A method for preparing a disubstituted furan compound

Abstract

The present invention provides a method for preparing a compound of formula (I), comprising the steps of contacting a compound having a structure of formula (II) with a catalyst and an oxidant in a solvent to cause a reaction. The method is simple, efficient, produces few by-products, and has a high yield. The structures of the compounds of formula (I) and formula (II) are as follows:

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of high-performance polymer monomers and chemical and pharmaceutical intermediates, and specifically relates to a preparation method of a disubstituted furan compound. Background Art

[0002] Because 2,5-furandicarboxylic acid contains a rigid furan ring and a para-dicarboxylic acid group, it can be directly used in the preparation of high-performance polymers such as polyesters, epoxy resins, polyamides, and polyurethanes. Polymers prepared using furandicarboxylic acid exhibit excellent mechanical properties such as strength, modulus, and creep resistance, as well as higher glass transition temperatures and heat distortion temperatures. Furthermore, 2,5-furandicarboxylic acid or its esters can be used as chemical raw materials and pharmaceutical intermediates. Currently, the main method for synthesizing 2,5-furandicarboxylic acid or its esters uses expensive 5-hydroxymethylfurfural (HMF) as a raw material. This method suffers from low overall yields, difficulty in preparing the raw material HMF, and high costs, making large-scale industrial application difficult. Even if the HMF preparation process is improved and the yield is increased, the starting materials for HMF preparation are fructose and glucose, which are major food ingredients. Large-scale industrial production of HMF would inevitably disrupt the food supply chain.

[0003] In summary, there is an urgent need for a method for synthesizing 2,5-furandicarboxylic acid with low cost, high yield and suitability for industrial production. Summary of the Invention

[0004] The present invention provides a method for preparing a compound of formula (I), comprising the steps of contacting a compound having a structure of formula (II) with a catalyst and an oxidant in a solvent to react, wherein the structure of the compound of formula (I) is:

[0005]

[0006] The structure of the compound of formula (II) is:

[0007]

[0008] Wherein, R1 is selected from the following group: acetyl, methyl, hydroxymethyl, formic acid, formaldehyde, -COOAr, wherein Ar=C1-C10 alkyl;

[0009] R1' is selected from the group consisting of: formic acid, methyl formate, -COOAr, wherein Ar=C1-C10 alkyl.

[0010] In another preferred embodiment, R1 and R1' may be the same or different.

[0011] In another preferred embodiment, the catalyst is selected from the group consisting of metal salts containing Co, Mn or Zr, NaBr, KBr, LiBr, RuBr, CsBr, or a combination thereof; preferably selected from the group consisting of Co carboxylates, Mn carboxylates, Zr carboxylates, NaBr, KBr, LiBr, RuBr, CsBr, or a combination thereof.

[0012] In another preferred embodiment, the cobalt-containing metal salt is selected from the group consisting of cobalt acetate, cobalt formate, cobalt propionate, or a combination thereof.

[0013] In another preferred embodiment, the manganese-containing metal salt is selected from the group consisting of manganese acetate, manganese formate, manganese propionate, or a combination thereof.

[0014] In another preferred embodiment, the catalyst is selected from the group consisting of cobalt acetate, manganese acetate, zirconium acetate, or a combination thereof.

[0015] In another preferred embodiment, the catalyst is selected from the group consisting of NaBr, KBr, LiBr, RuBr, CsBr, or a combination thereof.

[0016] In another preferred embodiment, the catalyst is selected from the group consisting of cobalt acetate, manganese acetate, sodium bromide, or a combination thereof.

[0017] In another preferred embodiment, the catalyst includes a catalyst selected from the following groups (a), (b) and optionally (c): (a) a cobalt-containing metal salt; (b) NaBr, KBr, LiBr, RuBr, CsBr, or a combination thereof; (c) a manganese-containing metal salt.

[0018] In another preferred embodiment, in the catalyst, the molar ratio of the components (a), (b) and (c) is 1:0.5-10:0.5-20.

[0019] In another preferred embodiment, the oxidant is selected from the group consisting of oxygen, oxygen-containing gas (such as air), or a combination thereof.

[0020] In another preferred embodiment, the solvent is selected from the group consisting of C1-C6 carboxylic acids, C2-C12 anhydrides, water, or a combination thereof.

[0021] In another preferred embodiment, the solvent is selected from the group consisting of formic acid, acetic acid, propionic acid, acetic anhydride, or a combination thereof.

[0022] In another preferred embodiment, the solvent is acetic acid.

[0023] In another preferred embodiment, the molar ratio of the catalyst to the compound of formula (II) is 0.1-10%.

[0024] In another preferred embodiment, the molar ratio of the solvent to the compound of formula (II) is 1-20:1.

[0025] In another preferred embodiment, the reaction temperature of the method is 150-250°C.

[0026] In another preferred embodiment, the reaction temperature of the method is 180-220°C.

[0027] In another preferred embodiment, the compound of formula (I) is selected from the following group: 2,5-diacetylfuran, 2-acetyl-5-methylfuran, 2-acetyl-5-hydroxymethylfuran, 2-acetyl-5-furoic acid, 2-acetyl-5-furaldehyde, 2-acetyl-5-furoic acid methyl ester, or a combination thereof.

[0028] In another preferred embodiment, the compound of formula (I) is selected from the following group: 2,5-diacetylfuran, 2-acetyl-5-methylfuran, or a combination thereof.

[0029] In another preferred embodiment, the compound of formula (II) is prepared by the following method:

[0030] The compound of formula (II) is prepared by acylation reaction of raw materials selected from the following group with an acetylating agent: 5-acetylfuran, 5-methylfuran, 5-hydroxymethylfuran, 5-furoic acid, 5-furfural, 5-furoic acid methyl ester, or a combination thereof.

[0031] In another preferred embodiment, the acetylating agent is selected from the group consisting of acetic anhydride, acetyl chloride, or a combination thereof.

[0032] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features described in detail 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 listed here one by one. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The 2,5-furandicarboxylic acid obtained in Example 1 1 H-NMR spectrum. DETAILED DESCRIPTION

[0034] After extensive and in-depth research and extensive screening, the inventors unexpectedly discovered a method for preparing high-purity 2,5-furandicarboxylic acid using a 2-acetylfuran compound as a raw material through an oxidation reaction. This method is simple, efficient, produces few byproducts, and has a high yield. Based on this discovery, the inventors completed the present invention.

[0035] the term

[0036] The term "C1-C10 alkyl" refers to a straight-chain or branched alkyl group containing 1 to 10 carbon atoms, such as methyl, propyl, isopropyl, and the like.

[0037] The term "C1-C6 carboxylic acid" refers to a carboxylic acid containing 1 to 10 carbon atoms, such as formic acid, acetic acid, and the like.

[0038] The term "C2-C12 anhydride" refers to an anhydride containing 2 to 12 carbon atoms, such as acetic anhydride, butyric anhydride, and the like.

[0039] Preparation method of 2,5-furandicarboxylic acid

[0040] The present invention provides a method for preparing a compound of formula (I), comprising the steps of contacting a compound having a structure of formula (II) with a catalyst and an oxidant in a solvent to react, wherein the structure of the compound of formula (I) is:

[0041]

[0042] The structure of the compound of formula (II) is:

[0043]

[0044] In the formula, R1 is a substituent selected from the group consisting of acetyl, methyl, hydroxymethyl, formate, formaldehyde, -COOAr, wherein Ar = C1-C10 alkyl;

[0045] R1' is a substituent selected from the group consisting of: formic acid, methyl formate, -COOAr, wherein Ar = C1-C10 alkyl;

[0046] In another preferred embodiment, R1 and R1' may be the same or different.

[0047] The catalyst used in the reaction can be any one or more of the following catalysts. Preferably, it is a metal salt containing Co, Mn or Zr, or a catalyst selected from the group consisting of NaBr, KBr, LiBr, RuBr, CsBr, or a combination thereof. The metal salt containing Co, Mn or Zr is preferably a Co carboxylate, a Mn carboxylate, or a Zr carboxylate. The cobalt-containing metal salt is preferably selected from the group consisting of cobalt acetate, cobalt formate, cobalt propionate, or a combination thereof. The manganese-containing metal salt is preferably selected from the group consisting of manganese acetate, manganese formate, manganese propionate, or a combination thereof. The zirconium-containing metal salt is preferably zirconium acetate.

[0048] In a preferred embodiment, the catalyst is selected from the group consisting of cobalt acetate, manganese acetate, zirconium acetate, or a combination thereof. More preferably, the catalyst is selected from the group consisting of cobalt acetate, manganese acetate, sodium bromide, or a combination thereof.

[0049] In another preferred embodiment, the catalyst comprises a catalyst selected from the group consisting of (a), (b), and optionally (c): (a) a cobalt-containing metal salt; (b) NaBr, KBr, LiBr, RuBr, CsBr, or a combination thereof; and (c) a manganese-containing metal salt. The molar ratio of components (a), (b), and (c) is preferably 1:0.5-10:0.5-20.

[0050] The oxidant introduced into the reaction is not particularly limited and may be oxygen or an oxygen-containing gas (such as air), and other components in the oxygen-containing gas do not participate in the reaction.

[0051] The solvent used in the reaction can be a solvent selected from the group consisting of a C1-C6 carboxylic acid, a C2-C12 anhydride, water, or a combination thereof. Preferably, the solvent is formic acid, acetic acid, propionic acid, acetic anhydride, or a combination thereof. More preferably, the solvent is acetic acid.

[0052] In a preferred embodiment, the molar ratio of the catalyst to the compound of formula (II) is 0.1-10%, and the molar ratio of the solvent to the compound of formula (II) is 1-20:1.

[0053] In a preferred embodiment, the method requires heating, and the preferred reaction temperature is 150-250°C, more preferably 180-220°C.

[0054] In a preferred embodiment, the compound of formula (I) is a compound selected from the group consisting of 2,5-diacetylfuran, 2-acetyl-5-methylfuran, 2-acetyl-5-hydroxymethylfuran, 2-acetyl-5-furoic acid, 2-acetyl-5-furaldehyde, 2-acetyl-5-furoic acid methyl ester, or a combination thereof. More preferably, the compound of formula (I) is 2,5-diacetylfuran, 2-acetyl-5-methylfuran, or a combination thereof.

[0055] In a preferred embodiment, the compound of formula (II) is prepared by acylation reaction of a raw material selected from the group consisting of 5-acetylfuran, 5-methylfuran, 5-hydroxymethylfuran, 5-furoic acid, 5-furfural, 5-furoic acid methyl ester, or a combination thereof. Preferably, the acetylating agent is acetic anhydride, acetyl chloride, or a combination thereof.

[0056] application

[0057] The method of the present invention can be used to synthesize 2,5-furandicarboxylic acid with high yield. In addition, the high-purity 2,5-furandicarboxylic acid prepared by the method of the present invention can be used as a raw material for polymers such as high-performance polyesters, epoxy resins, polyamides, and polyurethanes, as well as a chemical raw material and a pharmaceutical intermediate raw material.

[0058] The main advantages of the present invention include:

[0059] The method for preparing 2,5-furandicarboxylic acid, described herein, uses 2-acetyl-5-furoic acid or its esters as a raw material to produce high-purity 2,5-furandicarboxylic acid, thereby opening up a new technical route for synthesizing high-performance engineering materials from furan compounds. Because the furan raw material can be derived from bio-based sources, it can help the bio-based polymer materials industry gradually break away from its dependence on petroleum resources and promote the sustainable development of the entire polymer materials industry.

[0060] The method of the present invention is simple and efficient, has a short process, and produces few by-products. The total yield of the product can reach 70%-99%, and the purity is high. It is suitable for large-scale industrial production and can meet the requirements of being a raw material for high-performance polyesters, epoxy resins, polyamides, polyurethanes and other polymers, as well as a chemical raw material and a pharmaceutical intermediate raw material.

[0061] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples, for which specific conditions are not specified, are generally based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0062] General Methods

[0063] In the following examples, 1H-NMR was measured using a Bruker 400AVANCE III spectrometer (400 MHz) with dimethyl sulfoxide (DMSO), and product analysis was performed using an Agilent 7890B-5977A liquid chromatography-mass spectrometer.

[0064] Example 1

[0065] In a 500ml reactor, 3.08g of 2-acetyl-5-furoic acid, 15.6ml of acetic acid, 2mmol of cobalt acetate, 5mmol of manganese acetate and 10mmol of sodium bromide were added, oxygen was introduced, and the reaction was carried out at 180℃ for 6h. The precipitated solid was filtered and dried to obtain 2,5-furandicarboxylic acid with a yield of 88%. 1 H-NMR (400MHz, DMSO) test showed that the furan ring CH, 2H, δ (7.28); carboxyl OH, 2H, δ (13.60), such as Figure 1 As shown, the molecular weight was determined to be 156.1 by liquid chromatography-mass spectrometry (LC-MS).

[0066] Example 2

[0067] In a 500ml reactor, 3.08g of 2-acetyl-5-furoic acid, 7.8ml of acetic acid, 4mmol of cobalt acetate, 8mmol of manganese acetate, and 20mmol of sodium bromide were added. Air was purged and the reaction was carried out at 200°C for 10 hours. The precipitated solid was filtered and dried to obtain 2,5-furandicarboxylic acid in an 85% yield. 1H-NMR (400MHz, DMSO) analysis revealed CH on the furan ring, 2H, δ(7.28); and OH on the carboxyl group, 2H, δ(13.60). Liquid chromatography-mass spectrometry (LC-MS) revealed a molecular weight of 156.1. HPLC analysis determined the purity of the 2,5-furandicarboxylic acid to be 99.1%.

[0068] Example 3

[0069] In a 500ml reactor, 3.08g of 2-acetyl-5-furoic acid, 3.9ml of acetic acid, 8mmol of cobalt acetate, 8mmol of manganese acetate, and 10mmol of sodium bromide were added. Oxygen was introduced and the reaction was carried out at 220°C for 8h. The precipitated solid was filtered and dried to obtain 2,5-furandicarboxylic acid in a 72% yield. 1H-NMR (400MHz, DMSO) analysis revealed CH on the furan ring, 2H, δ(7.28); and OH, 2H, δ(13.60). Liquid chromatography-mass spectrometry (LC-MS) revealed a molecular weight of 156.1. HPLC analysis of the 2,5-furandicarboxylic acid yielded a purity of 89.4%.

[0070] Example 4

[0071] In a 500ml reactor, 3.08g of 2-acetyl-5-furoic acid, 31.2ml of acetic acid, 8mmol of cobalt acetate, 16mmol of manganese acetate, and 30mmol of sodium bromide were added. Oxygen was introduced and the reaction was carried out at 240°C for 6h. The precipitated solid was filtered and dried to obtain 2,5-furandicarboxylic acid in a 98% yield. 1H-NMR (400MHz, DMSO) analysis revealed CH on the furan ring, 2H, δ(7.28); and OH, 2H, δ(13.60). Liquid chromatography-mass spectrometry (LC-MS) revealed a molecular weight of 156.1. HPLC analysis of the 2,5-furandicarboxylic acid revealed a purity of 99.8%.

[0072] Example 5

[0073] In a 500ml reactor, 3.08g of 2-acetyl-5-furoic acid, 31.2ml of acetic acid, 1mmol of cobalt acetate, 2mmol of manganese acetate, and 5mmol of sodium bromide were added. Air was allowed to circulate and the reaction was carried out at 260°C for 4h. The precipitated solid was filtered and dried to obtain 2,5-furandicarboxylic acid in an 84% yield. 1H-NMR (400MHz, DMSO) analysis revealed CH on the furan ring, 2H, δ(7.28); and OH, 2H, δ(13.60). Liquid chromatography-mass spectrometry (LC-MS) revealed a molecular weight of 156.1. HPLC analysis of the 2,5-furandicarboxylic acid revealed a purity of 99.3%.

[0074] Example 6

[0075] In a 500ml reactor, 3.08g of 2-acetyl-5-furoic acid, 31.2ml of acetic acid, 5mmol of cobalt acetate, 6mmol of manganese acetate, and 10mmol of sodium bromide were added. Oxygen was introduced and the reaction was carried out at 150°C for 14h. The precipitated solid was filtered and dried to obtain 2,5-furandicarboxylic acid in a 78% yield. 1H-NMR (400MHz, DMSO) analysis revealed CH on the furan ring, 2H, δ(7.28); and OH, 2H, δ(13.60). Liquid chromatography-mass spectrometry (LC-MS) revealed a molecular weight of 156.1. HPLC analysis determined the purity of the 2,5-furandicarboxylic acid to be 99.0%.

[0076] All documents mentioned in this application are incorporated herein by reference, just as if each document were incorporated herein by reference individually. It should also be understood that after reading the above teachings of the present invention, those skilled in the art may make various changes or modifications to the present invention, and that such equivalents also fall within the scope of the claims appended hereto.

Claims

1. A method for preparing 2,5-furandicarboxylic acid, characterized in that: The method comprises the following steps: adding 3.08 g of 2-acetyl-5-furoic acid, 31.2 ml of acetic acid, 8 mmol of cobalt acetate, 16 mmol of manganese acetate and 30 mmol of sodium bromide into a 500 ml reactor, introducing oxygen, reacting at 240° C. for 6 hours, filtering the precipitated solid and drying it to obtain 2,5-furandicarboxylic acid.

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