A gold cluster catalyst, its preparation method and use

Abstract

The application discloses a gold group cluster catalyst, a preparation method thereof and application of the gold group cluster catalyst in catalyzing a carbon dioxide hydroformylation reaction. The gold group cluster catalyst is prepared by a size aggregation method, and is composed of a core gold and a peripheral iron-containing organic phosphine ligand. The catalyst has performance between homogeneous mononuclear metal complex and heterogeneous particle catalyst, and has advantages of homogeneous catalyst and heterogeneous catalyst. The preparation method comprises the following steps: gold and iron two metal precursors are fully mixed and coordinated in a specific solvent, then a quantitative fresh sodium borohydride solution is added, and the solid crude product is obtained through evaporation, extraction and separation, and finally the catalyst is obtained through thin layer chromatography separation. The whole preparation process has the characteristics of mild conditions, simple process, green environmental protection, considerable catalyst yield, precise structure, high purity, high repeatability and high stability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalytic science, and particularly relates to a gold-based cluster catalyst, a preparation method thereof and application thereof in catalyzing a carbon dioxide hydroformylation reaction. BACKGROUND

[0002] The resource utilization and sequestration of carbon dioxide (CO2) is one of the important technical paths to achieve the green development strategy goal of "carbon peak and carbon neutralization" of the country. Among them, taking CO2 as a carbon resource, efficiently converting it into high-value-added energy or chemicals can not only achieve emission reduction, but also turn waste into treasure and recycle, reducing the consumption of fossil energy. Therefore, the resource utilization of CO2 has obvious technical and economic advantages. At present, CO2 emissions in China are mainly concentrated in the fields of thermal power generation, steel, cement, chemical industry, etc., and the emission sources are widely distributed and mainly in low concentration. Therefore, in most industrial practices, CO2 capture and transportation are the premise or indispensable link to realize its resource utilization and sequestration, which greatly increases the cost of CO2 conversion and utilization, and limits the large-scale utilization of CO2. Therefore, breaking through the CO2 capture and conversion coupling technology to realize the integration of capture-conversion has extremely important research and practical application value.

[0003] The CO2 molecule has a stable structure and is chemically inert, with a very high chemical conversion energy barrier, so efficient, high selectivity, low cost and green catalytic conversion and utilization are extremely challenging. The key to CO2 catalytic conversion and utilization is to build a new catalytic reaction system, and the core is to develop a catalyst with high performance and low cost. Among the many CO2 catalytic conversion routes, the hydroformylation reaction has significant potential advantages. Compared with the traditional hydrogenation route, the CO2 hydroformylation reaction has milder reaction conditions (100-150℃), and can produce a variety of important fine chemicals. Traditional CO2 hydroformylation reactions mainly use Ru, Ir and other noble metals as active components of homogeneous catalysts, which exhibit good catalytic performance, but the cost is high, and the catalyst is difficult to separate and recover, which seriously restricts its industrial application. Therefore, developing new catalysts and catalytic systems with excellent performance, low cost and recyclability has very important practical significance for the application of CO2 hydroformylation reaction. SUMMARY

[0004] The purpose of the present application is to provide a gold-based cluster catalyst prepared using a size aggregation method and a preparation method and catalytic application thereof.

[0005] In order to achieve the above-mentioned purpose, the following technical scheme is adopted in the present application: a gold-based cluster catalyst with accurate and stable structure, which comprises a core gold and a peripheral iron-containing organophosphorus ligand.

[0006] Further, the iron-containing organophosphorus ligand is 1,1'-bis(diphenylphosphino) ferrocene.

[0007] A preparation method of the gold-based cluster catalyst with the above structure, which is accurate and stable, comprises the following steps:

[0008] (1) gold precursor is added into an organic solvent and stirred thoroughly, and then an iron-containing organic phosphine ligand is weighed and added into the above suspension, and stirred thoroughly to make it fully mixed and reacted;

[0009] (2) a sodium borohydride solution is prepared and added dropwise into the solution prepared in step (2), and then the stirring is continued for 2-12 hours;

[0010] (3) the mixed solution reacted in step (2) is evaporated and concentrated into a viscous liquid, and then an extractant is added, and the solution is left to stand until the orange-red solid is completely precipitated, and then the solid is centrifuged and washed with n-hexane for 2-3 times;

[0011] (4) the solid prepared in step (3) is dissolved in dichloromethane, a mixed solution of methanol and DMC is prepared, and then thin layer chromatography is used to purify the dissolved solid, so that the gold-based cluster catalyst with high purity is obtained.

[0012] Further, the gold precursor is chloroauric acid or triphenylphosphine gold chloride, and the molar number of gold is 0.1-10 mmol; the molar ratio of the gold precursor to the iron-containing organic phosphine ligand is 1:0.1-1.2.

[0013] Further, the organic solvent in step (1) is methanol, ethanol, acetonitrile, dichloromethane, toluene, acetone, tetrahydrofuran, isopropanol or n-butanol, and the added amount of the organic solvent is 5-500 mL.

[0014] Further, the solvent of the sodium borohydride solution in step (2) is water, methanol, ethanol, acetonitrile, dichloromethane, toluene, acetone, tetrahydrofuran, isopropanol or n-butanol, and the concentration is 0.1-1 mol / L.

[0015] Further, the extractant in step (3) is n-pentane, n-hexane or cyclohexane, and the added amount is 10 times the volume of the organic solvent in step (1).

[0016] Further, the volume ratio of methanol to DMC in the mixed solution in step (4) is 1 / 30, 1 / 15, 1 / 10, 1 / 6, 1 / 3 or 1 / 2.

[0017] Further, the separation liquid of the thin layer chromatography in step (4) is methanol, ethanol, n-butanol, isopropanol, DMC or dichloroethane.

[0018] The application of the gold-based cluster catalyst with the above structure, which is accurate and stable, the catalyst is used in the carbon dioxide hydroformylation reaction, and the specific application steps are as follows:

[0019] (1) At room temperature, the carbon dioxide in the air or industrial waste gas is selectively absorbed by the secondary amine substrate, and the carbon dioxide is separated from the waste gas in the form of ammonium carbamate salt to complete the capture;

[0020] (2) Hydrogen is filled into the catalytic reactor loaded with the gold group cluster catalyst, the reaction pressure is 1-12 MPa, the reaction temperature is 50-120 DEG C, and the ammonium carbamate salt is simultaneously introduced to start the catalytic reaction;

[0021] (3) After the reaction is completed, a small amount of water is added into the catalytic reactor, and the catalyst is separated by centrifugation and used for recycling.

[0022] The secondary amine substrate includes, but is not limited to, pyrrolidine, piperidine, morpholine, dimethylamine and diethylamine. The substrate dosage is 1-50 mmol, the catalyst dosage is 0.05-1 mol% (based on the total amount of the substrate in the form of secondary amine), the reaction pressure is 1-12 MPa, the reaction temperature is 50-120 DEG C, the reaction time is 2-24 h, and the H2 / CO2 volume ratio is 4-0.5 / 1. The catalytic reaction can be carried out under the condition of no solvent or by adding a reaction solvent. The reaction solvent includes, but is not limited to, acetonitrile, ethanol and methanol.

[0023] The application provides a gold group cluster catalyst prepared by a size aggregation method, which is composed of a gold inner core and a peripheral iron-containing organic phosphine ligand, has a performance between a homogeneous mononuclear metal complex and a heterogeneous particulate catalyst, and has the advantages of homogeneous and heterogeneous catalysts. The preparation method comprises the following steps: gold and iron two metal precursors are fully mixed and coordinated in a specific solvent, then a quantitative fresh sodium borohydride solution is added, and the solid crude product is obtained through evaporation, extraction and separation, and finally the catalyst is obtained through thin layer chromatography separation. The whole preparation process has mild conditions, simple flow, and is green and environmentally friendly, the obtained catalyst has the characteristics of considerable yield, precise structure, high purity, high repeatability and high stability.

[0024] The catalyst can be coupled, captured and utilized in the carbon dioxide hydroformylation reaction, realizes the in-situ chemical conversion and utilization of CO2, greatly simplifies the CO2 utilization process, and has excellent catalytic performance. Under the conditions of a reaction temperature of 110 DEG C and a reaction pressure of 8 MPa, the conversion rate of the secondary amine substrate is greater than 95%, and the selectivity of the target product is close to 100%. Meanwhile, the catalyst regeneration process is simple, environmentally friendly and does not need additional substances, and the catalyst has the ability of multiple recycling, so the catalyst has great industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a distribution diagram of a thin layer chromatography separation strip of the crude product prepared in Example 1.

[0026] Figure 2 It is a UV-Vis spectrum diagram of the catalyst prepared in Example 1.

[0027] Figure 3 is the UV-Vis spectrum of the catalyst prepared in Example 1 after regeneration.

[0028] Figure 4 is the catalytic performance graph of the catalyst prepared in Example 1.

[0029] Figure 5 is the catalytic cycle result graph of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0030] In order to better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0032] Example 1

[0033] Gold cluster catalyst: 50 mg of chloroauric acid triphenylphosphine was added to 5 ml of ethanol solution, and stirred vigorously at room temperature for 30 minutes or ultrasonically treated for 5 minutes to obtain a uniformly dispersed white emulsion solution; 28 mg of 1,1'-bis(diphenylphosphino)ferrocene was added to the reaction solution, and stirring was continued for 30 minutes to obtain a light yellow reaction solution. 10 mg of NaBH4 was weighed and dissolved in 2 ml of ethanol, and then slowly added dropwise into the reaction flask. The reaction solution quickly turned into a black solution, and after 8 hours of continuous reaction, the reaction mixture turned into a deep red color, and the reaction was stopped. The reaction solution was centrifuged to remove solid impurities, and then concentrated to 0.5 ml using a rotary evaporator, and then 100 ml of n-pentane was added to the concentrated solution, mixed thoroughly, and then allowed to stand until the brick red solid completely precipitated. High-speed centrifugation was performed to remove the upper clear liquid, and the lower solid was washed with n-hexane solution for 2-3 times to obtain the crude product. A mixture of methanol and dichloromethane (methanol:dichloromethane = 1:6) was prepared as a separation solution, the crude product was dissolved in 1 ml of dichloromethane, and then dropped onto a thin layer chromatography plate, and allowed to stand for separation. Different bands appeared, and the orange-red wide band located in the upper layer was the product (Au25(PPh3)18). Figure 1). The product band was scraped off and dissolved in ethanol solution, and evaporated using a rotary evaporator to obtain the target product. The product was determined to be a gold cluster consisting of eight gold atoms in the core and four 1,1'-bis(diphenylphosphino)ferrocene ligands on the periphery by UV-Vis spectroscopy (UV-Vis). Figure 1 and 2 ).

[0034] CO2 capture and utilization: 2 mmol of pyrrolidine was added to a 50 mL slurry bed catalytic reactor, and pressurized to 0.5 MPa with industrial waste gas (~10% CO2) for 3 minutes, and the gas was released. The reaction substrate was completely converted into ammonium carbamate salt by repeated pressurization for 4-5 times. Subsequently, 5 mL of acetonitrile and 0.1 mol% of the catalyst were added to the reactor, and 6 MPa of hydrogen was charged. The stirring was started, and the temperature was raised to 90°C, and the reaction was carried out for 12 hours. Then, 2 mL of water was added to the reaction solution, and high-speed centrifugation was performed to realize the recycling of the catalyst, and the catalyst maintained structural stability Figure 3 ). The conversion rate was greater than 90%, and the selectivity of the formyl product was close to 100% Figure 4 ), and multiple cycles were achieved Figure 5 ).

[0035] Example 2

[0036] Gold cluster catalyst: 80 mg of triphenylphosphine gold chloride was added to 8 mL of ethanol solution, and stirred vigorously at room temperature for 30 minutes to obtain a uniformly dispersed white emulsion. 45 mg of 1,1'-bis(diphenylphosphino)ferrocene was added to the reaction solution, and continued to stir for 30 minutes to obtain a light yellow reaction solution. 18 mg of NaBH4 was weighed and dissolved in 2 mL of ethanol, and then slowly added to the reaction flask. The reaction solution quickly turned into a black solution, and after 8 hours of continuous reaction, the reaction mixture turned into a deep red color, and the reaction was stopped. The reaction solution was centrifuged to remove the solid impurities, and then concentrated to 0.5 mL using a rotary evaporator. 100 mL of n-pentane was added to the concentrated solution, mixed thoroughly, and then left to stand until the brick red solid completely precipitated. High-speed centrifugation was performed to remove the upper clear liquid, and the lower solid was washed 2-3 times with n-hexane solution to obtain the crude product. A mixture of methanol and dichloromethane (methanol:dichloromethane = 1:10) was prepared as a separation liquid, the crude product was dissolved in 1 mL of dichloromethane, and then dropped onto a thin layer chromatography plate, and left to stand for separation. Different bands appeared, and the orange-red wide band on the upper layer was the product. The product band was scraped off and dissolved in ethanol solution, and evaporated using a rotary evaporator to obtain the target catalyst.

[0037] CO2 capture and utilization: 2 mmol of piperidine was added into a 50 mL slurry-bed catalytic reactor, and pressurized to 0.5 MPa with industrial waste gas (-10% CO2) for 3 min, and then released. The pressurization and release were repeated 4-5 times to convert the substrate to ammonium carbamate salt completely. Then 5 mL of acetonitrile and 0.1 mol% of catalyst were added into the reactor, and pressurized to 6 MPa with hydrogen. The stirring was started, and the temperature was raised to 110 °C, and the reaction was carried out for 12 h. Then 2 mL of water was added into the reaction solution, and centrifuged at high speed to recover the catalyst, and the catalyst maintained the structural stability. The conversion was more than 80%, and the selectivity of formyl product was close to 100%.

[0038] Example 3

[0039] Gold cluster catalyst: 80 mg of chloro(triphenylphosphine)gold was added into 10 mL of acetonitrile solution, and stirred at room temperature for 30 min to obtain a uniform dispersion solution; 45 mg of 1,1'-bis(diphenylphosphino)ferrocene was added into the reaction solution, and stirred for another 30 min to obtain a light yellow reaction solution. 18 mg of NaBH4 was weighed and dissolved in 2 mL of water, and then quickly added into the reaction flask. The reaction solution turned into a black solution quickly, and the reaction mixture turned into a deep red color after 8 h of continuous reaction. The reaction was stopped. The reaction solution was centrifuged to remove the solid impurities, and then concentrated to 0.5 mL using a rotary evaporator. 100 mL of n-pentane was added into the concentrated solution, and mixed thoroughly, and then left to stand until the brick red solid was completely precipitated. The upper clear solution was removed by high-speed centrifugation, and the lower solid was washed with n-hexane solution for 2-3 times to obtain the crude product. A mixture of methanol and dichloromethane (methanol:dichloromethane = 1:6) was prepared as a separation solution, and the crude product was dissolved in 1 mL of dichloromethane, and then dropped and coated on a thin layer chromatography plate. The separation was carried out by standing, and different bands appeared, in which the orange-red wide band located in the upper layer was the product. The product band was scraped off, dissolved in ethanol solution, and evaporated using a rotary evaporator to obtain the target catalyst.

[0040] CO2 capture and utilization: 2 mmol of piperidine was added into a 50 mL slurry-bed catalytic reactor, and pressurized to 0.5 MPa with industrial waste gas (-10% CO2) for 3 min, and then released. The pressurization and release were repeated 4-5 times to convert the substrate to ammonium carbamate salt completely. Then 5 mL of acetonitrile and 0.1 mol% of catalyst were added into the reactor, and pressurized to 6 MPa with hydrogen. The stirring was started, and the temperature was raised to 110 °C, and the reaction was carried out for 12 h. Then 2 mL of water was added into the reaction solution, and centrifuged at high speed to recover the catalyst, and the catalyst maintained the structural stability. The conversion was more than 80%, and the selectivity of formyl product was close to 100%.

[0041] Example 4

[0042] Gold cluster catalyst: 50 mg of chloroauric acid triphenylphosphine was added into 8 ml of acetonitrile solution, and stirred vigorously for 30 minutes at room temperature to obtain a uniformly dispersed solution; 28 mg of 1,1'-bis(diphenylphosphino)ferrocene was added into the reaction solution, and continued to stir to obtain a light yellow reaction solution. 10 mg of NaBH4 was weighed and dissolved in 2 ml of water, and then quickly added into the reaction solution, and the reaction was continued for 8 hours. The reaction mixture turned into a deep red color, and the reaction was stopped. The reaction solution was centrifuged to remove solid impurities, and then concentrated to 0.5 ml using a rotary evaporator. 100 ml of n-pentane was added into the concentrated solution, and mixed thoroughly, and then left to stand until the brick red solid was completely precipitated. High-speed centrifugation was performed to remove the upper clear liquid, and the lower solid was washed with n-hexane solution for 2-3 times to obtain the crude product. A mixture of methanol and dichloromethane (methanol:dichloromethane = 1:10) was prepared as a separation liquid, and the crude product was dissolved in 1 ml of dichloromethane and dropped onto a thin layer chromatography plate, and then left to stand for separation. Different bands appeared, and the orange-red wide band located in the upper layer was the product. The product band was scraped off, dissolved in an ethanol solution, and then evaporated using a rotary evaporator to obtain the target catalyst.

[0043] Capture and utilization of CO2: 2 mmol of diethylamine was added into a 50 ml slurry bed reactor, and pressurized to 0.5 MPa using industrial waste gas (about 10% CO2) for 3 minutes, and then the gas was released. The reaction substrate was completely converted into ammonium carbamate salt by repeating the pressurization and release for 4-5 times. Then 5 ml of ethanol and 0.1 mol% of catalyst were added into the reactor, and 6 MPa of hydrogen gas was filled. The stirring was started, and the temperature was heated to 80°C, and the reaction was continued for 12 hours. Then 2 ml of water was added into the reaction solution, and high-speed centrifugation was performed to realize the recycling of the catalyst, and the catalyst maintained the structural stability. The reaction conversion rate was greater than 50%, and the selectivity of the formyl product was close to 100%.

[0044] Example 5

[0045] Gold cluster catalyst: 800 mg of chloroauric acid triphenylphosphine was added into 100 ml of ethanol solution, and stirred vigorously at room temperature for 30 minutes; 442 mg of 1,1'-bis(diphenylphosphino)ferrocene was added into the flask, and continued to stir to obtain a light yellow reaction solution. 180 mg of NaBH4 was weighed and dissolved in 15 ml of ethanol, and slowly added into the reaction solution, and continued to stir for 10 hours. The reaction mixture turned into a deep red color, and the reaction was stopped. The reaction solution was centrifuged to remove solid impurities, and then concentrated to 10 ml using a rotary evaporator. 800 ml of n-pentane was added into the concentrated solution, and mixed thoroughly, and then left to stand until the brick red solid was completely precipitated. High-speed centrifugation was performed to remove the upper clear liquid, and the lower solid was washed with n-hexane solution for 2-3 times to obtain the crude product. A mixture of methanol and dichloromethane (methanol:dichloromethane = 1:6) was prepared as a separation solution, and the crude product was dissolved in 15 ml of dichloromethane, and then dropped onto a thin layer chromatography plate, and left to stand for separation. Different bands appeared, and the orange-red wide band located in the upper layer was the product. The product band was scraped off, dissolved in an ethanol solution, and evaporated using a rotary evaporator to obtain the target catalyst.

[0046] CO2 capture and utilization: 30 mmol of pyrrolidine was added into a 50 ml slurry bed catalytic reactor, and pressurized to 0.8 MPa using industrial waste gas (about 10% CO2) for 3 minutes, and then released the gas. The gas was repeatedly charged and released to completely convert the reaction substrate into the corresponding ammonium carbamate salt. After the CO2 capture was completed, 0.1 mol% of the catalyst was added into the reactor, and then 7 MPa of hydrogen was charged. The stirring was started, and heated to 110 degrees Celsius, and reacted for 15 hours. Then 15 ml of water was added into the reaction solution, and high-speed centrifugation was performed to realize the recycling of the catalyst. The reaction conversion rate was greater than 85%, and the formyl product selectivity was 100%.

[0047] Example 6

[0048] Gold cluster catalyst: 500 mg of chloroauric acid triphenylphosphine was added into 80 ml of acetonitrile solution, and stirred vigorously at room temperature for 30 minutes; 280 mg of 1,1'-bis(diphenylphosphino)ferrocene was added into the flask, and continued to stir to obtain a light yellow reaction solution. 100 mg of NaBH4 was weighed and dissolved in 10 ml of water, and then quickly added into the reaction solution, and the reaction was continued to stir for 10 hours. The reaction mixture turned into a deep red color, and the reaction was stopped. The reaction solution was centrifuged to remove the solid impurities, and then concentrated to 8 ml by a rotary evaporator. 600 ml of n-pentane was added into the concentrated solution, and mixed thoroughly, and then left to stand until the brick red solid was completely precipitated. High-speed centrifugation was performed to remove the upper clear liquid, and the lower solid was washed with n-hexane solution for 2-3 times to obtain the crude product. A mixture of methanol and dichloromethane (methanol:dichloromethane = 1:6) was prepared as a separation liquid, and the crude product was dissolved in 12 ml of dichloromethane, and then dropped onto a thin layer chromatography plate, and left to stand for separation. Different bands appeared, and the orange-red wide band located in the upper layer was the product. The product band was scraped off, dissolved in ethanol solution, and then evaporated by a rotary evaporator to obtain the target catalyst.

[0049] CO2 capture and utilization: 30 mmol of piperidine was added into a 50 ml slurry bed catalytic reactor, and pressurized to 0.8 MPa with industrial waste gas (about 10% CO2) for 3 minutes, and then released the gas. The gas was repeatedly charged and released to completely convert the reaction substrate into the corresponding ammonium carbamate salt. After the CO2 capture was completed, 0.1 mol% of the catalyst was added into the reactor, and then 7 MPa of hydrogen was charged. The stirring was started, and heated to 110 degrees Celsius, and then reacted for 15 hours. Then 15 ml of water was added into the reaction solution, and high-speed centrifugation was performed to realize the recycling of the catalyst. The reaction conversion rate was greater than 75%, and the formyl product selectivity was 100%.

[0050] Example 7

[0051] Gold cluster catalyst: 1 gram of chloroauric acid triphenylphosphine was added into 100 milliliter acetonitrile solution, and stirred vigorously for 30 minutes at room temperature. 560 milligrams of 1,1'-bis(diphenylphosphino)ferrocene was added into the flask, and the solution was stirred to get a light yellow solution. 200 milligrams of NaBH4 was dissolved in 20 milliliter water, and added into the solution quickly. The solution was stirred for 10 hours, and the reaction mixture was changed to deep red. The reaction was stopped. The reaction mixture was centrifuged to remove the solid impurities, and concentrated to 15 milliliter by rotary evaporator. 1.2 liter of n-pentane was added into the solution, and mixed well. The solution was left to stand until the brick red solid was completely precipitated. The solution was centrifuged at high speed, and the supernatant was removed. The solid was washed with n-hexane for 2-3 times to get the crude product. The crude product was dissolved in 24 milliliter dichloromethane, and dropped onto the thin layer chromatography. The product was separated by standing, and the orange-red wide band in the upper layer was the product. The product band was scraped, dissolved in ethanol, and evaporated by rotary evaporator to get the target catalyst.

[0052] CO2 capture and utilization: 60 millimoles of pyrrolidine was added into 100 milliliter slurry bed catalytic reactor, and pressurized to 1 megapascal with industrial waste gas (about 10% CO2) for 3 minutes, and released the gas. The gas was repeatedly charged and released to convert the reaction substrate to the corresponding carbamic acid ammonium salt completely. After the CO2 capture, 0.2 mol% of the catalyst was added into the reactor, and 7 megapascal of hydrogen was charged. The stirring was started, and the temperature was heated to 110 degrees Celsius. The reaction was carried out for 15 hours. Then, 30 milliliter of water was added into the reaction solution, and the catalyst was recovered by high speed centrifugation. The reaction conversion rate was greater than 90%, and the formyl product selectivity was 100%.

[0053] Example 8

[0054] Gold cluster catalyst: 10 grams of triphenylphosphine gold chloride was added into 1 liter of acetonitrile solution, and stirred vigorously at room temperature for 30 minutes; 5.6 grams of 1,1'-bis(diphenylphosphino) ferrocene was added into the flask, and continued to stir to obtain a light yellow reaction solution. 2 grams of NaBH4 was weighed and dissolved in 0.2 liters of water, and quickly added into the reaction solution, and continued to stir for 10 hours. The reaction mixture turned into a deep red color, and the reaction was stopped. The reaction solution was centrifuged to remove solid impurities, and then concentrated to 100 milliliters using a rotary evaporator. 12 liters of n-pentane was added into the concentrated solution, and mixed thoroughly, and then left to stand until the brick red solid completely precipitated. High-speed centrifugation was performed to remove the upper clear liquid, and the lower solid was washed 2-3 times with n-hexane solution to obtain a crude product. A mixture of methanol and dichloromethane (methanol:dichloromethane = 1:6) was prepared as a separation solution, and the crude product was dissolved in 0.25 liters of dichloromethane, and then dropped onto a thin layer chromatography plate, and left to stand to separate. Different bands appeared, and the orange-red wide band located in the upper layer was the product. The product band was scraped off, dissolved in an ethanol solution, and then evaporated using a rotary evaporator to obtain the target catalyst.

[0055] CO2 capture and utilization: 0.2 moles of pyrrolidine was added into a 0.5 liter slurry bed catalytic reactor, and pressurized to 1 megapascal using industrial waste gas (about 10% CO2) for 3 minutes, and then released the gas. The gas was repeatedly charged and released to completely convert the reaction substrate into the corresponding ammonium carbamate salt. After the CO2 capture was completed, 0.8 mol% of the catalyst was added into the reactor, and then 7 megapascal of hydrogen was charged. The stirring was started, and heated to 110 degrees Celsius, and reacted for 15 hours. Then 0.1 liters of water was added into the reaction solution, and high-speed centrifugation was performed to realize the recycling of the catalyst. The reaction conversion rate was greater than 90%, and the formyl product selectivity was 100%.

[0056] It should be understood that the present application is described by way of example only and modifications can be made within the scope and spirit of the application. The above detailed description of the preferred embodiments of the application. It should be understood that those skilled in the art without creative work can make many modifications and changes according to the concept of the present application on the basis of the prior art. Therefore, any technical solution obtained by logical analysis, reasoning or limited test by those skilled in the art on the basis of the prior art according to the concept of the present application shall be within the protection scope determined by the claims.

Claims

1. Use of a structurally precise and stable gold cluster catalyst comprising a gold core and a peripheral iron-containing organophosphine ligand; the iron-containing organophosphine ligand being 1,1'-bis(diphenylphosphino)ferrocene, characterised in that: The gold group cluster catalyst is composed of eight gold atoms in the core and four 1,1'-bis(diphenylphosphino) ferrocene ligands on the periphery, which is used in the carbon dioxide hydroformylation reaction, and the specific application steps are as follows: (1) At room temperature, the carbon dioxide in the air or industrial waste gas is selectively absorbed by the secondary amine substrate, and separated from the waste gas in the form of ammonium carbamate salt to complete the capture; (2) Hydrogen is filled into the catalytic reactor loaded with the gold group cluster catalyst, the reaction pressure is 1-12 MPa, the reaction temperature is 50-120 DEG C, and the ammonium carbamate salt is simultaneously introduced to start the catalytic reaction; (3) After the reaction is completed, a small amount of water is added into the catalytic reactor, and the catalyst is separated by centrifugation for recycling; The secondary amine substrate includes, but is not limited to, pyrrolidine, piperidine, morpholine, dimethylamine and diethylamine, the amount of the substrate in the form of secondary amine is 1-50 mmol, the amount of the catalyst is 0.05-1 mol%, the reaction pressure is 1-12 MPa, the reaction temperature is 50-120 DEG C, the reaction time is 2-24 h, and the H2 / CO2 volume ratio is 4-0.5 / 1.

Images