Method for preparing polytetrahydrofuran

Abstract

The invention belongs to the technical field of polymer preparation, and relates to a method for preparing polytetrahydrofuran. The invention relates to a method for preparing polytetrahydrofuran, which is characterized by comprising the following steps: pumping tetrahydrofuran into a micro-flow field reactor of a micro-flow field reaction device, and carrying out polymerization reaction under the action of a catalyst to obtain the polytetrahydrofuran, wherein no extra solvent is added in the polymerization reaction; the catalyst is loaded in the micro-flow field reactor. By optimizing the working conditions of the micro-flow field reactor, the production efficiency of the polytetrahydrofuran is improved, the conversion rate of the tetrahydrofuran is high and can reach 89%, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer preparation and relates to a method for preparing polytetrahydrofuran. Background Art

[0002] Microfluidic reaction technology is a technology that controls chemical reactions at the micrometer scale, and has the advantages of high efficiency, high selectivity, and low energy consumption. Polytetramethylene ether glycol (PTMEG), also known as polytetramethylene ether glycol, is an important polymer material with excellent performance and broad application prospects.

[0003] In the process of manufacturing polytetrahydrofuran, traditional synthesis methods usually use high pressure, high temperature, high energy consumption conditions, and the reaction process is difficult to control, and the product quality is unstable. The introduction of microfluidic reaction technology can effectively solve these problems.

[0004] The reaction in the microfluidic reactor is carried out in a micron-sized channel, and the mixing and transfer process of the reactants in the channel can be precisely controlled. By optimizing the structure and working conditions of the microfluidic reactor, the synthesis process of polytetrahydrofuran can be precisely controlled to improve the quality and stability of the product. In addition, microfluidic reaction technology can also achieve continuous production, improve production efficiency, and reduce production costs. Therefore, the use of microfluidic reaction technology to manufacture polytetrahydrofuran has high technical feasibility and economy. In general, microfluidic reaction technology has broad application prospects in the field of manufacturing polytetrahydrofuran, and can bring important technological progress and economic benefits to the polymer materials industry.

[0005] Traditional synthesis methods include an acid catalyst fixed bed method, a bio-based polytetrahydrofuran preparation method, and a solid acid catalyst conventional reactor method; among them, the temperature gradient control of the acid catalyst fixed bed method used in Chinese patent CN 101466768B is relatively difficult, and may cause catalyst blockage and uneven reaction, limiting the reaction rate and efficiency, and the evaporation residue (i.e., the yield of the product) is only 60.1% at most; the bio-based polytetrahydrofuran preparation method used in Chinese patent CN 115725066A can improve the catalytic efficiency, but it needs to be reacted in a 7.0-8.5MPa high-pressure CO2 environment, the reaction conditions are harsh, and the catalytic efficiency of the catalyst is low, which is not suitable for subsequent use; when polytetrahydrofuran is prepared by a solid acid catalyst conventional reactor method in Chinese patent CN 1796436A, although high pressure is not required, promoters such as ethylene oxide and propylene oxide need to be added to promote the reaction, and the yield of the product polytetrahydrofuran is only 60.1% at most, the operation process is complicated, and the subsequent removal of the solvent will cause environmental pollution and recycling difficulties. Chinese patent CN 115124708A discloses a method for synthesizing polytetrahydrofuran using a microchannel reactor, wherein tetrahydrofuran and a heteropoly acid are mixed to obtain a heteropoly acid catalyst phase; tetrahydrofuran is mixed with water to obtain an organic phase; the heteropoly acid catalyst phase and the organic phase are simultaneously pumped into a microchannel reactor for polymerization to obtain polytetrahydrofuran. Although the method uses microchannel reaction technology to shorten the reaction time and has mild reaction conditions, the monomer conversion rate of the product polytetrahydrofuran is low, with a maximum of only 32.6%. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a new preparation method of polytetrahydrofuran in view of the deficiencies of the prior art. The present invention adopts a solid acid as a catalyst, the reaction is carried out under the protection of an inert gas, and no additional solvent or reaction accelerator is required. The reaction greatly increases the reaction rate when using microflow field technology, avoids the disadvantages of experimental waste, separation difficulty, etc. The present invention realizes the preparation of polytetrahydrofuran under relatively mild reaction conditions, and the conversion rate can be controlled by flow rate and temperature, and can reach up to 89%.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] The invention discloses a method for preparing polytetrahydrofuran, wherein tetrahydrofuran is pumped into a microfluidic reactor of a microfluidic reactor device, and a polymerization reaction is carried out under the action of a catalyst to obtain polytetrahydrofuran;

[0009] Wherein, no additional solvent is added in the polymerization reaction; and the catalyst is loaded in a microfluidic field reactor.

[0010] Wherein, no additional regulator or promoter is required to be added in the polymerization reaction.

[0011] Wherein, no additional solvent, such as water, is added during the polymerization reaction.

[0012] In some embodiments, the catalyst is any one or a combination of oxide catalysts, sulfide catalysts, metal salt catalysts and solid acid catalysts.

[0013] In some embodiments, the oxide catalyst is CuO; the sulfide catalyst is CuS; the metal salt catalyst is any one or a combination of [Cu(CH3CN)4][PF6] and [Cu(CH3CN)4][BF4]; and the solid acid catalyst is phosphotungstic acid.

[0014] In some embodiments, preferably, the catalyst is a solid acid catalyst; the solid acid catalyst is phosphotungstic acid.

[0015] In some embodiments, the mass of the catalyst accounts for 0.5% to 5.0% of the mass of the tetrahydrofuran.

[0016] In some embodiments, preferably, the mass of the catalyst accounts for 1.0% to 5.0% of the mass of the tetrahydrofuran, and more preferably 1.0% to 2.5%.

[0017] Wherein, the amount of the catalyst loaded in the microfluidic field reactor is calculated according to the amount of the raw material of tetrahydrofuran.

[0018] In some embodiments, the flow rate of the tetrahydrofuran pumped into the microfluidic reactor of the microfluidic reaction device is 0.1 mL / min to 2.0 mL / min.

[0019] In some embodiments, preferably, the flow rate of the tetrahydrofuran pumped into the microfluidic reactor of the microfluidic reaction device is 0.1 mL / min to 1.0 mL / min, more preferably 0.1 mL / min to 0.5 mL / min, and even more preferably 0.1 mL / min to 0.15 mL / min.

[0020] In some embodiments, the polymerization reaction has a reaction temperature of 20°C to 60°C.

[0021] In some embodiments, preferably, the polymerization reaction has a reaction temperature of 30°C to 60°C, and more preferably 45°C to 60°C.

[0022] In some embodiments, the polymerization reaction has a reaction residence time of 10 to 200 minutes.

[0023] In some embodiments, preferably, the polymerization reaction has a reaction residence time of 40 to 200 minutes.

[0024] In some embodiments, the polymerization reaction is carried out at normal pressure; the polymerization reaction is carried out under the protection of an inert gas.

[0025] Among them, preferably, the inert gas is nitrogen.

[0026] Wherein, air cannot enter during the polymerization reaction.

[0027] In some embodiments, the microfluidic field reaction device includes a connecting pipe, a syringe pump, a microfluidic field reactor and a receiver; the syringe pump, the microfluidic field reactor and the receiver are connected in series in sequence through the connecting pipe.

[0028] In some embodiments, the catalyst is loaded in a microfluidic reactor, and tetrahydrofuran is pumped into the microfluidic reactor of the microfluidic reaction device under inert gas protection to carry out polymerization reaction at normal pressure to obtain polytetrahydrofuran.

[0029] Wherein, the diameter of the connecting pipe is 1mm to 2mm.

[0030] Wherein, the volume of the microfluidic field reactor is 10 to 20 mL.

[0031] Wherein, the microfluidic field reactor is a tubular microfluidic field reactor with an inner diameter of 1 mm.

[0032] Wherein, the reaction temperature of the microfluidic field reactor is controlled by an oil bath.

[0033] After the polymerization reaction is completed, water is added to the microfluidic reactor to terminate the reaction, and the liquid flowing out of the microfluidic reactor is collected, and toluene is added for azeotropic rotary evaporation to obtain an oily liquid, namely polytetrahydrofuran.

[0034] Beneficial effects:

[0035] (1) The method for preparing polytetrahydrofuran provided by the present invention uses microfluidic field reaction technology to accurately control the mixing and transfer process of reactants in the microchannel, and the reaction is more efficient and comprehensive; by optimizing the working conditions of the microfluidic field reactor, the production efficiency of polytetrahydrofuran is improved, the conversion rate of tetrahydrofuran is high, up to 89%, and the production cost is reduced. The method for preparing polytetrahydrofuran provided by the present invention has a wide range of application prospects in the field of synthesizing polytetrahydrofuran, and can bring important technological progress and economic benefits to the polymer material industry.

[0036] (2) The method for preparing polytetrahydrofuran provided by the present invention improves the safety of the reaction process and reduces pollution emissions.

[0037] (3) The method for preparing polytetrahydrofuran provided by the present invention improves product quality.

[0038] (4) The method for preparing polytetrahydrofuran provided by the present invention reduces waste and the solid acid can be reused.

[0039] (5) The method for preparing polytetrahydrofuran provided by the present invention has simple temperature control and simple operation, does not need to be carried out under high pressure, and does not need to add additional promoters or solvents and other reagents, and the reaction is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0041] Figure 1 This is the H NMR spectrum of the polytetrahydrofuran prepared in Example 1.

[0042] Figure 2 Schematic diagram of the process of the microfluidic reaction device used in the embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the contents described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0044] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0045] The calculation formula of the monomer conversion rate of tetrahydrofuran in the embodiment of the present invention is: conversion rate (%) = (m / M) / n*100%; wherein, m: the mass of the obtained polytetrahydrofuran, M: the molecular weight of a single repeating unit of polytetrahydrofuran, and n: the molar number of tetrahydrofuran used.

[0046] The mass content of the catalyst in the embodiments of the present invention is expressed as the percentage of the mass of the catalyst to the mass of tetrahydrofuran.

[0047] The schematic diagram of the process of the microfluidic reaction device used in the embodiment of the present invention is as follows Figure 2As shown, the microfluidic field reaction device includes a connecting pipe, a syringe pump, a microfluidic field reactor and a receiver (receiving polytetrahydrofuran); the syringe pump, the microfluidic field reactor and the receiver are sequentially connected in series through the connecting pipe. Specifically, the catalyst is loaded in the microfluidic field reactor, and tetrahydrofuran is pumped into the microfluidic field reactor of the microfluidic field reaction device to perform a polymerization reaction at normal pressure to obtain polytetrahydrofuran.

[0048] Wherein, the diameter of the connecting pipe is 1mm.

[0049] Wherein, the volume of the microfluidic field reactor is 20 mL.

[0050] Wherein, the microfluidic field reactor is a tubular microfluidic field reactor with an inner diameter of 1 mm.

[0051] Embodiment 1:

[0052] First, phosphotungstic acid (0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is airtight and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen for three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 45° C.; tetrahydrofuran (20 g, 0.28 mol) is introduced to carry out a polymerization reaction under normal pressure, with the flow rate controlled at 0.10 mL / min and the reaction residence time being 200 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the obtained oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 78%.

[0053] The product polytetrahydrofuran 1 H NMR spectrum is shown in Figure 1 , the same below.

[0054] The specific NMR data are: 1 H NMR (400MHz, Chloroform-d) δ3.33 (t, J = 5.7Hz, 60H), 1.54 (d, J = 5.7Hz, 60H), 1.17 (s, 2H).

[0055] Embodiment 2:

[0056] First, phosphotungstic acid (0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is airtight and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen for three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 50° C.; tetrahydrofuran (20 g, 0.28 mol) is introduced to carry out a polymerization reaction under normal pressure, with the flow rate controlled at 0.10 mL / min and the reaction residence time being 200 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the obtained oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 88%.

[0057] Embodiment 3:

[0058] First, phosphotungstic acid (0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is leak-proof and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen for three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 60° C.; tetrahydrofuran (20 g, 0.28 mol) is introduced to carry out a polymerization reaction under normal pressure, with the flow rate controlled at 0.10 mL / min and the reaction residence time being 200 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the obtained oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 89%.

[0059] Embodiment 4:

[0060] First, phosphotungstic acid (0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is leak-proof and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen for three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 45° C.; tetrahydrofuran (20 g, 0.28 mol) is introduced to carry out a polymerization reaction under normal pressure, with the flow rate controlled at 0.15 mL / min and the reaction residence time being 133 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the obtained oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 83%.

[0061] Embodiment 5:

[0062] First, phosphotungstic acid (0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is leak-proof and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen for three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 45° C.; tetrahydrofuran (20 g, 0.28 mol) is introduced to carry out a polymerization reaction under normal pressure, with the flow rate controlled at 0.20 mL / min and the reaction residence time being 100 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the obtained oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 61%.

[0063] Embodiment 6:

[0064] First, [Cu(CH3CN)4][PF6] (tetraacetonitrile copper (I) hexafluorophosphate, 0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is airtight and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 50°C; tetrahydrofuran (20 g, 0.28 mol) is introduced, and a polymerization reaction is carried out under normal pressure, with the flow rate controlled at 0.10 mL / min and the reaction residence time being 200 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the resulting oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 69%.

[0065] Embodiment 7:

[0066] First, [Cu(CH3CN)4][BF4] (tetrafluoroborate tetraacetonitrile copper (I), 0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is airtight and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 50°C; tetrahydrofuran (20 g, 0.28 mol) is introduced, and a polymerization reaction is carried out under normal pressure, with the flow rate controlled at 0.10 mL / min and the reaction residence time being 200 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the resulting oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 63%.

[0067] Embodiment 8:

[0068] First, CuO (0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is leak-proof and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen for three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 40° C.; tetrahydrofuran (20 g, 0.28 mol) is introduced to carry out a polymerization reaction under normal pressure, with the flow rate controlled at 0.5 mL / min and the reaction residence time being 40 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the obtained oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 67%.

[0069] Embodiment 9:

[0070] First, CuS (0.2 g, 1 wt%) is placed in a microfluidic reactor to ensure that the microfluidic reactor is leak-proof and that no air can enter during the reaction; the air in the microfluidic reactor is replaced with nitrogen three to five times to ensure that all the air in the microfluidic reactor is replaced; the temperature in the microfluidic reactor (20 mL) is raised to 50° C.; tetrahydrofuran (20 g, 0.28 mol) is introduced to carry out a polymerization reaction under normal pressure, with the flow rate controlled at 0.15 mL / min and the reaction residence time being 133 min; after the reaction is completed, water is added to the microfluidic reactor to terminate the reaction, the liquid flowing out of the microfluidic reactor is collected, toluene is added for azeotropic rotary evaporation, and the obtained oily liquid is polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran is 70%.

[0071] Comparative Example 1:

[0072] First, phosphotungstic acid (0.02 g, 1 wt%) was placed in a conventional reactor, and tetrahydrofuran (2 g, 28 mmol) was added, and the air in the reaction device was replaced with nitrogen for three to five times to ensure that the reaction device was leak-proof; after ensuring that all the air in the reaction device was replaced, the temperature was raised to 45° C., and a polymerization reaction was carried out under normal pressure for 12 h; after the reaction was completed, water was added to terminate the reaction, the reaction liquid was collected, and toluene was added for azeotropic rotary evaporation, and the obtained oily liquid was polytetrahydrofuran, and the monomer conversion rate of tetrahydrofuran was 53%.

[0073] The detection results of the polytetrahydrofuran products prepared under different reaction conditions in Examples 1 to 9 and Comparative Example 1 are as follows:

[0074] Table 1 Test results of polytetrahydrofuran products under different reaction conditions

[0075]

[0076] in conclusion:

[0077] (1) From the comparison of the results of Example 1, Example 2 and Example 3, it can be seen that the molecular weight and conversion rate of the polymer can be increased by appropriately increasing the reaction temperature. Although the conversion rate of tetrahydrofuran can be increased when the temperature is too high, the molecular weight of the product decreases instead; (2) From the comparison of the results of Example 1, Example 4 and Example 5, it can be seen that the molecular weight of the polymer product increases when the flow rate of tetrahydrofuran is increased, but the conversion rate gradually decreases. From the above results, it can be seen that increasing the flow rate of tetrahydrofuran can increase the molecular weight of the polymer product, and appropriately increasing the reaction temperature can increase the molecular weight and conversion rate of the polymer.

[0078] (3) By comparing Examples 6 to 9 with Examples 1 to 5, it can be seen that the catalytic efficiency of solid acid phosphotungstic acid is better than that of oxide acid catalysts (CuO), sulfide acid catalysts (CuS), and metal salt acid catalysts ([Cu(CH3CN)4][PF6] or [Cu(CH3CN)4][BF4]).

[0079] (4) By comparing Examples 1 to 5 with Comparative Example 1, it can be seen that the polymerization time required for polymerization using a microchannel reactor is significantly less than that using a kettle reactor, and the tetrahydrofuran conversion rate is also significantly higher than that using a kettle reactor. Therefore, the present invention uses microchannel reaction technology to synthesize polytetrahydrofuran, which can not only shorten the polymerization reaction time, but also effectively improve the tetrahydrofuran conversion rate, while continuous production, greatly improving production efficiency.

[0080] Embodiment 10:

[0081] The experimental method of this embodiment is the same as that of embodiment 2, except that the amount of phosphotungstic acid is adjusted. The mass of phosphotungstic acid accounts for 0.5%, 2.5% and 5.0% of the mass of tetrahydrofuran, respectively. The specific results are shown in Table 2 below.

[0082] Table 2

[0083]

[0084] By comparing Example 2 with the above table data, it can be seen that adjusting the amount of phosphotungstic acid can improve the conversion rate of tetrahydrofuran monomer to a certain extent, but the number average molecular weight of polytetrahydrofuran shows a decreasing trend.

[0085] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0086] The present invention provides a method and idea for preparing polytetrahydrofuran. There are many methods and approaches to realize the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be realized by existing technologies.

Claims

1. A method for preparing polytetrahydrofuran, characterized in that: The tetrahydrofuran is pumped into a microfluidic reactor of a microfluidic reactor device, and a polymerization reaction is carried out under the action of a catalyst to obtain polytetrahydrofuran; Wherein, no additional solvent is added in the polymerization reaction; and the catalyst is loaded in a microfluidic field reactor.

2. The method according to claim 1, characterized in that: The catalyst is any one or a combination of oxide catalysts, sulfide catalysts, metal salt catalysts and solid acid catalysts.

3. The method according to claim 2, characterized in that The oxide catalyst is CuO; the sulfide catalyst is CuS; the metal salt catalyst is any one of [Cu(CH3CN)4][PF6] and [Cu(CH3CN)4][BF4] or a combination of two thereof; and the solid acid catalyst is phosphotungstic acid.

4. The method according to claim 1, characterized in that The mass of the catalyst accounts for 0.5% to 5.0% of the mass of the tetrahydrofuran.

5. The method according to claim 1, characterized in that The flow rate of the tetrahydrofuran pumped into the microfluidic reactor of the microfluidic reaction device is 0.1 mL / min to 2.0 mL / min.

6. The method according to claim 1, characterized in that The polymerization reaction has a reaction temperature of 20°C to 60°C.

7. The method according to claim 1, characterized in that The polymerization reaction has a reaction residence time of 10 to 200 minutes.

8. The method according to claim 1, characterized in that The polymerization reaction is carried out under the protection of an inert gas.

9. The method according to claim 1, characterized in that: The microfluidic field reaction device comprises a connecting pipe, an injection pump, a microfluidic field reactor and a receiver; the injection pump, the microfluidic field reactor and the receiver are sequentially connected in series through the connecting pipe.

10. The method according to any one of claims 1 to 9, characterized in that: The catalyst is loaded in a microfluidic reactor and protected by inert gas. Tetrahydrofuran is pumped into the microfluidic reactor of the microfluidic reaction device to carry out polymerization reaction at normal pressure to obtain polytetrahydrofuran.

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