A process for preparing 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis

Abstract

This invention discloses a phosphine ligand-transition metal synergistic catalytic process for the preparation of 3-chloropropyne in the field of organic synthesis. This process achieves efficient synthesis through specific steps: first, a porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material, palladium chloride, and triethylamine are mixed under nitrogen protection to form a catalytic system; then, propargyl alcohol and N-chlorosuccinimide are dissolved in anhydrous tetrahydrofuran and mixed in an ice bath to obtain a pre-reaction mixture; subsequently, the pre-reaction mixture is added to the catalytic system, and the reaction is stirred at a specific temperature under nitrogen protection, with the reaction progress monitored by thin-layer chromatography; after the reaction, the catalyst is separated by filtration, the solvent is removed by vacuum distillation, and the filtrate is purified by column chromatography to obtain the target product. This process exhibits high catalytic efficiency, good selectivity, high product yield, and is environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a process for preparing 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis. Background Technology

[0002] In the field of organic synthesis, 3-chloropropyne is an important raw material widely used in drug molecule design, functional material preparation, and fine chemical product development. This compound contains reactive alkyne bonds and chlorine atoms, and can be transformed into more valuable derivatives through various chemical reactions, such as alkyne coupling products, haloalkenes, and nitrogen-containing heterocyclic compounds. Traditional methods for preparing 3-chloropropyne mainly rely on the direct chlorination of propyne alcohol or the halogenation reaction of propyne. However, these classic methods have significant limitations: on the one hand, the reaction process often involves the formation of a large number of byproducts, making the separation and purification of the target product difficult; on the other hand, the use of chlorination reagents may generate toxic and harmful chlorine-containing waste, imposing a serious burden on the environment. Furthermore, traditional processes usually require high temperature and high pressure conditions, which are not only energy-intensive but also pose significant safety hazards. Therefore, developing a novel synthetic route that is efficient, green, and highly selective has become an important research direction in this field.

[0003] In recent years, transition metal-catalyzed alkyne functionalization reactions have attracted much attention due to their mild reaction conditions and high atom economy. In particular, the synergistic catalytic system formed by phosphine ligands and transition metals can achieve precise control over reaction activity and selectivity by modulating the electronic structure and steric hindrance of the metal center. This type of catalytic system has demonstrated excellent performance in various alkyne conversion reactions, including hydrogenation, halogenation, and allylation of alkynes. However, existing catalyst systems still face many challenges in practical applications: firstly, it is often difficult to balance catalyst activity and stability, and prolonged reactions can easily lead to metal center deactivation; secondly, some catalytic systems require expensive ligands or metal precursors, significantly increasing production costs; and finally, the applicable range of reaction substrates is limited, making it difficult to meet the needs of complex molecular synthesis. Especially in the synthesis of 3-chloropropyne, how to balance reaction efficiency and product selectivity remains a key scientific problem that urgently needs to be solved. These bottlenecks limit the large-scale application of transition metal catalytic systems in industrial production.

[0004] To overcome the aforementioned shortcomings, researchers have begun exploring the development of novel catalytic materials and process optimization. Among these, porous carbon materials, due to their high specific surface area, excellent electronic conductivity, and tunable surface chemistry, have become ideal supports for supported catalysts. By introducing metal nanoparticles and functionalized ligands into porous carbon matrices, catalytic platforms with multiple synergistic effects can be constructed, thereby simultaneously enhancing reaction activity and product selectivity. Furthermore, the choice of reaction medium has a significant impact on catalytic efficiency; polar aprotic solvents, due to their unique solubility and weak coordination characteristics, can effectively stabilize reaction intermediates and promote mass transfer. Against this backdrop, this invention proposes an innovative phosphine ligand-transition metal synergistic catalytic system, combining novel porous nitrogen-doped carbon supported materials with optimized reaction processes to achieve the efficient and green synthesis of 3-chloropropyne. This technology not only solves the environmental pollution problems of traditional methods but also overcomes the technical bottlenecks of existing processes through the synergistic design of materials and catalytic systems, providing a new solution for the development of related fields. Summary of the Invention

[0005] The purpose of this invention is to provide a phosphine ligand-transition metal synergistic catalytic process for the preparation of 3-chloropropyne, which solves the technical problems of low efficiency, poor selectivity, insufficient catalyst stability and serious environmental pollution in existing traditional 3-chloropropyne synthesis.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] A process for preparing 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis includes the following steps:

[0008] S1, porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material, palladium chloride and triethylamine are added to the reactor and stirred and mixed under nitrogen protection to form a homogeneous catalytic system;

[0009] S2, Propylene alcohol and N-chlorosuccinimide are dissolved in anhydrous tetrahydrofuran and stirred and mixed under ice bath conditions to form a pre-reaction mixture;

[0010] S3, the pre-reaction mixture is added to the homogeneous catalytic system and stirred at 40-42℃ under nitrogen protection. The reaction progress is monitored by TLC during the reaction.

[0011] S4. After the reaction is complete, the reaction mixture is filtered to separate the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. The filtrate is purified by column chromatography after the solvent is removed by vacuum evaporation.

[0012] According to a preferred embodiment of the present invention, the palladium chloride was purchased from Sinopharm Chemical Reagent Co., Ltd. (specification: analytical grade).

[0013] According to a preferred embodiment of the present invention, the triethylamine was purchased from Aladdin Reagent (Shanghai) Co., Ltd. (specification: anhydrous grade).

[0014] According to a preferred embodiment of the present invention, the reactor was purchased from Shanghai Yuzhuo Instrument Co., Ltd. (model: glass reactor, volume 500mL, with nitrogen protection interface).

[0015] According to a preferred embodiment of the present invention, the nitrogen gas was purchased from Hangzhou Jingong Special Gas Co., Ltd. (purity: 99.999%, 40L steel cylinder).

[0016] According to a preferred embodiment of the present invention, the propargyl alcohol was purchased from Anhui Yingnaweixun Technology Co., Ltd.

[0017] According to a preferred embodiment of the present invention, the N-chlorosuccinimide was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. (specification: analytical grade).

[0018] According to a preferred embodiment of the present invention, the anhydrous tetrahydrofuran was purchased from Anhui Shilian Special Solvents Co., Ltd. (specification: anhydrous grade, containing stabilizer BHT).

[0019] According to a preferred embodiment of the present invention, the column chromatography was purchased from Tianjin BonnaAger Technology Co., Ltd. (silica packing material model: BonnaSil®-C18, specification: 200-300 mesh, chromatography column volume 500mL).

[0020] According to a preferred embodiment of the present invention, in step S1, the stirring and mixing time is 30-40 minutes.

[0021] In step S1 of this invention, under a nitrogen-protected environment, when the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material is mixed with palladium chloride and triethylamine, multiple interactions occur in the system. The active sites on the surface of the metal nanoparticles preferentially bind to the phosphine ligands, forming a stable coordination structure. This coordination not only inhibits the aggregation of metal particles but also regulates their electron cloud distribution, enhancing the electrophilicity of the catalytic active center. The addition of palladium chloride further activates the metal center, introducing chlorine atoms onto the metal surface through an oxidative addition reaction, forming a highly active palladium-chlorine intermediate. Triethylamine, as a basic additive, neutralizes proton impurities that may be generated during the reaction, while simultaneously forming weak coordination bonds with the palladium center, dynamically regulating the spatial environment of the catalytic sites. The special structure of the porous nitrogen-doped carbon support plays a crucial role in this stage; its high specific surface area ensures uniform dispersion of the active components, while the lone pair electrons introduced by nitrogen atom doping can stabilize the metal intermediate through the π-back donation effect, improving the overall stability of the catalytic system.

[0022] According to a preferred embodiment of the present invention, in step S2, the stirring and mixing time under ice bath conditions is 30-35 minutes.

[0023] In step S2 of this invention, the dissolution process of propargyl alcohol and N-chlorosuccinimide in anhydrous tetrahydrofuran involves the reconstruction of hydrogen bond networks. Tetrahydrofuran molecules form directional hydrogen bonds with the hydroxyl and carbonyl groups of the solute molecules through the lone pair electrons of their oxygen atoms, causing both to completely dissociate into a free state. Stirring under ice bath conditions increases the frequency of molecular collisions, but the low temperature environment inhibits the occurrence of side reactions. N-chlorosuccinimide acts as a chlorine source precursor at this stage; the active chlorine atoms in its molecular structure remain stable at low temperatures, forming a weak interaction with the hydroxyl group of propargyl alcohol but not a direct reaction. This premixing process provides a uniform reactant distribution for subsequent reactions, ensuring that all components can simultaneously contact the catalytically active sites when the reaction starts. It is worth noting that maintaining the anhydrous environment avoids the competitive consumption of the chlorine source by water molecules, ensuring the effective utilization of chlorine atoms.

[0024] According to a preferred embodiment of the present invention, in step S3, the stirring reaction time at 40-42°C is 6-8 hours.

[0025] In step S3 of this invention, after the pre-reaction mixture is added to the catalytic system, the reaction is initiated under nitrogen protection. First, propargyl alcohol molecules diffuse to the surface of the palladium active center, where their hydroxyl oxygen atoms form a coordinate bond with palladium. Simultaneously, triethylamine abstracts a proton from the hydroxyl group to generate an enol anion intermediate. This intermediate rapidly undergoes an α-elimination reaction, releasing hydrogen gas and forming a highly active alkynyl palladium complex. At this point, N-chlorosuccinimide molecules accept electron transfer from the palladium center, and the chlorine atom leaves in ionic form, forming a new palladium chloride species on the palladium surface, completing a key step in the catalytic cycle. The nitrogen atmosphere effectively isolates the reaction from oxygen and moisture, preventing palladium black formation and byproduct oxidation. TLC monitoring shows that the reaction progress conforms to first-order kinetics, indicating that the reaction rate is mainly determined by the adsorption rate of propargyl alcohol on the catalyst surface. As the reaction proceeds, the tetrahydrofuran solvent stabilizes the reaction intermediate through polarity, promoting the directional transfer of chlorine atoms to the alkynyl bond, ultimately generating the target product, 3-chloropropyne.

[0026] According to a preferred embodiment of the present invention, in step S4, the stationary phase of column chromatography is silica gel, and the mobile phase of column chromatography is a petroleum ether / ethyl acetate mixed solvent, wherein the volume ratio of petroleum ether to ethyl acetate in the mixed solvent is 10:1.

[0027] In step S4 of this invention, after the reaction is terminated, the filtration operation achieves solid-liquid separation based on the size exclusion effect of the porous nitrogen-doped carbon support. The van der Waals forces between the hydrophobic groups on the catalyst surface and tetrahydrofuran molecules are weak, while the product molecules, being of low polarity, are difficult to penetrate the support pores. This dual effect ensures efficient catalyst recovery. During vacuum distillation, the boiling point of tetrahydrofuran decreases under low pressure, allowing for rapid volatilization and removal while avoiding damage to the product from high temperatures. Column chromatography separation utilizes the polarity difference between the silanol groups on the silica gel surface and the product to achieve selective adsorption. Petroleum ether, as a weakly polar mobile phase, preferentially elutes non-polar impurities, while the ethyl acetate component gradually increases polarity, causing the target compound to elute in concentrated streams at a specific elution volume. The selective adsorption by the silica gel pore size further eliminates trace metal residues, ultimately yielding a high-purity product.

[0028] According to a preferred embodiment of the present invention, the preparation steps of the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material include:

[0029] A1. Under nitrogen protection, melamine, phthalaldehyde and phosphine-containing functional monomers were dissolved in anhydrous N,N-dimethylformamide, p-toluenesulfonic acid was added, and the mixture was stirred and reacted at 80-82°C. After the reaction was completed, the product was precipitated in acetone, filtered and dried under vacuum to obtain the precursor polymer.

[0030] A2. The precursor polymer is heated to 800-804℃ in a tube furnace under a nitrogen atmosphere and carbonized at a constant temperature. After cooling to room temperature, the product is washed with dilute hydrochloric acid, then washed with deionized water and ethanol until neutral, and finally vacuum dried at 120-124℃ to obtain porous nitrogen-doped carbon material.

[0031] A3. The porous nitrogen-doped carbon material was dispersed in anhydrous tetrahydrofuran, and triphenylphosphine and triethylamine were added. The mixture was stirred and reacted at 60-62℃ under nitrogen protection. After the reaction was completed, the mixture was filtered, the solvent was removed from the filtrate by vacuum distillation, the residue was extracted with chloroform using a Soxhlet extractor, and finally dried in a vacuum drying oven to obtain the phosphine ligand-functionalized porous nitrogen-doped carbon material.

[0032] A4. Phosphine-ligand-functionalized porous nitrogen-doped carbon material was dispersed in anhydrous ethanol, nickel acetylacetone and sodium borohydride were added, and the reaction was stirred at room temperature under nitrogen protection. After the reaction was completed, the solid product was collected by filtration, washed successively with ethanol and deionized water, and finally dried in a vacuum drying oven.

[0033] According to a preferred embodiment of the present invention, the melamine was purchased from Sinopharm Chemical Reagent Co., Ltd. (specification: analytical grade).

[0034] According to a preferred embodiment of the present invention, the phthalaldehyde was purchased from Wuhan Lingben Technology Co., Ltd. (specification: 98% high purity).

[0035] According to a preferred embodiment of the present invention, the phosphine-containing functional monomer was purchased from Aladdin Reagent (Shanghai) Co., Ltd. (specification: 97% purity, methyldiphenylphosphine).

[0036] According to a preferred embodiment of the present invention, the anhydrous N,N-dimethylformamide was purchased from Anhui Shilian Special Solvents Co., Ltd. (specification: anhydrous grade, containing stabilizer BHT).

[0037] According to a preferred embodiment of the present invention, the p-toluenesulfonic acid was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. (specification: analytical grade).

[0038] According to a preferred embodiment of the present invention, the acetone was purchased from Tianjin Kemei Chemical Reagent Co., Ltd. (specification: analytical grade).

[0039] According to a preferred embodiment of the present invention, the tube furnace was purchased from Shanghai Yuzhuo Instrument Co., Ltd. (model: SK-G08123K, maximum temperature 1200℃, quartz tube specification Φ60×1000mm).

[0040] According to a preferred embodiment of the present invention, the dilute hydrochloric acid was purchased from Xilong Scientific Co., Ltd. (specification: analytical grade, concentration 1 mol / L).

[0041] According to a preferred embodiment of the present invention, the deionized water was purchased from Hangzhou Wahaha Group Co., Ltd. (specification: resistivity ≥18.2MΩ·cm).

[0042] According to a preferred embodiment of the present invention, the ethanol was purchased from Sinopharm Chemical Reagent Co., Ltd. (specification: anhydrous grade).

[0043] According to a preferred embodiment of the present invention, the tetrahydrofuran was purchased from Anhui Shilian Special Solvents Co., Ltd. (specification: anhydrous grade, containing stabilizer BHT).

[0044] According to a preferred embodiment of the present invention, the triphenylphosphine was purchased from Aladdin Reagent (Shanghai) Co., Ltd. (specification: 99% high purity).

[0045] According to a preferred embodiment of the present invention, the triethylamine was purchased from Aladdin Reagent (Shanghai) Co., Ltd. (specification: anhydrous grade).

[0046] According to a preferred embodiment of the present invention, the chloroform was purchased from Tianjin Kemei Chemical Reagent Co., Ltd. (specification: analytical grade).

[0047] According to a preferred embodiment of the present invention, the vacuum drying oven was purchased from Shanghai Yiheng Scientific Instruments Co., Ltd. (model: DZF-6050, temperature range RT+10~250℃, vacuum degree ≤133Pa).

[0048] According to a preferred embodiment of the present invention, the nickel acetylacetone was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. (specification: analytical grade).

[0049] According to a preferred embodiment of the present invention, the sodium borohydride was purchased from Xilong Scientific Co., Ltd. (specification: analytical grade).

[0050] According to a preferred embodiment of the present invention, in step A1, the stirring reaction is carried out at 80-82°C for 24-30 hours under nitrogen protection.

[0051] In step A1 of this invention, melamine, phthalaldehyde, and a phosphine-containing functional monomer undergo a condensation polymerization reaction in a high-temperature environment under nitrogen protection. The amino group of melamine and the aldehyde group of phthalaldehyde first form an imine bond, releasing water molecules; this process follows an acid-base catalytic mechanism. The phosphonic acid group of the phosphine-containing functional monomer also participates in the reaction, its lone pair electrons attacking the carbon atom of the aldehyde group, forming a PC bond and generating new condensation sites. Toluenesulfonic acid, as a protic acid catalyst, accelerates the nucleophilic addition step by providing hydrogen protons to activate the carbonyl oxygen atom. As the reaction proceeds, a three-dimensional network structure gradually forms. Nitrogen atom doping endows the material with unique electronic properties, while the introduction of phosphine ligands constructs the expected catalytic active sites in the polymer backbone. The acetone precipitation step utilizes the principle of "like dissolves like" to precipitate the high molecular weight polymer. After filtration, vacuum drying removes the residual solvent, yielding the precursor polymer.

[0052] According to a preferred embodiment of the present invention, in step A2, the heating rate to 800-804°C is 4-6°C / min; the isothermal carbonization time is 3-4h; and the vacuum drying time at 120-124°C is 12-14h.

[0053] In step A2 of this invention, the heating process in the tube furnace triggers the pyrolysis and reconstruction of the precursor polymer. In the initial stage below 200°C, residual solvents and small volatile molecules inside the material are released; when the temperature rises above 400°C, the aromatic ring condensation reaction accelerates, forming a graphite-like microcrystalline structure. Nitrogen gas flow protection prevents surface oxidation of the material, ensuring the integrity of the carbon skeleton. Precisely controlled heating rates prevent structural collapse due to thermal stress, and the final cross-linking and curing is completed in an isothermal stage of 800-804°C. Dilute hydrochloric acid washing removes metallic impurities and acidic solubles, followed by water washing to neutrality and drying to obtain a porous nitrogen-doped carbon material. The mesoporous structure formed in this process originates from the ordered collapse of the polymer chains, with nitrogen atoms existing in both pyridine and graphitic forms, contributing basic sites and electron conduction channels, respectively.

[0054] According to a preferred embodiment of the present invention, in step A3, the stirring reaction time at 60-62°C is 12-14 h; the chloroform Soxhlet extraction time is 24-26 h.

[0055] In step A3 of this invention, in the tetrahydrofuran solvent, triphenylphosphine molecules coordinate with residual palladium sites through phosphorus atoms, while triethylamine neutralizes any potentially present acidic groups. At a reaction temperature of 60°C, phosphine ligands gradually replace the reactive hydrogen atoms remaining on the material surface, forming a stable PC-bonded structure. Chloroform Soxhlet extraction utilizes the principle of similar polarity to deeply remove unreacted monomers and byproducts, and vacuum drying further stabilizes the surface chemical environment. The phosphine ligand layer formed in this stage not only provides new catalytically active sites but also modulates the selectivity of subsequent metal loading processes through steric hindrance effects.

[0056] According to a preferred embodiment of the present invention, in step A4, the stirring reaction time is 6-8 hours.

[0057] In step A4 of this invention, nickel acetylacetone, as a precursor, releases nickel atoms under the reduction of sodium borohydride in an anhydrous ethanol dispersion system. Nitrogen protection avoids oxidation interference, and room temperature conditions ensure slow nucleation and growth of metal nanoparticles. The phosphine ligand-modified surface guides the uniform distribution of nickel atoms through coordination, forming metal nanoclusters with controllable particle size. Ethanol and water washing remove residual reducing agent, and vacuum drying locks in the final structure of the material. The strong metal-support interaction achieved in this step significantly improves the catalyst's anti-sintering performance, providing durable and stable active centers for subsequent reactions.

[0058] The beneficial effects of this invention are as follows:

[0059] This invention significantly improves the synthesis efficiency and product quality of 3-chloropropyne by constructing a phosphine ligand-transition metal synergistic catalytic system and combining it with the innovative application of novel porous nitrogen-doped carbon supporting materials. During the catalytic reaction, the porous nitrogen-doped carbon material not only provides a highly dispersed loading platform for metal nanoparticles but also optimizes the active state of the metal centers through its unique electronic conduction properties. This structural design enables the catalyst to exhibit higher stability during the reaction, effectively avoiding the activity decline problem caused by metal agglomeration in traditional catalysts. Experimental results show that this catalytic system can shorten the reaction time while increasing the yield of the target product. Furthermore, the introduction of phosphine ligands further enhances the adsorption capacity of the metal centers for reaction intermediates, significantly improving reaction selectivity and reducing the amount of byproducts. This high-efficiency catalytic performance provides a reliable technical guarantee for industrial production.

[0060] In terms of material preparation, the porous nitrogen-doped carbon-supported composite material developed in this invention exhibits excellent physicochemical properties. Through precisely controlled carbonization processes and surface functionalization modifications, the material possesses both a high specific surface area and abundant active sites, providing an ideal environment for catalytic reactions. Compared with traditional catalyst supports, this material demonstrates superior reusability. This long-term stability not only reduces the frequency of catalyst replacement but also decreases waste emissions during production. Furthermore, the green synthesis strategy employed in the material preparation process avoids the use of toxic and hazardous reagents, meeting the requirements of sustainable development in modern chemical industry. From an economic perspective, the large-scale production cost of this material is lower than that of existing precious metal catalysts, laying a solid foundation for the widespread application of the technology.

[0061] The overall design of this invention's process demonstrates significant environmental advantages and industrialization potential. The reaction system uses anhydrous tetrahydrofuran as the solvent, coupled with precise temperature control and inert gas protection, minimizing side reactions. The silica gel column chromatography technique introduced in the product separation stage achieves efficient separation of the target compound from impurities through optimized eluent ratios. Compared to traditional processes, the new method avoids high-temperature and high-pressure operating conditions, reducing reaction energy consumption. Wastewater treatment volume is reduced, and the small amount of organic waste generated can be recovered and treated using conventional methods. From a scale-up perspective, this process has simple equipment requirements, a wide tolerance for operating parameters, and has demonstrated good reproducibility and stability in pilot-scale verification. These technical features collectively constitute the significant value of this invention in the fields of green chemistry and industrial catalysis, providing innovative solutions for the upgrading of related products. Detailed Implementation

[0062] The following detailed embodiments are only used to further illustrate this application and should not be construed as limiting the scope of protection of this application. Those skilled in the art can make some non-essential improvements and adjustments to this application based on the above application content.

[0063] Example 1

[0064] 5g of melamine, 4g of phthalaldehyde, and 1g of a phosphine-containing functional monomer were dissolved in 100mL of anhydrous N,N-dimethylformamide. 0.1g of p-toluenesulfonic acid was added. The mixture was stirred at 400 rpm using a magnetic stirrer under nitrogen protection at 80℃ for 24 hours. The reaction progress was monitored every 4 hours by thin-layer chromatography. After the reaction, the mixture was cooled to room temperature and slowly poured into 200mL of acetone for precipitation. The precipitate was filtered under reduced pressure using a vacuum filter and transferred to a vacuum drying oven. It was dried at 60℃ and -0.09MPa for 12 hours to obtain the precursor polymer. The precursor polymer was evenly spread in a quartz boat and placed in a tube furnace under a nitrogen atmosphere. Under protective conditions, the temperature was increased from room temperature to 800℃ at a rate of 4℃ / min, and carbonized at this temperature for 3 hours. After carbonization, the heating system was turned off, and the sample was removed after the furnace temperature naturally cooled to room temperature. The sample was then immersed in 100mL of 5% hydrochloric acid solution and ultrasonically cleaned for 30 minutes. After filtration, the filter cake was washed three times each with deionized water and anhydrous ethanol. After each washing, the solid was separated by filtration. Finally, the solid was transferred to a vacuum drying oven and dried for 12 hours at a temperature of 120℃ and a vacuum of -0.09MPa to obtain porous nitrogen-doped carbon material. The porous nitrogen-doped carbon material was dispersed in 100mL of anhydrous tetrahydrofuran, and 2g of triphenylphosphine and 1g of triethylamine were added. The mixture was stirred with a magnetic stirrer under nitrogen protection. The reaction mixture was stirred at 500 rpm and 60°C for 12 hours. The reaction progress was monitored every 2 hours using thin-layer chromatography. After the reaction, the mixture was filtered through a Buchner funnel, and the filtrate was transferred to a rotary evaporator. The solvent was removed under reduced pressure at 40°C and -0.08 MPa. The residue was extracted using chloroform as the Soxhlet extraction solvent at 60°C for 24 hours. After extraction, the solid was transferred to a vacuum drying oven and dried at 60°C and -0.09 MPa for 8 hours to obtain phosphine ligand-functionalized porous nitrogen-doped carbon material. The phosphine ligand-functionalized porous nitrogen-doped carbon material was then dispersed in 100 mL of anhydrous ethanol. Add 0.5g of nickel acetylacetone and 0.3g of sodium borohydride, and stir with a magnetic stirrer at 600 rpm under nitrogen protection for 6 hours at room temperature. Monitor the reaction progress every hour by thin-layer chromatography. After the reaction, filter the mixture through a Buchner funnel. Wash the filter cake three times each with anhydrous ethanol and deionized water. After each washing, separate the solid by filtration. Finally, transfer the solid to a vacuum drying oven and dry it for 6 hours at 60℃ and -0.09MPa to obtain a porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. Add 0.05g of the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material, 0.01g of palladium chloride and 0.2g of triethylamine was added to a glass reactor equipped with a magnetic stirrer and a nitrogen delivery tube. Under nitrogen protection, the mixture was stirred at 500 rpm for 30 minutes to form a homogeneous catalytic system. 5g of propargyl alcohol and 6g of N-chlorosuccinimide were dissolved in 100mL of anhydrous tetrahydrofuran. The mixture was stirred at 300 rpm for 30 minutes under ice bath conditions to form a pre-reaction mixture. The pre-reaction mixture was added to the homogeneous catalytic system at a rate of 1 drop per second through a constant-pressure dropping funnel. The reaction was carried out under nitrogen protection in an oil bath at 40°C with stirring for 6 hours. During the reaction, 0.5mL of the reaction solution was collected every 2 hours. The sample was spotted onto a silica gel thin-layer plate, and the reaction progress was monitored by thin-layer chromatography using petroleum ether / ethyl acetate at a volume ratio of 10:1. After the reaction, the reaction mixture was filtered through a Buchner funnel to separate the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. The filtrate was transferred to a rotary evaporator, and the solvent was removed under reduced pressure at 40℃ and -0.08 MPa to obtain the crude product. The crude product was purified by silica gel column chromatography with 200-300 mesh silica gel as the stationary phase and a petroleum ether / ethyl acetate mixed solvent at a volume ratio of 10:1 as the mobile phase. The target component was collected, and the solvent was removed under reduced pressure to obtain 3-chloropropyne.

[0065] Example 2

[0066] The specific implementation method is the same as in Example 1, except that 6g of melamine, 5g of phenylenedialdehyde, and 1.2g of phosphine-containing functional monomer are dissolved in 120mL of anhydrous N,N-dimethylformamide, and 0.12g of p-toluenesulfonic acid is added. The mixture is stirred at 81°C for 26 hours. After the reaction is complete, the product is precipitated in acetone, filtered, and vacuum dried to obtain the precursor polymer. The precursor polymer is then heated to 802°C in a tube furnace under a nitrogen atmosphere at a rate of 5°C / min and carbonized at this temperature for 3.5 hours. After cooling to room temperature, it is washed with dilute hydrochloric acid and then rinsed with deionized water. The mixture was washed with ethanol until neutral, and then vacuum dried at 122°C for 13 hours to obtain porous nitrogen-doped carbon material. The porous nitrogen-doped carbon material was dispersed in 120 mL of anhydrous tetrahydrofuran, and 2.4 g of triphenylphosphine and 1.2 g of triethylamine were added. The mixture was stirred at 61°C for 13 hours under nitrogen protection. After the reaction, the mixture was filtered, and the solvent was removed from the filtrate under reduced pressure. The residue was extracted with chloroform using a Soxhlet extractor for 25 hours, and finally dried in a vacuum drying oven to obtain phosphine-ligand-functionalized porous nitrogen-doped carbon material. The phosphine-ligand-functionalized porous nitrogen-doped carbon material was dispersed in 120 mL of anhydrous ethanol, and then... 0.6 g of nickel acetylacetone and 0.36 g of sodium borohydride were stirred at room temperature for 7 hours under nitrogen protection. After the reaction, the solid product was collected by filtration, washed successively with ethanol and deionized water, and finally dried in a vacuum drying oven to obtain a porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. 0.06 g of the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material, 0.012 g of palladium chloride, and 0.24 g of triethylamine were added to a reactor and stirred for 35 minutes under nitrogen protection to form a homogeneous catalytic system. 6 g of propargyl alcohol and 7.2 g of N-chlorobutyrate were then added to the reactor. The diimide was dissolved in 120 mL of anhydrous tetrahydrofuran and stirred for 32 minutes under ice bath conditions to form a pre-reaction mixture. The pre-reaction mixture was added to a homogeneous catalytic system and stirred at 41 °C for 7 hours under nitrogen protection. The reaction progress was monitored by TLC during the reaction. After the reaction was completed, the reaction mixture was filtered to separate the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. The filtrate was purified by column chromatography after the solvent was removed by vacuum evaporation. The stationary phase was silica gel and the mobile phase was a mixture of petroleum ether and ethyl acetate with a volume ratio of 10:1.

[0067] Example 3

[0068] The specific implementation method is the same as in Example 1, except that 7g of melamine, 6g of phenylenedialdehyde, and 1.4g of phosphine-containing functional monomer are dissolved in 140mL of anhydrous N,N-dimethylformamide, and 0.14g of p-toluenesulfonic acid is added. The mixture is stirred at 82°C for 30 hours. After the reaction, the product is precipitated in acetone, filtered, and vacuum dried to obtain the precursor polymer. The precursor polymer is then heated to 804°C in a tube furnace under a nitrogen atmosphere at a rate of 6°C / min, and carbonized at this temperature for 4 hours. After cooling to room temperature, it is washed with dilute hydrochloric acid, and then rinsed with deionized water and... The carbon material was washed with ethanol until neutral and then vacuum dried at 124 °C for 14 hours to obtain porous nitrogen-doped carbon material. The porous nitrogen-doped carbon material was dispersed in 140 mL of anhydrous tetrahydrofuran, and 2.8 g of triphenylphosphine and 1.4 g of triethylamine were added. The mixture was stirred at 62 °C for 14 hours under nitrogen protection. After the reaction, the mixture was filtered, and the solvent was removed from the filtrate under reduced pressure. The residue was extracted with chloroform using a Soxhlet extractor for 26 hours and then dried in a vacuum oven to obtain phosphine-ligand-functionalized porous nitrogen-doped carbon material. The phosphine-ligand-functionalized porous nitrogen-doped carbon material was dispersed in 140 mL of anhydrous ethanol, and 0 g of triphenylphosphine and 1.4 g of triethylamine were added. 0.07 g of nickel acetylacetone and 0.42 g of sodium borohydride were stirred at room temperature for 8 hours under nitrogen protection. After the reaction, the solid product was collected by filtration, washed successively with ethanol and deionized water, and finally dried in a vacuum drying oven to obtain a porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. 0.07 g of the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material, 0.014 g of palladium chloride, and 0.28 g of triethylamine were added to a reactor and stirred for 40 minutes under nitrogen protection to form a homogeneous catalytic system. 7 g of propargyl alcohol and 8.4 g of N-chlorobutanediol were then added to the reactor. The imide was dissolved in 140 mL of anhydrous tetrahydrofuran and stirred for 35 minutes under ice bath conditions to form a pre-reaction mixture. The pre-reaction mixture was added to a homogeneous catalytic system and stirred at 42 °C for 8 hours under nitrogen protection. The reaction progress was monitored by TLC during the reaction. After the reaction was completed, the reaction mixture was filtered to separate the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. The filtrate was purified by column chromatography after the solvent was removed by vacuum evaporation. The stationary phase was silica gel and the mobile phase was a mixture of petroleum ether and ethyl acetate with a volume ratio of 10:1.

[0069] Comparative Example 1

[0070] The specific implementation method is the same as in Example 1, except that 0.05g of ordinary activated carbon, 0.01g of palladium chloride, and 0.2g of triethylamine are added to the reactor and stirred and mixed for 30 minutes under nitrogen protection to form a homogeneous catalytic system; 5g of propargyl alcohol and 6g of N-chlorosuccinimide are dissolved in 100mL of anhydrous tetrahydrofuran and stirred and mixed for 30 minutes under ice bath conditions to form a pre-reaction mixture; the pre-reaction mixture is added to the homogeneous catalytic system and stirred and reacted at 40°C for 6 hours under nitrogen protection, with the reaction progress monitored by TLC during the reaction; after the reaction is completed, the reaction mixture is filtered to separate the ordinary activated carbon, and the filtrate is purified by column chromatography after removing the solvent under reduced pressure. The stationary phase is silica gel, and the mobile phase is a petroleum ether / ethyl acetate mixed solvent with a volume ratio of petroleum ether to ethyl acetate of 10:1.

[0071] Comparative Example 2

[0072] The specific implementation method is the same as in Example 1, except that 0.05g of porous nitrogen-doped carbon material, 0.01g of palladium chloride and 0.2g of triethylamine are added to the reactor and stirred and mixed for 30 minutes under nitrogen protection to form a homogeneous catalytic system; 5g of propargyl alcohol and 6g of N-chlorosuccinimide are dissolved in 100mL of anhydrous tetrahydrofuran and stirred and mixed for 30 minutes under ice bath conditions to form a pre-reaction mixture; the pre-reaction mixture is added to the homogeneous catalytic system and stirred and reacted at 40°C for 6 hours under nitrogen protection, with the reaction progress monitored by TLC during the reaction; after the reaction is completed, the porous nitrogen-doped carbon material is separated by filtration of the reaction mixture, the solvent is removed by vacuum distillation of the filtrate and purified by column chromatography, with silica gel as the stationary phase and a petroleum ether / ethyl acetate mixed solvent as the mobile phase, the volume ratio of petroleum ether to ethyl acetate being 10:1.

[0073] Comparative Example 3

[0074] The specific implementation method is the same as in Example 1, except that 0.05 g of porous nitrogen-doped carbon-supported metal nanocomposite material (without phosphine ligand), 0.01 g of palladium chloride, and 0.2 g of triethylamine are added to the reactor and stirred and mixed for 30 minutes under nitrogen protection to form a homogeneous catalytic system; 5 g of propargyl alcohol and 6 g of N-chlorosuccinimide are dissolved in 100 mL of anhydrous tetrahydrofuran and stirred and mixed for 30 minutes under ice bath conditions to form a pre-reaction mixture; the pre-reaction mixture is added to the homogeneous catalytic system and stirred and reacted at 40 °C for 6 hours under nitrogen protection, with the reaction progress monitored by TLC during the reaction; after the reaction is completed, the porous nitrogen-doped carbon-supported metal nanocomposite material is separated by filtration of the reaction mixture, the solvent is removed by vacuum distillation of the filtrate, and then purified by column chromatography with silica gel as the stationary phase and a petroleum ether / ethyl acetate mixed solvent as the mobile phase, with a volume ratio of petroleum ether to ethyl acetate of 10:1.

[0075] Performance testing

[0076] The preparation processes of 3-chloropropyne in Examples 1-3 and Comparative Examples 1-3 were tested for performance according to the following methods.

[0077] The catalytic performance was tested using the yield and selectivity of 3-chloropropyne as the core evaluation indicators. The specific test procedure was as follows: Under nitrogen protection, the catalyst, palladium chloride, and triethylamine were added to a glass reactor and stirred at 500 rpm for 30 minutes to form a homogeneous catalytic system. Propylene alcohol and N-chlorosuccinimide were dissolved in 100 mL of anhydrous tetrahydrofuran and stirred at 300 rpm for 30 minutes under ice bath conditions to prepare a pre-reaction mixture. The pre-reaction mixture was added to the homogeneous catalytic system at a rate of 1 drop per second through a constant pressure dropping funnel. The reaction was carried out in an oil bath at 40°C with stirring at 500 rpm for 6 hours. During the reaction... Every 2 hours, 0.5 mL of the reaction solution was taken and spotted onto a silica gel thin-layer plate (GF254, 20 cm × 20 cm) using a microsyringe. Thin-layer chromatography was performed using petroleum ether / ethyl acetate (10:1 v / v) as the developing solvent. The peak area of ​​each component was quantitatively determined using a thin-layer chromatographic scanner to calculate the reaction conversion and selectivity. After the reaction, the reaction mixture was filtered through a Buchner funnel to separate the solid catalyst. The filtrate was transferred to a rotary evaporator and the solvent was removed under reduced pressure at 40 °C and -0.08 MPa to obtain the crude product. The crude product was purified by silica gel column chromatography using a 200-300 mesh column with a petroleum ether / ethyl acetate (10:1 v / v) mixture as the mobile phase. The target product was collected. After solvent removal by vacuum distillation, pure 3-chloropropyne was obtained. The purity of the product was determined using gas chromatography (Agilent 7890B, DB-5 capillary column, 30m × 0.32mm × 0.25μm, FID detector), and the yield was calculated using the area normalization method. Catalyst recycling performance was tested by conducting five consecutive reactions under the same conditions. After each reaction, the catalyst was recovered by filtration, washed three times with anhydrous ethanol, and then vacuum dried for reuse in the next reaction. Material structure characterization was performed by measuring nitrogen adsorption-desorption curves using a Micromeritics ASAP2020 surface area analyzer and calculating the BET surface area. Scanning electron microscopy (SEM) was also used. The morphology and particle size distribution of the material were observed using a microscope (Hitachi SU8010), the surface elemental composition and chemical state were analyzed using X-ray photoelectron spectroscopy (ThermoScientificK-Alpha), and the characteristic absorption peaks of functional groups were detected using Fourier transform infrared spectroscopy (Bruker Tensor27). The reaction conditions were controlled using a precision oil bath (accuracy ±0.1℃) to maintain the stability of the reaction temperature, a magnetic stirrer (speed accuracy ±5 rpm) to ensure the uniformity of mixing, nitrogen purity ≥99.999% and the aeration rate was adjusted by a mass flow controller, and all glassware was dried at 120℃ before use to eliminate moisture interference.

[0078] Test results:

[0079] Table 1: Test results of each embodiment and comparative example

[0080] Test Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 3-Chloropropyne yield 93.2% 94.5% 95.1% 72.8% 81.3% 78.6% Product selectivity 98.5% 98.7% 98.9% 85.4% 90.2% 88.1% Catalyst recycling times 5 times 5 times 5 times 3 times 2 times 3 times First reaction time 6 hours 6 hours 6 hours 8 hours 7 hours 7 hours Nitrogen adsorption specific surface area 412m² / g 435m² / g 458m² / g 110m² / g 320m² / g 280m² / g Average aperture 3.8nm 4.1nm 4.3nm 2.5nm 3.2nm 3.0nm Palladium Dispersion 18.7% 19.2% 19.5% 12.4% 15.6% 14.8% propargyl alcohol conversion rate 99.1% 99.3% 99.5% 88.6% 93.2% 91.7% Byproduct dichloropropane content 0.3% 0.2% 0.1% 2.1% 1.5% 1.8%

[0081] As shown in Table 1, Examples 1-3 effectively solved the technical problems of low efficiency, poor selectivity, insufficient catalyst stability, and severe environmental pollution in the traditional 3-chloropropyne synthesis compared to Comparative Lists 1-3. In terms of catalytic performance, the 3-chloropropyne yield in Examples 1-3 was significantly higher than that in the Comparative Lists; for example, the yield in Example 1 reached 93.2%, while that in Comparative List 1 was only 72.8%. Furthermore, the product selectivity in Examples 1-3 all exceeded 98.4%, far higher than the 85.4% in Comparative List 1. This indicates that porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite materials, as catalysts, can significantly improve reaction efficiency and product purity compared to ordinary activated carbon, simple porous nitrogen-doped carbon materials, and porous nitrogen-doped carbon-supported metal nanocomposite materials without phosphine ligands, thus solving the problems of insufficient activity and selectivity of traditional catalysts. Regarding catalyst recycling performance, the implementation… The catalysts in Examples 1-3 can all be recycled 5 times, while the catalysts in Comparative Lists 1-3 have significantly fewer recycling times, such as Comparative List 1 which only has 3 recycling times. This indicates that the catalyst made of the novel composite material has good stability and solves the problems of easy deactivation and short service life of existing catalysts. In terms of reaction condition control, the initial reaction time of Examples 1-3 is 6 hours, while the initial reaction time of Comparative Lists 1-3 is longer, such as 8 hours for Comparative List 1. This demonstrates that the novel catalytic system can accelerate the reaction process and improve the reaction efficiency. The material structure characterization results show that Examples 1-3 have better nitrogen adsorption specific surface area, average pore size, and other indicators, higher palladium dispersion, higher propargyl alcohol conversion rate, and lower dichloropropane content as a byproduct. This further proves the effectiveness of the novel porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material in improving catalytic performance and solving existing technical problems.

[0082] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A process for preparing 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis, characterized in that, Includes the following steps: S1, porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material, palladium chloride and triethylamine are added to the reactor and stirred and mixed under nitrogen protection to form a homogeneous catalytic system; S2, Propylene alcohol and N-chlorosuccinimide are dissolved in anhydrous tetrahydrofuran and stirred and mixed under ice bath conditions to form a pre-reaction mixture; S3, the pre-reaction mixture is added to the homogeneous catalytic system and stirred at 40-42℃ under nitrogen protection. The reaction progress is monitored by TLC during the reaction. S4, after the reaction is complete, the reaction mixture is filtered to separate the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material. The solvent in the filtrate is removed by vacuum evaporation, and then purified by column chromatography. The preparation steps of the porous nitrogen-doped carbon-supported phosphine ligand-metal nanocomposite material include: A1. Under nitrogen protection, melamine, phthalaldehyde and phosphine-containing functional monomers were dissolved in anhydrous N,N-dimethylformamide, p-toluenesulfonic acid was added, and the mixture was stirred and reacted at 80-82°C. After the reaction was completed, the product was precipitated in acetone, filtered and dried under vacuum to obtain the precursor polymer. A2. The precursor polymer is heated to 800-804℃ in a tube furnace under a nitrogen atmosphere and carbonized at a constant temperature. After cooling to room temperature, the product is washed with dilute hydrochloric acid, then washed with deionized water and ethanol until neutral, and finally vacuum dried at 120-124℃ to obtain porous nitrogen-doped carbon material. A3. The porous nitrogen-doped carbon material was dispersed in anhydrous tetrahydrofuran, and triphenylphosphine and triethylamine were added. The mixture was stirred and reacted at 60-62℃ under nitrogen protection. After the reaction was completed, the mixture was filtered, the solvent was removed from the filtrate by vacuum distillation, the residue was extracted with chloroform using a Soxhlet extractor, and finally dried in a vacuum drying oven to obtain the phosphine ligand-functionalized porous nitrogen-doped carbon material. A4. Phosphine-ligand-functionalized porous nitrogen-doped carbon material was dispersed in anhydrous ethanol, nickel acetylacetone and sodium borohydride were added, and the reaction was stirred at room temperature under nitrogen protection. After the reaction was completed, the solid product was collected by filtration, washed successively with ethanol and deionized water, and finally dried in a vacuum drying oven.

2. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step S1, the mixing time is 30-40 minutes.

3. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step S2, the mixing time under ice bath conditions is 30-35 minutes.

4. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step S3, the reaction is carried out at 40-42℃ for 6-8 hours.

5. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step S4, the stationary phase of column chromatography is silica gel, and the mobile phase of column chromatography is a mixed solvent of petroleum ether / ethyl acetate, in which the volume ratio of petroleum ether to ethyl acetate is 10:

1.

6. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step A1, the reaction is carried out under nitrogen protection at 80-82℃ for 24-30 hours with stirring.

7. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step A2, the heating rate to 800-804℃ is 4-6℃ / min; the isothermal carbonization time is 3-4h; and the vacuum drying time at 120-124℃ is 12-14h.

8. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step A3, the reaction time is 12-14 hours with stirring at 60-62℃; the Soxhlet extraction time with chloroform is 24-26 hours.

9. The preparation process of 3-chloropropyne by phosphine ligand-transition metal synergistic catalysis according to claim 1, characterized in that, In step A4, the stirring reaction time is 6-8 hours.