A catalyst for synthesizing alkynyl acid or alkynyl acid ester compounds and a preparation method thereof

Abstract

This invention relates to the field of chemical synthesis technology, and more particularly to a catalyst for the synthesis of alkyl alkynyl acids or alkyl alkynyl esters and a method for their preparation. The catalyst used in this invention for the synthesis of alkyl alkynyl acids or alkyl alkynyl esters is Ag. x Fe y The catalyst has a silver to iron molar ratio of 9:1 to 1:1, preferably 5:1 to 1:1, and the support is an oxide and / or a molecular sieve. The catalyst of this invention can efficiently convert CO2 into alkyl alkynyl acids or alkyl alkynyl esters under mild conditions, which is of significant research importance.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a catalyst for synthesizing alkyl alkynyl acids or alkyl alkynyl esters and a method for preparing the same. Background Technology

[0002] In recent years, the concentration of the greenhouse gas CO2 in the atmosphere has increased year by year, causing a series of harms to humankind, making CO2 emission reduction an urgent priority. CO2 is also a widely available C1 resource in nature, possessing advantages such as low cost, easy availability, and non-toxicity. Therefore, utilizing carbon dioxide to convert into high-value-added chemicals has dual significance. Carbon dioxide is chemically stable; therefore, capturing, fixing, and converting CO2 into high-value-added chemicals presents a significant challenge. Currently, research on carbon dioxide is not yet mature, with only a small amount of research results translated into industrial production. However, this is still a drop in the ocean compared to the enormous emissions. Furthermore, the chemical products synthesized from carbon dioxide have relatively simple structures and significant limitations. Therefore, exploring new chemical conversion methods for carbon dioxide is imperative.

[0003] One important application of CO2 is the synthesis of industrially valuable alkynyl acids (esters) and their derivatives. Alkynic acids (esters) and their derivatives are an important class of compounds, widely found in bioactive molecules, and are highly valuable intermediates in the chemical and pharmaceutical industries. Traditional methods for synthesizing alkynyl acids include the hydrolysis of bromides and their derivatives, as well as the oxidation of alcohols or aldehydes. The main drawbacks of these conventional methods include stringent reaction conditions, poor compatibility with functionalized groups, and a limited substrate applicability. Compared to traditional routes for synthesizing alkynyl acids, metal-catalyzed carboxylation of terminal alkynes with CO2 has significant advantages. Against this backdrop, numerous scientific experiments have focused on developing various effective carboxylation methods. For example, Fukue et al. used cuprous iodide as a catalyst and potassium carbonate as a base to study the catalytic synthesis of substituted alkynyl esters from terminal alkynes, CO2, and bromoalkanes. Matthias Arndt et al. first reported a catalytic system using a combination of 4,7-diphenyl-1,10-o-diazaphenanthroline [bis(4-fluorophenyl)phosphine]Cu(I) and cuprous nitrate, successfully preparing terminal alkyne acids using this highly active catalyst. Zhang Yugen et al. developed a combined catalytic system of a nitrogen-containing heterocyclic carbene copper complex and a tetramethylethylenediamine Cu(I) complex. Lü Xiaobing et al. discovered a new catalyst, AgI, which effectively improved the reaction efficiency. All these catalysts operate under mild conditions and generally employ cesium carbonate in conjunction with the catalyst. The main steps involve the coordination of the terminal alkyne with silver, followed by cesium carbonate deprotonating the terminal alkyne to form silver alkyne. CO2 then inserts into the C-Ag bond to generate silver alkyneate, which is then converted to cesium alkyneate, and finally hydrolyzed to generate the terminal alkyne acid. Carboxylation of the terminal alkyne can also be carried out without a catalyst, but this requires higher reaction temperatures and CO2 partial pressures. Summary of the Invention

[0004] This invention provides a catalyst for the synthesis of alkyl alkynyl acids or alkyl alkynyl esters and its preparation method. The invention uses a supported Ag-Fe alloy as the catalyst, adheres to the principle of "green chemistry", aims for energy saving and high efficiency, and takes into account "atom economy". It can efficiently convert CO2 into alkyl alkynyl acids or alkyl alkynyl esters under mild conditions, which has important research significance.

[0005] In a first aspect, the present invention provides a heterogeneous catalyst for the one-pot synthesis of alkyl alkynyl acids or alkyl alkynyl esters.

[0006] The catalyst for synthesizing alkyl alkynic acids or alkyl alkynic acid esters provided by the present invention is Ag. x Fe y / carrier, x and y are the molar composition of silver and iron; the molar ratio of silver to iron in the catalyst is 9:1 to 1:1, preferably 5:1 to 1:1;

[0007] The support is an oxide and / or a molecular sieve. This invention provides a highly active and stable heterogeneous catalyst, which is beneficial for the one-pot synthesis of alkyl alkynyl acids or alkyl alkynyl esters.

[0008] According to the catalyst provided by the present invention, the oxide is one or more of SiO2, Al2O3, CeO2, TiO2, and ZrO2, preferably SiO2;

[0009] Alternatively, the molecular sieve may be one or more of MCM-41, ZSM-5, and USY, preferably MCM-41.

[0010] In some embodiments of the present invention, the catalyst support is SiO2 and MCM-41 molecular sieve.

[0011] According to the catalyst provided by the present invention, Ag in the catalyst x Fe y The loading amount is 1–55 wt%, preferably 1–30 wt%, and more preferably 5–20 wt%. Within this loading range, the catalyst exhibits good catalytic performance.

[0012] According to a second aspect of the present invention, a method for preparing a catalyst is provided, wherein the catalyst is Ag. x Fe y / The catalyst preparation method includes the following steps: preparing AgxFe nano-alloy and support into powder, reducing them under a hydrogen atmosphere to obtain a supported nano-Ag-Fe alloy powder catalyst.

[0013] In the reduction step, the hydrogen space velocity is 1000–40000 h⁻¹. -1 The reduction temperature is 50–300℃, and the reduction time is 1–10 h;

[0014] Preferably, the catalyst is the catalyst described above for synthesizing alkyl alkynyl acids or alkyl alkynyl ester compounds.

[0015] According to the catalyst preparation method provided by the present invention, the preparation method of the AgxFey nano-alloy includes: preparing a mixture of silver salt, iron salt, organic base, organic solvent, and anhydrous sodium sulfate, and calcining the mixture;

[0016] The calcination temperature is 200–500℃, and the calcination time is 0.5–5 hours.

[0017] Preferably, the silver salt and iron salt are completely dissolved in the mixture;

[0018] Preferably, the calcined powder is filtered in a hydrazine hydrate solution; more preferably, the concentration of the hydrazine hydrate solution is in the range of 0.01–0.5 mol / L.

[0019] Preferably, the filtered powder is dried, and more preferably, the drying temperature is 50-100°C and the drying time is 2-24 hours.

[0020] According to the method for preparing the catalyst provided by the present invention, the organic solvent is one or more of benzene, toluene, xylene, chlorobenzene, dichlorobenzene, dichloromethane, methanol, ethanol, isopropanol, acetonitrile, pyridine, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide, preferably xylene;

[0021] The organic base is one or more of methylamine, urea, ethylamine, ethanolamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, 1,3-propanediamine, 1,2-propanediamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, benzylamine, cyclohexylamine, o-toluidine, m-toluidine, p-toluidine, diphenylamine, n-hexylamine, and benzidine, preferably n-hexylamine;

[0022] The silver salts and iron salts mentioned are various inorganic metal salts and organic metal salts.

[0023] In some embodiments of the present invention, the catalyst preparation method provided by the present invention includes the following steps:

[0024] (1) Weigh out silver salt and iron salt separately and grind them together in a mortar. After grinding for 0.5 h to 1 h, add organic base, organic solvent and anhydrous sodium sulfate to the mortar and continue grinding for another 0.5 h to 1 h to obtain a mixture. The molar ratio of silver to iron is 9:1 to 1:1, and the volume ratio of organic base to solvent is 1:10 to 1:1. The molar ratio of organic base to the total amount of the two metal salts is 1:1 to 1:3.

[0025] (2) The mixture prepared in step (1) is placed in a heating furnace and calcined at a temperature of 200–500 °C for 0.5–5 h. The calcined solid powder is then placed in a hydrazine hydrate solution with a concentration of 0.01–0.5 mol / L, filtered, and repeated at least three times. Finally, it is dried in a vacuum drying oven at a temperature of 50–100 °C for 2–24 h to obtain Ag. x Fe y Nanoalloys.

[0026] (3) The Ag prepared in step (2) x Fe y The nano-alloy and carrier were thoroughly ground in an agate mortar to obtain a solid powder, with a grinding time of 5–30 min.

[0027] (4) The solid powder obtained in step (3) is loaded into a fixed-bed reactor and reduced under a hydrogen atmosphere to obtain a supported nano-Ag-Fe alloy powder catalyst. The hydrogen space velocity is 1000–40000 h⁻¹. -1 The reduction temperature is 50–300℃, and the reduction time is 1–10h.

[0028] According to a third aspect of the invention, the invention also provides a method for synthesizing alkyl alkynyl acids or alkyl alkynyl esters, wherein the catalyst described above or a regenerated version of the aforementioned catalyst is used.

[0029] According to the method for synthesizing alkyl alkynyl acids or alkyl alkynyl esters provided by the present invention, alkyl alkynyl acids or alkyl alkynyl esters are prepared by reacting aliphatic terminal alkyne compounds and carbon dioxide as raw materials.

[0030] Preferably, the chemical formula of the aliphatic terminal alkyne compound is shown in formula (I):

[0031]

[0032] R1 is selected from C4-C12 alkyl and cycloalkyl groups;

[0033] Preferably, the reaction is carried out at room temperature and pressure;

[0034] Preferably, the reaction temperature is 20–40°C, and more preferably, the reaction temperature is 25–30°C; preferably, the reaction time is 12–48 h, and more preferably, the reaction time is 12–24 h.

[0035] According to the method for synthesizing alkyl alkynyl acids or alkyl alkynyl esters provided by the present invention, in an anhydrous and oxygen-free environment, an aliphatic terminal alkynyl compound and a base are mixed in an organic solvent, carbon dioxide is introduced, and the reaction is carried out under the action of a catalyst to obtain alkyl alkynyl acid compounds.

[0036] Preferably, the alkali is an inorganic alkali; more preferably, the inorganic alkali is one or more of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, tert-butylpotassium, and tert-butylsodium; and even more preferably, the alkali is cesium carbonate and / or tert-butylpotassium.

[0037] Preferably, the organic solvent is one of dichloromethane, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and dimethyl sulfoxide, and more preferably, N,N-dimethylformamide.

[0038] Preferably, the amount of catalyst used in the liquid-phase reaction system is 1–10 g / L, and more preferably, the amount of catalyst used is 2–5 g / L;

[0039] The preferred molar equivalent ratio of the base to the aliphatic terminal alkyne compound is 0.5 to 3.0, and more preferably 1 to 2.0.

[0040] According to the method for synthesizing alkyl alkynic acids or alkyl alkynic acid esters provided by the present invention, the reactants further include haloalkanes R2X;

[0041] Preferably, X is one of F, Cl, Br, and I, and more preferably Br and I;

[0042] Preferably, R2 is selected from C4-C12 alkyl and cycloalkyl groups;

[0043] In some embodiments of the present invention, the synthesis method of the alkyl alkynyl acid or alkyl alkynyl ester compound includes the following steps: In an anhydrous and oxygen-free argon atmosphere, using supported nano-Ag-Fe alloy powder as a catalyst, an aliphatic terminal alkyne compound of formula (I) and a base are mixed in an organic solvent, and carbon dioxide (1 atm) is introduced. The reaction is carried out under certain temperature conditions to obtain the alkyl alkynyl acid compound of formula (II). The amount of catalyst used based on the liquid phase system is 1–10 g / L, preferably 2–5 g / L. The molar equivalent ratio of the base to the aliphatic terminal alkyne compound is 0.5–3.0, more preferably 1–2.0. The reaction temperature is 20–40°C, preferably 25–30°C. The reaction time is 12–48 h, preferably 12–24 h.

[0044] The reaction route is as follows:

[0045]

[0046] The aliphatic terminal alkyne compound R1 is selected from C4-C12 alkyl and cycloalkyl compounds.

[0047] The above-mentioned method for preparing alkyl alkynyl acids or alkyl alkynyl esters involves the following steps for synthesizing alkynyl esters: A haloalkane is added to the reaction system in the previous step, and a one-pot reaction is used to obtain the alkyl alkynyl ester. The reaction route is as follows:

[0048]

[0049] The terminal alkynes R1 and R2 mentioned above are selected from C4-C12 alkyl and cycloalkyl groups.

[0050] In the above-mentioned method for preparing alkyl alkynyl acids or alkyl alkynyl esters, X is one of F, Cl, Br, and I, preferably Br and I. This invention uses a supported Ag-Fe alloy as a catalyst to catalyze the carboxylation coupling reaction of terminal alkynes, carbon dioxide, and haloalkanes in a one-pot process under mild conditions, efficiently converting CO2 into alkynyl ester products, which has significant research value.

[0051] In the above-mentioned method for preparing an alkyl alkynyl acid or alkyl alkynyl ester compound, the molar ratio of the raw material aliphatic terminal alkyne compound to the haloalkanes is 1:1 to 1.7, preferably 1:1 to 1.5.

[0052] The beneficial effects of this invention are:

[0053] 1. This invention uses carbon dioxide as a reaction substrate to synthesize alkyl alkynyl acids or alkyl alkynyl esters, providing a direction for the chemical utilization and emission reduction of greenhouse gases.

[0054] 2. This invention uses a supported catalyst based on Ag-Fe alloy powder for the synthesis of alkyl alkynyl acids or alkyl alkynyl esters. The catalyst has high activity, good stability, and can be reused more than 5 times.

[0055] 3. The strong interaction between the silver-iron alloy catalyst and the support in this invention promotes the adsorption of aliphatic terminal alkynes and carbon dioxide on its surface, thereby activating C≡O and increasing the reaction rate.

[0056] 4. The catalyst of this invention can be separated by filtration, and the separation method is simple. The catalyst can be reused after washing and drying.

[0057] 5. The method of this invention for synthesizing alkyl alkynyl acids or alkyl alkynyl esters has simple post-processing methods, high yield of target products, and easy catalyst recovery and reuse. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0059] Example 1: Preparation of catalyst Ag3Fe1 / MCM-41

[0060] Measure 2 mL of n-hexylamine and 10 mL of xylene into a 50 mL beaker and mix thoroughly. Then, weigh 6 mmol (1.0194 g) of AgNO3 and 2 mmol (0.4838 g) of Fe(NO3)3 and add them to the mixture, stirring magnetically until completely dissolved. After complete dissolution, grind the mixture with 80 g of anhydrous sodium sulfate in a mortar. Then, place the mixture in a tube furnace and react at 300 °C for 1 h. After cooling to room temperature, dissolve the resulting solid powder in a 0.1 mol / L hydrazine hydrate solution, wash, filter, and repeat at least three times. Finally, dry in a vacuum drying oven at 80 °C for 12 h to obtain the Ag3Fe1 alloy powder catalyst.

[0061] Weigh 0.3g of Ag3Fe1 nano-alloy powder and 2.7g of MCM-41 molecular sieve synthesized in the above process, grind them thoroughly in an agate mortar for 30 min, and reduce them with hydrogen at 200℃ for 4 h with a hydrogen space velocity of 10000 h⁻¹. -1 A supported nano-Ag3Fe1 / MCM-41 alloy powder catalyst was prepared.

[0062] Example 2: Preparation of catalyst Ag9Fe1 / ZSM-5

[0063] 1.8 mL of ethylenediamine and 18 mL of xylene were separately measured and poured into a 50 mL beaker and mixed thoroughly. Then, 9 mmol (1.5291 g) of AgNO3 and 1 mmol (0.2419 g) of Fe(NO3)3 were weighed and added to the mixture, and stirred magnetically until completely dissolved. After complete dissolution, the mixture was ground and mixed with 80 g of anhydrous sodium sulfate in a mortar. The mixture was then placed in a tube furnace and reacted at 200 °C for 2 h. After cooling to room temperature, the resulting solid powder was dissolved in a 0.1 mol / L hydrazine hydrate solution, washed, filtered, and repeated at least three times. Finally, the powder was dried in a vacuum drying oven at 80 °C for 12 h to obtain the Ag9Fe1 alloy powder catalyst.

[0064] Weigh 0.3g of Ag9Fe1 nano-alloy powder and 2.7g of ZSM-5 molecular sieve synthesized in the above process, grind them thoroughly in an agate mortar for 30 min, and reduce them with hydrogen at 200℃ for 2 h with a hydrogen space velocity of 5000 h⁻¹. -1 A supported nano-Ag9Fe1 / ZSM-5 alloy powder catalyst was prepared.

[0065] Example 3: Preparation of catalyst Ag7Fe1 / USY

[0066] Measure 2 mL of o-toluidine and 2 mL of toluene into a 50 mL beaker and mix thoroughly. Then, weigh 7 mmol (1.1893 g) of AgNO3 and 1 mmol (0.2419 g) of Fe(NO3)3 and add them to the mixture, stirring magnetically until completely dissolved. After complete dissolution, grind the mixture with 80 g of anhydrous sodium sulfate in a mortar. Then, place the mixture in a tube furnace and react at 400 °C for 1 h. After cooling to room temperature, dissolve the resulting solid powder in a 0.1 mol / L hydrazine hydrate solution, wash, filter, and repeat at least three times. Finally, dry in a vacuum drying oven at 80 °C for 12 h to obtain the Ag7Fe1 alloy powder catalyst.

[0067] Weigh 0.3g of Ag7Fe3 nano-alloy powder and 1.7g of USY molecular sieve synthesized in the above process, grind them thoroughly in an agate mortar for 30 min, and reduce them with hydrogen at 200℃ for 2 h with a hydrogen space velocity of 15000 h⁻¹. -1 A supported nano-Ag7Fe1 / USY alloy powder catalyst was prepared.

[0068] Example 4: Preparation of the catalyst Ag5Fe1 / SiO2

[0069] 1.5 mL of triethanolamine and 6 mL of ethanol were separately measured and poured into a 50 mL beaker and mixed thoroughly. Then, 10 mmol (1.699 g) of AgNO3 and 2 mmol (0.4838 g) of Fe(NO3)3 were weighed and added to the mixture, and stirred magnetically until completely dissolved. After complete dissolution, the mixture was ground with 80 g of anhydrous sodium sulfate in a mortar. The mixture was then placed in a tube furnace and reacted at 300 °C for 1 h. After cooling to room temperature, the resulting solid powder was dissolved in a 0.1 mol / L hydrazine hydrate solution, washed, filtered, and repeated at least three times. Finally, the powder was dried in a vacuum drying oven at 80 °C for 12 h to obtain the Ag5Fe1 alloy powder catalyst.

[0070] Weigh 0.3g of Ag5Fe1 nano-alloy powder and 1.2g of SiO2 synthesized in the above process and grind them thoroughly in an agate mortar for 20 min. Then reduce them with hydrogen at 300℃ for 4 h with a hydrogen space velocity of 20000 h⁻¹. -1 A supported nano-Ag5Fe1 / SiO2 alloy powder catalyst was prepared.

[0071] Example 5: Preparation of catalyst Ag1Fe1 / Al2O3

[0072] Measure 2 mL of n-hexylamine and 4 mL of xylene into a 50 mL beaker and mix thoroughly. Then, weigh 5 mmol (0.8495 g) of AgNO3 and 5 mmol (1.2095 g) of Fe(NO3)3 and add them to the mixture, stirring magnetically until completely dissolved. After complete dissolution, grind the mixture with 80 g of anhydrous sodium sulfate in a mortar. Then, place the mixture in a tube furnace and react at 500 °C for 0.5 h. After cooling to room temperature, dissolve the resulting solid powder in 0.1 mol / L hydrazine hydrate solution, wash, filter, and repeat at least three times. Finally, dry in a vacuum drying oven at 80 °C for 12 h to obtain the Ag1Fe1 alloy powder catalyst.

[0073] Weigh 0.3g of Ag1Fe1 nano-alloy powder and 0.7g of Al2O3 synthesized in the above process and grind them thoroughly in an agate mortar for 20 min. Then reduce them with hydrogen at 300℃ for 1 h with a hydrogen space velocity of 10000 h⁻¹. -1 A supported nano-Ag1Fe1 / Al2O3 alloy powder catalyst was prepared.

[0074] Example 6: Preparation of the catalyst Ag3Fe1 / TiO2

[0075] Measure 2 mL of n-hexylamine and 12 mL of xylene into a 50 mL beaker and mix thoroughly. Then, weigh 6 mmol (1.0194 g) of AgNO3 and 2 mmol (0.4838 g) of Fe(NO3)3 and add them to the mixture, stirring magnetically until completely dissolved. After complete dissolution, grind the mixture with 80 g of anhydrous sodium sulfate in a mortar. Then, place the mixture in a tube furnace and react at 200 °C for 2 h. After cooling to room temperature, dissolve the resulting solid powder in a 0.1 mol / L hydrazine hydrate solution, wash, filter, and repeat at least three times. Finally, dry in a vacuum drying oven at 80 °C for 12 h to obtain the Ag3Fe1 alloy powder catalyst.

[0076] Weigh 0.3g of Ag3Fe1 nano-alloy powder and 0.3g of TiO2 synthesized in the above process and grind them thoroughly in an agate mortar for 20 min. Then reduce them with hydrogen at 300℃ for 1 h with a hydrogen space velocity of 15000 h⁻¹. -1 A supported nano-Ag3Fe1 / TiO2 alloy powder catalyst was prepared.

[0077] Example 7: Preparation of the catalyst Ag3Fe1 / ZrO2

[0078] Measure 2 mL of n-hexylamine and 16 mL of xylene into a 50 mL beaker and mix thoroughly. Then, weigh 6 mmol (1.0194 g) of AgNO3 and 2 mmol (0.4838 g) of Fe(NO3)3 and add them to the mixture, stirring magnetically until completely dissolved. After complete dissolution, grind the mixture with 80 g of anhydrous sodium sulfate in a mortar. Then, place the mixture in a tube furnace and react at 400 °C for 1 h. After cooling to room temperature, dissolve the resulting solid powder in a 0.1 mol / L hydrazine hydrate solution, wash, filter, and repeat at least three times. Finally, dry in a vacuum drying oven at 80 °C for 12 h to obtain the Ag3Fe1 alloy powder catalyst.

[0079] Weigh 0.3g of Ag3Fe1 nano-alloy powder and 14.7g of ZrO2 synthesized in the above process, grind them thoroughly in an agate mortar for 20 min, and reduce them with hydrogen at 200℃ for 2 h with a hydrogen space velocity of 20000 h⁻¹. -1 A supported nano-Ag3Fe1 / ZrO2 alloy powder catalyst was prepared.

[0080] Table 1 Catalyst preparation conditions

[0081]

[0082]

[0083] Example 8: Synthesis of 2-Heptynic Acid Catalyzed by Ag3Fe1 / MCM-41

[0084] The structural formula of 2-heptaphylline is shown below:

[0085]

[0086] Under an anhydrous and oxygen-free argon atmosphere, 60 mg of catalyst Ag3Fe1 / MCM-41, cesium carbonate (3.0 mmol, 977 mg), 1-hexyne (2.0 mmol, 164 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was introduced, and the reaction was carried out at 25 °C for 24 h. After the reaction was completed, the reaction solution was transferred to a K2CO3 solution (2N, 10 mL), stirred at room temperature for 30 min, and the mixture was extracted with dichloromethane (3 × 5 mL). The aqueous layer was acidified with hydrochloric acid to pH 1, and then extracted with diethyl ether (3 × 5 mL). The organic layer was dried with anhydrous Na2SO4 for 12 h, filtered, and the solvent was removed by vacuum to obtain the target product 2-heptyneic acid in 89% yield.

[0087] Examples 9-14: Reusability of Ag3Fe1 / MCM-41

[0088] The catalyst separated in Example 8 can be reused after washing and drying with diethyl ether. The yields of the product after five uses were 89%, 87%, 88%, 87%, and 87%, respectively.

[0089] Example 15: Synthesis of 2-heptanyne butyl ester catalyzed by Ag3Fe1 / MCM-41

[0090] The structural formula of 2-heptaethylbutyrate is shown below:

[0091]

[0092] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag3Fe1 / MCM-41 (60 mg), potassium tert-butyl (6.0 mmol, 577 mg), 1-hexyne (2.0 mmol, 164 mg), iodobutane (2.2 mmol, 405 mg), and acetonitrile (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 25 °C for 24 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product, n-butylpropynate, with a separation yield of 94%.

[0093] Example 16: Synthesis of 2-Octynic Acid Catalyzed by Ag9Fe1 / ZSM-5

[0094] The structural formula of 2-octynoic acid is shown below:

[0095]

[0096] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag9Fe1 / ZSM-5 (60 mg), rubidium carbonate (1.0 mmol, 331 mg), 1-heptyne (2.0 mmol, 192 mg), and dimethyl sulfoxide (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was introduced, and the reaction was carried out at 30 °C for 16 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product 2-octynoic acid, with a separation yield of 91%.

[0097] Example 17: Synthesis of 2-nonyneic acid catalyzed by Ag7Fe1 / USY

[0098] The structural formula of 2-nonyneic acid is shown below:

[0099]

[0100] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag7Fe1 / USY (15 mg), lithium carbonate (3.0 mmol, 222 mg), 1-octyne (2.0 mmol, 220 mg), and tetrahydrofuran (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 35 °C for 16 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product 2-nonyneic acid, with a separation yield of 93%.

[0101] Example 18: Synthesis of 2-nonyneobutyl ester catalyzed by Ag5Fe1 / SiO2

[0102] The structural formula of 2-nonyne butyl ester is shown below:

[0103]

[0104] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag3Fe1 / MCM-41 (150 mg), sodium carbonate (3.0 mmol, 318 mg), 1-octyne (2.0 mmol, 220 mg), iodobutane (2.0 mmol, 368 mg), and dichloromethane (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 40 °C for 12 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product, butyl nonynate, with a separation yield of 74%.

[0105] Example 19: Synthesis of 4,4-dimethylpentyneic acid catalyzed by Ag1Fe1 / Ai2O3

[0106] The structural formula of 4,4-dimethylpentyneic acid is shown below:

[0107]

[0108] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag3Fe1 / MCM-41 (60 mg), cesium carbonate (3.0 mmol, 977 mg), 3,3-dimethyl-1-butyne (2.0 mmol, 167 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 25 °C for 30 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product 4,4-dimethylpentyneic acid, with a separation yield of 86%.

[0109] Example 20: Synthesis of 3-cyclopropylpropynic acid catalyzed by Ag3Fe1 / TiO2

[0110] The structural formula of 3-cyclopropylpropynic acid is shown below:

[0111] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag3Fe1 / MCM-41 (60 mg), cesium carbonate (3.0 mmol, 977 mg), cyclopropylacetylene (2.0 mmol, 133 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 25 °C for 48 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product 3-cyclopropylpropynic acid, with a separation yield of 90%.

[0112]

[0113] Example 21: Synthesis of 3-cyanobenzyl-3-cyclopropylpropynate ester catalyzed by Ag3Fe1 / ZrO2

[0114] The structural formula of 3-cyclopropylpropynic acid is shown below:

[0115]

[0116] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag3Fe1 / MCM-41 (60 mg), cesium carbonate (3.0 mmol, 977 mg), cyclopropaneacetylene (2.0 mmol, 132 mg), 3-cyanobenzyl bromide (2.6 mmol, 510 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was introduced, and the reaction was carried out at 25 °C for 16 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product 3-cyclopropylpropynic acid, with a separation yield of 75%.

[0117] Example 22: Synthesis of 3-cyanobenzyl-4-methyl-2-propynate catalyzed by Ag3Fe1 / MCM-41.

[0118]

[0119] Under an anhydrous and oxygen-free argon atmosphere, catalyst Ag3Fe1 / MCM-41 (60 mg), cesium carbonate (3.0 mmol, 977 mg), 3-methylbutyne (2.0 mmol, 136 mg), 3-cyanobenzyl bromide (3.0 mmol, 666 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was introduced, and the reaction was carried out at 25°C for 16 hours. After the reaction was completed, 15 mL of purified water was added to the reaction solution, the catalyst was filtered off, and then extracted with diethyl ether. The organic phase was washed with saturated sodium chloride aqueous solution, dried with anhydrous magnesium sulfate for 12 hours, and finally filtered and separated. The solution was concentrated under vacuum to obtain the target product 3-cyclopropylpropynic acid, with a separation yield of 65%. Comparative Example 1: Reaction of 1-hexyne with CO2 without catalyst participation.

[0120] In an anhydrous and oxygen-free argon atmosphere, cesium carbonate (3.0 mmol, 977 mg), 1-hexyne (2.0 mmol, 164 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 25 °C for 16 hours. After the reaction was completed, the reaction solution was transferred to a K2CO3 solution (2 N, 10 mL), stirred at room temperature for 30 min, and the mixture was extracted with dichloromethane (3 × 5 mL). The aqueous layer was acidified with hydrochloric acid to pH 1, and then extracted with diethyl ether (3 × 5 mL). The organic layer was dried with anhydrous Na2SO4 for 12 hours, filtered, and the solvent was removed by vacuum to obtain the target product, 2-heptyneic acid, with a separation yield of 15%.

[0121] Comparative Example 2: Reaction of 1-hexyne and CO2 catalyzed by MCM-41 molecular sieve

[0122] Under an anhydrous and oxygen-free argon atmosphere, MCM-41 (60 mg), cesium carbonate (3.0 mmol, 977 mg), 1-hexyne (2.0 mmol, 164 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 25 °C for 16 hours. After the reaction was completed, the reaction solution was transferred to a K2CO3 solution (2 N, 10 mL), stirred at room temperature for 30 min, and the mixture was extracted with dichloromethane (3 × 5 mL). The aqueous layer was acidified with hydrochloric acid to pH = 1, and then extracted with diethyl ether (3 × 5 mL). The organic layer was dried with anhydrous Na2SO4 for 12 hours, filtered, and the solvent was removed by vacuum to obtain the target product, 2-heptyneic acid, with a separation yield of 18%.

[0123] Comparative Example 3: Reaction of 1-hexyne and CO2 catalyzed by Ag-Fe nanoalloys

[0124] Under an anhydrous and oxygen-free argon atmosphere, Ag3Fe1 (60 mg), cesium carbonate (3.0 mmol, 977 mg), 1-hexyne (2.0 mmol, 164 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was introduced, and the reaction was carried out at 25 °C for 16 hours. After the reaction, the reaction solution was transferred to a K2CO3 solution (2 N, 10 mL), stirred at room temperature for 30 min, and the mixture was extracted with dichloromethane (3 × 5 mL). The aqueous layer was acidified with hydrochloric acid to pH = 1, and then extracted with diethyl ether (3 × 5 mL). The organic layer was dried with anhydrous Na2SO4 for 12 hours, filtered, and the solvent was removed by vacuum to obtain the target product 2-heptyneic acid, with a separation yield of 63%. Comparative Example 4: The reaction of 1-hexyne with CO2 with increased Ag-Fe nano-alloy catalyst was compared.

[0125] In an anhydrous and oxygen-free argon atmosphere, Ag3Fe1 (120 mg), cesium carbonate (3.0 mmol, 977 mg), 1-hexyne (2.0 mmol, 164 mg), and DMF (15 mL) were added to a 50 mL Schlenk flask. CO2 (1 atm) was then introduced, and the reaction was carried out at 25 °C for 16 hours. After the reaction was completed, the reaction solution was transferred to a K2CO3 solution (2 N, 10 mL), stirred at room temperature for 30 min, and the mixture was extracted with dichloromethane (3 × 5 mL). The aqueous layer was acidified with hydrochloric acid to pH 1, and then extracted with diethyl ether (3 × 5 mL). The organic layer was dried with anhydrous Na2SO4 for 12 hours, filtered, and the solvent was removed by vacuum to obtain the target product, 2-heptyneic acid, with a separation yield of 85%.

[0126] The separated catalyst can be reused after washing and drying with diethyl ether. The yields of the five products were 85%, 83%, 80%, 65%, and 53%, respectively.

[0127] The above embodiments demonstrate that the method for preparing alkyl alkynyl acids or alkyl alkynyl esters according to the present invention, using a supported nano-Ag-Fe alloy as a catalyst, converts CO2 into high-value-added chemicals. This reaction can be carried out under normal temperature and pressure conditions, with mild reaction conditions, high product yield, and good substrate versatility. The supported catalyst is easily recovered and reused during the reaction, and the reaction process is simple and easy to operate, providing a new process route for the high-value utilization of carbon dioxide.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synthesizing alkyl alkynic acids or alkyl alkynic esters, characterized in that, Preparation of alkyl acetylenic acid or alkyl acetylenic acid ester by taking aliphatic terminal alkyne compound and carbon dioxide as raw materials; the catalyst used is Ag x Fe y / support, x, y are molar compositions of silver, iron; the molar ratio of silver to iron of the catalyst is 9:1~1:1; The support is SiO2 and / or molecular sieve, and the molecular sieve is one or more of MCM-41, ZSM-5, and USY. Ag in the catalyst x Fe y The loading capacity is 1–55 wt%.

2. The synthesis method according to claim 1, characterized in that, The molecular sieve is MCM-41.

3. The synthesis method according to claim 1, characterized in that, The silver to iron molar ratio of the catalyst is 5:1 to 1:

1.

4. The synthesis method according to claim 1, characterized in that, Ag in the catalyst x Fe y The loading capacity is 1 to 30 wt%.

5. The synthesis method according to claim 4, characterized in that, Ag in the catalyst x Fe y The loading capacity is 5-20 wt%.

6. The synthesis method according to claim 1, characterized in that, The preparation method of the catalyst includes the following steps: [The steps are described in the original text, but are not translated here.] x Fe y Nano-alloys and supports were prepared into powders, which were then reduced under a hydrogen atmosphere to obtain supported nano-Ag-Fe alloy powder catalysts. In the reduction step, the hydrogen space velocity is 1000~40000 h⁻¹. -1 The reduction temperature is 50~300℃, and the reduction time is 1~10h.

7. The synthesis method according to claim 6, characterized in that, The Ag x Fe y The preparation method of nano-alloys includes: preparing a mixture of silver salt, iron salt, organic base, organic solvent, and anhydrous sodium sulfate, and calcining the mixture; The roasting temperature is 200~500℃, and the roasting time is 0.5 h~5 h.

8. The synthesis method according to claim 7, characterized in that, To ensure that the silver and iron salts are completely dissolved in the mixture.

9. The synthesis method according to claim 7, characterized in that, The calcined powder was filtered in a hydrazine hydrate solution.

10. The synthesis method according to claim 9, characterized in that, The concentration range of the hydrazine hydrate solution is 0.01~0.5 mol / L.

11. The synthesis method according to claim 10, characterized in that, The filtered powder is then dried.

12. The synthesis method according to claim 11, characterized in that, The drying temperature is 50~100℃, and the drying time is 2~24 h.

13. The synthesis method according to claim 7, characterized in that, The organic solvent is one or more of benzene, toluene, xylene, chlorobenzene, dichlorobenzene, dichloromethane, methanol, ethanol, isopropanol, acetonitrile, pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; The organic base is one or more of the following: methylamine, urea, ethylamine, ethanolamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, 1,3-propanediamine, 1,2-propanediamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, benzylamine, cyclohexylamine, o-toluidine, m-toluidine, p-toluidine, diphenylamine, n-hexylamine, and benzidine. The silver salts and iron salts mentioned are various inorganic metal salts and organic metal salts.

14. The synthesis method according to claim 13, characterized in that, The organic solvent is xylene; the organic base is n-hexylamine.

15. The synthesis method according to claim 1, characterized in that, The chemical formula of the aliphatic terminal alkyne compound is shown in formula (Ⅰ): ； R1 is selected from C4~C12 alkyl and cycloalkyl groups.

16. The synthesis method according to claim 1, characterized in that, The reaction was carried out at room temperature and pressure.

17. The synthesis method according to claim 1, characterized in that, The reaction temperature is 20~40℃, and the reaction time is 12~48 h.

18. The synthesis method according to claim 17, characterized in that, The reaction temperature is 25~30℃, and the reaction time is 12~24h.

19. The synthesis method according to claim 1, characterized in that, In an anhydrous and oxygen-free environment, an aliphatic terminal alkyne compound and a base are mixed in an organic solvent, and carbon dioxide is introduced to react under the action of a catalyst to obtain an alkyl alkyne acid compound; the base is an inorganic base.

20. The synthesis method according to claim 19, characterized in that, The inorganic base is one or more of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, tert-butylpotassium, and tert-butylsodium. The organic solvent is one of dichloromethane, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and dimethyl sulfoxide; The amount of catalyst used in the liquid-phase reaction system is 1–10 g / L; The molar equivalent ratio of the base to the aliphatic terminal alkyne compound is 0.5 to 3.

0.

21. The synthesis method according to claim 20, characterized in that, The inorganic base is cesium carbonate and / or potassium tert-butyl; The organic solvent is N,N-dimethylformamide; The catalyst dosage is 2–5 g / L; The molar equivalent ratio of the base to the aliphatic terminal alkyne compound is 1 to 2.

0.

22. The synthesis method according to any one of claims 1-21, characterized in that, The reactants also include a haloalkanes R2X; X is one of F, Cl, Br, and I; R2 is selected from C4-C12 alkyl and cycloalkyl groups.

23. The synthesis method according to claim 22, characterized in that, X is Br and I; the molar ratio of aliphatic terminal alkynes to haloalkanes is 1:1 to 1.

7.

24. The synthesis method according to claim 23, characterized in that, The molar ratio of the aliphatic terminal alkyne compound to the haloalkanes is 1:1 to 1.5.

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