Method for preparing bio-based adipic acid

Abstract

The present invention relates to a method for preparing bio-based adipic acid. In the method, by using a nickel-based hydrogenation catalyst provided by the present invention, when the concentration of a substrate reaches up to 200 g / L, the reaction of bio-based sodium muconate with hydrogen is catalyzed in a batch reactor and a micro-packed bed to prepare sodium adipate, the yield of the target product being approximately 100 mol%. The bio-based sodium muconate is bio-based sodium muconate obtained by microbial fermentation. The method has the advantages of a short reaction path, good economical efficiency and being conducive to large-scale preparation, and lays a solid foundation for the industrialization of the green synthesis of bio-based adipic acid.

Description

Process for the preparation of a bio-based adipic acid TECHNICAL FIELD

[0001] The present invention belongs to the field of bio-based chemicals, and relates to a catalytic process for the preparation of a bio-based adipic acid (AdA). BACKGROUND

[0002] Adipic acid is a dicarboxylic acid containing 6 carbon atoms, widely used in the production of nylon 6.6, engineering plastics and biodegradable plastics PBAT, etc. The Asia-Pacific region is not only the largest market for adipic acid, but also the fastest growing market for adipic acid demand. From 2014 to 2020, the average annual growth rate of adipic acid consumption was about 5.3%. The global market capacity of adipic acid in 2012 was 2.61 million tons. By the end of December 2020, the total production capacity of adipic acid worldwide was about 4.908 million tons. At present, adipic acid is still generally produced by petrochemical route. The traditional synthesis method of adipic acid is cyclohexane oxidation process using benzene as raw material, and the adipic acid production capacity accounts for about 90% of the world's total production capacity. After the cyclohexane oxidation process using benzene as raw material, the nitric acid is reduced to nitrogen oxides, causing great pollution. 10% of the global nitrogen pollution is discharged by adipic acid synthesis plants, and its greenhouse climate impact is 298 times higher than that of CO2. The use of green renewable raw materials to produce bio-adipic acid can effectively reduce environmental pollution. With the proposal of the carbon peak and carbon neutralization target, the traditional chemical synthesis process of adipic acid needs to be eliminated urgently, and the development of green bio-based adipic acid production process is imminent, which is the focus of attention of the academic and industrial communities around the world.

[0003] The current green synthesis process of adipic acid mainly includes: 1) whole biosynthesis method, the methods that have been proven to be feasible include reverse adipic acid degradation pathway, β-oxidation or reverse β-oxidation combined with ω-oxidation pathway, 2-oxoheptanedioic acid pathway; 2) semi-biosynthesis method, first obtain the precursor by biological fermentation, such as cis, cis-muconic acid, etc., and then convert it into adipic acid by chemical catalytic method. Since the related process of preparing muconic acid by biological fermentation is very mature, the concentration of the product muconic acid has more advantages than that of adipic acid directly fermented by the former, so the latter is recognized as a technology with more industrialization prospects.

[0004] Cis, cis-muconic acid (CCMA) is a diunsaturated dicarboxylic acid with six carbon atoms. In the presence of a heterogeneous catalyst, muconic acid can be hydrogenated to adipic acid in a reductive atmosphere. A similar technique was first reported by Karen M. Draths and John W. Frost (Karen M. Draths, John W. Frost. Environmentally compatible synthesis of adipic acid from D-glucose [J]. Journal of the American Chemical Society, 1994, (116): 399-400.) in 1994, who catalytically hydrogenated about 2.5 g / L of cis-muconic acid to achieve a 90% yield under mild reaction conditions. Current research has mainly focused on the use of noble metal (Pd, Pt, etc.) catalysts for the catalytic hydrogenation of muconic acid in organic solvents; for example, Draths and Niu et al. (W. Niu, K. M. Draths, J. W. Frost, Benzene-free synthesis of adipic acid, Biotechnology Progress. 18 (2002) 201-211) studied the catalytic hydrogenation of muconic acid using a Pt catalyst (10 wt%): after 2.5 hours, the molar yield of adipic acid was 90%-97%. However, the reaction substrate concentration was low (0.15 mol / L) and harsh operating conditions were used, such as a H2 pressure of 3.4 MPa. Thomas et al. (Raja R, Thomas J M, Xu M, et al. Highly efficient one-step conversion of cyclohexane to adipic acid using single-site heterogeneous catalysts [J]. Chemical Communications, 2006, (4): 448-450.) also obtained quantitative hydrogenation of muconic acid to adipic acid using a higher pressure of hydrogen gas (3 MPa); in addition, they successfully tested some Ru bimetallic nanocatalysts supported on mesoporous silica.

[0005] Although the existing literatures on the preparation of adipic acid from muconic acid by hydrogenation have obtained high yield, there are still the following serious challenges: (1) most of them use noble metal (Pd, Pt, etc.) catalysts, and the expensive price of noble metal is difficult to meet the principle of industrial economy; (2) organic solvents (ethanol, amyl alcohol, etc.) are used as solvents in the hydrogenation reaction, and the degree of greenness is insufficient; (3) low substrate concentration, generally not more than 10 g / L, which reduces the production intensity of the unit volume reactor, and the separation energy consumption is huge, which cannot realize industrialization; (4) the existing literatures all complete the hydrogenation process in a stirred tank (gas-liquid-solid three-phase reaction), which brings the following problems: first, the gas-liquid dispersion mode is mechanical stirring, and the dispersion of gas is poor, the specific surface area of gas-liquid two-phase contact is only 200-2000 m 2 / m 3 , and the overall gas-liquid volumetric mass transfer coefficient is in the range of 1.27×10 -2 -15.40×10 -2 s -1 , even under the condition of high-speed stirring of 1000 rpm, the hydrogenation process still has the characteristics of gas-liquid mass transfer control, which means that the interfacial mass transfer behavior has a great influence on the apparent kinetics, and a long reaction time is required (Yue Jun, Chen Guangwen, Yuan Quan, Luo Lingai, Gonthier Yves, Hydrodynamics and mass transfer characteristics in gas-liquid flow through a rectangular microchannel. Chemical Engineering Science, 2007, 62, 2096-2108.; Yawalkar Archis A, Heesink Albertus BM, Versteeg Geert F, Pangarkar Vishwas G, Gas-Liquid Mass Transfer Coefficient in Stirred Tank Reactors. The Canadian Journal of Chemical Engineering, 2002, 80, 840-848.); second, hydrogen is one of the reactants, and hydrogen is flammable and explosive, and the explosion limit range is very wide, which increases the safety hazard of the process; finally, it cannot be operated continuously, which is not conducive to the realization of industrial production.

[0006] At present, the low reaction substrate concentration and high hydrogen pressure make it difficult to realize the industrialized production of bio-based adipic acid, which has been a technical problem that the skilled in the art has been trying to solve for a long time but cannot solve. SUMMARY

[0007] One of the purposes of the present application is to provide a nickel-based hydrogenation catalyst for preparing bio-based adipic acid, which has the advantages of economic cheapness and high catalytic activity and high selectivity compared with traditional noble metal catalysts.

[0008] The second purpose of the present application is to provide a preparation method of the above-mentioned nickel-based hydrogenation catalyst, which can prepare a nickel-based hydrogenation catalyst with high catalytic activity and high selectivity by controlling the reaction conditions, and can realize the industrialized production of bio-based adipic acid with high yield (100 mol%) at high substrate concentration (200 g / L).

[0009] The third purpose of the present application is to provide a production method of bio-based adipic acid, which replaces the traditional noble metal catalyst with an economic and cheap nickel-based hydrogenation catalyst, and can efficiently realize the hydrogenation reaction in the preparation process of bio-based adipic acid in a high-efficiency, safe and continuous production reaction system with industrial value, which can meet the requirements of large-scale production of bio-based adipic acid.

[0010] To this end, the first aspect of the present application provides a nickel-based hydrogenation catalyst for preparing bio-based adipic acid, which is composed of a carrier loaded with metallic nickel.

[0011] In some embodiments of the present application, the average particle size of the metallic nickel is 2.5-4.5 nm, and the specific surface area of the nickel-based hydrogenation catalyst is 50-300 m 2 / g;

[0012] In some embodiments of the present application, the loading amount of metallic nickel in the nickel-based hydrogenation catalyst is 2wt%-40wt%.

[0013] The second aspect of the present application provides a preparation method of a nickel-based hydrogenation catalyst, which comprises carrier pretreatment and loading of metallic nickel by a precipitation-deposition method, which comprises:

[0014] Step A: ultrasonically pretreating the carrier in a Na2CO3 aqueous solution, and after solid-liquid separation, drying to obtain a pretreated carrier;

[0015] Step B: ultrasonically treating the pretreated carrier in water to obtain a carrier suspension;

[0016] Step C: mixing a nickel source with urea and water to obtain a nickel source-urea mixture;

[0017] Step D: mixing the carrier suspension with the nickel source-urea mixture, sealing and stirring for impregnation, then opening the seal and stirring for drying until the moisture is completely volatilized, to obtain a dried nickel-based hydrogenation catalyst precursor;

[0018] Step E, high temperature reduction of the dried nickel-based hydrogenation catalyst precursor in a hydrogen atmosphere to obtain a nickel-based hydrogenation catalyst.

[0019] In some embodiments of the present application, the concentration of the aqueous Na2CO3 solution is 0.1-0.8 M, and the mass ratio of the aqueous Na2CO3 solution to the carrier is 5-15:1.

[0020] In some embodiments of the present application, in step C, the molar ratio of the urea to the nickel source is 2-8.

[0021] In some embodiments of the present application, in step C, the mass ratio of the nickel source to water is 0.01-0.1.

[0022] In some embodiments of the present application, in step D, the mass ratio of the pretreated carrier to the nickel source is 0.65-10.

[0023] In some embodiments of the present application, the concentration of the carrier suspension is 20-100 g / L.

[0024] According to the present application, in steps A and B, the time of the ultrasonic is 0-60 min.

[0025] In some embodiments of the present application, in step D, the temperature of the impregnation is 30-100℃; and the time of the impregnation is 2-6 h.

[0026] In some embodiments of the present application, in step D, the temperature of the steam drying is 30-100℃.

[0027] In some embodiments of the present application, in step E, the temperature of the high temperature reduction is 300-1000℃; and the time of the high temperature reduction is 60-300 min.

[0028] The third aspect of the present application provides a hydrogenation reaction system for preparing bio-based adipic acid, which comprises a batch stirring reaction kettle or a micro-reaction device.

[0029] According to the present application, the micro-reaction device comprises, in sequence, a reaction liquid storage tank, an advection pump, a micro-mixer, a micro-packed bed reactor, a phase separator, and a product collector, a hydrogen source is connected to the micro-mixer, a gas flow meter is arranged between the hydrogen source and the micro-mixer, and a back pressure valve is arranged on the phase separator.

[0030] In some embodiments of the present application, the inner diameter of the micro-packed bed reactor is 0.5-10 mm.

[0031] In some embodiments of the present application, the length of the micro-packed bed reactor is 2-20 cm.

[0032] The fourth aspect of the present application provides a method for preparing bio-based adipic acid, which comprises carrying out a hydrogenation reaction on bio-based muconic acid or sodium muconate in the presence of the nickel-based hydrogenation catalyst as described in the third aspect of the present application or the nickel-based hydrogenation catalyst prepared by the method as described in the second aspect of the present application in the hydrogenation reaction system as described in the first aspect of the present application to prepare adipic acid.

[0033] According to some embodiments of the present application, when the hydrogenation reaction system comprises a batch stirred tank reactor, the method for preparing bio-based adipic acid comprises placing the nickel-based hydrogenation catalyst into the batch stirred tank reactor, adding an aqueous solution of bio-based muconic acid or sodium muconate, and charging hydrogen gas to carry out a hydrogenation catalytic reaction to obtain adipic acid.

[0034] In some embodiments of the present application, when a batch stirred tank reactor is used for the reaction, the concentration of the aqueous solution of bio-based muconic acid or sodium muconate is ≥10 g / L.

[0035] In some embodiments of the present application, when a batch stirred tank reactor is used for the reaction, the mass ratio of bio-based muconic acid or sodium muconate to the nickel-based hydrogenation catalyst is 1-50.

[0036] According to the present application, the pressure of hydrogen gas in the batch stirred tank reactor is 0.1-5 MPa.

[0037] In some embodiments of the present application, when a batch stirred tank reactor is used for the reaction, the temperature of the hydrogenation reaction is 50-200℃.

[0038] In some embodiments of the present application, when a batch stirred tank reactor is used for the reaction, the time of the hydrogenation reaction is 5 min-24 h.

[0039] According to some embodiments of the present application, when the hydrogenation reaction system comprises a micro-reactor device, the nickel-based hydrogenation catalyst is filled into a micro-packed bed reactor, an aqueous solution of muconic acid or sodium muconate and hydrogen gas are introduced into the micro-packed bed reactor, and the micro-packed bed reactor is heated by water bath or oil bath to carry out a catalytic hydrogenation reaction to obtain adipic acid.

[0040] According to the present application, when a micro-reactor device is used for the reaction, filling the nickel-based hydrogenation catalyst into a micro-packed bed reactor comprises first compressing and molding a powder-shaped nickel-based hydrogenation catalyst prepared from a powder-shaped carrier into tablets, sieving, and then filling into the micro-packed bed reactor, or directly filling a spherical hydrogenation catalyst prepared from a spherical carrier into the micro-packed bed reactor.

[0041] In some embodiments of the present application, when a micro-reactor device is used for the reaction, the height of the filled catalyst bed layer is 2-15 cm; and the both ends of the filled catalyst bed layer are filled with inert glass beads.

[0042] In some embodiments of the present application, when the micro-reaction device is used for reaction, the molar concentration of the aqueous solution of bio-based muconic acid or the aqueous solution of sodium muconate is greater than or equal to 10 g / L.

[0043] In some embodiments of the present application, when the micro-reaction device is used for reaction, the flow rate of the aqueous solution of bio-based muconic acid or the aqueous solution of sodium muconate is 0.1-2 mL / min.

[0044] In some embodiments of the present application, when the micro-reaction device is used for reaction, the pressure of the hydrogen gas introduced into the micro-packed bed reactor is 0.16-10.0 MPa; the flow rate of the hydrogen gas is 10-100 mL / min.

[0045] In some embodiments of the present application, when the micro-reaction device is used for reaction, the temperature of the hydrogenation reaction is 30-200℃.

[0046] In some embodiments of the present application, when the micro-reaction device is used for reaction, the time of the hydrogenation reaction is 10 s-10 min.

[0047] According to the present application, the preparation method comprises hydrogenation of the aqueous solution of muconic acid to obtain an aqueous solution of adipic acid, and then cooling to precipitate the solid adipic acid; or hydrogenation of the aqueous solution of sodium muconate to obtain an aqueous solution of sodium adipate, and then acidification by dropwise addition of an inorganic acid, and then cooling to precipitate the solid adipic acid.

[0048] The present application improves the existing semi-biological adipic acid preparation process which is difficult to realize large-scale production. On the one hand, the alkali treatment of muconic acid is changed to sodium muconate; on the other hand, a new nickel-based catalyst preparation process is innovatively proposed and designed, which greatly improves the dispersion of the active metal components in the catalyst, thereby improving the catalytic performance, and makes it possible to industrialize the catalytic hydrogenation of adipic acid with its low price advantage, changes the cost problem caused by the use of noble metal catalysts all the time, and greatly reduces the industrial application cost. Through the above two strategies, high target product yield is realized under high substrate concentration, which lays a solid foundation for the industrialized production of bio-based adipic acid.

[0049] The present application first proposes and realizes the use of self-made nickel-based catalyst to catalyze the high-concentration bio-based sodium muconate from biomass to prepare sodium adipate by high-selectivity hydrogenation in a batch reaction kettle and a micro-packed bed. When the concentration is as high as 200 g / L, the yield of sodium adipate can reach 100 mol%, which is nearly 20 times higher than the reported value. This method has the advantages of short reaction path, simple operation, good economy, environmental protection, and easy large-scale preparation, and provides advanced technical support for the industrialized production of bio-based adipic acid, and has broad application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0050] The application will be described in further detail below with reference to the drawings.

[0051] Figure 1 shows a catalyst synthesis scheme designed according to the reaction mechanism.

[0052] Figure 2 shows a reaction process for preparing adipic acid (sodium) based on catalytic hydrogenation of muconic acid (sodium); wherein R = H or Na.

[0053] Figure 3 shows a schematic diagram of a micro-reactor device in the application.

[0054] Figure 4 shows a TEM characterization particle size comparison diagram of the nickel-based catalyst prepared in Example 1 and the nickel-based catalyst prepared using the traditional impregnation method (the two catalysts only differ in the preparation method, and the rest are consistent), wherein the left graph is a particle size statistical diagram of the nickel-based catalyst prepared in the application; and the right graph is a particle size statistical diagram of the catalyst prepared using the traditional impregnation method.

[0055] Figure 5 is a schematic diagram of the process flow for producing bio-based adipic acid in the application. DETAILED DESCRIPTION

[0056] In order to facilitate easy understanding of the application, the application will be described in detail below with reference to the drawings. However, before the detailed description of the application, it should be understood that the application is not limited to the specific embodiments described. The described embodiments are only a part of the embodiments of the application, and are not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the application, and it should be understood that the terms used herein are only for describing the specific embodiments, and do not represent limitations.

[0057] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present application, the preferred methods and materials are now described.

[0058] I. Terms

[0059] The term "bio-based muconic acid" used in the application refers to cis-muconic acid converted from biomass raw materials, or cis-muconic acid prepared from biomass raw materials, compared with "muconic acid" prepared by traditional biochemical methods.

[0060] The term "semi-bio-based adipic acid preparation process" used in the application refers to the latter half of the chemical catalysis part in which cis-bio-based muconic acid sodium is converted into sodium adipate using a chemical catalysis method after the cis-bio-based muconic acid sodium is produced as an intermediate by biological fermentation.

[0061] The term "bio-based adipic acid" as used herein refers to adipic acid converted from the above bio-based muconic acid.

[0062] The term "micro packed bed" as used herein refers to a microfluidic device composed of a 314L stainless steel pipe as the main body, a micro splitter designed and made by the inventor, a micro packed bed, and a micro phase separator, as shown in Figure 3.

[0063] The term "nickel-based hydrogenation catalyst" as used herein refers to a solid hydrogenation catalyst prepared by a precipitation-deposition method using a nickel source and an alumina and SBA-15 carrier; wherein the "solid hydrogenation catalyst" refers to a solid substance that can change the chemical reaction rate (increase or decrease) of the reactants without changing the chemical equilibrium in a chemical reaction, and the mass and chemical properties of which do not change before and after the chemical reaction.

[0064] The term "water" as used herein, without specific description or limitation, refers to deionized water, purified water, distilled water, etc.

[0065] II. Embodiments

[0066] Adipic acid, as an important bulk chemical, plays an important role in modern industry. With the proposal of the carbon peak and carbon neutralization targets, the traditional chemical synthesis process of adipic acid needs to be eliminated urgently. However, the existing new production processes such as the full biological synthesis and the semi-biological synthesis of adipic acid cannot meet the requirements of industrialization. The inventor has found that the full biological method needs to be gradually modified for microorganisms, and the industrialization is far away. The semi-biological chemical catalysis method is limited by expensive noble metal catalysts and low catalytic concentration, which is difficult to meet the requirements and achieve industrial production. At present, the low substrate concentration and high hydrogen pressure make it difficult to achieve the industrialization of bio-based adipic acid, which is a technical problem that has been long sought but not solved by those skilled in the art. In view of this, the inventor has conducted a lot of research on the preparation technology of adipic acid.

[0067] The inventor has found that the key point of industrialization of adipic acid is high yield at high substrate concentration. The above two "highs" can ensure low energy consumption of reaction and separation, which means low production cost: (1) high substrate concentration means small reactor volume, low investment, and high production intensity; (2) high yield at high substrate concentration means high concentration of target product, which means low separation cost. There have been reports that the substrate concentration of muconic acid is low (≤10 g / L) and cannot be industrialized. Maintaining a low substrate (muconic acid) concentration is because the reactant itself has acidity and catalytic performance, that is, under heating conditions, muconic acid itself will act as a catalyst and undergo a series of side reactions through "autocatalysis". Therefore, the "necking" technical difficulty of bio-based adipic acid preparation lies in how to increase the substrate concentration and obtain high target product yield.

[0068] In order to solve the above-mentioned technical difficulties of "necking", the application innovatively proposes the idea of using high-efficiency nickel-based hydrogenation catalyst to catalyze the hydrogenation of sodium muconate to prepare adipic acid, that is, two key points of "high-efficiency catalyst" and "sodium muconate": the alkali treatment of muconic acid to obtain the corresponding salt can eliminate the acidic characteristics of the reactant itself, and ingeniously solve the problem of self-catalysis caused by the carboxylic acid group of the reactant, laying a foundation for improving the substrate concentration; the special catalyst preparation method obtains a high-efficiency catalyst (not only high activity, but also high selectivity), which ensures that only the two C=C double bonds are hydrogenated in the reaction process, and avoids the hydration of C=C double bond and other side reactions, and realizes high yield of the target product.

[0069] Further, the present inventors have found through a large amount of research that the hydrogenation reaction of muconic acid requires that the catalyst has good adsorption and desorption capacity and also has excellent hydrogen activation and dissociation capacity. After screening, a neutral carrier is selected, which should have good adsorption of the substrate and desorption of the product. It is found through testing that alumina and SBA-15 have good carrier performance. For the selection of active metals, considering economy, nickel is selected as the loaded active metal, and a nickel-based hydrogenation catalyst is innovatively constructed. Metal nickel is selected as the active component to replace noble metals, and nickel metal is loaded by a precipitation-deposition method. The preparation method of the nickel-based hydrogenation catalyst specifically comprises:

[0070] (1) carrier pretreatment: the carrier is placed in a 0.1-0.8 M Na2CO3 aqueous solution for ultrasonic pretreatment for 0-60 min, preferably 10-60 min, and after solid-liquid separation, the carrier is dried to obtain a pretreated carrier;

[0071] (2) the pretreated carrier is placed in a flask and added with deionized water for ultrasonic treatment for 0-60 min, preferably 10-60 min, to obtain a carrier suspension with a concentration of 20-100 g / L, preferably 50-100 g / L;

[0072] (3) the nickel source is mixed with urea and deionized water to obtain a nickel source-urea mixture, the molar ratio of urea to nickel source is 2-8, and the mass ratio of nickel source to water is 0.01-0.1;

[0073] (4) according to the isoelectric point of the carrier, the carrier suspension and the nickel source-urea mixture are mixed in an amount of 0.65-10 of the mass ratio of the pretreated carrier to the nickel source, and impregnated at 30-100℃ for 2-6h, preferably 4-6h, more preferably 4h, and then the flask is opened and stirred at 30-100℃, preferably 90-100℃, more preferably 90℃, until the water is completely volatilized, to obtain a dried nickel-based catalyst precursor;

[0074] (5) The dry nickel-based catalyst precursor is put into a tube furnace in a hydrogen atmosphere and subjected to high-temperature reduction at 300-1000℃ for 60-300min, and the nickel-based hydrogenation catalyst obtained after reduction is stored in vacuum.

[0075] In the step (1), the mass ratio of the Na2CO3 aqueous solution to the carrier is 5-15:1.

[0076] In the present application, the carrier comprises one or more of alumina powder, alumina small spheres with a particle size of 20-100 mesh, SBA-15, silica gel, SiO2, TiO2 and activated carbon; preferably, the alumina powder comprises one or more of alpha alumina, gamma alumina and theta alumina.

[0077] In the present application, the nickel source comprises various nickel sources such as nickel acetate and / or nickel nitrate.

[0078] In the above preparation method, the catalyst is reduced after impregnation. It should be noted that the drying step after the completion of catalyst impregnation can be optionally operated in various ways such as air drying, oven drying and steam drying.

[0079] The nickel-based hydrogenation catalyst for preparing bio-based adipic acid prepared by the above preparation method is composed of a carrier loaded with metal nickel, and the nickel-based hydrogenation catalyst provided by the present application is shown in the action schematic diagram of Fig. 1.

[0080] The nickel-based hydrogenation catalyst prepared by the above method is characterized by BET and TEM, and the detection results show that the average particle size of the metal nickel in the nickel-based hydrogenation catalyst is 2.5-4.5nm, preferably 3.2-4.5nm, more preferably 3.2nm, the specific surface area of the nickel-based hydrogenation catalyst is 50-300m 2 / g, preferably 106.47-300m 2 / g, more preferably 106.47m 2 / g, and the loading amount of the metal nickel in the nickel-based hydrogenation catalyst is between 2wt%-40wt%, which proves that the metal nickel is highly dispersed on the surface of the catalyst carrier, thereby improving the catalytic performance, and an economical and efficient nickel-based hydrogenation catalyst is obtained.

[0081] The research results show that, compared with other existing catalytic active metals (such as noble metals Pt and Pd), nickel has good interaction with hydrogen, and the cost is 1 / 3000 of Pt and 1 / 1800 of Pd, which is more valuable for industrialization.

[0082] The nickel-based catalyst provided by the application is compared with the catalyst prepared by using the traditional impregnation method, and the relevant TEM characterization chart is shown in Figure 4. In Figure 4, the left chart is the nickel-based catalyst prepared by using the improved method of the application, and the right chart is the catalyst prepared by using the traditional impregnation method. It can be obviously observed that the catalyst prepared by using the method of the application has a uniform distribution of loaded metal, and the average particle size is only about half of that of the catalyst prepared by using the traditional method, and has a higher dispersion, which also explains the superior hydrogenation performance.

[0083] In the application, it should be understood that cis-mucobromic acid is extremely difficult to dissolve at room temperature, and can be considered as insoluble at room temperature. With the increase of temperature, the solubility is improved, but is extremely limited. When the temperature is increased to 70 DEG C, the solubility of mucobromic acid in water is only about 70 g / L. Therefore, mucobromic acid can be directly used as a reactant in some low-concentration experiments, but sodium mucobromate must be used as a substrate in higher-concentration reactions. In addition, in the fermentation of bio-based mucobromic acid, the product obtained due to the need of pH regulation (usually sodium hydroxide) is often cis-sodium mucobromate. Therefore, using sodium mucobromate as a substrate is beneficial to better docking the upstream process. Bio-based mucobromic acid refers to bio-based mucobromic acid obtained by separating and purifying the fermentation broth obtained by microbial fermentation. The hydrogenation reaction path of cis-mucobromic acid is shown in Figure 2.

[0084] In order to realize the production of bio-based adipic acid, the application further provides a hydrogenation reaction system for preparing bio-based adipic acid, and the main reaction device is a batch stirring reaction kettle or a micro-reaction device.

[0085] In the application, the micro-reaction device for preparing adipic acid by catalyzing the hydrogenation of bio-based sodium mucobromate by using the above-mentioned nickel-based hydrogenation catalyst is shown in Figure 3. As shown in Figure 3, the micro-reaction device comprises, in sequence, a reaction liquid storage tank, a laminar flow pump, a micro-mixer, a micro-packed bed reactor, a phase separation device and a product collector. The hydrogen source is connected to the micro-mixer, and a gas flow meter is arranged between the hydrogen source and the micro-mixer. A back pressure valve is arranged on the phase separator.

[0086] In the application, the micro-packed bed reactor can adopt a steel pipe with an inner diameter of 0.5-10 mm, preferably 0.5-3 mm, and a length of 2-20 cm, preferably 3-12 cm.

[0087] The application further provides an industrially promising preparation method of bio-based adipic acid, which comprises carrying out a hydrogenation reaction on bio-based mucobromic acid or bio-based sodium mucobromate in the above-mentioned hydrogenation reaction system of the application and in the presence of the above-mentioned nickel-based hydrogenation catalyst of the application to prepare adipic acid.

[0088] According to some embodiments of the present application, when the main reaction device of the hydrogenation reaction system is a batch stirred tank reactor, the method for preparing the bio-based adipic acid comprises placing a nickel-based hydrogenation catalyst into the batch stirred tank reactor, adding a bio-based muconic acid aqueous solution or a sodium muconate aqueous solution, filling the batch stirred tank reactor with hydrogen, and performing a hydrogenation catalytic reaction on a matching heating jacket to obtain adipic acid.

[0089] The reaction conditions for preparing adipic acid using a batch stirred tank reactor are as follows:

[0090] (1) The concentration of the bio-based muconic acid aqueous solution or the sodium muconate aqueous solution is ≥10 g / L, and is preferably 50-200 g / L;

[0091] (2) The mass ratio of the bio-based muconic acid or sodium muconate to the nickel-based hydrogenation catalyst is 1-50, and is preferably 20-40;

[0092] (3) The pressure of the hydrogen in the batch stirred tank reactor is 0.1-5 MPa, and is preferably 0.8-1.5 MPa;

[0093] (4) The temperature of the hydrogenation reaction is 50-200°C, and is preferably 70-90°C; and the time of the hydrogenation reaction is 5 min-24 h, and is preferably 30 min-6 h.

[0094] According to other embodiments of the present application, when the main reaction device of the hydrogenation reaction system is a microreaction device, the reaction process flow diagram for preparing adipic acid using a microreaction device is shown in FIG. 5, and the method for preparing the bio-based adipic acid comprises filling a nickel-based hydrogenation catalyst into a steel pipe as a micro packed bed reactor, filling inert materials (such as inert glass beads) at both ends of the steel pipe to prevent the catalyst from leaking out, introducing a muconic acid aqueous solution or a sodium muconate aqueous solution and hydrogen into the micro packed bed reactor, heating the micro packed bed reactor in a water bath or an oil bath, performing a catalytic hydrogenation reaction, collecting the liquid product, and performing a refining process (such as cooling or acidification and cooling) to separate the liquid product to obtain an adipic acid product.

[0095] According to the present application, when a microreaction device is used for the reaction, the filling of the nickel-based hydrogenation catalyst into the micro packed bed reactor comprises first pressing and molding a powder-shaped nickel-based hydrogenation catalyst prepared from a powder-shaped carrier into tablets, sieving the tablets, and then filling the tablets into the micro packed bed reactor, or directly filling a spherical hydrogenation catalyst prepared from a spherical carrier into the micro packed bed reactor. The height of the filled catalyst bed layer is 2-15 cm, and is preferably 3-10 cm; and the both ends of the filled catalyst bed layer are filled with inert glass beads.

[0096] The reaction conditions for preparing adipic acid using a microreaction device are as follows:

[0097] (1) the molar concentration of the aqueous solution of bio-based muconic acid or sodium muconate is greater than or equal to 10 g / L, preferably 50-200 g / L;

[0098] (2) the flow rate of the aqueous solution of bio-based muconic acid or sodium muconate is controlled by using a laminar flow pump, and the preferred flow rate is 0.1-2 mL / min;

[0099] (3) the pressure of the hydrogen gas fed into the micro packed bed reactor is 0.16-10.0 MPa, preferably 0.5-5.0 MPa;

[0100] (4) the flow rate of the hydrogen gas is controlled by using a gas flow meter, and the preferred flow rate of the hydrogen gas is 10-100 mL / min;

[0101] (5) the temperature of the hydrogenation reaction is 30-200℃, preferably 30-120℃; and the time of the hydrogenation reaction is 10 s-10 min, preferably 20 s-4 min.

[0102] In the present application, the bio-based muconic acid is prepared by fermentation.

[0103] The present application first applies the micro packed bed technology to the catalytic hydrogenation reaction of muconic acid, and achieves the complete conversion of bio-based sodium muconate with a concentration as high as 200 g / L into adipic acid in a reactor within 18 h. In a micro reactor, the yield of the target product sodium adipate is 100 mol% when the residence time is about 3 min and the concentration of the substrate solution (sodium muconate solution) is as high as 200 g / L. The space-time yield is increased by nearly 20 times compared with the reactor, and the reaction solvents of the two reactors are both water, which greatly improves the green degree of the reaction process.

[0104] III. Examples

[0105] The present application is specifically described below through specific examples. The experimental methods described below are all conventional laboratory methods unless otherwise specified. The experimental materials described below are all available from commercial channels unless otherwise specified.

[0106] The following examples include the preparation of catalysts and hydrogenation reaction processes. The nickel-based catalysts synthesized under different conditions in the following examples are characterized by TEM, and the average particle size is between 2.5-4.5 nm. After BET characterization, the specific surface area of the synthesized nickel-based catalysts is between 50-300 m 2 / g with good dispersity:

[0107] In the following examples, the reaction liquid component liquid product is determined by high performance liquid chromatography; the liquid product is analyzed using a Rezex-ROA organic acid H+column (300x7.8mm, Phenomenex) at 393K and a flow rate of the mobile phase equal to 0.06mL / min. A 5 millimolar aqueous sulfuric acid solution is selected as the mobile phase to elute the sample. The entire analysis lasts 40 minutes. The organic acid concentration is quantified by a refractive index detector (RID) using an external standard calibration method, and the raw material conversion rate, catalyst selectivity and adipic acid yield are calculated by the following formulas (I) to (III), respectively. Conversion rate X(%) = 100% x [(n0-n1) / n0] Formula (I)

[0108] In formula (I):

[0109] n0 is the initial mass of the added biobased sodium muconate, in g;

[0110] n1 is the mass of the biobased sodium muconate remaining after the reaction is completed, in g. Conversion rate S(%) = 100% x [n AdA / (n0-n1)] Formula (II)

[0111] In formula (II):

[0112] n0 is the initial mass of the added biobased sodium muconate, in g;

[0113] n1 is the mass of the biobased sodium muconate remaining after the reaction is completed, in g;

[0114] n AdA is the mass of the product sodium adipate after the reaction is completed, in g. Conversion rate Y(%) = 100% x (n AdA / n0) Formula (III)

[0115] In formula (III):

[0116] n0 is the initial mass of the added biobased sodium muconate, in g;

[0117] n AdA is the mass of the product sodium adipate after the reaction is completed, in g.

[0118] Example 1:

[0119] (1) Carrier pretreatment: the carrier is ultrasonically treated in a 0.5M aqueous Na2CO3 solution for 30min, and after solid-liquid separation, the carrier is dried to obtain a pretreated carrier powder;

[0120] (2) 10 g of alumina powder (pre-treated support powder) and 200 mL of water were added into a 250 mL flask and ultrasonically oscillated for 30 min to obtain a support suspension with a concentration of 50 g / L;

[0121] (3) Nickel nitrate and an appropriate amount of urea were dissolved in 50 mL of deionized water (mass ratio of nickel source to water was 0.05), and the molar ratio of urea to nickel source was 4 to obtain a nickel source-urea mixed solution.

[0122] (4) The support suspension and the nickel source-urea mixed solution were mixed and added to a jacketed beaker, which was sealed and stirred at 90°C water bath for 4 h. After the end of the reaction, the catalyst was dried at 90°C water bath to obtain a dried nickel-based hydrogenation catalyst precursor;

[0123] (5) The dried nickel-based hydrogenation catalyst precursor was placed in a tube furnace and hydrogen was introduced for high-temperature reduction at 300°C for 4 hours. The obtained nickel-based hydrogenation catalyst was stored in vacuum.

[0124] (6) The prepared nickel-based hydrogenation catalyst was pressed into a tablet and sieved, and then filled into a steel pipe with a diameter of 1 / 4 inch (inner diameter 0.635 cm). Inert glass beads were filled at both ends of the steel pipe to prevent the catalyst from leaking out. Hydrogen and the prepared bio-based sodium muconate solution (200 g / L) were introduced into the reactor. A laminar pump was used to control the liquid flow rate, and the flow rate of the introduced bio-based sodium muconate solution was 0.1 mL / min. A gas flow meter was used to control the gas flow rate, and the flow rate was 10 mL / min. The hydrogen pressure in the reactor was 3 MPa. The microreactor needed to be kept at a reaction temperature by water / oil bath, and the reaction was carried out at 80°C. The inner diameter of the reactor was 1 / 4 inch, and the height of the catalyst bed was 10 cm (residence time 157 s). The reaction was carried out for 157 s.

[0125] (7) The liquid product was analyzed using a Rezex-ROA organic acid H + The liquid product was analyzed using a Rezex-ROA organic acid H

[0126] According to the tests and calculations according to formula (I), (II) and (III), the conversion rate of bio-based sodium muconate was 100%, the selectivity of adipic acid was 99.2%, and the yield of adipic acid reached 99.2%.

[0127] Example 2:

[0128] The difference between this example and Example 1 is:

[0129] The reaction was carried out in a tank reactor, hydrogen pressure was 1 MPa, substrate concentration was 10 g / L, reaction time was 6 h, magnetic stirring was 600 r / min, and the reaction was carried out at 60°C.

[0130] The remaining reaction conditions were the same as in Example 1.

[0131] According to the test and calculation according to formula (I), (II) and (III), the conversion rate of bio-based sodium sticky furfuryl acid was 70.6%, the selectivity of adipic acid was 86.5%, and the yield of adipic acid reached 61.1%.

[0132] Example 3:

[0133] The difference between this example and Example 1 is:

[0134] The reaction was carried out in a tank reactor, hydrogen pressure was 1 MPa, substrate concentration was 10 g / L, reaction time was 6 h, magnetic stirring was 600 r / min, and the reaction was carried out at 70°C.

[0135] The remaining reaction conditions were the same as in Example 1.

[0136] According to the test and calculation according to formula (I), (II) and (III), the conversion rate of bio-based sodium sticky furfuryl acid was 89.9%, the selectivity of adipic acid was 82.3%, and the yield of adipic acid reached 74.0%.

[0137] Example 4:

[0138] The difference between this example and Example 1 is:

[0139] The reaction was carried out in a tank reactor, hydrogen pressure was 1 MPa, substrate concentration was 10 g / L, reaction time was 6 h, magnetic stirring was 600 r / min, and the reaction was carried out at 80°C.

[0140] The remaining reaction conditions were the same as in Example 1.

[0141] According to the test and calculation according to formula (I), (II) and (III), the conversion rate of bio-based sodium sticky furfuryl acid was 100%, the selectivity of adipic acid was 96.3%, and the yield of adipic acid reached 96.3%.

[0142] Example 5:

[0143] The difference between this example and Example 1 is:

[0144] The reaction was carried out in a tank reactor, hydrogen pressure was 1 MPa, substrate concentration was 10 g / L, reaction time was 6 h, magnetic stirring was 600 r / min, and the reaction was carried out at 90°C.

[0145] The remaining reaction conditions were the same as in Example 1.

[0146] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 99.0%, and the yield of adipic acid reaches 99.0%.

[0147] Example 6:

[0148] The difference between this example and Example 1 is that:

[0149] The reaction was carried out in a tank reactor, the hydrogen pressure was 1 MPa, the substrate concentration was 10 g / L, the reaction time was 6 h, the magnetic stirring speed was 600 rpm, and the reaction was carried out at 100 ℃.

[0150] The rest of the reaction conditions are the same as Example 1.

[0151] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 99.6%, and the yield of adipic acid reaches 99.6%.

[0152] Comparing the reaction conditions of Examples 2-6 with Example 1, the results are shown in Table 1 below

[0153] Table 1 Comparison of conditions of Examples 2-6 with Example 1

[0154] Example 7:

[0155] The difference between this example and Example 1 is that:

[0156] The reaction was carried out in a tank reactor, the reaction time was 18 h, the magnetic stirring speed was 600 rpm, and the reaction was carried out at 80 ℃.

[0157] The rest of the reaction conditions are the same as Example 1.

[0158] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 99.8%, and the yield of adipic acid reaches 99.8%.

[0159] Example 8:

[0160] The difference between this example and Example 1 is that:

[0161] The reaction was carried out in a tank reactor, the reaction time was 12 h, the magnetic stirring speed was 600 rpm, and the reaction was carried out at 80 ℃.

[0162] The rest of the reaction conditions are the same as Example 1.

[0163] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 89.8%, and the yield of adipic acid reaches 89.8%.

[0164] Example 9:

[0165] The difference between this example and Example 1 is that:

[0166] The reaction was carried out in a tank reactor, the reaction time was 6h, the magnetic stirring speed was 600r / min, and the reaction was carried out at 80℃.

[0167] The rest of the reaction conditions are the same as Example 1.

[0168] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 64.8%, the selectivity of adipic acid is 74.2%, and the yield of adipic acid reaches 48.1%.

[0169] Example 10:

[0170] The difference between this example and Example 1 is that:

[0171] The reaction was carried out in a tank reactor, the reaction time was 3h, the magnetic stirring speed was 600r / min, and the reaction was carried out at 80℃.

[0172] The rest of the reaction conditions are the same as Example 1.

[0173] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 32.6%, the selectivity of adipic acid is 47.5%, and the yield of adipic acid reaches 15.5%.

[0174] Comparing the reaction conditions of Examples 7-10 with Example 1, the results are shown in Table 2 below.

[0175] Table 2 Comparison of conditions of Examples 7-10 with Example 1 (substrate concentration is 200g / L)

[0176] Example 11:

[0177] The difference between this example and Example 1 is that:

[0178] 5g of SBA-15 molecular sieve was added in step (2). The substrate concentration was 10g / L and the hydrogen pressure was 1MPa in step (3).

[0179] The rest of the reaction conditions are the same as Example 1.

[0180] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 98.6%, and the yield of adipic acid reaches 98.6%.

[0181] Example 12:

[0182] The difference between this example and Example 1 is that:

[0183] 5 g of alumina beads were added in step (2). The substrate concentration was 10 g / L and the hydrogen pressure was 1 MPa in step (4).

[0184] The rest of the reaction conditions were the same as in Example 1.

[0185] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion of the biobased sodium muconate was 100%, the selectivity of adipic acid was 98.4%, and the yield of adipic acid reached 98.4%.

[0186] The reaction conditions of Examples 11-12 were compared with those of Example 1, and the results are shown in Table 3 below.

[0187] Table 3 Comparison of conditions of Examples 11-12 with Example 1

[0188] Example 13:

[0189] The difference between this example and Example 1 is that:

[0190] 5 g of alumina beads were added in step (2). The reaction temperature was 70°C, the substrate concentration was 10 g / L and the hydrogen pressure was 1 MPa in step (4).

[0191] The rest of the reaction conditions were the same as in Example 1.

[0192] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion of the biobased sodium muconate was 90.2%, the selectivity of adipic acid was 84.6%, and the yield of adipic acid reached 76.3%.

[0193] Example 14:

[0194] The difference between this example and Example 1 is that:

[0195] 5 g of alumina beads were added in step (2). The reaction temperature was 80°C, the substrate concentration was 10 g / L and the hydrogen pressure was 1 MPa in step (4).

[0196] The rest of the reaction conditions were the same as in Example 1.

[0197] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion of the biobased sodium muconate was 100%, the selectivity of adipic acid was 94.6%, and the yield of adipic acid reached 94.6%.

[0198] Example 15:

[0199] The difference between this example and Example 1 is that:

[0200] In step (2), 5 g of alumina beads was added. The reaction temperature was 90 °C, the substrate concentration in step (4) was 10 g / L, and the hydrogen pressure was 1 MPa.

[0201] The remaining reaction conditions were the same as in Example 1.

[0202] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion rate of bio-based sodium muconate was 100%, the selectivity of adipic acid was 98.6%, and the yield of adipic acid reached 98.6%.

[0203] Example 16:

[0204] The difference between this example and Example 1 is that:

[0205] In step (2), 5 g of alumina beads was added. The reaction temperature was 100 °C, the substrate concentration in step (4) was 10 g / L, and the hydrogen pressure was 1 MPa.

[0206] The remaining reaction conditions were the same as in Example 1.

[0207] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion rate of bio-based sodium muconate was 100%, the selectivity of adipic acid was 99.4%, and the yield of adipic acid reached 99.4%.

[0208] Comparing the reaction conditions of Examples 13-16 with Example 1, the results are shown in Table 4 below.

[0209] Table 4 Comparison of conditions of Examples 13-16 with Example 1

[0210] Example 17:

[0211] The difference between this example and Example 1 is that:

[0212] In step (4), 0.5 MPa of hydrogen was added, and the reaction temperature was 80 °C. The substrate concentration was 10 g / L.

[0213] The remaining reaction conditions were the same as in Example 1.

[0214] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion rate of bio-based sodium muconate was 100%, the selectivity of adipic acid was 74.2%, and the yield of adipic acid reached 74.2%.

[0215] Example 18:

[0216] The difference between this example and Example 1 is that:

[0217] Step (4) was carried out at 80°C with 1.5 MPa hydrogen gas. The substrate concentration was 10 g / L

[0218] The rest of the reaction conditions were the same as in Example 1.

[0219] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion rate of the bio-based sodium muconate was 100%, the selectivity of adipic acid was 99.4%, and the yield of adipic acid reached 99.4%.

[0220] Example 19:

[0221] The difference between this example and Example 1 is that:

[0222] Step (4) was carried out at 80°C with 2 MPa hydrogen gas. The substrate concentration was 10 g / L

[0223] The rest of the reaction conditions were the same as in Example 1.

[0224] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion rate of the bio-based sodium muconate was 100%, the selectivity of adipic acid was 99.5%, and the yield of adipic acid reached 99.5%.

[0225] Example 20:

[0226] The difference between this example and Example 1 is that:

[0227] Step (4) was carried out at 80°C with 3 MPa hydrogen gas. The substrate concentration was 10 g / L

[0228] The rest of the reaction conditions were the same as in Example 1.

[0229] According to the tests and calculations according to Formulas (I), (II) and (III), the conversion rate of the bio-based sodium muconate was 100%, the selectivity of adipic acid was 100%, and the yield of adipic acid reached 100%.

[0230] Comparisons of the reaction conditions of Examples 17-20 and Example 1 are shown in Table 5 below.

[0231] Table 5 Comparison of the conditions of Examples 17-20 and Example 1

[0232] Example 21:

[0233] The difference between this example and Example 1 is that:

[0234] Step (4) was carried out at 80°C with 30 g / L of a bio-based sodium muconate solution for 1 min.

[0235] 1 MPa hydrogen gas was added

[0236] The rest of the reaction conditions are the same as in Example 1.

[0237] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 98.6%, and the yield of adipic acid reaches 98.6%.

[0238] Example 22:

[0239] The difference between this example and Example 1 is that:

[0240] In step (4), 50 g / L of bio-based sodium muconate solution is added, and the reaction is carried out for 1 min at a reaction temperature of 80°C.

[0241] 1 MPa of hydrogen is added

[0242] The rest of the reaction conditions are the same as in Example 1.

[0243] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 98.4%, and the yield of adipic acid reaches 98.4%.

[0244] Example 23:

[0245] The difference between this example and Example 1 is that:

[0246] In step (4), 70 g / L of bio-based sodium muconate solution is added, and the reaction is carried out for 1 min at a reaction temperature of 80°C.

[0247] 1 MPa of hydrogen is added

[0248] The rest of the reaction conditions are the same as in Example 1.

[0249] According to the test and calculation of formula (I), (II) and (III), the conversion rate of bio-based sodium muconate is 100%, the selectivity of adipic acid is 99.4%, and the yield of adipic acid reaches 99.4%.

[0250] Example 24:

[0251] The difference between this example and Example 1 is that:

[0252] In step (4), 100 g / L of bio-based sodium muconate solution is added, and the reaction is carried out for 80 s at a reaction temperature of 80°C. 1.5 MPa of hydrogen is added. The hydrogen pressure is 1.5 MPa

[0253] The rest of the reaction conditions are the same as in Example 1.

[0254] Based on tests and calculations using formulas (I), (II), and (III), the conversion rate of bio-based sodium kanamylate was 100%, the selectivity of adipic acid was 99.6%, and the yield of adipic acid reached 99.6%.

[0255] The reaction conditions of Examples 21-24 were compared with those of Example 1, and the results are shown in Table 6 below.

[0256] Table 6 Comparison of conditions between Examples 21-24 and Example 1

[0257] Example 25:

[0258] The difference between this embodiment and embodiment 1 is that:

[0259] Nickel-based catalysts prepared using the conventional impregnation method

[0260] The remaining reaction conditions were the same as in Example 1.

[0261] Based on tests and calculations using formulas (I), (II), and (III), the conversion rate of bio-based sodium kanamylate was 54.1%, the selectivity for adipic acid was 42.6%, and the yield of adipic acid reached 23.1%.

[0262] The reaction conditions of Example 25 were compared with those of Example 1, and the results are shown in Table 7 below.

[0263] Table 7 Comparison of conditions between Example 25 and Example 1

[0264] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on 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 terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A nickel-based hydrogenation catalyst for the production of bio-based adipic acid, consisting of a support loaded with metallic nickel, wherein, The average particle size of the metal nickel is 2.5-4.5 nm, the specific surface area of the nickel-based hydrogenation catalyst is 50-300 m 2 / g; the loading of the metal nickel in the nickel-based hydrogenation catalyst is 2-40 wt%.

2. A preparation method of a nickel-based hydrogenation catalyst, comprising carrier pretreatment and loading of metal nickel by a precipitation-deposition method, which comprises: Step A: ultrasonic pretreatment of the carrier in a Na2CO3 aqueous solution, solid-liquid separation, and drying to obtain a pretreated carrier; Step B: ultrasonic treatment of the pretreated carrier in water to obtain a carrier suspension; Step C: mixing of a nickel source with urea and water to obtain a nickel source-urea mixture; Step D: mixing of the carrier suspension with the nickel source-urea mixture, sealed stirring impregnation, then opening the seal, stirring and drying until the water is completely volatilized to obtain a dried nickel-based hydrogenation catalyst precursor; Step E: high-temperature reduction of the dried nickel-based hydrogenation catalyst precursor in a hydrogen atmosphere to obtain a nickel-based hydrogenation catalyst.

3. The preparation method according to claim 2, wherein in Step A, the concentration of the Na2CO3 aqueous solution is 0.1-0.8 M, and the mass ratio of the Na2CO3 aqueous solution to the carrier is 5-15:1; in Step C, the molar ratio of the urea to the nickel source is 2-8; in Step C, the mass ratio of the nickel source to water is 0.01-0.1; in Step D, the mass ratio of the pretreated carrier to the nickel source is 0.65-10; and the concentration of the carrier suspension is 20-100 g / L.

4. The preparation method according to claim 2 or 3, wherein in Steps A and B, the ultrasonic treatment time is 0-60 min; in Step D, the impregnation temperature is 30-100℃, and the impregnation time is 2-6 h; in Step D, the temperature for evaporation drying is 30-100℃; and in Step E, the high-temperature reduction temperature is 300-1000℃, and the high-temperature reduction time is 60-300 min.

5. A hydrogenation reaction system for preparing bio-based adipic acid, comprising a batch stirring reaction kettle or a microreaction device.

6. The hydrogenation reaction system according to claim 5, wherein the microreaction device comprises, in sequence, a reaction liquid storage tank, a laminar flow pump, a micro-mixer, a micro-packed bed reactor, a phase separator, and a product collector, a hydrogen source is connected to the micro-mixer, a gas flow meter is arranged between the hydrogen source and the micro-mixer, and a back pressure valve is arranged on the phase separator; the micro-packed bed reactor has an inner diameter of 0.5-10 mm; and the micro-packed bed reactor has a length of 2-20 cm.

7. A preparation method of bio-based adipic acid, which comprises subjecting bio-based muconic acid or bio-based sodium muconate to a hydrogenation reaction in the hydrogenation reaction system according to claim 5 or 6 in the presence of the nickel-based hydrogenation catalyst according to claim 1 or prepared by the preparation method according to any one of claims 2-4 to obtain adipic acid. When the hydrogenation reaction system comprises a batch stirring reaction kettle, the preparation method of bio-based adipic acid comprises placing the nickel-based hydrogenation catalyst into the batch stirring reaction kettle, adding an aqueous bio-based muconic acid solution or an aqueous sodium muconate solution, and charging hydrogen to perform a hydrogenation reaction to obtain adipic acid.

9. The preparation method according to claim 8, wherein ​ ​ ​ ​ ​ ​ ​ 8. The preparation method according to claim 7, characterized in that, ​ ​ The concentration of the aqueous solution of bio-based muconic acid or sodium muconate is ≥10 g / L; The mass ratio of bio-based muconic acid or sodium muconate to the nickel-based hydrogenation catalyst is 1-50; The pressure of hydrogen in the batch stirred reactor is 0.1-5 MPa; The temperature of the hydrogenation reaction is 50-200℃; The time of the hydrogenation reaction is 5 min-24 h.

10. The preparation method according to claim 7, characterized in that, When the hydrogenation reaction system comprises a micro-reactor device, the nickel-based hydrogenation catalyst is filled into a micro-packed bed reactor, the aqueous solution of muconic acid or the aqueous solution of sodium muconate and hydrogen are introduced into the micro-packed bed reactor, the micro-packed bed reactor is heated by water bath or oil bath, and catalytic hydrogenation reaction is carried out to obtain adipic acid.

11. The preparation method according to claim 10, characterized in that, The filling of the nickel-based hydrogenation catalyst into the micro-packed bed reactor comprises: first, tabletting the powder-shaped nickel-based hydrogenation catalyst prepared by using a powder-shaped carrier, sieving, and then filling into the micro-packed bed reactor, or directly filling the spherical hydrogenation catalyst prepared by using a spherical carrier into the micro-packed bed reactor; The height of the filled catalyst bed layer is 2-15 cm; both ends of the filled catalyst bed layer are filled with inert glass beads; The molar concentration of the aqueous solution of bio-based muconic acid or sodium muconate is ≥10 g / L; The flow rate of the aqueous solution of bio-based muconic acid or sodium muconate introduced is 0.1-2 mL / min; The pressure of hydrogen introduced into the micro-packed bed reactor is 0.16-10.0 MPa; the flow rate of hydrogen introduced is 10-100 mL / min; The temperature of the hydrogenation reaction is 30-200℃; The time of the hydrogenation reaction is 10 s-10 min.

12. The preparation method according to any one of claims 7-11, The preparation method comprises: after the hydrogenation reaction of the aqueous solution of muconic acid, an aqueous solution of adipic acid is obtained, and then adipic acid solid is precipitated by cooling; Or, after the hydrogenation reaction of the aqueous solution of sodium muconate, an aqueous solution of sodium adipate is obtained, and then the adipic acid solid is precipitated by cooling after acidification treatment by dropwise adding an inorganic acid.

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