Method for continuously synthesizing epsilon-caprolactone

Abstract

The invention relates to the field of organic synthesis, and discloses a method for continuously synthesizing epsilon-caprolactone. The method comprises the following steps: respectively injecting cyclohexanone and an oxidant into a micro-channel reaction device for oxidation rearrangement reaction; wherein the micro-channel reaction device comprises a first chip and second chips located on the two sides of the first chip, micro-scale grooves are formed in the first chip and the second chips, the micro-scale grooves are combined together to form one or more micro-channels which are connected in series or in parallel, and each micro-channel is of a three-dimensional streaming structure. According to the process method provided by the invention, based on the micro-channel reaction device, the flow channel pressure, the mixing index and the graded feeding ratio of the cyclohexanone oxidation rearrangement reaction system are accurately controlled, the continuous production of epsilon-caprolactone is realized, and the process conversion efficiency is obviously improved.

Description

Technical Field

[0001] The invention relates to the field of organic synthesis, and in particular to a method for continuously synthesizing epsilon-caprolactone. Background Art

[0002] Microchannel process intensification technology can achieve higher heat and mass transfer efficiency. At the same time, the small effective volume of the reactor can ensure the intrinsic safety of the process, and can accurately control the material ratio, reaction temperature and residence time, etc., which is expected to effectively inhibit the occurrence of side reactions in complex organic synthesis processes and improve the yield and purity of target products. Its continuous operation mode can improve the controllability of the production process and the stability of product quality; through quantitative amplification, it can improve production capacity and realize on-demand production, and can quickly respond to market demand for rapid amplification.

[0003] At present, although many companies have carried out the research and development and production of ε-caprolactone, most of them remain in the pilot stage and have not yet achieved industrialization. Although it is reported that many ε-caprolactone production facilities in China have opened up the process and produced qualified products, no domestic ε-caprolactone is found on the market. Domestic downstream users also have the intention to launch ε-caprolactone production lines, but due to the high safety risks, long reaction time, and cumbersome operation of traditional methods, they have not been implemented. This shows the difficulty of producing ε-caprolactone products.

[0004] Chinese patent application CN 103539770A discloses a microchannel reaction technology for preparing ε-caprolactone based on the oxidation of cyclohexanone with peracetic acid. Chinese patent application CN106279093 A discloses a microchannel reaction technology for preparing ε-caprolactone based on the oxidation of cyclohexanone with meta-chloroperbenzoic acid. The above two processes achieve efficient mixing and reaction of heterogeneous systems, but there are no targeted measures for controlling the impurity content, which affects the selectivity of the final product and increases the subsequent separation cost, which is difficult to scale up in production. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of low selectivity, great production difficulty and high cost in the production process of ε-caprolactone, and to provide a method for continuously synthesizing ε-caprolactone.

[0006] In order to achieve the above object, the present invention provides a method for continuously synthesizing ε-caprolactone, the method comprising: injecting cyclohexanone and an oxidant into a microchannel reaction device respectively to carry out an oxidative rearrangement reaction;

[0007] Among them, the microchannel reaction device includes a first chip and a second chip located on both sides of the first chip, and microscale grooves are formed on the first chip and the second chip. These microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure.

[0008] Preferably, the oxidant is injected in a multi-stage manner;

[0009] Preferably, the oxidant is injected in 2-20 stages, more preferably in 3-6 stages;

[0010] Preferably, the amount injected in each stage accounts for 1-75 wt% of the total amount; more preferably, 20-40 wt%. Preferably, the oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide.

[0011] Preferably, the conditions for the oxidative rearrangement reaction include: a pressure of 100-5000 kPa, preferably 1000-3000 kPa; a temperature of 50-120°C, preferably 85-105°C.

[0012] Preferably, the tube resistance of the microchannel is 0.01-1.0 kPa / m, more preferably 0.05-0.5 kPa / m.

[0013] Preferably, the mixing index of cyclohexanone and the oxidant in the microchannel is ≥ 0.8, preferably ≥ 0.9, more preferably ≥ 0.95.

[0014] Preferably, the microchannel comprises a plurality of mixing units, each mixing unit has a plurality of micro-sized flow paths, each of the micro-sized flow paths has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different.

[0015] Preferably, a transition module is provided between two adjacent mixing units, and each of the micro-sized flow paths in the mixing unit is communicated with the transition module.

[0016] Preferably, the mixing unit in the microchannel has at least two structures, and the structures of two adjacent mixing units on the same microchannel are different.

[0017] Preferably, the first structural form of the mixing unit in the microchannel is: having 4 micro-sized flow paths, which are arranged in three layers from top to bottom, with an upper layer having 1 micro-sized flow path, a middle layer having 2 micro-sized flow paths, and a lower layer having 1 micro-sized flow path;

[0018] Preferably, the gap between the upper layer and the middle layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm;

[0019] Preferably, the gap between the middle layer and the lower layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm.

[0020] Preferably, in the mixing unit of the first structural form, each micro-sized flow path has 3 modules.

[0021] Preferably, on the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and right-angle trapezoid respectively;

[0022] In the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angled trapezoid, rectangle and isosceles trapezoid respectively.

[0023] Preferably, the second structural form of the mixing unit in the microchannel is: having 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer;

[0024] Preferably, the gap between the upper layer and the middle layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm;

[0025] Preferably, the gap between the middle layer and the lower layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm.

[0026] Preferably, in the mixing unit of the second structural form, each micro-sized flow path has 3 modules.

[0027] Preferably, on the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angled trapezoid, rectangle and right-angled trapezoid respectively;

[0028] In the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and isosceles trapezoid respectively.

[0029] Preferably, an inlet module is provided at the feed end of at least one of the microchannels, and the inlet module has three inlets arranged from top to bottom;

[0030] Preferably, the inlet module is connected to the subsequent mixing unit via a transition module.

[0031] Preferably, two adjacent microchannels are connected via a connecting module.

[0032] Preferably, the oxidant is injected in a multi-stage manner, the first-stage oxidant is injected through the upper inlet and the lower inlet of the inlet module, and the remaining oxidant is injected through the connecting module.

[0033] Preferably, the length of a single microchannel is 6-60 cm, preferably 10-48 cm, more preferably 24-36 cm;

[0034] Preferably, the total length of the microchannel is 0.1-10 m, preferably 1-5 m, more preferably 2-3 m.

[0035] Preferably, an outlet module is provided at the discharge end of at least one of the microchannels.

[0036] Preferably, the material of the first chip and the second chip is respectively selected from at least one of borosilicate glass, stainless steel, silicon carbide and polytetrafluoroethylene, and the sealing material between the first chip and the second chip is selected from at least one of polytetrafluoroethylene, EPDM rubber, perfluororubber and graphite.

[0037] The process method provided by the present invention realizes precise control of the flow channel pressure, mixing index and graded feed ratio of the cyclohexanone oxidation rearrangement reaction system based on a microchannel reaction device, realizes the continuous production of ε-caprolactone and significantly improves the process conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of the three-dimensional structure of a microchannel in a microchannel reaction device according to an embodiment of the present invention;

[0039] Figure 2 is a top view of a microchannel in a microchannel reaction device according to an embodiment of the present invention;

[0040] Figure 3 is a side view of a microchannel in a microchannel reaction device according to an embodiment of the present invention;

[0041] Figure 4 Schematic diagram of the structure of a microchannel reaction device according to an embodiment of the present invention.

[0042] Description of Reference Numerals

[0043] a, entrance module; b, transition module; c-first mixing unit; d-second mixing unit; e, connection module. DETAILED DESCRIPTION

[0044] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0045] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0046] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, unless otherwise specified, features defined as "first" and "second" may explicitly or implicitly include one or more of the features; "plurality" means two or more. The term "including" and any variation thereof means non-exclusive inclusion, and one or more other features, integers, steps, operations, units, components and / or combinations thereof may exist or be added.

[0047] In addition, terms indicating orientation or positional relationships such as "upper", "lower", "inside", and "outside" are described based on the orientation or relative positional relationships shown in the drawings, and are only for the convenience of describing the simplified description of the present application, and do not indicate that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0048] In addition, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internally connected between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0049] The present invention discloses a method for continuously synthesizing ε-caprolactone, which comprises: injecting cyclohexanone and an oxidant into a microchannel reaction device respectively to carry out an oxidative rearrangement reaction;

[0050] Among them, combined with reference Figure 1-4 The microchannel reaction device includes a first chip and a second chip located on both sides of the first chip. Microscale grooves are formed on the first chip and the second chip. These microscale grooves are combined to form one or more microchannels connected in series or in parallel. The microchannel has a three-dimensional flow structure.

[0051] The microchannel reaction device of the present invention is a plate-type microchannel reaction device, wherein the microchannel reaction device forms a plurality of microchannels by combining the microscale grooves in the first chip and the second chip, and the pressure and mixing index of the reaction system can be effectively controlled by using the three-dimensional flow structure in the microchannel, thereby achieving efficient mixing of cyclohexanone and the oxidant. In the present invention, the microscale grooves on the first chip and the second chip can be formed by high-precision machining or etching process.

[0052] In a preferred embodiment, the oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide.

[0053] In a preferred embodiment, the conditions of the oxidative rearrangement reaction include: a pressure of 100-5000 kPa, preferably 1000-3000 kPa; a temperature of 50-120° C., preferably 85-105° C. In a specific embodiment, the temperature of the oxidative rearrangement reaction may be 85° C., 90° C., 95° C., 100° C. or 105° C.; and the pressure of the oxidative rearrangement reaction may be 1000 kPa, 1500 kPa, 2000 kPa, 2500 kPa or 3000 kPa.

[0054] In a preferred embodiment, the tube resistance of the microchannel is 0.01-1.0 kPa / m, more preferably 0.05-0.5 kPa / m.

[0055] In the plate-type microchannel reaction device of the present invention, the total length of the microchannel can be 0.1-10m, preferably 1-5m, and more preferably 2-3m; the number of the microchannels can be 3-30, preferably 5-20; the length of a single microchannel can be 6-60cm, preferably 10-48cm, and more preferably 24-36cm; the liquid holding capacity of the plate-type microchannel reaction device can be 10-50mL, preferably 16-30mL.

[0056] In the method of the present invention, injecting cyclohexanone and oxidant into the above-mentioned microchannel reaction device for reaction is conducive to promoting the mixing of cyclohexanone and oxidant. In a preferred embodiment, the mixing index of cyclohexanone and oxidant in the microchannel is ≥0.8, preferably ≥0.9, and more preferably ≥0.95.

[0057] In the present invention, the mixing index is calculated by the following formula,

[0058]

[0059] Where N represents the value of N different points of the detection outlet, C i Indicates the component concentration value at each point in the channel outlet cross section, in mol / m 3 , It represents the average value of the component concentration at the channel outlet, in mol / m 3 .

[0060] In a preferred embodiment, the microchannel includes a plurality of mixing units, each of which has a plurality of micro-sized flow paths, each of which has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different. In each of the micro-sized flow paths, through the combination of modules of different shapes and / or sizes, the reaction raw materials entering each micro-sized flow path of the mixing unit change their flow direction and flow rate between each module, thereby achieving efficient mixing.

[0061] Further preferably, a transition module b is provided between two adjacent mixing units, and each of the micro-sized flow paths in the mixing unit is communicated with the transition module b.

[0062] More preferably, the mixing unit in the microchannel has at least two structures, and the structures of two adjacent mixing units in the same microchannel are different. Through this structural arrangement, the reaction raw materials are mixed in two adjacent mixing units in different mixing modes, thereby promoting uniform mixing of the reaction raw materials, and further promoting the reaction efficiency of cyclohexanone and the oxidant.

[0063] In some embodiments, the first structural form of the mixing unit in the microchannel (i.e., the first mixing unit c) is: having 4 micro-sized flow paths, which are arranged in three layers from top to bottom, with 1 micro-sized flow path in the upper layer, 2 micro-sized flow paths in the middle layer, and 1 micro-sized flow path in the lower layer. Specifically, the gap between the upper layer and the middle layer is 20-1000 μm, preferably 50-500 μm, and more preferably 100-200 μm; the gap between the middle layer and the lower layer is 20-1000 μm, preferably 50-500 μm, and more preferably 100-200 μm. Further, in the mixing unit of the first structural form, each micro-sized flow path has 3 modules. Furthermore, on the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and right trapezoid respectively; on the micro-sized flow paths of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right trapezoid, rectangle and isosceles trapezoid respectively. Specifically, the base angle of the isosceles trapezoidal module is 15-75°, the base length is 0.5-5mm, the top length is 0.1-2mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the base angle of the right-angled trapezoidal module is 15-75°, the base length is 0.2-2.5mm, the top length is 0.1-1mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the length of the rectangular parallelepiped module is 0.1-2mm, the width is 0.1-2mm, and the depth is 0.5-3mm; and the angle between adjacent faces of adjacent modules is 5-20°.

[0064] In other embodiments, the second structural form of the mixing unit in the microchannel (i.e., the second mixing unit d) is: having 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer. Specifically, the gap between the upper layer and the middle layer is 20-1000μm, preferably 50-500μm, and more preferably 100-200μm; the gap between the middle layer and the lower layer is 20-1000μm, preferably 50-500μm, and more preferably 100-200μm. Further, in the mixing unit of the second structural form, each micro-sized flow path has 3 modules. Furthermore, on the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are respectively a right-angled trapezoid, a rectangle and a right-angled trapezoid; on the micro-sized flow paths of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are respectively an isosceles trapezoid, a rectangle and an isosceles trapezoid. Specifically, the base angle of the isosceles trapezoidal module is 15-75°, the base length is 0.5-5mm, the top length is 0.1-2mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the base angle of the right-angled trapezoidal module is 15-75°, the base length is 0.2-2.5mm, the top length is 0.1-1mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the length of the rectangular parallelepiped module is 0.1-2mm, the width is 0.1-2mm, and the depth is 0.5-3mm; and the angle between adjacent faces of adjacent modules is 5-20°.

[0065] According to a preferred embodiment of the present invention, the microchannel has a plurality of the first mixing units c and a plurality of the second mixing units d, and along the flow direction of the logistics, the next mixing unit of each of the first mixing units c is the second mixing unit d, and the next mixing unit of each of the second mixing units d is the first mixing unit c, and the adjacent first mixing units c and second mixing units d are connected through the transition module b.

[0066] In the microchannel reaction device of the present invention, an inlet module a is provided at the feed end of at least one of the microchannels, and the inlet module a has three inlets arranged from top to bottom, the upper inlet and the lower inlet can be used as the oxidant inlet, and the middle inlet can be used as the cyclohexanone inlet. Further preferably, the size of each inlet includes: length of 0.5-5mm, width of 0.1-2mm, and depth of 2-10mm.

[0067] According to a preferred embodiment of the present invention, the inlet module a is connected to the subsequent mixing unit through the transition module b. With this structural arrangement, the raw materials injected through the inlet module a are first preliminarily mixed in the transition module b, and then divided and injected into each micro-sized flow path of the subsequent mixing unit for further circumferential mixing.

[0068] In a specific implementation, the dimensions of the transition module b include: 0.5-5 mm in length, 0.5-5 mm in width, and 1-4 mm in depth.

[0069] In a preferred embodiment, two adjacent microchannels are connected via a connecting module e. Further preferably, at least one of the connecting modules e is provided with a grading inlet, and the grading inlet can be used to inject an oxidant.

[0070] In a specific implementation, the dimensions of the connection module e include: 0.5-8 mm in length, 1-10 mm in width, and 2-4 mm in depth.

[0071] In a preferred embodiment, the oxidant is injected in a multi-stage manner; further preferably, the oxidant is injected in a 2-20-stage manner, more preferably in a 3-6-stage manner.

[0072] In a preferred embodiment, the amount injected in each stage accounts for 1-75 wt% of the total amount; more preferably, 20-40 wt%.

[0073] Injecting the oxidant into the microchannel reaction device in a multi-stage injection manner, i.e., through multiple inlets, can promote uniform mixing of the reaction raw materials, thereby promoting the reaction efficiency of cyclohexanone and the oxidant. In a preferred embodiment, the first-stage oxidant can be injected through the upper inlet and the lower inlet of the inlet module a, and the remaining oxidant can be injected through the graded inlet provided on the connection module e.

[0074] In a specific embodiment, the oxidant is injected in a five-stage manner, wherein the first-stage oxidant is injected through the upper and lower inlets of the inlet module a, and the second to fifth-stage oxidants are respectively injected through the graded inlets of the four connecting modules e.

[0075] In a preferred embodiment, an outlet module is provided at the discharge end of at least one of the microchannels, and the dimensions of the outlet module include: 0.5-5 mm in length, 0.5-5 mm in width, and 4-10 mm in depth.

[0076] In a preferred embodiment, the material of the first chip and the second chip is respectively selected from at least one of borosilicate glass, stainless steel, silicon carbide and polytetrafluoroethylene.

[0077] In a preferred embodiment, the sealing material between the first chip and the second chip is selected from at least one of polytetrafluoroethylene, EPDM rubber, perfluororubber and graphite.

[0078] According to some embodiments of the present invention, a method for continuously synthesizing ε-caprolactone includes: injecting cyclohexanone and an oxidant into a microchannel reaction device according to a stoichiometric ratio to perform an oxidative rearrangement reaction;

[0079] The microchannel reaction device comprises a first chip and a second chip located on both sides of the first chip, wherein the first chip and the second chip are both formed with microscale grooves, and the microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure;

[0080] Specifically, the microchannel includes a plurality of mixing units, each mixing unit has a plurality of micro-sized flow paths, each of the micro-sized flow paths has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different; a transition module b is provided between two adjacent mixing units, and each of the micro-sized flow paths in the mixing unit is connected to the transition module b; an inlet module a is provided at the feed end of at least one of the microchannels, and the inlet module a is connected to the subsequent mixing unit through the transition module b; two adjacent microchannels are connected through a connection module e, and an outlet module is provided at the discharge end of at least one of the microchannels;

[0081] The conditions for the oxidative rearrangement reaction include: pressure of 100-5000 kPa; temperature of 50-120°C;

[0082] The oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide.

[0083] According to some embodiments of the present invention, the method for continuously synthesizing ε-caprolactone comprises:

[0084] (1) filling the entire microchannel reaction device with a solvent as an inert medium and raising the reaction environment in the microchannel reaction device to the temperature and pressure of the oxidative rearrangement reaction, wherein the inert medium circulates between the units and controls the flow rate to the flow rate required for the reaction through a mass flow meter;

[0085] (2) injecting cyclohexanone and an oxidant into a microchannel reaction device according to a stoichiometric ratio to carry out an oxidative rearrangement reaction;

[0086] The microchannel reaction device comprises a first chip and a second chip located on both sides of the first chip, wherein the first chip and the second chip are both formed with microscale grooves, and the microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure;

[0087] Specifically, the microchannel includes a plurality of mixing units, each mixing unit has a plurality of micro-sized flow paths, each of the micro-sized flow paths has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different; a transition module b is provided between two adjacent mixing units, and each of the micro-sized flow paths in the mixing unit is connected to the transition module b; an inlet module a is provided at the feed end of at least one of the microchannels, and the inlet module a is connected to the subsequent mixing unit through the transition module b; two adjacent microchannels are connected through a connection module e, and an outlet module is provided at the discharge end of at least one of the microchannels;

[0088] The pressure of the oxidative rearrangement reaction is 100-5000 kPa and the temperature is 50-120°C;

[0089] The tube resistance of the microchannel is 0.01-1.0 kPa / m;

[0090] The mixing index of cyclohexanone and oxidant in the microchannel is ≥ 0.8;

[0091] The oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide;

[0092] Cyclohexanone is injected into the microchannel reaction device from the inlet module a, and the oxidant is injected into the microchannel reaction device in a multi-stage injection manner. The first-stage oxidant is injected through the inlet module a, and the remaining oxidant is injected through the connecting module e. The reacted material is discharged through the outlet module.

[0093] According to some embodiments of the present invention, the method for continuously synthesizing ε-caprolactone comprises:

[0094] (1) filling the entire microchannel reaction device with a solvent as an inert medium and raising the reaction environment in the microchannel reaction device to the temperature and pressure of the oxidative rearrangement reaction, wherein the inert medium circulates between the units and controls the flow rate to the required flow rate for the reaction through a mass flow meter; wherein the solvent is selected from one or more of acetone, ethyl acetate, ethyl propionate and propionic acid;

[0095] (2) injecting cyclohexanone and an oxidant into a microchannel reaction device according to a stoichiometric ratio to carry out an oxidative rearrangement reaction;

[0096] The microchannel reaction device comprises a first chip and a second chip located on both sides of the first chip, wherein the first chip and the second chip are both formed with microscale grooves, and the microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure;

[0097] Specifically, the microchannel includes a plurality of mixing units, each mixing unit has a plurality of micro-sized flow paths, each of the micro-sized flow paths has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different; the microchannel has a plurality of the first mixing units c and a plurality of the second mixing units d, and along the flow direction of the logistics, the next mixing unit of each of the first mixing units c is the second mixing unit d, and the next mixing unit of each of the second mixing units d is the first mixing unit c, and the adjacent first mixing units c and second mixing units d are connected through the transition module b, wherein the first mixing unit c has 4 micro-sized flow paths, and these micro-sized flow paths are arranged in three layers from top to bottom, with an upper layer of 1 micro-sized flow path, a middle layer of 2 micro-sized flow paths, and a lower layer of 1 micro-sized flow path. The invention relates to a mixing unit d having 5 micro-sized flow paths, each of which has 3 modules; the gap between the upper layer and the middle layer is 20-1000 μm, and the gap between the middle layer and the lower layer is 20-1000 μm; the second mixing unit d has 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer, and each micro-sized flow path has 3 modules; the gap between the upper layer and the middle layer is 20-1000 μm, and the gap between the middle layer and the lower layer is 20-1000 μm; an inlet module a is provided at the feed end of at least one of the microchannels, and the inlet module a is connected to the subsequent mixing unit through the transition module b; two adjacent microchannels are connected through a connecting module e, and an outlet module is provided at the discharge end of at least one of the microchannels;

[0098] The pressure of the oxidative rearrangement reaction is 100-5000 kPa and the temperature is 50-120°C;

[0099] The tube resistance of the microchannel is 0.01-1.0 kPa / m;

[0100] The mixing index of cyclohexanone and oxidant in the microchannel is ≥ 0.8;

[0101] The oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide;

[0102] Cyclohexanone is injected into the microchannel reaction device from the inlet module a, and the oxidant is injected into the microchannel reaction device in a multi-stage injection manner. The first-stage oxidant is injected through the inlet module a, and the remaining oxidant is injected through the connecting module e. The reacted material is discharged through the outlet module.

[0103] According to some embodiments of the present invention, the method for continuously synthesizing ε-caprolactone comprises:

[0104] (1) filling the entire microchannel reaction device with a solvent as an inert medium and raising the reaction environment in the microchannel reaction device to the temperature and pressure of the oxidative rearrangement reaction, wherein the inert medium circulates between the units and controls the flow rate to the required flow rate for the reaction through a mass flow meter; wherein the solvent is selected from one or more of acetone, ethyl acetate, ethyl propionate and propionic acid;

[0105] (2) injecting cyclohexanone and an oxidant into a microchannel reaction device according to a stoichiometric ratio to carry out an oxidative rearrangement reaction;

[0106] The microchannel reaction device comprises a first chip and a second chip located on both sides of the first chip, wherein the first chip and the second chip are both formed with microscale grooves, and the microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure;

[0107] Specifically, the microchannel includes a plurality of mixing units, each mixing unit has a plurality of micro-sized flow paths, each of the micro-sized flow paths has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different; the microchannel has a plurality of the first mixing units c and a plurality of the second mixing units d, along the flow direction of the logistics, the next mixing unit of each of the first mixing units c is the second mixing unit d, and the next mixing unit of each of the second mixing units d is the first mixing unit c, and the first mixing units c and the second mixing units d adjacent to each other are connected. The first mixing unit c is connected through the transition module b, wherein the first mixing unit c has 4 micro-sized flow paths, which are arranged in three layers from top to bottom, with 1 micro-sized flow path in the upper layer, 2 micro-sized flow paths in the middle layer, and 1 micro-sized flow path in the lower layer, and each micro-sized flow path has 3 modules, the gap between the upper layer and the middle layer is 20-1000 μm, and the gap between the middle layer and the lower layer is 20-1000 μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and right-angle trapezoid in turn; the micro-sized flow paths in the middle layer are arranged in three layers, and the gap between the upper and middle layers is 20-1000 μm, and the gap between the middle layer and the lower layer is 20-1000 μm. The main cross-sectional shapes of the three modules along the flow direction of the logistics are a right-angled trapezoid, a rectangle and an isosceles trapezoid respectively; the second mixing unit d has 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer, and each micro-sized flow path has 3 modules, the gap between the upper layer and the middle layer is 20-1000μm, and the gap between the middle layer and the lower layer is 20-1000μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are a right-angled trapezoid, a rectangle and an isosceles trapezoid respectively; the second mixing unit d has 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer, and each micro-sized flow path has 3 modules, the gap between the upper layer and the middle layer is 20-1000μm, and the gap between the middle layer and the lower layer is 20-1000μm. The cross-sectional shapes are right-angled trapezoid, rectangle and right-angled trapezoid in sequence; on the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and isosceles trapezoid in sequence; an inlet module a is provided at the feed end of at least one of the microchannels, and the inlet module a has three inlets arranged from top to bottom; the inlet module a is connected to the subsequent mixing unit through the transition module b; two adjacent microchannels are connected through a connecting module e, and at least one of the connecting modules e is provided with a graded inlet; an outlet module is provided at the discharge end of at least one of the microchannels;

[0108] The pressure of the oxidative rearrangement reaction is 100-5000 kPa and the temperature is 50-120°C;

[0109] The tube resistance of the microchannel is 0.01-1.0 kPa / m;

[0110] The mixing index of cyclohexanone and oxidant in the microchannel is ≥ 0.8;

[0111] The oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide;

[0112] Cyclohexanone is injected into the microchannel reaction device from the middle inlet of the inlet module a, and the oxidant is injected into the microchannel reaction device in a multi-stage injection manner, with the number of stages being 2-20; the amount injected in each stage accounts for 1-75 weight % of the total amount; wherein the first stage oxidant is injected through the upper inlet and the lower inlet of the inlet module a, and the remaining oxidant is injected through the graded inlet of the connecting module e, and the reacted material is discharged through the outlet module.

[0113] According to some embodiments of the present invention, the method for continuously synthesizing ε-caprolactone comprises:

[0114] (1) filling the entire microchannel reaction device with a solvent as an inert medium and raising the reaction environment in the microchannel reaction device to the temperature and pressure of the oxidative rearrangement reaction, wherein the inert medium circulates between the units and controls the flow rate to the required flow rate for the reaction through a mass flow meter; wherein the solvent is selected from one or more of acetone, ethyl acetate, ethyl propionate and propionic acid;

[0115] (2) injecting cyclohexanone and an oxidant into a microchannel reaction device according to a stoichiometric ratio to carry out an oxidative rearrangement reaction;

[0116] The microchannel reaction device comprises a first chip and a second chip located on both sides of the first chip, wherein the first chip and the second chip are both formed with microscale grooves, and the microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure;

[0117] Specifically, the microchannel includes a plurality of mixing units, each mixing unit has a plurality of micro-sized flow paths, each of the micro-sized flow paths has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different; the microchannel has a plurality of the first mixing units c and a plurality of the second mixing units d, along the flow direction of the logistics, the next mixing unit of each of the first mixing units c is the second mixing unit d, and the next mixing unit of each of the second mixing units d is the first mixing unit c, and the adjacent first mixing units c and second mixing units d are connected through the transition module b, wherein the first mixing unit c has 4 micro-sized flow paths, and these micro-sized flow paths are arranged in three layers from top to bottom The upper layer is 1 micro-sized flow path, the middle layer is 2 micro-sized flow paths, and the lower layer is 1 micro-sized flow path, and each micro-sized flow path has 3 modules, the gap between the upper layer and the middle layer is 20-1000μm, and the gap between the middle layer and the lower layer is 20-1000μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and right-angled trapezoid, respectively. On the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angled trapezoid, rectangle and isosceles trapezoid, respectively, among which the bottom side angle of the isosceles trapezoidal module is 15-75°, the bottom side length is 0.5-5mm, the top side length is 0.1-2mm, and the height is 0.5-3mm , the depth is 0.5-3mm; the bottom angle of the right-angle trapezoidal module is 15-75°, the bottom length is 0.2-2.5mm, the top length is 0.1-1mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the length of the rectangular parallelepiped module is 0.1-2mm, the width is 0.1-2mm, the depth is 0.5-3mm, and the angle between adjacent faces of each adjacent module is 5-20°; the second mixing unit d has 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer, and each micro-sized flow path has 3 modules, the gap between the upper layer and the middle layer is 20-1000μm, and the middle The gap between the upper and lower layers is 20-1000μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angled trapezoid, rectangle and right-angled trapezoid, respectively. On the micro-sized flow paths of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and isosceles trapezoid, respectively. Among them, the bottom angle of the isosceles trapezoidal module is 15-75°, the bottom length is 0.5-5mm, the top length is 0.1-2mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the bottom angle of the right-angled trapezoidal module is 15-75°, the bottom length is 0.2-2.5mm, the top length is 0.1-1mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the length of the rectangular parallelepiped module is 0.1-2mm, the width is 0.1-2mm, the depth is 0.5-3mm, and the angle between adjacent faces of each adjacent module is 5-20°; an inlet module a is provided at the feed end of at least one of the microchannels, the inlet module a has three inlets arranged from top to bottom, and the dimensions of each inlet include: a length of 0.5-5mm, a width of 0.1-2mm, and a depth of 2-10mm; the inlet module a is connected to the subsequent mixing unit through the transition module b; the dimensions of the transition module b include: a length of 0.5-5mm, a width of 0.5-5 mm, and a depth of 2-4 mm; two adjacent microchannels are connected by a connecting module e, and the dimensions of the connecting module e include: length 0.5-5 mm, width 1-10 mm, and depth 2-4 mm; at least one connecting module e is provided with a graded inlet; an outlet module is provided at the discharge end of at least one of the microchannels, and the dimensions of the outlet module include: length 0.5-5 mm, width 0.5-5 mm, and depth 4-10 mm; the number of the microchannels is 3-30, the length of a single microchannel is 6-60 cm, and the liquid holding capacity of the microchannel reaction device is 10-50 mL;.

[0118] The pressure of the oxidative rearrangement reaction is 100-5000 kPa and the temperature is 50-120°C;

[0119] The tube resistance of the microchannel is 0.01-1.0 kPa / m;

[0120] The mixing index of cyclohexanone and oxidant in the microchannel is ≥ 0.8;

[0121] The oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide;

[0122] Cyclohexanone is injected into the microchannel reaction device from the middle inlet of the inlet module a, and the oxidant is injected into the microchannel reaction device in a multi-stage injection manner, with the number of stages being 2-20; the amount injected in each stage accounts for 1-75 weight % of the total amount; wherein the first stage oxidant is injected through the upper inlet and the lower inlet of the inlet module a, and the remaining oxidant is injected through the graded inlet of the connecting module e, and the reacted material is discharged through the outlet module.

[0123] According to some embodiments of the present invention, the method for continuously synthesizing ε-caprolactone comprises:

[0124] (1) filling the entire microchannel reaction device with a solvent as an inert medium and raising the reaction environment in the microchannel reaction device to the temperature and pressure of the oxidative rearrangement reaction, wherein the inert medium circulates between the units and controls the flow rate to the required flow rate for the reaction through a mass flow meter; wherein the solvent is selected from one or more of acetone, ethyl acetate, ethyl propionate and propionic acid;

[0125] (2) injecting cyclohexanone and an oxidant into a microchannel reaction device according to a stoichiometric ratio to carry out an oxidative rearrangement reaction;

[0126] The microchannel reaction device comprises a first chip and a second chip located on both sides of the first chip, wherein the first chip and the second chip are both formed with microscale grooves, and the microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure;

[0127] Specifically, the microchannel includes a plurality of first mixing units c and a plurality of second mixing units d. Along the flow direction of the logistics, the next mixing unit of each first mixing unit c is the second mixing unit d, and the next mixing unit of each second mixing unit d is the first mixing unit c, and the adjacent first mixing units c and second mixing units d are connected through the transition module b, wherein the first mixing unit c has 4 micro-sized flow paths, and these micro-sized flow paths are arranged in three layers from top to bottom, the upper layer is 1 micro-sized flow path, the middle layer is 2 micro-sized flow paths, and the lower layer is 1 micro-sized flow path, and each micro-sized flow path has 3 modules, and the gap between the upper layer and the middle layer The diameter of the gap between the middle layer and the lower layer is 20-1000μm, and the gap between the middle layer and the lower layer is 20-1000μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and right-angle trapezoid, respectively. On the micro-sized flow paths of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angle trapezoid, rectangle and isosceles trapezoid, respectively. Among them, the bottom angle of the isosceles trapezoidal module is 15-75°, the bottom length is 0.5-5mm, the top length is 0.1-2mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the bottom angle of the right-angle trapezoidal module is 15-75°, the bottom length is 0.2-2.5mm, the top length is 0 .1-1mm, 0.5-3mm high, 0.5-3mm deep; the length of the rectangular module is 0.1-2mm, the width is 0.1-2mm, the depth is 0.5-3mm, and the angle between adjacent faces of each adjacent module is 5-20°; the second mixing unit d has 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer, and each micro-sized flow path has 3 modules, the gap between the upper layer and the middle layer is 20-1000μm, and the gap between the middle layer and the lower layer is 20-1000μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, 3 The main cross-sectional shapes of the modules are right-angled trapezoid, rectangle and right-angled trapezoid, respectively. On the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and isosceles trapezoid, respectively. Among them, the bottom angle of the isosceles trapezoidal module is 15-75°, the bottom length is 0.5-5mm, the top length is 0.1-2mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the bottom angle of the right-angled trapezoidal module is 15-75°, the bottom length is 0.2-2.5mm, the top length is 0.1-1mm, the height is 0.5-3mm, and the depth is 0.5-3mm; the length of the rectangular module is 0.1-2mm, the width is 0.1-2mm, and the depth is 0.5-3mm, and the angle between adjacent faces of each adjacent module is 5-20°; an inlet module a is provided at the feed end of at least one of the microchannels, and the inlet module a has three inlets arranged from top to bottom, and the dimensions of each inlet include: length 0.5-5mm, width 0.1-2mm, depth 2-10mm; the inlet module a is connected to the subsequent mixing unit through the transition module b; the dimensions of the transition module b include: length 0.5-5mm, width 0.5-5mm, depth 2-4mm; two adjacent microchannels are connected through a connecting module e, and the dimensions of the connecting module e include: length 0.5-5mm, width 1-10mm, depth 2-4mm; to At least one connection module e is provided with a graded inlet; an outlet module is provided at the discharge end of at least one of the microchannels, and the dimensions of the outlet module include: length 0.5-5mm, width 0.5-5mm, depth 4-10mm; the number of the microchannels is 3-30, the length of a single microchannel is 6-60cm, the total length of the microchannels is 0.1-10m, and the liquid holding capacity of the microchannel reaction device is 10-50mL; the material of the first chip and the second chip is each selected from at least one of borosilicate glass, stainless steel, silicon carbide and polytetrafluoroethylene, and the sealing material between the first chip and the second chip is selected from at least one of polytetrafluoroethylene, EPDM rubber, perfluororubber and graphite;.

[0128] The pressure of the oxidative rearrangement reaction is 100-5000 kPa and the temperature is 50-120°C;

[0129] The tube resistance of the microchannel is 0.01-1.0 kPa / m;

[0130] The mixing index of cyclohexanone and oxidant in the microchannel is ≥ 0.8;

[0131] The oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide;

[0132] Cyclohexanone is injected into the microchannel reaction device from the middle inlet of the inlet module a, and the oxidant is injected into the microchannel reaction device in a multi-stage injection manner, with the number of stages being 2-20; the amount injected in each stage accounts for 1-75 weight % of the total amount; wherein the first-stage oxidant is injected through the upper inlet and the lower inlet of the inlet module a, and the remaining stages of oxidant are injected through the graded inlets of the connecting module e, and the reacted materials are discharged through the outlet module.

[0133] The plate-type microchannel reaction device and its application described in the present invention are further described below by way of examples. The examples are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0134] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0135] Example 1

[0136] (1) Construction of microchannel reaction device

[0137] like Figure 1-4 As shown, the microchannel reaction device includes a first chip and a second chip located on both sides of the first chip (that is, the first chip and the second chip are arranged alternately), microscale grooves are formed on the first chip and the second chip, and these microscale grooves are combined to form 20 microchannels connected in series, and the microchannel has a three-dimensional flow structure; the length of a single microchannel is 10 cm, the total length is 2 m, and the liquid holding capacity is 16 mL; the material of the first chip and the second chip is borosilicate glass, and the sealing material between the first chip and the second chip is perfluororubber;

[0138] Specifically, the microchannel includes a plurality of first mixing units c and a plurality of second mixing units d, and along the flow direction of the logistics, the next mixing unit of each first mixing unit c is the second mixing unit d, and the next mixing unit of each second mixing unit d is the first mixing unit c, and the adjacent first mixing units c and second mixing units d are connected through the transition module b, wherein the first mixing unit c has 4 micro-sized flow paths, and these micro-sized flow paths are arranged in three layers from top to bottom, with an upper layer of 1 micro-sized flow path, a middle layer of 2 micro-sized flow paths, and a lower layer of 1 micro-sized flow path. The micro-sized flow path is provided with 3 modules, the gap between the upper layer and the middle layer is 150 μm, and the gap between the middle layer and the lower layer is 150 μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the 3 modules are isosceles trapezoid, rectangle and right-angle trapezoid, respectively. On the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the 3 modules are right-angle trapezoid, rectangle and isosceles trapezoid, respectively. Among them, the bottom angle of the isosceles trapezoidal module is 45°, the bottom length is 3 mm, the top length is 1 mm, the height is 1 mm, and the depth is 1 mm; the bottom of the right-angle trapezoidal module is 1 mm long, the top length is 1 mm, the height is 1 mm, and the depth is 1 mm. The side angle is 45°, the bottom side length is 1mm, the top side length is 0.5mm, the height is 1mm, and the depth is 1mm; the length of the rectangular module is 1mm, the width is 0.5mm, the depth is 1mm, and the angle between adjacent faces of each adjacent module is 15°; the second mixing unit d has 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer, and each micro-sized flow path has 3 modules, the gap between the upper layer and the middle layer is 150μm, the gap between the middle layer and the lower layer is 150μm, and the gap between the upper layer and the middle layer is 150μm. On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angled trapezoid, rectangle and right-angled trapezoid, respectively. On the micro-sized flow paths of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and isosceles trapezoid, respectively. Among them, the bottom angle of the isosceles trapezoid module is 45°, the bottom length is 3mm, the top length is 1mm, the height is 1mm, and the depth is 1mm; the bottom angle of the right-angled trapezoid module is 45°, the bottom length is 1mm, the top length is 0.5mm, the height is 1mm, and the depth is 1mm; the length of the rectangular module is 1mm, the width is 0.5mm, 1mm in depth, and the angle between adjacent faces of each adjacent module is 15°; an inlet module a is provided at the feed end of the outer microchannel, the inlet module a has three inlets arranged from top to bottom, and the dimensions of each inlet include: length 3mm, width 2 / 3mm, depth 5mm; the inlet module a is connected to the subsequent mixing unit through the transition module b; the dimensions of the transition module b include: length 3mm, width 2m, depth 1mm; two adjacent microchannels are connected through a connecting module e, the dimensions of the connecting module e include: length 6mm, width 2mm, depth 2mm; among them, 4 connecting modules e are provided with graded inlets; an outlet module is provided at the discharge end of another outer microchannel (the side opposite to the inlet module), the dimensions of the outlet module include: length 3mm, width 2mm, depth 5mm;.

[0139] The outside of the microchannel reaction device is heated by a circulating oil bath;

[0140] (2) Synthesis of caprolactone

[0141] The entire microchannel reaction device is filled with propionic acid as an inert medium and the reaction environment in the microchannel reaction device is raised to 95° C. and 1.5 MPa, and the inert medium circulates between the units and controls the flow rate to the required flow rate for the reaction through a mass flow meter;

[0142] Cyclohexanone and 20% peroxy propionic acid solution enter the microchannel reaction device through the middle inlet and the upper and lower inlets of the inlet module a at equal volume flow rates, mix and react, and the remaining peroxy propionic acid solution is divided into 4 equal parts and injected through the graded inlets of the 4 connection modules e. The tube resistance of the microchannel during the reaction is controlled to be 0.1 kPa / m; the mixing index of cyclohexanone and the oxidant in the microchannel is 0.95; the reacted materials are discharged through the outlet module. According to gas chromatography analysis, the cyclohexanone conversion rate during the reaction process is 99.5%, the caprolactone selectivity is 99.9%, and the peroxy acid utilization rate is 95.4%.

[0143] Comparative Example 1

[0144] The microchannel reactor with a microporous nozzle provided in patent application CN201811248554.8 was used to synthesize caprolactone. The cyclohexanone oxidation rearrangement reaction process was carried out under the same conditions as in Example 1 (i.e., the same raw materials, reaction temperature and pressure were used). The composition of the materials after the reaction was analyzed by gas chromatography, and it was obtained that the cyclohexanone conversion rate of the reaction process was 80.1%, the caprolactone selectivity was 96.2%, and the peroxyacid utilization rate was 88.9%.

[0145] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for continuously synthesizing ε-caprolactone, characterized in that: The method comprises: injecting cyclohexanone and an oxidant into a microchannel reaction device respectively to carry out an oxidative rearrangement reaction; Among them, the microchannel reaction device includes a first chip and a second chip located on both sides of the first chip, and microscale grooves are formed on the first chip and the second chip. These microscale grooves are combined to form one or more microchannels connected in series or in parallel, and the microchannel has a three-dimensional flow structure.

2. The method according to claim 1, characterized in that The injection method of the oxidant is multi-stage injection; Preferably, the oxidant is injected in 2-20 stages, more preferably in 3-6 stages; Preferably, the amount injected in each stage accounts for 1-75 wt% of the total amount; more preferably, 20-40 wt%.

3. The method according to claim 1, characterized in that The oxidant is selected from one or more of hydrogen peroxide, peracetic acid, peroxypropionic acid and cumene hydroperoxide.

4. The method according to claim 1, characterized in that The conditions for the oxidative rearrangement reaction include: a pressure of 100-5000 kPa, preferably 1000-3000 kPa; a temperature of 50-120°C, preferably 85-105°C.

5. The method according to claim 1 or 4, characterized in that: The tube resistance of the microchannel is 0.01-1.0 kPa / m, more preferably 0.05-0.5 kPa / m.

6. The method according to claim 1, characterized in that The mixing index of cyclohexanone and the oxidant in the microchannel is ≥0.8, preferably ≥0.9, and more preferably ≥0.

95.

7. The method according to claim 1, characterized in that The microchannel includes a plurality of mixing units, each mixing unit has a plurality of micro-sized flow paths, each of the micro-sized flow paths has a plurality of modules, and the shapes and / or sizes of two adjacent modules are different.

8. The method according to claim 6, characterized in that A transition module (b) is provided between two adjacent mixing units, and each of the micro-sized flow paths in the mixing unit is communicated with the transition module (b).

9. The method according to claim 1, characterized in that: The mixing unit in the microchannel has at least two structures, and the structures of two adjacent mixing units on the same microchannel are different.

10. The method according to claim 9, characterized in that The first structural form of the mixing unit in the microchannel is: having 4 micro-sized flow paths, which are arranged in three layers from top to bottom, with an upper layer having 1 micro-sized flow path, a middle layer having 2 micro-sized flow paths, and a lower layer having 1 micro-sized flow path; Preferably, the gap between the upper layer and the middle layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm; Preferably, the gap between the middle layer and the lower layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm.

11. The method according to claim 10, characterized in that In the mixing unit of the first structural form, each micro-sized flow path has three modules.

12. The method according to claim 11, characterized in that On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and right-angle trapezoid respectively; In the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angled trapezoid, rectangle and isosceles trapezoid respectively.

13. The method according to claim 9, characterized in that The second structural form of the mixing unit in the microchannel is: having 5 micro-sized flow paths, which are arranged in three layers from top to bottom, with 2 micro-sized flow paths in the upper layer, 1 micro-sized flow path in the middle layer, and 2 micro-sized flow paths in the lower layer; Preferably, the gap between the upper layer and the middle layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm; Preferably, the gap between the middle layer and the lower layer is 20-1000 μm, preferably 50-500 μm, more preferably 100-200 μm.

14. The method according to claim 13, characterized in that In the mixing unit of the second structural form, each micro-sized flow path has three modules.

15. The method according to claim 14, characterized in that On the micro-sized flow paths of the upper and lower layers, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are right-angled trapezoid, rectangle and right-angled trapezoid respectively; In the micro-sized flow path of the middle layer, along the flow direction of the logistics, the main cross-sectional shapes of the three modules are isosceles trapezoid, rectangle and isosceles trapezoid respectively.

16. The method according to any one of claims 1 to 15, characterized in that: An inlet module (a) is provided at the feed end of at least one of the microchannels, wherein the inlet module (a) has three inlets arranged from top to bottom; Preferably, the inlet module (a) is connected to the subsequent mixing unit via a transition module (b).

17. The method according to claim 1 or 16, characterized in that Two adjacent microchannels are connected via a connecting module (e).

18. The method according to claim 17, characterized in that The oxidant is injected in a multi-stage manner, wherein the first-stage oxidant is injected through the upper inlet and the lower inlet of the inlet module (a), and the remaining oxidant is injected through the connecting module (e).

19. The method according to claim 1, characterized in that The length of a single microchannel is 6-60 cm, preferably 10-48 cm, more preferably 24-36 cm; Preferably, the total length of the microchannel is 0.1-10 m, preferably 1-5 m, more preferably 2-3 m.

20. The method according to claim 1, characterized in that An outlet module is arranged at the discharge end of at least one of the microchannels.

21. The method according to any one of claims 1 to 20, characterized in that The material of the first chip and the second chip is respectively selected from at least one of borosilicate glass, stainless steel, silicon carbide and polytetrafluoroethylene, and the sealing material between the first chip and the second chip is selected from at least one of polytetrafluoroethylene, EPDM rubber, perfluororubber and graphite.

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