Process for the preparation of 1,4-butenediol from 1,4-butynediol

Abstract

The present application relates to the field of catalytic hydrogenation, and discloses a method for preparing 1,4-butenediol from 1,4-butynediol, which comprises: contacting 1,4-butynediol and hydrogen in the presence of a catalytic composition for selective hydrogenation; wherein the catalytic composition comprises carbon-coated nickel nanocomposites and a catalytic additive; the carbon-coated nickel nanocomposites comprise a nickel nanoparticle core and a graphitized carbon layer shell wrapped around the surface of the nickel nanoparticle core, and the lattice structure of the nickel nanoparticle comprises a face-centered cubic lattice structure and / or a close-packed hexagonal lattice structure; and the catalytic additive is dicyanediamine and / or thiophene. The method uses carbon-coated nickel nanocomposites as catalysts, introduces dicyanediamine and / or thiophene as catalytic additives, and realizes high selectivity and safety in the synthesis process of 1,4-butenediol through the synergistic effect of carbon-coated nickel nanocomposites and catalytic additives.

Description

Technical Field

[0001] This invention relates to the field of catalytic hydrogenation, and more specifically to a method for preparing 1,4-butenediol from 1,4-butynediol. Background Technology

[0002] 1,4-Butenediol (BED) is an important chemical raw material with wide applications in the pharmaceutical, pesticide, and textile industries. In the pharmaceutical field, BED is a raw material for the synthesis of vitamin B6; in the pesticide field, BED can be used to prepare organochlorine insecticides (endosulfan); in the textile and resin industries, BED can be used to synthesize fine chemical raw materials such as maleic acid and polyurethane, and can also be used as a plasticizer, crosslinking agent, and bactericide for alkyd resins. Currently, industrially, 1,4-butenediol is mainly produced through the selective hydrogenation of 1,4-butynediol.

[0003] In existing technologies, the catalysts used in the hydrogenation process of 1,4-butynediol are mainly noble metal Pd-based or non-noble metal Ni-based catalysts. For noble metal Pd-based catalysts, toxic promoters such as Pb are usually added to obtain high BED selectivity, which is environmentally unfriendly and has high catalyst costs. Commonly used Ni-based catalysts, such as Raney-Ni, are prone to spontaneous combustion in air when dry, so strict operating procedures are required during the production, use, and recycling of the catalyst to avoid safety accidents. In addition, Raney-Ni catalysts also face the problem of low hydrogenation selectivity. For example, Chen et al. (Catal Lett (2014) 144:1118–1126) applied the Raney Ni-Si catalyst to the selective hydrogenation of 1,4-butynediol to 1,4-butenediol. Among them, the Raney Ni catalyst achieved a 1,4-butynediol conversion of 96.7%, but the selectivity of the target product 1,4-butenediol was only 67.3%.

[0004] Therefore, the development of a simple, efficient, and environmentally friendly catalyst for the selective hydrogenation of 1,4-butynediol with good catalytic hydrogenation performance, stability, and safety is of great significance for the synthesis of 1,4-butynediol and its downstream applications. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of poor hydrogenation selectivity, poor reaction stability, and high cost in the selective hydrogenation reaction of 1,4-butynediol in the prior art, and to provide a method for preparing 1,4-butenediol from 1,4-butynediol. This method does not require a precious metal catalyst, has low reaction cost, is environmentally friendly, and has good selectivity for 1,4-butenediol.

[0006] To achieve the above objectives, the present invention provides a method for preparing 1,4-butenediol from 1,4-butynediol, the method comprising: selectively hydrogenating 1,4-butynediol by contacting it with hydrogen in the presence of a catalytic composition;

[0007] The catalytic composition includes a carbon-coated nickel nanocomposite material and a catalytic additive; the carbon-coated nickel nanocomposite material includes a nickel nanoparticle core and a graphitized carbon layer shell covering the surface of the nickel nanoparticle core, and the crystal structure of the nickel nanoparticle core includes a face-centered cubic lattice structure and / or a close-packed hexagonal lattice structure.

[0008] The catalytic additive is dicyandiamine and / or thiophene.

[0009] The present invention provides a method for preparing 1,4-butenediol from 1,4-butynediol, using a carbon-coated nickel nanocomposite material as a catalyst for the hydrogenation reduction of 1,4-butynediol. Because the catalyst material contains a graphitized carbon layer / metal core-shell structure, the nickel core is highly stable, non-flammable, and has low hazard, making it suitable for storage and transportation, thus ensuring the safety of the composite material. Furthermore, by introducing dicyandiamine and / or thiophene as catalytic additives, the synergistic effect of the carbon-coated nickel nanocomposite material and the catalytic additives achieves high selectivity and safety in the 1,4-butenediol synthesis process.

[0010] Meanwhile, due to the strong magnetic properties of carbon-coated nickel nanocomposites, they can also be conveniently used for magnetic separation of catalysts or for processes such as magnetically stabilized beds. Attached Figure Description

[0011] Figure 1 This is the X-ray diffraction pattern of the carbon-coated nickel nanocomposite material prepared in Example 1;

[0012] Figure 2 This is a transmission electron microscope image of the carbon-coated nickel nanocomposite material prepared in Example 1;

[0013] Figure 3 This is the Ni 2p X-ray photoelectron spectrum of the carbon-coated nickel nanocomposite material prepared in Example 1;

[0014] Figure 4 The image shows the XRD pattern of the carbon-coated nickel nanocomposite material prepared in Example 2.

[0015] Figure 5A This is the N2 adsorption-desorption isotherm curve of the carbon-coated nickel nanocomposite material prepared in Example 2;

[0016] Figure 5B This is a pore size distribution curve of the carbon-coated nickel nanocomposite material prepared in Example 2. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] In this invention, the term "oxygen doping" refers to the element oxygen. The "oxygen content" of the nickel carbide nanocomposite material refers to the content of the element oxygen, specifically the oxygen element present in various forms in the carbon matrix formed during the preparation of the carbon-coated nickel nanocomposite material. The "oxygen content" is the total content of all forms of oxygen element.

[0019] In this invention, the term "graphitized carbon layer" refers to a carbon structure whose layered structure can be clearly observed under a high-resolution transmission electron microscope, rather than an amorphous structure.

[0020] In this invention, the term "core-shell structure" refers to a core consisting of metal nanoparticles and a shell consisting of an oxygen-doped or nitrogen- and oxygen-doped graphitized carbon layer.

[0021] This invention provides a method for preparing 1,4-butenediol from 1,4-butynediol, the method comprising: selectively hydrogenating 1,4-butynediol by contacting it with hydrogen in the presence of a catalytic composition;

[0022] The catalytic composition includes a carbon-coated nickel nanocomposite material and a catalytic additive; the carbon-coated nickel nanocomposite material includes a nickel nanoparticle core and a graphitized carbon layer shell covering the surface of the nickel nanoparticle core, and the lattice structure of the nickel nanoparticles includes a face-centered cubic lattice structure and / or a close-packed hexagonal lattice structure.

[0023] The catalytic additive is dicyandiamine and / or thiophene.

[0024] Existing technologies use Raney Ni catalysts to catalyze the conversion of 1,4-butynediol, but their selectivity is poor. The inventors of this invention discovered that carbon-coated nickel nanocomposite materials, acting synergistically with dicyandiamine and / or thiophene additives, form a catalytic composition for the hydrogenation reduction of 1,4-butynediol, achieving high selectivity in the synthesis of 1,4-butenediol. Because the carbon-coated nickel nanocomposite material contains a graphitized carbon layer / metal core-shell structure, the nickel material in the core is highly stable, ensuring the safety of the composite material. In existing Ni-based catalysts, whether supported Ni catalysts, Raney nickel, or amorphous nickel catalysts, the nickel is exposed. When dicyandiamine or thiophene, containing N and S small organic molecules, are present in the solution, they often undergo strong adsorption on the Ni surface, leading to catalyst deactivation or partial deactivation. In this invention, due to the presence of a graphitized carbon layer, the nickel core is coated, which to some extent reduces the deactivation caused by strong adsorption of additives, while also unexpectedly improving catalytic selectivity.

[0025] In this invention, the carbon-coated nickel nanocomposite material can be any carbon-coated nickel nanocomposite material known in the art, and this invention does not impose any particular limitation on it. This invention also does not impose any particular limitation on the preparation method of the carbon-coated nickel nanocomposite material; any method known in the art can be used to prepare it. For example, the carbon-coated nickel nanocomposite material comprising a nickel nanoparticle core and a graphitized carbon layer shell coating the surface of the nickel nanoparticle core can be prepared according to the methods disclosed in CN109309213A, CN109304475A, CN109304476A, and CN109304194A, wherein the lattice structure of the nickel nanoparticles comprises a face-centered cubic lattice structure and / or a close-packed hexagonal lattice structure.

[0026] According to the present invention, preferably, the mass ratio of carbon-coated nickel nanocomposite material to catalytic additive in the catalytic composition is 1:0.02-1, more preferably 1:0.05-0.5. In the above preferred embodiment, it is beneficial to further leverage the synergistic effect of the carbon-coated nickel nanocomposite material and the catalytic additive, thereby improving the selectivity of 1,4-butenediol.

[0027] In this invention, the carbon-coated nickel nanocomposite material and the catalytic additive can be first prepared into a catalytic composition and then used for the reaction, or the two can be directly added together to the reactor for the reaction.

[0028] There are no particular limitations on the preparation method of the catalytic composition. Preferably, the preparation method of the catalytic composition includes mixing carbon-coated nickel nanocomposite material and catalytic additive. The mixing can be carried out using any conventional mixing process in the art, as long as it can achieve uniform mixing of carbon-coated nickel nanocomposite material and catalytic additive. The present invention does not have any special requirements in this regard.

[0029] According to the present invention, preferably, the average particle size of the carbon-coated nickel nanocomposite material is 1-200 nm, more preferably 3-100 nm, and even more preferably 4-50 nm.

[0030] The average particle size of the carbon-coated nickel composite was measured using TEM images. The particle size of the core nickel particles was calculated from the XRD pattern using the Scherrer formula: D = kγ / (Bcosθ). Here, k is the Scherrer constant (k = 0.89), B is the full width at half maximum (FWHM), θ is the diffraction angle in radians, and γ is the X-ray wavelength (0.154054 nm).

[0031] According to the present invention, preferably, the carbon-coated nickel nanocomposite material has at least one mesopore distribution peak, and more preferably, more than one mesopore distribution peak. More preferably, the carbon-coated nickel nanocomposite material has two distribution peaks with mesopore sizes of 2-5 nm and 8-12 nm; using a carbon-coated nickel nanocomposite material with the above-mentioned preferred pore structure is beneficial to improving mass transfer efficiency. Preferably, in the carbon-coated nickel nanocomposite material, the proportion of mesopore volume to the total pore volume is greater than 50%, and more preferably greater than 80%.

[0032] The term "mesopore" is defined as a pore with a diameter in the range of 2-50 nm. Pores with a diameter less than 2 nm are defined as micropores, and pores with a diameter greater than 50 nm are defined as macropores.

[0033] The term "mesopore distribution peak" refers to the mesopore distribution peak on the pore distribution curve obtained by calculating the desorption curve according to the Barrett-Joyner-Halenda (BJH) method.

[0034] The term "acid pickling loss rate" refers to the proportion of nickel lost after acid pickling of carbon-coated nickel nanocomposites. It reflects the tightness of the coating of nickel nanoparticles by the graphitized carbon layer. If the coating of nickel nanoparticles by the graphitized carbon layer is not tight, the nickel in the core will be dissolved and lost by acid after pickling. A higher acid pickling loss rate indicates a lower tightness of coating of nickel nanoparticles by the graphitized carbon layer; conversely, a lower acid pickling loss rate indicates a higher tightness of coating of nickel nanoparticles by the graphitized carbon layer. The "acid pickling loss rate" is measured and calculated as follows:

[0035] Add 1 g of sample to 20 mL of sulfuric acid aqueous solution (1 mol / L), treat the sample at 90 °C for 8 h, then wash with deionized water until neutral, dry, weigh, and analyze, and calculate the acid washing loss rate according to the following formula.

[0036] Pickling loss rate = [1 - (mass fraction of nickel in the pickled composite material × mass of the pickled composite material) ÷ ​​(mass fraction of nickel in the composite material to be pickled × mass of the composite material to be pickled)] × 100%.

[0037] In this invention, preferably, the acid pickling loss rate of the carbon-coated nickel nanocomposite material is ≤40%, more preferably ≤30%, and more preferably ≤10%.

[0038] In this invention, preferably, based on the total amount of carbon-coated nickel nanocomposite material, the content of Ni is 20-85%, the content of C is 14-79%, the content of O is 0.5-6%, the content of N is 0-6%, and the content of H is 0.1-2.5%.

[0039] To further improve the selective hydrogenation performance of the catalytic composition for 1,4-butynediol, preferably, the preparation method of the carbon-coated nickel nanocomposite material includes:

[0040] S1, a nickel source, a polycarboxylic acid and a first solvent are mixed to form a homogeneous solution, and then the first solvent in the homogeneous solution is removed to obtain a precursor;

[0041] S2, the precursor is subjected to high-temperature pyrolysis under an inert protective atmosphere and / or a reducing atmosphere.

[0042] In existing technologies, it is difficult to fabricate nanoscale core-shell structures with tightly coated graphitized carbon layers and transition metal cores, especially to simultaneously fabricate such tightly coated core-shell structures and abundant mesoporous structures in composite materials. This invention not only achieves these objectives but also further fabricates tightly coated core-shell structures while simultaneously creating abundant hierarchical mesoporous structures in composite materials.

[0043] According to the present invention, preferably, the nickel source is at least one of an organic acid salt, a carbonate, and a basic carbonate of nickel; more preferably, it is an organic carboxylate of nickel, and more preferably, it is nickel acetate.

[0044] This invention does not impose any particular limitation on the polybasic organic carboxylic acid; it can be a nitrogen-containing or nitrogen-free polybasic organic carboxylic acid, as long as it can be mixed with the nickel source in the first solvent to form a homogeneous solution. The polybasic organic carboxylic acid can be, but is not limited to, one or more of citric acid, maleic acid, trimesic acid, terephthalic acid, malic acid, iminodiacetic acid, diethylenetriaminepentaacetic acid, 1,3-propanediaminetetraacetic acid, ethylenediaminetetraacetic acid, and pyridinedicarboxylic acid. The pyridinedicarboxylic acid can be 2,3-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 3,4-pyridinedicarboxylic acid, or 3,5-pyridinedicarboxylic acid. Most preferably, the polybasic organic carboxylic acid is citric acid.

[0045] In this invention, preferably, the molar ratio of the nickel source (calculated as nickel element) to the polycarboxylic acid (calculated as carboxylate group) is 1:2-10, more preferably 1:2-5, and even more preferably 1:2-4.

[0046] In this invention, there are no particular limitations on the method of forming the homogeneous solution. It can be formed by heating, preferably by heating and stirring. There are also no particular limitations on the heating temperature and the stirring rate, as long as the method enables the formation of the homogeneous solution.

[0047] In this invention, the selection range for the first solvent is relatively wide. The first solvent can be selected from at least one of water, methanol, ethanol, n-propanol, and isopropanol, preferably water and / or ethanol, and more preferably water. There is no particular limitation on the amount of the first solvent used; it is simply sufficient to form the homogeneous solution.

[0048] In this invention, the first solvent in the homogeneous solution can be removed by direct evaporation. The evaporation temperature and process can be based on existing technologies known to those skilled in the art. For example, the first solvent in the homogeneous solution can be removed by heating and evaporating to dryness.

[0049] According to the present invention, preferably, in step S2, the high-temperature pyrolysis includes: heating the precursor to the temperature of the high-temperature pyrolysis under an inert protective atmosphere and / or a reducing atmosphere, and maintaining the temperature at a constant temperature.

[0050] Preferably, the heating rate is 1-20℃ / min, more preferably 2-10℃ / min; the constant temperature is 400-800℃, more preferably 450-700℃; and the constant temperature time is 1-360min, more preferably 10-180min.

[0051] In this invention, the high-temperature pyrolysis can be carried out in an inert atmosphere, a reducing atmosphere, or a mixture of an inert atmosphere and a reducing atmosphere.

[0052] Preferably, the inert atmosphere is provided by at least one of nitrogen, argon, neon and helium.

[0053] Preferably, the reducing atmosphere is hydrogen.

[0054] In this invention, preferably, the preparation method of the carbon-coated nickel nanocomposite material further includes: contacting the product of the high-temperature pyrolysis with an acidic solution to remove the incompletely coated Ni core.

[0055] In this invention, the acidic solution can be any conventional non-oxidizing strong acid aqueous solution in the art, preferably, the acidic solution is selected from at least one aqueous solution of hydrochloric acid, sulfuric acid and hydrofluoric acid.

[0056] Preferably, the concentration of the acidic solution is 0.1-3 mol / L.

[0057] The carbon-coated nickel nanocomposite material prepared by the above method achieves 100% atomic utilization of the nickel source. While achieving better coating effects, it overcomes the drawbacks of existing technologies for preparing metal-organic framework precursors, such as the need for high-temperature, high-pressure reactors for self-assembly, significant waste of organic solvents, and cumbersome purification steps. Furthermore, it eliminates the need for polymeric auxiliaries, simplifying the reaction steps. Moreover, in the carbon-coated nickel nanocomposite material prepared by the method of this invention, the nickel nanoparticles are more tightly coated by the graphitized carbon layer, enabling its use under more demanding conditions. It is particularly suitable for the reaction of 1,4-butynediol to 1,4-butenediol, which is beneficial for improving the stability of the catalytic composition.

[0058] In this invention, preferably, the method comprises selectively hydrogenating 1,4-butynediol and hydrogen by contacting them in the presence of a catalytic composition and a second solvent.

[0059] The present invention does not have a special limitation on the order of adding the reactants. The carbon-coated nickel nanocomposite material, the catalytic additive, 1,4-butynediol and the second solvent can be added to the reaction vessel together for mixing. Alternatively, the carbon-coated nickel nanocomposite material and the catalytic additive can be mixed first to obtain a catalytic composition, and then the catalytic composition, 1,4-butynediol and the second solvent can be added to the reaction vessel together for mixing.

[0060] In this invention, the range of choices for the second solvent is relatively wide. Preferably, the second solvent is selected from at least one of water, alcohols, ethers and alkanes.

[0061] Preferably, the amount of the second solvent is such that the concentration of 1,4-butynediol is 5-600 g / L, more preferably 10-500 g / L. The solubility refers to the concentration of 1,4-butynediol in the second solvent.

[0062] According to the present invention, preferably, the amount of the catalytic composition and 1,4-butynediol is such that the mass ratio of carbon-coated nickel nanocomposite material to 1,4-butynediol is 1:1-50, preferably 1:2-40.

[0063] According to the present invention, preferably, the conditions for selective hydrogenation include: a pressure of 0.5-4 MPa, more preferably 1-3 MPa; and a temperature of 15-200°C, more preferably 40-100°C. The pressure is the hydrogen partial pressure.

[0064] The present invention will be described in detail below through embodiments.

[0065] In the following examples and comparative examples:

[0066] The average particle size of the carbon-coated nickel composite was measured using TEM images. The average particle size of the nickel core particles was calculated from the XRD pattern using the Scherrer formula: D = kγ / (Bcosθ). Here, k is the Scherrer constant (k = 0.89), B is the full width at half maximum (FWHM), θ is the diffraction angle in radians, and γ is the X-ray wavelength (0.154054 nm).

[0067] The pore structure properties of the material were determined using the BET test method. Specifically, a Quantachrome AS-6B analyzer was used for measurement. The specific surface area of ​​the catalyst was obtained by the Brunauer-Emmett-Taller (BET) method, and the pore distribution curve was calculated from the desorption curve using the Barrett-Joyner-Halenda (BJH) method.

[0068] The elemental composition of the material surface was determined using X-ray photoelectron spectroscopy (XPS). The XPS used was a VG Scientific ESCALab220i-XL model equipped with Avantage V5.926 software. The XPS analysis conditions were as follows: monochromatic AlKα X-ray excitation source, power 330 W, and a base vacuum of 3 × 10⁻⁶. -9 mbar.

[0069] The surface morphology of the material was characterized by transmission electron microscopy (TEM). The TEM used was a JEM-2100 (Nippon Electron Ltd.), and the TEM testing conditions were: accelerating voltage of 200 kV.

[0070] Analysis of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) was performed on an Elementar Micro Cube elemental analyzer. The specific operating procedures and conditions were as follows: 1-2 mg of sample was weighed into a tin cup, placed in the autosampler tray, and introduced into the combustion tube through a ball valve for combustion at 1000℃ (helium purging was used to remove atmospheric interference during sample introduction). The combusted gas was then reduced with copper to form nitrogen, carbon dioxide, and water. The mixed gas was separated by three desorption columns and sequentially detected by a TCD detector. Oxygen analysis utilized high-temperature decomposition; under the action of a carbon catalyst, oxygen in the sample was converted to CO, which was then detected by a TCD detector.

[0071] The metal element content is the normalized result after deducting the carbon, hydrogen, oxygen, and nitrogen content of the material.

[0072] The conversion rate of the reactants and the selectivity of the target product are calculated using the following formulas:

[0073] Conversion rate (%) = (mass of reactants already reacted / mass of reactants added) × 100%.

[0074] The following preparation examples illustrate the preparation of carbon-coated nickel nanocomposites.

[0075] Preparation Example 1

[0076] S1. Weigh 21.01g of citric acid monohydrate and 14.55g of basic nickel carbonate (the molar ratio of basic nickel carbonate based on nickel element to citric acid monohydrate based on carboxylate ion is 1:3) and add them to 150mL of deionized water. Stir at 100℃ to obtain a homogeneous solution, and continue to heat to dryness. Grind the obtained solid to obtain the precursor.

[0077] S2. The obtained precursor is placed in a ceramic boat, and then the ceramic boat is placed in the constant temperature zone of a tube furnace. Nitrogen gas is introduced at a flow rate of 100 mL / min, and the temperature is increased to 600℃ at a rate of 10℃ / min. After holding at the temperature for 120 min, the heating is stopped, and the mixture is cooled to room temperature under a nitrogen atmosphere to obtain carbon-coated nickel nanocomposite material.

[0078] Figure 1 This is the X-ray diffraction pattern of the carbon-coated nickel nanocomposite material prepared in Example 1. Figure 1 The results show that it mainly exhibits diffraction peaks for fcc-Ni and hcp-Ni, as well as diffraction peaks for carbon materials. Using the Scherrer equation, the average particle size of the nickel core nanoparticles is calculated to be 11.7 nm.

[0079] Figure 2The image shows a TEM image of the carbon-coated nickel nanocomposite material prepared in Example 1. It can be seen from the image that the outer layer of the nickel nanoparticles is wrapped with several layers of graphitized carbon. The average particle size of the carbon-coated nickel nanoparticles is 13.5 nm, and the average particle size of the nickel core is about 12.5 nm, which is consistent with the calculation results based on the XRD spectrum. Figure 3 This is the Ni 2p X-ray photoelectron spectrum of the carbon-coated nickel nanocomposite material prepared in Example 1. The spectrum shows that nickel is in its elemental valence state, indicating that the carbon coating significantly improves the stability of the elemental nickel nanoparticles in air. Elemental analysis determined the nanomaterial's C content to be 22.49%, H content to be 0.55%, O content to be 1.46%, and the normalized Ni content to be 75.50%.

[0080] Preparation Example 2

[0081] S1. Weigh 4.38 g (15 mmol) of ethylenediaminetetraacetic acid and 1.85 g (20 mmol) of nickel hydroxide (the molar ratio of nickel hydroxide based on nickel element to ethylenediaminetetraacetic acid based on carboxyl group is 1:3) and add them to 150 mL of deionized water. Stir at 75 °C to obtain a homogeneous solution, and continue to heat to dryness. Grind the solid to obtain the precursor.

[0082] S2. Place the precursor obtained in step S1 into a ceramic boat, then place the ceramic boat in the constant temperature zone of a tube furnace, introduce nitrogen gas at a flow rate of 80 mL / min, and heat it to 600℃ at a rate of 3℃ / min. After holding the temperature for 3 hours, stop heating and cool it to room temperature under a nitrogen atmosphere.

[0083] S3. Add the product obtained in step S2 to 60 mL of 0.5 mol / L H2SO4 solution, stir and reflux at 80 °C for 6 h, filter the solution, wash with deionized water until neutral, and then dry the powder in an oven at 100 °C for 2 h to obtain carbon-coated nickel nanocomposite material.

[0084] The TEM images show that the nickel nanoparticles are coated with several layers of graphitized carbon, and the average particle size of the carbon-coated nickel nanocomposite is 12.6 nm.

[0085] Figure 4 This is the XRD pattern of the carbon-coated nickel nanocomposite material prepared in Example 2. Figure 4 The results show that only diffraction peaks of carbon materials, as well as diffraction peaks of hcp-Ni and fcc-Ni, are present. Using the Scherrer equation, the average particle size of the nickel nanoparticles is calculated to be 10.5 nm.

[0086] Figure 5A This is the N2 adsorption-desorption isotherm curve of the carbon-coated nickel nanocomposite material prepared in Example 2; Figure 5BThis is a pore size distribution curve of the carbon-coated nickel nanocomposite material prepared in Example 2. It shows that the pore size distribution of this material exhibits two peaks at diameters of 3.7 nm and 10.0 nm. The specific surface area of ​​this nanocomposite material is 224 m². 2 / g, pore volume is 0.457cm³ 3 / g, of which mesoporous volume accounts for 99.7% of the total pore volume. Elemental analysis determined the nanomaterial's C content to be 37.42%, H content to be 0.54%, N content to be 1.45%, O content to be 1.86%, and normalized Ni content to be 58.73%. Measured and calculated according to the methods described in the terminology section, the acid washing loss rate of the composite material obtained in this example before purification was 12%. Based on the methods described in the terminology section, further increasing the acid washing time did not significantly change the acid washing loss rate.

[0087] Comparative Preparation Example 1

[0088] The catalyst was prepared according to the method disclosed in the literature "MOF-derived Ni-based nanocomposites as robust catalysts for chemoselective hydrogenation of functionalized nitro compounds", specifically:

[0089] (1) 6.64 g of terephthalic acid was weighed and dissolved in 50 mL of N,N-dimethylformamide to obtain solution A; 3.46 g of nickel chloride hexahydrate was weighed and dissolved in 100 mL of N,N-dimethylformamide to obtain solution B; wherein the molar ratio of nickel chloride hexahydrate (calculated as nickel element) to terephthalic acid (calculated as carboxyl group) was 1:5.5; solution B was added dropwise to solution A under stirring conditions, and stirred at room temperature for 1 h. Then the mixed solution was transferred to a stainless steel reactor with a polytetrafluoroethylene liner and heated at 120 °C for 16 h. After cooling to room temperature, the precipitate was collected by centrifugation and washed twice with DMF and ethanol, respectively. The precipitate was then dried at 70 °C to obtain the Ni-MOF precursor.

[0090] (2) The obtained Ni-MOF precursor was placed in a ceramic boat, and then the ceramic boat was placed in the constant temperature zone of a tube furnace. Nitrogen gas was introduced at a flow rate of 100 mL / min, and the temperature was increased to 650 °C at a rate of 10 °C / min. After holding the temperature for 120 min, the heating was stopped, and the temperature was cooled to room temperature under a nitrogen atmosphere to obtain carbon-coated nickel catalyst.

[0091] (3) The elemental analyzer determined that the nanomaterial contained 54.23% C, 0.74% H, and 3.06% O, and the normalized Ni content was 41.97%.

[0092] The carbon layer in this composite material has many defects, resulting in significant losses during acid washing.

[0093] The following examples illustrate a method for preparing 1,4-butenediol from 1,4-butynediol.

[0094] Example 1

[0095] 80 mg of the carbon-coated nickel nanocomposite material prepared in Example 1, 8 mg of dicyandiamine, 430 mg of 1,4-butynediol, and 30 mL of ethanol (95% by volume) were added to a reaction vessel (the mass ratio of carbon-coated nickel nanocomposite material to dicyandiamine was 1:0.1, and the mass ratio of carbon-coated nickel nanocomposite material to 1,4-butynediol was 1:5.4). After purging the reaction vessel with H2 four times, H2 was introduced again to bring the pressure inside the reaction vessel to 1.0 MPa. The temperature was raised to the predetermined reaction temperature of 70°C, and the reaction was continued for 45 min. Heating was then stopped, and the mixture was allowed to cool to room temperature before depressurization. The product was then removed from the reaction vessel for chromatographic analysis. The conversion rate of the reactants and the selectivity of the target product were calculated using the following formula:

[0096] Conversion rate (%) = (Mass of reactants reacted / Amount of reactants added) × 100%

[0097] Selectivity (%) = (Mass of target product / Mass of reaction product) × 100%

[0098] Analysis revealed that the conversion rate of 1,4-butynediol was 91.1%, and the selectivity of 1,4-butenediol was 83.4%.

[0099] Example 2

[0100] The carbon-coated nickel nanocomposite material obtained in Preparation Example 1 was used as a catalyst and thiophene as an additive for the catalytic hydrogenation of 1,4-butynediol to 1,4-butenediol.

[0101] The specific experimental steps are similar to those in Application Example 1, except that 8 mg of dicyandiamine is replaced with 80 μL of thiophene and the reaction time is 130 min.

[0102] Analysis revealed that the conversion rate of 1,4-butynediol was 92.4%, and the selectivity of 1,4-butenediol was 85.8%.

[0103] Example 3

[0104] The carbon-coated nickel nanocomposite material obtained in Example 1 was used as a catalyst, and dicyandiamine was used as an additive to catalyze the hydrogenation of 1,4-butynediol to 1,4-butenediol. The specific experimental steps are as follows:

[0105] 40 mg of carbon-coated nickel nanocomposite material, 14 mg of dicyandiamine, 430 mg of 1,4-butynediol, and 30 mL of ethanol (95%) were added to a reaction vessel (the mass ratio of carbon-coated nickel nanocomposite material to dicyandiamine was 1:0.35, and the mass ratio of carbon-coated nickel nanocomposite material to 1,4-butynediol was 1:10.75). After purging the reaction vessel with H2 four times, H2 was introduced again to bring the pressure inside the reaction vessel to 1.0 MPa. The temperature was raised to the predetermined reaction temperature of 80 °C, and the reaction was continued for 65 min before heating was stopped. After cooling to room temperature, the pressure was released, the reaction vessel was opened, and the product was taken out for chromatographic analysis.

[0106] Analysis revealed that the conversion rate of 1,4-butynediol was 99.4%, and the selectivity of 1,4-butenediol was 85.6%.

[0107] Example 4

[0108] The carbon-coated nickel nanocomposite material obtained in Example 1 was used as a catalyst, and dicyandiamine was used as an additive, to catalyze the hydrogenation of 1,4-butynediol to 1,4-butenediol. The specific experimental steps are as follows:

[0109] 80 mg of carbon-coated nickel nanocomposite material, 10 mg of dicyandiamine, 860 mg of 1,4-butynediol, and 30 mL of deionized water were added to a reaction vessel (the mass ratio of carbon-coated nickel nanocomposite material to dicyandiamine was 1:0.125, and the mass ratio of carbon-coated nickel nanocomposite material to 1,4-butynediol was 1:10.75). After purging the reaction vessel with H2 four times, H2 was introduced again to bring the pressure inside the reaction vessel to 2.0 MPa. The temperature was raised to the predetermined reaction temperature of 50 °C, and the reaction was continued for 140 min. Heating was then stopped, and the pressure was released after cooling to room temperature. The product was then taken out of the reaction vessel for chromatographic analysis.

[0110] Analysis revealed that the conversion rate of 1,4-butynediol was 89.0%, and the selectivity of 1,4-butenediol was 86.8%.

[0111] Example 5

[0112] The method was the same as in Example 1, except that the carbon-coated nickel nanocomposite material obtained in Example 2 was used as a catalyst, dicyandiamine was used as an additive, and the reaction time was 85 min.

[0113] Analysis revealed that the conversion rate of 1,4-butynediol was 90.7%, and the selectivity of 1,4-butenediol was 87.9%.

[0114] Example 6

[0115] The method was followed as in Example 1, except that the carbon-coated nickel nanocomposite material obtained in Comparative Preparation Example 1 was used as the catalyst, dicyandiamine was used as the additive, and the reaction time was 60 min.

[0116] Analysis revealed that the conversion rate of 1,4-butynediol was 90.7%, and the selectivity of 1,4-butenediol was 80.4%.

[0117] Example 7

[0118] The method is the same as in Example 1, except that the amount of dicyandiamine used is 120 mg, and the mass ratio of carbon-coated nickel nanocomposite material to dicyandiamine is 1:1.25.

[0119] After the reaction time was the same, analysis showed that the conversion rate of 1,4-butynediol was 58.2% and the selectivity of 1,4-butenediol was 91.8%.

[0120] Comparative Example 1

[0121] The method was the same as in Example 1, except that no additives were added and the reaction time was 40 minutes.

[0122] Analysis revealed a conversion rate of 90.5% for 1,4-butynediol and a selectivity of 74.6% for 1,4-butenediol. Compared with Examples 1 and 2, it can be seen that, under conditions without additives and with a similar conversion rate of 1,4-butynediol, the target product 1,4-butenediol yielded less than 80%, significantly lower than the selectivity of Examples 1 and 2.

[0123] Comparative Example 2

[0124] The method was followed as in Example 3, except that no additives were added and the reaction time was 32 minutes.

[0125] Analysis revealed a conversion rate of 96.5% for 1,4-butynediol and a selectivity of 79.2% for 1,4-butenediol. It can be seen that, with a conversion rate lower than that of Example 3, the selectivity of the target product, 1,4-butenediol, was also lower than that of Example 3.

[0126] Comparative Example 3

[0127] The method was followed as in Example 3, except that 14 mg of dicyandiamine was replaced with 14 mg of urea, and the reaction time was 60 min.

[0128] Analysis revealed a conversion rate of 99.3% for 1,4-butynediol and a selectivity of 75.4% for 1,4-butenediol. This indicates that replacing dicyandiamine with urea did not significantly improve the selectivity for the product 1,4-butenediol.

[0129] Comparative Example 4

[0130] The method was followed as in Example 4, except that 10 mg of dicyandiamine was replaced with 200 μL of 25 wt% ammonia water, and the reaction time was 180 min.

[0131] Analysis revealed that the conversion rate of 1,4-butynediol was 86.4%, and the selectivity of 1,4-butenediol was 75.6%. It can be seen that replacing dicyandiamine with ammonia did not significantly improve the selectivity for 1,4-butenediol.

[0132] As can be seen from the above examples and comparative examples, using the carbon-coated nickel nanocomposite material of the present invention as a catalyst, and dicyandiamine and / or thiophene as additives, the synthesis of 1,4-butynediol from 1,4-butenediol can proceed smoothly within a wide temperature and pressure range, and the selectivity of 1,4-butenediol can reach more than 80%. The catalytic performance of the material is stable, exhibiting good repeatability, high activity and high selectivity.

[0133] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing 1,4-butenediol from 1,4-butynediol, characterized in that, The method includes selectively hydrogenating 1,4-butynediol by contacting it with hydrogen in the presence of a catalytic composition; The catalytic composition includes a carbon-coated nickel nanocomposite material and a catalytic additive; the carbon-coated nickel nanocomposite material includes a nickel nanoparticle core and a graphitized carbon layer shell covering the surface of the nickel nanoparticle core, and the lattice structure of the nickel nanoparticles includes a face-centered cubic lattice structure and / or a close-packed hexagonal lattice structure. The catalytic additive is dicyandiamine and / or thiophene; the selective hydrogenation temperature is 40-100℃; In the catalytic composition, the mass ratio of carbon-coated nickel nanocomposite material to catalytic additive is 1:0.02-1; The preparation method of the carbon-coated nickel nanocomposite material includes: S1, a nickel source, a poly-organic carboxylic acid and a first solvent are mixed to form a homogeneous solution, and then the first solvent in the homogeneous solution is removed to obtain a precursor; S2, the precursor is subjected to high-temperature pyrolysis under an inert protective atmosphere and / or a reducing atmosphere; The organic acid is selected from at least one of ethylenediaminetetraacetic acid, iminodiacetic acid, diethylenetriaminepentaacetic acid, 1,3-propanediaminetetraacetic acid, citric acid, maleic acid, pyromellitic acid, terephthalic acid, and malic acid.

2. The method according to claim 1, wherein, In the catalytic composition, the mass ratio of carbon-coated nickel nanocomposite material to catalytic additive is 1:0.05-0.5; And / or, the method for preparing the catalytic composition includes: mixing carbon-coated nickel nanocomposite material and catalytic additives.

3. The method according to claim 1 or 2, wherein, The average particle size of the carbon-coated nickel nanocomposite material is 1-200 nm; And / or, the carbon-coated nickel nanocomposite material has at least one mesoporous distribution peak; And / or, in the carbon-coated nickel nanocomposite material, the proportion of mesopore volume to total pore volume is greater than 50%; And / or, the pickling loss rate of the carbon-coated nickel nanocomposite material is ≤40%; And / or, based on the total amount of carbon-coated nickel nanocomposites, the content of Ni is 20-85 wt%, the content of C is 14-79 wt%, the content of O is 0.3-6 wt%, the content of N is 0-6 wt%, and the content of H is 0.1-2.5 wt%.

4. The method according to claim 3, wherein, The average particle size of the carbon-coated nickel nanocomposite material is 3-100 nm. And / or, the carbon-coated nickel nanocomposite material has two distribution peaks with mesopore sizes of 2-5 nm and 8-12 nm; And / or, in the carbon-coated nickel nanocomposite material, the proportion of mesopore volume to total pore volume is greater than 80%; And / or, the pickling loss rate of the carbon-coated nickel nanocomposite material is ≤30%.

5. The method according to claim 4, wherein, The average particle size of the carbon-coated nickel nanocomposite material is 4-50 nm. And / or, the pickling loss rate of the carbon-coated nickel nanocomposite material is ≤10%.

6. The method according to claim 1 or 2, wherein, The nickel source is at least one of nickel organic acid salts, carbonates, and basic carbonates; And / or, the organic acid is citric acid; And / or, the molar ratio of the nickel source, calculated as nickel element, to the polycarboxylic acid, calculated as carboxylate, is 1:2-10; And / or, the first solvent is water and / or ethanol.

7. The method according to claim 6, wherein, The nickel source is an organic carboxylate of nickel; And / or, the molar ratio of the nickel source, calculated as nickel element, to the polycarboxylic acid, calculated as carboxylate, is 1:2-6; And / or, the first solvent is water.

8. The method according to claim 7, wherein, The nickel source is nickel acetate; And / or, the molar ratio of the nickel source, calculated as nickel element, to the polycarboxylic acid, calculated as carboxylate, is 1:2-4.

9. The method according to claim 1 or 2, wherein, In step S2, the high-temperature pyrolysis includes: heating the precursor to the temperature of the high-temperature pyrolysis under an inert protective atmosphere and / or a reducing atmosphere, and maintaining the temperature at a constant temperature.

10. The method according to claim 9, wherein, The heating rate is 1-20℃ / min, the constant temperature is 400-800℃, and the constant temperature time is 1-360min.

11. The method according to claim 10, wherein, The heating rate is 2-10℃ / min; the constant temperature is 450-700℃; and the constant temperature time is 10-180min.

12. The method according to claim 9, wherein, The inert atmosphere is provided by at least one of nitrogen, argon, neon and helium; And / or, the reducing atmosphere is hydrogen.

13. The method according to claim 1 or 2, wherein, The preparation method of the carbon-coated nickel nanocomposite material further includes: contacting the product of the high-temperature pyrolysis with an acidic solution to remove the incompletely coated Ni core.

14. The method according to claim 13, wherein, The acidic solution is selected from at least one of aqueous solutions of hydrochloric acid, sulfuric acid, and hydrofluoric acid.

15. The method according to claim 14, wherein, The concentration of the acidic solution is 0.1-3 mol / L.

16. The method according to claim 1 or 2, wherein, The method involves selectively hydrogenating 1,4-butynediol by contacting it with hydrogen in the presence of a catalytic composition and a second solvent.

17. The method according to claim 16, wherein, The second solvent is selected from at least one of water, alcohols, ethers and alkanes.

18. The method according to claim 16, wherein, The amount of the second solvent used is such that the concentration of 1,4-butynediol is 5-600 g / L.

19. The method according to claim 18, wherein, The amount of the second solvent used is such that the concentration of 1,4-butynediol is 10-500 g / L.

20. The method according to claim 1 or 2, wherein, The amount of the catalytic composition and 1,4-butynediol used is such that the mass ratio of carbon-coated nickel nanocomposite material to 1,4-butynediol is 1:1-50.

21. The method according to claim 20, wherein, The amount of the catalytic composition and 1,4-butynediol used is such that the mass ratio of carbon-coated nickel nanocomposite material to 1,4-butynediol is 1:2-40.

22. The method according to claim 1 or 2, wherein, The selective hydrogenation pressure is 0.5-4 MPa.

23. The method according to claim 22, wherein, The pressure for selective hydrogenation is 1-3 MPa.

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