Preparation method and application of low-cost 1, 4-naphthalene diphenol and polyaryletherketone homopolymer thereof

Abstract

The invention provides a preparation method and application of low-cost 1, 4-naphthalene diphenol and a polyaryletherketone homopolymer of the low-cost 1, 4-naphthalene diphenol. The method comprises the following steps: mixing 1, 4-naphthoquinone, a polar solvent and a catalyst to form a mixture; feeding the mixture into a micro-channel tubular reactor, and introducing hydrogen to carry out continuous catalytic hydrogenation reduction reaction; separating the catalyst to obtain a reaction solution containing 1, 4-naphthalene diphenol; adding a non-polar solvent into the reaction liquid for crystallization; and separating to obtain a 1, 4-naphthalene diphenol product. The product obtained by adopting the preparation method and the preparation system provided by the invention is high in purity, good in color, strong in stability and suitable for industrial production, a high-quality raw material is provided for subsequent synthesis of the 1, 4-naphthalene structure polyaryletherketone homopolymer, and smooth proceeding of a polymerization reaction and stability of product quality are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and particularly to a preparation method and application of low-cost 1,4-naphthalenediol and its polyaryletherketone homopolymer. Background Art

[0002] 1,4-Naphthalenediol is an important fine chemical raw material, which is widely used in fields such as pharmaceutical intermediates, rubber additives, resin materials, and thermal recording materials. At present, the industrial preparation of 1,4-naphthalenediol mainly adopts the reduction method of 1,4-naphthoquinone. Common reduction methods include reduction with zinc powder, tin and its salts in hydrochloric acid, electrolytic reduction, reduction with hydrazine hydrate and hydroiodic acid and red phosphorus, and reduction with bisulfite in the presence of organic solvents and water. These methods can be used in the laboratory, but are not suitable for large-scale industrial production.

[0003] When preparing 1,4-naphthalenediol by the hydrogenation reduction process in a polar solvent, due to the use of a large amount of organic solvents, the obtained crystal particles are very fine, which brings difficulties to filtration and separation. In addition, it is difficult to remove the mixed inorganic salts in the product, and the surface of the product is easily oxidized to form a black-purple substance of quinone-hydroquinone, seriously affecting the product quality and stability.

[0004] In the prior art, industrial 1,4-naphthoquinone obtained by gas-phase oxidation of naphthalene is also used for the hydrogenation reduction reaction in a polar solvent by a batch process in a kettle. Although this method can obtain high-purity 1,4-naphthalenediol, the batch process in a kettle has problems such as high safety risks and low production efficiency, which is not conducive to large-scale industrial production. At the same time, the product obtained by this process has fine crystal particles, difficult filtration and separation, and poor product stability, and is prone to oxidation and discoloration during storage. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method and application of low-cost 1,4-naphthalenediol and its polyaryletherketone homopolymer to solve the technical problems such as high safety risks and unstable product quality existing in the prior art.

[0006] To achieve the above purpose, the present invention provides a preparation method of 1,4-naphthalenediol, including the following steps:

[0007] Mix 1,4-naphthoquinone, a polar solvent and a catalyst to form a mixture;

[0008] Feed the mixture into a microchannel tubular reactor;

[0009] In the microchannel tubular reactor, control the reaction temperature and reaction pressure, and introduce hydrogen for continuous catalytic hydrogenation reduction reaction;

[0010] Separate the catalyst to obtain a reaction solution containing 1,4-naphthalenediol.

[0011] Optionally, the polar solvent is selected from one or more of alcohol solvents, diol solvents, ethylene glycol ether solvents, organic acids, organic acid esters, ether solvents, ketone solvents, and organic base solvents, and the amount of the polar solvent is 1 to 30 times the weight of 1,4-naphthalenediol.

[0012] Optionally, the catalyst is selected from one or more of palladium catalyst supported on activated carbon, platinum oxide, platinum colloid, copper chromite, ruthenium catalyst supported on activated carbon, and Raney nickel; preferably, the amount of the catalyst is 0.1 to 5 times the weight of 1,4-naphthoquinone.

[0013] Optionally, the reaction residence time of the continuous catalytic hydrogenation reduction reaction is 3.6 to 3600 seconds, the reaction temperature is from room temperature to 100 °C, and the reaction pressure is 1 to 15 atmospheres.

[0014] Optionally, it further includes a post-treatment step:

[0015] Adding a non-polar solvent to the reaction solution containing 1,4-naphthalenediol for crystallization;

[0016] Separating to obtain 1,4-naphthalenediol product;

[0017] Preferably, before adding the non-polar solvent, it further includes a step of concentrating the reaction solution containing 1,4-naphthalenediol;

[0018] More preferably, the non-polar solvent is selected from one or more of aliphatic hydrocarbons, alicyclic hydrocarbons, or halogenated hydrocarbons, and the amount of the non-polar solvent is 0.5 to 30 times the weight of 1,4-naphthalenediol.

[0019] The present invention also provides a preparation system for preparing 1,4-naphthalenediol, including:

[0020] A metering tank for mixing 1,4-naphthoquinone, polar solvent, and catalyst;

[0021] A diaphragm metering pump connected to the metering tank;

[0022] A microchannel tubular reactor having a mixer inlet, and the mixer inlet is connected to the diaphragm metering pump;

[0023] A liquid hydrogen storage tank, and the liquid hydrogen storage tank is connected to the mixer inlet;

[0024] A control system for controlling the reaction temperature and reaction pressure.

[0025] The present invention also provides a 1,4-naphthalenediol prepared by the above method.

[0026] The present invention also provides the use of the above-mentioned 1,4-naphthalenediol in the preparation of pharmaceutical intermediates, rubber additives, resin materials, dyes or thermal recording materials.

[0027] The present invention also provides a method for preparing a 1,4-naphthalene-structured polyaryletherketone homopolymer using the above-mentioned 1,4-naphthalenediol, comprising the following steps:

[0028] Adding 1,4-naphthalenediol, 4,4'-difluorobenzophenone and potassium carbonate into an organic solvent;

[0029] Adding an azeotropic agent;

[0030] Heating with gradient water removal under nitrogen protection, raising the temperature to 180 - 220 °C and reacting for 8 - 24 hours;

[0031] After cooling, crushing the obtained product and washing it;

[0032] Obtaining a 1,4-naphthalene-structured polyaryletherketone homopolymer after drying;

[0033] Wherein the molar ratio of the 1,4-naphthalenediol to the 4,4'-difluorobenzophenone is 0.8 - 1.2:1;

[0034] Preferably, the organic solvent is selected from one or more of sulfolane, N-methylpyrrolidone or dimethylacetamide;

[0035] Preferably, the azeotropic agent includes toluene or xylene.

[0036] The present invention also provides a 1,4-naphthalene-structured polyaryletherketone homopolymer prepared by the above method.

[0037] Compared with the prior art, the present invention uses a microchannel tube reactor for continuous catalytic hydrogenation reduction reaction, realizing the continuity and automatic control of the reaction, significantly reducing the safety risk and improving the production efficiency; at the same time, by precisely controlling the reaction temperature and pressure, the stability of the product quality is ensured, the product purity is improved, and high-quality raw materials are provided for subsequent polymer synthesis, ensuring the smooth progress of the polymerization reaction and the stability of the product quality.

[0038] Furthermore, the present invention adopts a combined treatment method of polar solvents and non-polar solvents, which not only makes the product crystallization easy to filter, but also improves the storage stability of the product; through the control of the preferred catalyst system and reaction conditions, a high reaction conversion rate and selectivity are achieved, significantly improving the product yield; the microchannel tube reactor system adopted has a simple structure, convenient operation, is easy for industrial production and has low cost.

[0039] Furthermore, the present invention also provides a method for preparing 1,4-naphthalene-structured polyaryletherketone homopolymer using the said 1,4-naphthalenediol, as well as the 1,4-naphthalene-structured polyaryletherketone homopolymer prepared by this method. This method uses the high-purity 1,4-naphthalenediol of the present invention as raw material, and through polycondensation with 4,4'-difluorobenzophenone under specific conditions, a polyaryletherketone homopolymer with a unique structure is obtained. Using 1,4-naphthalenediol to replace the traditional 1,5-naphthalenediol to synthesize polyaryletherketone, the resulting polymer has a more regular molecular structure, exhibits higher crystallinity and mechanical strength, while maintaining good heat resistance, with a glass transition temperature of about 195°C; the 5% thermal weight loss temperature exceeds 500°C.

[0040] Again, the introduction of the 1,4-naphthalene structure enables the naphthalene ring groups on the polymer molecular chain to form stronger π-π interactions with the surface of carbon nanotubes, becoming a surface modifier for carbon nanotubes, which can significantly improve the dispersion of carbon nanotubes in the polymer matrix and enhance the mechanical properties and thermal stability of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic flow chart of the preparation method of 1,4-naphthalenediol in the embodiment of the present invention;

[0042] Figure 2 Schematic module diagram of the preparation system of 1,4-naphthalenediol in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] The present invention will be described in more detail below, in which the preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as a broad guidance for those skilled in the art and not as a limitation to the present invention.

[0044] In the following paragraphs, the present invention will be described more specifically by way of example. According to the following description and claims, the advantages and features of the present invention will be clearer.

[0045] Example 1

[0046] The embodiment of the present invention provides a method for preparing low-cost 1,4-naphthalenediol. Please refer to Figure 1 , including the following steps:

[0047] S1. Mixing step: Mix 1,4-naphthoquinone, a polar solvent and a catalyst to form a mixture.

[0048] It should be noted that the 1,4-naphthoquinone can be industrial-grade 1,4-naphthoquinone generated by continuous catalytic gas-phase oxidation of naphthalene, or 1,4-naphthoquinone obtained by oxidizing with an oxidant such as hydrogen peroxide or cerium in water or an organic solvent.

[0049] In step S1, the polar solvent is selected from one or more of alcohol solvents, diol solvents, ethylene glycol ether solvents, organic acids, organic acid esters, ether solvents, ketone solvents, and organic base solvents.

[0050] Specifically: the alcohol solvents include but are not limited to methanol, ethanol, and propanol; the diol solvents include but are not limited to ethylene glycol and propylene glycol; the ethylene glycol ether solvents include but are not limited to ethylene glycol monoether and diether; the organic acids include but are not limited to acetic acid and propionic acid; the ether solvents include but are not limited to tetrahydrofuran and dioxane; the ketone solvents include but are not limited to acetone and methyl ethyl ketone; the organic base solvents include but are not limited to pyridine, quinoline, formamide, and dimethylformamide.

[0051] The amount of the polar solvent used is 1 to 30 times the weight of 1,4-naphthalenediol.

[0052] Preferably, the amount of the polar solvent used is 1 to 10 times the weight of 1,4-naphthalenediol.

[0053] The catalyst is selected from one or more of palladium catalyst supported on activated carbon, platinum oxide, platinum colloid, copper chromite, ruthenium catalyst supported on activated carbon, and Raney nickel.

[0054] Preferably, the catalyst is palladium catalyst supported on activated carbon because it has better controllability for the hydrogenation of aromatic rings.

[0055] The amount of the catalyst used is 0.1 to 5 times the weight of 1,4-naphthoquinone, preferably 0.1 to 2 times.

[0056] S2. Feeding step: Feed the mixture into a microchannel tubular reactor.

[0057] In a specific example, a control system can be used to monitor the flow rate during the feeding process.

[0058] S3. Reaction step: In the microchannel tubular reactor, control the reaction temperature and reaction pressure, and introduce hydrogen to carry out a continuous catalytic hydrogenation reduction reaction.

[0059] Specifically:

[0060] The reaction temperature is from room temperature to 100 °C, preferably 20 - 90 °C; the reaction pressure is 1 - 15 atmospheres; the reaction residence time is 3.6 - 3600 seconds.

[0061] S4. Separation step: Separate the catalyst to obtain a reaction solution containing 1,4-naphthalenediol.

[0062] The separation process can adopt methods well-known to those skilled in the art such as filtration, which will not be elaborated here.

[0063] In addition, in another specific example, it further includes:

[0064] S5. Post-treatment step: adding a non-polar solvent to the reaction solution containing 1,4-naphthalenediol for crystallization, and separating to obtain the 1,4-naphthalenediol product.

[0065] Before adding the non-polar solvent, the reaction solution containing 1,4-naphthalenediol can also be concentrated to reach the optimal concentration.

[0066] The non-polar solvent is selected from one or more of aliphatic hydrocarbons, alicyclic hydrocarbons, and halogenated hydrocarbons.

[0067] Specifically:

[0068] Aliphatic hydrocarbons include but are not limited to hexane and heptane; alicyclic hydrocarbons include but are not limited to cyclohexane; halogenated hydrocarbons include but are not limited to chloroform, trichloroethane, trichloroethylene, and tetrachloroethane.

[0069] The dosage of the non-polar solvent is 0.5 - 30 times the weight of 1,4-naphthalenediol, preferably 1 - 5 times.

[0070] In a specific example, the temperature of the post-treatment step can be controlled below 100°C, preferably near room temperature.

[0071] In a specific example, to increase the yield of 1,4-naphthalenediol, crystallization separation can be carried out below 15°C, preferably at 0 - 10°C.

[0072] It should be noted that in the foregoing steps, it is essential to carry out under the protection of inert gases such as nitrogen.

[0073] In addition, please refer to Figure 2 , the embodiment of the present invention also provides a microchannel tubular reactor system for preparing 1,4-naphthalenediol, and this microchannel tubular reactor system specifically includes:

[0074] A metering tank for mixing 1,4-naphthoquinone, a polar solvent, and a catalyst;

[0075] A diaphragm metering pump connected to the metering tank;

[0076] A microchannel tubular reactor having a mixer inlet, and the mixer inlet is connected to the diaphragm metering pump;

[0077] A liquid hydrogen storage tank, and the liquid hydrogen storage tank is connected to the mixer inlet;

[0078] A control system for controlling the reaction temperature and reaction pressure.

[0079] In a specific example, the control system may be a DCS computer control system for monitoring parameters such as flow rate, temperature, pressure, and hydrogen quality.

[0080] Furthermore, 1,4-naphthalenediol prepared according to the foregoing preparation method and preparation system is easy to filter, the suspension formed by the non-polar solvent has good fluidity and is easy to use, the wet filter cake is easy to dry, the manufacturing process is easy, the dry product is difficult to oxidize during storage, and the storage property is good. The obtained product is white or silver-white, does not agglomerate, and the product has high purity and high yield. It can be widely used in the preparation of pharmaceutical intermediates, rubber additives, resin materials, dyes, or thermal recording materials.

[0081] In summary, the embodiments of the present invention by using a microchannel tubular reactor for continuous catalytic hydrogenation reduction have the following beneficial effects: significantly improving the reaction safety and reducing the safety risk; the crystallization is easy to filter, the product is white or silver-white, does not agglomerate, the product purity can reach 99.4%, and the product has good storage stability and is not easy to oxidize. Another advantage of the present invention is that high-purity and high-yield 1,4-naphthalenediol can still be manufactured using industrial 1,4-naphthoquinone containing impurities.

[0082] According to the above content of this embodiment, Experimental Examples 1 to 3 and Comparative Examples 1 to 2 are set, and five groups of experimental comparative tests are carried out respectively to test the product properties.

[0083] Experimental Example 1:

[0084] 35 kg of 98.2% 1,4-naphthoquinone, 120 L of methanol, and 800 g of 5% palladium-carbon catalyst containing 50% water were mixed evenly in a 200-L metering tank. After replacing the air in the metering tank with nitrogen, the liquid-solid two-phase mixed solution containing the compound of 1,4-naphthoquinone, methanol, and 5% palladium-carbon catalyst containing 50% water was pressurized by a diaphragm metering pump and transported to the inlet of the microchannel tubular reactor. The quality of hydrogen metered from the liquid hydrogen storage tank was controlled by a DCS computer, and at the same time, the ratio of the gas-liquid-solid three-phase mixture at the inlet of the microchannel tubular reactor was controlled, and the residence time in the microchannel tubular reactor was controlled to be 3.6 to 3600 seconds. When the three-phase mixture entered the microchannel tubular reactor, it was about 20°C. The temperature rise rate of the whole process of the microchannel tubular reactor was controlled by a DCS computer. After about 0.06 to 60 minutes, the temperature was 70 to 90°C, and a total of 5308 L of hydrogen was absorbed (converted to normal temperature and pressure). The reaction was stopped to complete the whole process of hydrogenation reduction reaction.

[0085] About 150 to 156 L of the solid-liquid two-phase mixture of the reaction product was taken out, and about 750 to 800 g of 5% palladium-carbon catalyst containing 50% water was recovered by hot filtration (for recycling).

[0086] The filtrate was concentrated by a rotary evaporator, about 110 liters of methanol was recovered. To the remaining methanol containing 1,4-naphthalenediol crystals, 60 liters of chloroform was added with stirring to form a suspension, and it was slowly cooled to 7 °C. It was filtered under nitrogen protection, the wet 1,4-naphthalenediol filter cake was taken out and dried in a 10-liter rotary evaporator to obtain 31.6 kg of 1,4-naphthalenediol product.

[0087] The particle size of the 1,4-naphthalenediol crystals was about 50×1000 μm, and the color was white. The melting point was 190.4 °C. The GC purity was 99.4%, and no other components were detected by HPLC. The prepared 1,4-naphthalenediol crystals were stored for 100 days, and the appearance and purity did not change.

[0088] Experimental Example 2:

[0089] Except that trichloroethylene was used instead of chloroform, other conditions were the same as in Experimental Example 1, and the obtained results were basically the same.

[0090] Experimental Example 3:

[0091] Using o-xylene instead of chloroform in Experimental Example 1, and other operations were the same as in Experimental Example 1, 32.6 kg of 1,4-naphthalenediol was obtained, with a melting point of 190 °C and a purity of 99.2%. The color of the crystal product was slightly yellow.

[0092] Experimental Example 4:

[0093] 35 kg of 1,4-naphthalenediol (purity about 94%) obtained by hydrogenation reduction of 1,4-naphthoquinone and vacuum drying was dissolved in 120 liters of methanol at 50 °C, then concentrated under reduced pressure, and about 110 liters of methanol was distilled off. The residue was added with 60 liters of chloroform at room temperature, stirred well, cooled to 7 °C, and filtered to crystallize.

[0094] 35.7 kg of 1,4-naphthalenediol was obtained, with a melting point of 190.4 °C and a purity of 99.4%.

[0095] Comparative Example 1:

[0096] Using the same raw material ratio and reaction conditions as in Experimental Example 1, the hydrogenation reduction reaction was carried out in a microchannel tubular reactor. After filtering out the catalyst under nitrogen protection, the filtrate was directly dried under reduced pressure.

[0097] Tar-like substances adhered to the obtained 1,4-naphthalenediol crystals, the appearance was brown, the melting point was 185 °C, and the purity was 94.2%.

[0098] Comparative Example 2:

[0099] The reaction solution of Experimental Example 1 was concentrated to contain 60% of 1,4-naphthalenediol, cooled, filtered under strict nitrogen protection, and dried to obtain 8.2 kg of 1,4-naphthalenediol, with a melting point of 190.1 °C and a purity of 99.1%.

[0100] The experimental results show that:

[0101] When continuously preparing 1,4-naphthalenediol by using a microchannel tubular reactor and treating it with chloroform or trichloroethylene as a non-polar solvent, a white crystal product with a purity of 99.4% and a melting point of 190.4 °C can be obtained, and the product has good stability, and there is no change in appearance and purity after being stored for 100 days; when using o-xylene as a non-polar solvent, although a product with a purity of 99.2% can be obtained, the product is slightly yellow. In contrast, if the non-polar solvent treatment step is omitted, the product purity is only 94.2%, and the appearance is brown with tarry substances attached to the surface; if directly concentrated and crystallized, although the product purity can reach 99.1%, the yield is significantly reduced. The above results confirm that the present invention uses a microchannel tubular reactor for continuous catalytic hydrogenation reduction and combines the combined treatment process of polar and non-polar solvents, which not only significantly improves the reaction safety and has low cost, but also can effectively improve the product quality and has good industrial application prospects.

[0102] The method for continuously preparing 1,4-naphthalenediol by using the microchannel tubular reactor provided by the embodiment of the present invention, through continuous catalytic hydrogenation reduction by using a microchannel tubular reactor and combining the combined treatment process of polar and non-polar solvents, makes the product crystallization easy to filter, the product is white, the purity can reach 99.4%, and it has good storage stability. The method of the present invention not only significantly improves the reaction safety and avoids the safety risks of the traditional batch process in a kettle, but also can process industrial-grade raw materials, has the advantages of good suspension fluidity and easy drying of wet filter cakes, and the process operation is simple and suitable for large-scale industrial production. The 1,4-naphthalenediol prepared by the present invention can be widely applied to fields such as pharmaceutical intermediates, rubber additives, resin materials, dyes, and thermal recording materials.

[0103] Example Two

[0104] The 1,4-naphthalenediol obtained according to the preparation method provided in Example One in the embodiment of the present invention is used to prepare a 1,4-naphthalene-structured polyaryletherketone homopolymer, including the following steps:

[0105] Add 1,4-naphthalenediol, 4,4'-difluorobenzophenone and potassium carbonate into an organic solvent; add an azeotropic agent; then heat and remove water in a gradient manner under nitrogen protection, and react at a temperature of 180 - 220 °C for 8 - 24 hours; after cooling, crush the obtained product and wash it; after drying, obtain a 1,4-naphthalene-structured polyaryletherketone homopolymer.

[0106] Wherein the molar ratio of the 1,4-naphthalenediol to the 4,4'-difluorobenzophenone is 0.8 - 1.2:1.

[0107] Preferably, the organic solvent is selected from one or more of sulfolane, N-methylpyrrolidone or dimethylacetamide.

[0108] Preferably, the azeotropic agent includes toluene or xylene. The azeotropic agent can form an azeotrope with the water generated in the reaction, promote the complete progress of the etherification reaction, and ensure the formation of high conversion rate and high molecular weight polymer.

[0109] In a specific example, 0.20 mol of 1,4-naphthalenediol, 0.20 mol of 4,4'-difluorobenzophenone and 0.24 mol of potassium carbonate were added to 180 mL of sulfolane; simultaneously, 90 mL of toluene was added as an azeotropic agent; under nitrogen protection, first, the temperature was increased gradiently in the range of 130-160 °C for 8 hours for water-carrying operation, so that the water generated during the reaction was completely removed by azeotropy; then the reaction temperature was raised to 200 °C and the reaction was continued for 12 hours to fully carry out the polymerization reaction; after the reaction was completed, the reaction system was cooled to room temperature to obtain a strip-shaped solid product; the obtained product was crushed and washed 3 times each with deionized water and absolute ethanol to remove residual inorganic salts and unreacted monomers; finally, it was dried in vacuum at 80 °C for 24 hours to obtain a light yellow powdery 1,4-naphthalene-structured polyaryletherketone homopolymer.

[0110] The glass transition temperature (Tg) of this polymer is 195 °C. The thermogravimetric analysis (TGA) results show that the 5% thermal weight loss temperature of this polymer exceeds 500 °C.

[0111] The polyaryletherketone homopolymer synthesized from 1,4-naphthalenediol in the examples of the present invention has a unique molecular structure. The presence of the 1,4-naphthalene group in the molecular structure can provide rich aromatic π electron clouds, which is beneficial to form a stable interface with carbon-based materials such as carbon nanotubes through π-π stacking interaction. This characteristic makes it have potential application value in the field of high-performance composite materials.

[0112] Compared with traditional modifiers, the 1,4-naphthalene-structured polyaryletherketone homopolymer can be widely used in thermoplastic composites, especially as a toughening agent for multi-walled carbon nanotubes and a sizing agent for thermoplastic carbon fibers. The 1,4-naphthalene group in its molecular structure can form a strong non-covalent bond with the surface of carbon nanotubes and carbon fibers through π-π interaction, providing better interfacial bonding strength; in addition, it has excellent compatibility with thermoplastic matrix resins such as polyetheretherketone (PEEK), etc., ensuring the continuity of the phase interface in the composite material system; the relatively high glass transition temperature and thermal stability ensure the performance stability of the composite material under high-temperature environments; as a toughening phase, it can effectively absorb and disperse stress, improving the toughness and impact resistance of the composite material.

[0113] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A method for preparing low-cost 1,4-naphthalene diol, characterized in that: The following steps are involved: combining 1,4-naphthoquinone, a polar solvent, and a catalyst to form a mixture; feeding the mixture into a microchannel tubular reactor; In the microchannel tubular reactor, the reaction temperature and reaction pressure are controlled, and hydrogen is introduced to carry out a continuous catalytic hydrogenation reduction reaction; The catalyst was separated to obtain a reaction solution containing 1,4-naphthalenediol.

2. The method according to claim 1, characterized in that: The polar solvent is selected from one or more of alcohol solvents, diol solvents, glycol ether solvents, organic acids, organic acid esters, ether solvents, ketone solvents, and organic base solvents. The amount of the polar solvent is 1-30 times the weight of 1,4-naphthalenediol.

3. The method according to claim 1, characterized in that: The catalyst is selected from one or more of activated carbon-supported palladium catalyst, platinum oxide, platinum colloid, copper chromite, activated carbon-supported ruthenium catalyst, and skeleton nickel; preferably, the amount of the catalyst is 0.1-5 times the weight of 1,4-naphthoquinone.

4. The method according to claim 1, characterized in that: The reaction residence time of the continuous catalytic hydrogenation reduction reaction is 3.6 to 3600 seconds, the reaction temperature is from room temperature to 100° C., and the reaction pressure is 1 to 15 atmospheres.

5. The method according to claim 1, characterized in that Post-processing steps are also included: Adding a non-polar solvent to the reaction solution containing 1,4-naphthalenediol for crystallization; Separate and obtain 1,4-naphthalenediol product; Preferably, before adding the non-polar solvent, the method further comprises the step of concentrating the reaction solution containing 1,4-naphthalenediol; More preferably, the non-polar solvent is selected from one or more of aliphatic hydrocarbons, alicyclic hydrocarbons or halogenated hydrocarbons, and the amount of the non-polar solvent used is 0.5-30 times the weight of 1,4-naphthalenediol.

6. A preparation system for preparing 1,4-naphthalene diol, characterized in that: include: Metering tank for mixing 1,4-naphthoquinone, polar solvent and catalyst; a diaphragm metering pump connected to the metering tank; a microchannel tubular reactor having a mixer inlet, wherein the mixer inlet is connected to the diaphragm metering pump; A liquid hydrogen storage tank connected to an inlet of the mixer; Control system used to control reaction temperature and reaction pressure.

7. 1,4-naphthalenediol prepared by the method according to any one of claims 1 to 5.

8. Use of the 1,4-naphthalene diol according to claim 7 in the preparation of pharmaceutical intermediates, rubber additives, resin materials, dyes or thermal recording materials.

9. A method for preparing 1,4-naphthalene structured polyaryletherketone homopolymer by using 1,4-naphthalenediol as claimed in claim 7, characterized in that: The following steps are involved: adding 1,4-naphthalenediol, 4,4'-difluorobenzophenone and potassium carbonate into an organic solvent; Adding an azeotropic agent; Under nitrogen protection, the temperature is increased to 180-220°C with water gradient and the reaction time is 8-24 hours; After cooling, the obtained product is crushed and then washed; After drying, a 1,4-naphthalene structured polyaryletherketone homopolymer is obtained; The molar ratio of 1,4-naphthalene diol to 4,4'-difluorobenzophenone is 0.8-1.2:1; Preferably, the organic solvent is selected from one or more of sulfolane, N-methylpyrrolidone or dimethylacetamide; Preferably, the azeotropic agent comprises toluene or xylene.

10. A 1,4-naphthalene structured polyaryletherketone homopolymer prepared by the method according to claim 9.

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