Porous organometallic palladium polymers for selective hydrogenation of terminal propargyl alcohol and methods of making and using the same

Abstract

The application provides a porous organometallic palladium polymer applied to selective hydrogenation of terminal alkynyl propanol, a preparation method and application thereof. The porous organometallic palladium polymer comprises a reaction product of a palladium-based metal organic compound, a comonomer and a crosslinking agent, and the palladium-based metal organic compound is selected from one of bisbenzimidazole nitrogen heterocyclic carbene palladium chloride, bis-triphenylphosphine palladium chloride or tetra-triphenylphosphine palladium. The porous organometallic palladium polymer of the application has the advantages of homogeneous catalysis and heterogeneous catalysis as a catalyst, has the advantages of high catalytic efficiency, good selectivity, wide applicability, easy recovery, greenness, economy and the like, and can realize a series of hydrogenation reactions under ultra-low catalytic amount and mild conditions.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a porous organometallic palladium polymer for selective hydrogenation of terminal propargyl alcohols, its preparation method, and its application. Background Technology

[0002] The selective hydrogenation of terminal alkynes to prepare enols is an important chemical process in the synthesis of many chemicals, such as pharmaceuticals, fragrances, and polymer monomers, including the synthesis of linalool fragrance and isophytol, an intermediate of vitamin E.

[0003] Currently, Lindlar catalysts are commonly used in the selective hydrogenation of alkynols in industry. When adding the catalyst to the reaction system, Pb and quinoline are added for poisoning, and fluorine- and sulfur-containing organic compounds are added as inhibitors. While this improves the selectivity of enols, it also accompanies various side reactions, and the catalyst stability remains poor. The addition of poisoning agents and inhibitors reduces product quality, increases the difficulty of separation and purification, and easily leads to the formation of toxic and harmful residues, limiting the application of chemicals in the pharmaceutical field and violating the requirements of green chemistry and chemical engineering development. Therefore, developing novel, highly efficient, stable, and easily separable catalysts that improve the selectivity of enols and reduce production and purification costs without introducing poisoning agents and inhibitors is a major challenge in the field of semi-hydrogenation.

[0004] With the development of novel catalysts and processes, most catalysts used in the selective hydrogenation of alkynols are supported Pd-based catalysts. CN110124742A discloses a method for the selective hydrogenation of alkynols to prepare enols, using a hydrogenation catalyst modified with a poisoning agent. The poisoning agent is a metal salt or a metal carbonyl compound, preferably iron or zinc; the hydrogenation catalyst is preferably a supported palladium catalyst or a Lindlar catalyst. CN114249629A discloses a method for the selective catalytic hydrogenation of alkynols to synthesize enols, using a PdZn / Meso_S-C catalyst prepared by impregnation with Meso_S-C, which has a high specific surface area and is rich in S, as the support. The active component is an alloy phase formed by Pd-Zn. Although supported palladium catalysts have shown good hydrogenation activity in selective hydrogenation, they require high catalyst dosage and demanding reaction conditions. To achieve higher enol selectivity, meticulous design and control of various aspects, including the catalyst's active metal centers, the role of promoters (second metal, organic ligands, stabilizers), the properties of the support (pore structure, acidity / basicity, strong metal-support interaction), and reaction conditions, are often necessary, increasing the difficulty of catalyst preparation. Furthermore, during recycling, issues such as active center aggregation, shedding, denaturation, and carbon deposition can lead to catalyst deactivation, necessitating regeneration for reuse. This limits their application in enol production, highlighting the urgent need to develop novel catalysts. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a porous organometallic palladium polymer for the selective hydrogenation of terminal propargyl alcohols, its preparation method, and its application. The porous organometallic palladium polymer of this invention, as a catalyst, has advantages such as high catalytic efficiency, good selectivity, wide applicability, easy recovery, greenness, and economy. Its application in the selective hydrogenation of terminal propargyl alcohols to enols under mild conditions meets the requirements of the pharmaceutical, chemical, and materials industries for efficient, green, and economical catalysis.

[0006] In a first aspect, the present invention provides a porous organometallic palladium polymer applicable to the selective hydrogenation of terminal propargyl alcohols, comprising a palladium-based organometallic compound, a comonomer, and a crosslinking agent, wherein the palladium-based organometallic compound is selected from one of bisbenzimidazole nitrogen heterocyclic carbene palladium chloride, bistriphenylphosphine palladium chloride, or tetratriphenylphosphine palladium.

[0007] In some embodiments, the palladium-based organometallic compound is selected from bisbenzimidazole nitrogen heterocyclic carbene palladium chloride and / or tetratriphenylphosphine palladium.

[0008] Homogeneous palladium-based organometallic compounds have stable structures and can achieve catalytic cycling at ultra-low catalytic amounts (down to ppm levels). Moreover, the activity and selectivity of the metal center can be adjusted by simply regulating the steric hindrance and electronic properties of the ligands. They also exhibit excellent performance in the selective hydrogenation of alkynes, with olefin selectivity reaching over 99%, and can control the cis-trans ratio of olefins well. However, homogeneous palladium-based organometallic compounds are difficult to separate as catalysts, which is not conducive to industrial applications.

[0009] The inventors of this application have discovered through research that a porous organometallic palladium polymer formed by directly immobilizing a homogeneous palladium-based organometallic compound with a defined structure, stable performance, excellent catalytic activity and selectivity, and easy controllability and modification, combines the advantages of homogeneous catalysis and heterogeneous catalysis. It can achieve the selective hydrogenation of terminal propargyl alcohols to enols under ultra-low catalytic amounts and mild conditions. This porous organometallic palladium polymer, as a catalyst, can solve the problem that homogeneous palladium-based organometallic compounds are difficult to separate as catalysts, which is not conducive to industrial applications.

[0010] In some embodiments, the comonomer is selected from C6-C with or without substituent R. 20 Aromatic compounds, wherein the substituent R is selected from deuterium, halogen, methyl, ethyl, propyl, isopropyl, cyano or amino.

[0011] In some embodiments, the comonomer is benzene with or without a substituent R, wherein the substituent R is selected from deuterium, fluorine, chlorine, bromine, methyl, ethyl, propyl, or isopropyl.

[0012] In some embodiments, the comonomer is benzene.

[0013] In some embodiments, the crosslinking agent is selected from dimethoxymethane.

[0014] In some embodiments, the molar ratio of the comonomer to the palladium-based organometallic compound is (2-10):1; for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1 or any value between them.

[0015] In some embodiments, the molar ratio of the comonomer to the palladium-based organometallic compound is (2-4):1.

[0016] In some embodiments, the molar ratio of the crosslinking agent to the palladium-based organometallic compound is (15-25):1; for example, 15:1, 18:1, 20:1, 21:1, 24:1 or any value between them.

[0017] In a second aspect, the present invention provides a method for preparing the porous organometallic palladium polymer described in the first aspect of the present invention, comprising the following steps:

[0018] Palladium-based organometallic compounds, comonomers, crosslinking agents, catalysts, and solvents were mixed under an inert atmosphere and subjected to a copolymerization reaction.

[0019] The palladium-based organometallic compound is selected from one of bisbenzimidazole nitrogen heterocyclic carbene palladium chloride, bistriphenylphosphine palladium chloride, or tetratriphenylphosphine palladium.

[0020] In some embodiments, the palladium-based organometallic compound is selected from bisbenzimidazole nitrogen heterocyclic carbene palladium chloride and / or tetratriphenylphosphine palladium.

[0021] In some embodiments, the porous organometallic palladium polymer is prepared as follows:

[0022]

[0023] In some embodiments, the catalyst is selected from Lewis acids.

[0024] In some embodiments, the Lewis acid is selected from one or more of ferric chloride, aluminum chloride, sulfuric acid, or boron trifluoride ether.

[0025] In some embodiments, the Lewis acid is selected from ferric chloride and / or aluminum chloride.

[0026] In some embodiments, the catalyst is ferric chloride.

[0027] In some embodiments, the solvent is one or more of dichloromethane, trichloromethane, 1,2-dichloroethane, or carbon tetrachloride.

[0028] In some embodiments, the solvent is 1,2-dichloroethane.

[0029] In some embodiments, the temperature of the copolymerization reaction is 50-100°C; for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C or any value between them, preferably 60-90°C.

[0030] In some embodiments, the copolymerization reaction takes 12-48 hours, for example 15 hours, 20 hours, 24 hours, 29 hours, 34 hours, 40 hours, or 45 hours, preferably 18-36 hours.

[0031] In some embodiments, the concentration of the palladium-based organometallic compound in the solvent is 0.01-5 mol / L; for example, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, or any value between them. By fixing the amounts of other reagents (comonomers, crosslinking agents, catalysts) and solvent, and adjusting the structure and concentration of the palladium-based organometallic compound, a series of porous organometallic palladium polymers with different active metal structures, contents, specific surface areas, and hydrogen adsorption capacities can be obtained.

[0032] In some embodiments, the concentration of the palladium-based organometallic compound in the solvent is 0.05-0.5 mol / L.

[0033] In some embodiments, the concentration of the palladium-based organometallic compound in the solvent is 0.1 mol / L.

[0034] In some embodiments, the molar ratio of the catalyst to the palladium-based organometallic compound is (15-25):1; for example, 15:1, 18:1, 20:1, 21:1, 24:1 or any value between them.

[0035] In some embodiments, the preparation method further includes a post-processing step: filtering, washing, Soxhlet extracting, and vacuum drying the solid product obtained from the copolymerization reaction.

[0036] In some embodiments, the vacuum drying temperature is 50-80°C, for example 50°C, 60°C, 70°C, 80°C or any value between them.

[0037] In some embodiments, the inert atmosphere is selected from nitrogen.

[0038] Thirdly, the present invention provides an application of the porous organometallic palladium polymer described in the first aspect of the present invention or the porous organometallic palladium polymer obtained by the preparation method described in the second aspect of the present invention in the selective hydrogenation of terminal propargyl alcohol to prepare terminal allyl alcohol.

[0039] Fourthly, the present invention provides a method for selectively hydrogenating terminal propargyl alcohols to prepare terminal allyl alcohols, comprising the following steps:

[0040] Terminal propargyl alcohol, catalyst and reaction solvent are mixed and selectively hydrogenated in a hydrogen atmosphere to obtain terminal allyl alcohol; the catalyst includes the porous organometallic palladium polymer described in the first aspect of the present invention or the porous organometallic palladium polymer obtained by the preparation method described in the second aspect of the present invention.

[0041] In some embodiments, the terminal propargyl alcohol has the structure shown in Formula I or Formula III, and the terminal allyl alcohol has the structure shown in Formula II or Formula IV;

[0042] I II;

[0043] III IV;

[0044] R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C. 20 Alkyl, substituted or unsubstituted C1-C 20 Alkenyl, substituted or unsubstituted C4-C 10 Cycloalkyl, substituted or unsubstituted C6-C 24 Aryl or substituted or unsubstituted C6-C 24 Mixed aromatics;

[0045] R1 and R2 can be connected to form a substituted or unsubstituted C4-C bond. 10 cycloalkyl;

[0046] n is an integer from 1 to 5, preferably an integer from 1 to 3;

[0047] Wherein, substitution refers to the substitution of one or more hydrogen atoms in a group by a substituent selected from the group consisting of: halogen, C1-C4 alkyl, C1-C4 haloalkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, hydroxyl, amino, and mercapto.

[0048] In some embodiments, R1 and R2 are each independently selected from C1-C5 alkyl groups and C1-C4 alkyl groups substituted with 1-3 C1-C4 alkyl groups. 20 Alkyl, C1-C4 substituted with 1-3 C1-C4 alkyl groups 20 Alkenyl group.

[0049] In some embodiments, R1 and R2 are each independently selected from methyl, ethyl, propyl, isopropyl, and C1-C4 alkyl-substituted compounds. 20 Alkyl, C1-C4 substituted with 1-3 C1-C4 alkyl groups 20 Alkenyl group.

[0050] In some embodiments, R1 is selected from C1-C3 alkyl groups.

[0051] In some embodiments, R1 is selected from methyl, ethyl, propyl, or isopropyl.

[0052] In some embodiments, R2 is selected from C1-C4 alkyl-substituted C1-C4 alkyl groups. 15 Alkyl or C1-C5 alkenyl groups substituted with 1-4 C1-C4 alkyl groups.

[0053] In some embodiments, the terminal propargyl alcohol is selected from dehydrolinalool, dehydroisophytol, or 3-butyn-1-ol. The terminal allyl alcohol obtained from the above-mentioned terminal propargyl alcohol can be directly used to prepare linalool fragrance, or it can be used for further preparation of vitamin E.

[0054] In some embodiments, when the terminal propargyl alcohol is dehydrolinalool, the catalyst is selected from the reaction product of bisbenzimidazole nitrogen heterocyclic carbene palladium chloride, comonomer, and crosslinking agent.

[0055] In some embodiments, when the terminal propargyl alcohol is a dehydrodehydroisophytol, the catalyst is selected from the reaction product of tetraphenylphosphine palladium, comonomer, and crosslinking agent.

[0056] In some embodiments, the selective hydrogenation reaction is completed, followed by cooling and filtration of the catalyst. The catalyst is then used directly in the next reaction without requiring activation.

[0057] In some embodiments, the selective hydrogenation reaction is followed by a purification step: obtaining the terminal allyl alcohol by distillation or column chromatography.

[0058] In some embodiments, the hydrogenation reaction is carried out in a reaction vessel, flask, or autoclave. This invention eliminates the need for special equipment such as glove boxes.

[0059] In some embodiments, the reaction solvent is selected from water, methanol, ethanol, isopropanol, tert-butanol, tetrahydrofuran, dioxane, N,N-dimethylformamide, benzene, toluene, or a combination thereof.

[0060] In some embodiments, the molar ratio of the terminal propargyl alcohol to the catalyst is 10,000-1,000,000:1.

[0061] In some embodiments, the molar ratio of the terminal propargyl alcohol to the catalyst is 80,000-550,000:1.

[0062] In some embodiments, the molar ratio of the terminal propargyl alcohol to the catalyst is 100,000-400,000:1.

[0063] In some embodiments, the molar ratio of the terminal propargyl alcohol to the catalyst is 150,000-250,000:1.

[0064] In some embodiments, the molar ratio of the terminal propargyl alcohol to the catalyst is 450,000-550,000:1.

[0065] In some embodiments, the molar ratio of the terminal propargyl alcohol to the catalyst is 200,000:1.

[0066] In some embodiments, the temperature of the selective hydrogenation reaction is 25-100°C, for example 28°C, 35°C, 45°C, 55°C, 65°C, 70°C, 85°C, or 95°C.

[0067] In some embodiments, the selective hydrogenation reaction is carried out at a temperature of 25°C.

[0068] In some embodiments, the selective hydrogenation reaction takes 0.1-30 hours, for example, 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, or 30 hours.

[0069] In some embodiments, the selective hydrogenation reaction takes 1-3 hours.

[0070] In some embodiments, the selective hydrogenation reaction takes 2 hours.

[0071] In some embodiments, the selective hydrogenation reaction is carried out at a pressure of 1-20 atmospheres, for example, 1 atmosphere, 2 atmospheres, 5 atmospheres, 10 atmospheres, 15 atmospheres, or 20 atmospheres.

[0072] In some embodiments, the selective hydrogenation reaction is carried out at a pressure of 1-5 atmospheres.

[0073] In some embodiments, the selective hydrogenation reaction is carried out at a pressure of 1 atmosphere.

[0074] Fifthly, the present invention provides the use of terminal allyl alcohol prepared by the method described in the fourth aspect of the present invention in the preparation of linalool fragrance and / or the preparation of vitamin E.

[0075] This invention provides a method for selective hydrogenation of terminal propargyl alcohols using a single-point porous organometallic palladium polymer, comprising the following steps:

[0076] Porous organometallic palladium polymer, reactant terminal propargyl alcohol, and solvent are added to a reaction vessel and selectively hydrogenated at a certain temperature in a hydrogen atmosphere. After the reaction is completed, the temperature is lowered and the catalyst is filtered. The corresponding product is obtained by distillation or column chromatography. The catalyst does not need to be activated and can be used directly in the next round of reaction.

[0077] In some embodiments, the reactant terminal propargyl alcohol has the structure shown in Formula I, and the product has the structure shown in Formula II;

[0078] I

[0079] II

[0080] Wherein, R1 is hydrogen, substituted or unsubstituted C1-C. 20 Alkyl or alkenyl, substituted or unsubstituted C4-C 10 Cycloalkyl, substituted or unsubstituted C6-C 24 aryl or heteroaryl;

[0081] R2 is hydrogen, substituted or unsubstituted C1-C. 20 Alkyl or alkenyl, substituted or unsubstituted C4-C 10 Cycloalkyl, substituted or unsubstituted C6-C 24 Aryl or heteroaryl, wherein R1 and R2 can be connected to form a substituted or unsubstituted C4-C group. 10 cycloalkyl;

[0082] Wherein, “substituted” means that one or more hydrogen atoms in the group are replaced by a substituent selected from the group consisting of: halogen, C1-C4 alkyl, C1-C4 haloalkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, hydroxyl, amino, and mercapto.

[0083] In some implementations, the reaction process is as follows:

[0084] .

[0085] In some embodiments, the molar ratio of the terminal propargyl alcohol to the porous organometallic palladium polymer catalyst is 10,000-1,000,000:1.

[0086] In some embodiments, the reaction temperature is 25-100°C and the reaction time is 0.1-30 hours.

[0087] In some implementations, the hydrogen pressure for the reaction is controlled to be 1-20 atmospheres.

[0088] In some embodiments, the solvent required for the reaction is selected from: water, methanol, ethanol, isopropanol, tert-butanol, tetrahydrofuran, dioxane, N,N-dimethylformamide, benzene, toluene, or a combination thereof.

[0089] In some embodiments, when the terminal propargyl alcohol is dehydrolinalool, dehydroisophytol, or 3-butyn-1-ol, the resulting product can be used to prepare linalool fragrance or to further prepare vitamin E.

[0090] In some embodiments, the preparation of the Pd-based solid molecular catalyst includes the following steps:

[0091] (1) A certain concentration of homogeneous palladium-based organometallic compound, benzene, DCE, FDA and FeCl3 were added to a glass bottle filled with nitrogen after vacuuming, and stirred at 80°C for 24 hours to obtain a solid product.

[0092] (2) The solid product obtained in step (1) is filtered, washed, extracted by Soxhlet extraction and then dried under vacuum to obtain the Pd-based solid molecular catalyst.

[0093] In some embodiments, the amounts of benzene, DCE, FDA, and FeCl3 are fixed, and the concentration of the homogeneous Pd precursor is 0.01-5 mol / L.

[0094] In some implementations, the porous organometallic palladium polymer used can be recovered through simple filtration and used directly in the next cycle without activation.

[0095] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0096] This invention uses a structurally stable and high-performance homogeneous palladium-based organometallic compound as a palladium precursor, and directly immobilizes it to form a porous organometallic palladium polymer using a simple and low-cost method. This porous organometallic palladium polymer completely retains the structure of the homogeneous precursor, with highly dispersed metal sites and abundant pore structure. As a catalyst, it combines the advantages of both homogeneous and heterogeneous catalysis, exhibiting not only high catalytic efficiency, good selectivity, wide applicability, easy recovery, greenness, and economy, but also the ability to achieve a series of hydrogenation reactions under ultra-low catalytic dosage and mild conditions. Furthermore, the porous organometallic palladium polymer of this invention is insoluble in ethanol and water, can be recovered through simple filtration without activation, and can be directly used in the next cycle after drying. It can be recycled dozens of times while maintaining stable catalytic activity and selectivity.

[0097] Furthermore, the porous organometallic palladium polymer of the present invention has a wide range of applications. For terminal propargyl alcohol substrates with different chain lengths, steric hindrances, and electrical properties, the porous organometallic palladium polymer of the present invention can selectively convert the substrates into corresponding terminal enol products with high selectivity. Moreover, the catalyst dosage is extremely low, the reaction conditions are mild, and the reaction can be carried out at room temperature and pressure. Through simple filtration recovery, it can be recycled multiple times without activation and regeneration, effectively solving the problems of difficult catalyst control, high dosage, poor selectivity, and the need for activation and regeneration in selective hydrogenation. This provides a green and economical synthetic method for the selective hydrogenation of terminal propargyl alcohols, with very broad industrial application prospects. Attached Figure Description

[0098] Figure 1 The transmission electron microscope (TEM) image and corresponding EDS-Mapping image of Pd-NHC 1b prepared in Example 2 are shown.

[0099] Figure 2 Aberration-corrected electron micrograph of Pd-NHC 1b prepared in Example 2;

[0100] Figure 3 The carbon NMR spectrum of Pd-NHC 1a prepared in Example 1;

[0101] Figure 4 The image shows the XPS characterization of Pd-NHC 1a prepared in Example 1. Detailed Implementation

[0102] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0103] 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.

[0104] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0105] In this invention, room temperature refers to 20-30℃.

[0106] In the application examples and comparative examples of this invention, the pressure of the reaction system is 1-5 atmospheres.

[0107] Example 1: Synthesis of Pd-NHC catalyst

[0108] 1 mmol of a bisbenzimidazole-containing heterocyclic carbene palladium chloride compound (0.65 g) was added to a 50 mL Schlenk tube. The tube was evacuated three times with nitrogen. Then, 10 mL of 1,2-dichloroethane and 3 mmol of benzene (0.23 g) were added sequentially. The mixture was stirred at room temperature until the solid was completely dissolved. Next, 20 mmol of dimethoxymethane (FDA, 1.52 g) and 20 mmol of anhydrous ferric chloride (3.24 g) were added. The mixture was sealed and placed in an oil bath at 80 °C for 24 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, washed, and the resulting solid was subjected to Soxhlet extraction for 24 hours. The solid was then vacuum-dried at 60 °C for 24 hours to obtain the porous organometallic palladium polymer Pd-NHC1a, with a yield of 1.0 g (91%). The structure of the porous organometallic palladium polymer Pd-NHC1a was characterized as follows: Figure 3 and Figure 4 As shown. According to Figure 3 Solid-state NMR spectroscopy shows that the homogeneous precursor structure is largely preserved after solidification; according to Figure 4 XPS characterization showed that the valence state of Pd remained unchanged before and after immobilization, indicating that the immobilization method does not affect the coordination structure of the catalyst.

[0109] Example 2: Synthesis of Pd-NHC catalyst

[0110] 1 mmol of a bisbenzimidazole-containing heterocyclic carbene palladium chloride compound (0.65 g) was added to a 50 mL Schlenk tube. The tube was evacuated to nitrogen three times. Then, 10 mL of 1,2-dichloroethane and 6 mmol of benzene (0.46 g) were added sequentially. The mixture was stirred at room temperature until the solid was completely dissolved. Then, 20 mmol of dimethylformaldehyde (FDA, 1.52 g) and anhydrous ferric chloride (3.24 g) were added. The mixture was sealed and placed in an oil bath at 80 °C for 24 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, washed, and the resulting solid was subjected to Soxhlet extraction for 24 hours. The solid was then dried under vacuum at 60 °C for 24 hours to obtain the porous organometallic palladium polymer Pd-NHC1b. Yield: 1.19 g, 90%. Transmission electron microscopy (TEM) image of Pd-NHC1b is shown below. Figure 1 As shown in (a), the corresponding EDS-Mapping diagram is as follows: Figure 1 As shown in (b), the spherical aberration electron micrograph is as follows: Figure 2 As shown. By Figure 1 and Figure 2 It can be seen that the metal sites in the porous organometallic palladium polymer Pd-NHC1b are highly dispersed.

[0111] Example 3: Synthesis of Pd-NHC catalyst

[0112] 1 mmol of bisbenzimidazole nitrogen-containing heterocyclic carbene palladium chloride compound (0.65 g) was added to a 50 mL Schlenk tube. The tube was evacuated to nitrogen three times. Then, 10 mL of 1,2-dichloroethane and 9 mmol of benzene (0.70 g) were added sequentially. The mixture was stirred at room temperature until the solid was completely dissolved. Next, 20 mmol of dimethylformaldehyde (FDA, 1.52 g) and anhydrous ferric chloride (3.24 g) were added. The mixture was sealed and placed in an oil bath at 80 °C for 24 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, washed, and the resulting solid was extracted using a Soxhlet extract for 24 hours and dried under vacuum at 60 °C for 24 hours to obtain Pd-NHC1c. Yield: 1.40 g, 89%.

[0113] Example 4

[0114] 1 mmol of bis(triphenylphosphine)palladium chloride (0.71 g) was added to a 50 mL Schlenk tube, and the tube was evacuated to nitrogen three times. Then, 10 mL of 1,2-dichloroethane and 3 mmol of benzene (0.23 g) were added sequentially. The mixture was stirred at room temperature until the solid was completely dissolved. Then, 20 mmol of dimethylformaldehyde (FDA, 1.52 g) and anhydrous ferric chloride (3.24 g) were added. The mixture was sealed and placed in an oil bath at 80 °C for 24 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, washed, and the resulting solid was subjected to Soxhlet extraction for 24 hours and then dried under vacuum at 60 °C for 24 hours to obtain the porous organometallic palladium polymer Pd-NHC1d.

[0115] Example 5

[0116] 1 mmol of tetrakis(triphenylphosphine) palladium (1.16 g) was added to a 50 mL Schlenk tube, and the tube was evacuated to nitrogen three times. Then, 10 mL of 1,2-dichloroethane and 3 mmol of benzene (0.23 g) were added sequentially. The mixture was stirred at room temperature until the solid was completely dissolved. Then, 20 mmol of dimethylformaldehyde (FDA, 1.52 g) and anhydrous ferric chloride (3.24 g) were added. The mixture was sealed and placed in an oil bath at 80 °C for 24 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, washed, and the resulting solid was subjected to Soxhlet extraction for 24 hours and then dried under vacuum at 60 °C for 24 hours to obtain the porous organometallic palladium polymer Pd-NHC1e.

[0117] Application Example 1: Effect of different temperatures on the Pd-NHC-catalyzed hydrogenation of dehydrolinalool

[0118] In an air atmosphere, dehydrolinalool (2 mmol, 0.3 g), 2 mg of the porous organometallic palladium polymer Pd-NHC 1b solid catalyst, and 10 mL of ethanol were added to a Schlenk tube equipped with a magnetic stirrer. The mixture was purged three times with high-purity hydrogen, and then the reaction system was stirred in an oil bath at 30 °C for a certain period of time. After the reaction was completed, the Schlenk tube was cooled to room temperature and the pressure was slowly released, and samples were taken for analysis. The catalyst was then separated by filtration and could be recycled. (Results are shown in Table 1.)

[0119] Table 1. Effect of different reaction times on the Pd-NHC1b-catalyzed hydrogenation of dehydrolinalool

[0120]

[0121] Table 1 shows that the reaction time has a certain impact on the rate and selectivity of the hydrogenation reaction. The reaction rate increases linearly with the increase of reaction time. When the reaction time is 90 min, the conversion rate of the reaction is 96.86%, and the selectivity can be maintained as high as 90.94%.

[0122] Application Example 2: Effect of different catalyst dosages on the Pd-NHC-catalyzed dehydrolinalool hydrogenation reaction

[0123] In an air atmosphere, dehydrolinalool (2 mmol, 0.3 g), a certain amount of the solid catalyst porous organometallic palladium polymer Pd-NHC 1b, and 10 mL of ethanol were added to a Schlenk tube equipped with a magnetic stirrer. The tube was purged three times with high-purity hydrogen, and a hydrogen balloon was inserted. The reaction system was then stirred in an oil bath at 30 °C. After the reaction was completed, the Schlenk tube was cooled to room temperature and the pressure was slowly released. Samples were taken for analysis. The catalyst was then separated by filtration and could be recycled. (Results are shown in Table 2.)

[0124] Table 2. Effect of different catalyst dosages on the Pd-NHC 1b-catalyzed dehydrolinalool hydrogenation reaction.

[0125]

[0126] Table 2 shows that different catalyst dosages have a significant impact on the rate and selectivity of the hydrogenation reaction. The selectivity and conversion are highest when the catalyst dosage is 0.001 mol%, while they decrease when the dosage exceeds 0.001 mol%. These results indicate that catalyst dosage is a crucial factor affecting the hydrogenation reaction.

[0127] Application Example 3: The Effect of Different Catalysts on the Catalytic Hydrogenation of Dehydrolinalool

[0128] In an air atmosphere, dehydrolinalool (2 mmol, 0.3 g), 0.001 mol% of the porous organometallic palladium polymer obtained in Examples 2, 4, and 5, and 10 mL of ethanol were added to a Schlenk tube equipped with a magnetic stirrer. The tube was purged three times with high-purity hydrogen, and a hydrogen balloon was inserted. The reaction system was then stirred in an oil bath at 30°C for 90 min. After the reaction was completed, the Schlenk tube was cooled to room temperature and the pressure was slowly released. Samples were taken for analysis. The catalyst was then separated by filtration and could be recycled. The results are shown in Table 3.

[0129] Application Comparative Example 1

[0130] In an air atmosphere, dehydrolinalool (2 mmol, 0.3 g), 0.001 mol% of bisbenzimidazole nitrogen-containing heterocyclic carbene palladium chloride compound, and 10 mL of ethanol were added to a Schlenk tube equipped with a magnetic stirrer. The mixture was purged three times with high-purity hydrogen. The reaction system was then stirred in an oil bath at 30 °C for 90 min. After the reaction was complete, the Schlenk tube was cooled to room temperature and the pressure was slowly released. Samples were taken for analysis. The results are shown in Table 3.

[0131] Table 3

[0132]

[0133] Application Example 4: The Effect of Different Catalysts on the Catalytic Hydrogenation of Dehydrophytol

[0134] In an air atmosphere, dehydroisophytol (2 mmol, 0.59 g), 0.001 mol% of the porous organometallic palladium polymer obtained in Examples 2, 4, and 5, and 10 mL of ethanol were added to a Schlenk tube equipped with a magnetic stirrer. The mixture was purged three times with high-purity hydrogen. The reaction system was then stirred in an oil bath at 30°C for 90 min. After the reaction was complete, the Schlenk tube was cooled to room temperature and the pressure was slowly released. Samples were taken for analysis. The catalyst was then separated by filtration and could be recycled. The results are shown in Table 4.

[0135] Application Example Comparative Example 2

[0136] In an air atmosphere, dehydroisophytol (2 mmol, 0.59 g), 0.001 mol% bisbenzimidazole nitrogen-containing heterocyclic carbene palladium chloride compound, and 10 mL of ethanol were added to a Schlenk tube equipped with a magnetic stirrer. The mixture was purged three times with high-purity hydrogen. The reaction system was then stirred in an oil bath at 30 °C for 90 min. After the reaction was complete, the Schlenk tube was cooled to room temperature and the pressure was slowly released. Samples were taken for analysis. The catalyst was then separated by filtration and could be recycled. The results are shown in Table 4.

[0137] Table 4

[0138]

[0139] As shown in Tables 3 and 4, different catalysts have different catalytic activities. Compared with palladium-based organometallic compounds, the porous organometallic palladium polymer formed by immobilizing palladium-based organometallic compounds in this application has higher catalytic activity, which significantly improves the selectivity and conversion rate of the selective hydrogenation of terminal propargyl alcohol to terminal allyl alcohol.

[0140] 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 terminal allyl alcohol by selectively hydrogenating terminal propargyl alcohol, comprising the following steps: mixing terminal propargyl alcohol, a catalyst and a reaction solvent to perform selective hydrogenation under a hydrogen atmosphere to obtain terminal allyl alcohol; the catalyst comprises a porous organometallic palladium polymer, the porous organometallic palladium polymer comprises a reaction product of a palladium-based metal organic compound, a comonomer and a crosslinking agent, the palladium-based metal organic compound is selected from one of bisbenzimidazole carbene chloride palladium or tetraphenylphosphine palladium; the terminal propargyl alcohol is selected from dehydro-linalool or dehydro-isophytol; when the terminal propargyl alcohol is dehydro-linalool, the catalyst is selected from a reaction product of bisbenzimidazole carbene chloride palladium, a comonomer and a crosslinking agent; when the terminal propargyl alcohol is dehydro-isophytol, the catalyst is selected from a reaction product of tetraphenylphosphine palladium, a comonomer and a crosslinking agent; the comonomer is benzene and the crosslinking agent is dimethoxymethane; the molar ratio of the comonomer to the palladium-based metal organic compound is (2-10) : 1; and / or the molar ratio of the crosslinking agent to the palladium-based metal organic compound is (15-25) :

1. 2.A method for preparing terminal allyl alcohol by selectively hydrogenating terminal propargyl alcohol, comprising the following steps: mixing terminal propargyl alcohol, a catalyst and a reaction solvent to perform selective hydrogenation under a hydrogen atmosphere to obtain terminal allyl alcohol; the catalyst comprises a porous organometallic palladium polymer, the porous organometallic palladium polymer comprises a reaction product of a palladium-based metal organic compound, a comonomer and a crosslinking agent, the palladium-based metal organic compound is selected from one of bisbenzimidazole carbene chloride palladium or tetraphenylphosphine palladium; the terminal propargyl alcohol is selected from dehydro-linalool or dehydro-isophytol; when the terminal propargyl alcohol is dehydro-linalool, the catalyst is selected from a reaction product of bisbenzimidazole carbene chloride palladium, a comonomer and a crosslinking agent; when the terminal propargyl alcohol is dehydro-isophytol, the catalyst is selected from a reaction product of tetraphenylphosphine palladium, a comonomer and a crosslinking agent; the comonomer is benzene and the crosslinking agent is dimethoxymethane; the molar ratio of the comonomer to the palladium-based metal organic compound is (2-4) : 1; and / or the molar ratio of the crosslinking agent to the palladium-based metal organic compound is (15-25) :

1. 3.A method for preparing a porous organometallic palladium polymer, comprising the following steps: mixing a palladium-based metal organic compound, a comonomer, a crosslinking agent, a catalyst and a solvent in an inert atmosphere and performing a copolymerization reaction. 4.The method of claim 3, wherein the catalyst is selected from a Lewis acid; and / or the solvent is one or more of dichloromethane, trichloromethane, 1,2-dichloroethane or carbon tetrachloride; and / or the copolymerization reaction is performed at a temperature of 50-100℃; and / or the copolymerization reaction is performed for a time of 12-48h; and / or the concentration of the palladium-based metal organic compound in the solvent is 0.01-5mol / L; and / or the molar ratio of the catalyst to the palladium-based metal organic compound is (15-25) : 1; and / or the method further comprises a post-processing step of filtering, washing, Soxhlet extracting and vacuum drying the solid product obtained from the copolymerization reaction. 5.The method of claim 3 or 4, wherein the Lewis acid is selected from one or more of ferric chloride, aluminum chloride, sulfuric acid or boron trifluoride etherate. 6.The method of claim 3 or 4, wherein the Lewis acid is selected from ferric chloride and / or aluminum chloride. 7.The method of claim 3 or 4, wherein the Lewis acid is ferric chloride.

2. The method of claim 1, wherein, 8.The method of claim 3 or 4, wherein the solvent is 1,2-dichloroethane. 9.The method of claim 3 or 4, wherein the copolymerization reaction is performed at a temperature of 60-90℃.

3. The method of claim 1, wherein, 10.The method of claim 3 or 4, wherein the copolymerization reaction is performed for a time of 18-36h.

4. The method of claim 1, wherein, 11.The method of claim 3 or 4, wherein the concentration of the palladium-based metal organic compound in the solvent is 0.05-0.5mol / L.

5. The method of claim 4, wherein, 12.The method of claim 3 or 4, wherein the reaction solvent is selected from water, methanol, ethanol, isopropanol, tert-butanol, tetrahydrofuran, dioxane, N,N-dimethylformamide, benzene, toluene or a combination of several thereof; and / or the selective hydrogenation is performed at a temperature of 25-100℃, and / or the selective hydrogenation is performed for a time of 0.1-30h, and / or the selective hydrogenation is performed at a pressure of 1-20atm. ​ ​ ​ ​ ​ ​ ​ 6. The method of claim 5, wherein, ​ 7. The method of claim 5, wherein, ​ 8. The method of claim 5, wherein, ​ 9. The method of claim 5, wherein, ​ 10. The method of claim 5, wherein, ​ 11. The method of claim 5, wherein, ​ 12. The method of claim 5, wherein, ​ 13. The method of claim 1, wherein, ​ ​ ​ ​

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