A process for the preparation of polyadipates from butadiene

Abstract

The application discloses a method for preparing polyadipate from butadiene and belongs to the field of polymer synthesis. 1,3-butadiene, carbon monoxide and polyhydric alcohol are used as polymerization monomers, a palladium compound and a phosphine ligand are used as a catalyst, and acid is used as an additive to perform a hydrocarbonylation esterification polymerization reaction in an organic solvent such as toluene, so that a polyadipate product is obtained with high selectivity. When the ratio of polyhydric alcohol to butadiene is increased, polyadipate polyhydric alcohol with a chain end of a hydroxyl group can be obtained in a controllable manner, and the obtained product polyadipate can be applied to the field of polymer materials such as plastics or textiles.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis, specifically relating to a method for preparing polyadipate from butadiene. Background Technology

[0002] Polyadipate has a wide range of applications in the materials field, such as poly(butylene adipate-succinate) (PBAT) as a raw material for biodegradable plastic bags; polyadipate polyols can be block-addition polymerized with isocyanates to obtain polyurethane, which is used in the synthesis of polyurethane resins, polyurethane solutions or polyurethane elastomers.

[0003] Poly(adipate) esters are typically obtained through the polycondensation reaction of adipic acid with a glycol monomers. Adipic acid is synthesized from the petrochemical feedstock benzene. The specific synthetic route is as follows: Figure 8 As shown, benzene is hydrogenated and reduced to cyclohexane, which is then oxidized to cyclohexanol and cyclohexanone (KA oil). KA oil is then oxidized with nitric acid to obtain adipic acid. Adipic acid then undergoes esterification, flash evaporation, and polycondensation with diols such as 1,4-butanediol to obtain polyadipate, as disclosed in the existing patent (CN 107987265 A, A continuous preparation method for polyester polyols). This synthetic route has significant drawbacks: the route for synthesizing adipic acid from benzene is lengthy, involves continuous reduction and oxidation processes, is uneconomical, and generates a large amount of waste. Furthermore, the esterification and polycondensation reactions are reversible, requiring depressurization during the polycondensation process to remove small molecules and shift the chemical equilibrium towards polyester.

[0004] Butadiene, as one of the basic raw materials of petrochemicals known as "trienes, benzenes, and styrene," has a wide range of applications in polymer synthesis, currently mainly concentrated in the rubber industry. Examples include butadiene polymerization to obtain cis-butadiene rubber, butadiene-styrene copolymerization to obtain styrene-butadiene rubber, butadiene-styrene block copolymerization to obtain SBS rubber, butadiene-acrylonitrile copolymerization to obtain nitrile rubber, and butadiene-acrylonitrile-styrene copolymerization to obtain ABS rubber.

[0005] Therefore, developing novel direct synthesis methods for polyadipate esters from butadiene, a basic raw material in petrochemicals, has great scientific and economic significance. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a method for preparing polyadipate from butadiene. This invention uses 1,3-butadiene, carbon monoxide, and a polyol as monomers, palladium compounds and phosphine ligands as catalysts, and sulfonic acid as an additive. A hydrocarbonylation esterification polymerization reaction is carried out in an organic solvent such as toluene to obtain the polyadipate product with high selectivity. Furthermore, by increasing the ratio of polyol to butadiene, polyadipate polyols with hydroxyl groups at the chain ends can be controllably obtained.

[0007]

[0008] The objective of this invention can be achieved through the following methods:

[0009] This invention provides a method for preparing polyadipate from butadiene, comprising the following steps:

[0010] S1. Mix palladium catalyst, phosphine ligand, acid additive, diol substrate, 1,3-butadiene, and organic solvent, introduce carbon monoxide, heat to react, and obtain reaction solution after the reaction is completed.

[0011] S2. Dilute the reaction solution with a diluent and then drop it into a highly polar solvent to settle. Dry the resulting precipitate to obtain poly(adipate glycol) ester.

[0012] The reaction equation is as follows:

[0013]

[0014] This invention relates to a method for directly preparing polyadipate from butadiene.

[0015] In one embodiment of the present invention, in step S1, the palladium catalyst includes one or more of Pd(TFA)2, Pd2(dba)3, Pd(dba)2, Pd2(dba)3, Pd2(dba)3·CHCl3, PdCl2, PdCl2(CH3CN)2, PdBr2, PdI2, or Pd(OAc)2. A preferred palladium catalyst is Pd(TFA)2.

[0016] In one embodiment of the present invention, in step S1, the phosphine ligand includes one or more of triphenylphosphine, tri-tert-butylphosphine, 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene), bis(2-diphenylphosphine) ether, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine), DPPE, 1,3-bis(diphenylphosphine)ethane, 1,3-bis(diphenylphosphine)propane, 1,3-bis(diphenylphosphinebutane), 1,3-bis(diphenylphosphine)pentane, 1,2-bis(diphenylphosphine)benzene, 1,2-bis((di-tert-butylphosphine)methyl)benzene, or 1,2-bis((diphenyl)methyl)benzene. A preferred phosphine ligand is 1,2-bis((di-tert-butylphosphine)methyl)benzene.

[0017] In one embodiment of the present invention, in step S1, the acid additive includes one or more of hydrogen chloride, sulfuric acid, phosphoric acid, trifluoroacetic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid. Dodecylbenzenesulfonic acid is preferred.

[0018] In one embodiment of the present invention, in step S1, the organic solvent includes one or more of toluene, xylene, trimethylbenzene, ethylbenzene, fluorobenzene, chlorobenzene, 1,4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, 1,2-dichloroethane, acetonitrile, N,N-dimethylformamide, and N,N-dimethylacetamide. Toluene is preferred as the organic solvent.

[0019] As one embodiment of the present invention, in step S1, the diol substrate includes one or more diols of two to twenty carbons. Diols with two to twenty carbon atoms include one of the following: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 1,16-hexadecanediol, 1,20-eicosenediol, diethylene glycol, triethylene glycol, 1,4-cyclohexyldiethanol, neopentyl glycol, cyclohexanediol, isosorbide dimethyl terephthalate, isophenylenediol, furanyldiethanol, polyethylene glycol, polypropylene glycol, and polytetrahydrofuran.

[0020] As one embodiment of the present invention, the molar amounts of each raw material in step S1 are as follows:

[0021] The ratio of 1,3-butadiene to diol substrate is 0.5–1.5:1;

[0022] The ratio of 1,3-butadiene to palladium catalyst is 100,000 to 10:1;

[0023] The ratio of phosphine ligand to palladium catalyst is 10 to 1:1;

[0024] The ratio of acid additive to palladium catalyst is 100 to 1:1.

[0025] In one embodiment of the present invention, in step S1, the addition of 1,3-butadiene is either by adding a solution of 1,3-butadiene or by introducing 1,3-butadiene gas. The 1,3-butadiene solution is obtained by first adding 1,3-butadiene to a solvent, and the concentration of 1,3-butadiene is 1% to 15% by mass.

[0026] In one embodiment of the present invention, in step S1, the pressure of carbon monoxide is 1 to 100 bar.

[0027] In one embodiment of the present invention, in step S1, the heating reaction is divided into two stages. The first stage heating temperature is 110-130℃, and the holding time is 4-8 hours; the second stage heating temperature is 140-160℃, and the holding time is 22-26 hours. The heating time from the first stage heating to the second stage heating is 0.5-4 hours. The product from the first stage heating has a low molecular weight (number average molecular weight not exceeding 3000), while the second stage heating allows the product to further polymerize, achieving a higher molecular weight (number average molecular weight up to approximately 12000).

[0028] This invention relates to the synthesis of polyesters. In polymer synthesis, the viscosity of the reaction system increases with increasing molecular weight, thus the mass transfer process in solution is significantly slower compared to the synthesis of smaller molecules. Extending the heating time without using a two-stage heating method does not increase the molecular weight. This invention employs a staged heating method, which accelerates the mass transfer process in solution, speeds up the polymerization process, and leads to an increase in molecular weight. Figure 9 As shown, during the first stage of heating, the main product is oligomeric polyester, which can be reacted into high molecular weight polyadipate after further heating.

[0029] In one embodiment of the present invention, in step S2, the diluent is one or more of dichloromethane and tetrahydrofuran. The highly polar solvent is one or more of methanol and ethanol.

[0030] In one embodiment of the present invention, in step S2, the drying temperature is 40-50°C, preferably 45°C. The resulting polyadipate glycol ester is a white powder.

[0031] This invention provides a method for preparing polyester from dienes, comprising the following steps:

[0032] A1. Mix palladium catalyst, phosphine ligand, acid additive, polyol substrate, diene and organic solvent, introduce carbon monoxide, heat to react, and obtain reaction solution after the reaction is completed.

[0033] A2. Dilute the reaction solution with a diluent, add it dropwise into a highly polar solvent to settle, and dry the resulting precipitate to obtain polyadipate.

[0034] The reaction equation is as follows:

[0035]

[0036] In one embodiment of the present invention, in step A1, the polyol substrate includes one or more polyols with two to twenty carbon atoms. Polyols with two to twenty carbon atoms include one of diols, triglycerides, trimethylolethane, trimethylolpropane, benzotriol, and pentaerythritol. Diols include one or more diols with two to twenty carbon atoms. Diols with two to twenty carbon atoms include one of the following: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 1,16-hexadecanediol, 1,20-eicosenediol, diethylene glycol, triethylene glycol, 1,4-cyclohexyldiethanol, neopentyl glycol, cyclohexanediol, isosorbide dimethyl terephthalate, isophenylenediol, furanyldiethanol, polyethylene glycol, polypropylene glycol, and polytetrahydrofuran.

[0037] In one embodiment of the present invention, in step A1, the diene includes one of 1,3-butadiene, pentadiene, isoprene, hexadiene, and norbornene.

[0038] The polyol substrate is a diol substrate, and the diene is 1,3-butadiene, to obtain polyadipate.

[0039] The selection of substances and parameters in the method for preparing polyester is the same as that in the method for preparing polyadipate. The preparation method of this invention is not limited to glycol monomers; triols and tetraols, among other polyols, can also be used to obtain cross-linked polyadipate polyols through this reaction. Other dienes, such as pentadiene, isoprene, hexadiene, and norbornene, can also be used to obtain corresponding polyesters through this method.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] This invention utilizes a method starting from 1,3-butadiene, a bulk raw material in the petrochemical industry, to synthesize polyadipate esters in one step via a hydrogen carbonylation esterification polymerization reaction with polyol monomers. This method boasts 100% atom economy, high reaction yield, excellent selectivity for linear adipic acid, and controllable polymer molecular weight. The resulting polyadipate ester can be applied in the fields of plastics and textiles, among other polymer materials. Attached Figure Description

[0042] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0043] Figure 1 This is a schematic diagram of the synthesis method of polyadipate;

[0044] Figure 2GPC diagram of polyhexyl adipate prepared in Example 1;

[0045] Figure 3 The polyhexanediol adipate prepared in Example 1 1 H NMR;

[0046] Figure 4 The polyhexanediol adipate prepared in Example 1 13 C NMR;

[0047] Figure 5 GPC diagram of poly(dodecyl adipate) glycol ester prepared in Example 2;

[0048] Figure 6 The poly(dodecyl adipate) diol ester prepared in Example 2 1 H NMR;

[0049] Figure 7 The poly(dodecyl adipate) diol ester prepared in Example 2 13 C NMR;

[0050] Figure 8 A route diagram for the synthesis of adipic acid from the petrochemical feedstock benzene;

[0051] Figure 9 This is a schematic diagram of the two-stage production process when heating from both ends. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following examples are implemented under the premise of the technical solution of the present invention, providing detailed implementation methods and specific operating procedures, which will help those skilled in the art to further understand the present invention. It should be noted that the scope of protection of the present invention is not limited to the following embodiments; any adjustments and improvements made under the concept of the present invention are all within the scope of protection of the present invention.

[0053] Example 1

[0054] This embodiment discloses a novel method for synthesizing polyadipate; the specific reaction equation is shown in [reference needed]. Figure 1 Poly(hexamethylene adipate) glycol ester is obtained from 1,3-butadiene, carbon monoxide and diol monomers under the action of catalysts and additives.

[0055] In a 45 mL autoclave, add Pd(TFA)₂ (16.6 mg, 0.05 mmol, molar ratio to 1,3-butadiene 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (39.5 mg, 0.1 mmol, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 0.2 mmol, 4 mol%), 1,6-hexanediol (591 mg, 5.0 mmol), and a toluene solution of 1,3-butadiene (butadiene mass fraction in toluene 13% w / w, mass of toluene solution 2.10 g, butadiene 5.0 mmol), and purge with 40 atm of carbon monoxide. The autoclave is incubated at 120 °C for 6 h, then the temperature is increased to 150 °C after 0.5 h, and the reaction is continued for 24 h. After cooling and depressurization, add 5 mL of dichloromethane to dissolve the solid after reaction, precipitate in 200 mL of methanol, decant the supernatant, collect the white precipitate, and dry it. 1.08 g of polyhexyl adipate, a white solid, was obtained, with a yield of 75%.

[0056] Using polystyrene as a standard, the number-average molecular weight, weight-average molecular weight, and dispersibility index determined by gel permeation chromatography (GPC) were 5352, 8548, and 1.60. (See attached image.) Figure 2 This is the GPC diagram of polyhexyl adipate.

[0057] The NMR characterization is as follows:

[0058] 1 H NMR (500MHz, CDCl3) δ = 4.06 (t, J = 6.6, 4H,), 2.32 (br s, J = 6.4, 4H), 1.82-1.54 (m, 8H), 1.47-1.26 (m, 4H).

[0059] 13 C NMR (126MHz, CDCl3) δ173.5,64.4,34.0,28.6,25.7,24.5.

[0060] Appendix Figure 3 Polyhexanediol adipate 1 H NMR, with Figure 4 Polyhexanediol adipate 13 C NMR.

[0061] Example 2

[0062] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (39.5 mg, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 4 mol%), 1,12-dodecanediol (1.01 g, 5.0 mmol), and a toluene solution of 1,3-butadiene (13% w / w, 2.10 g, 5.0 mmol) were added, followed by a flush with 40 atm of carbon monoxide. The autoclave was incubated at 120 °C for 6 h, then the temperature was increased to 150 °C after 0.5 h, and the reaction was continued for 24 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solid. The solid was then settled in 200 mL of methanol, the supernatant was decanted, and the white precipitate was collected and dried. 1.32 g of poly(dodecanediol adipate) solid was obtained, with a yield of 85%.

[0063] Using polystyrene as a standard, the number-average molecular weight, weight-average molecular weight, and dispersibility index determined by gel permeation chromatography (GPC) were 11867, 19520, and 1.64. (See attached image.) Figure 5 This is the GPC diagram of poly(dodecanediol adipate).

[0064] The NMR characterization is as follows:

[0065] 1 H NMR (500MHz, CDCl3) δ = 4.05 (t, J = 6.8, 4H), 2.32 (br s, 4H), 1.74-1.53 ​​(m, 8H), 1.29 (d, J = 18.6, 16H).

[0066] 13 C NMR (126MHz, CDCl3) δ173.5,64.6,34.0,29.6,29.6,29.4,28.7,26.0,24.5.

[0067] Appendix Figure 6 Poly(dodecanediol adipate) 1 H NMR, with Figure 7 Poly(dodecanediol adipate) 13 CNMR.

[0068] Example 3

[0069] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (39.5 mg, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 4 mol%), 1,12-dodecanediol (1.52 mg, 7.5 mmol), and a toluene solution of 1,3-butadiene (13% w / w, 2.10 g, 5.0 mmol) were added, followed by a flush with 40 atm of carbon monoxide. The autoclave was incubated at 120 °C for 6 h, then the temperature was increased to 150 °C after 0.5 h, and the reaction was continued for 24 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solid. The solid was then settled in 200 mL of methanol, the supernatant was decanted, and the white precipitate was collected and dried. 1.76 g of poly(dodecanediol adipate) diol, a white solid, was obtained, with a yield of 85%.

[0070] Using polystyrene as a standard, the number-average molecular weight was 3833, the weight-average molecular weight was 5316, and the dispersibility index was 1.39, as determined by gel permeation chromatography (GPC).

[0071] The NMR characterization is as follows:

[0072] 1 H NMR (500MHz, CDCl3) δ = 4.06 (t, J = 6.6, 4H,), 2.32 (br s, J = 6.4, 4H), 1.82-1.54 (m, 8H), 3.64 (t, J = 6.6, H, CH2OH), 1.47-1.26 (m, 4H).

[0073] 13 C NMR (126MHz, CDCl3) δ173.5, 64.4, 63.1 (CH2OH), 34.0, 28.6, 25.7, 24.5.

[0074] Example 4

[0075] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (39.5 mg, 2 mol%), p-toluenesulfonic acid (38.0 mg, 4 mol%), 1,12-dodecanediol (1.01 g, 5.0 mmol), and a toluene solution of 1,3-butadiene (13% w / w, 2.10 g, 5.0 mmol) were added, followed by a flush with 40 atm of carbon monoxide. The autoclave was incubated at 120 °C for 6 h, then the temperature was increased to 150 °C after 0.5 h, and the reaction was continued for 24 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solid. The solid was then settled in 200 mL of methanol, the supernatant was decanted, and the white precipitate was collected and dried. 1.20 g of polydodecanediol adipate, a white solid, was obtained, with a yield of 77%.

[0076] Using polystyrene as a standard, the number-average molecular weight was 9398, the weight-average molecular weight was 15534, and the dispersibility index was 1.65, as determined by gel permeation chromatography (GPC).

[0077] Example 5

[0078] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (39.5 mg, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 4 mol%), 1,12-dodecanediol (1.01 g, 5.0 mmol), and a toluene solution of 1,3-butadiene (13% w / w, 2.10 g, 5.0 mmol) were added, followed by a flush with 40 atm of carbon monoxide. The autoclave was incubated at 120 °C for 6 h, then the temperature was increased to 150 °C after 0.5 h, and the reaction was continued for 18 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solid. The solid was then settled in 200 mL of methanol, the supernatant was decanted, and the white precipitate was collected and dried. 1.25 g of poly(dodecanediol adipate) solid was obtained, with a yield of 80%.

[0079] Using polystyrene as a standard, the number-average molecular weight was 7412, the weight-average molecular weight was 11909, and the dispersibility index was 1.61, as determined by gel permeation chromatography (GPC).

[0080] Example 6

[0081] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (47.5 mg, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 4 mol%), 1,12-dodecanediol (1.01 g, 5.0 mmol), and 2 mL of toluene were added. In another small steel bottle, 1,3-butadiene (270 mg, 5.0 mmol) was introduced, and then the 1,3-butadiene was forced into the 45 mL autoclave using carbon monoxide at 40 atm. The autoclave was incubated at 120 °C for 6 h, then the temperature was increased to 150 °C after 0.5 h, and the reaction was continued for 24 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solid. The solid was then settled in 200 mL of methanol, the supernatant was decanted, and the white precipitate was collected and dried. 1.25 g of poly(dodecanediol adipate) solid was obtained, with a yield of 80%.

[0082] Using polystyrene as a standard, the number-average molecular weight was 10497, the weight-average molecular weight was 17603, and the dispersibility index was 1.68, as determined by gel permeation chromatography (GPC).

[0083] Comparative Example 1

[0084] The synthesis method of the polyadipate in this comparative example is basically the same as that in Example 2, except that the reaction in the autoclave is only heated for one stage and the reaction is carried out at 120°C for 30 hours.

[0085] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (39.5 mg, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 4 mol%), 1,12-dodecanediol (1.01 g, 5.0 mmol), and a toluene solution of 1,3-butadiene (13% w / w, 2.10 g, 5.0 mmol) were added, followed by a flush with 40 atm of carbon monoxide. The autoclave was incubated at 120 °C for 30 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solid. The solid was then settled in 200 mL of methanol, the supernatant was decanted, and the white precipitate was collected and dried. 0.99 g of poly(dodecanediol adipate) as a white solid was obtained, with a yield of 63%. Low molecular weight can also lead to incomplete sedimentation during methanol precipitation, resulting in a low yield.

[0086] Using polystyrene as a standard, the number-average molecular weight was 2854, the weight-average molecular weight was 6497, and the dispersibility index was 2.28, as determined by gel permeation chromatography (GPC).

[0087] Comparative Example 2

[0088] The synthesis method of the polyadipate in this comparative example is basically the same as that in Example 2, except that the reaction in the autoclave is only heated for one stage, and the reaction is carried out at 150°C for 30 hours.

[0089] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((di-tert-butylphosphino)methyl)benzene (39.5 mg, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 4 mol%), 1,12-dodecanediol (1.01 g, 5.0 mmol), and a toluene solution of 1,3-butadiene (13% w / w, 2.10 g, 5.0 mmol) were added, followed by a flush with 40 atm of carbon monoxide. The autoclave was incubated at 150 °C for 30 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solids. The solids were then settled in 200 mL of methanol, the supernatant was decanted, and the white precipitate was collected and dried. 1 ¹H NMR analysis showed that the precipitate contained no ester groups, indicating it was recovered 1,12-dodecanediol or an ether derived from its dehydration.

[0090] Comparative Example 3

[0091] The synthesis method of the polyadipate in this comparative example is basically the same as that in Example 2, except that the ligand used in the reaction is replaced with 1,2-bis((diphenylphosphino)methyl)benzene.

[0092] In a 45 mL autoclave, Pd(TFA)₂ (16.6 mg, 1 mol%), 1,2-bis((diphenylphosphino)methyl)benzene (47.5 mg, 2 mol%), dodecylbenzenesulfonic acid (65.3 mg, 4 mol%), 1,12-dodecanediol (1.01 g, 5.0 mmol), and a toluene solution of 1,3-butadiene (13% w / w, 2.10 g, 5.0 mmol) were added, followed by a flush with 40 atm of carbon monoxide. The autoclave was incubated at 120 °C for 6 h, then the temperature was increased to 150 °C after 0.5 h, and the reaction was continued for 24 h. After cooling and depressurization, 5 mL of dichloromethane was added to dissolve the solids. The solids were then settled in 200 mL of methanol, the supernatant was discarded, and the white precipitate was collected and dried. 1 ¹H NMR analysis showed that the precipitate contained no ester groups, indicating that it was the recovered 1,12-dodecanediol.

[0093] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing polyadipate from butadiene, characterized in that, Includes the following steps: S1. Mix palladium catalyst, phosphine ligand, acid additive, diol substrate, 1,3-butadiene, and organic solvent, introduce carbon monoxide, heat to react, and obtain reaction solution after the reaction is completed. S2. Dilute the reaction solution with a diluent and then drop it into a highly polar solvent to settle. Dry the resulting precipitate to obtain polyadipate. In step S1, the phosphine ligand is 1,2-bis((di-tert-butylphosphino)methyl)benzene; In step S1, the acid additive is selected from one or more of benzenesulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid; In step S1, the diol substrate includes one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol. In step S1, the heating reaction is divided into two stages. The first stage of heating is at a temperature of 110-130℃ and is held for 4-8 hours. The second stage of heating is at a temperature of 140-160℃ and is held for 22-26 hours. In step S2, the highly polar solvent is one or more of methanol and ethanol.

2. The method according to claim 1, characterized in that, In step S1, the palladium catalyst includes one or more of Pd(TFA)2, Pd2(dba)3, Pd(dba)2, Pd2(dba)3·CHCl3, PdCl2, PdCl2(CH3CN)2, PdBr2, PdI2, and Pd(OAc)2; And / or, the organic solvent includes one or more of toluene, xylene, trimethylbenzene, ethylbenzene, fluorobenzene, chlorobenzene, 1,4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, 1,2-dichloroethane, acetonitrile, N,N-dimethylformamide, and N,N-dimethylacetamide.

3. The method according to claim 1, characterized in that, In step S1, the molar amounts of each raw material are as follows: The ratio of 1,3-butadiene to diol substrate is 0.5 to 1.5:1; And / or, the ratio of 1,3-butadiene to palladium catalyst is 100,000 to 10:1; And / or, the ratio of phosphine ligand to palladium catalyst is 10 ~ 1:1; And / or, the ratio of acid additive to palladium catalyst is 100 ~ 1:

1.

4. The method according to claim 1, characterized in that, In step S1, adding 1,3-butadiene means adding a solution of 1,3-butadiene or introducing 1,3-butadiene gas.

5. The method according to claim 1, characterized in that, In step S1, the pressure of carbon monoxide is 1-100 bar.

6. The method according to claim 1, characterized in that, In step S2, the diluent is one or more of dichloromethane and tetrahydrofuran.

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