Low-cost synthesis method of furan acetate compound

Abstract

The invention discloses a low-cost synthesis method of a furan acetate compound, which is characterized in that a derivative of bio-based furfuryl alcohol, namely a furfuryl ester compound, is used as a raw material, carbon monoxide gas is selected as a carbonyl source, and carbonylation reaction is carried out under the combined action of an organic solvent and a catalyst. The catalyst is composed of an eighth group metal salt and a phosphine ligand, and finally the furan acetate compound is generated. Compared with a publicly reported route for synthesizing the furan acetate compound through carbonylation by taking furfuryl alcohol as a raw material, the preparation route disclosed by the invention has remarkable advantages, additives such as alkali and dimethyl carbonate do not need to be used, and the production cost is effectively reduced on the premise of ensuring high yield of furan acetate.

Description

Technical Field

[0001] The present invention relates to a low-cost synthesis method of furan acetate compounds, and to a method for synthesizing furan acetate compounds by carbonylation to increase the carbon chain of furan ester compounds using furan ester compounds as raw materials, belonging to the fields of chemical synthesis and value-added conversion of biomass resources. Background Art

[0002] Furan acetate is a biomass-derived fine chemical and intermediate, and its structural formula is as follows: Among them, the substituent R is selected from alkyl groups.

[0003] Furan acetate compounds can be used as organic synthesis intermediates and are widely used in fields such as plastics, coatings, medicine, spices, and food. For example, the hydrogenolysis ring-opening of furan acetate can be used to prepare bio-based biodegradable plastic monomers 6-hydroxyhexanoate and ε-caprolactone (CN112898264B, Chem 2022, 8 , 1034 - 1049). At present, the main method for preparing furan acetate compounds is to react furan or furfuryl alcohol with cyanide and then hydrolyze to obtain the acid, and then further esterify. This route uses highly toxic cyanide and causes serious environmental pollution. Chinese patent CN112898247B discloses a route for synthesizing furan acetate compounds using bio-based furfuryl alcohol and carbon monoxide as raw materials and a combination of palladium metal salts, phosphine ligands, dimethyl carbonate, and base as catalysts. This route requires the addition of a large amount of dimethyl carbonate and base to the reaction system, which not only brings inconvenience to the separation of products and solvents, but also dimethyl carbonate decomposes and consumes during the reaction process, and a large amount needs to be replenished during the catalyst recycling process, increasing the production cost of the product. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-cost synthesis method of furan acetate compounds. The reaction route of the present invention does not require the use of additives such as bases and dimethyl carbonate, providing an important technical solution and experimental basis for the high-value utilization of bio-based furfuryl alcohol and its derivatives.

[0005] A low-cost synthesis method of furan acetate compounds is to add the raw material furan ester compound and the catalyst Group VIII metal salt and phosphine ligand to an organic solvent, introduce carbon monoxide gas, and carry out a carbonylation reaction at a temperature of 30 - 200 °C and a pressure of 0.1 - 6 MPa for 0.5 - 20 hours. The reaction product is the furan acetate compound; The structural formula of the raw material furan ester compound is: Among them, the substituent R is an alkyl group.

[0006] The amount of the Group VIII metal salt used is 0.01-10% of the molar amount of the furfuryl ester compound; the molar ratio of the Group VIII metal salt to the phosphine ligand is 1:1-1:10.

[0007] The Group VIII metal salt is selected from at least one of acetate, nitrate, chloride, bromide and acetylacetonate of palladium, platinum, rhodium and ruthenium.

[0008] The phosphine ligand is selected from at least one of triphenylphosphine, 1,1'-bis(diphenylphosphino)ferrocene, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,5-bis(diphenylphosphino)pentane, 1,6-bis(diphenylphosphino)hexane, tri-tert-butylphosphine, tricyclohexylphosphine, 1,2-bis(diphenylphosphino)benzene, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, bis(2-diphenylphosphinophenyl)ether, tri-p-phenylmethylphosphine, tri(4-fluorophenyl)phosphine, tri(pentafluorophenyl)phosphine, tri(4-chlorophenyl)phosphine, and tri(2-furan)phosphine.

[0009] The organic solvent is at least one of tetrahydrofuran, dichloroethane, methanol, ethanol, propanol, butanol, toluene and cyclohexane.

[0010] The present invention uses furfuryl ester raw materials as substrates, does not require in-situ esterification of furfuryl alcohol, does not require the addition of dimethyl carbonate, and does not require the addition of an alkali catalyst (the alkali is a catalyst for catalyzing the esterification of furfuryl alcohol and dimethyl carbonate).

[0011] The present invention has the following advantages over the prior art: No additives such as alkali and dimethyl carbonate are required in the synthesis, which effectively reduces the production cost while ensuring a high yield of furanacetate. The reaction system is simple, which facilitates the recycling of the catalyst system and significantly reduces the catalyst cost of the product. The high-yield synthesis of furanacetate can be achieved under mild reaction conditions, which is convenient for industrial production. DETAILED DESCRIPTION

[0012] The present invention is further described in detail below through specific examples, but the protection scope of the present invention is not limited to these examples. The experimental methods used in the examples are conventional methods unless otherwise specified; the materials, reagents, etc. used in the examples, unless otherwise specified, can be obtained from commercial channels.

[0013] Example 1 Weigh 20 mmol of furfuryl formate, 0.2 mmol of palladium acetate, 0.4 mmol of 1,3-bis(diphenylphosphino)propane, and 20 mL of methanol respectively, add them to a 100 mL reaction kettle, displace with CO six times, fill with 2 MPa of CO, stir and react at 100 °C for 4 hours, cool, add 10 mmol of internal standard (1,4-dioxane), and analyze by gas chromatography. The yield of methyl furanoacetate is 91%.

[0014] Structural formula of the product: Characterization data of the product methyl furanoacetate: 1 H NMR(400 MHz, CDCl 3 ) δ 7.40 (dd, J J =1.9,0.9 Hz, 1H), 6.38 (dd, J J =3.3, 1.9 Hz, 1H), 6.32 - 6.21 (m, 1H), 3.77 (s, 3H),3.74 (s, 2H); 13 C NMR (100 MHz, CDCl 3 ) δ 156.57, 148.80, 142.78, 111.68,109.60, 61.30, 54.34。

[0015] Example 2 Weigh 20 mmol of furfuryl acetate, 0.2 mmol of palladium chloride, 0.4 mmol of 1,3-bis(diphenylphosphino)butane, and 20 mL of methanol respectively, add them to a 100 mL reaction kettle, displace with CO six times, fill with 4 MPa of CO, stir and react at 100 °C for 4 hours, cool, add 10 mmol of internal standard (1,4-dioxane), and analyze by gas chromatography. The yield of methyl furanoacetate is 93%.

[0016] Structural formula of the product: Characterization data of the product methyl furanoacetate: 1 H NMR(400 MHz, CDCl 3 ) δ 7.40 (dd, J J =1.9,0.9 Hz, 1H), 6.38 (dd, J J =3.3, 1.9 Hz, 1H), 6.32 - 6.21 (m, 1H), 3.77 (s, 3H),3.74 (s, 2H); 13 C NMR (100 MHz, CDCl 3) d 156.57, 148.80, 142.78, 111.68, 109.60, 61.30, 54.34 Example 3 Weigh 20 mmol of furfuryl propionate, 0.2 mmol of palladium nitrate, 0.4 mmol of 1,3-bis(diphenylphosphino)pentane, and 20 mL of methanol respectively, add them into a 100 mL reaction kettle, displace with CO six times, fill with 2 MPa of CO, stir and react at 100 °C for 4 hours, cool, add 10 mmol of internal standard (1,4-dioxane), and analyze by gas chromatography. The yield of methyl furanoacetate is 90%.

[0017] Product structural formula: Characterization data of the product methyl furanoacetate: 1 H NMR(400 MHz, CDCl 3 ) d 7.40 (dd, J =1.9, 0.9 Hz, 1H), 6.38 (dd, J =3.3, 1.9 Hz, 1H), 6.32 - 6.21 (m, 1H), 3.77 (s, 3H), 3.74 (s, 2H); 13 C NMR (100 MHz, CDCl 3 ) d 156.57, 148.80, 142.78, 111.68, 109.60, 61.30, 54.34 Example 4 Weigh 30 mmol of furfuryl acetate, 0.8 mmol of palladium bromide, 0.6 mmol of bis(2-diphenylphosphinophenyl) ether, and 30 mL of ethanol respectively, add them into a 100 mL reaction kettle, displace with CO six times, fill with 1 MPa of CO, stir and react at 140 °C for 6 hours, cool, add 10 mmol of internal standard (1,4-dioxane), and analyze by gas chromatography. The yield of ethyl furanoacetate is 90%.

[0018] Product structural formula: Characterization data of the product ethyl furanoacetate: 1 H NMR(400 MHz, CDCl 3 ) d 7.41 (dd, J =1.9, 0.9 Hz, 1H), 6.36 (dd, J =3.3, 1.9 Hz, 1H), 6.30 - 6.25 (m, 1H), 4.14 (dd,J = 5.6, 11.2 Hz, 2H), 3.74 (s, 2H), 1.25 (t, J = 5.6, Hz, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ 156.67, 148.85, 142.82, 111.72, 109.63, 60.30, 34.34, 15.1.

[0019] Example 5 Weigh 200 mmol of furfuryl formate, 2 mmol of palladium chloride, 4 mmol of 1,3-bis(diphenylphosphino)ethane, and 200 mL of methanol respectively, add them to a 1 L reaction kettle, displace with CO six times, charge 4 MPa of CO, stir and react at 120 °C for 4 hours, cool, and distill off the solvent methanol and the product methyl furanoacetate under reduced pressure. Perform chromatographic analysis and record it as the result of the first use (Table 1). Supplement new furfuryl formate and methanol solvent, and repeat the above steps for the 2nd, 3rd, 4th, 5th, and 6th uses respectively. It can be seen from the results in Table 1 that the catalyst system of the present invention has good recyclability and stability.

Claims

1. A low-cost synthesis method of furanacetic acid ester compounds, which uses a Group VIII metal salt and a phosphine ligand as a catalyst, a furanacetic acid ester compound as a raw material, introduces carbon monoxide gas, and performs a carbonylation reaction in an organic solvent to obtain a furanacetic acid ester compound; The structural formula of furfuryl ester compounds is: in, The substituent R is selected from alkyl groups.

2. The method for synthesizing furanacetic acid ester compounds according to claim 1, wherein: The amount of the Group VIII metal salt used is 0.01-10% of the molar amount of the furfuryl ester compound; the molar ratio of the Group VIII metal salt to the phosphine ligand is 1:1-1:

10.

3. The low-cost synthesis method of furanacetic acid ester compounds according to claim 1, characterized in that: The carbonylation reaction temperature is 30-200°C, the pressure is 0.1-6MPa, and the time is 0.5-20 hours.

4. The low-cost synthesis method of furanacetic acid ester compounds according to claim 1, characterized in that: The Group VIII metal salt is selected from at least one of acetate, nitrate, chloride, bromide and acetylacetonate of palladium, platinum, rhodium and ruthenium.

5. The low-cost synthesis method of furanacetic acid ester compounds according to claim 1, characterized in that: The phosphine ligand is selected from at least one of triphenylphosphine, 1,1'-bis(diphenylphosphino)ferrocene, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,5-bis(diphenylphosphino)pentane, 1,6-bis(diphenylphosphino)hexane, tri-tert-butylphosphine, tricyclohexylphosphine, 1,2-bis(diphenylphosphino)benzene, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, bis(2-diphenylphosphinophenyl)ether, tri-p-phenylmethylphosphine, tri(4-fluorophenyl)phosphine, tri(pentafluorophenyl)phosphine, tri(4-chlorophenyl)phosphine, and tri(2-furan)phosphine.

6. The low-cost synthesis method of furanacetic acid ester compounds according to claim 1, characterized in that: The organic solvent is at least one of tetrahydrofuran, ethylene dichloride, methanol, ethanol, propanol, butanol, toluene and cyclohexane.

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