Method for synthesizing adipate by butadiene hydroesterification

Abstract

The present invention relates to a method for synthesizing adipate by butadiene hydroesterification. The method comprises the steps: a) dissolving a palladium catalyst, a phosphine ligand, an acid and butadiene in an alcohol and an optional solvent in a reaction kettle, the phosphine ligand being a phosphine ligand of formula I, formula II, formula V, formula VI and formula VIII; b) introducing carbon monoxide into the kettle, and reacting same; and c) ending the reaction and separating same to obtain a product. The method has the characteristics of high catalytic efficiency, high product yield, high selectivity, simple operation, etc.

Description

A method for synthesizing adipate by hydrogen esterification of butadiene Technical Field

[0001] This invention relates to the field of chemical production, and specifically, it provides a method for synthesizing adipate by hydrogen esterification of butadiene. Background Technology

[0002] Adipate esters are important C-6 platform compounds and are common polymer monomers for the synthesis of nylon 66, biodegradable polyesters, and polyurethanes. my country's production capacity reached 3 million tons in 2022, with a value of approximately 30 billion RMB. Currently, they are mainly produced through the nitric acid oxidation of cyclohexane or cyclohexene, a process with long routes, demanding production conditions, and high costs. In particular, it generates a large amount of the greenhouse gas nitrous oxide, necessitating a revolutionary new method for the synthesis of adipate esters. The one-step synthesis of adipate esters via butadiene hydrogen esterification is a simple and efficient route and represents one of the technological development trends in adipate ester production. However, existing technologies suffer from a series of problems, such as low selectivity and low conversion rates, which hinder the application of this process.

[0003] The hydrogen esterification of butadiene was first discovered by Brewis and Hughes et al. (Chem. Commun. 1965, 8, 157). Catalyzed by bis(butylphosphine) palladium iodide, butadiene reacts with carbon monoxide and methanol to produce methyl 3-pentenoate, with a yield reaching up to 68%. However, this reaction is subject to harsh conditions (>150℃, 100-1000 atm), resulting in low conversion and selectivity, and only producing a single hydrogen esterified product. BASF has achieved a two-step synthesis of adipate esters using a two-step hydrogen esterification process for butadiene. A novel method (US3161672, US3876695, US4259501) using a cobalt-based metal catalyst was proposed, but the reaction conditions were also harsh (>150℃, 100-300 atm), and the selectivity was only 60-80%. Subsequently, companies such as DuPont (US4777284) and Shell (US4861912, WO00056695) investigated the hydrogen esterification of butadiene to prepare adipate, but neither the conversion rate nor the selectivity was improved. Later, US4575562 disclosed a method using trialkyl or triarylphosphine as ligands and palladium-catalyzed hydrogen esterification of butadiene to synthesize adipate, but the conversion rate was only 50% and the selectivity only 70%.

[0004] In 2019, Beller et al. achieved a breakthrough in the direct hydrogen esterification of butadiene using their newly developed bisphosphine ligand, HeMaRaphos, generating dimethyl adipate with 95% conversion and 97% selectivity at 120 °C and 40 atm (Science 2019, 366, 1514–1517). In 2021, building on their previous work, the same group achieved palladium-catalyzed hydrogen esterification of butadiene to synthesize diadipate using the simpler bidentate phosphine ligand dtbpx (Angew. Chem. Int. Ed. 2021, 60, 9527). However, the highest turnover number (TON) of the above reactions was only 60,000, and the conversion frequency (TOF) was only about 1000 / hour, indicating that the catalytic efficiency still needs improvement. CN116925140 discloses the preparation of a heterogeneous catalyst based on bidentate phosphine ligand dtbpx and its application in the hydrogen esterification of butadiene to prepare adipate, but the conversion number of this reaction is 50,000, which has not been improved.

[0005] In summary, the existing palladium-catalyzed butadiene hydrogen esterification reaction has mild conditions, but its low catalytic activity results in low conversion number and conversion frequency, which affects the industrial application of this process. Summary of the Invention

[0006] The purpose of this invention is to provide a preparation process for adipate esters (including methyl ester, ethyl ester, butyl ester, or octyl ester, etc.).

[0007] In a first aspect of the present invention, a method for preparing adipate ester is provided, the method comprising the steps of:

[0008] a) In a reaction vessel, the palladium catalyst, phosphine ligand, acid and butadiene are dissolved in alcohol and optional solvent;

[0009] b) Introduce carbon monoxide into the reactor to carry out the reaction;

[0010] c) End the reaction and separate the product;

[0011] Wherein, the phosphine ligand of Formula I has a structure selected from the group below;

[0012] in,

[0013] R 1 Selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-12 cycloalkyl, substituted or unsubstituted C 6-30 Aryl;

[0014] R 2 Selected from the following group: substituted or unsubstituted 5-20 member heteroaryl groups;

[0015] R 3 C is hydrogen, substituted or unsubstituted 1-10 Alkyl, substituted or unsubstituted C 1-10 Alkoxy, substituted or unsubstituted C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 Alkyl), nitro, substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-30 membered heteroaryl; or two R atoms located on adjacent carbon atoms 3 The carbon atoms bonded to it together form a group selected from the following group: C 6- 10 Aryl, 5-12 heteroaryl;

[0016] In the ligands described, A is either substituted or unsubstituted C. 1-4 Alkylene Or the aforementioned A and Together in, This is the connection point connected to P;

[0017] Among them, R 4 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 quinone heteroaryl; or with R 3 One or more ring atoms on the pyridine ring together form a 5-7 membered carbon ring or heterocycle;

[0018] Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 heteroaryl.

[0019] In another preferred embodiment, in the ligand of formula I, A is CH2 or Or the aforementioned A and Together in, This is the connection point connected to P;

[0020] Among them, R 4 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl).

[0021] In another preferred embodiment, among the ligands of formula I,

[0022] R 1 Selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl groups;

[0023] R 2 Selected from the following group: substituted or unsubstituted 5-10 member heteroaryl groups;

[0024] R 3 For hydrogen, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, trialkylsilyl group (wherein the alkyl group is C10) 1-4 Alkyl), nitro, -CH(Ph)2, C 6-30 Aryl, 5-10 heteroaryl.

[0025] In another preferred embodiment, among the ligands of formula I,

[0026] R 1 Selected from the group consisting of: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, or phenyl;

[0027] R 2 Selected from the group consisting of: pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroleyl, imidazolyl, pyrazolyl, thiophenyl, furanyl, thiazolyl, triazolyl, quinolinyl, isoquinolinyl; and the R... 2 It may optionally be substituted by one or more substituents selected from the following group: C 1-4 alkyl;

[0028] R 3 Selected from the following group: methyl, n-propyl, isopropyl, tert-butyl, methoxy, cyano, COOH, -CH(Ph)2, benzenesulfonyl, trimethylsilyl, isoquinolinyl.

[0029] In another preferred embodiment, the ligands of formula I are selected from the group consisting of:

[0030] In another preferred embodiment, the reactor is a high-pressure reactor.

[0031] In another preferred embodiment, the amount of the phosphine ligand of Formula I is 0.00001 to 10% molar equivalent of the butadiene, more preferably 0.001 to 1% molar equivalent.

[0032] In another preferred embodiment, the reaction temperature is 0–200°C, preferably 60–130°C.

[0033] In another preferred embodiment, the reaction is carried out under the protection of an inert gas; preferably, the inert gas is nitrogen and / or argon.

[0034] In another preferred embodiment, the reaction is carried out at 1-10 MPa; more preferably, the reaction is carried out at 2-8 MPa.

[0035] In another preferred embodiment, the reaction time is 0.5 to 72 hours, preferably 0.5 to 24 hours.

[0036] In another preferred embodiment, the alcohol is C 1-12 Alkyl alcohols; preferably, the alcohols are selected from the group consisting of methanol, ethanol, propanol, butanol, octanol, or combinations thereof.

[0037] In another preferred embodiment, the amount of alcohol used in the reaction is 1-100 molar equivalents of the butadiene, preferably 1-10 molar equivalents.

[0038] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, palladium tetrafluoroborate tetraacetonitrile, palladium hexafluoroacetylacetonate, bis(acetylacetonate)palladium, palladium tetraacetonitrile trifluoromethanesulfonate, palladium neopentanoate, bis(dibenzylacetonate)palladium, tri(dibenzylacetonate)palladium, palladium chloride, (1,5-cyclooctadiene)palladium dichloride, palladium diacetonitrile dichloride, palladium dibenzonitrile dichloride, or combinations thereof.

[0039] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, tris(dibenzylacetone)palladium, palladium chloride, (1,5-cyclooctadiene)palladium dichloride, palladium diacetonitrile, or combinations thereof.

[0040] In another preferred embodiment, the amount of palladium catalyst used is 0.00001 to 10% molar equivalent of butadiene, more preferably 0.0001 to 1% molar equivalent.

[0041] In the reaction described, when the phosphine ligand of Formula I is a nitrogen phosphine ligand (i.e., the compound of Formula I), the molar ratio of the palladium catalyst to the nitrogen phosphine ligand is 1:1 to 1:30, more preferably 1:1 to 1:10.

[0042] In another preferred embodiment, the acid is selected from the group consisting of: perchloric acid, sulfuric acid, phosphoric acid, sulfonic acid, alkylphosphonic acid, alkylsulfonic acid, alkylcarboxylic acid, perfluoroalkylsulfonic acid, perfluoroalkylcarboxylic acid, or arylsulfonic acid.

[0043] In another preferred embodiment, the alkyl group is C10. 1-12 alkyl.

[0044] In another preferred embodiment, the aryl group is C 6-10 Aryl.

[0045] In another preferred embodiment, the acid is selected from the group consisting of: methanesulfonic acid, trifluoromethanesulfonic acid, tert-butanesulfonic acid, p-toluenesulfonic acid (PTSA), 2-hydroxypropane-2-sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, dodecyl sulfonic acid, sulfuric acid, sulfonic acid, formic acid, and trifluoroacetic acid.

[0046] In another preferred embodiment, the amount of acid used is 0.00004 to 40% molar equivalent of the butadiene, preferably 0.0004 to 4% molar equivalent.

[0047] In another preferred embodiment, the solvent is selected from the group consisting of alkane solvents, substituted aromatic solvents, ether solvents, ketone solvents, nitrile solvents, ester solvents, or combinations thereof.

[0048] In another preferred embodiment, the alkane solvent is selected from the group consisting of n-hexane, cyclohexane, or combinations thereof.

[0049] In another preferred embodiment, the substituted aromatic solvent is selected from the group consisting of chlorobenzene, toluene, xylene, and trifluorotoluene.

[0050] In another preferred embodiment, the ether solvent is selected from the group consisting of tetrahydrofuran, diethyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, anisole, ethylene glycol dimethyl ether, 1,4-dioxane, or combinations thereof.

[0051] In another preferred embodiment, the ketone solvent is selected from the group consisting of acetone.

[0052] In another preferred embodiment, the nitrile solvent is selected from the group consisting of acetonitrile, propionitrile, benzonitrile, or combinations thereof.

[0053] In another preferred embodiment, the ester solvent is selected from the group consisting of ethyl acetate.

[0054] In another preferred embodiment, the alcohol is methanol, and the reaction is carried out under the following conditions:

[0055] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in methanol or a mixture of solvents with optional solvents;

[0056] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0057] c) End the reaction and separate the product.

[0058] In another preferred embodiment, the alcohol is ethanol, and the reaction is carried out under the following conditions:

[0059] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in ethanol or a mixture of solvents with optional solvents;

[0060] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0061] c) End the reaction and separate the product.

[0062] In another preferred embodiment, the alcohol is butanol, and the reaction is carried out under the following conditions:

[0063] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in butanol or a mixture thereof with an optional solvent.

[0064] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0065] c) End the reaction and separate the product.

[0066] In another preferred embodiment, the alcohol is octanol, and the reaction is carried out under the following conditions:

[0067] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in octanol or a mixture thereof with an optional solvent.

[0068] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0069] c) End the reaction and separate the product.

[0070] In a first aspect of the present invention, a method for preparing adipate esters (including methyl ester, ethyl ester, butyl ester, or octyl ester, etc.) is provided, the method comprising the steps of:

[0071] a) In a reaction vessel, the palladium catalyst, phosphine ligand, acid and butadiene are dissolved in alcohol and optional solvent;

[0072] b) Introduce carbon monoxide into the reactor to carry out the reaction;

[0073] c) End the reaction and separate the product;

[0074] Wherein, the phosphine ligand of Formula II has a structure selected from the group shown below;

[0075] in,

[0076] R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-12 Cycloalkyl, substituted or unsubstituted 3-12 membered heterocyclic alkyl, substituted or unsubstituted C 6-30 Aryl;

[0077] R 2 and R 3 Each is an independent substituted or unsubstituted 5-20 heteroaryl group;

[0078] A is selected from the following group:

[0079] Among them, R 5 R 6 R 7 R 8 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 R 6 R 7 R 8 The ring atoms attached to it together form a 5-7 membered carbon ring or heterocycle; Y is one of O, NH or S;

[0080] Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 heteroaryl.

[0081] In another preferred embodiment, among the ligands of formula II,

[0082] R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C1-4 Alkyl, substituted or unsubstituted C 3- 10 cycloalkyl, phenyl;

[0083] R 2 and R 3 Each is independently selected from the following group: substituted or unsubstituted 5-10 heteroaryl groups;

[0084] Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 heteroaryl.

[0085] In another preferred embodiment, among the ligands of formula II,

[0086] R 1 and R 4 Each of the following is independently selected: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl or phenyl;

[0087] R 2 and R 3 Each of the following groups is selected independently: pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroleyl, imidazolyl, pyrazolyl, thiopheneyl, furanyl, thiazolyl, triazolyl, quinolinyl, benzoxazolyl.

[0088] In another preferred embodiment, among the ligands of formula II,

[0089] R 5 R 6 R 7 R 8 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-10 aryl, 5-10 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 R 6 R 7 R 8 The ring atoms attached to it together form 5-7 membered carbon rings or heterocycles.

[0090] In another preferred embodiment, the ligands of formula II are selected from the group consisting of:

[0091] In another preferred embodiment, the reactor is a high-pressure reactor.

[0092] In another preferred embodiment, the amount of the phosphine ligand of Formula II is 0.00001 to 10% molar equivalent of the butadiene, more preferably 0.0001 to 1% molar equivalent.

[0093] In another preferred embodiment, the reaction temperature is 0–200°C, preferably 60–130°C.

[0094] In another preferred embodiment, the reaction is carried out under the protection of an inert gas; preferably, the inert gas is nitrogen and / or argon.

[0095] In another preferred embodiment, the reaction is carried out at 1-10 MPa; more preferably, the reaction is carried out at 2-8 MPa.

[0096] In another preferred embodiment, the reaction time is 0.5 to 72 hours, preferably 0.5 to 24 hours.

[0097] In another preferred embodiment, the alcohol is C 1-12 Alkyl alcohols; preferably, the alcohols are selected from the group consisting of methanol, ethanol, propanol, butanol, octanol, or combinations thereof.

[0098] In another preferred embodiment, the amount of alcohol used in the reaction is 1-100 molar equivalents of the butadiene, preferably 1-10 molar equivalents.

[0099] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, palladium tetrafluoroborate tetraacetonitrile, palladium hexafluoroacetylacetonate, bis(acetylacetonate)palladium, palladium tetraacetonitrile trifluoromethanesulfonate, palladium neopentanoate, bis(dibenzylacetone)palladium, tri(dibenzylacetone)dipalladium, palladium chloride, (1,5-cyclooctadiene)palladium dichloride, palladium diacetonitrile dichloride, palladium dibenzonitrile dichloride, or combinations thereof.

[0100] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, tris(dibenzylideneacetone)palladium, (1,5-cyclooctadiene)palladium dichloride, palladium chloride, or combinations thereof.

[0101] In another preferred embodiment, the amount of palladium catalyst used is 0.00001 to 10% molar equivalent of the butadiene. More preferably, it is 0.0001 to 1% molar equivalent.

[0102] In the reaction described, when the phosphine ligand of Formula II is a bisphosphine ligand (i.e., the compound of Formula II), the molar ratio of the palladium catalyst to the bisphosphine ligand is 1:0.5 to 1:30, more preferably 1:1 to 1:5.

[0103] In another preferred embodiment, the acid is selected from the group consisting of perchloric acid, sulfuric acid, phosphoric acid, sulfonic acid, alkylphosphonic acid, alkylsulfonic acid, alkylcarboxylic acid, or arylsulfonic acid.

[0104] In another preferred embodiment, the alkyl group is C10. 1-12 alkyl.

[0105] In another preferred embodiment, the aryl group is C 6-10 Aryl.

[0106] In another preferred embodiment, the acid is selected from the group consisting of: methanesulfonic acid, trifluoromethanesulfonic acid, tert-butanesulfonic acid, p-toluenesulfonic acid (PTSA), 2-hydroxypropane-2-sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, dodecyl sulfonic acid, sulfuric acid, sulfonic acid, formic acid, and trifluoroacetic acid.

[0107] In another preferred embodiment, the amount of acid used is 0.00004 to 40% molar equivalent of the butadiene, preferably 0.0004 to 4% molar equivalent.

[0108] In another preferred embodiment, the solvent is selected from the group consisting of alkane solvents, substituted aromatic solvents, ether solvents, ketone solvents, nitrile solvents, ester solvents, or combinations thereof.

[0109] In another preferred embodiment, the alkane solvent is selected from the group consisting of n-hexane, cyclohexane, or combinations thereof.

[0110] In another preferred embodiment, the substituted aromatic solvent is selected from the group consisting of chlorobenzene, toluene, and trifluorotoluene.

[0111] In another preferred embodiment, the ether solvent is selected from the group consisting of tetrahydrofuran, diethyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, anisole, ethylene glycol dimethyl ether, 1,4-dioxane, or combinations thereof.

[0112] In another preferred embodiment, the ketone solvent is selected from the group consisting of acetone.

[0113] In another preferred embodiment, the nitrile solvent is selected from the group consisting of acetonitrile, propionitrile, benzonitrile, or combinations thereof.

[0114] In another preferred embodiment, the ester solvent is selected from the group consisting of ethyl acetate.

[0115] In another preferred embodiment, the alcohol is methanol, and the reaction is carried out under the following conditions:

[0116] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in methanol or a mixture of solvents with optional solvents;

[0117] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0118] c) End the reaction and separate the product.

[0119] In another preferred embodiment, the alcohol is ethanol, and the reaction is carried out under the following conditions:

[0120] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in ethanol or a mixture of solvents with optional solvents;

[0121] b) Reacting carbon monoxide in the reactor, wherein the reaction is carried out at room temperature to 130°C;

[0122] c) End the reaction and separate the product.

[0123] In another preferred embodiment, the alcohol is propanol, and the reaction is carried out under the following conditions:

[0124] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in propanol or a mixture of propanol and optional solvent;

[0125] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0126] c) End the reaction and separate the product.

[0127] In another preferred embodiment, the alcohol is butanol, and the reaction is carried out under the following conditions:

[0128] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in butanol or a mixture thereof with an optional solvent.

[0129] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0130] c) End the reaction and separate the product.

[0131] In another preferred embodiment, the alcohol is octanol, and the reaction is carried out under the following conditions:

[0132] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in octanol or a mixture thereof with an optional solvent.

[0133] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0134] c) End the reaction and separate the product.

[0135] In a third aspect of the present invention, a method for preparing adipate esters (including methyl ester, ethyl ester, butyl ester, or octyl ester, etc.) is provided, the method comprising the steps of:

[0136] a) In a reaction vessel, the palladium catalyst, phosphine ligand, acid and butadiene are dissolved in alcohol and optional solvent;

[0137] b) Introduce carbon monoxide into the reactor to carry out the reaction;

[0138] c) End the reaction and separate the product;

[0139] Wherein, the phosphine ligand represented by formula V has a structure selected from the group below;

[0140] in,

[0141] R 1 Selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30 Aryl; and R 2 Selected from the group consisting of substituted or unsubstituted 5-20 membered heteroaryl groups; or

[0142] R 1 Selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30 Aryl; and R 2 Selected from the following group: substituted or unsubstituted C 6-30 Aryl;

[0143] R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 Each is independently selected from the following group: hydrogen, hydroxyl, halogen, substituted or unsubstituted C. 1-12 Alkyl, substituted or unsubstituted C 3-12 cycloalkyl, substituted or unsubstituted C 3-10 Heterocyclic alkyl, substituted or unsubstituted C 2-10 alkenyl, substituted or unsubstituted C 5-30 aryl, substituted or unsubstituted C 4-30 heteroaryl, C 1-10 Alkoxy, C 1-10 Alkylamino, C1-10 Alkyl thio; R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 Any two of them, together with the carbon atoms they are attached to, form a 4-8 membered carbon ring or a heterocycle;

[0144] A is -L 1 -A 1 -L 2 -, where L 1 A 1 and L 2 Each is independently selected from the following groups: none, chemical bond, O, NH, S, substituted or unsubstituted C. 1-12 Alkyl, substituted or unsubstituted C 3-8 cycloalkyl, substituted or unsubstituted C 3-8 Heterocyclic alkyl, substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-20 membered heteroaryl, substituted or unsubstituted biphenyl, substituted or unsubstituted Replaced or not replaced And L 1 A 1 and L 2 Not simultaneously without chemical bonds; wherein, when the aryl (including phenyl) or heteroaryl is replaced by two or more substituents, any two substituents can together with the ring atom attached to them form a 4-8 membered carbon ring or heterocycle; M is Fe, Co or Ru;

[0145] B is selected from the following group: substituted or unsubstituted methylene, ethylene, C=CHR, C=NR, hydroxymethyl, carbonyl, thiocarbonyl. -C(O)-C(O)-; where R is a substituted or unsubstituted C 1-10 Alkyl, or substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-20 membered heteroaryl;

[0146] R 11 R 12 Each is independently selected from the following group: H, OH, substituted or unsubstituted C. 1-10 alkyl, or It constitutes a 5-8 membered heterocycle, and the heterocycle may be substituted or unsubstituted;

[0147] X is O, S; Z is O, S or NH;

[0148] Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 heteroaryl, benzyl, -CH(Ph)2.

[0149] In another preferred embodiment, among the ligands of formula V,

[0150] R 1 C is selected from the group consisting of substituted or unsubstituted C. 1-12 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-20 Aryl;

[0151] R 2 Selected from the following group: substituted or unsubstituted 5-12 heteroaryl groups; or R 1 Selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl; and R 2 C is selected from the group consisting of substituted or unsubstituted C. 6-20 Aryl.

[0152] In another preferred embodiment, R 1 Selected from the group consisting of substituted or unsubstituted molecules: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, or phenyl; R 2 Selected from the following group of substituted or unsubstituted compounds: pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroloyl, imidazolyl, pyrazolyl, thiophenyl, furanyl, thiazolyl, oxazolyl; or

[0153] R 1 Selected from the group consisting of substituted or unsubstituted: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl; and R 2 It is selected from the group consisting of substituted or unsubstituted phenyl groups.

[0154] In another preferred embodiment, among the ligands of formula V,

[0155] R 3 R 4 R 5 R 6 R 7 R 8 R 9R 10 Each is independently selected from the following group: hydrogen, substituted or unsubstituted C. 1-12 Alkyl, substituted or unsubstituted C 3-12 cycloalkyl, substituted or unsubstituted C 3-10 Heterocyclic alkyl, substituted or unsubstituted C 2-10 alkenyl, C 1-10 Alkoxy, C 1-10 Alkylamino, C 1-10 alkyl thio; or R 3 R 10 The carbon atoms attached to it together form 4-8 membered carbon rings or heterocycles;

[0156] B is selected from the following group: substituted or unsubstituted methylene, ethylene, =NR, hydroxymethyl, carbonyl. -C(O)-C(O)-; where R is a substituted or unsubstituted C 1-10 Alkyl, or phenyl;

[0157] R 11 R 12 Each is independently selected from the following group: H, OH, substituted or unsubstituted C. 1-6 alkyl, or It constitutes a 5-8 membered heterocycle, and the heterocycle may be unsubstituted or C-substituted. 1-6 Alkyl-substituted;

[0158] X represents O and S.

[0159] In another preferred embodiment, in the ligand of formula V, L 1 Selected from the following group: C with no chemical bond, chemical bond, substituted or unsubstituted. 1-6 Alkyl groups;

[0160] A 1 and L 2 Each is independently selected from the following groups: chemical bonds, substituted or unsubstituted C. 1-6 Alkyl, substituted or unsubstituted C3-8 cycloalkyl, substituted or unsubstituted C 3-8 Heterocyclic alkyl, substituted or unsubstituted C 6- 10 Aryl, substituted or unsubstituted 5-10-membered heteroaryl, substituted or unsubstituted biphenyl, substituted or unsubstituted ferrocene; substituted or unsubstituted Z represents O and S;

[0161] Or A 1 It is O, and L 1 and L 2 Each is independently selected from the following group: substituted or unsubstituted C 6-10Aryl, substituted or unsubstituted 5-10 heteroaryl groups.

[0162] In another preferred embodiment, among the ligands of formula V,

[0163] A is a structure selected from the following group:

[0164] Among them, R 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 R 24 R 25 These are one or more substituents selected from the following group located on the corresponding ring: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 The ring atoms attached to it together form 5-7 membered carbon rings or heterocycles;

[0165] x is selected from 0, 1, 2, 3, 4 or 5;

[0166] m and n are 0, 1, 2, and 3 respectively;

[0167] M is Fe, Co, or Ru; Z is O, S, or NH;

[0168] V, W, and Y are either N or CH, and may be the same or different; and the hydrogen atom on CH can be R. 18 replace;

[0169] Selected from the following group:

[0170] Among them, Ar 1Selected from substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-20 heteroaryl groups.

[0171] In another preferred embodiment, the ligands of formula V are selected from the group consisting of:

[0172] In another preferred embodiment, the reactor is a high-pressure reactor.

[0173] In another preferred embodiment, the amount of the phosphine ligand of formula V is 0.00001 to 10% molar equivalent of the butadiene, more preferably 0.0001 to 1% molar equivalent.

[0174] In another preferred embodiment, the reaction temperature is 0–200°C, preferably 40–130°C.

[0175] In another preferred embodiment, the reaction is carried out under the protection of an inert gas; preferably, the inert gas is nitrogen and / or argon.

[0176] In another preferred embodiment, the reaction is carried out at 1-10 MPa; more preferably, the reaction is carried out at 2-8 MPa.

[0177] In another preferred embodiment, the reaction time is 0.5 to 72 hours, preferably 0.5 to 24 hours.

[0178] In another preferred embodiment, the alcohol is C 1-12 Alkyl alcohols; preferably, the alcohols are selected from the group consisting of methanol, ethanol, propanol, butanol, octanol, or combinations thereof.

[0179] In another preferred embodiment, the amount of alcohol used in the reaction is 1-100 molar equivalents of the butadiene, preferably 1-10 molar equivalents.

[0180] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, palladium tetrafluoroborate tetraacetonitrile, palladium hexafluoroacetylacetonate, bis(acetylacetonate)palladium, palladium tetraacetonitrile trifluoromethanesulfonate, palladium neopentanoate, bis(dibenzylacetone)palladium, tri(dibenzylacetone)dipalladium, palladium chloride, (1,5-cyclooctadiene)palladium dichloride, palladium diacetonitrile dichloride, palladium dibenzonitrile dichloride, or combinations thereof.

[0181] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, tris(dibenzylideneacetone)palladium, (1,5-cyclooctadiene)palladium dichloride, palladium chloride, or combinations thereof.

[0182] In another preferred embodiment, the amount of palladium catalyst used is 0.00001 to 10% molar equivalent of the ethylene. More preferably, it is 0.0001 to 1% molar equivalent.

[0183] In the reaction described, when the phosphine ligand of formula V is a bisphosphine ligand (i.e., compound of formula V), the molar ratio of the palladium catalyst to the bisphosphine ligand is 1:1 to 1:30, more preferably 1:1 to 1:5.

[0184] In another preferred embodiment, the acid is selected from the group consisting of: perchloric acid, sulfuric acid, phosphoric acid, sulfonic acid, alkylphosphonic acid, alkylsulfonic acid, alkylcarboxylic acid, perfluoroalkylsulfonic acid, perfluoroalkylcarboxylic acid, or arylsulfonic acid.

[0185] In another preferred embodiment, the alkyl group is C10. 1-12 alkyl.

[0186] In another preferred embodiment, the aryl group is C 6-10 Aryl.

[0187] In another preferred embodiment, the acid is selected from the group consisting of: methanesulfonic acid, trifluoromethanesulfonic acid, tert-butanesulfonic acid, p-toluenesulfonic acid (PTSA), 2-hydroxypropane-2-sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, dodecyl sulfonic acid, sulfuric acid, sulfonic acid, formic acid, and trifluoroacetic acid.

[0188] In another preferred embodiment, the amount of acid used is 0.00004 to 40% molar equivalent of the butadiene, preferably 0.0004 to 4% molar equivalent.

[0189] In another preferred embodiment, the inert solvent is selected from the group consisting of alkane solvents, substituted aromatic solvents, ether solvents, ketone solvents, nitrile solvents, ester solvents, or combinations thereof.

[0190] In another preferred embodiment, the alkane solvent is selected from the group consisting of n-hexane, cyclohexane, or combinations thereof.

[0191] In another preferred embodiment, the substituted aromatic solvent is selected from the group consisting of chlorobenzene, toluene, xylene, and trifluorotoluene.

[0192] In another preferred embodiment, the ether solvent is selected from the group consisting of tetrahydrofuran, diethyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, anisole, ethylene glycol dimethyl ether, 1,4-dioxane, or combinations thereof.

[0193] In another preferred embodiment, the ketone solvent is selected from the group consisting of acetone.

[0194] In another preferred embodiment, the nitrile solvent is selected from the group consisting of acetonitrile, propionitrile, benzonitrile, or combinations thereof.

[0195] In another preferred embodiment, the ester solvent is selected from the group consisting of ethyl acetate.

[0196] In another preferred embodiment, the alcohol is methanol, and the reaction is carried out under the following conditions:

[0197] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in methanol or a mixture of solvents with optional solvents;

[0198] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 120°C;

[0199] c) End the reaction and separate the product.

[0200] In another preferred embodiment, the alcohol is ethanol, and the reaction is carried out under the following conditions:

[0201] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in ethanol or a mixture of solvents with optional solvents;

[0202] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 120°C;

[0203] c) End the reaction and separate the product.

[0204] In another preferred embodiment, the alcohol is butanol, and the reaction is carried out under the following conditions:

[0205] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in butanol or a mixture thereof with an optional solvent.

[0206] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 120°C;

[0207] c) End the reaction and separate the product.

[0208] In another preferred embodiment, the alcohol is octanol, and the reaction is carried out under the following conditions:

[0209] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in octanol or a mixture thereof with an optional solvent.

[0210] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 120°C;

[0211] c) End the reaction and separate the product.

[0212] In a fourth aspect of the present invention, a method for preparing adipate esters (including methyl ester, ethyl ester, butyl ester, or octyl ester, etc.) is provided, the method comprising the steps of:

[0213] a) In a reaction vessel, the palladium catalyst, phosphine ligand, acid and butadiene are dissolved in alcohol and optional solvent;

[0214] b) Introduce carbon monoxide into the reactor to carry out the reaction;

[0215] c) End the reaction and separate the product;

[0216] Wherein, the phosphine ligand of formula VI has a structure selected from the group consisting of:

[0217] in,

[0218] R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30 Aryl;

[0219] R 2 and R 3 Each is independently selected from the group consisting of substituted or unsubstituted 5-20 heteroaryl groups;

[0220] R 5 R 6 Each is an independent substituent located on the corresponding ring and selected from the following groups: H, C 1- 10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 R 6 The ring atoms connected to it together form a 5-7 membered carbon ring or heterocycle, wherein the heterocycle may have 1-3 heteroatoms selected from the group consisting of N, O or S;

[0221] Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 aryl, halogen, haloalkyl, benzyl.

[0222] In another preferred embodiment, in the ligand of formula VI,

[0223] R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-4 Alkyl, substituted or unsubstituted C 3- 6-cycloalkyl, substituted or unsubstituted C 6-14 Aryl;

[0224] R 2 and R 3 Each is independently selected from the following group: substituted or unsubstituted 5-20 heteroaryl groups;

[0225] Wherein, the R 1 R 2 R 3 and R 4 Each is independently unsubstituted or substituted by 1-2 substituents selected from the group consisting of: methyl, methoxy, cyano, COOH, benzenesulfonyl, trimethylsilyl, halogen, haloalkyl, benzyl.

[0226] In another preferred embodiment, in the ligand of formula VI,

[0227] R 1 and R 4 Each of the following is independently selected: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl or adamantyl;

[0228] R 2 and R 3 Each of the following groups is independently substituted or unsubstituted: pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroleyl, imidazolyl, pyrazolyl, thiopheneyl, furanyl, thiazolyl, triazolyl.

[0229] In another preferred embodiment, the ligands in formula VI are selected from the group consisting of:

[0230] In another preferred embodiment, the reactor is a high-pressure reactor.

[0231] In another preferred embodiment, the amount of the phosphine ligand of Formula VI is 0.00001 to 10% molar equivalent of the butadiene, more preferably 0.0001 to 1% molar equivalent.

[0232] In another preferred embodiment, the reaction temperature is 0–200°C, preferably 60–150°C.

[0233] In another preferred embodiment, the reaction is carried out under the protection of an inert gas; preferably, the inert gas is nitrogen and / or argon.

[0234] In another preferred embodiment, the reaction is carried out at 1-10 MPa; more preferably, the reaction is carried out at 2-8 MPa.

[0235] In another preferred embodiment, the reaction time is 0.2 to 72 hours, preferably 0.2 to 24 hours.

[0236] In another preferred embodiment, the alcohol is C 1-12 Alkyl alcohols; preferably, the alcohols are selected from the group consisting of methanol, ethanol, propanol, butanol, octanol, or combinations thereof.

[0237] In another preferred embodiment, the amount of alcohol used in the reaction is 1-100 molar equivalents of the butadiene, preferably 1-10 molar equivalents.

[0238] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, palladium tetrafluoroborate tetraacetonitrile, palladium hexafluoroacetylacetonate, bis(acetylacetonate)palladium, palladium tetraacetonitrile trifluoromethanesulfonate, palladium neopentanoate, bis(dibenzylacetonate)palladium, tri(dibenzylacetonate)palladium, palladium chloride, (1,5-cyclooctadiene)palladium dichloride, palladium diacetonitrile dichloride, palladium dibenzonitrile dichloride, or combinations thereof.

[0239] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, tris(dibenzylideneacetone)palladium, (1,5-cyclooctadiene)palladium dichloride, palladium chloride, or combinations thereof.

[0240] In another preferred embodiment, the amount of palladium catalyst used is 0.00001 to 10% molar equivalent of butadiene, more preferably 0.0001 to 1% molar equivalent.

[0241] In another preferred embodiment, when the phosphine ligand is a bisphosphine ligand (i.e., compound of formula I), the molar ratio of the palladium catalyst to the bisphosphine ligand is 1:1 to 1:30, more preferably 1:1 to 1:5.

[0242] In another preferred embodiment, the acid is selected from the group consisting of: perchloric acid, sulfuric acid, phosphoric acid, sulfonic acid, alkylphosphonic acid, alkylsulfonic acid, alkylcarboxylic acid, perfluoroalkylsulfonic acid, perfluoroalkylcarboxylic acid, or arylsulfonic acid.

[0243] In another preferred embodiment, the alkyl group is C10. 1-12 alkyl.

[0244] In another preferred embodiment, the aryl group is C 6-10 Aryl.

[0245] In another preferred embodiment, the acid is selected from the group consisting of: methanesulfonic acid, trifluoromethanesulfonic acid, tert-butanesulfonic acid, p-toluenesulfonic acid (PTSA), 2-hydroxypropane-2-sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, dodecyl sulfonic acid, sulfuric acid, sulfonic acid, formic acid, and trifluoroacetic acid.

[0246] In another preferred embodiment, the amount of acid used is 0.00004 to 40% molar equivalent of the butadiene, preferably 0.0004 to 4% molar equivalent.

[0247] In another preferred embodiment, the solvent is selected from the group consisting of alkane solvents, substituted aromatic solvents, ether solvents, ketone solvents, nitrile solvents, ester solvents, or combinations thereof.

[0248] In another preferred embodiment, the alkane solvent is selected from the group consisting of n-hexane, cyclohexane, or combinations thereof.

[0249] In another preferred embodiment, the substituted aromatic solvent is selected from the group consisting of chlorobenzene, toluene, xylene, and trifluorotoluene.

[0250] In another preferred embodiment, the ether solvent is selected from the group consisting of tetrahydrofuran, diethyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, anisole, ethylene glycol dimethyl ether, 1,4-dioxane, or combinations thereof.

[0251] In another preferred embodiment, the ketone solvent is selected from the group consisting of acetone.

[0252] In another preferred embodiment, the nitrile solvent is selected from the group consisting of acetonitrile, propionitrile, benzonitrile, or combinations thereof.

[0253] In another preferred embodiment, the ester solvent is selected from the group consisting of ethyl acetate, dimethyl adipate, ethyl adipate, butyl adipate, octyl adipate, or combinations thereof.

[0254] In another preferred embodiment, the alcohol is methanol, and the reaction is carried out under the following conditions:

[0255] a) Dissolve palladium trifluoroacetate, phosphine ligand, and acid in methanol and an optional solvent;

[0256] b) Butadiene is introduced into the reactor, followed by carbon monoxide to carry out the reaction, wherein the reaction is carried out at room temperature to 60-100°C;

[0257] c) End the reaction and separate the product.

[0258] In another preferred embodiment, the alcohol is ethanol, and the reaction is carried out under the following conditions:

[0259] a) Dissolve palladium trifluoroacetate, phosphine ligand, and acid in ethanol and optional solvents;

[0260] b) Butadiene is introduced into the reactor, followed by carbon monoxide to carry out the reaction, wherein the reaction is carried out at room temperature to 60-100°C;

[0261] c) End the reaction and separate the product.

[0262] In another preferred embodiment, the alcohol is butanol, and the reaction is carried out under the following conditions:

[0263] a) Dissolve palladium trifluoroacetate, phosphine ligand, and acid in butanol and an optional solvent.

[0264] b) Butadiene is introduced into the reactor, followed by carbon monoxide to carry out the reaction, wherein the reaction is carried out at room temperature to 60-100°C;

[0265] c) End the reaction and separate the product.

[0266] In another preferred embodiment, the alcohol is octanol, and the reaction is carried out under the following conditions:

[0267] a) Dissolve palladium trifluoroacetate, the phosphine ligand, and the acid in octanol and an optional solvent.

[0268] b) Butadiene is introduced into the reactor, followed by carbon monoxide to carry out the reaction, wherein the reaction is carried out at room temperature to 60-100°C;

[0269] c) End the reaction and separate the product.

[0270] In a fifth aspect of the present invention, a method for preparing adipate esters (including methyl ester, ethyl ester, butyl ester, or octyl ester, etc.) is provided, the method comprising the steps of:

[0271] a) In a reaction vessel, the palladium catalyst, phosphine ligand, acid and butadiene are dissolved in alcohol and optional solvent;

[0272] b) Introduce carbon monoxide into the reactor to carry out the reaction;

[0273] c) End the reaction and separate the product;

[0274] Wherein, the phosphine ligand of formula VIII has a structure selected from the group below;

[0275] in,

[0276] R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30Aryl;

[0277] R 2 and R 3 Each is independently selected from the group consisting of substituted or unsubstituted 5-20 heteroaryl groups;

[0278] A represents unsubstituted or unreplaced by one or more R's. 6 The substituted 5-10-membered heteroaryl group, wherein the heteroatom in the heteroaryl group is one or more of O, N, and S, and may be the same or different;

[0279] R 5 and R 6 Each is an independent substituent located on the corresponding ring and selected from the following groups: H, C 1- 10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 The ring atoms attached to it together form 5-7 membered carbon rings or heterocycles;

[0280] Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 quinone heteroaryl, halogen, haloalkyl.

[0281] In another preferred embodiment, when A is pyrrole, the compound satisfies any 1-3 of the following conditions (1)-(3):

[0282] (1)R 5 R 6 They are not both hydrogen;

[0283] (2)R 1 R 4 Not both tert-butyl;

[0284] (3)R 2 and R 3 It is not 2-pyridyl.

[0285] In another preferred embodiment, among the ligands of formula VIII,

[0286] R 1and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-4 Alkyl, substituted or unsubstituted C 3- 10 cycloalkyl, phenyl;

[0287] R 2 and R 3 Each is independently selected from the following group: substituted or unsubstituted 5-20 heteroaryl groups;

[0288] Wherein, the R 1 R 2 R 3 and R 4 Each is independently unsubstituted or substituted by 1-2 substituents selected from the group consisting of: methyl, methoxy, cyano, COOH, benzenesulfonyl, trimethylsilyl, halogen, and haloalkyl.

[0289] In another preferred embodiment, A is unsubstituted or substituted by one or more R. 6 The substituted 5-9-membered heteroaryl group, wherein the heteroatom in the heteroaryl group is one or more of O, N, and S, and may be the same or different.

[0290] In another preferred embodiment, among the ligands of formula VIII,

[0291] R 1 and R 4 Each of the following is independently selected: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl or phenyl;

[0292] R 2 and R 3 Each of the following groups is independently substituted or unsubstituted: pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroleyl, imidazolyl, pyrazolyl, thiopheneyl, furanyl, thiazolyl, triazolyl;

[0293] Wherein, the R 1 R 2 R 3 and R 4 Each is independently unsubstituted or substituted by 1-2 substituents selected from the group consisting of: methyl, methoxy, cyano, COOH, benzenesulfonyl, and trimethylsilyl.

[0294] In another preferred embodiment, the ligands of formula VIII are selected from the group consisting of:

[0295] In another preferred embodiment, the reactor is a high-pressure reactor.

[0296] In another preferred embodiment, the amount of the phosphine ligand of Formula VIII is 0.00001 to 10% molar equivalent of the butadiene, more preferably 0.0001 to 1% molar equivalent.

[0297] In another preferred embodiment, the reaction temperature is 0–200°C, preferably 40–130°C.

[0298] In another preferred embodiment, the reaction is carried out under the protection of an inert gas; preferably, the inert gas is nitrogen and / or argon.

[0299] In another preferred embodiment, the reaction is carried out at 1-10 MPa; more preferably, the reaction is carried out at 2-8 MPa.

[0300] In another preferred embodiment, the reaction time is 0.5 to 72 hours, preferably 0.5 to 24 hours.

[0301] In another preferred embodiment, the alcohol is C 1-12 Alkyl alcohols; preferably, the alcohols are selected from the group consisting of methanol, ethanol, propanol, butanol, octanol, or combinations thereof.

[0302] In another preferred embodiment, the amount of alcohol used in the reaction is 1-100 molar equivalents of the butadiene, preferably 1-10 molar equivalents.

[0303] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, palladium tetrafluoroborate tetraacetonitrile, palladium hexafluoroacetylacetonate, bis(acetylacetonate)palladium, palladium tetraacetonitrile trifluoromethanesulfonate, palladium neopentanoate, bis(dibenzylacetonate)palladium, tri(dibenzylacetonate)palladium, palladium chloride, (1,5-cyclooctadiene)palladium dichloride, palladium diacetonitrile dichloride, palladium dibenzonitrile dichloride, or combinations thereof.

[0304] In another preferred embodiment, the palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, tris(dibenzylideneacetone)palladium, (1,5-cyclooctadiene)palladium dichloride, palladium chloride, or combinations thereof.

[0305] In another preferred embodiment, the amount of palladium catalyst used is 0.00001 to 10% molar equivalent of butadiene, more preferably 0.001 to 1% molar equivalent.

[0306] In another preferred embodiment, in the reaction, when the phosphine ligand of formula VIII is a bisphosphine ligand (i.e., the compound of formula VIII), the molar ratio of the palladium catalyst to the bisphosphine ligand is 1:1 to 1:30, more preferably 1:1 to 1:5.

[0307] In another preferred embodiment, the acid is selected from the group consisting of: perchloric acid, sulfuric acid, phosphoric acid, sulfonic acid, alkylphosphonic acid, alkylsulfonic acid, alkylcarboxylic acid, perfluoroalkylsulfonic acid, perfluoroalkylcarboxylic acid, and arylsulfonic acid.

[0308] In another preferred embodiment, the alkyl group is C10. 1-12 alkyl.

[0309] In another preferred embodiment, the aryl group is C 6-10 Aryl.

[0310] In another preferred embodiment, the acid is selected from the group consisting of: methanesulfonic acid, trifluoromethanesulfonic acid, tert-butanesulfonic acid, p-toluenesulfonic acid (PTSA), 2-hydroxypropane-2-sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, dodecyl sulfonic acid, sulfuric acid, sulfonic acid, formic acid, and trifluoroacetic acid.

[0311] In another preferred embodiment, the amount of acid used is 0.00004 to 40% molar equivalent of the butadiene, preferably 0.004 to 4% molar equivalent.

[0312] In another preferred embodiment, the solvent is selected from the group consisting of alkane solvents, substituted aromatic solvents, ether solvents, ketone solvents, nitrile solvents, ester solvents, or combinations thereof.

[0313] In another preferred embodiment, the alkane solvent is selected from the group consisting of n-hexane, cyclohexane, or combinations thereof.

[0314] In another preferred embodiment, the substituted aromatic solvent is selected from the group consisting of chlorobenzene, toluene, xylene, and trifluorotoluene.

[0315] In another preferred embodiment, the ether solvent is selected from the group consisting of tetrahydrofuran, diethyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, anisole, ethylene glycol dimethyl ether, 1,4-dioxane, or combinations thereof.

[0316] In another preferred embodiment, the ketone solvent is selected from the group consisting of acetone.

[0317] In another preferred embodiment, the nitrile solvent is selected from the group consisting of acetonitrile, propionitrile, benzonitrile, or combinations thereof.

[0318] In another preferred embodiment, the ester solvent is selected from the group consisting of ethyl acetate.

[0319] In another preferred embodiment, the alcohol is methanol, and the reaction is carried out under the following conditions:

[0320] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in methanol or a mixture of solvents with optional solvents;

[0321] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0322] c) End the reaction and separate the product.

[0323] In another preferred embodiment, the alcohol is ethanol, and the reaction is carried out under the following conditions:

[0324] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in ethanol or a mixture of solvents with optional solvents;

[0325] b) Reacting carbon monoxide in the reactor, wherein the reaction is carried out at room temperature to 130°C;

[0326] c) End the reaction and separate the product.

[0327] In another preferred embodiment, the alcohol is propanol, and the reaction is carried out under the following conditions:

[0328] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid and butadiene in propanol or a mixture of propanol and optional solvent;

[0329] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0330] c) End the reaction and separate the product.

[0331] In another preferred embodiment, the alcohol is butanol, and the reaction is carried out under the following conditions:

[0332] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in butanol or a mixture thereof with an optional solvent.

[0333] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0334] c) End the reaction and separate the product.

[0335] In another preferred embodiment, the alcohol is octanol, and the reaction is carried out under the following conditions:

[0336] a) Dissolve palladium trifluoroacetate, phosphine ligand, acid, and butadiene in octanol or a mixture thereof with an optional solvent.

[0337] b) Carbon monoxide is introduced into the reactor to carry out the reaction, wherein the reaction is carried out at room temperature to 130°C;

[0338] c) End the reaction and separate the product.

[0339] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation

[0340] Based on long-term and in-depth research, the inventors have prepared a series of novel phosphine ligands and a method for synthesizing adipate esters by butadiene hydrogen esterification based on these ligands. This method can improve the catalytic efficiency of butadiene hydrogen esterification reaction, increase butadiene conversion and product selectivity, and the reaction conditions are mild and the operation is simple. Based on the above findings, the inventors have completed this invention.

[0341] definition

[0342] In this invention, "room temperature" refers to 10–30°C.

[0343] In this invention, the term "alkyl" refers to a straight-chain or branched saturated hydrocarbon group, preferably C10. 1-10 Alkyl groups (e.g., C15) 1-8 alkyl, C 1-6 alkyl, C 1-4 Alkyl groups).

[0344] In this invention, the term "cycloalkyl" refers to a saturated monocyclic ring, or a carbocyclic substituent comprising a fused, bridged, or spirocyclic polycyclic system, preferably C14. 3-8 cycloalkyl (e.g., C10) 3-6 (cycloalkyl groups).

[0345] In this invention, the term "alkoxy" refers to a cyclic or acyclic alkyl group connected by an oxygen bridge. The definitions of alkyl and cycloalkyl are as described above, and C10 is preferred. 1-10 alkoxy groups (e.g., C) 1-8 alkoxy, C 1-6 alkoxy, C 1-4 (alkoxy group).

[0346] Unless otherwise specified, in this invention, "aryl" refers to a group having 6-30 (preferably 6-14) ring carbon atoms and zero heteroatoms, a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 shared p electrons in a cyclic array), preferably C6-C. 14 Aryl, more preferably C6-C 10 Aryl).

[0347] Unless otherwise specified, in this invention, "heteroaryl" refers to a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 shared p electrons in a cyclic array) having 5-30 (preferably 5-20, more preferably 5-14) ring atoms (the ring atoms may be carbon atoms or heteroatoms), preferably 5-15-membered heteroaryl, more preferably 5-9-membered heteroaryl, wherein the heteroatoms are selected from the group consisting of O, N, and S.

[0348] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0349] The reagents and raw materials used in this invention are all commercially available.

[0350] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Percentages and parts are by weight unless otherwise stated.

[0351] Category 1: Cases involving Formula I ligands

[0352] Example 1

[0353] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L1 (6.2 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate, with a selectivity greater than 90% for the target product.

[0354] Example 2

[0355] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L2 (7.1 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 77% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0356] Example 3

[0357] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L3 (5.9 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a methyl adipate yield of 75% and a selectivity for the target product greater than 90%.

[0358] Example 4

[0359] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L4 (14.5 mg, 0.04 mmol), p-toluenesulfonic acid (17.2 mg, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a dimethyl adipate yield of 81%, with a target product selectivity greater than 90% (relative to the selectivity of the monohydroesterification product, the same below).

[0360] Example 5

[0361] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L5 (14.4 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 85% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0362] Example 6

[0363] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L6 (14.6 mg, 0.04 mmol), p-toluenesulfonic acid (17.2 mg, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a methyl adipate yield of 77% and a target product selectivity of 85%.

[0364] Example 7

[0365] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L7 (14.5 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (5 mL), tetrahydrofuran (10 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 78% for dibutyl adipate and a selectivity of 88% for the target product.

[0366] Example 8

[0367] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L8 (20.0 mg, 0.04 mmol), dodecyl sulfonic acid (26.1 mg, 0.08 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 79% for dimethyl adipate and a selectivity of 89% for the target product.

[0368] Example 9

[0369] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L9 (8.2 mg, 0.02 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), octanol (10 mL), n-hexane (10 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 83% for dioctyl adipate and a selectivity of 85% for the target product.

[0370] Example 10

[0371] Palladium acetate (2.2 mg, 0.01 mmol), bisphosphine ligand L10 (7.3 mg, 0.02 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 6 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 81%, with a selectivity for the target product greater than 90%.

[0372] Example 11

[0373] Palladium trifluoroacetate (0.3 mg, 0.001 mmol), bisphosphine ligand L12 (2.3 mg, 0.004 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 81%, with a selectivity for the target product greater than 90%.

[0374] Example 12

[0375] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L13 (7.8 mg, 0.02 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 80%, with a selectivity for the target product greater than 90%.

[0376] Example 13

[0377] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L14 (16.8 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 83%, with a selectivity for the target product greater than 90%.

[0378] Example 14

[0379] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L15 (17.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 82% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0380] Example 15

[0381] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L16 (12.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 75% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0382] Example 16

[0383] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L17 (15.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 73% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0384] Example 17

[0385] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L18 (12.9 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 75% for dimethyl adipate and a selectivity of 89% for the target product.

[0386] Example 18

[0387] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L19 (15.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 70% for dimethyl adipate and a selectivity of 85% for the target product.

[0388] Example 19

[0389] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L20 (17.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 76% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0390] Example 20

[0391] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L21 (15.6 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 91% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0392] Example 21

[0393] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L22 (18.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 90% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0394] Example 22

[0395] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L23 (18.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 88% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0396] Example 23

[0397] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), phosphine ligand L24 (16.3 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 85% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0398] Example 24

[0399] In a 300 mL Parr autoclave under nitrogen protection, Pd(CH3CN)4(BF4)2 (4.4 mg, 0.01 mmol), phosphine ligand L22 (18.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (10 mL), 1,4-dioxane (10 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 100 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 80%, with a selectivity of 88% for the target product.

[0400] Example 25

[0401] In a 300 mL Parr autoclave under nitrogen protection, Pd(hfacac)₂ (3.1 mg, 0.01 mmol), phosphine ligand L₂₂ (18.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (5 mL), tetrahydrofuran (15 mL), and a stir bar were added to displace carbon monoxide. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dibutyl adipate was 75%, with a selectivity of 87% for the target product.

[0402] Example 26

[0403] Palladium acetate (2.2 mg, 0.01 mmol), phosphine ligand L22 (18.4 mg, 0.04 mmol), p-toluenesulfonic acid (17.2 mg, 0.10 mmol), butadiene (5.4 g, 100 mmol), octanol (5 mL), tetrahydrofuran (15 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dioctyl adipate was 86%, with a selectivity for the target product greater than 90%.

[0404] Example 27

[0405] Pd₂(dba)₃ (4.6 mg, 0.005 mmol), phosphine ligand L₂₂ (18.4 mg, 0.04 mmol), trifluoroacetic acid (12 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 85% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0406] Example 28

[0407] Palladium trifluoroacetate (0.3 mg, 0.001 mmol), phosphine ligand L22 (18.4 mg, 0.04 mmol), methanesulfonic acid (1.0 μL, 0.016 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction, NMR analysis showed a yield of 88% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0408] Example 29

[0409] Palladium trifluoroacetate (0.03 mg, 0.0001 mmol), phosphine ligand L22 (18.4 mg, 0.04 mmol), methanesulfonic acid (0.3 μL, 0.004 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 48 hours. After the reaction, NMR analysis showed a yield of 80% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0410] Category II: Cases involving Formula II ligands

[0411] Example 1

[0412] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L1 (23.4 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a dimethyl adipate yield of 65% and a target product selectivity of 87% (relative to the selectivity of the monohydroesterification product, the same below).

[0413] Example 2

[0414] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L2 (23.4 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 92% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0415] Example 3

[0416] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L3 (22.4 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of methyl adipate was 70%, with a selectivity for the target product greater than 90%.

[0417] Example 4

[0418] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L4 (20.0 mg, 0.04 mmol), p-toluenesulfonic acid (17.2 mg, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 82%, with a selectivity of 76% for the target product.

[0419] Example 5

[0420] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L5 (26.32 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a 90% yield of dimethyl adipate and a 85% selectivity for the target product.

[0421] Example 6

[0422] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L6 (20.2 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a methyl adipate yield of 75% and a target product selectivity of 85%.

[0423] Example 7

[0424] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L8 (10.8 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 76% for dimethyl adipate and a selectivity of 83% for the target product.

[0425] Example 8

[0426] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L9 (20.0 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 83% for dimethyl adipate and a selectivity of 85% for the target product.

[0427] Example 9

[0428] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L10 (26.2 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 87% for dimethyl adipate and a selectivity of 85% for the target product.

[0429] Example 10

[0430] Palladium acetate (2.2 mg, 0.01 mmol), bisphosphine ligand L11 (19.1 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the autoclave pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 6 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 75% for dimethyl adipate and a selectivity of 67% for the target product.

[0431] Example 11

[0432] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L12 (11.6 mg, 0.02 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 78% for dimethyl adipate and a selectivity of 65% for the target product.

[0433] Example 12

[0434] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L14 (29.8 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The autoclave pressure was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 85% for the target product.

[0435] Example 13

[0436] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L15 (25.6 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 90%, with a selectivity for the target product greater than 90%.

[0437] Example 14

[0438] To a 300 mL Parr autoclave, under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L16 (26.8 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 90%, with a selectivity for the target product greater than 90%.

[0439] Example 15

[0440] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L17 (30.6 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 87% for dimethyl adipate, with a selectivity for the target product greater than 90%.

[0441] Example 16

[0442] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L18 (31.1 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 92%, with a selectivity for the target product greater than 90%.

[0443] Example 17

[0444] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L19 (36.0 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 85%, with a selectivity for the target product greater than 90%.

[0445] Example 18

[0446] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L20 (27.1 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 90%, with a selectivity for the target product greater than 90%.

[0447] Example 19

[0448] Palladium chloride (1.8 mg, 0.01 mmol), bisphosphine ligand L2 (11.7 mg, 0.02 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), ethanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 100 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 90% for diethyl adipate and a selectivity greater than 90% for the target product.

[0449] Example 20

[0450] Palladium trifluoroacetate (0.3 mg, 0.001 mmol), bisphosphine ligand L2 (2.3 mg, 0.004 mmol), methanesulfonic acid (1.0 μL, 0.016 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 100 °C and stirred for 48 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 90%, with a selectivity for the target product greater than 90%.

[0451] Example 21

[0452] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (0.03 mg, 0.0001 mmol), bisphosphine ligand L2 (0.6 mg, 0.001 mmol), methanesulfonic acid (0.13 μL, 0.002 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 100 °C and stirred for 48 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 76% for dimethyl adipate, with a selectivity for the target product greater than 90%.

[0453] Example 22

[0454] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L2 (23.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (54 g, 1 mol), methanol (30 mL), toluene (30 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 48 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 95% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0455] Example 23

[0456] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L2 (2.3 mg, 0.004 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dibutyl adipate was 90%, with a selectivity of 90% for the target product.

[0457] Example 24

[0458] Palladium acetate (11.2 mg, 0.05 mmol), bisphosphine ligand L2 (23.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), propanol (10 mL), n-hexane (10 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction, NMR analysis showed a yield of 84% for dipropyl adipate and a selectivity greater than 90% for the target product.

[0459] Example 25

[0460] Pd₂(dba)₃ (4.6 mg, 0.005 mmol), bisphosphine ligand L₂ (23.4 mg, 0.04 mmol), trifluoroacetic acid (12 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), octanol (10 mL), tetrahydrofuran (10 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 86% for dioctyl adipate, with a selectivity greater than 90% for the target product.

[0461] Category 3: Cases involving V-ligands

[0462] Example 1

[0463] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L1 (15.1 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of methyl adipate of 87%, with a selectivity for the target product greater than 90% (relative to the selectivity of the monohydroesterification product, the same below).

[0464] Example 3

[0465] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L2 (14.6 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 78% for dimethyl adipate, with a selectivity greater than 90% for the target product.

[0466] Example 4

[0467] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L3 (15.2 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 79% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0468] Example 5

[0469] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L4 (16.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 77% for dimethyl adipate and a selectivity of 87% for the target product.

[0470] Example 6

[0471] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L5 (20.1 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), ethanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 77% for diethyl adipate and a selectivity greater than 90% for the target product.

[0472] Example 7

[0473] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L6 (21.8 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), ethanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 82% for diethyl adipate and a selectivity greater than 90% for the target product.

[0474] Example 8

[0475] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L7 (24.1 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (10 mL), 1,4-dioxane (10 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dibutyl adipate was 75%, with a selectivity for the target product greater than 90%.

[0476] Example 9

[0477] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L9 (1.7 mg, 0.004 mmol), dodecyl sulfonic acid (26.1 mg, 0.08 mmol), butadiene (5.4 g, 100 mmol), butanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the autoclave pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 82% for dibutyl adipate and a selectivity of 88% for the target product.

[0478] Example 10

[0479] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L11 (19.6 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), propanol (10 mL), n-hexane (10 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction, NMR analysis showed that the yield of dipropyl adipate was 80%, and the selectivity for the target product was greater than 90%.

[0480] Example 11

[0481] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L12 (21.9 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), octanol (10 mL), tetrahydrofuran (10 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 79% for dioctyl adipate, with a selectivity for the target product greater than 90%.

[0482] Example 12

[0483] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L13 (10.4 mg, 0.02 mmol), p-toluenesulfonic acid (17.5 mg, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (10 mL), tetrahydrofuran (10 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 60 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 85% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0484] Example 13

[0485] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L14 (13.4 mg, 0.02 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), propanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dipropyl adipate was 80%, with a selectivity of 85% for the target product.

[0486] Example 14

[0487] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L15 (20.9 mg, 0.04 mmol), trifluoroacetic acid (12 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (10 mL), n-hexane (10 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 87% for the target product.

[0488] Example 15

[0489] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L16 (19.1 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), octanol (10 mL), acetone (10 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 83% for dioctyl adipate, with a selectivity for the target product greater than 90%.

[0490] Example 16

[0491] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L18 (18.7 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (10 mL), tetrahydrofuran (10 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 73% for dibutyl adipate and a selectivity of 86% for the target product.

[0492] Example 17

[0493] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L19 (20.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), propanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the autoclave pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 76% for dipropyl adipate and a selectivity of 88% for the target product.

[0494] Example 18

[0495] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L20 (29.5 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 74% for dimethyl adipate and a selectivity of 89% for the target product.

[0496] Example 19

[0497] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L21 (27.3 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (10 mL), tetrahydrofuran (10 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dibutyl adipate was 78%, with a selectivity of 88% for the target product.

[0498] Example 20

[0499] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L23 (26.3 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), propanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the autoclave pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 76% for dipropyl adipate and a selectivity of 87% for the target product.

[0500] Example 21

[0501] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L25 (28.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dibutyl adipate was 88%, with a selectivity for the target product greater than 90%.

[0502] Example 22

[0503] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L26 (19.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 74% for dimethyl adipate, with a selectivity greater than 90% for the target product.

[0504] Example 23

[0505] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L30 (18.8 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 86%, with a selectivity for the target product greater than 90%.

[0506] Example 24

[0507] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L33 (17.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 93% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0508] Example 25

[0509] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L36 (23.8 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the autoclave pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 90% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0510] Example 26

[0511] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L38 (19.5 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 82% for dimethyl adipate and a selectivity of 87% for the target product.

[0512] Example 27

[0513] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L39 (24.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 85% for the target product.

[0514] Example 28

[0515] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L41 (24.3 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 89% for dimethyl adipate and a selectivity of 88% for the target product.

[0516] Example 28

[0517] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L42 (26.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 91% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0518] Example 29

[0519] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L44 (26.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 90%, with a selectivity for the target product greater than 90%.

[0520] Example 30

[0521] Palladium trifluoroacetate (0.3 mg, 0.001 mmol), bisphosphine ligand L33 (2.0 mg, 0.004 mmol), methanesulfonic acid (1.0 μL, 0.016 mmol), butadiene (54 g, 1 mol), methanol (50 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 48 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a 91% yield of dimethyl adipate and a selectivity greater than 90% for the target product.

[0522] Example 31

[0523] Palladium trifluoroacetate (0.03 mg, 0.0001 mmol), bisphosphine ligand L33 (0.2 mg, 0.0004 mmol), methanesulfonic acid (0.5 μL, 0.008 mmol), butadiene (54 g, 1 mol), butanol (30 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 48 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 85% for dibutyl adipate, with a selectivity for the target product greater than 90%.

[0524] Example 32

[0525] Palladium acetate (2.2 mg, 0.01 mmol), bisphosphine ligand L33 (17.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the autoclave pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 87% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0526] Example 33

[0527] Pd(dba)₂ (5.7 mg, 0.01 mmol), bisphosphine ligand L33 (17.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 85%, with a selectivity for the target product greater than 90%.

[0528] Category 4: Cases involving type VI ligands

[0529] Example 1

[0530] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L1 (19.4 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a dimethyl adipate yield of 85% and a target product selectivity of 82% (relative to the selectivity of the monohydroesterification product, the same below).

[0531] Example 2

[0532] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L2 (19.6 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 80%, and the selectivity for the target product was 74%.

[0533] Example 3

[0534] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L3 (19.5 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 77%, and the selectivity for the target product was 75%.

[0535] Example 4

[0536] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L4 (11.7 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 78%, and the selectivity for the target product was 75%.

[0537] Example 5

[0538] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L5 (19.4 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 75%, and the selectivity for the target product was 75%.

[0539] Example 6

[0540] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L6 (19.4 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 78%, and the selectivity for the target product was 75%.

[0541] Example 7

[0542] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L9 (18.3 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 82%, and the selectivity for the target product was 80%.

[0543] Example 8

[0544] Pd₂(dba)₃ (4.6 mg, 0.005 mmol), bisphosphine ligand L10 (12.8 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 85%, and the selectivity for the target product was 75%.

[0545] Example 9

[0546] Pd(dba)₂ (5.7 mg, 0.01 mmol), bisphosphine ligand L11 (13.5 mg, 0.02 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 80%, and the selectivity for the target product was 75%.

[0547] Example 10

[0548] Palladium acetate (2.2 mg, 0.01 mmol), bisphosphine ligand L12 (29.2 mg, 0.04 mmol), dodecyl sulfonic acid (26.1 mg, 0.08 mmol), methanol (50 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 76% for the target product.

[0549] Example 11

[0550] Pd(hfacac)₂ (3.1 mg, 0.01 mmol), bisphosphine ligand L13 (28.1 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), methanol (30 mL), n-hexane (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of dimethyl adipate was 74%, and the selectivity for the target product was 75%.

[0551] Example 12

[0552] In a 300 mL Parr autoclave under nitrogen protection, Pd(CH3CN)4(BF4)2 (4.4 mg, 0.01 mmol), bisphosphine ligand L14 (15.7 mg, 0.02 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), propanol (30 mL), acetonitrile (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added to displace carbon monoxide gas. The autoclave was then pressurized to 4.0 MPa. The temperature was rapidly increased to 120 °C, and the reaction was stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of propyl adipate was 78%, and the selectivity for the target product was 75%.

[0553] Example 13

[0554] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L15 (30.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butanol (30 mL), toluene (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis revealed a yield of 70% for butyl adipate and a selectivity of 82% for the target product.

[0555] Example 14

[0556] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L16 (22.8 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butanol (30 mL), toluene (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis revealed a yield of butyl adipate of 88% and a selectivity for the target product greater than 90%.

[0557] Example 15

[0558] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L17 (32.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butanol (30 mL), toluene (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was then purged to bring the autoclave pressure to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis revealed a yield of butyl adipate of 84% and a selectivity for the target product greater than 90%.

[0559] Example 16

[0560] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L18 (22.8 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butanol (30 mL), toluene (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis revealed a yield of butyl adipate of 88% and a selectivity for the target product greater than 90%.

[0561] Example 17

[0562] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L19 (27.1 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butanol (30 mL), toluene (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis revealed a yield of butyl adipate of 87% and a selectivity for the target product greater than 90%.

[0563] Example 18

[0564] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L20 (24.2 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butanol (30 mL), toluene (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was then purged to bring the autoclave pressure to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of butyl adipate was 90%, and the selectivity for the target product was greater than 90%.

[0565] Example 19

[0566] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (0.3 mg, 0.001 mmol), bisphosphine ligand L16 (2.3 mg, 0.004 mmol), p-toluenesulfonic acid (0.9 mg, 0.005 mmol), ethanol (30 mL), tetrahydrofuran (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was then displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis showed that the yield of ethyl adipate was 87%, and the selectivity for the target product was greater than 90%.

[0567] Example 17

[0568] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (0.03 mg, 0.0001 mmol), bisphosphine ligand L16 (0.5 mg, 0.0008 mmol), methanesulfonic acid (0.07 μL, 0.001 mmol), octanol (30 mL), tetrahydrofuran (20 mL), butadiene (5.4 g, 100 mmol), and a stir bar were added. Carbon monoxide was displaced, and the autoclave pressure was increased to 4.0 MPa. The mixture was rapidly heated to 120 °C and stirred for 48 hours. After the reaction was complete, the temperature was lowered, and an internal standard was added. NMR analysis revealed a yield of octyl adipate of 80% and a selectivity for the target product greater than 90%.

[0569] Fifth category: Cases involving formula VIII ligands

[0570] Example 1

[0571] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L1 (25.2 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 65% for dimethyl adipate and a target product selectivity of 87% (relative to the selectivity of the monohydroesterification product, the same below).

[0572] Example 2

[0573] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L2 (19.0 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 92% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0574] Example 3

[0575] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L3 (19.5 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of methyl adipate of 70% and a selectivity for the target product greater than 90%.

[0576] Example 4

[0577] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L4 (19.0 mg, 0.04 mmol), p-toluenesulfonic acid (17.2 mg, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 82% for dimethyl adipate and a selectivity of 76% for the target product.

[0578] Example 5

[0579] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L5 (19.0 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 90% for dimethyl adipate and a selectivity of 85% for the target product.

[0580] Example 6

[0581] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L6 (9.8 mg, 0.02 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a methyl adipate yield of 75% and a target product selectivity of 85%.

[0582] Example 7

[0583] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L8 (19.0 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 76% for dimethyl adipate and a selectivity of 83% for the target product.

[0584] Example 8

[0585] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L9 (10.5 mg, 0.02 mmol), dodecyl sulfonic acid (26.1 mg, 0.08 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 83% for dimethyl adipate and a selectivity of 85% for the target product.

[0586] Example 9

[0587] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L10 (19.7 mg, 0.04 mmol), methanesulfonic acid (6.5 μL, 0.10 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 87% for dimethyl adipate and a selectivity of 85% for the target product.

[0588] Example 10

[0589] Palladium acetate (2.2 mg, 0.01 mmol), bisphosphine ligand L11 (21.0 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 6 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 75% for dimethyl adipate and a selectivity of 67% for the target product.

[0590] Example 11

[0591] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L12 (19.1 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 78% for dimethyl adipate and a selectivity of 68% for the target product.

[0592] Example 12

[0593] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L13 (9.5 mg, 0.02 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 85% for the target product.

[0594] Example 13

[0595] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L14 (9.6 mg, 0.02 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 85% for the target product.

[0596] Example 14

[0597] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L15 (9.5 mg, 0.02 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 85% for the target product.

[0598] Example 15

[0599] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L16 (9.7 mg, 0.02 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 85% for the target product.

[0600] Example 16

[0601] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L17 (18.0 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 81%, with a selectivity of 85% for the target product.

[0602] Example 17

[0603] To a 300 mL Parr autoclave under nitrogen protection, palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L18 (20.2 mg, 0.04 mmol), trifluoromethanesulfonic acid (14.2 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 81% for dimethyl adipate and a selectivity of 85% for the target product.

[0604] Example 18

[0605] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L20 (21.8 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 70% for dimethyl adipate and a selectivity of 85% for the target product.

[0606] Example 19

[0607] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L21 (18.9 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 83% for dimethyl adipate and a selectivity of 88% for the target product.

[0608] Example 20

[0609] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L22 (24.4 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 87% for dimethyl adipate and a selectivity of 88% for the target product.

[0610] Example 21

[0611] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L23 (26.6 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed a yield of 90% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0612] Example 22

[0613] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L24 (22.3 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 90%, with a selectivity for the target product greater than 90%.

[0614] Example 23

[0615] Palladium trifluoroacetate (3.3 mg, 0.01 mmol), bisphosphine ligand L25 (33.7 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 80%, with a selectivity for the target product greater than 90%.

[0616] Example 24

[0617] In a 300 mL Parr autoclave under nitrogen protection, Pd(CH3CN)4(BF4)2 (4.4 mg, 0.01 mmol), bisphosphine ligand L24 (22.3 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (10 mL), 1,4-dioxane (10 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 100 °C and stirred for 24 hours. After the reaction was completed, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 80%, and the selectivity for the target product was 86%.

[0618] Example 25

[0619] In a 300 mL Parr autoclave under nitrogen protection, Pd(hfacac)₂ (3.1 mg, 0.01 mmol), bisphosphine ligand L24 (22.3 mg, 0.04 mmol), methanesulfonic acid (10.4 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), butanol (5 mL), tetrahydrofuran (15 mL), and a stir bar were added to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dibutyl adipate was 80%, with a selectivity of 87% for the target product.

[0620] Example 26

[0621] Palladium acetate (2.2 mg, 0.01 mmol), bisphosphine ligand L24 (22.3 mg, 0.04 mmol), p-toluenesulfonic acid (17.2 mg, 0.10 mmol), butadiene (5.4 g, 100 mmol), octanol (5 mL), tetrahydrofuran (15 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis revealed a yield of 76% for dioctyl adipate and a selectivity of 88% for the target product.

[0622] Example 27

[0623] Pd₂(dba)₃ (4.6 mg, 0.005 mmol), L₂₄ (22.3 mg, 0.04 mmol), trifluoroacetic acid (12 μL, 0.16 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection to displace carbon monoxide gas. The pressure inside the autoclave was then increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction was complete, the temperature was lowered, and NMR analysis showed that the yield of dimethyl adipate was 75%, with a selectivity of 86% for the target product.

[0624] Example 28

[0625] Palladium trifluoroacetate (0.3 mg, 0.001 mmol), L24 (2.2 mg, 0.004 mmol), methanesulfonic acid (1.0 μL, 0.016 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the pressure inside the autoclave was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction, NMR analysis showed a yield of 90% for dimethyl adipate and a selectivity greater than 90% for the target product.

[0626] Example 29

[0627] Palladium trifluoroacetate (0.03 mg, 0.0001 mmol), L24 (0.6 mg, 0.001 mmol), methanesulfonic acid (0.3 μL, 0.004 mmol), butadiene (5.4 g, 100 mmol), methanol (20 mL), and a stir bar were added to a 300 mL Parr autoclave under nitrogen protection. Carbon monoxide gas was then displaced, and the autoclave pressure was increased to 4 MPa. The mixture was rapidly heated to 120 °C and stirred for 24 hours. After the reaction, NMR analysis showed a dimethyl adipate yield of 85% and a selectivity for the target product greater than 90%.

[0628] The phosphine ligands of the present invention can produce adipate products in high yields (>75%, >68% in the best example) with good selectivity when used for catalytic preparation of adipate esters, and therefore have potential industrial applications.

[0629] Furthermore, the phosphine ligands of the present invention exhibit good catalytic conversion rates, thus enabling catalytic conversion at low dosages (<10). -4 Equivalent, preferably <10 -5 Equivalent, preferably <10 -6 The catalytic reaction is completed in equivalent quantities.

[0630] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for synthesizing adipate by palladium-catalyzed hydrogen esterification of butadiene, characterized in that, The method includes the following steps: a) In a reaction vessel, the palladium catalyst, phosphine ligand, acid and butadiene are dissolved in alcohol and optional solvent; b) Introduce carbon monoxide into the reactor to carry out the reaction; c) End the reaction and separate the product; The ligands are selected from Formula I, Formula II, Formula V, Formula VI, and Formula VIII; The phosphine ligands of Formula I have structures selected from the group shown below; in, R 1 Selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-12 cycloalkyl, substituted or unsubstituted C 6-30 Aryl; R 2 Selected from the following group: substituted or unsubstituted 5-20 member heteroaryl groups; R 3 C is hydrogen, substituted or unsubstituted 1-10 Alkyl, substituted or unsubstituted C 1-10 Alkoxy, substituted or unsubstituted C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 Alkyl), nitro, substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-30 membered heteroaryl; or two R atoms located on adjacent carbon atoms 3 The carbon atoms bonded to it together form a group selected from the following group: C 6- 10 Aryl, 5-12 heteroaryl; In the ligands described, A is either substituted or unsubstituted C. 1-4 Alkylene Or the aforementioned A and Together in, This is the connection point connected to P; Among them, R 4 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 quinone heteroaryl; or with R 3 One or more ring atoms on the pyridine ring together form a 5-7 membered carbon ring or heterocycle; Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 heteroaryl; The phosphine ligands of Formula II have structures selected from the group shown below; in, R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-12 Cycloalkyl, substituted or unsubstituted 3-12 membered heterocyclic alkyl, substituted or unsubstituted C 6-30 Aryl; R 2 and R 3 Each is an independent substituted or unsubstituted 5-20 heteroaryl group; A is selected from the following group: Among them, R 5 R 6 R 7 R 8 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 R 6 R 7 R 8 The ring atoms attached to it together form a 5-7 membered carbon ring or heterocycle; Y is one of O, NH or S; Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 heteroaryl; The phosphine ligands of formula V have structures selected from the group shown below: in, R 1 Selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30 Aryl; and R 2 Selected from the following group: substituted or unsubstituted 5-20 membered heteroaryl groups; or R 1 Selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30 Aryl; and R 2 Selected from the following group: substituted or unsubstituted C 6-30 Aryl; R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 Each is independently selected from the following group: hydrogen, hydroxyl, halogen, substituted or unsubstituted C. 1-12 Alkyl, substituted or unsubstituted C 3-12 cycloalkyl, substituted or unsubstituted C 3-10 Heterocyclic alkyl, substituted or unsubstituted C 2-10 alkenyl, substituted or unsubstituted C 6-30 aryl, substituted or unsubstituted C 5-20 heteroaryl, C 1-10 Alkoxy, C 1-10 Alkylamino, C 1-10 Alkyl thio; R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 Any two of them, together with the carbon atoms they are attached to, form a 4-8 membered carbon ring or a heterocycle; A is -L 1 -A 1 -L 2 -, where L 1 A 1 and L 2 Each is independently selected from the following groups: chemical bond, O, NH, S, substituted or unsubstituted C. 1-12 Alkyl, substituted or unsubstituted C 3-8 cycloalkyl, substituted or unsubstituted C 3-8 Heterocyclic alkyl, substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-20 membered heteroaryl, substituted or unsubstituted biphenyl, substituted or unsubstituted Replaced or not replaced And L 1 A 1 and L 2 Not simultaneously without chemical bonds; wherein, when the aryl (including phenyl) or heteroaryl is replaced by two or more substituents, any two substituents can together with the ring atom attached to them form a 4-8 membered carbon ring or heterocycle; M is Fe, Co or Ru; B is selected from the following group: substituted or unsubstituted methylene, ethylene, C=CHR, C=NR, hydroxymethyl, carbonyl, thiocarbonyl. -C(O)-C(O)-; where R is a substituted or unsubstituted C 1-10 Alkyl, or substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-20 membered heteroaryl; R 11 R 12 Each of the following is selected independently: H, OH, substituted or unsubstituted C 1-10 alkyl, or It constitutes a 5-8 membered heterocycle, and the heterocycle may be substituted or unsubstituted; X represents O or S; Z represents O, S, or NH. Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 membered heteroaryl, benzyl, -CH(Ph)2; The phosphine ligands shown in Formula VI have structures selected from the group shown below; in, R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30 Aryl; R 2 and R 3 Each is independently selected from the group consisting of substituted or unsubstituted 5-20 heteroaryl groups; R 5 R 6 Each is an independent substituent located on the corresponding ring and selected from the following groups: H, C 1- 10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 R 6 The ring atoms connected to it together form a 5-7 membered carbon ring or heterocycle, wherein the heterocycle may have 1-3 heteroatoms selected from the group consisting of N, O or S; Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 membered heteroaryl, halogen, haloalkyl, benzyl; The phosphine ligands of formula VIII have structures selected from the group below; in, R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted C 6-30 Aryl; R 2 and R 3 Each is independently selected from the group consisting of substituted or unsubstituted 5-20 heteroaryl groups; A represents unsubstituted or unreplaced by one or more R's. 6 The substituted 5-10-membered heteroaryl group, wherein the heteroatom in the heteroaryl group is one or more of O, N, and S, and may be the same or different; R 5 and R 6 Each is an independent substituent located on the corresponding ring and selected from the following groups: H, C 1- 10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 The ring atoms attached to it together form 5-7 membered carbon rings or heterocycles; Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 quinone heteroaryl, halogen, haloalkyl.

2. The method as described in claim 1, characterized in that, In the ligand of formula I, A is CH2 or Or the aforementioned A and Together in, This is the connection point connected to P; Among them, R 4 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl).

3. The method as described in claim 1, characterized in that, In the ligands of Formula I, R 1 Selected from the following group: substituted or unsubstituted C 1-10 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl groups; R 2 Selected from the following group: substituted or unsubstituted 5-10 member heteroaryl groups; R 3 For hydrogen, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, trialkylsilyl group (wherein the alkyl group is C10) 1-4 Alkyl), nitro, -CH(Ph)2, C 6-30 Aryl, 5-10 heteroaryl.

4. The method as described in claim 1, characterized in that, In the ligands of Formula I, R 1 Selected from the group consisting of: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, or phenyl; R 2 Selected from the group consisting of: pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroloyl, imidazolyl, pyrazolyl, thiophenyl, furanyl, thiazolyl, and triazolyl; and wherein the R... 2 It may optionally be substituted by one or more substituents selected from the following group: C 1-4 alkyl; R 3 Selected from the following group: methyl, n-propyl, isopropyl, tert-butyl, methoxy, cyano, COOH, -CH(Ph)2, benzenesulfonyl, trimethylsilyl.

5. The method as described in claim 1, characterized in that, The ligands of Formula I are selected from the following group:

6. The method as described in claim 1, characterized in that, The amount of the phosphine ligand of Formula I is 0.00001 to 10% molar equivalent of the butadiene.

7. The method as described in claim 1, characterized in that, When the phosphine ligand of Formula I is a bisphosphine ligand (i.e., the compound of Formula I), the molar ratio of the palladium catalyst to the bisphosphine ligand is 1:0.5 to 1:

30.

8. The method as described in claim 1, characterized in that, In the ligands of formula II, R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-4 Alkyl, substituted or unsubstituted C 3- 10 Cycloalkyl (adamantane), phenyl; R 2 and R 3 Each is independently selected from the following group: substituted or unsubstituted 5-10 heteroaryl groups; Unless otherwise specified, the substitution refers to the substitution of one or more hydrogen atoms on the group by a substituent selected from the group consisting of: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C10). 1-4 alkyl), nitro, C 6-30 Aryl, 5-30 heteroaryl.

9. The method as described in claim 1, characterized in that, In the ligands of formula II, R 1 and R 4 Each of the following is independently selected: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl or phenyl; R 2 and R 3 Each of the following groups is independently selected: pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroleyl, imidazolyl, pyrazolyl, thiopheneyl, furanyl, thiazolyl, triazolyl; and / or R 5 R 6 R 7 R 8 These are one or more substituents selected from the following group located on the corresponding ring: H, C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-10 aryl, 5-10 membered heteroaryl; or two R atoms located on adjacent ring atoms 5 R 6 R 7 R 8 The ring atoms attached to it together form 5-7 membered carbon rings or heterocycles.

10. The method as described in claim 1, characterized in that, The ligands of Formula II are selected from the following group:

11. The method as described in claim 1, characterized in that, The amount of the phosphine ligand of Formula II is 0.00001 to 10% molar equivalent of the butadiene.

12. The method as described in claim 1, characterized in that, When the phosphine ligand of Formula II is a bisphosphine ligand (i.e., the compound of Formula II), the molar ratio of the palladium catalyst to the bisphosphine ligand is 1:0.5 to 1:

30.

13. The method as described in claim 1, characterized in that, In the ligands of formula V, R 1 Selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C 6-20 Aryl; R 2 Selected from the following group: substituted or unsubstituted 5-12 heteroaryl groups; or R 1 Selected from the following group: substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted C 3-10 cycloalkyl; and R 2 C is selected from the group consisting of substituted or unsubstituted C. 6-20 Aryl.

14. The method as described in claim 1, characterized in that, In the ligand of formula V, R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 Each is independently selected from the following group: hydrogen, substituted or unsubstituted C. 1-12 Alkyl, substituted or unsubstituted C 3-12 cycloalkyl, substituted or unsubstituted C 3-10 Heterocyclic alkyl, substituted or unsubstituted C 2-10 alkenyl, C 1-10 Alkoxy, C 1-10 Alkylamino, C 1-10 alkyl thio; or R 3 R 10 The carbon atoms attached to it together form 4-8 membered carbon rings or heterocycles; B is selected from the following group: substituted or unsubstituted methylene, ethylene, =NR, hydroxymethyl, carbonyl. -C(O)-C(O)-; where R is a substituted or unsubstituted C 1-10 Alkyl, or phenyl; R 11 R 12 Each of the following is selected independently: H, OH, substituted or unsubstituted C 1-6 alkyl, or It constitutes a 5-8 membered heterocycle, and the heterocycle may be unsubstituted or C-substituted. 1-6 Alkyl-substituted; X represents O and S.

15. The method as described in claim 1, characterized in that, In the ligand of formula V, L 1 Selected from the following group: C with no chemical bond, chemical bond, substituted or unsubstituted. 1-6 Alkyl groups; A 1 and L 2 Each is independently selected from the following groups: chemical bonds, substituted or unsubstituted C. 1-6 Alkyl, substituted or unsubstituted C3-8 cycloalkyl, substituted or unsubstituted C 3-8 Heterocyclic alkyl, substituted or unsubstituted C 6- 10 Aryl, substituted or unsubstituted 5-10-membered heteroaryl, substituted or unsubstituted biphenyl, substituted or unsubstituted ferrocene; substituted or unsubstituted Z represents O or S; or A 1 For O, NH, S, and L 1 and L 2 Each is independently selected from the following group: substituted or unsubstituted C 6-10 Aryl, substituted or unsubstituted 5-10 heteroaryl groups.

16. The method as described in claim 1, characterized in that, In the ligands of formula V, A is a structure selected from the following group: Among them, R 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 R 24 R 25 These are one or more substituents selected from the following group located on the corresponding ring: C 1-10 Alkyl, C 1-10 Alkoxy, C 2-10 Ester group, cyano group, COOH group, benzenesulfonyl group, trialkylsilyl group (wherein the alkyl group is C 1-4 alkyl), nitro, C 6-30 aryl, 5-30 membered heteroaryl; or two R atoms located on adjacent ring atoms 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 The ring atoms attached to it together form 5-7 membered carbon rings or heterocycles; x is selected from 0, 1, 2, 3, 4 or 5; m and n are 0, 1, 2, and 3 respectively; M is Fe, Co, or Ru; Z is O, S, or NH; V, W, and Y are either N or CH, and may be the same or different; and the hydrogen atom on CH can be R. 18 replace; Selected from the following group: Among them, Ar 1 Selected from substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted 5-20 heteroaryl groups.

17. The method as described in claim 1, characterized in that, The ligands of formula V are selected from the following group:

18. The method as described in claim 1, characterized in that, The amount of the phosphine ligand of formula V is 0.00001 to 10% molar equivalent of the butadiene.

19. The method as described in claim 1, characterized in that, In the ligands of formula VI, R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-4 Alkyl, substituted or unsubstituted C 3- 6-cycloalkyl, substituted or unsubstituted C 6-14 Aryl; R 2 and R 3 Each is independently selected from the following group: substituted or unsubstituted 5-20 heteroaryl groups; Wherein, the R 1 R 2 R 3 and R 4 Each is independently unsubstituted or substituted by 1-2 substituents selected from the group consisting of: methyl, methoxy, cyano, COOH, benzenesulfonyl, trimethylsilyl, halogen, haloalkyl, benzyl.

20. The method as described in claim 1, characterized in that, In the ligands of formula VI, R 1 and R 4 Each of the following is independently selected: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl or adamantyl; R 2 and R 3 Each of the following groups is independently substituted or unsubstituted: pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroleyl, imidazolyl, pyrazolyl, thiopheneyl, furanyl, thiazolyl, triazolyl.

21. The method as described in claim 1, characterized in that, The ligands of formula VI are selected from the following group:

22. The method as described in claim 1, characterized in that, The amount of the phosphine ligand of Formula VI is 0.00001 to 10% molar equivalent of the butadiene.

23. The method of claim 1, wherein when the phosphine ligand of formula VI is a bisphosphine ligand (i.e., the compound of formula VI), the molar ratio of the palladium catalyst to the bisphosphine ligand is 1:1 to 1:

30.

24. The method as described in claim 1, characterized in that, In the ligands of formula VIII, R 1 and R 4 Each is independently selected from the following group: substituted or unsubstituted C 1-4 Alkyl, substituted or unsubstituted C 3- 10 cycloalkyl, phenyl; R 2 and R 3 Each is independently selected from the following group: substituted or unsubstituted 5-20 heteroaryl groups; Wherein, the R 1 R 2 R 3 and R 4 Each is independently unsubstituted or substituted by 1-2 substituents selected from the group consisting of: methyl, methoxy, cyano, COOH, benzenesulfonyl, trimethylsilyl, halogen, and haloalkyl.

25. The method as described in claim 1, characterized in that, In the ligands of formula VIII, R 1 and R 4 Each of the following is independently selected: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl or phenyl; R 2 and R 3 Each of the following groups is independently substituted or unsubstituted: pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroleyl, imidazolyl, pyrazolyl, thiopheneyl, furanyl, thiazolyl, triazolyl.

26. The method as described in claim 1, characterized in that, The ligands of formula VIII are selected from the following group:

27. The method as described in claim 1, characterized in that, The amount of the phosphine ligand of Formula VIII is 0.00001 to 10% molar equivalent of the butadiene.

28. The method as described in claim 1, characterized in that, The alcohol is C 1-12 Alkyl alcohols; preferably, the alcohols are selected from the group consisting of methanol, ethanol, propanol, butanol, octanol, or combinations thereof.

29. The method as described in claim 1, characterized in that, The palladium catalyst is selected from the group consisting of palladium acetate, palladium trifluoroacetate, palladium pentavalerate, palladium tetrafluoroborate tetraacetonitrile, palladium hexafluoroacetylacetonate, bis(acetylacetonate)palladium, palladium tetraacetonitrile trifluoromethanesulfonate, palladium neopentanoate, bis(dibenzylacetonate)palladium, tri(dibenzylacetonate)palladium, palladium chloride, (1,5-cyclooctadiene)palladium dichloride, palladium diacetonitrile dichloride, palladium dibenzonitrile dichloride, or combinations thereof.

30. The method as described in claim 1, characterized in that, The acid is selected from the group consisting of: perchloric acid, sulfuric acid, phosphoric acid, sulfonic acid, alkyl phosphoric acid, alkyl sulfonic acid, alkyl carboxylic acid, perfluoroalkyl sulfonic acid, perfluoroalkyl carboxylic acid, and aryl sulfonic acid.

31. The method as described in claim 1, characterized in that, The solvent is selected from the group consisting of alkane solvents, substituted aromatic solvents, ether solvents, ketone solvents, nitrile solvents, ester solvents, or combinations thereof.

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