Ethylene carbonylation catalyst and its application

Abstract

The present invention relates to an ethylene carbonylation catalyst, comprising an active component, a bidentate phosphine ligand based on a xanthene or a xanthene-like skeleton, and an acidic additive. Compared with the prior art, the present invention uses a bidentate phosphine ligand catalyst system containing a xanthene or a xanthene-like skeleton, and the bidentate phosphine ligand of the xanthene or a xanthene-like skeleton has both a rigid skeleton structure of a rigid ligand and flexible chemical modifiability, which is conducive to forming a spatially favorable coordination mode and a structurally stable active catalyst system, and the catalyst has high activity, good stability, and stable life.

Description

Technical Field

[0001] The invention belongs to the chemical field of homogeneous catalysis and fine chemical synthesis, relates to a method for preparing methyl propionate by taking ethylene as a raw material, and in particular to an ethylene carbonylation catalyst and application thereof. Background Art

[0002] Methyl propionate is widely used in the industries of pesticide, food processing, cosmetics, etc. as a solvent, food additive or fragrance. It is also a very important organic synthesis intermediate and chemical raw material. At present, the synthesis method of methyl propionate mainly includes the esterification reaction of propionic acid and methanol and the carbonylation esterification reaction of ethylene, carbon monoxide and methanol. For example, in patent CN102320962A, pyridine and imidazole ionic liquids or p-toluenesulfonic acid are selected as catalysts to realize the preparation of methyl propionate by esterification reaction of propionic acid and methanol as raw materials; in addition, patent CN102531890A discloses a catalytic system composed of palladium complex / phosphine ligand / acidic ionic liquid, and the preparation of methyl propionate by carbonylation esterification reaction of ethylene under this catalyst system; patent CN103319337A discloses a composite catalyst system with palladium acetate as the main catalyst-metal ions such as cobalt, nickel or ruthenium as cocatalysts, and the reaction of preparing methyl propionate by carbonylation esterification reaction with ethylene as the raw material.

[0003] In the 1930s, the carbonyl synthesis of methyl propionate attracted the attention of the academic community. Among them, German scientist Reppe proposed a synthesis process for the direct synthesis of methyl propionate by ethylene carbonyl esterification. At present, the reported catalyst system is mainly composed of a metal palladium compound and a phosphine ligand, wherein the phosphine ligand of different structure and composition plays a decisive role in the activity, selectivity and stability of the palladium catalyst. At present, in the open patents, such as US2005085671A1, US2001051745A1, US6476255B1, EP-A-0499329, EP-A-0495547, EP-A-04489472, a variety of catalyst systems constructed by alkyl phosphine ligands, cycloalkyl phosphine ligands or bidentate phosphine ligands with unique structures and compositions have been reported. Among them, Lucite of the UK has disclosed a group of bidentate phosphine ligands with substituted aromatic bridges, such as 1,2-bis(di-tert-butylphosphinomethyl)benzene ligand (DTBPMB) (Chem. Commun. 1999, 1877-1878; WO 96 / 19434; WO2004 / 014552 AD); Evonik Degussa of Germany has disclosed a 1,1'-bis(tert-butylphenylphosphino)ferrocene ligand (Angew. Chem. Int. Ed., 2017, 56(19), 5267-5271; US ​​2017 / 0022234 A1). Under the action of the catalyst composed of the phosphine ligand and the transition metal compound, the carbonylation esterification reaction of ethylene, CO and methanol as raw materials proceeds smoothly, and the target product of methyl propionate with good yield is obtained. Although the phosphine ligands disclosed in the above patents show good performance in the ethylene carbonylation esterification reaction, the phosphine ligands used are expensive, difficult to prepare, unstable in the air, etc., which leads to high investment costs and complicated production processes in the process of industrial application. Therefore, it is still very important to develop a new type of phosphine ligand-modified palladium catalytic system that is cheap, stable, simple to synthesize, and has excellent catalytic performance. Summary of the invention

[0004] The purpose of the present invention is to provide an ethylene carbonylation catalyst and its preparation method and application in order to solve the above problems.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] An ethylene carbonylation catalyst comprises an active component, a bidentate phosphine ligand based on a xanthene or a xanthene-like skeleton, and an acidic additive.

[0007] Furthermore, the molar ratio of the bidentate phosphine ligand of the xanthene or xanthene-like skeleton, the acidic additive and the active component is (0.1-100):(0.1-1000):1.

[0008] Furthermore, the molar ratio of the bidentate phosphine ligand of the xanthene or xanthene-like skeleton, the acidic additive and the active component is preferably (0.5-50):(1-100):1; further, the molar ratio of the bidentate phosphine ligand of the xanthene or xanthene-like skeleton, the acidic additive and the active component is preferably (1-10):(1-10):1.

[0009] Furthermore, the structural formula of the bidentate phosphine ligand of the xanthene or xanthene-like skeleton is one of the following structural formulas:

[0010]

[0011] In formula (1), (2) and (3):

[0012] R is a substituted or unsubstituted group, including H, halogen, sulfonic acid, carboxyl, amine, hydroxyl, trifluoromethyl, nitro, alkyl, alkoxy, aryl, phenoxy, and heterocycle;

[0013] R1 and R2 are unsubstituted aryl or substituted aryl, C1-C5 alkyl, C1-C5 alkoxy, C3-C 15 cycloalkyl, unsubstituted or substituted C7-C 15 Arylalkyl;

[0014] R' is an unsubstituted aryl or substituted aryl, a C1-C5 alkyl, a C3-C 15 cycloalkyl, unsubstituted or substituted C7-C 15 of arylalkyl.

[0015] Furthermore, the structural formula of the bidentate phosphine ligand of the xanthene or xanthene-like skeleton is one of the following structural formulas:

[0016]

[0017] Furthermore, the active component is selected from at least one of palladium compounds, cobalt compounds, nickel compounds and ruthenium compounds.

[0018] Furthermore, the palladium compound is selected from one or more of palladium dichloride, bis(acetonitrile)palladium dichloride, palladium acetate, bis(triphenylphosphine)palladium dichloride, (1,5-cyclooctadiene)palladium dichloride, allylpalladium chloride, tetrakistriphenylphosphine palladium, palladium acetylacetonate, bis(dibenzylideneacetone)palladium and tris(dibenzylideneacetone)dipalladium.

[0019] Further, the acidic additive is selected from low-carbon carboxylic acids, inorganic acids, sulfonic acids, halogenated carboxylic acids, and halogenated sulfonic acids;

[0020] The low-carbon carboxylic acid includes one or more of formic acid, acetic acid, propionic acid, and oxalic acid;

[0021] The halogenated carboxylic acid includes one or more of trichloroacetic acid and trifluoroacetic acid;

[0022] The inorganic acid includes one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid;

[0023] The sulfonic acid includes one or more of p-toluenesulfonic acid, dodecylsulfonic acid, trifluoromethanesulfonic acid, and aluminum trifluoromethanesulfonate.

[0024] Furthermore, the catalyst may also be added with an auxiliary phosphine ligand, and the molar ratio of the auxiliary phosphine ligand to the palladium compound is (0.1-100):1.

[0025] Further, the auxiliary phosphine ligand is selected from bidentate phosphine ligands of xanthene or xanthene-like skeletons or commercially available phosphine ligands, including triphenylphosphine, triphenylphosphine oxide, 1,2-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf), 1,2-bis(di-tert-butylphosphinomethyl)benzene and 1,1'-bis(di-tert-butylphosphinomethyl)ferrocene. One or more.

[0026] The catalyst is used for carbonylation esterification reaction to generate methyl propionate with ethylene, carbon monoxide and methanol as raw materials, and the molar ratio of ethylene to palladium compound is 200-100000:1, preferably 500-10000:1, and more preferably 1000-5000:1.

[0027] During the carbonylation reaction, methanol and the catalyst are added to a high-pressure reactor, which is sealed and filled with ethylene and CO gas, with the pressure maintained at 1.0-5.0 MPa. After ensuring the airtightness of the reactor, the reaction is carried out at 80-200° C. for 1 to 48 hours.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention uses a bidentate phosphine ligand catalyst system containing a xanthene or xanthene-like skeleton. The bidentate phosphine ligand of the xanthene or xanthene-like skeleton has both the rigid skeleton structure of a rigid ligand and the flexible chemical modifiability, which is beneficial to the spatial coordination of the active elements in the catalyst and can improve the structural stability of the catalyst.

[0030] 2. The catalyst of the present invention uses a bidentate phosphine ligand of a xanthene or xanthene-like skeleton and an auxiliary phosphine ligand. The synergistic effect of the two ligands further improves the stability of the catalyst and prolongs the life of the catalyst.

[0031] 3. The present invention is a one-pot homogeneous synthesis method with mild reaction conditions and simple process. DETAILED DESCRIPTION

[0032] The present invention is described in detail below with reference to specific embodiments, but this is by no means a limitation of the present invention.

[0033] Examples 1-15

[0034] Catalytic Reaction of Ethylene to Methyl Propionate over Different Pd Compounds and Bidentate Phosphine Ligands

[0035] Specific experimental steps: 0.01mmol of Pd compound, 0.012mmol of bidentate phosphine ligand, 0.05mmol of p-toluenesulfonic acid, 40mL of methanol and 40mL of toluene were added to a 200mL reactor lined with polytetrafluoroethylene in sequence, and the air tightness of the device was checked after sealing, and the air in the reactor was replaced with CO. Then, a mixed gas of CO / ethylene (volume ratio of 3 / 1) was introduced and pressurized to 3.0MPa, and the reaction was carried out in a constant temperature heating mantle for 4h, and the pressure was slowly released after cooling to room temperature, and the conversion rate of methanol and the selectivity and yield of the product were calculated by weighing method or GC-MS.

[0036] The bidentate phosphine ligand used in the embodiment is selected from the compounds of the following chemical formula:

[0037]

[0038] Table 1 Catalytic reaction results of Example 1-15 catalysts for ethylene carbonylation esterification reaction

[0039]

[0040]

[0041] Examples 16-25

[0042] Effect of different acidic additives on the catalytic reaction of ethylene to methyl propionate

[0043] Specific experimental steps: 0.01mmol of Pd compound, 0.012mmol of bidentate phosphine ligand L1, 0.05mmol of acidic additive, 40mL of methanol and 40mL of toluene were added to 200mL of polytetrafluoroethylene liner in sequence. The liner was placed in a high-pressure reactor, and the air tightness of the device was checked after sealing, and the air in the reactor was replaced with CO. Then CO / ethylene (volume ratio of 3 / 1) was introduced to 3.0MPa, and the reaction was carried out in a constant temperature heating mantle for 4h, and the pressure was slowly released after cooling to room temperature. The conversion rate of methanol and the selectivity and yield of the product were calculated by weighing or GC-MS.

[0044] Table 2 Catalytic reaction results of Example 16-25 catalysts for ethylene carbonylation esterification reaction

[0045]

[0046] Examples 26-35

[0047] Catalytic reaction of ethylene to methyl propionate by adding other auxiliary phosphine ligands

[0048] Specific experimental steps: 0.01mmol of Pd2(dba)3 or Pd(OAc)2, 0.012mmol of bidentate phosphine ligand L1 or L6, 0.01mmol of auxiliary phosphine ligand 0.01, 0.05mmol of p-toluenesulfonic acid, 40mL of methanol and 40mL of toluene were added to 500mL of polytetrafluoroethylene liner in sequence. The liner was placed in a high-pressure reactor, and the air tightness of the device was tested after sealing. The air in the reactor was replaced with CO. Then CO / ethylene (volume ratio 3 / 1) was introduced, and the mixed gas was mixed to 3.0MPa, and the reaction was carried out in a constant temperature heating mantle for 4h. After cooling to room temperature, the pressure was slowly released. The conversion rate of methanol and the selectivity and yield of the product were calculated by weighing or GC-MS.

[0049] The auxiliary phosphine ligand used in the embodiment is selected from the compounds of the following chemical formula:

[0050] A1 is triphenylphosphine (PPh3);

[0051] A2 is 1,2-bis(diphenylphosphino)ethane (CAS: 1663-45-2, dppe);

[0052] A3 is 1,2-bis(diphenylphosphino)propane (CAS: 6737-42-4, dppp);

[0053] A4 is 1,2-bis(diphenylphosphino)butane (CAS: 7688-25-7, dppb);

[0054] A5 is 1,1-bis(diphenylphosphino)ferrocene (CAS: 12150-46-8, dppf);

[0055] A6 is 1,2-bis(di-tert-butylphosphinomethyl)benzene (CAS: 121954-50-5);

[0056] A7 is 2,2'-bis-(diphenylphosphino)-1,1'-binaphthyl (CAS: 76189-56-5);

[0057] A8 is 2-diphenylphosphinobenzoic acid CAS: 17261-28-8;

[0058] A9 is 2-diphenylphosphinobenzenesulfonic acid (CAS: 111864-25-6);

[0059] A10 is triphenyl phosphite (CAS: 101-02-0).

[0060] Table 3 Catalytic reaction results of Example 26-35 catalysts for ethylene carbonylation esterification reaction

[0061]

[0062]

[0063] Examples 36-45

[0064] Catalytic reaction of ethylene to methyl propionate with different raw material ratios

[0065] Specific experimental steps: Pd(OAc)2, bidentate phosphine ligand L1, p-toluenesulfonic acid, appropriate amount of methanol and toluene are added to the polytetrafluoroethylene liner in sequence. The specific ratio is shown in Table 4. The liner is placed in a high-pressure reactor, the air tightness of the device is tested after sealing, and the air in the reactor is replaced with CO. Then CO / ethylene (volume ratio 3 / 1) is introduced to 3.0MPa, and the reaction is carried out in a constant temperature heating mantle for 4h. After cooling to room temperature, the pressure is slowly released. The conversion rate of methanol and the selectivity and yield of the product are calculated by weighing or GC-MS.

[0066] Table 4 Catalytic reaction results of Example 36-45 catalysts on ethylene carbonylation esterification reaction

[0067]

[0068] Comparative Examples 1-6

[0069] In Comparative Examples 1-6, the bidentate phosphine ligand L1 in Examples 1-6 was replaced by the ligands in Table 5, respectively, and the rest were the same.

[0070] Table 5 Comparative Example 1-6 Catalysts for Ethylene Carbonylation Esterification Catalytic Reaction Results

[0071]

[0072]

[0073] The service life of the catalyst is tested as follows.

[0074] The catalysts of Examples 1-15, 26-35 and the comparative example were recycled in the reaction of preparing methyl propionate by ethylene carbonylation esterification to evaluate the activity and stability. The catalysts of the above examples were continuously reacted in a continuous reactor for preparing methyl propionate by ethylene carbonylation esterification, and the palladium loss was detected by ICP-OES. The turnover number (TON) of the catalyst was tested. The specific results are shown in Table 6.

[0075] Table 6 Catalyst service life test results

[0076]

[0077]

[0078] As can be seen from Table 6, the catalyst of the present invention can be recycled for at least 40 times while still maintaining good activity and stability. The catalyst can be used in a continuous reactor for preparing methyl propionate by ethylene carbonylation esterification for at least 150 hours. There is no obvious palladium loss as detected by ICP-OES, and the TON is at least 60,000 mol methyl propionate / mol palladium. For Comparative Examples 1-6, when a phosphine ligand not based on xanthene or xanthene-like skeleton is used, the catalyst can be recycled for up to 30 times. The catalyst can be used in a continuous reactor for preparing methyl propionate by ethylene carbonylation esterification for up to 100 hours. There is no obvious palladium loss as detected by ICP-OES, and the TON is up to 40,000 mol methyl propionate / mol palladium.

[0079] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An ethylene carbonylation catalyst, characterized in that The invention comprises an active component, a bidentate phosphine ligand based on a xanthene or a xanthene-like skeleton, and an acidic additive; The active component is selected from at least one of palladium compounds, cobalt compounds, nickel compounds and ruthenium compounds; The structural formula of the bidentate phosphine ligand of the xanthene or xanthene-like skeleton is one of the following structural formulas: ； The molar ratio of the bidentate phosphine ligand of the xanthene or xanthene-like skeleton, the acidic additive and the active component is (0.1-100): (0.1-1000): 1; The acidic additive is selected from low-carbon carboxylic acids, inorganic acids, sulfonic acids, halogenated carboxylic acids, and halogenated sulfonic acids; the low-carbon carboxylic acids include one or more of formic acid, acetic acid, propionic acid, and oxalic acid; The halogenated carboxylic acid includes one or more of trichloroacetic acid and trifluoroacetic acid; The inorganic acid includes one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; The sulfonic acid includes one or more of p-toluenesulfonic acid, dodecylsulfonic acid, and trifluoromethanesulfonic acid.

2. An ethylene carbonylation catalyst according to claim 1, characterized in that: The palladium compound is selected from one or more of palladium dichloride, bis(acetonitrile)palladium dichloride, palladium acetate, bis(triphenylphosphine)palladium dichloride, (1,5-cyclooctadiene)palladium dichloride, allylpalladium chloride, tetrakistriphenylphosphine palladium, palladium acetylacetonate, bis(dibenzylideneacetone)palladium and tris(dibenzylideneacetone)dipalladium.

3. An ethylene carbonylation catalyst according to claim 1, characterized in that: The catalyst is further added with an auxiliary phosphine ligand, and the molar ratio of the auxiliary phosphine ligand to the active component is 0.1-100:

1.

4. An ethylene carbonylation catalyst according to claim 3, characterized in that: The auxiliary phosphine ligand is selected from one or more of triphenylphosphine, triphenylphosphine oxide, 1,2-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,2-bis(diphenylphosphino)propane, 1,2-bis(diphenylphosphino)butane, 1,1'-bis(diphenylphosphino)ferrocene, 1,2-bis(di-tert-butylphosphinomethyl)benzene and 1,1'-bis(di-tert-butylphosphinomethyl)ferrocene.

5. The use of an ethylene carbonylation catalyst as claimed in claim 1, characterized in that: The catalyst is used for carrying out carbonylation esterification reaction with ethylene, carbon monoxide and methanol as raw materials to generate methyl propionate.

6. The use of an ethylene carbonylation catalyst according to claim 5, characterized in that: The molar ratio of ethylene to the palladium compound is 200-100000:1; During the carbonylation reaction, methanol and the catalyst are added to the reactor, and ethylene and carbon monoxide gas are charged. The reaction pressure is 1.0-5.0 MPa and the reaction temperature is 80-200°C.

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