A process for the preparation of 1,6-hexanedial

Abstract

The application provides a preparation method of 1,6-hexanedial, comprising the following steps: carrying out a polymerization reaction on a bidentate phosphine ligand monomer and a monomer containing a vinyl group, obtaining an organic phosphine ligand copolymer after the polymerization reaction; under the protection of mixed gas of H2 and CO, reacting the organic phosphine ligand copolymer and a metal rhodium precursor at 60-120 DEG C for 1-4 h, obtaining a catalyst; adding 1,3-butadiene into the catalyst to carry out a hydroformylation reaction, and obtaining 1,6-hexanedial after the reaction. The catalyst provided by the application can realize heterogeneous catalysis of 1,3-butadiene hydroformylation reaction, effectively improve the selectivity of 1,6-hexanedial, and the catalyst is easy to separate from the reaction product, so that the problems of catalyst recycling and environmental pollution can be effectively solved.

Description

Technical Field

[0001] This invention relates to a method for preparing 1,6-hexanedialdehyde, and relates to the field of petrochemical technology. Background Technology

[0002] The hydroformylation of olefins to produce aldehydes is an important industrial method for synthesizing aldehydes, efficiently converting inexpensive and readily available olefins into higher value-added fine chemicals. Therefore, hydroformylation has become one of the largest-scale catalytic processes. However, to date, most olefins used in industrial production are non-conjugated olefins. The hydroformylation of conjugated olefins to produce poly(aldehydes) remains challenging, mainly due to the numerous byproducts and poor regioselectivity. Taking the simplest conjugated olefin, 1,3-butadiene, as an example, the hydroformylation of 1,3-butadiene can occur via various pathways, including 1,4-addition carbonylation, 1,2-addition carbonylation, C=C double bond isomerization, reduction, and isomerization-reduction. These pathways are characterized by slow reaction rates, poor regioselectivity, and the simultaneous formation of more than a dozen isomerization products and byproducts.

[0003] Rhodium is the most widely used and most reactive metal in the research and development of the hydroformylation reaction of 1,3-butadiene. However, the selectivity of the Rh-based catalytic system for the synthesis of 1,6-hexanedialdehyde from 1,3-butadiene hydroformylation is only about 40%, far below the requirements for practical industrial applications. Furthermore, rhodium is a precious metal, making its precursor compounds very expensive. Currently developed catalysts are homogeneous, and the precious rhodium catalyst cannot be recovered after the reaction, increasing both the reaction cost and environmental pressure. Therefore, how to solve the problems of low selectivity and unrecoverable catalysts in the preparation of 1,6-hexanedialdehyde from 1,3-butadiene hydroformylation has received increasing attention. Summary of the Invention

[0004] This invention provides a method for preparing 1,6-hexanedialdehyde, which solves the problems of poor selectivity and inability to recover the catalyst.

[0005] This invention provides a method for preparing 1,6-hexanedialdehyde, the method comprising the following steps:

[0006] A bidentate phosphine ligand monomer is polymerized with a vinyl-containing monomer to obtain an organophosphine ligand copolymer after the polymerization reaction. Under the protection of a mixture of H2 and CO, the organophosphine ligand copolymer and a rhodium precursor are reacted at 60-120°C for 1-4 h to prepare a catalyst. 1,3-Butadiene is added to the catalyst for hydroformylation to obtain 1,6-hexanedialdehyde after the reaction.

[0007] The bidentate phosphine ligand monomer has the structure shown in Formula 1:

[0008]

[0009] In Equation 1, R1 and R2 are independently selected from... One of them, "." indicates the connection position of R1, R2 and oxygen atom; the monomer containing vinyl group is selected from One of them.

[0010] This invention provides a method for preparing 1,6-hexanedialdehyde, which utilizes an organophosphorus ligand copolymer as a support and ligand to form a single-site coordination structure for catalysis, thereby achieving heterogeneous catalysis of the hydroformylation reaction of 1,3-butadiene. Figure 1 This is a schematic flowchart of a preparation method provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the method specifically includes the following steps:

[0011] Step 1: The bidentate phosphine ligand monomer is polymerized with a vinyl-containing monomer. After the polymerization reaction is complete, an organophosphine ligand copolymer is obtained. The reaction process is shown below:

[0012]

[0013] Step 1-1: Compound 1 was prepared according to Chinese Patent No. CN 113004326A. Compound 1 was placed in a reaction vessel, and an ethylene reagent, catalyst and solvent were added. The mixture was refluxed overnight under nitrogen protection, cooled to room temperature, and the solvent was removed by vacuum distillation. The mixture was purified by column chromatography to obtain compound 2.

[0014] The ethyleneizing agent is selected from One of the following; the catalyst is selected from one of tetra(triphenylphosphine)palladium, PdCl2(dppf), and PdCl2(PPh3)2; the solvent is selected from one or more of toluene, tetrahydrofuran, and 1,4-dioxane.

[0015] Steps 1-2: Under nitrogen protection, add phosphine chloride compounds (R1-Cl and / or R2-Cl) and solvent to the reactor, and cool to 0°C. Separately, dissolve compound 2 and triethylamine in the solvent, and add the mixed solution of compound 2 and triethylamine dropwise to the reactor at 0°C. Allow the reactor to naturally warm to room temperature, quench the reaction with water, extract with ethyl acetate, dry the organic phase with anhydrous sodium sulfate, and separate by column chromatography to obtain the compound shown in Formula 1; wherein the solvent is selected from one or more of tetrahydrofuran, toluene, and N,N-dimethylformamide.

[0016] Steps 1-3: Add the compound shown in Formula 1 to the reactor, along with a monomer containing vinyl groups, AIBN, and a solvent. Perform the polymerization reaction under nitrogen protection. After the polymerization reaction is completed, cool to room temperature, add methanol to precipitate, filter, wash, and vacuum dry to obtain the organophosphine ligand polymer shown in Formula 2.

[0017] To further improve the selectivity of 1,6-hexanedialdehyde, R1 and R2 are independently selected from... One of them, wherein the vinyl-containing monomer is selected from One of them.

[0018] The molar ratio of the bidentate phosphine ligand monomer to the vinyl-containing monomer is 1:(1-10); the polymerization reaction is carried out at a temperature of 60-100℃ for 2-6 hours; and the solvent is selected from one or more of tetrahydrofuran, 2-methyltetrahydrofuran, and toluene.

[0019] The prepared organophosphorus ligand compound can be represented by the structure shown in Formula 2, wherein the molecular weight of the organophosphorus ligand copolymer is 70,000-100,000 g / mol, 35 ≤ m ≤ 55, 35 ≤ n ≤ 55, and m:n = 1:(1-10).

[0020] Step 2: Under the protection of a mixture of H2 and CO, the organophosphine ligand copolymer and the rhodium precursor are reacted at 60-120℃ for 1-4 hours to prepare the catalyst;

[0021] The rhodium precursor can be a conventional material in the art, specifically selected from one or more of Rh(CO)2(acac), Rh(AcO)2, RhCl3, Rh(NO3)3, RhH(CO)(PPh3)3, [Rh(CO)2Cl]2, RhH(CO)(PPh3)3, [Rh2(m-Cl)2(cod)2], and [Rh(cod)2]BF4. Further, the rhodium precursor is Rh(CO)2(acac).

[0022] The organophosphorus ligand polymer and the rhodium precursor prepared by the above method are added to a reaction vessel and a certain amount of solvent is added for dispersion. The mass ratio of the rhodium precursor to the organophosphorus ligand copolymer is (1:1) to (1:50), and further, the mass ratio of the rhodium precursor to the organophosphorus ligand copolymer is (1:5) to (1:20).

[0023] The solvent is selected from one or more of n-hexane, cyclohexane, benzene, toluene, xylene, tetrahydrofuran, and dioxane, and further, the solvent is selected from one or more of n-hexane, tetrahydrofuran, and toluene.

[0024] The reactor can then be sealed, and a mixture of H2 and CO gas is continuously introduced. The reaction is carried out at 60-120℃ for 1-4 hours to prepare the catalyst. The mixed gas is used to protect the catalyst. The pressure of the H2 and CO mixture is 1-10 MPa, and the volume ratio of H2 to CO is (1:10)-(10:1). Further, the pressure of the mixed gas is 2-5 MPa, and the volume ratio of H2 to CO is (1:5)-(1:1). The catalyst can be obtained by controlling the temperature and stirring the reaction for a certain period of time.

[0025] Step 3: Add 1,3-butadiene to the catalyst to carry out a hydroformylation reaction, and after the reaction is completed, 1,6-hexanedialdehyde is prepared.

[0026] 1,3-Butadiene is added to the catalyst. Specifically, 1,3-Butadiene can be dissolved in a solvent to prepare a 1,3-Butadiene solution. The molar ratio of the rhodium precursor to the 1,3-Butadiene is (1:50) to (1:50000). Further, the molar ratio of the rhodium precursor to the 1,3-Butadiene is (1:200) to (1:1000). The solvent can be one or more of hexane, toluene, and tetrahydrofuran. Further, the solvent is one or more of hexane and toluene. The concentration of the 1,3-Butadiene solution is 0.1-10 mol / L. Further, the concentration of the 1,3-Butadiene solution is 0.5-3 mol / L.

[0027] The hydroformylation reaction is then carried out at a controlled temperature of 50-150℃, and the reaction time is generally 1-24 hours. After the reaction system is cooled to room temperature, the unreacted gas is released to obtain 1,6-hexanedialdehyde. Further, the reaction temperature is controlled at 60-120℃ and the reaction time is 5-15 hours.

[0028] The conversion rate of 1,3-butadiene was greater than or equal to 90%, and the selectivity of 1,6-hexanedialdehyde was greater than or equal to 49%, as determined by gas chromatography with internal standard method.

[0029] By using the organic ligand copolymer provided by this invention as a support and ligand, a single-point coordination structure catalysis is formed to achieve heterogeneous catalysis of 1,3-butadiene hydroformylation reaction. At the same time, the selectivity of 1,6-hexanedialdehyde can be effectively improved, and the catalyst can be easily separated from the reaction products, which can effectively solve the problems of catalyst recycling and environmental pollution. Attached Figure Description

[0030] Figure 1 This is a schematic flowchart of a preparation method provided in an embodiment of the present invention;

[0031] Figure 2The 1H NMR spectrum of compound 2 during the preparation of the organophosphine ligand copolymer in Example 1;

[0032] Figure 3 The 1H NMR spectrum of compound 3 during the preparation of the organophosphine ligand copolymer in Example 1;

[0033] Figure 4 The NMR spectrum of compound 3 during the preparation of the organophosphine ligand copolymer in Example 1 is shown.

[0034] Figure 5 The 1H NMR spectrum of organophosphine ligand copolymer L1 in Example 1;

[0035] Figure 6 The NMR spectrum of organophosphine ligand copolymer L1 in Example 1 is shown.

[0036] Figure 7 The NMR spectrum of organophosphine ligand copolymer L2 in Example 8 is shown.

[0037] Figure 8 The NMR spectrum of organophosphine ligand copolymer L3 in Example 9 is shown. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] Example 1

[0040] Step 1: Preparation of organophosphine ligand copolymer L1:

[0041] Step 1-1: Compound 1 was prepared using 1,8-dihydroxyanthraquinone as a raw material, according to CN113004326A.

[0042] Steps 1-2: Add 5g of compound 1 to the reactor, along with 100ml of toluene, 12g of vinyltri-n-butyltin, and 0.73g of tetra(triphenylphosphine)palladium. Reflux under nitrogen protection overnight. After the reaction is complete, cool to room temperature, remove the solvent by vacuum distillation, and purify by column chromatography with petroleum ether:ethyl acetate = 2:1 as the eluent. Compound 2 is obtained. The NMR data of compound 2 are shown below, and the H-spectrum is shown in Figure 2.

[0043] 1H NMR (400MHz, DMSO) δ9.39(s,1H),7.16(dt,J=11.2,8.2Hz,2H), 6.60(d,J=8.5Hz,1H),5.56(d,J=1.4Hz,1H), 5.18(dd,J=11.0,1.4Hz,1H), 5.10(d,J=1.7Hz,1H),1.51(s,2H).

[0044] Steps 1-3: Take 1.27g of Add the compound to the reactor, add 6 ml of ultra-dry tetrahydrofuran under nitrogen protection, and cool to 0°C. Separately, dissolve 400 mg of compound 2 and 418 mg of triethylamine in 2 ml of ultra-dry tetrahydrofuran, and add this mixture dropwise to the reactor at 0°C. Allow the mixture to naturally warm to room temperature and react for 1 h. Quench with 20 ml of water, extract with 20 ml of ethyl acetate, dry the organic phase with anhydrous sodium sulfate, and separate by column chromatography to obtain compound 3. The NMR data of compound 3 are as follows, and the H-ray and phosphine spectra are as follows. Figure 3 , Figure 4 As shown;

[0045] 1 H NMR (400MHz, CDCl3) δ7.22 (d, J = 8.5 Hz, 2H), 7.14 (dd, J = 17.4, 11.0Hz,2H),7.03(d,J=3.8Hz,5H),6.97(d,J=8.5Hz,2H),6.92(d,J=8.3Hz,5H),5.61(dd,J=17.4,1.2Hz,2H),5.42(s,1H),5.34(dd,J=11.0,1.2Hz, 2H), 5.15 (s, 0H), 2.31 (d, J = 7.2Hz, 12H), 2.21 (d, J = 3.6Hz, 12H), 1.67 (q, J = 9.1Hz, 4H).

[0046] Steps 1-4: Add 400 mg of compound 3 to the reactor, along with 500 mg of styrene, 45 mg of AIBN, and 9 ml of ultra-dry tetrahydrofuran. React at 100 °C for 4 h under nitrogen protection. After the reaction, cool to room temperature, add 20 ml of methanol to precipitate, filter, wash with methanol, and vacuum dry to obtain organophosphine ligand copolymer L1. Its 1H NMR and phosphine NMR spectra are shown below. Figure 5 , 6 As shown in the figure below, the reaction process is as follows:

[0047]

[0048] The organophosphine ligand copolymer L1 has a molecular weight of 85,000 g / mol, m = 40, n = 50, and m:n = 1:1.25.

[0049] Step 2: In a glove box, weigh 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2, add them to an autoclave, then add 3 ml of toluene, seal the autoclave, and introduce a mixture of H2 and CO at a pressure of 2 MPa and a volume ratio of 1:1. Stir at 80 °C for 2 h to prepare the catalyst.

[0050] Step 3: Cool down, add 1 ml of 3 mol / L 1,3-butadiene toluene solution, pressurize to 4 MPa, and stir the reaction at 60 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0051] The conversion rate of 1,3-butadiene was 95.3% and the selectivity of 1,6-hexanedialdehyde was 51.5%, as determined by gas chromatography with internal standard method.

[0052] Example 2

[0053] In a glove box, 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0054] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0055] The conversion rate of 1,3-butadiene was 99.2% and the selectivity of 1,6-hexanedialdehyde was 49.2%, as determined by gas chromatography with internal standard method.

[0056] Example 3

[0057] In a glove box, 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0058] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 100 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0059] The conversion rate of 1,3-butadiene was 99.8% and the selectivity of 1,6-hexanedialdehyde was 52.6%, as determined by gas chromatography with internal standard method.

[0060] Example 4

[0061] In a glove box, 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0062] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The mixture was stirred at 2 MPa and 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0063] The conversion rate of 1,3-butadiene was 92.8% and the selectivity of 1,6-hexanedialdehyde was 55.8%, as determined by gas chromatography with internal standard method.

[0064] Example 5

[0065] In a glove box, 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a volume ratio of 1:1 and a pressure of 2 MPa was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0066] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 6 MPa, and the mixture was stirred at 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0067] The conversion rate of 1,3-butadiene was 99.8% and the selectivity of 1,6-hexanedialdehyde was 57.9%, as determined by gas chromatography with internal standard method.

[0068] Example 6

[0069] In a glove box, 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0070] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 8 h to prepare 1,6-hexanedialdehyde.

[0071] The conversion rate of 1,3-butadiene was 91.5% and the selectivity of 1,6-hexanedialdehyde was 56.5%, as determined by gas chromatography with internal standard method.

[0072] Example 7

[0073] In a glove box, 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0074] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 15 h to prepare 1,6-hexanedialdehyde.

[0075] The conversion rate of 1,3-butadiene was 99.7% and the selectivity of 1,6-hexanedialdehyde was 49.0%, as determined by gas chromatography with internal standard method.

[0076] Example 8

[0077] The preparation method of organophosphine ligand copolymer L2 can be referred to Example 1, with the difference being:

[0078] 300 mg of compound 3 was added to a reactor, along with 1.22 g of tris(4-vinylphenyl)phosphine, 35 mg of AIBN, and 15 ml of ultra-dry tetrahydrofuran. The reaction was carried out at 100 °C for 5 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, precipitated with 20 ml of methanol, filtered, washed with methanol, and dried under vacuum to obtain organophosphine ligand copolymer L2. Its phosphine spectrum is shown below. Figure 7 As shown, the reaction process involved is as follows:

[0079]

[0080] The organophosphine ligand copolymer L2 has a molecular weight of 91000 g / mol, m = 36, n = 52, and m:n = 1:1.44.

[0081] In a glove box, 20 mg of organophosphorus ligand copolymer L2 and 1 mg of rhodium precursor Rh(acac)(CO)2 were added to a high-pressure reactor, followed by 3 ml of toluene. The high-pressure reactor was sealed, and a mixture of H2 and CO at a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0082] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0083] The conversion rate of 1,3-butadiene was 99.5% and the selectivity of 1,6-hexanedialdehyde was 53.4%, as determined by gas chromatography with internal standard method.

[0084] Example 9

[0085] The preparation method of organophosphine ligand copolymer L3 can be referenced from L1, the difference being that R1 and R2 in compound 3 are... The organophosphine ligand copolymer L4 has a molecular weight of 81000 g / mol, m = 40, n = 48, and m:n = 1:1.2. Its phosphine spectrum is as follows: Figure 8 As shown.

[0086] In a glove box, 9.3 mg of organophosphorus ligand copolymer L3 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0087] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0088] The conversion rate of 1,3-butadiene was 99.6% and the selectivity of 1,6-hexanedialdehyde was 50.9%, as determined by gas chromatography with internal standard method.

[0089] Example 10

[0090] The preparation method of organophosphine ligand copolymer L4 can be referenced from L1, the difference being that R1 and R2 in compound 3 are... In step 4, the vinyl monomer is tris(4-vinylphenyl)phosphine, and the molecular weight of organophosphine ligand copolymer L4 is 88000 g / mol, m = 45, n = 50, and m:n = 1:1.11.

[0091] In a glove box, 20 mg of organophosphorus ligand copolymer L4 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0092] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0093] The conversion rate of 1,3-butadiene was 95.5% and the selectivity of 1,6-hexanedialdehyde was 51.8%, as determined by gas chromatography with internal standard method.

[0094] Example 11

[0095] The preparation method of organophosphine ligand copolymer L5 can be referenced from L1, the difference being that R1 in compound 3 is... R2 is The organophosphine ligand copolymer L5 has a molecular weight of 95,000 g / mol, m = 38, n = 52, and m:n = 1:1.37.

[0096] In a glove box, 9.2 mg of organophosphorus ligand copolymer L5 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0097] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0098] The conversion rate of 1,3-butadiene was 90.8% and the selectivity of 1,6-hexanedialdehyde was 55.6%, as determined by gas chromatography with internal standard method.

[0099] Example 12

[0100] The preparation method of organophosphine ligand copolymer L6 can be referenced from L1, the difference being that R1 in compound 3 is... R2 is In step 4, the vinyl monomer is tris(4-vinylphenyl)phosphine, and the molecular weight of organophosphine ligand copolymer L6 is 98000 g / mol, m = 50, n = 54, and m:n = 1:1.08.

[0101] In a glove box, 9.2 mg of organophosphorus ligand copolymer L6 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0102] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene-toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 12 h to prepare 1,6-hexanedialdehyde.

[0103] The conversion rate of 1,3-butadiene was 92.2% and the selectivity of 1,6-hexanedialdehyde was 56.9%, as determined by gas chromatography with internal standard method.

[0104] To provide a clearer understanding of the present invention, the catalysts used in Examples 1-12 and the reaction process parameters are listed in Tables 1-2:

[0105] Table 1. Organophosphine ligand copolymers used in Examples 1-12.

[0106]

[0107] Table 2 shows the reaction parameters provided in Examples 1-12.

[0108]

[0109] As shown in Table 2, the organophosphorus ligand copolymers provided by the present invention can effectively catalyze the hydroformylation reaction of 1,3-butadiene, and the conversion rate of 1,3-butadiene is greater than or equal to 90%, and the selectivity of 1,6-hexanedialdehyde is greater than or equal to 49%.

[0110] Example 13

[0111] In a glove box, 8.5 mg of organophosphorus ligand copolymer L1 and 1 mg of rhodium precursor Rh(acac)(CO)2 were weighed and added to a high-pressure reactor. Then, 3 ml of toluene was added, the high-pressure reactor was sealed, and a mixture of H2 and CO with a pressure of 2 MPa and a volume ratio of 1:1 was introduced. The mixture was stirred at 80 °C for 2 h to prepare the catalyst.

[0112] The mixture was cooled, and 1 ml of a 3 mol / L 1,3-butadiene toluene solution was added. The pressure was increased to 4 MPa, and the mixture was stirred at 80 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature, the unreacted gas was released, and the liquid product was taken out. The conversion rate of 1,3-butadiene was 99.2% and the selectivity of 1,6-hexanedialdehyde was 53.2% as determined by gas chromatography with internal standard method.

[0113] After the reaction was complete, the solvent, reaction products, and unreacted raw materials were removed by vacuum distillation under nitrogen protection. The remaining residue was transferred to the reactor. The above operation was repeated, adding the same amounts of solvent, 1,3-butadiene, and syngas. The reaction was carried out at 80°C with stirring for 12 hours. After the reaction was complete, the products were analyzed. The conversion rate of 1,3-butadiene was 99.0%, and the selectivity for 1,6-hexanedialdehyde was 53.1%.

[0114] Repeat the above operation for the second cycle. After the reaction is complete, analyze the product. The conversion rate of 1,3-butadiene is 98.5%, and the selectivity of 1,6-hexanedialdehyde is 52.3%.

[0115] In the third cycle, after the reaction was completed, the products were analyzed. The conversion rate of 1,3-butadiene was 97.8%, and the selectivity of 1,6-hexanedialdehyde was 51.8%.

[0116] In the fourth cycle, after the reaction was completed, the product was analyzed. The conversion rate of 1,3-butadiene was 96.8%, and the selectivity of 1,6-hexanedialdehyde was 51.4%.

[0117] After the fifth cycle, the product was analyzed after the reaction was completed. The conversion rate of 1,3-butadiene was 95.6%, and the selectivity of 1,6-hexanedialdehyde was 50.7%.

[0118] The rhodium-based organic polymer catalyst provided by this invention enables heterogeneous catalysis of the hydroformylation reaction of 1,3-butadiene, thereby effectively solving problems such as catalyst recovery, recycling, and pollution.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for the preparation of 1,6-hexanedial, characterized in that, The method comprises the following steps: The bidentate phosphine ligand monomer and the monomer containing vinyl are subjected to polymerization reaction, and the organic phosphine ligand copolymer is obtained after the polymerization reaction; under the protection of H2 and CO mixed gas, the organic phosphine ligand copolymer and the metal rhodium precursor are reacted at 60-120 DEG C for 1-4 h to prepare the catalyst; 1,3-butadiene is added to the catalyst to perform hydroformylation reaction, and 1,6-hexanedial is prepared after the reaction. The bidentate phosphine ligand monomer has the structure shown in formula 1: In formula 1, R1 and R2 are independently selected from The molar ratio of the bidentate phosphine ligand monomer to the monomer containing vinyl is 1: (1-10); The polymerization reaction temperature is 100 DEG C, and the time is 2-6 h.

2. The method of claim 1, wherein, The R1 and R2 are independently selected from 3. The method of claim 1, wherein, The metal rhodium precursor is selected from one or more of Rh (CO) 2 (acac), Rh (AcO) 2, RhCl3, Rh (NO3) 3, RhH (CO) (PPh3) 3, [Rh (CO) 2Cl] 2, [Rh2 (m-Cl) 2 (cod) 2], [Rh (cod) 2] BF4.

4. The method according to claim 1 or 3, characterized in that, The mass ratio of the metal rhodium precursor to the organic phosphine ligand copolymer is (1: 1)-(1: 50).

5. The method according to claim 1 or 3, characterized in that, The mass ratio of the metal rhodium precursor to the organic phosphine ligand copolymer is (1: 5)-(1: 20).

6. The method according to any one of claims 1 to 3, characterized in that, The pressure of the H2 and CO mixed gas is 1-10 MPa, and the volume ratio of H2 to CO is (1:10)-(10:1).

7. The method according to any one of claims 1 to 3, characterized in that, The molar ratio of the metal rhodium precursor to the 1,3-butadiene is (1: 50)-(1: 50000).

8. The method according to any one of claims 1 to 3, characterized in that, The hydroformylation reaction temperature is 50-150 DEG C, and the time is 1-24 h.

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