feed inlet 1 and a reactor 4 in sealed communication with the mixer 3, the reactor 4 being provided with a product outlet 5;

the mixer 3 comprises a liquid phase fluid channel 8 communicated with the liquid phase feed inlet 1; the periphery of the liquid phase fluid channel 8 is sequentially wrapped with a plurality of layers of microscale sleeves 7 without gaps, the periphery of the microscale sleeve 7 at the outermost layer is wrapped with a mixer shell 6 with at least one gas phase feed port 2 with gaps, a plurality of through holes 12 are formed in the wall of each layer of microscale sleeve 7, the through holes 12 of each layer are staggered by an angle, so that each layer of through holes 12 are overlapped to form a gradually-reduced gas phase channel, and gas phase raw materials entering the mixer shell 6 through each gas phase feed port 2 are gradually reduced to form microbubbles, and enter the liquid phase fluid channel 8 to be dissolved and mixed with the liquid phase raw materials to form a homogeneous solution;

the reactor 4 comprises a reactor shell 9, a plurality of groups of grid plate microscale components are arranged in the reactor shell 9 in parallel with the material flow direction without gaps, each group of grid plate microscale components is formed by overlapping two identical grid plate microscale plug-ins 10 in opposite directions, each grid plate microscale plug-in 10 is provided with a plurality of parallel slits 11 along the material flow direction, and the slits 11 of the adjacent two grid plate microscale plug-ins 10 are staggered by an angle, so that homogeneous solution from the mixer 3 only passes through the overlapping parts of the slits 11 of the adjacent two grid plate microscale plug-ins 10 to form a tortuous reaction fluid path, and the reaction materials are fully homogenized and reacted.

The prior art is adopted in the invention to seal the relevant interfaces of the mixer and the reactor to form a micro-channel, various pipelines or valves and parts possibly needed in industry can be added according to the needs, and the invention has no special requirements for the aspects, and is not described in detail herein.

Specifically, as shown in fig. 1-2, the liquid-phase raw material enters the liquid-phase fluid channel 8 through the liquid-phase feed inlet 1, the gas-phase raw material enters the mixer shell 6 through at least one gas-phase feed inlet 2, preferably two gas-phase feed inlets 2, and flows through the gas-phase raw material channel formed by the through holes on the multi-layer micro-scale sleeve 7 which is nested inside and outside to be dispersed into tiny bubbles, enters the liquid-phase fluid channel to be dissolved and mixed with the liquid-phase raw material to form a homogeneous solution, and then flows into the reactor 4 to react; in a preferred embodiment of the invention, the through holes on the two adjacent layers of microscale bushings 7 are processed into relative staggered angles, so that the through holes between the two adjacent layers are not completely overlapped when in installation, and the overlapping of the through holes 12 with multiple staggered angles gradually reduces the integral overlapping part between the through holes, so that a gas phase raw material channel is formed, and the purpose of gradually dispersing gas phase raw materials into tiny bubbles is achieved; by improving the dispersion degree of the gas phase raw material, the contact area of the gas phase and the liquid phase is increased, the mass transfer resistance is reduced, and the safety risk is reduced; of course, in another preferred embodiment of the present invention, the through holes of each layer of the microscale sleeve 7 can be overlapped to ensure that the size of each layer of through holes 12 is reduced from the outer layer to the inner layer.

In the present invention, the reactor shell is in gapless fit with the edges of each grid microscale insert 10 therein, and two adjacent grid microscale inserts 10 (here, two grid microscale inserts are identical, and are in a split-oriented distinction pattern of 10a and 10b as shown in fig. 3 for convenience of understanding) are overlapped in opposite directions to form a grid microscale assembly, so that the homogeneous solution from the mixer 3 only passes through the overlapped portions of the slits 11 of two adjacent grid microscale inserts 10 to form a tortuous reaction fluid path, and finally the whole reactor is filled, so that the reaction materials are fully homogenized and reacted.

The device is particularly suitable for gas-liquid two-phase contact reaction with the molar ratio of gas phase to liquid phase being more than 5.

According to a preferred embodiment of the invention, the mixer housing 6 has an equivalent diameter of 5-12cm, preferably 6-10cm, and a length of 10-20cm, preferably 12-16cm.

According to a preferred embodiment of the invention, the number of layers of the microscale sleeve 7 in the mixer 3 is 5-20, preferably 8-12.

According to a preferred embodiment of the present invention, the microscale sleeve 7 is preferably a cylindrical ring, more preferably the microscale sleeve 7 has a thickness of 4-12mm, even more preferably 4-8mm.

According to a preferred embodiment of the invention, the hydraulic diameter of the liquid phase fluid channel 8 is 200-800 μm, preferably 400-600 μm, and the length of the liquid phase fluid channel 8 is the same as the length of the mixer housing 6. It should be noted that, a filter membrane is disposed in the liquid-phase fluid channel 8, and the filter membrane allows gas to pass therethrough but does not allow liquid to pass therethrough, which is a prior art well known to those skilled in the art, and the present invention is not described in detail herein.

According to a preferred embodiment of the invention, the open porosity on the wall of the microscale sleeve 7 is 30-90%, preferably 60-80%.

According to a preferred embodiment of the invention, the through holes 12 of each layer are preferably offset by an angle of 5-10 °, more preferably 6-8 °.

According to a preferred embodiment of the present invention, the through hole 12 is a racetrack-shaped hole formed by semicircular sides of a middle rectangle.

According to a preferred embodiment of the present invention, the through hole 12 preferably has a long axis of 20-200 μm, more preferably 60-120 μm.

According to a preferred embodiment of the present invention, the short axis of the through hole 12 is preferably 10-80 μm, more preferably 20-40 μm.

According to a preferred embodiment of the invention, the reactor shell 9 has an equivalent diameter of 5-12cm, preferably 6-10cm, and a length of 20-40cm, preferably 24-32cm.

According to a preferred embodiment of the present invention, the number of layers of the louver micro-scale insert 10 is 50-200, preferably 70-90.

As shown in fig. 3, according to a preferred embodiment of the present invention, the louver micro-scale insert 10 is preferably a rectangular sheet, and more preferably the louver micro-scale insert 10 has a thickness of 0.4 to 1mm, and still more preferably 0.4 to 0.8mm.

According to a preferred embodiment of the present invention, said slits 11 provided in each of said grid microscale inserts 10 consist of two identical parallelogram holes, one end of which is close to each other but not communicating, and the other end is distant from each other.

According to a preferred embodiment of the present invention, the slits of two adjacent grid microscale inserts 10 are preferably offset by an angle of 5-10 °, more preferably 6-8 °, and likewise the slits of two adjacent layers are offset by an angle during processing.

According to a preferred embodiment of the present invention, preferably, two adjacent slits 11 on the louver micro-scale insert 10 are spaced apart by 5-50 μm, preferably 10-30 μm.

According to a preferred embodiment of the invention, the slit 11 preferably has a length of 1-8cm, more preferably 2-6cm;

according to a preferred embodiment of the invention, preferably each of said parallelogram shaped holes has a width of 5-50 μm, more preferably 10-30 μm; preferably, the parallelogram shaped holes have an inclination angle, more preferably an inclination angle of 10-80 °, even more preferably 15-45 °.

According to a preferred embodiment of the invention, the liquid phase feed inlet 1 and the gas phase feed inlet 2 have the same hydraulic diameter, preferably both have a hydraulic diameter of 1000-3000 μm, more preferably 1500-2000 μm.

According to a preferred embodiment of the present invention, preferably, the extension line of each gas phase feed inlet 2 forms an angle with the extension line of the liquid phase feed inlet 1, more preferably an angle of 15-90 °, still more preferably 30-60 °.

According to a preferred embodiment of the invention, the product outlet 5 has a hydraulic diameter of 200-800 μm, preferably 400-600 μm.

According to a preferred embodiment of the invention, the materials of the liquid feed inlet 1, the gas phase feed inlet 2, the mixer 3, the reactor 4 and the product outlet 5 are selected from one or more of metals, alloys and ceramics, preferably from one or more of stainless steel 316L, hastelloy C and silicon carbide ceramics.

1) The gas phase raw material entering through the gas phase feed inlet 2 flows through a plurality of layers of the microscale sleeves 7 to be dispersed into micro bubbles, and the micro bubbles are mixed with the liquid phase raw material entering through the liquid phase feed inlet 1 in the liquid phase fluid channel 8, so that a homogeneous phase solution is obtained under the mixing condition, and the homogeneous phase solution is sent into the reactor 4;

2) The homogeneous solution in the step 1) flows and reacts among the slits of a plurality of grid plate microscale plug-ins 10 in a reactor 4, so as to strengthen the contact efficiency between the gas-phase raw material and a liquid-phase reaction system, and obtain a target product under the reaction condition;

In the prior art, the problem of re-separation treatment exists in the follow-up process by solvent dissolution, but the invention does not adopt solvent and has no post-separation treatment unit. The mixer 3 comprising a core component, namely a multi-layer overlapped microscale sleeve 7 with through holes is adopted to disperse the gas phase raw material into tiny bubbles, and the contact area of the gas phase and the liquid phase is increased by improving the dispersion degree of the gas phase raw material, so that the solubility is increased, and the reaction pressure is reduced.

The method is particularly suitable for gas-liquid two-phase contact reaction with the molar ratio of gas phase to liquid phase being more than 5.

According to a preferred embodiment of the invention, the mixing conditions comprise: the mixing temperature is 10-50deg.C, the mixing pressure is 1-3MPa, and the residence time is 1-10min.

According to a preferred embodiment of the present invention, the reaction conditions include: the reaction temperature is 200-350 ℃, the reaction pressure is 2-4MPa, and the residence time is 10-30min.

The present invention is further illustrated by the following examples and comparative examples, but the apparatus and method of the present invention are not limited thereto.

The apparatus and method of the present invention are further described below in conjunction with the examples.

Example 1

(1) The device construction was performed as shown in fig. 1-3:

the micro-channel reaction device body is formed by processing stainless steel 316L, a micro-scale structure is manufactured on a stainless steel substrate through precision machining, a micro-scale sleeve 7 and a grid plate micro-scale plug-in 10 are respectively overlapped in a concentric ring and alternate plug-in plate mode in a mixer 3 and a reactor 4, a liquid phase fluid channel 8 of the mixer is formed after relevant interfaces are sealed, and specific arrangement and dimensions are as follows: the hydraulic diameter of the liquid phase feed inlet 1 is 1000 mu m, the hydraulic diameter of the gas phase feed inlet 2 is 1000 mu m, and the included angle between the two is 30 degrees; the hydraulic diameter of the product outlet 5 is 800 μm; the equivalent diameter of the mixer housing 6 is 10cm, the length is 20cm, and the hydraulic diameter of the liquid phase fluid channel is 500 μm; the thickness of the microscale sleeve is 4mm, the number of layers is 10, the long axis of the through hole 12 is 120 mu m, the short axis is 60 mu m, the aperture ratio is 75%, and the positioning stagger angle between each layer is 8 degrees; the equivalent diameter of the reactor shell 9 is 10cm and the length is 40cm; the thickness of the grid plate microscale plug-in 10 is 0.8mm, and the number of layers is 100; the slit interval of the grid microscale insert was 20 μm, the slit length was 3cm, the width of each parallelogram hole constituting the slit 11 was 30 μm, the parallelogram hole tilt angle was 30 °, and the misalignment angle between each layer of slits was 8 °.

The micro-channel reaction device built by referring to the device shown in fig. 1 is used for synthesizing N-methyl pyrrolidone, the temperature of different modules of the micro-reactor is controlled by an independent cold and hot integrated machine, and the crude N-methyl pyrrolidone can be collected from a product outlet.

(2) 2N-methyl pyrrolidone synthesis: a metering pump is used for conveying liquid-phase raw materials, the raw materials are gamma-butyrolactone, and the gamma-butyrolactone enters a mixer 3 from a liquid-phase feed inlet 1; the gas phase raw material methylamine is conveyed by a mass flowmeter and enters the mixer from two gas phase feed inlets 2 in equal quantity. The molar flow ratio of the main raw materials in the metering pump and the mass flowmeter is set as methylamine: gamma-butyrolactone=1.2:1. The three materials are fully contacted in the mixer 3 and then enter the reactor 4 for condensation reaction, the temperature of the mixer is controlled to be 20 ℃, the pressure is controlled to be 2.0MPa, the temperature of the reactor is controlled to be 240 ℃, the reaction pressure is controlled to be 1.0MPa, the mixing residence time of the reaction materials is controlled to be 5min by adjusting the flow of the metering pump and the mass flowmeter, and the reaction residence time is controlled to be 25min. The material at the outlet 5 of the final liquid-phase product of the micro-channel reaction device is the crude product of N-methyl pyrrolidone. The product analysis results show that the conversion rate of gamma-butyrolactone is 95.3%, and the selectivity of N-methylpyrrolidone is 99.4%.

Example 2

All steps in this example are substantially identical to those in example 1, except that the hydraulic diameter of the liquid phase flow channel 8 in this example is 1000. Mu.m, the thickness of the microscale sleeve 7 is 3.75mm, the number of layers is 10, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 92.1% and the selectivity of N-methylpyrrolidone is 99.6%.

Example 3

All the steps in this example are substantially identical to those in example 1, except that the hydraulic diameter of the liquid phase flow channel 8 in this example is 200. Mu.m, the thickness of the microscale sleeve is 4.25mm, the number of layers is 10, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 95.9% and the selectivity of N-methylpyrrolidone is 98.8%.

Example 4

All the steps in this example are substantially identical to those in example 1, except that the major axis of the through-hole 12 in this example is 200. Mu.m, the minor axis is 100. Mu.m, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 89.1% and the selectivity to N-methylpyrrolidone is 99.3%.

Example 5

All the steps in this example are substantially identical to those in example 1, except that the major axis of the through-hole 12 in this example is 80. Mu.m, the minor axis is 40. Mu.m, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 96.1% and the selectivity to N-methylpyrrolidone is 98.4%.

Example 6

All steps in this example are substantially identical to those in example 1, except that the thickness of the grid microscale insert 10 in this example is 1.0mm, the number of layers is 80, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 85.1% and the selectivity to N-methylpyrrolidone is 99.6%.

Example 7

All steps in this example are substantially identical to those in example 1, except that the thickness of the grid microscale insert 10 in this example is 0.4mm, the number of layers is 200, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 96.6% and the selectivity to N-methylpyrrolidone is 98.3%.

Example 8

All the steps in this example are substantially identical to those in example 1, except that the slit spacing of the grid microscale insert 10 in this example is 40 μm, the width of each parallelogram hole is 60 μm, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 81.9% and the selectivity to N-methylpyrrolidone is 99.4%.

Example 9

All the steps in this example are substantially identical to those in example 1, except that the slit spacing of the grid microscale insert 10 in this example is 10 μm, the width of each parallelogram hole is 20 μm, and the results of product analysis indicate that the conversion of gamma-butyrolactone during the reaction is 95.9% and the selectivity to N-methylpyrrolidone is 98.5%.

Example 10

All the steps in this example were substantially identical to those in example 1, except that the temperature of the reactor in this example was 280℃and the results of the product analysis showed that the conversion of gamma-butyrolactone during the reaction was 98.9% and the selectivity to N-methylpyrrolidone was 91.4%.

Example 11

All the steps in this example were substantially identical to those in example 1, except that the temperature of the reactor in this example was 200℃and the results of the product analysis showed 93.2% conversion of gamma-butyrolactone and 99.8% selectivity to N-methylpyrrolidone during the reaction.

Example 12

All the steps in this example were substantially identical to those in example 1, except that the pressure of the reactor in this example was 2.0MPa, and the results of product analysis showed that the conversion of gamma-butyrolactone during the reaction was 96.2% and the selectivity to N-methylpyrrolidone was 99.0%.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a plurality of simple variants of the technical proposal of the invention can be carried out, comprising that each specific technical feature is combined in any suitable way, and the invention does not need to be additionally described for each possible combination way. Such simple variations and combinations are likewise to be regarded as being within the scope of the present disclosure.

Claims

1. A microchannel reactor characterized in that the device comprises a mixer (3) with a liquid phase feed inlet (1) and a reactor (4) in sealed communication with the mixer (3), the reactor (4) being provided with a product outlet (5);

the mixer (3) comprises a liquid phase fluid channel (8) communicated with the liquid phase feed inlet (1), wherein the periphery of the liquid phase fluid channel (8) sequentially surrounds a plurality of layers of microscale sleeves (7) without gaps, the periphery of the microscale sleeve (7) at the outermost layer surrounds a mixer shell (6) with at least one gas phase feed inlet (2) with gaps, a plurality of through holes (12) are formed in the wall of each layer of microscale sleeve (7), the through holes (12) are staggered in an angle, so that each layer of through holes (12) are overlapped to form a gradually-reduced gas phase channel, and gas phase raw materials entering the mixer shell (6) through each gas phase feed inlet (2) are gradually reduced to form microbubbles, and enter the liquid phase fluid channel (8) to be dissolved and mixed with the liquid phase raw materials to form a homogeneous solution;

the reactor (4) comprises a reactor shell (9), a plurality of groups of grid plate microscale components are arranged in the reactor shell (9) in parallel with the material flow direction without gaps, each group of grid plate microscale components are formed by oppositely overlapping two identical grid plate microscale plug-ins (10), a plurality of parallel slits (11) are arranged on each grid plate microscale plug-in (10) along the material flow direction, the angles of staggering between the slits (11) of the adjacent two grid plate microscale plug-ins (10) are arranged, so that homogeneous solution from the mixer (3) only passes through the overlapping parts of the slits (11) of the adjacent two grid plate microscale plug-ins (10) to form a tortuous reaction fluid path, and the reaction materials are fully homogenized and reacted.

2. The reaction device according to claim 1, wherein the equivalent diameter of the mixer housing (6) is 5-12cm, preferably 6-10cm; the length is 10-20cm; and/or

The number of layers of the microscale sleeve (7) in the mixer (3) is 5-20, preferably 8-12;

preferably, the microscale sleeve (7) is a cylindrical ring, more preferably the microscale sleeve (7) has a thickness of 4-12mm, even more preferably 4-8mm; and/or

The hydraulic diameter of the liquid phase fluid channel (8) is 200-800 μm, preferably 400-600 μm, and the length of the liquid phase fluid channel (8) is the same as the length of the mixer housing (6).

3. The reaction device according to claim 1 or 2, wherein the open porosity on the wall of the microscale sleeve (7) is 30-90%, preferably 60-80%;

preferably, the through holes (12) of each layer are staggered by an angle of 5-10 degrees, more preferably 6-8 degrees; and/or

The through hole (12) is a runway-shaped hole with semicircular middle rectangle two sides;

preferably, the through hole (12) has a long axis of 20-200 μm, more preferably 60-120 μm;

preferably, the through hole (12) has a short axis of 10-80 μm, more preferably 20-40 μm.

4. A reaction device according to any one of claims 1-3, wherein the reactor shell (9) has an equivalent diameter of 5-12cm, preferably 6-10cm, a length of 20-40cm, preferably 24-32cm; and/or

The number of layers of the grid plate microscale plug-in (10) is 50-200, preferably 70-90;

preferably, the louver micro-scale insert (10) is a rectangular sheet, more preferably the louver micro-scale insert (10) has a thickness of 0.4-1mm, still more preferably 0.4-0.8mm.

5. The reaction device according to any one of claims 1 to 4, wherein said slits (11) provided in each of said grid microscale inserts (10) consist of two identical parallelogram holes, one end of which is close to but not communicating with each other and the other end of which is distant from each other;

preferably, the offset angle between the slits of two adjacent grid microscale inserts (10) is 5-10 °, more preferably 6-8 °;

preferably, two adjacent slits (11) on the grid microscale insert (10) are spaced 5-50 μm apart, preferably 10-30 μm apart;

preferably, the slit (11) has a length of 1-8cm, more preferably 2-6cm;

preferably, each of said parallelogram shaped apertures has a width of 5-50 μm, more preferably 10-30 μm;

preferably, the parallelogram shaped holes have an inclination angle, more preferably an inclination angle of 10-80 °, even more preferably 15-45 °.

6. The reaction device according to any one of claims 1 to 5, wherein the liquid phase feed inlet (1) and the gas phase feed inlet (2) have the same hydraulic diameter, preferably both hydraulic diameters of 1000-3000 μm, more preferably 1500-2000 μm;

preferably, the extension line of each gas phase feed inlet (2) forms an included angle with the extension line of the liquid phase feed inlet (1), more preferably the included angle is 15-90 °, still more preferably 30-60 °.

7. A reaction device according to any one of claims 1-6, wherein the product outlet (5) has a hydraulic diameter of 200-800 μm, preferably 400-600 μm.

8. The reaction device according to any one of claims 1-7, wherein the material of the liquid feed inlet (1), the gas phase feed inlet (2), the mixer (3), the reactor (4) and the product outlet (5) is selected from one or more of metals, alloys and ceramics, preferably from one or more of stainless steel 316L, hastelloy C and silicon carbide ceramics.

9. A process for the preparation of N-methylpyrrolidone, characterized in that it is carried out by a microchannel reaction apparatus according to any one of claims 1 to 8, comprising the following steps:

1) The gas phase raw material entering through the gas phase feed inlet (2) flows through a plurality of layers of micro-scale sleeves (7) to be dispersed into micro-bubbles, the micro-bubbles are mixed with the liquid phase raw material entering through the liquid phase feed inlet (1) in the liquid phase fluid channel (8), a homogeneous phase solution is obtained under the mixing condition, and the homogeneous phase solution is fed into the reactor (4);

2) The homogeneous solution in the step 1) flows and reacts among slits of a plurality of grid plate microscale plug-ins (10) in a reactor (4), so that the contact efficiency between a gas-phase raw material and a liquid-phase reaction system is enhanced, and a target product is obtained under the reaction condition;

10. The method of claim 9, wherein,

the conditions of mixing include: the mixing temperature is 10-50 ℃, the mixing pressure is 1-3MPa, and the residence time is 1-10min; and/or

The reaction conditions include: the reaction temperature is 200-350 ℃, the reaction pressure is 2-4MPa, and the residence time is 10-30min.