Polydentate nitrogen phosphine ligand as well as preparation method and application thereof

Abstract

The invention provides a preparation method of a polydentate nitrogen phosphine ligand. The preparation method comprises the following steps: 1) reacting 3-bromoindole with disubstituted amine under the action of a catalyst and a ligand to prepare 3-aminoindole; and 2) carrying out a reaction on 3-aminoindole and disubstituted phosphine chloride to prepare the polydentate nitrogen phosphine ligand. The polydentate nitrogen-phosphorus ligand prepared by the method is used for the hydroformylation reaction of olefin, and has the advantages of convenience in synthesis, high conversion rate of the hydroformylation reaction, high normal / isomeric ratio, good selectivity and the like.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a multidentate nitrogen phosphine ligand and a preparation method and application thereof. Background Art

[0002] In the chemical industry, hydroformylation is an important method for synthesizing alcohol compounds due to its excellent atom economy. This process uses olefins and synthesis gas to efficiently convert them into corresponding aldehydes or alcohols under the action of catalysts. This method has a wide range of applications in industrial production. In particular, the high-yield synthesis of linear aldehydes and alcohols is the focus of current research.

[0003] At present, the hydroformylation reaction in industry is mainly carried out under homogeneous conditions, with Rh and Co metal complexes as catalysts, mainly PPh3 and bidentate phosphite ligands (Biphephos) used by Dow Chemical. However, the linear aldehyde selectivity is low, and the ligand is unstable, so the ligand needs to be added from time to time to ensure the catalytic activity.

[0004] Patent US2019 / 0358915A1 proposes a new type of multidentate nitrogen phosphine ligand, which can adjust the performance of the catalyst by changing the electronic and stereochemical properties of the ligand, and can improve the selectivity of linear aldehydes in the hydroformylation reaction. Patent CN116283501A relates to a new type of biphenyl tetradentate phosphite ligand, which can achieve a higher conversion rate and iso-ratio in the hydroformylation reaction of mixed / etherified carbon four. However, the above methods all have the problem of complex synthesis steps.

[0005] In summary, while exploring ways to improve the conversion rate, iso-ratio, and selectivity of the hydroformylation reaction, it is also necessary to comprehensively consider simplifying the synthesis operation. Summary of the invention

[0006] The object of the present invention is to provide a multidentate nitrogen phosphine ligand and a preparation method thereof, wherein the multidentate nitrogen phosphine ligand is used for the hydroformylation reaction of olefins, the synthesis operation is simplified, and the advantages of high conversion rate, high iso-ratio, good selectivity and the like of the hydroformylation reaction are achieved.

[0007] In order to achieve the above invention object, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a multidentate nitrogen phosphine ligand, wherein the multidentate nitrogen phosphine ligand has a structure as shown in formula (1):

[0009]

[0010] Among them, R 1 , R 2Each is independently selected from methyl, ethyl, propyl, n-propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl or phenyl, preferably ethyl, isopropyl, cyclohexyl or phenyl, R 1 and R 2 Same or different; each R 3 Independently selected from phenyl, norbornyl, cyclohexyl, n-butyl or tert-butyl, preferably phenyl, norbornyl or tert-butyl.

[0011] According to the multidentate nitrogen phosphine ligand of the present invention, the multidentate nitrogen phosphine ligand has a structure as shown in formula (L1), (L2) or (L3):

[0012]

[0013] Another object of the present invention is to provide a method for preparing a multidentate nitrogen phosphine ligand as shown in the above formula (1), comprising the following steps:

[0014] 1) 3-halogenated indole reacts with disubstituted amine under the action of a catalyst and a catalyst promoter to obtain 3-aminoindole;

[0015] 2) 3-Aminoindole reacts with disubstituted chlorophosphine to prepare a multidentate nitrogen phosphine ligand of formula (1).

[0016] According to the preparation method of the present invention, in step 1), the disubstituted amine has a structure as shown in formula (2),

[0017] Where R 1 , R 2 With R in formula (1) 1 , R 2 same;

[0018] That is, R 1 , R 2 Each is independently selected from methyl, ethyl, propyl, n-propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl or phenyl, preferably ethyl, isopropyl, cyclohexyl or phenyl, R 1 and R 2 Same or different;

[0019] Preferably, the disubstituted amine is selected from at least one of N-ethylaniline, diisopropylamine and dicyclohexylamine.

[0020] According to the preparation method of the present invention, in step 1), the 3-aminoindole has a structure as shown in formula (3),

[0021] Where R 1 , R 2 With R in formula (1) 1 , R2 same;

[0022] That is, R 1 , R 2 Each is independently selected from methyl, ethyl, propyl, n-propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl or phenyl, preferably ethyl, isopropyl, cyclohexyl or phenyl, R 1 and R 2 Same or different.

[0023] According to the preparation method of the present invention, wherein in step 1), the catalyst is selected from a palladium catalyst, preferably palladium acetate, palladium chloride, tris dibenzylideneacetone dipalladium, and more preferably tris dibenzylideneacetone dipalladium.

[0024] According to the preparation method of the present invention, in step 1), the catalyst promoter is selected from triphenylphosphine, tricyclohexylphosphine (TCHP), and / or 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP), preferably 1,1'-binaphthyl-2,2'-bisdiphenylphosphine.

[0025] According to the preparation method of the present invention, in step 1), the 3-halogenated indole is selected from 3-chloroindole, 3-bromoindole or 3-iodoindole, preferably 3-chloroindole or 3-bromoindole.

[0026] According to the preparation method of the present invention, in step 1), the reaction is carried out in an alkaline environment, and the base used is selected from inorganic bases, preferably potassium carbonate and / or cesium carbonate, more preferably cesium carbonate.

[0027] According to the preparation method of the present invention, in step 1), the amount of the disubstituted amine added is 1-2 times, preferably 1-1.5 times, the molar amount of the 3-haloindole.

[0028] According to the preparation method of the present invention, in step 1), the amount of the catalyst added is 1-10%, preferably 2-5%, of the molar amount of 3-haloindole.

[0029] According to the preparation method of the present invention, in step 1), the amount of the catalyst aid added is 2-20% of the molar amount of 3-halogenated indole, preferably 5-10%.

[0030] According to the preparation method of the present invention, in step 1), the amount of base added is 2-5 times, preferably 2-3 times, the molar amount of 3-haloindole.

[0031] According to the preparation method of the present invention, in step 1), the reaction temperature is 90-150° C., preferably 100-130° C., and the reaction time is 5-20 h, preferably 6-15 h (the reaction time does not include the above-mentioned catalyst addition time).

[0032] According to the preparation method of the present invention, wherein, in step 1), the reaction is carried out in a solvent environment, and the solvent is selected from toluene, tert-butanol, and / or tetrahydrofuran, preferably toluene;

[0033] The amount of the solvent used is 0.5-5 mL / g, preferably 0.5-2 mL / g, calculated based on the mass of the 3-bromoindole raw material.

[0034] According to the preparation method of the present invention, in step 1), after the reaction is completed, the reaction solution is diluted, filtered, concentrated, and subjected to column chromatography to obtain the 3-aminoindole. The post-treatment operations such as dilution, filtration, concentration, and column chromatography are conventional operations in the art, such as adding ethyl acetate for dilution, filtering and concentrating, and purifying and separating by column chromatography, etc., and the present invention does not make specific limitations.

[0035] In one embodiment, step 1) of the present invention specifically adopts the following process: weigh the Pd catalyst and the catalytic aid and disperse them in a solvent, add the catalyst solution and a certain amount of 3-bromoindole, disubstituted amine, cesium carbonate and solvent into a reaction bottle, react at 100-130° C. for 6-15 hours, and after the reaction is completed, dilute the reaction solution with ethyl acetate, filter and concentrate, and separate and purify it by silica gel column chromatography to obtain 3-aminoindole.

[0036] According to the preparation method of the present invention, in step 2), the disubstituted chlorophosphine has a structure as shown in formula (4),

[0037] P(R 3 )2Cl(4), where R 3 With R in formula (1) 3 same;

[0038] That is, each R 3 Independently selected from phenyl, norbornyl, cyclohexyl, n-butyl or tert-butyl, preferably phenyl, norbornyl or tert-butyl;

[0039] Preferably, the disubstituted chlorophosphine is selected from at least one of diphenyl chlorophosphine, dinorbornyl chlorophosphine and di-tert-butyl chlorophosphine.

[0040] According to the preparation method of the present invention, in step 2), 3-aminoindole and disubstituted chlorophosphine undergo Suzuki-Miyaura coupling reaction to obtain a multidentate nitrogen phosphine ligand shown in formula (1). Suzuki-Miyaura coupling reaction is a conventional operation in the art and is not specifically limited in the present invention.

[0041] In one embodiment, step 2) of the present invention specifically adopts the following process: 3-aminoindole and a solvent are mixed, n-butyl lithium is added dropwise at -78°C, and after the addition is completed, the mixture is stirred at 20-30°C for 4-6 hours, the reaction solution is cooled to -78°C and a disubstituted chlorophosphine is added dropwise within 10-30 minutes, after the addition is completed, the reaction system is reacted at 0-25°C for 20-30 hours, the solvent is removed in vacuo, and an aqueous hydrochloric acid solution is added, and the mixture is reacted at 50-70°C for 2-5 hours. After the reaction is completed, the mixture is extracted twice with dichloromethane, the organic phases are combined and dried with anhydrous Na2SO4, concentrated under reduced pressure, and the multidentate nitrogen phosphine ligand is separated and purified by column chromatography.

[0042] Another object of the present invention is to provide the use of the multidentate nitrogen phosphine ligand in the hydroformylation reaction of olefins;

[0043] The olefin is a C2-C12 monoolefin, preferably propylene, 1-butene, pentene, octene, heptene, and n-dodecene.

[0044] The present invention also provides a method for hydroformylation of olefins. The method comprises the following steps: in a solvent environment, a multidentate nitrogen phosphine ligand and a transition metal catalyst are used together to catalyze the hydroformylation of olefins and synthesis gas.

[0045] According to the olefin hydroformylation method of the present invention, the reaction formula of the hydroformylation reaction is as follows:

[0046]

[0047] Among them, the It is a C2-C12 monoolefin, preferably propylene, 1-butene, pentene, octene, heptene, and n-dodecene; M represents a transition metal catalyst, L represents a multidentate nitrogen phosphine ligand, and the multidentate nitrogen phosphine ligand is the multidentate nitrogen phosphine ligand as described above.

[0048] According to the olefin hydroformylation reaction method of the present invention, the transition metal catalyst is selected from one or more of rhodium acetate, rhodium octanoate, rhodium acetylacetonate, rhodium acetylacetonate carbonyl rhodium, dicarbonyl acetylacetonate rhodium, triphenylphosphine acetylacetonate rhodium, cobalt acetate, cobalt octanoate, cobalt acetylacetonate, cobalt acetylacetonate carbonyl cobalt, and triphenylphosphine acetylacetonate cobalt.

[0049] According to the olefin hydroformylation reaction method of the present invention, the amount of the transition metal catalyst used is 0.02-0.2% of the molar amount of the olefin calculated as metal atoms, preferably 0.05-0.2%.

[0050] According to the olefin hydroformylation reaction method of the present invention, the amount of the multidentate nitrogen phosphine ligand is 5-50 times, preferably 10-30 times, the molar amount of the metal atom in the transition metal catalyst.

[0051] According to the olefin hydroformylation reaction method of the present invention, the hydroformylation reaction is carried out in a solvent, wherein the solvent is selected from at least one of tetrahydrofuran, 1,4-dioxane, benzene, and toluene, more preferably 1,4-dioxane and / or toluene;

[0052] The amount of the solvent added is 10-100 times, more preferably 10-30 times, the molar amount of the olefin.

[0053] According to the olefin hydroformylation method of the present invention, the reaction temperature of the hydroformylation reaction is 90-200° C., preferably 100-180° C., and the reaction time is 1-15 h, preferably 3-12 h.

[0054] According to the olefin hydroformylation reaction method of the present invention, the reaction pressure of the hydroformylation reaction is 1.0-20 MPaG, preferably 1.0-4.0 MPaG, and the reaction pressure is regulated by synthesis gas, and the CO / H2 molar ratio in the synthesis gas is 1:0.5-1.5, preferably 1:1.

[0055] The multidentate nitrogen phosphine ligand of the present invention, in the presence of a transition metal catalyst, since each multidentate nitrogen phosphine ligand has two coordination active sites, the transition metal coordinates with P and N of one multidentate nitrogen phosphine ligand, coordinates with P of another multidentate nitrogen phosphine ligand and forms a hydrogen bond with H, forming a coordination form of two five-membered rings and stabilizing the metal, and the substituents around P and N in the multidentate nitrogen phosphine ligand form a large steric hindrance, making it easier for the carbonyl group to add to the olefin terminal after participating in the coordination, thereby obtaining a higher linear selectivity (95-97.3%), as shown in the following diagram:

[0056] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0057] (1) The multidentate nitrogen phosphine ligand of the present invention has a strong coordination ability with transition metals, and the large steric hindrance makes the terminal reaction highly selective, thereby promoting the formation of linear aldehydes.

[0058] (2) The multidentate nitrogen phosphine ligand of the present invention is used to carry out hydroformylation reaction to prepare linear aldehydes, and the process conditions are simple and safe, and the normal-to-iso ratio is high. DETAILED DESCRIPTION

[0059] The following examples will further illustrate the method provided by the present invention, but the present invention is not limited to the listed examples, and should also include any other known changes within the scope of the rights claimed by the present invention.

[0060] The main analysis methods used in the embodiments of the present invention are:

[0061] The reactions of 3-bromoindole, disubstituted chlorophosphine, 3-aminoindole and disubstituted chlorophosphine were followed by gas chromatography, and the conversion of olefins and the selectivity of aldehydes were calculated by gas chromatography area normalization: Gas chromatograph: Agilent 7890; chromatographic column: DB-5; inlet temperature: 280°C; split ratio 10:1; H2:Air:N2=40:400:30 (mL / min); column flow rate 5.0 mL / min; heating program: 50°C for 2 min, heating from 50°C to 280°C at a rate of 15°C / min, and 280°C for 5 min; FID detector temperature: 280°C.

[0062] Characterization methods of polydentate nitrogen phosphine ligands: 1 H NMR, instrument model: Bruker 500 MHz nuclear magnetic resonance instrument.

[0063] Source information of the main reagents used in the embodiments of the present invention:

[0064] 3-Bromoindole (AR), dicyclohexylamine (AR), diphenylphosphine chloride (AR), dinorbornylphosphine chloride (AR), di-tert-butylphosphine chloride (AR), triphenylphosphine (AR), tricyclohexylphosphine (AR), 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (AR), THF (AR), toluene (AR), ethyl acetate (AR), cesium carbonate (AR): purchased from Inokane;

[0065] Unless otherwise specified, other raw materials were commercially available and reagents were of analytical grade.

[0066] Example 1

[0067] The steps for preparing the multidentate nitrogen-phosphorus ligand L1 are as follows:

[0068]

[0069] (1) The catalyst palladium acetate (0.05 mol, 11.3 g) and the catalyst co-agent 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP, 0.05 mol, 31.1 g) were weighed and dispersed in 200 mL of tert-butyl alcohol solvent. The catalyst solution and 3-chloroindole (1 mol, 151.6 g), N-ethylaniline (2 mol, 242.4 g), cesium carbonate (2.5 mol, 814.6 g) and 250 mL of tert-butyl alcohol solvent were added to a reaction kettle. The reaction system was heated to 100° C. and reacted for 15 h. After the reaction was completed, the reaction solution was diluted with ethyl acetate, filtered, concentrated, and separated and purified by silica gel column chromatography to obtain 3-aminoindole intermediate (I) (0.91 mol, 215.0 g).

[0070] The H NMR spectrum of intermediate (I) is: 1H NMR (500MHz, CDCl3): δ=7.66–7.59(m,1H),7.52(s,1H),7.48–7.40(m,1H),7.25–7.15(m,4H),7 .15–7.07(m,2H),7.07–6.99(m,1H),6.86(s,1H),3.10(q,J=8.0Hz,2H),1.29(t,J=8.0Hz,3H).

[0071] (2) The intermediate (I) (0.05 mol, 11.8 g) and tetrahydrofuran solvent were mixed, and n-butyl lithium (0.02 mol, 2.5 M in hexanes, 8 mL) was added dropwise at -78°C. After the addition was completed, the mixture was stirred at 20-30°C for 4-6 h. The reaction solution was cooled to -78°C and diphenylphosphine chloride (0.05 mol, 11.0 g) was added dropwise within 10-30 min. After the addition was completed, the reaction system was reacted at 0-25°C for 20-30 h. The solvent was removed in vacuo and aqueous hydrochloric acid solution was added. The mixture was reacted at 50-70°C for 2-5 h. After the reaction was completed, the mixture was extracted twice with dichloromethane. The organic phases were combined and dried over anhydrous Na2SO4, concentrated under reduced pressure, and the polydentate nitrogen phosphine ligand L1 (0.043 mol, 18.1 g) was separated and purified by column chromatography.

[0072] The H NMR spectrum data of the multidentate nitrogen phosphine ligand L1 are: 1 H NMR (500MHz, CDCl3): δ=8.09(s,1H),7.78(s,1H),7.49–7.43(m,5H),7.35–7.28(m,6H),7.24 (s,2H),7.12(s,3H),7.03(s,1H),6.72(s,1H),3.10(q,J=8.0Hz,2H),1.15(t,J=8.0Hz,3H).

[0073] Application Example 1

[0074] Propylene hydroformylation to prepare n-butyraldehyde, the steps are:

[0075] Propylene, acetylacetonato carbonyl cobalt catalyst, multidentate nitrogen-phosphorus ligand L1, and toluene are added to the reactor, wherein the molar amount of cobalt in the acetylacetonato carbonyl cobalt catalyst is 0.2% of the molar amount of propylene, the multidentate nitrogen-phosphorus ligand L1 is 50 times the molar amount of cobalt in the cobalt catalyst, and the toluene is 10 times the molar amount of propylene. Then, synthesis gas (CO / H2 molar ratio is 1:1) is introduced, and the reaction is carried out at a pressure of 12MPaG and a temperature of 180°C for 12 hours. According to gas chromatography analysis, the propylene conversion rate is 97.9%, the selectivity of the linear product n-butyraldehyde is 96.3%, and the selectivity of 2-methylpropanal (isobutyraldehyde) is 1.1%.

[0076] Example 2

[0077] The steps for preparing the multidentate nitrogen-phosphorus ligand L2 are as follows:

[0078]

[0079] (1) The catalyst tris(dibenzylideneacetone)dipalladium (Pd2(dba)3, 0.02 mol, 18.3 g) and the catalyst promoter triphenylphosphine (0.2 mol, 52.5 g) were weighed and dispersed in 100 mL of toluene solvent. The catalyst solution and 3-bromoindole (1 mol, 196.0 g), diisopropylamine (1 mol, 101.2 g), cesium carbonate (2.0 mol, 651.6 g) and 100 mL of toluene solvent were added to a reaction kettle. The reaction system was heated to 130° C. and reacted for 6 h. After the reaction was completed, the reaction solution was diluted with ethyl acetate, filtered, concentrated, and separated and purified by silica gel column chromatography to obtain 3-aminoindole intermediate (II) (0.90 mol, 194.7 g).

[0080] The H NMR spectrum of intermediate (II) is: 1 H NMR (500MHz, CDCl3): δ=7.69–7.63(m,1H),7.40(s,1H),7.38–7.32(m,1H),7.15–7.05(m,2H),6.84(s,1H),4.73–

[0081] 4.61(m,2H),1.34(d,J=6.8Hz,12H).

[0082] (2) The intermediate (II) (0.05 mol, 10.8 g) and tetrahydrofuran solvent were mixed, and n-butyl lithium (0.02 mol, 2.5 M in hexanes, 8 mL) was added dropwise at -78°C. After the addition was completed, the mixture was stirred at 20-30°C for 4-6 h. The reaction solution was cooled to -78°C and dinorbornyl chlorophosphine (0.05 mol, 12.8 g) was added dropwise over 10-30 min. After the addition was completed, the reaction system was reacted at 0-25°C for 20-30 h. The solvent was removed in vacuo and aqueous hydrochloric acid solution was added. The mixture was reacted at 50-70°C for 2-5 h. After the reaction was completed, the mixture was extracted twice with dichloromethane. The organic phases were combined and dried over anhydrous Na2SO4, and concentrated under reduced pressure. The polydentate nitrogen phosphine ligand L2 (0.041 mol, 17.9 g) was separated and purified by column chromatography.

[0083] The H NMR spectrum data of the multidentate nitrogen phosphine ligand L2 are: 1 H NMR (500MHz, CDCl3): δ = 8.21 (s, 1H) ，8.09(d,J=7.5Hz,1H),7.78(d,J=7.5Hz,1H),7.12(t,J=7.5Hz,1H),6.72(t,J=7.5Hz,1H),5.05(s,2H),2.3 5(s,2H),1.70–1.63(m,2H),1.63–1.53(m,2H),1.53–1.43(m,4H),1.43–1.27(m,10H),1.26–1.16(m,14H).

[0084] Application Example 2

[0085] Hexene is hydroformylated to prepare n-heptanal, the steps are:

[0086] Hexene, dicarbonyl acetylacetonate rhodium catalyst, multidentate nitrogen-phosphorus ligand L2, and toluene are added to a reactor, wherein the molar amount of rhodium in the dicarbonyl acetylacetonate rhodium catalyst is 0.05% of the molar amount of hexene, the multidentate nitrogen-phosphorus ligand L2 is 20 times the molar amount of rhodium in the rhodium catalyst, and the toluene is 20 times the molar amount of hexene. Then, synthesis gas (CO / H2 molar ratio is 1:1) is introduced, and the reaction is carried out at a pressure of 3MPaG and a temperature of 100°C for 4 hours. According to gas chromatography analysis, the hexene conversion rate is 99.2%, the linear product n-heptanal selectivity is 98.7%, and the n-heptanal selectivity is 0.7%.

[0087] Example 3

[0088] The steps for preparing the multidentate nitrogen-phosphorus ligand L3 are as follows:

[0089]

[0090] (1) The catalyst tris(dibenzylideneacetone)dipalladium (Pd2(dba)3, 0.02 mol, 18.3 g) and the catalyst co-agent tricyclohexylphosphine (0.1 mol, 28.0 g) were weighed and dispersed in 200 mL of tetrahydrofuran solvent. The catalyst solution and 3-bromoindole (1 mol, 196.0 g), dicyclohexylamine (1.5 mol, 272.0 g), potassium carbonate (3.0 mol, 414.6 g) and 200 mL of tetrahydrofuran solvent were added to a reaction kettle. The reaction system was heated to 90° C. and reacted for 20 h. After the reaction was completed, the reaction solution was diluted with ethyl acetate, filtered, concentrated, and separated and purified by silica gel column chromatography to obtain 3-aminoindole intermediate (III) (0.95 mol, 281.6 g).

[0091] The H NMR spectrum of intermediate (III) is: 1H NMR (500MHz, CDCl3): δ=7.69–7.63(m,1H),7.51(s,1H),7.38–7.31(m,1H),7.15–7.05(m,2H),6.9 7(s,1H),2.71(s,2H),1.97–1.86(m,4H),1.80–1.68(m,4H),1.65–1.57(m,4H),1.45–1.32(m,8H).

[0092] (2) The intermediate (III) (0.05 mol, 14.8 g) and tetrahydrofuran solvent were mixed, and n-butyl lithium (0.02 mol, 2.5 M in hexanes, 8 mL) was added dropwise at -78°C. After the addition was completed, the mixture was stirred at 20-30°C for 4-6 h. The reaction solution was cooled to -78°C and di-tert-butylphosphine chloride (0.05 mol, 11.6 g) was added dropwise over 10-30 min. After the addition was completed, the reaction system was reacted at 0-25°C for 20-30 h. The solvent was removed in vacuo and aqueous hydrochloric acid solution was added. The mixture was reacted at 50-70°C for 2-5 h. After the reaction was completed, the mixture was extracted twice with dichloromethane. The organic phases were combined and dried over anhydrous Na2SO4, and concentrated under reduced pressure. The polydentate nitrogen phosphine ligand L3 (0.04 mol, 17.6 g) was separated and purified by column chromatography.

[0093] The H NMR spectrum data of the multidentate nitrogen phosphine ligand L3 are: 1 H NMR (500MHz, CDCl3): δ = 8.34 (s, 1H), 8.09 (d, J = 7.5Hz, 1H), 7.78 (d, J = 7.5Hz, 1H), 7.12 (t, J = 7.5Hz, 1H), 6.72 (t, J = 7.5Hz,1H),2.95(s,2H),1.80–1.69(m,4H),1.69–1.62(m,4H),1.55–1.47(m,6H),1.47–1.39(m,6H),1.06(s,18H).

[0094] The steps of preparing tridecaldehyde by hydroformylation of n-dodecene are as follows:

[0095] n-dodecene, triphenylphosphine acetylacetone rhodium catalyst, multidentate nitrogen-phosphorus ligand L3, and 1,4-dioxane were added to the reactor, wherein the molar amount of rhodium in the triphenylphosphine acetylacetone rhodium catalyst was 0.1% of the molar amount of n-dodecene, the multidentate nitrogen-phosphorus ligand L3 was 30 times the molar amount of rhodium in the rhodium catalyst, and 1,4-dioxane was 30 times the molar amount of n-dodecene. Then, synthesis gas (CO / H2 molar ratio of 1:1) was introduced, and the reaction was carried out at a pressure of 8MPaG and a temperature of 150°C for 5 hours. According to gas chromatography analysis, the conversion rate of n-dodecene was 98.3%, and the selectivity of the linear product n-tridecanal was 96.7%, and the selectivity of isotridecanal was 0.8%.

[0096] Comparative Example 1

[0097] The method of Example 3 was used to prepare tridecaldehyde by hydroformylation of n-dodecene, except that the ligand L3 was replaced by an equal amount of triphenylphosphine, and the other operations and parameters remained unchanged. According to gas chromatography analysis, the hexene conversion rate was 79.5%, the selectivity of the linear product tridecaldehyde was 80.3%, and the selectivity of isotridecanal was 12.6%.

Claims

1. A multidentate nitrogen phosphine ligand, wherein the multidentate nitrogen phosphine ligand has a structure as shown in formula (1): in, R 1 , R 2 Each is independently selected from methyl, ethyl, propyl, n-propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl or phenyl, preferably ethyl, isopropyl, cyclohexyl or phenyl, R 1 and R 2 Same or different; each R 3 Independently selected from phenyl, norbornyl, cyclohexyl, n-butyl or tert-butyl, preferably phenyl, norbornyl or tert-butyl.

2. The multidentate nitrogen phosphine ligand according to claim 1, wherein The polydentate nitrogen phosphine ligand has a structure as shown in formula (L1), (L2) or (L3):

3. A method for preparing a multidentate nitrogen phosphine ligand as claimed in claim 1 or 2, comprising the following steps: 1) 3-halogenated indole reacts with disubstituted amine in the presence of a catalyst and a catalyst promoter to obtain 3-aminoindole; 2) 3-Aminoindole reacts with disubstituted chlorophosphine to prepare a multidentate nitrogen phosphine ligand of formula (1).

4. The preparation method according to claim 3, wherein In step 1), The disubstituted amine has a structure as shown in formula (2), The 3-aminoindole has a structure as shown in formula (3), Where R 1 , R 2 As defined in claim 1.

5. The preparation method according to claim 3 or 4, wherein In step 1), The catalyst is selected from palladium catalysts, preferably palladium acetate, palladium chloride, tris dibenzylideneacetone dipalladium, more preferably tris dibenzylideneacetone dipalladium; Preferably, the catalyst promoter is selected from triphenylphosphine, tricyclohexylphosphine (TCHP), and / or 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP), preferably 1,1'-binaphthyl-2,2'-bisdiphenylphosphine; Preferably, the 3-haloindole is selected from 3-chloroindole, 3-bromoindole, 3-fluoroindole or 3-iodoindole, preferably 3-chloroindole or 3-bromoindole; Preferably, the reaction is carried out in an alkaline environment, and the base used is selected from inorganic bases, preferably potassium carbonate and / or cesium carbonate, more preferably cesium carbonate.

6. The preparation method according to claim 5, wherein: In step 1), The amount of the disubstituted amine added is 1-2 times the molar amount of the 3-halogenated indole, preferably 1-1.5 times; Preferably, the catalyst is added in an amount of 1-10% of the molar amount of 3-haloindole, preferably 2-5%; Preferably, the catalyst promoter is added in an amount of 2-20% of the molar amount of 3-halogenated indole, preferably 5-10%; Preferably, the amount of base added is 2-5 times, preferably 2-3 times, the molar amount of 3-haloindole; Preferably, the reaction temperature is 90-150°C, preferably 100-130°C, and the reaction time is 5-20h, preferably 6-15h; Preferably, the reaction is carried out in a solvent environment, the solvent is selected from toluene, tert-butyl alcohol, and / or tetrahydrofuran, preferably toluene; preferably, the amount of the solvent, calculated based on the mass of the 3-bromoindole raw material, is 0.5-5 mL / g, preferably 0.5-2 mL / g; Preferably, after the reaction is completed, the reaction solution is diluted, filtered, concentrated, and subjected to column chromatography to obtain the 3-aminoindole.

7. The preparation method according to any one of claims 3 to 6, wherein In step 2), The disubstituted chlorophosphine has a structure as shown in formula (4), P(R 3 )2Cl(4), where R 3 As defined in claim 1; Preferably, 3-aminoindole and disubstituted chlorophosphine undergo Suzuki-Miyaura coupling reaction to prepare the multidentate nitrogen phosphine ligand represented by formula (1).

8. Use of the multidentate nitrogen phosphine ligand according to claim 1 or 2 or the multidentate nitrogen phosphine ligand prepared by the preparation method according to any one of claims 3 to 7 in the hydroformylation reaction of olefins; The olefin is a C2-C12 monoolefin, preferably propylene, 1-butene, pentene, octene, heptene or n-dodecene.

9. A method for the hydroformylation of olefins, wherein: The reaction formula of the hydroformylation reaction is as follows: Among them, the It is a C2-C12 monoolefin, preferably propylene, 1-butene, pentene, octene, heptene, and n-dodecene; M represents a transition metal catalyst, and L represents a multidentate nitrogen phosphine ligand, which is a multidentate nitrogen phosphine ligand as described in claim 1 or 2 or a multidentate nitrogen phosphine ligand prepared by the preparation method as described in any one of claims 3 to 7.

10. The method for hydroformylation of olefins according to claim 9, wherein: The transition metal catalyst is selected from one or more of rhodium acetate, rhodium octanoate, rhodium acetylacetonate, rhodium acetylacetonate carbonyl rhodium, dicarbonyl acetylacetonate rhodium, triphenylphosphine acetylacetonate rhodium, cobalt acetate, cobalt octanoate, cobalt acetylacetonate, cobalt acetylacetonate carbonyl cobalt, triphenylphosphine acetylacetonate cobalt; Preferably, the amount of the transition metal catalyst used is 0.02-0.2%, preferably 0.05-0.2%, based on the molar amount of the olefin calculated as metal atoms; Preferably, the amount of the multidentate nitrogen phosphine ligand is 5-50 times, preferably 10-30 times, the molar amount of the metal atom in the transition metal catalyst; Preferably, the hydroformylation reaction is carried out in a solvent, wherein the solvent is selected from at least one of tetrahydrofuran, 1,4-dioxane, benzene and toluene, more preferably 1,4-dioxane and / or toluene; preferably, the amount of the solvent added is 10-100 times the molar amount of the olefin, more preferably 10-30 times; Preferably, the reaction temperature of the hydroformylation reaction is 90-200°C, preferably 100-180°C, and the reaction time is 1-15h, preferably 3-12h; Preferably, the reaction pressure of the hydroformylation reaction is 1.0-20 MPaG, preferably 1.0-4.0 MPaG, and the reaction pressure is regulated by synthesis gas, and the CO / H2 molar ratio in the synthesis gas is 1:0.5-1.5, preferably 1:1.

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