A diphosphine ligand, a method for preparing the same, a catalyst composition for a hydroesterification reaction, and a method for preparing an organic carboxylate

Abstract

The present application relates to the field of catalysts for hydroesterification reaction, and discloses a diphosphine ligand and a preparation method thereof, a catalyst composition for hydroesterification reaction, and a preparation method of organic carboxylic acid ester. The ligand has a structure shown in formula (I); in formula (I), R1 and R2 are each independently selected from one of methyl, ethyl, phenyl and tert-butyl, and X is selected from one of -CH2- and -O-. The diphosphine ligand provided by the present application has the advantages of simple and readily available raw materials, simple synthesis method, excellent catalytic activity in the reaction of olefin hydroesterification for synthesizing organic carboxylic acid ester, high reaction conversion rate and selectivity, high product yield, low production cost, high economic efficiency and high industrial application value.

Description

Technical Field

[0001] This invention relates to the field of catalysts for hydrogen esterification reactions, specifically to a diphosphine ligand and its preparation method, a catalyst composition for hydrogen esterification reactions, and a method for preparing organic carboxylic acid esters. Background Technology

[0002] Organic carboxylic acid esters are an important class of organic compounds, widely used in fine chemicals, pharmaceuticals, pesticides, food additives, fragrances, coatings, and paints. For example, isononanoic acid esters are widely used as solvents and additives in the cosmetics and animal feed industries. Furthermore, isononanoic acid esters are important chemical intermediates; through hydrolysis, they can be converted into isononanoic acid, which is also an important organic chemical raw material with good solubility, stability, and low-temperature performance, and is widely used in coatings, lubricants, dyes, and plastics.

[0003] Olefin hydrogenation is a process in which olefins, carbon monoxide, and alcohols react in a one-step manner under the action of metal compounds / phosphine ligands to synthesize organic carboxylic acid esters and their derivatives that have one more carbon atom than the olefin. Currently, the reported catalyst systems for olefin hydrogenation are mainly Rh-P, Pd-P, or Co-N catalytic systems, and the catalytic reactions can be homogeneous or heterogeneous. Among these, the Pd-P catalytic system has become the most widely studied catalyst system in olefin hydrogenation due to its advantages such as mild reaction conditions, excellent catalytic performance, and good substrate universality.

[0004] In the Pd-P catalytic system for the hydrogen esterification of olefins, the research and development of ligands plays a crucial role, significantly influencing the activity and selectivity of the hydrogen esterification reaction. Currently, the most frequently reported phosphine ligands are monophosphine and diphosphine ligands, and more recently, triphosphine and tetraphosphine ligands have been developed. While these ligands exhibit high catalytic activity, they suffer from drawbacks such as extreme instability in air, complex synthesis methods, high cost, and poor catalytic activity. Therefore, there is an urgent need to develop ligands for the hydrogen esterification of olefins that offer good stability, simple synthesis methods, and excellent catalytic performance. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of complex ligand synthesis methods and poor catalytic activity in existing olefin hydrogen esterification catalysts.

[0006] To achieve the above objectives, a first aspect of the present invention provides a diphosphine ligand having the structure shown in formula (I):

[0007]

[0008] In equation (I),

[0009] R1 and R2 are each independently selected from one of methyl, ethyl, phenyl, tert-butyl, and diethylamino, and X is selected from one of -CH2- and -O-.

[0010] A second aspect of the present invention provides a method for preparing the diphosphine ligand described in the first aspect, the method comprising the following steps: in the presence of a protective atmosphere,

[0011] S1: In the presence of a solvent, the compound shown in formula (II) is brought into a first contact with an organolithium metal compound to obtain an intermediate product;

[0012] S2: The intermediate product is subjected to a second contact with compound PClR1R2 to obtain the diphosphine ligand shown in formula (I);

[0013]

[0014] In formula (II) and compound PClR1R2, the definitions of X, R1, and R2 are the same as those in the first aspect.

[0015] A third aspect of the present invention provides a catalyst composition for olefin hydrogen esterification reactions, the catalyst composition comprising a palladium compound, a diphosphine ligand, and an acidic substance;

[0016] The diphosphine ligand is the diphosphine ligand described in the first aspect.

[0017] A fourth aspect of the present invention provides a method for preparing an organic carboxylic acid ester, the method comprising:

[0018] In the presence of an organic solvent, an olefin, a fatty alcohol, carbon monoxide, and a catalyst are subjected to a hydrogen esterification reaction to generate an organic carboxylic acid ester.

[0019] The catalyst composition is the catalyst composition for olefin hydrogen esterification reaction described in the third aspect.

[0020] The diphosphine ligands provided by this invention exhibit high catalytic activity and good stability in catalyst compositions for hydrogen esterification reactions, thereby improving product yield. Furthermore, the preparation method of these diphosphine ligands is simple and has low production costs, demonstrating promising application prospects.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The diphosphine ligand provided by this invention has the advantages of simple and readily available raw materials and convenient synthesis method. Moreover, the diphosphine ligand has excellent catalytic activity in the hydrogen esterification of olefins to synthesize organic carboxylic acid esters, with high reaction conversion and selectivity, high product yield, and low production cost, and has high economic value and industrial application value. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] Unless otherwise stated, the terms used herein shall have the following meanings.

[0025] In this invention, "C" 2-18 "Alkenes" refers to alkenes with a total number of carbon atoms of 2-18, such as ethylene, propylene, 1-butene, isobutene, pentene, hexene, heptene, 1-octene, 2-octene, diisobutene, triisobutene, etc.

[0026] “C 1-4 "Aliphatic alcohols" refers to fatty alcohols with a total number of carbon atoms of 1-4, such as methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, etc.

[0027] As previously stated, a first aspect of the present invention provides a diphosphine ligand having the structure shown in formula (I):

[0028]

[0029] In equation (I),

[0030] R1 and R2 are each independently selected from one of methyl, ethyl, phenyl, tert-butyl, and diethylamino, and X is selected from one of -CH2- and -O-.

[0031] Preferably, in formula (I), R1 and R2 are tert-butyl groups, and X is selected from -CH2- and -O-. The inventors have found that under these preferred conditions, the obtained diphosphine ligand exhibits better catalytic activity in catalyst compositions used for hydrogen esterification reactions.

[0032] As previously described, a second aspect of the present invention provides a method for preparing the diphosphine ligand described in the first aspect, the method comprising: in the presence of a protective atmosphere,

[0033] S1: In the presence of a solvent, the compound shown in formula (II) is brought into a first contact with an organolithium metal compound to obtain an intermediate product;

[0034] S2: The intermediate product is subjected to a second contact with compound PClR1R2 to obtain the diphosphine ligand shown in formula (I);

[0035]

[0036] In formula (II) and compound PClR1R2, the definitions of X, R1, and R2 are the same as those in the first aspect.

[0037] Preferably, the conditions for the first contact include: a temperature of -78°C to 50°C and a reaction time of 20-120 min; the conditions for the second contact include: a temperature of -78°C to 100°C and a time of 1-6 h.

[0038] More preferably, the conditions for the first contact include: a temperature of -20°C to 50°C and a reaction time of 20-60 min; the conditions for the second contact include: a temperature of 0-50°C and a time of 1-3 h.

[0039] Preferably, the organometallic lithium compound is selected from at least one of methyl lithium, ethyl lithium, n-butyl lithium, tert-butyl lithium, diisopropylamino lithium, pentyl lithium, and phenyl lithium.

[0040] In a preferred embodiment, the molar ratio of the compound represented by formula (II) to the organolithium metal compound and the compound PClR1R2 is 1:1.5-3:1.5-3.

[0041] Preferably, the protective atmosphere is argon.

[0042] Preferably, the amount of solvent used is 1-10 L relative to 1 mol of the organolithium metal compound.

[0043] Preferably, the solvent is selected from at least one of chloroform, dichloromethane, 1,2-dichloroethane, diethyl ether, tetrahydrofuran, methyl tert-butyl ether, 2-methyltetrahydrofuran, cyclopentane, n-pentane, n-hexane, cyclohexane, and n-heptane.

[0044] In a preferred embodiment, the method further includes: quenching the material after the second contact with a saturated ammonium chloride aqueous solution, and then sequentially performing separation, water washing, rotary evaporation, and column chromatography to obtain the diphosphine ligand shown in formula (I).

[0045] The compounds represented by formula (II) in this invention can be synthesized or purchased using techniques known in the art; this invention does not impose any particular limitations on this.

[0046] As previously described, a third aspect of the present invention provides a catalyst composition for olefin hydrogen esterification reactions, the catalyst composition comprising a palladium compound, a diphosphine ligand, and an acidic substance;

[0047] The diphosphine ligand is the diphosphine ligand described in the first aspect.

[0048] Preferably, the palladium compound is selected from at least one of palladium acetate, palladium chloride, bis(triphenylphosphine)palladium dichloride, bis(acetonitrile)palladium dichloride, (1,5-cyclooctadiene)palladium dichloride, allyl palladium chloride, tetra(triphenylphosphine)palladium, palladium acetylacetonate, bis(dibenzylacetonate)palladium, and tri(dibenzylacetonate)palladium.

[0049] More preferably, the palladium compound is selected from at least one of palladium acetate, palladium chloride, allyl palladium chloride, and palladium acetylacetonate.

[0050] In a preferred embodiment, the molar ratio of the palladium compound to the diphosphine ligand, calculated as palladium element, is 1:0.1-200; more preferably, it is 1:1-100.

[0051] Preferably, the molar ratio of the palladium compound to the diphosphine ligand, calculated as palladium element, is 1:1-10. The inventors have found that, in this preferred embodiment, the reaction efficiency of the catalyst composition is more conducive to increasing the conversion rate of the reactants.

[0052] In a preferred embodiment, the acidic substance is selected from at least one of perchloric acid, sulfuric acid, phosphoric acid, hydrochloric acid, formic acid, acetic acid, oxalic acid, methanesulfonic acid, trifluoromethanesulfonic acid, tert-butanesulfonic acid, p-toluenesulfonic acid, 2-hydroxy-propane-2-sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, and dodecyl sulfonic acid.

[0053] Preferably, the molar ratio of the acidic substance to the palladium compound (calculated as palladium) is 0.1-100:1, more preferably 5-80:1.

[0054] The present invention does not impose any particular requirements on the preparation method of the catalyst composition for olefin hydrogen esterification reaction; those skilled in the art can use conventional methods in the field. Exemplarily, the various components of the catalyst composition are mixed.

[0055] Compared with existing hydrogen esterification catalysts, the catalyst composition for olefin hydrogen esterification provided by this invention not only improves reaction efficiency and reduces costs, but also increases product yield, thus having higher practical value.

[0056] As previously described, a fourth aspect of the present invention provides a method for preparing an organic carboxylic acid ester, the method comprising:

[0057] In the presence of an organic solvent, an olefin, a fatty alcohol, carbon monoxide, and a catalyst are subjected to a hydrogen esterification reaction to generate an organic carboxylic acid ester.

[0058] The catalyst composition is the catalyst composition for olefin hydrogen esterification reaction described in the third aspect.

[0059] In a preferred embodiment, the conditions for the hydrogen esterification reaction include: a reaction pressure of 1-20 MPa, a reaction temperature of 50-160°C, and a reaction time of 2-30 h.

[0060] More preferably, the conditions for the hydrogen esterification reaction include: a reaction pressure of 2-10 MPa, a reaction temperature of 70-130°C, and a reaction time of 4-20 h.

[0061] Preferably, the molar ratio of the catalyst composition to the olefin, calculated as palladium, is 0.00001-0.05:1.

[0062] More preferably, the molar ratio of the catalyst composition to the olefin, calculated as palladium, is 0.0002-0.02:1. The inventors have found that, under this preferred condition, the yield of the organic carboxylic acid ester is higher.

[0063] In a preferred embodiment, the olefin is C 2-18 Olefins; preferably C 2-12 The olefin is an olefin. More preferably, the olefin is isobutylene and / or diisobutylene.

[0064] Preferably, the fatty alcohol is C 1-4 More preferably, the fatty alcohol is methanol and / or ethanol.

[0065] In a preferred embodiment, the organic solvent is at least one selected from fatty alcohols, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, acetonitrile, ethyl acetate, butyl acetate, benzene, toluene, anisole, xylene, dichloromethane, chloroform, and chloroform.

[0066] In this invention, when a fatty alcohol is used as the organic solvent in the hydrogen esterification reaction, the fatty alcohol serves as both a reactant and a solvent. Preferably, the molar ratio of the olefin to the fatty alcohol is 1:3-50. When the organic solvent in the hydrogen esterification reaction is an organic solvent other than a fatty alcohol, the molar ratio of the olefin to the fatty alcohol is 1:1-10.

[0067] The present invention will now be described in detail through preparation examples and test examples. Unless otherwise specified, all raw materials used in the following preparation and test examples are commercially available.

[0068] In the following preparation examples and embodiments, room temperature refers to a temperature condition that does not require additional heating or cooling.

[0069] The analytical instruments and methods used in the examples are as follows:

[0070] 400MHz nuclear magnetic resonance spectrometer: Instrument manufacturer: BRUKER, model: Ascend 400;

[0071] Gas chromatography-mass spectrometry system: Agilent 5977B-7820A;

[0072] Gas chromatograph: Agilent 7820A;

[0073] Gas chromatography column: 0.2 mm (ID) × 50 m (L) capillary column; detector: FID; vaporization chamber temperature: 300 °C; column oven temperature: 60 °C; detector temperature: 300 °C; argon flow rate: 0.5 mL / min; hydrogen flow rate: 30 mL / min; air flow rate: 400 mL / min; injection volume: 0.2 μL. The conversion of olefins and the selectivity of the products were calculated using the area normalization method. Temperature program: Preheat to column temperature 60 °C, hold for 5 min, then increase from 60 °C to 260 °C at a rate of 10 °C / min, hold for 10 min.

[0074] Preparation Example 1: Preparation of Diphosphine Ligand A

[0075] Diphosphine ligand A was prepared according to the following synthetic route:

[0076]

[0077] (1) Preparation of 4,5-dibromo-9-fluorenone: 0.1 mol of 2,2',6,6'-tetrabromobiphenyl was added to a 1000 mL three-necked flask at room temperature. The flask was evacuated and filled with argon gas. This process was repeated three times. 300 mL of anhydrous tetrahydrofuran (THF) was added as a solvent in the argon atmosphere. The three-necked flask was then placed in a dry ice acetone bath, and 0.205 mol of a n-butyllithium solution in n-hexane (1.6 mol / L) was slowly added dropwise. After the addition was complete, the temperature was raised to 0 °C and the reaction was carried out for 0.5 h. The mixture was then cooled to -78°C using a dry ice acetone bath. 150 mL of 0.105 mol methyl chloroformate THF solution was added to the flask. After the addition was complete, the mixture was heated to room temperature and reacted for 2 hours. The reaction was then quenched by adding saturated ammonium chloride aqueous solution to the flask. The mixture was separated by liquid-liquid extraction and washed with water. The solvent was evaporated off using a rotary evaporator. The product 4,5-dibromo-9-fluorenone (30.2 g) was obtained by column chromatography.

[0078] (2) Preparation of 4,5-dibromo-9-fluorene: All 30.2 g of 4,5-dibromo-9-fluorene ketone was added to a 1000 mL three-necked flask, along with 300 mL of toluene as a solvent, 100 mL of an ethanol solution of 0.1 mol hydrazine hydrate, and 1.5 g of Raney nickel. After stirring evenly with electromagnetic stirring, the mixture was heated to reflux in an oil bath. The reaction was monitored for completion after two hours. The reaction solution was filtered to remove the catalyst, and the filtrate was evaporated to dryness on a rotary evaporator to obtain the product 4,5-dibromo-9-fluorene (28.6 g).

[0079] (3) Preparation of diphosphine ligand A: 28.6 g of 4,5-dibromo-9-fluorene was added to a 1000 mL three-necked flask at room temperature. The flask was evacuated and filled with argon gas. This process was repeated three times. 300 mL of dry THF was added as a solvent in the argon atmosphere. The three-necked flask was then placed in a dry ice acetone bath. 0.18 mol of n-butyllithium in n-hexane solution (1.6 mol / L) was slowly added dropwise. After the addition was complete, the temperature was raised to 0 °C and reacted for 0.5 h. The temperature was then lowered to -78 °C using a dry ice acetone bath. 0.18 mol of di-tert-butylphosphine chloride was added to the flask. After the addition was complete, the temperature was naturally raised to room temperature and reacted for 2 h. The reaction was quenched by adding a saturated ammonium chloride aqueous solution to the flask. After separation, the product diphosphine ligand A (36 g) was obtained by column chromatography.

[0080] The diphosphine ligand A prepared in the above preparation example was characterized by NMR, and the results are as follows: 1 H NMR (400MHz, CDCl3): δ = 4.12 (s, 2H), 7.33 (d, 2H), 7.16 (d, 2H), 7.06 (t, 2H), 1.06 (s, 36H); 13 C NMR (400MHz, CDCl3): δ=138.1, 142.5, 37.1, 137.9, 124.0, 130.6, 127.5, 31.0, 27.9.

[0081] Preparation Example 2: Preparation of Diphosphine Ligand B

[0082] Diphosphine ligand B was prepared according to the following synthetic route:

[0083]

[0084] At room temperature, 0.1 mol of 1,9-dibromodibenzofuran was added to a 1000 mL three-necked flask, and the flask was evacuated and filled with argon gas. This process was repeated three times. 300 mL of dry THF was added as a solvent in an argon atmosphere. The flask was then placed in a dry ice acetone bath, and 0.20 mol of a hexane solution of n-butyllithium (1.6 mol / L) was slowly added dropwise. After the addition was complete, the temperature was raised to 0 °C and reacted for 0.5 h. The temperature was then lowered to -78 °C using a dry ice acetone bath. 0.20 mol of di-tert-butylphosphine chloride was added to the flask. After the addition was complete, the temperature was naturally raised to room temperature and reacted for 2 h. The reaction was quenched by adding a saturated ammonium chloride aqueous solution. After separation, the product was washed with water, and the solvent was evaporated on a rotary evaporator. The product, diphosphine ligand B (36.8 g), was obtained by column chromatography.

[0085] The diphosphine ligand B prepared in the above preparation example was characterized by NMR, and the results are as follows: 1H NMR (400MHz, CDCl3): δ=7.59 (d, 2H), 7.38 (t, 2H), 7.36 (d, 2H), 1.06 (s, 36H); 13 C NMR (400MHz, CDCl3): δ=150.9, 110.5, 124.1, 124.8, 131.6, 118.2, 31.0, 27.9.

[0086] Example 1

[0087] In a 200 mL high-pressure reactor, catalyst composition M1 (containing 0.03 mmol palladium acetylacetone, 0.12 mmol diphosphine ligand A, and 0.24 mmol p-toluenesulfonic acid), anhydrous methanol (900 mmol), and isobutylene (30 mmol) were added sequentially. After sealing the reactor, it was purged three times with carbon monoxide, and then carbon monoxide was added again until the reactor pressure reached 4.0 MPa. The reaction temperature was controlled by a temperature controller and raised to 100 °C for 12 hours to obtain methyl isovalerate. After cooling to room temperature, the gas was slowly released, and the reactor was unloaded. The obtained methyl isovalerate product was qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS) and quantitatively analyzed by gas chromatography. The specific results are shown in Table 1.

[0088] Example 2

[0089] The hydrogen esterification reaction was carried out using a method similar to that in Example 1, except that the catalyst composition M2 contained 0.03 mmol of palladium acetylacetone, 0.12 mmol of diphosphine ligand B, and 0.36 mmol of p-toluenesulfonic acid.

[0090] The remaining steps are the same as in Example 1, and the specific results of the product analysis are shown in Table 1.

[0091] Example 3

[0092] The hydrogen esterification reaction was carried out using a method similar to that in Example 1, except that the catalyst composition M3 contained 0.03 mmol palladium acetate, 0.12 mmol diphosphine ligand B, and 0.30 mmol p-toluenesulfonic acid; the amount of anhydrous methanol was 1200 mmol; and the reaction temperature was controlled to rise to 90°C using a temperature controller.

[0093] The remaining steps are the same as in Example 1, and the specific results of the product analysis are shown in Table 1.

[0094] Example 4

[0095] The hydrogen esterification reaction was carried out using a method similar to that in Example 1, except that the catalyst composition M4 contained 0.03 mmol palladium acetate, 0.12 mmol diphosphine ligand A, and 0.60 mmol p-toluenesulfonic acid; the amount of anhydrous methanol was 1200 mmol; and the reaction temperature was controlled to rise to 90°C using a temperature controller.

[0096] The remaining steps are the same as in Example 1, and the specific results of the product analysis are shown in Table 1.

[0097] Example 5

[0098] In a 200 mL high-pressure reactor, catalyst composition M5 (containing 0.06 mmol palladium acetylacetone, 0.24 mmol diphosphine ligand A, and 0.60 mmol p-toluenesulfonic acid), anhydrous methanol (900 mmol), and diisobutylene (30 mmol) were added sequentially. After sealing the reactor, it was purged three times with carbon monoxide, and then carbon monoxide was added again until the reactor pressure reached 4.0 MPa. The reaction temperature was controlled by a temperature controller and raised to 100 °C for 12 hours for hydrogen esterification. After cooling to room temperature, the gas was slowly released, the reactor was removed, and the obtained methyl isononanoate was qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS) and quantitatively analyzed by gas chromatography. The specific results are shown in Table 1.

[0099] Example 6

[0100] The hydrogen esterification reaction was carried out using a method similar to that in Example 5, except that: the amount of anhydrous methanol was 1200 mmol, the amount of diisobutylene was 30 mmol, carbon monoxide was introduced to the pressure of the reactor to 6.0 MPa, the reaction temperature was controlled by a temperature controller to rise to 120°C, and the hydrogen esterification reaction was carried out for 20 hours.

[0101] The remaining steps are the same as in Example 5, and the specific results of the product analysis are shown in Table 1.

[0102] Comparative Example 1

[0103] The hydrogen esterification reaction was carried out using the method of Example 1, except that the composition of the catalyst composition was different. In this comparative example, the catalyst composition DM1 contained 0.03 mmol of palladium acetylacetonate, 0.12 mmol of 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, and 0.24 mmol of p-toluenesulfonic acid.

[0104] The remaining steps are the same as in Example 1, and the specific results of the product analysis are shown in Table 1.

[0105] Comparative Example 2

[0106] The hydrogen esterification reaction was carried out using the method of Example 3, except that the composition of the catalyst composition was different. In this comparative example, the catalyst composition DM2 contained 0.03 mmol of palladium acetate, 0.12 mmol of 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene, and 0.30 mmol of p-toluenesulfonic acid.

[0107] The remaining steps are the same as in Example 3, and the specific results of the product analysis are shown in Table 1.

[0108] Table 1

[0109]

[0110]

[0111] The results above show that, compared with catalyst composition DM1 and catalyst composition DM2, the catalyst formed by the diphosphine ligand and the palladium compound provided by the present invention has higher conversion rate and selectivity, higher product yield, and lower production cost in the hydrogen esterification reaction, and has higher economic value and industrial application value.

[0112] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A diphosphine ligand characterized in that, The ligand has a structure shown in formula (I): Formula (I); In formula (I), X is selected from -CH2- and -O-; R1 and R2 are tert-butyl.

2. A process for the preparation of the diphosphine ligand of claim 1, characterized in that, The method comprises the following steps: S1: in the presence of a solvent, a compound shown in formula (II) is contacted with a metal organic lithium compound to obtain an intermediate product; S2: the intermediate product is contacted with a compound PClR1R2 to obtain a diphosphine ligand shown in formula (I); Formula (II); In formula (II) and the compound PClR1R2, the definitions of X, R1 and R2 correspond to the definitions of X, R1 and R2 in claim 1.

3. The method of claim 2, wherein, The first contact condition includes a temperature of -78℃ to 50℃ and a reaction time of 20-120 min; the second contact condition includes a temperature of -78℃ to 100℃ and a time of 1-6 h; and the metal organic lithium compound is selected from at least one of methyl lithium, ethyl lithium, n-butyl lithium, tert-butyl lithium, diisopropyl amine lithium, amyl lithium and phenyl lithium.

4. A catalyst composition for olefin hydroesterification reaction, characterized by, The catalyst composition contains a metal palladium compound, a diphosphine ligand and an acidic substance; The diphosphine ligand is the diphosphine ligand of claim 1.

5. The catalyst composition of claim 4, wherein the catalyst composition comprises: The metal palladium compound is selected from at least one of palladium acetate, palladium chloride, bis(triphenylphosphine)palladium dichloride, bis(acetonitrile)palladium dichloride, (1,5 cyclooctadiene)palladium dichloride, allylpalladium chloride, tetrakis(triphenylphosphine)palladium, palladium acetylacetonate, bis(benzonitrile)palladium, tris(benzonitrile)dipalladium.

6. The catalyst composition of claim 5, wherein, The metal palladium compound is selected from at least one of palladium acetate, palladium chloride, allyl palladium chloride and palladium acetylacetone.

7. The catalyst composition of claim 4, wherein the catalyst composition comprises: The molar ratio of the metal palladium compound to the diphosphine ligand, in terms of palladium element, is 1:0.1-200.

8. The catalyst composition of claim 7, wherein, The molar ratio of the metal palladium compound to the diphosphine ligand, in terms of palladium element, is 1:1-10.

9. The catalyst composition of claim 4 or 5, wherein, The acidic substance is selected from at least one of perchloric acid, sulfuric acid, phosphoric acid, hydrochloric acid, formic acid, acetic acid, oxalic acid, methyl sulfonic acid, trifluoromethanesulfonic acid, tert-butyl sulfonic acid, p-toluene sulfonic acid, 2-hydroxy-propane-2-sulfonic acid, 2,4,6-trimethyl benzene sulfonic acid and dodecyl sulfonic acid.

10. The catalyst composition of claim 4 or 5, wherein The molar ratio of the acidic substance to the metal palladium compound, in terms of palladium element, is 0.1-100:

1.

11. The catalyst composition of claim 4 or 5, wherein The molar ratio of the acidic substance to the metal palladium compound, in terms of palladium element, is 5-80:

1.

12. A method for the preparation of an organic carboxylic acid ester, characterized in that, The method comprises: In the presence of an organic solvent, an olefin, a fatty alcohol, carbon monoxide and a catalyst composition are subjected to a hydroesterification reaction to generate an organic carboxylic acid ester; The catalyst composition is the catalyst composition for olefin hydroesterification reaction according to any one of claims 4-11.

13. The method of claim 12, wherein, The hydroesterification reaction condition includes a reaction pressure of 1-20 MPa, a reaction temperature of 50-160℃ and a reaction time of 2-30 h.

14. The method of claim 13, wherein, The hydroesterification reaction condition includes a reaction pressure of 2-10 MPa, a reaction temperature of 70-130℃ and a reaction time of 4-20 h.

15. The method of claim 12 or 13, wherein, The molar ratio of the catalyst composition to the olefin, in terms of palladium element, is 0.00001-0.05:

1.

16. The method of any of claims 12-14, wherein, The olefin is a C 2-18 olefin; The organic solvent is at least one of a fatty alcohol, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, acetonitrile, ethyl acetate, butyl acetate, benzene, toluene, anisole, xylene, dichloromethane, trichloromethane and chloroform; The fatty alcohol is a C 1-4 fatty alcohol; The molar ratio of the olefin to the fatty alcohol is 1:3-50.

17. The method of claim 16, wherein, The fatty alcohol is methanol and / or ethanol.

18. The method of claim 16, wherein, The olefin is a C 2-12 olefin.

19. The method of claim 18, wherein, The olefin is isobutene and / or diisobutene. The olefin is isobutene and / or diisobutene.

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