A graphene-based heterogeneous catalyst and a preparation method and application thereof

Abstract

The application provides a graphene-based heterogeneous catalyst and a preparation method and application thereof, and belongs to the technical field of catalyst preparation.The graphene-based catalyst comprises graphene, bisphosphite and a transition metal, and the bisphosphite is anchored on the graphene by a chemical bond.The catalyst provided by the application has high catalytic efficiency, long service life and is easy to separate.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and particularly relates to a graphene-based heterogeneous catalyst, its preparation method, and its application. Background Technology

[0002] The hydroformylation of olefins refers to the reaction of olefins with a mixture of carbon monoxide and hydrogen in the gas phase under certain temperature and pressure conditions, catalyzed by a catalyst, to produce an aldehyde with one more carbon atom than the starting olefin. This reaction is also known as "carbonyl synthesis." The hydroformylation of olefins is an important method for the industrial synthesis of aldehydes or alcohols. The aldehydes produced through this reaction can be further processed into alcohols, carboxylic acids, and esters, and are important raw materials for the production of detergents, fabric additives, plasticizers, and fragrances, possessing high commercial value.

[0003] Homogeneous catalysts possess advantages such as high catalytic activity, high selectivity, and mild reaction conditions, making them the primary catalytic system for hydroformylation reactions in industry, leading to the development of a series of homogeneous catalysts. However, in homogeneous catalytic systems, transition metal complex catalysts are readily soluble in both the product and the solvent, making product-catalyst separation difficult, especially in the hydroformylation of high-carbon olefins. To overcome these problems, employing heterogeneous catalytic systems for the hydroformylation of high-carbon olefins has practical value. However, currently, the more studied heterogeneous hydroformylation catalysis exhibits low selectivity and rapid loss of active catalyst components. Summary of the Invention

[0004] This invention provides a graphene-based heterogeneous catalyst, its preparation method, and its application. The catalyst has high catalytic efficiency, long lifetime, and is easy to separate.

[0005] To achieve the above objectives, the present invention provides a graphene-based heterogeneous catalyst, the catalyst comprising graphene, a bisphosphite, and a transition metal, wherein the bisphosphite is chemically anchored to the graphene; the structural formula of the bisphosphite anchored to the graphene is shown in Formula 1:

[0006]

[0007] Where X is a single bond, -O-, nitrogen-containing heterocycle, -S-, acyl or ester bond.

[0008] Preferably, X represents the L1 to L6 bonds as shown in the diagram:

[0009]

[0010] Preferably, the R1, R2, R3 and R4 groups are independently C1-C4 alkane groups, methoxy groups or hydrogen groups, respectively.

[0011] Preferably, the R1, R2, R3, and R4 groups are each one of M1 to M9; the M1 to M9 have the following structural formulas:

[0012]

[0013] Preferably, the graphene in the catalyst is hexagonal honeycomb with 1 to 10 layers; the amount of the transition metal added is 1 / 100 to 1 / 100000 of the total mass of graphene and bisphosphite.

[0014] The present invention also provides a method for preparing the graphene-based heterogeneous catalyst according to any one of the above claims, comprising the following steps:

[0015] 1) Organic functionalization of graphene yields functionalized graphene;

[0016] 2) Anchoring bisphosphites onto functionalized graphene to obtain bisphosphite-anchored graphene;

[0017] 3) The transition metal was reacted with graphene anchored by bisphosphite to obtain a graphene-based heterogeneous catalyst.

[0018] Preferably, the organic functionalization is achieved by reacting an organic compound with graphene to form a linking bond with the bisphosphite on the graphene; the organic compound preferably includes N-methylglycine, glycine, 1,2,4-pyrogallol, 3,4-dihydroxyphenylacetyl chloride, 4-chlorocatechol, and 3,4-dihydroxyphenylacetic acid.

[0019] Preferably, the anchoring in step 2) is performed using the following steps:

[0020] a. React a mixture of monophosphite and phosphorus trichloride to obtain a halomonophosphite;

[0021] b. Functionalized graphene was mixed with tetrahydrofuran containing triethylamine and sonicated to obtain a dispersion;

[0022] c. A toluene solution of a halomonophosphite is added dropwise to a dispersion to react and obtain a graphene-based heterogeneous catalyst.

[0023] Preferably, the method for preparing the monophosphite includes the following steps:

[0024] (1) Mix material A with toluene or xylene, add phosphorus trichloride, and react to obtain intermediate A; the structural formula of material A is shown in Formula 2; the structural formula of intermediate A is shown in Formula 3;

[0025] (2) Intermediate A and material B are mixed and reacted to obtain monophosphite; the structural formula of material B is shown in Formula 4:

[0026]

[0027] The present invention also provides the application of the graphene-based heterogeneous catalyst described in any of the above embodiments in the catalytic hydroformylation of high carbon olefins; wherein the high carbon olefins are C6 to C20 olefins.

[0028] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0029] In the graphene-based heterogeneous catalyst provided by this invention, graphene can alter the electron cloud distribution around the phosphite, improve the free energy during hydroformylation, thus favoring the hydroformylation reaction and enhancing its reactivity. The spatial structure of the bisphosphite ensures the proportion of linear aldehydes in the product. Furthermore, the bisphosphite is covalently anchored to graphene, improving its stability and extending the catalyst's lifespan.

[0030] Meanwhile, the graphene-based heterogeneous catalyst provided by this invention can be directly separated and recovered by filtration after the catalytic reaction is completed. The hydroformylation product is easy to separate from the catalyst, which reduces the separation cost. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides a graphene-based heterogeneous catalyst, comprising graphene, a bisphosphite, and a transition metal, wherein the bisphosphite is chemically anchored to the graphene; the structural formula of the bisphosphite anchored to the graphene is shown in Formula 1.

[0033]

[0034] Where X is a single bond, -O-, nitrogen-containing heterocycle, -S-, acyl or ester bond.

[0035] In this invention, X is preferably L1 to L6, and more preferably L1.

[0036] In this invention, the R1, R2, R3, and R4 groups are preferably independently C1-C4 alkane groups, methoxy groups, or hydrogen groups, and more preferably, the R1, R2, R3, and R4 groups are independently one of M1 to M9, with M1 being the most preferred; the M1 to M9 have the following structural formulas:

[0037]

[0038] In this invention, the graphene in the catalyst is preferably hexagonal honeycomb-shaped, with 1 to 10 layers, more preferably 2 to 5 layers; the amount of the transition metal added is preferably 1 / 100 to 1 / 100000 of the total mass of graphene and bisphosphite, more preferably 1 / 50 to 1 / 20. In this invention, the transition metal is preferably rhodium, cobalt, or iridium, more preferably rhodium or cobalt.

[0039] The graphene-based heterogeneous catalyst provided by this invention contains graphene. First, graphene can alter the electron cloud distribution around the phosphite, improving the free energy during hydroformylation and thus favoring the hydroformylation reaction, thereby increasing its reactivity. Second, the spatial structure of the bisphosphite ensures the proportion of linear aldehydes in the product. Third, the bisphosphite is covalently anchored to graphene, enhancing its stability and extending the catalyst's lifespan. Finally, anchoring the bisphosphite to graphene successfully heterogeneousizes the homogeneous catalyst, making the hydroformylation product easier to separate from the catalyst and reducing separation costs. Moreover, anchoring the bisphosphite to graphene in this invention is equivalent to organically modifying the graphene surface, improving its dispersibility and effectively preventing self-aggregation during storage and reaction; the combination of graphene and bisphosphite enhances the overall structural stability.

[0040] The present invention also provides a method for preparing the graphene-based heterogeneous catalyst according to any one of the above claims, comprising the following steps:

[0041] 1) Organic functionalization of graphene yields functionalized graphene;

[0042] 2) Anchoring bisphosphites onto functionalized graphene to obtain bisphosphite-anchored graphene;

[0043] 3) The transition metal was reacted with graphene anchored by bisphosphite to obtain a graphene-based heterogeneous catalyst.

[0044] This invention relates to the organic functionalization of graphene to obtain functionalized graphene. In this invention, the organic functionalization preferably involves reacting an organic compound with graphene to modify the graphene, forming connecting bonds with bisphosphites on the graphene. The organic compound preferably includes N-methylglycine, glycine, 1,2,4-pyrogallol, 3,4-dihydroxyphenylacetyl chloride, 4-chlorocatechol, and 3,4-dihydroxyphenylacetic acid.

[0045] In this invention, when N-methylglycine or glycine is reacted with graphene, the following operation is preferred:

[0046] A mixture of graphene and pyridine was ultrasonically dispersed. The resulting dispersion was then ultrasonically mixed with N,N-dimethylformamide, followed by the addition of N-methylglycine or glycine. 3,4-Dihydroxybenzaldehyde was then added dropwise at room temperature. After the addition was complete, the temperature was raised to 155°C, and the reaction was carried out under reflux and stirring for 60 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain functionalized graphene.

[0047] In this invention, when 1,2,4-phenylpyrogallol is reacted with graphene, the reaction is preferably carried out using the following operation:

[0048] Under a nitrogen atmosphere, a mixture of tetrahydrofuran and graphene oxide was ultrasonically dispersed. The resulting graphene oxide suspension was then ultrasonically mixed with 1,2,4-pyrogallol. Subsequently, the temperature was lowered to -30°C to -50°C, and 50 ml of n-butyllithium was added dropwise while stirring. The reaction temperature was maintained at -10°C to -20°C for 5 hours. After the reaction was completed, the n-butyllithium was quenched with deionized water, and then centrifuged, washed, and dried to obtain functionalized graphene.

[0049] In this invention, when 3,4-dihydroxyphenylacetyl chloride or 4-chlorocatechol is used to react with graphene, the reaction is preferably carried out using the following operation:

[0050] Under a nitrogen atmosphere, a mixture of diethyl ether and graphene was ultrasonically dispersed while the temperature was lowered to -10°C to -20°C. 3,4-Dihydroxyphenylacetyl chloride or 4-chlorocatechol was added to the diethyl ether to form a solution, and aluminum trichloride was added while maintaining the temperature at -10°C to 0°C. The reaction was allowed to proceed for 30 minutes. Immediately afterwards, the solution was slowly added dropwise to the graphene dispersion in diethyl ether, and the reaction continued for 48 hours. After the reaction was complete, the graphene was centrifuged, washed, and dried to obtain functionalized graphene.

[0051] In this invention, when 3,4-dihydroxyphenylacetic acid is reacted with graphene, the reaction is preferably carried out using the following operation:

[0052] Under a nitrogen atmosphere, a mixture of tetrahydrofuran and graphene oxide was ultrasonically dispersed to obtain a graphene oxide suspension. Under a nitrogen atmosphere, 3,4-dihydroxyphenylacetic acid was added to dichloromethane containing thionyl chloride and reacted at 50°C for 2 hours. The resulting reactant was cooled and then slowly added dropwise to the graphene oxide suspension, reacting at 50°C for 15 hours. After the reaction was complete, the mixture was centrifuged, washed, and dried sequentially to obtain functionalized graphene.

[0053] After obtaining functionalized graphene, this invention anchors bisphosphite onto the functionalized graphene to obtain bisphosphite-anchored graphene.

[0054] Preferably, the anchoring in step 2) is performed using the following steps:

[0055] a. React a mixture of monophosphite and phosphorus trichloride to obtain a halomonophosphite;

[0056] b. Functionalized graphene was mixed with tetrahydrofuran containing triethylamine and sonicated to obtain a dispersion;

[0057] c. A toluene solution of a halomonophosphite is added dropwise to a dispersion to react and obtain a graphene-based heterogeneous catalyst.

[0058] Preferably, the method for preparing the monophosphite includes the following steps:

[0059] (1) Mix material A with toluene or xylene, add phosphorus trichloride, and react to obtain intermediate A; the structural formula of material A is shown in Formula 2; the structural formula of intermediate A is shown in Formula 3;

[0060] (2) Intermediate A and material B are mixed and reacted to obtain monophosphite; the structural formula of material B is shown in Formula 4:

[0061]

[0062] The present invention also provides the application of the graphene-based heterogeneous catalyst described in any of the above embodiments in the catalytic hydroformylation of high carbon olefins; wherein the high carbon olefins are C6 to C20 olefins.

[0063] In this invention, the temperature of the hydroformylation reaction is preferably 50–150°C, more preferably 60–110°C. The gas used for the hydroformylation reaction is preferably a mixture of hydrogen and carbon monoxide; the volume ratio of hydrogen to carbon monoxide is preferably 20:1–1:20, more preferably 5:1–1:5; the pressure during the hydroformylation reaction is preferably 1–20 MPa, more preferably 3–8 MPa.

[0064] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] (1) Preparation of functionalized graphene

[0067] 2 g of graphene was added to 100 mL of pyridine and ultrasonically dispersed until homogeneous (ultrasonic power 350 W, time 10 min). The homogeneous pyridine dispersion was then poured into 1 L of N,N-dimethylformamide (DMF) and ultrasonically stirred until fully dispersed (ultrasonic power 350 W, stirring speed 50 rpm, time 10 min). Subsequently, 5 g of N-methylglycine was added. Then, 5 g of 3,4-dihydroxybenzaldehyde was added dropwise at room temperature. After the addition was complete, the temperature was raised to 155 °C, and the reaction was carried out under reflux and stirring for 60 hours. After the reaction was completed, the mixture was centrifuged at 12000 rpm. The black solid at the bottom of the centrifuge tube was washed with anhydrous ethanol and dried to obtain 2.5 g of functionalized graphene. The reaction is shown below:

[0068]

[0069] (2) Preparation of bisphosphite

[0070] ① Synthesis of monophosphites

[0071] 20.53 g (0.05 mol) of 3,3',5,5'-tetratert-butyl-[1,1'-biphenyl]-2,2'-diol was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise over 20 minutes with stirring. After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A. 9.31 g (0.05 mol) of 2,2-biphenol was dissolved in 100 mL of toluene solution. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form material B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued at room temperature with stirring for 5 hours. After the reaction was completed, triethylamine hydrochloride was removed by filtration, and crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300 g of a mixed solvent of acetonitrile and tetrahydrofuran (2:1 mass ratio) to obtain a white solid monophosphite with a mass of 28.95 g and a purity of 98%. The specific reaction process is as follows:

[0072]

[0073] ② Synthesis of halophosphites

[0074] 3.12 g (0.005 mol) of a white solid monophosphite was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 0.51 g (0.005 mol) of triethylamine was added. Following this, 0.69 g (0.005 mol) of phosphorus trichloride was added dropwise over 20 minutes with stirring. After the addition was complete, the temperature was raised to 75 °C and the reaction continued for 5 hours. After the reaction was complete, the triethylamine hydrochloride was removed by filtration, and the product was distilled under reduced pressure (0.07 MPa, 70 °C) to obtain a yellow solid halophosphite. The specific reaction procedure is as follows:

[0075]

[0076] (3) Synthesis of bisphosphite-anchored graphene

[0077] The above-mentioned halophosphite was dissolved in 100 mL of toluene to form solution C. 1.01 g (0.01 mol) of triethylamine was added to 500 mL of tetrahydrofuran solution, and 1 g of functionalized graphene was added to the triethylamine-tetrahydrofuran solution. The mixture was sonicated for 30 min to form a black, homogeneous dispersion D. Solution C was added dropwise to dispersion D over 20 min at room temperature, and the reaction was continued at room temperature for 5 hours. After the reaction was complete, triethylamine hydrochloride was first removed by centrifugation at 3000 rpm for 10 min. Then, the bisphosphite-anchored graphene was separated by centrifugation at 12000 rpm for 10 min. The graphene was washed three times with n-hexane.

[0078]

[0079] (4) Preparation of graphene-based heterogeneous catalysts

[0080] 0.5 g of the bisphosphite-anchored graphene obtained above was dispersed in a toluene solution, and 1.29 mg (0.05 mmol) of rhodium dicarbonyl acetylacetone was added. The mixture was stirred at room temperature for 30 minutes to allow the rhodium to complex with the bisphosphite on the graphene. The dispersion was then centrifuged and dried to obtain the graphene-based heterogeneous catalyst 1-1.

[0081] Example 2

[0082] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalyst is designated as 1-2. The specific method for synthesizing monophosphite is as follows:

[0083] 20.53 g (0.05 mol) of 3,3',5,5'-tetra-tert-butyl-[1,1'-biphenyl]-2,2'-diol was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise with stirring (dropping time controlled at 20 minutes). After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A solution. 20.53 g (0.05 mol) of 3,3',5,5'-tetra-tert-butyl-[1,1'-biphenyl]-2,2'-diol was dissolved in 100 mL of toluene solution, and then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form product B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued with stirring at room temperature for 5 hours. After the reaction was completed, triethylamine hydrochloride was removed by filtration, and crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300 g of a mixed solvent of acetonitrile and tetrahydrofuran in a 2:1 mass ratio to obtain a white solid monophosphite.

[0084] Example 3

[0085] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalysts are designated as 1-3. The specific method for synthesizing monophosphite is as follows:

[0086] 20.53 g (0.05 mol) of 3,3',5,5'-tetratert-butyl-[1,1'-biphenyl]-2,2'-diol was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise with stirring (dropping time controlled at 20 minutes). After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A solution. 17.93 g (0.05 mol) of 2,2'-dihydroxy-3,3'-ditert-butyl-5,5'-dimethoxydiphenylene was dissolved in 100 mL of toluene solution, and then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form product B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued with stirring at room temperature for 5 hours. After the reaction was completed, triethylamine hydrochloride was removed by filtration, and crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300 g of a mixed solvent of acetonitrile and tetrahydrofuran in a 2:1 mass ratio to obtain a white solid monophosphite.

[0087] Example 4

[0088] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalysts are designated as 1-4. The specific method for synthesizing monophosphite is as follows:

[0089] 9.31 g (0.05 mol) of 2,2-biphenol was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise over 20 minutes with stirring. After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A. 17.93 g (0.05 mol) of 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxydiphenylene was dissolved in 100 mL of toluene solution. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form material B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued at room temperature with stirring for 5 hours. After the reaction was completed, triethylamine hydrochloride was removed by filtration, and crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300 g of a mixed solvent of acetonitrile and tetrahydrofuran in a 2:1 mass ratio to obtain a white solid monophosphite.

[0090] Example 5

[0091] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalysts are designated as 1-5. The specific method for synthesizing monophosphite is as follows:

[0092] 9.31 g (0.05 mol) of 2,2-biphenyl was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise over 20 minutes with stirring. After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A. 20.53 g (0.05 mol) of 3,3',5,5'-tetratert-butyl-[1,1'-biphenyl]-2,2'-diol was dissolved in 100 mL of toluene solution. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form material B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued at room temperature with stirring for 5 hours. After the reaction was completed, triethylamine hydrochloride was removed by filtration, and crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300 g of a mixed solvent of acetonitrile and tetrahydrofuran in a 2:1 mass ratio to obtain a white solid monophosphite.

[0093] Example 6

[0094] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalysts are designated as 1-6. The specific method for synthesizing monophosphite is as follows:

[0095] 17.93 g (0.05 mol) of 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxydiphenyl was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise with stirring (dropping time controlled at 20 minutes). After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate solution A. 20.53 g (0.05 mol) of 3,3',5,5'-tetra-tert-butyl-[1,1'-biphenyl]-2,2'-diol was dissolved in 100 mL of toluene solution, and then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form solution B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued with stirring at room temperature for 5 hours. After the reaction was completed, triethylamine hydrochloride was removed by filtration, and crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300 g of a mixed solvent of acetonitrile and tetrahydrofuran in a 2:1 mass ratio to obtain a white solid monophosphite.

[0096] Example 7

[0097] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalysts are designated as 1-7. The specific method for synthesizing monophosphite is as follows:

[0098] 9.31 g (0.05 mol) of 2,2-biphenol was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise over 20 minutes with stirring. After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A. 9.31 g (0.05 mol) of 2,2-biphenol was dissolved in 100 mL of toluene solution, and then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form material B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued at room temperature with stirring for 5 hours. After the reaction was complete, triethylamine hydrochloride was removed by filtration, and the crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300g of a mixed solvent of acetonitrile and tetrahydrofuran in a mass ratio of 2:1 to obtain a white solid monophosphite.

[0099] Example 8

[0100] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalysts are designated as 1-8. The specific method for synthesizing monophosphite is as follows:

[0101] 17.93 g (0.05 mol) of 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxydiphenylene was dissolved in 100 mL of toluene solution. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise over 20 minutes with stirring. After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A. 9.31 g (0.05 mol) of 2,2-biphenol was dissolved in 100 mL of toluene solution. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form material B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued at room temperature with stirring for 5 hours. After the reaction was complete, triethylamine hydrochloride was removed by filtration, and the crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300g of a mixed solvent of acetonitrile and tetrahydrofuran in a mass ratio of 2:1 to obtain a white solid monophosphite.

[0102] Example 9

[0103] Except for the method for synthesizing monophosphite in step ①, the other operational steps are exactly the same as in Example 1. The obtained graphene-based catalysts are designated as 1-9. The specific method for synthesizing monophosphite is as follows:

[0104] 17.93 g (0.05 mol) of 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxydiphenylene was dissolved in 100 mL of toluene solution and transferred to a 500 mL three-necked flask equipped with a thermometer. Then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added. Next, while maintaining room temperature, 6.88 g (0.05 mol) of phosphorus trichloride was added dropwise with stirring (dropping time controlled at 20 minutes). After the addition was complete, the reaction was continued at room temperature for 5 hours to form intermediate A solution. 17.93 g (0.05 mol) of 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxydiphenylene was dissolved in 100 mL of toluene solution, and then, under nitrogen purging, 10.12 g (0.1 mol) of triethylamine was added to form product B. Material B was slowly injected into intermediate A over 30 minutes, and the reaction was continued with stirring at room temperature for 5 hours. After the reaction was completed, triethylamine hydrochloride was removed by filtration, and crude monophosphite was obtained by vacuum distillation. Recrystallization was performed using 300 g of a mixed solvent of acetonitrile and tetrahydrofuran in a 2:1 mass ratio to obtain a white solid monophosphite.

[0105] Example 10

[0106] Except for the method of preparing functionalized graphene in step (1), the other operation steps are exactly the same as in Example 1. The obtained graphene-based catalyst is referred to as 2-1. The specific method for preparing functionalized graphene is as follows:

[0107] 2 g of graphene was added to 100 mL of pyridine and sonicated to disperse it evenly (ultrasonic power 350 W, time 10 min). The evenly dispersed pyridine dispersion was then poured into 1 L of N,N-dimethylformamide (DMF) and sonicated while stirring to ensure complete dispersion (ultrasonic power 350 W, stirring speed 50 rpm, time 10 min). Subsequently, 4.22 g of glycine was added. Then, 5 g of 3,4-dihydroxybenzaldehyde was added dropwise at room temperature. After the addition was complete, the temperature was raised to 155 °C, and the reaction was carried out under reflux and stirring for 60 hours. After the reaction was completed, the mixture was centrifuged at 12000 rpm. The black solid at the bottom of the centrifuge tube was washed with anhydrous ethanol and dried to obtain 2.5 g of functionalized graphene.

[0108] The structural formula of the prepared graphene-based catalyst 2-1 is shown below:

[0109]

[0110] Example 11

[0111] Except for the method of preparing functionalized graphene in step (1), the other operation steps are exactly the same as in Example 1, and the obtained graphene-based catalyst is 3-1. The specific method for preparing functionalized graphene is as follows:

[0112] Under a nitrogen atmosphere, 2 g of graphene oxide was added to 1 L of tetrahydrofuran and ultrasonically dispersed until uniformly dispersed (ultrasonic power 350 W, time 10 min). Then, 5.3 g of 1,2,4-pyrogallol was added. The temperature was then lowered to between -30°C and -50°C, and 50 mL of n-butyllithium was added dropwise while stirring. The reaction temperature was maintained at -10°C to -20°C for 5 hours. After the reaction, the n-butyllithium was quenched with deionized water, and the mixture was centrifuged at 12000 rpm for 10 min. The black solid at the bottom of the centrifuge tube was washed with anhydrous ethanol. After drying, 2.32 g of functionalized graphene was obtained.

[0113] The structural formula of the prepared graphene-based catalyst 3-1 is shown below:

[0114]

[0115] Example 12

[0116] Except for the method of preparing functionalized graphene in step (1), the other operation steps are exactly the same as in Example 1, and the obtained graphene-based catalyst is 4-1. The specific method for preparing functionalized graphene is as follows:

[0117] Under a nitrogen atmosphere, 2 g of graphene was added to 1 L of diethyl ether and ultrasonically dispersed until uniformly dispersed (ultrasonic power 350 W, time 10 min). The temperature was then lowered to between -10°C and -20°C. 4.6 g of 3,4-dihydroxyphenylacetyl chloride was added to the diethyl ether solution, and 3 g of aluminum trichloride was added while maintaining the temperature at -10°C to 0°C. The reaction was allowed to proceed for 30 minutes. Immediately afterwards, the above solution was slowly added dropwise to the graphene dispersion in diethyl ether, and the reaction continued for 48 hours. The mixture was centrifuged at 12000 rpm. The black solid at the bottom of the centrifuge tube was washed three times with diethyl ether and once with ethanol. After drying, 2.5 g of functionalized graphene was obtained.

[0118] Example 13

[0119] Except for the method of preparing functionalized graphene in step (1), the other operation steps are exactly the same as in Example 1, and the obtained graphene-based catalyst is 5-1. The specific method for preparing functionalized graphene is as follows:

[0120] Under a nitrogen atmosphere, 2 g of graphene was added to 1 L of diethyl ether and ultrasonically dispersed until uniformly dispersed (ultrasonic power 350 W, time 10 min). The temperature was then lowered to -10°C to -20°C. 6 g of 4-chlorocatechol was added to the diethyl ether solution, and 3 g of aluminum trichloride was added while maintaining the temperature at -10°C to 0°C. The reaction was allowed to proceed for 30 minutes. Immediately afterwards, the above solution was slowly added dropwise to the graphene dispersion in diethyl ether, and the reaction continued for 48 hours. The mixture was centrifuged at 12000 rpm. The black solid at the bottom of the centrifuge tube was washed three times with diethyl ether and once with ethanol. After drying, 2.29 g of functionalized graphene was obtained.

[0121] Example 14

[0122] Except for the method of preparing functionalized graphene in step (1), the other operation steps are exactly the same as in Example 1, and the obtained graphene-based catalyst is 6-1. The specific method for preparing functionalized graphene is as follows:

[0123] Under a nitrogen atmosphere, 2 g of graphene oxide was added to 1 L of tetrahydrofuran and ultrasonically dispersed until uniform (ultrasonic power 350 W, time 10 min) for later use. Under a nitrogen atmosphere, 3 g of 3,4-dihydroxyphenylacetic acid was added to 100 ml of dichloromethane containing 2.30 g of thionyl chloride and reacted at 50 °C for 2 hours. After cooling, the solution was slowly added dropwise to the graphene oxide suspension and reacted at 50 °C for 15 hours. After the reaction was complete, the solution was centrifuged at 12000 rpm, and the black solid at the bottom of the centrifuge tube was washed with anhydrous ethanol. After drying, 2.21 g of functionalized graphene was obtained.

[0124] Example 15

[0125] The catalysts prepared in Examples 1-9 above were used to catalyze the hydroformylation reaction of 1-octene, and the specific operations are as follows:

[0126] 0.5 g of graphene-based heterogeneous catalyst was added to 56.11 g (0.5 mol) of 1-octene. The mixture was then introduced into a 100 mL high-pressure reactor with a 1 / 1 volume ratio of carbon monoxide / hydrogen gas at 3 MPa, and reacted at 110 °C for 8 hours. After the reaction, the reaction solution was filtered, and the filter residue was the recovered catalyst. Using n-dodecane as an internal standard, the substrate conversion and selectivity of the filtrate were determined by gas chromatography. The experimental results are shown in Table 1.

[0127] Table 1. Effects of catalysis on 1-octene

[0128]

[0129]

[0130] Example 16

[0131] The catalysts prepared in Examples 1 and 10-14 above were used to catalyze the hydroformylation reaction of 7-octen-1-aldehyde, and the specific operations are as follows:

[0132] 0.5 g of graphene-based heterogeneous catalyst was added to 63.10 g (0.5 mol) of 7-octen-1-al. The mixture was placed in a 100 mL high-pressure reactor and purged with a 1 / 1 volume ratio of carbon monoxide / hydrogen gas at 3 MPa. The reaction was carried out at 110 °C for 8 hours. After the reaction, the reaction solution was filtered, and the filter residue was the recovered catalyst. The substrate conversion and selectivity were determined by gas chromatography. The linear product was 1,9-nonadialdehyde, and the branched product was 2-methyl-1,8-octanedialdehyde. The experimental results are as follows:

[0133] Table 2. Catalytic effect on 7-octen-1-aldehyde

[0134]

[0135] Example 17

[0136] The catalysts recovered after the reactions in Examples 15 and 16 were used to carry out the reactions again, and each reaction was repeated 10 times under the same conditions. The yield of the catalyst and the specific results of the hydroformylation reaction were measured after 10 reactions. The specific results are shown in Table 3.

[0137] Table 3 Catalytic effect of the 10th reaction

[0138]

[0139] As can be seen from Table 3, the catalyst provided by the present invention has high stability and long service life after 10 cycles (a total of 80 hours of reaction).

[0140] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of a graphene-based heterogeneous catalyst in the catalysis of the hydroformylation of higher alkenes, characterized in that, The catalyst comprises graphene, bisphosphite and transition metal, the bisphosphite is anchored on graphene by chemical bond; the structural formula of the bisphosphite anchored on graphene is shown as formula 1: Formula 1 Wherein, X is single bond, -O-, nitrogen-containing heterocycle, -S-, acyl or ester bond; The R1, R2, R3 and R4 groups are independently one of M1~M9 respectively; the M1~M9 have the following structural formula: ； The high-carbon olefin is C6~C20 olefin; The graphene-based heterogeneous catalyst is prepared by the following steps: 1) organic functionalization of graphene to obtain functionalized graphene; 2) anchoring bisphosphite on functionalized graphene to obtain bisphosphite-anchored graphene; 3) reacting transition metal with bisphosphite-anchored graphene to obtain graphene-based heterogeneous catalyst; The organic functionalization is to react organic matter with graphene to form a connecting bond connected with bisphosphite on graphene; the organic matter includes N-methyl glycine, glycine, 1,2,4-benzene triol, 3,4-dihydroxyphenyl acetyl chloride, 4-chloro catechol and 3,4-dihydroxyphenyl acetic acid.

2. Use according to claim 1, characterized in that, The X bond is L1~L5 。 3. Use according to claim 1, characterized in that, The graphene in the catalyst is hexagonal honeycomb, the number of layers is 1~10 layers; the addition amount of the transition metal is 1 / 100~1 / 100000 of the total mass of graphene and bisphosphite.

4. Use according to claim 1, characterized in that, The anchoring in step 2) adopts the following steps: a. mixing and reacting monophosphite with phosphorus trichloride to obtain halogenated monophosphite; b. mixing functionalized graphene with tetrahydrofuran containing triethylamine and ultrasonic to obtain a dispersion liquid; c. dropping the toluene solution of halogenated monophosphite into the dispersion liquid to obtain bisphosphite-anchored graphene.

5. Use according to claim 4, characterized in that, The preparation method of the monophosphite comprises the following steps: (1) mixing material A with toluene or xylene, adding phosphorus trichloride and reacting to obtain intermediate A; the structural formula of the material A is shown as formula 2; the structural formula of the intermediate A is shown as formula 3; (2) mixing intermediate A with material B and reacting to obtain monophosphite; the structural formula of the material B is shown as formula 4:

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