Preparing 5, 5apos; method and device for preparing-oxydimethylene-2-furfural

Abstract

The invention provides a method and device for preparing 5, 5 '-oxydimethylene-2-furfural, and belongs to the technical field of chemical synthesis. The method for preparing the 5, 5 '-oxydimethylene-2-furfural comprises the following steps: mixing 5-hydroxymethylfurfural, a catalyst and an organic solvent in a micro-mixer to obtain a mixture; the mixture is continuously conveyed into a dynamic tubular reactor to be subjected to a self-etherification reaction, a reaction solution containing 5, 5 '-oxydimethylene-2-furfural is obtained, and the inner diameter of the dynamic tubular reactor is 60-80 mm.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method and a device for preparing 5,5'-oxybismethylene-2-furfural. Background Art

[0002] 5,5'-Oxybis(methylene)-2-furfural has a wide range of application prospects. It can not only be used as a monomer for the preparation of certain imine-based polymers, which have good thermal and electrical conductivity, but also can be used to synthesize heterocyclic ligands and hepatitis antiviral precursors.

[0003] In the related art, the method for synthesizing 5,5'-oxybismethylene-2-furfural has the following problems: a kettle reactor is commonly used in industry to synthesize 5,5'-oxybismethylene-2-furfural, which has a long reaction time and low production efficiency; the increase in temperature during the reaction leads to an increase in pressure, which is not safe enough. Summary of the invention

[0004] In view of this, the present invention provides a method and apparatus for preparing 5,5'-oxybismethylene-2-furfural.

[0005] According to an embodiment of one aspect of the present invention, there is provided a method for preparing 5,5'-oxybismethylene-2-furfural, comprising:

[0006] Mixing 5-hydroxymethylfurfural, a catalyst and an organic solvent in a micromixer to obtain a mixture;

[0007] The mixture is continuously transported to a dynamic tubular reactor for self-etherification reaction to obtain a reaction liquid containing 5,5'-oxybismethylene-2-furfural; wherein the inner diameter of the dynamic tubular reactor is 60-80 mm.

[0008] According to an embodiment of the present invention, the micromixer comprises an inlet channel, a first cavity, a plurality of microchannel portions, a second cavity and an outlet channel connected in sequence, wherein the plurality of microchannel portions are arranged in an array in the direction from the first cavity to the second cavity, and a sub-cavity is provided between two adjacent microchannel portions, and the plurality of microchannel portions are used to mix the 5-hydroxymethylfurfural, the catalyst and the organic solvent under microscale conditions.

[0009] According to an embodiment of the present invention, the microchannel portion comprises a plurality of microchannel layers distributed in an array, and the microchannel layer consists of a plurality of groups of V-shaped microchannels distributed in an array.

[0010] According to an embodiment of the present invention, the widths of the microchannels in the plurality of microchannel portions decrease in sequence in a direction from the first cavity to the second cavity.

[0011] According to an embodiment of the present invention, the width of the microchannels in the plurality of microchannel portions is 0.5-0.8 mm.

[0012] According to an embodiment of the present invention, the height of the microchannels in the plurality of microchannel portions is 0.2-0.4 mm.

[0013] According to an embodiment of the present invention, the dynamic tubular reactor comprises a reaction cylinder and a rotating shaft, and the rotating speed of the rotating shaft is 500-800 r / min.

[0014] According to an embodiment of the present invention, the capacity of the reaction cylinder is 50-500 mL.

[0015] According to an embodiment of the present invention, the self-etherification reaction is carried out at 25-165° C., and the dwell time in the dynamic tubular reactor is 1-15 min.

[0016] According to an embodiment of the present invention, the method further comprises: removing water from the reaction liquid containing 5,5'-oxybismethylene-2-furfural through a dehydration membrane to obtain a dehydrated reaction liquid; and transporting the dehydrated reaction liquid to the micromixer through a third liquid phase channel.

[0017] According to an embodiment of the present invention, the mixing of 5-hydroxymethylfurfural, a catalyst and an organic solvent in a micromixer comprises: transporting 5-hydroxymethylfurfural and an organic solvent to the micromixer through a first liquid phase channel, or transporting 5-hydroxymethylfurfural, a catalyst and an organic solvent to the micromixer through a first liquid phase channel; transporting the catalyst and the organic solvent to the micromixer through a second liquid phase channel, or not transporting them.

[0018] According to an embodiment of the present invention, the concentration of the 5-hydroxymethylfurfural is 0.5wt%~15wt%.

[0019] According to an embodiment of the present invention, the catalyst is one or more of p-toluenesulfonic acid, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, phosphomolybdic acid, ferric chloride and ferric sulfate.

[0020] According to an embodiment of the present invention, the concentration of the catalyst is 0.05wt%~1wt%.

[0021] According to an embodiment of the present invention, the organic solvent is one or more of dimethyl carbonate, toluene, acetone, acetonitrile and dichloromethane.

[0022] The present invention also provides a device for preparing 5,5'-oxybismethylene-2-furfural, comprising: a micromixer, suitable for continuously receiving 5-hydroxymethylfurfural, a catalyst and an organic solvent, and mixing them to obtain a mixture; a dynamic tubular reactor, located downstream of the micromixer, suitable for continuously receiving the above mixture from the micromixer, and allowing the mixture to undergo a self-etherification reaction to obtain a reaction liquid containing 5,5'-oxybismethylene-2-furfural, wherein the inner diameter of the dynamic tubular reactor is 60-80 mm.

[0023] According to the embodiments of the present invention, the present invention enhances the mixing effect through a micro mixer, and allows the reaction to reach a temperature and material balance in a short time through the flow system in the dynamic tubular reactor, so that the reaction product can be obtained quickly, the reaction time is shortened, the production efficiency is improved, and the occurrence of side reactions is reduced. In addition, the continuous flow preparation process of the present invention and the relatively small reaction volume of the dynamic tubular reactor avoid the pressure increase caused by the temperature increase in the closed reactor during the reaction process, making the reaction process of the present invention safer.

[0024] The device for preparing 5,5'-oxybismethylene-2-furfural provided by the present invention is relatively simple and easy to build, and is more convenient and safer than a reactor; and the micro-mixer and the dynamic tubular reactor usually adopt a modular design, which can be quickly adjusted and enlarged according to production needs, thereby improving the flexibility and scalability of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The flowchart of the method for preparing 5,5'-oxybismethylene-2-furfural provided in an embodiment of the present invention is schematically shown;

[0026] Figure 2 A cross-sectional view of a micro-mixer provided by an embodiment of the present invention is schematically shown;

[0027] Figure 3 A cross-sectional view of a reaction cylinder of a dynamic tubular reactor provided by an embodiment of the present invention is schematically shown;

[0028] Figure 4 A schematic diagram of a rotating shaft of a dynamic tubular reactor provided by an embodiment of the present invention is schematically shown;

[0029] Figure 5 The device diagram for preparing 5,5'-oxybismethylene-2-furfural provided in an embodiment of the present invention is schematically shown;

[0030] Figure 6 The hydrogen nuclear magnetic resonance spectrum of the crude 5,5'-oxybismethylene-2-furfural provided in Example 1 of the present invention;

[0031] Figure 7 The hydrogen nuclear magnetic resonance spectrum of the pure 5,5'-oxybismethylene-2-furfural provided in Example 1 of the present invention;

[0032] In the above drawings, the meanings of the reference numerals are as follows:

[0033] 1-first liquid phase channel;

[0034] 2-second liquid phase channel;

[0035] 3- first plunger pump;

[0036] 4- Second plunger pump;

[0037] 5- Micro mixer;

[0038] 51-Entranceway;

[0039] 52-first cavity;

[0040] 53-a plurality of microchannel portions;

[0041] 531-first microchannel portion;

[0042] 532-Second microchannel section

[0043] 54- second cavity;

[0044] 55-Exit channel;

[0045] 56-Sub cavity;

[0046] 6- Dynamic tubular reactor;

[0047] 61-reaction cylinder;

[0048] 62-rotation axis;

[0049] 7-Dewatering film;

[0050] 8-quenching device;

[0051] 9-Back pressure valve;

[0052] 10-Analytical equipment. DETAILED DESCRIPTION

[0053] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0054] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0055] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0056] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0057] The present invention provides a method for preparing 5,5'-oxybismethylene-2-furfural based on a dynamic tubular reactor. The experimental methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0058] In the related art, the kettle reactor is used to synthesize 5,5'-oxybis(methylene)-2-furfural, and the reaction time is long, generally 1 to 24 hours, and the production efficiency is low; the temperature increase during the reaction process leads to an increase in pressure, which is not safe enough. In the process of realizing the present invention, it was found that the dynamic tubular reactor can improve production efficiency, output and product consistency through its continuous flow production. In addition, the dynamic tubular reactor can accurately control key parameters such as temperature, pressure and flow rate to optimize the reaction efficiency. At the same time, it provides better safety and stability with efficient heat exchange performance, and the modular design enhances the flexibility and scalability of production. However, with the improvement of production efficiency, there may be problems of incomplete reaction or low yield.

[0059] In the process of implementing the present invention, it was found that the above-mentioned problems of incomplete reaction or low yield may be caused by uneven mixing of the reaction raw materials. The mixing effect of the reaction raw materials can be enhanced by a micro mixer. The use of a micro mixer and a dynamic tubular reactor in combination can shorten the reaction time and improve production efficiency while ensuring the product yield.

[0060] Figure 1 The following is a reaction flow chart for preparing 5,5'-oxybismethylene-2-furfural according to an embodiment of the present invention.

[0061] According to some embodiments of the present invention, the present invention provides a method of 5,5'-oxybismethylene-2-furfural, referring to Figure 1 As shown, steps S110 to S120 are included.

[0062] In step S110, 5-hydroxymethylfurfural, a catalyst and an organic solvent are mixed in a micro mixer to obtain a mixture;

[0063] In step S120, the mixture is continuously transported to a dynamic tubular reactor for self-etherification reaction to obtain a reaction solution containing 5,5'-oxybismethylene-2-furfural; wherein the inner diameter of the dynamic tubular reactor is 60-80 mm.

[0064] According to the embodiments of the present invention, the present invention enhances the mixing effect through a micro mixer, and allows the reaction to reach a temperature and material balance in a short time through the flow system of the dynamic tubular reactor, so that the reaction product can be obtained quickly, the reaction time is shortened, the production efficiency is improved, and the occurrence of side reactions is reduced. In addition, the continuous flow preparation process of the present invention and the relatively small reaction volume of the dynamic tubular reactor avoid the pressure increase caused by the temperature increase in the closed reactor during the reaction process, making the reaction process of the present invention safer.

[0065] According to an embodiment of the present invention, the reaction process for preparing 5,5'-oxybismethylene-2-furfural is as follows:

[0066]

[0067] According to an embodiment of the present invention, the concentration of 5-hydroxymethylfurfural is 0.5wt%~15wt%, preferably 0.5~7.0wt%. Specifically, the concentration of 5-hydroxymethylfurfural can be 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 3.0wt%, 4.0wt%, 5.0wt%, 6.0wt%, 7.0wt%, 7.5wt%, 8.0wt%, 9.0wt%, 10.0wt%, 11.0wt%, 13.0wt% or 15.0wt%, preferably 6.0wt%. In the process of carrying out the relevant experiments of the present invention, it is found that the concentration of suitable 5-hydroxymethylfurfural can have both high production efficiency and product yield.

[0068] According to an embodiment of the present invention, the catalyst is one or more of p-toluenesulfonic acid, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, phosphomolybdic acid, ferric chloride and ferric sulfate, preferably p-toluenesulfonic acid. The concentration of the catalyst is 0.05-1wt%, preferably 0.12-0.24wt%. Specifically, the concentration of the catalyst is 0.05wt%, 0.10wt%, 0.12wt%, 0.16wt%, 0.24wt%, 0.30wt%, 0.40wt%, 0.50wt%, 0.70wt% or 1.00wt%.

[0069] According to an embodiment of the present invention, the organic solvent is one or more of dimethyl carbonate, toluene, acetone, acetonitrile and dichloromethane, preferably acetonitrile.

[0070] According to an embodiment of the present invention, the self-etherification reaction is carried out at 25~165°C, preferably 25~90°C. Specifically, the temperature of the self-etherification reaction can be 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C or 165°C.

[0071] According to an embodiment of the present invention, the dwell time in the dynamic tubular reactor is 1 to 15 min, preferably 1.5 to 10 min. Specifically, the dwell time in the dynamic tubular reactor 6 is 1 min, 1.5 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min or 15 min. Appropriate reaction temperature and time can take into account both production efficiency and yield.

[0072] According to an embodiment of the present invention, water generated in the incompletely reacted solution can be removed by a dehydration membrane, and the reaction solution after dehydration can be subjected to a cyclic reaction. For the obtained reaction solution, the compound can be qualitatively and / or quantitatively analyzed by any one or more analytical equipment such as liquid chromatography, nuclear magnetic resonance hydrogen spectrum, carbon spectrum, etc. In the case where the qualitative and / or quantitative analysis does not meet the product requirements, the reaction solution containing 5,5'-oxybismethylene-2-furfural can be dehydrated by a dehydration membrane to obtain a dehydrated reaction solution; the dehydrated reaction solution is transported to the micromixer through the third liquid phase channel.

[0073] According to an embodiment of the present invention, the reaction solution containing 5,5'-oxybismethylene-2-furfural can also be separated and purified to prepare purified 5,5'-oxybismethylene-2-furfural. Specifically, the purification step can be: filtering the hot reactant while hot, and rotary evaporating the obtained filtrate to obtain a crude 5,5'-oxybismethylene-2-furfural. The crude 5,5'-oxybismethylene-2-furfural is recrystallized from methanol: water = 1:1 (volume ratio) to obtain a pure 5,5'-oxybismethylene-2-furfural.

[0074] The method for preparing 5,5'-oxybismethylene-2-furfural provided by the present invention can be specifically as follows: after the reactor is connected, water, ethanol and an organic solvent are first pumped in to clean the reaction system, and then a reaction substrate solution is pumped in, mixed in a micro mixer, and then purified after reacting for a certain period of time at a certain temperature in a dynamic tubular reactor.

[0075] The present invention also provides a device for preparing 5,5'-oxybismethylene-2-furfural, comprising:

[0076] A micro mixer, adapted to continuously receive 5-hydroxymethylfurfural, a catalyst and an organic solvent, and mix them to obtain a mixture;

[0077] The dynamic tubular reactor is located downstream of the micromixer and is suitable for continuously receiving the mixture from the micromixer and subjecting the mixture to self-etherification reaction to obtain a reaction liquid containing 5,5'-oxybismethylene-2-furfural, wherein the inner diameter of the dynamic tubular reactor is 60-80 mm.

[0078] The device for preparing 5,5'-oxybismethylene-2-furfural provided by the present invention is relatively simple and easy to build, and is more convenient and safer than a reactor; and the micro-mixer and the dynamic tubular reactor usually adopt a modular design, which can be quickly adjusted and enlarged according to production needs, thereby improving the flexibility and scalability of production.

[0079] The present invention does not limit the shape of the micromixer, for example, it can be a cylindrical shape, a cone shape, etc. Specifically, it can be a cylindrical shape, a square cylinder or a rectangular cylinder, etc. To promote the mixing of fluids, the micromixer can adopt a spiral structure, a baffle structure or other geometric structures that can promote fluid turbulence and mixing.

[0080] One preferred solution is Figure 2 As shown, the micro mixer may include an inlet channel 51, a first cavity 52, a plurality of microchannel portions 53, a second cavity 54 and an outlet channel 55 connected in sequence. Among them, the plurality of microchannel portions 53 are arranged in an array in the direction from the first cavity 52 to the second cavity 54, and a sub-cavity 56 is provided between two adjacent microchannel portions. The plurality of microchannel portions 53 are used to mix 5-hydroxymethylfurfural, a catalyst and an organic solvent under microscale conditions, and the microscale conditions may be micrometer or centimeter scale conditions. The sub-cavity 56 is used to mix the 5-hydroxymethylfurfural, a catalyst and an organic solvent flowing out of each microchannel in the microchannel portion. The first cavity 52, the second cavity 54 and the sub-cavity 56 are used to accommodate 5-hydroxymethylfurfural, a catalyst and an organic solvent, and mix the three.

[0081] According to an embodiment of the present invention, the microchannel portion 53 includes a plurality of microchannel layers distributed in an array, and the microchannel layer is composed of a plurality of groups of V-shaped microchannels distributed in an array. Specifically, each microchannel portion in the plurality of microchannel portions 53 can include a plurality of microchannel layers arranged in parallel in the direction perpendicular to the first cavity 52 to the second cavity 54. Each microchannel layer can be composed of a plurality of groups of V-shaped microchannels distributed in an array. Wherein, the top inlet of the V-shaped microchannel is connected to the first cavity 52 or the sub-cavity 56, and the bottom outlet of the V-shaped microchannel is connected to the sub-cavity 56 or the second cavity 54, and the top inlet of the plurality of groups of V-shaped microchannels can be connected to improve the mixing effect. The sub-cavity 56 located between two adjacent microchannel portions can mix the 5-hydroxymethylfurfural, the catalyst and the organic solvent between the different microchannel layers in the microchannel portion to improve the mixing effect.

[0082] According to an embodiment of the present invention, the widths of the microchannels in the plurality of microchannel portions 53 may be equal.

[0083] More preferably, the widths of the microchannels in the plurality of microchannel portions 53 decrease in sequence from the first cavity 52 to the second cavity 54 .

[0084] For example, the microchannel portion 53 includes a first microchannel portion 531 and a second microchannel portion 532, wherein the first microchannel portion 531 is close to the first cavity 52, and the second microchannel portion 532 is close to the second cavity 54. The width of the microchannel in the first microchannel portion 531 can be equal to the width of the microchannel in the second microchannel portion 532. The width of the microchannel in the first microchannel portion 531 can also be greater than the width of the microchannel in the second microchannel portion 532. In this case, the micromixer has a better mixing effect.

[0085] According to an embodiment of the present invention, the width of the microchannels in the plurality of microchannel portions 53 is 0.5 to 0.8 mm. Specifically, the width of the microchannels in the plurality of microchannel portions 53 may be 0.5 mm, 0.6 mm, 0.7 mm or 0.8 mm, preferably 0.6 mm.

[0086] According to an embodiment of the present invention, the height of the microchannels in the plurality of microchannel portions 53 is 0.2-0.4 mm. Specifically, the height of the microchannels in the plurality of microchannel portions 53 may be 0.2 mm, 0.3 mm or 0.4 mm, preferably 0.3 mm.

[0087] According to an embodiment of the present invention, the plurality of microchannel portions 53 may further include other microchannel portions located between the first microchannel portion 531 and the second microchannel portion 532. The width of the microchannel in the other microchannel portion may be 0.5-0.8 mm, and the height may be 0.2-0.4 mm. In the direction from the first cavity 52 to the second cavity 54, the width of each microchannel portion may be designed in order from large to small to obtain a better mixing effect.

[0088] According to an embodiment of the present invention, Figure 3 and Figure 4 As shown, the dynamic tubular reactor may include a reaction cylinder 61 and a rotating shaft 62, and the rotation speed of the rotating shaft 62 is 500-800 r / min. Specifically, the rotation speed of the rotating shaft 62 may be 500 r / min, 600 r / min, 700 r / min or 800 r / min. The capacity of the reaction cylinder 61 is 50-500 mL. Specifically, the capacity of the reaction cylinder 61 may be 50 mL, 100 mL, 150 mL, 200 mL, 300 mL, 400 mL or 500 mL. By rotating the rotating shaft, the material flow presents a plug flow characteristic, effectively reducing back mixing and improving the selectivity and conversion rate of the reaction.

[0089] According to the embodiment of the present invention, fins of different shapes can be distributed on the rotating shaft 62 according to the reaction requirements to enhance the mixing effect. The outer diameter of the dynamic tubular reactor 6 can be provided with a large-area contact circulation heating and insulation system to quickly and accurately adjust the temperature of the reaction system, thereby improving production efficiency and consistency, which is conducive to large-scale industrial promotion.

[0090] Figure 5 The device diagram of 5,5'-oxybismethylene-2-furfural provided in an embodiment of the present invention is schematically shown.

[0091] like Figure 5 As shown, the device for preparing 5,5'-oxybismethylene-2-furfural may include: a first liquid phase channel 1, a second liquid phase channel 2, a first plunger pump 3, a second plunger pump 4, a micro mixer 5, a dynamic tubular reactor 6, a water removal membrane 7, a quenching device 8, a back pressure valve 9 and an analysis device 10.

[0092] According to an embodiment of the present invention, a first plunger pump 3 may be provided on the first liquid phase channel 1, and 5-hydroxymethylfurfural and an organic solvent or 5-hydroxymethylfurfural, a catalyst and an organic solvent may be pumped into the micro-mixer 5 by the first plunger pump 3. A second plunger pump 4 may be provided on the second liquid phase channel 2, and the catalyst and an organic solvent may be pumped into the micro-mixer 5 by the second plunger pump, or may not be transported.

[0093] According to an embodiment of the present invention, 5-hydroxymethylfurfural, catalyst and organic solvent may be transported to the micromixer 5 through the first liquid phase channel 1, and the 5-hydroxymethylfurfural, catalyst and organic solvent may be mixed in the micromixer 5 to obtain a mixture.

[0094] In the process of implementing the present invention, it is found that when 5-hydroxymethylfurfural, a catalyst and an organic solvent are transported through the first liquid phase channel 1, the catalyst (for example, the catalyst is ferric sulfate) may not be completely dissolved, and the catalyst is likely to be deposited in the first liquid phase channel 1, affecting the smooth progress of subsequent mixing and reaction. It can be considered to promote the dissolution of the catalyst by heating, but this may bring new problems: the self-etherification reaction may proceed in advance in the first liquid phase channel 1.

[0095] To solve the above problems, 5-hydroxymethylfurfural and an organic solvent can be transported to the micromixer 5 through the first liquid phase channel 1; the catalyst and the organic solvent can be transported to the micromixer 5 through the second liquid phase channel 2; and then the 5-hydroxymethylfurfural, the catalyst and the organic solvent are mixed in the micromixer 5 to obtain a mixture. By transporting 5-hydroxymethylfurfural and the catalyst separately, the second liquid phase channel 2 can be heated separately to promote the dissolution of the catalyst, so that the catalyst can be smoothly transported to the micromixer 5 for mixing, and the self-etherification reaction can be avoided from proceeding prematurely.

[0096] Therefore, the micro mixer 5 can be a two-way, three-way or four-way mixer, which is arranged downstream of the first liquid phase channel 1 and / or the second liquid phase channel 2 and upstream of the dynamic tubular reactor 6 .

[0097] When the micro mixer 5 is suitable for continuously receiving 5-hydroxymethylfurfural, catalyst and organic solvent from the first liquid phase channel 1 to mix them to obtain a mixed liquid, the micro mixer 5 may be a two-way mixer.

[0098] When it is suitable for continuously receiving 5-hydroxymethylfurfural and organic solvent from the first liquid phase channel 1 and catalyst and organic solvent from the second liquid phase channel 2, the micro mixer 5 can be a three-way mixer. Specifically, the micro mixer 5 can include: two inlet channels: one inlet channel is connected to the first liquid phase channel 1, used to receive 5-hydroxymethylfurfural and organic solvent; one inlet channel is connected to the second liquid phase channel 2, used to receive catalyst and organic solvent; one outlet channel 55 is connected to the dynamic tubular reactor 6, used to output the mixed liquid.

[0099] The present application does not limit the shape and size of the inlet channel 51 and the outlet channel 55. For example, the inlet channel 51 and the outlet channel 55 of the micro mixer 5 can both be circular channels with an outer diameter of 3.0 mm and an inner diameter of 2.0 mm.

[0100] According to an embodiment of the present invention, a water removal membrane 7 , a quenching device 8 , a back pressure valve 9 and an analysis device 10 may be further arranged downstream of the dynamic tubular reactor 6 .

[0101] The dehydration membrane 7 can remove the water generated in the reaction solution, and the reaction solution after dehydration can be recycled to continue the reaction. Specifically, the reaction solution after dehydration can be transported to the micro mixer 5 through the third liquid phase channel, and the micro mixer 5 can be a four-way micro mixer.

[0102] The quenching device 8 is suitable for ensuring that the fluid is cooled quickly and evenly in the system. For example, a coil structure, a plate heat exchanger or other heat exchange structure that can effectively reduce the temperature of the fluid can be adopted.

[0103] The back pressure valve 9 is suitable for adjusting the pressure and flow rate of the fluid to ensure stable flow and reaction of the fluid in the system. For example, a spring-loaded structure, a piston structure or other mechanical structures that can accurately control the pressure and flow rate of the fluid can be adopted.

[0104] The analysis device 10 is suitable for qualitative and / or quantitative analysis of the compound. The analysis device 10 can also be located before the water removal membrane, suitable for analyzing the reaction liquid output from the dynamic tubular reactor 6; it can also be located after the water removal membrane, suitable for analyzing the reaction liquid after water removal.

[0105] The present invention is further described below by way of examples. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive explanation of embodiments of the present invention. However, it is apparent that one or more embodiments may be implemented without these specific details. Moreover, in the absence of conflict, the details in the following embodiments may be combined arbitrarily into other feasible embodiments.

[0106] Example 1

[0107] This embodiment provides a method for preparing 5,5'-oxybismethylene-2-furfural, comprising the following steps:

[0108] After the reaction device is connected and cleaned, the back pressure valve is fixed to 2 MPa pressure. An acetonitrile solution of 5-hydroxymethylfurfural (HMF) with a concentration of 8wt% is pumped in at a flow rate of 24.25 mL / min, and an acetonitrile solution of p-toluenesulfonic acid catalyst with a concentration of 0.96wt% is pumped in at a flow rate of 72.75 mL / min. After mixing in a micro mixer, a mixture of 6wt% 5-hydroxymethylfurfural and 0.24wt% p-toluenesulfonic acid catalyst is obtained. The reaction mixture is passed into a dynamic tubular reactor with a capacity of 97 mL at 80°C for 2 minutes to obtain a reaction solution, which is then qualitatively and quantitatively detected. The reaction mixture is then purified. The purification steps are as follows: the hot reactant is filtered while hot, and the filtrate is rotary evaporated to obtain a crude 5,5'-oxybis(methylene)-2-furfural product. The crude product of 5,5'-oxybis(methylene)-2-furfural was recrystallized from methanol: water = 1:1 (volume ratio) to obtain pure 5,5'-oxybis(methylene)-2-furfural, with a reaction molar yield of 95.63%. Gas chromatography was used for qualitative and quantitative detection. Finally, the crude product of 5,5'-oxybis(methylene)-2-furfural and the purified crude product and pure product were detected by nuclear magnetic resonance hydrogen spectrum, such as Figure 6 , Figure 7 shown.

[0109] The device for preparing 5,5'-oxybis(methylene)-2-furfural is as follows Figures 2~5 As shown, it includes: a first liquid phase channel 1, a second liquid phase channel 2, a first plunger pump 3, a second plunger pump 4, a micro mixer 5, a dynamic tubular reactor 6, a water removal membrane 7, a quenching device 8, a back pressure valve 9 and an analysis device 10. 5-Hydroxymethylfurfural, a catalyst and an organic solvent are transported to the micro mixer 5 through the first liquid phase channel 1.

[0110] The width of the microchannel in the micromixer 5 is 0.6 mm and the height is 0.3 mm. The rotation speed of the rotating shaft in the dynamic tubular reactor 6 is 700 r / min; the width of the reaction cylinder is 600 mm, the outer diameter is 160 mm, and the inner diameter is 70 mm.

[0111] Embodiment 2~embodiment 22:

[0112] The preparation process of Example 2 to Example 22 refers to Example 1, except that the reaction parameters are changed as shown in Table 1 below, including: in Example 2 to Example 5, the concentration of the reaction substrate 5-hydroxymethylfurfural (HMF) is adjusted to 0.5wt%, 2wt%, 7.5wt%, and 9wt%, respectively; in Example 6, p-toluenesulfonic acid is adjusted to sulfuric acid; in Example 7 to Example 9, the concentration of p-toluenesulfonic acid is adjusted to 0.05wt%, 0.12wt%, and 0.16wt%; in Example 10 to Example 13, the temperature is adjusted to 60°C, 70°C, 90°C, and 100°C, respectively; in Example 14 to Example 18, the residence time is adjusted to 1 min, 5 min, 8 min, and 10 min, respectively. min, 15min; in Example 19, the organic solvent is adjusted to acetone; in Example 20 to Example 22, the catalysts are adjusted to phosphomolybdic acid, ferric chloride and ferric sulfate, respectively, 5-hydroxymethylfurfural and the organic solvent are transported to the micromixer 5 through the first liquid phase channel 1, and the catalyst and the organic solvent are transported to the micromixer 5 through the second liquid phase channel 2; the reaction parameters and product yields are shown in Table 1 below.

[0113] Table 1

[0114]

[0115] By comparing Examples 1 to 22, it can be seen that the yield of 5,5'-oxybis(methylene)-2-furfural prepared in Example 10 is 99.9%, which is the highest yield. That is, when the concentration of the substrate 5-hydroxymethylfurfural is 6wt%, the organic acid is p-toluenesulfonic acid, the concentration of the organic acid is 0.24wt%, the solvent is acetonitrile, the temperature of the self-etherification reaction is 60°C, and the reaction time is 2 min, the yield of the prepared 5,5'-oxybis(methylene)-2-furfural is the best.

[0116] Comparative Example 1

[0117] The preparation method of synthesizing 5,5'-oxybismethylene-2-furfural by dehydrating 5-hydroxymethylfurfural in a reaction bottle comprises the following steps:

[0118] Into a 250 mL three-necked flask equipped with a Dean-Stark apparatus were added 3.0030 g of 5-hydroxymethylfurfural, 50.16 g of acetone and 0.1332 g of p-toluenesulfonic acid catalyst, and the mixture was reacted at 60°C for 1 h, 2 h, 3 h, 4 h, 5 h and 6 h. Samples were taken and determined by gas chromatography. The molar yields of 5,5'-oxybismethylene-2-furfural were 67.34%, 68.27%, 70.49%, 72.31%, 71.23% and 73.26%, respectively.

[0119] Comparative Example 2

[0120] The preparation process of Comparative Example 2 refers to that of Example 1, except that the micro-mixer 5 is adjusted to a three-way pipe, and the molar yield of 5,5'-oxybismethylene-2-furfural is 87.53%.

[0121] By comparing Example 1 of the present invention with Comparative Example 1, it can be seen that the present invention uses a micro-mixer and a dynamic tubular reactor to prepare a method for 5,5'-oxybismethylene-2-furfural, which shortens the reaction time compared with a kettle reactor, has a higher product yield, and avoids the safety problems caused by the reactor. By comparing Example 1 of the present invention with Comparative Example 2, it can be seen that the use of a micro-mixer and a dynamic tubular reactor can increase the yield of 5,5'-oxybismethylene-2-furfural.

[0122] The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made to the technical method by any technician familiar with the art within the spirit and principle of the present invention is still included in the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing 5,5'-oxybismethylene-2-furfural, comprising: Mixing 5-hydroxymethylfurfural, a catalyst and an organic solvent in a micromixer to obtain a mixture; The mixture is continuously transported to a dynamic tubular reactor for self-etherification reaction to obtain a reaction solution containing 5,5'-oxybismethylene-2-furfural, wherein the inner diameter of the dynamic tubular reactor is 60-80 mm.

2. The method according to claim 1, wherein: The micromixer comprises an inlet channel, a first cavity, a plurality of microchannel portions, a second cavity and an outlet channel connected in sequence, wherein the plurality of microchannel portions are arranged in an array in a direction from the first cavity to the second cavity, and a sub-cavity is provided between two adjacent microchannel portions, and the plurality of microchannel portions are used to mix the 5-hydroxymethylfurfural, the catalyst and the organic solvent under microscale conditions.

3. The method according to claim 2, wherein: The microchannel portion includes a plurality of microchannel layers distributed in an array, and the microchannel layer is composed of a plurality of groups of V-shaped microchannels distributed in an array.

4. The method according to claim 2, wherein: The widths of the microchannels in the plurality of microchannel portions decrease in sequence in a direction from the first cavity to the second cavity; The width of the microchannels in the plurality of microchannel portions is 0.5 to 0.8 mm; The height of the microchannels in the multiple microchannel parts is 0.2-0.4 mm.

5. The method according to any one of claims 1 to 4, wherein The dynamic tubular reactor comprises a reaction cylinder and a rotating shaft, and the rotating speed of the rotating shaft is 500-800 r / min; The capacity of the reaction cylinder is 50-500 mL.

6. The method according to any one of claims 1 to 4, wherein The self-etherification reaction is carried out at 25-165° C., and the dwell time in the dynamic tubular reactor is 1-15 min.

7. The method according to any one of claims 1 to 4, further comprising: Dehydrating the reaction solution containing 5,5'-oxybismethylene-2-furfural through a dehydrating membrane to obtain a dehydrated reaction solution; The reaction liquid after dehydration is transported to the micro mixer through the third liquid phase channel.

8. The method according to any one of claims 1 to 4, wherein The step of mixing 5-hydroxymethylfurfural, a catalyst and an organic solvent in a micromixer comprises: The 5-hydroxymethylfurfural and the organic solvent are transported to the micromixer through the first liquid phase channel, or the 5-hydroxymethylfurfural, the catalyst and the organic solvent are transported to the micromixer through the first liquid phase channel; The catalyst and the organic solvent are transported into the micromixer through the second liquid phase channel, or are not transported.

9. The method according to any one of claims 1 to 4, wherein The concentration of the 5-hydroxymethylfurfural is 0.5wt%~15wt%; The catalyst is one or more of p-toluenesulfonic acid, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, phosphomolybdic acid, ferric chloride and ferric sulfate; The concentration of the catalyst is 0.05wt%~1wt%; The organic solvent is one or more of dimethyl carbonate, toluene, acetone, acetonitrile and dichloromethane.

10. A device for preparing 5,5'-oxybismethylene-2-furfural, comprising: A micro mixer, adapted to continuously receive 5-hydroxymethylfurfural, a catalyst and an organic solvent, and mix them to obtain a mixture; The dynamic tubular reactor is located downstream of the micromixer and is suitable for continuously receiving the mixture from the micromixer and subjecting the mixture to a self-etherification reaction to obtain a reaction solution containing 5,5'-oxybismethylene-2-furfural, wherein the inner diameter of the dynamic tubular reactor is 60-80 mm.

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