Novel furan structure bio-based Schiff base epoxy resin and preparation method thereof
A novel furan structure bio-based Schiff base epoxy resin addresses the mechanical weakness of existing bio-based resins by employing furan structure biomass, resulting in a thermosetting resin with improved mechanical properties and reduced petrochemical dependence.
Patent Information
- Application Number
- CN202410598430.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2024-12-27
AI Technical Summary
Existing bio-based epoxy resins suffer from poor mechanical properties, limiting their application due to reliance on petroleum-based raw materials and causing environmental concerns.
A novel furan structure bio-based Schiff base epoxy resin is synthesized using furan structure biomass, involving specific reaction steps with amino compounds and aldehyde furan structure-containing bio-based phenol monomers, followed by reaction with epichlorohydrin and a curing agent, to produce a thermosetting resin with improved mechanical properties.
The synthesis process is efficient and yields a resin with enhanced mechanical strength, reducing reliance on petrochemical resources and promoting green environmental protection.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of thermosetting resins, and in particular to a novel furan structure bio-based Schiff base epoxy resin and a preparation method thereof. Background Art
[0002] Epoxy resin (EP) is a kind of high molecular thermosetting material with a wide range of applications. It is widely used in coatings, adhesives, electronic and electrical sealants, electronic information, polymer composite materials and other fields because of its excellent adhesion and chemical resistance, excellent strength and mechanical properties, good processing performance and dimensional stability. However, the existing epoxy resins are basically made from petroleum-based raw materials, and more than 85% of the total output of epoxy resins is made from bisphenol A and epichlorohydrin. Although epichlorohydrin can be converted from bio-based raw materials glycerol, bisphenol A can only be prepared from petroleum-based raw materials at present. Petroleum resources have been consumed in large quantities, and at the same time, a series of severe environmental problems have been brought about, which have brought great pressure to the development of epoxy resins with petroleum resources as the main raw materials. In order to reduce the dependence on petrochemical products and reduce the emission of CO2, the development of bio-based thermosetting resins through a series of chemical, biological or physical transformations using renewable resources such as starch and cellulose as starting materials has attracted much attention. In recent years, the development of bio-based epoxy resins has mainly relied on rosin acid, furanic acid, furan compounds and vegetable oils. The above-mentioned bio-based thermosetting resins reported in the literature generally have the problem of poor mechanical properties, which greatly limits their application.
[0003] Furan rings can be widely derived from biomass resources, such as furfural can be extracted from plant fibers, from which more bio-based monomers containing furan rings can be derived. Since furan rings have higher rigidity than benzene rings, if they are introduced into the structure of macromolecules, it is expected to prepare polymer materials with higher rigidity. There are also relevant reports in the literature, such as Zhu Jin et al. prepared furan epoxy resins with flexible chain segments in the side chains. (Shen Xiaobin, Zhu Jin, et al. Synthesis of an Epoxy Monomer from Bio-Based 2, 5-Furandimethanol and It Toughening via Diels-Alder Reaclion. Tnd. Fng. Chem. Res. 2017, 56, 30, 8508-8516) Summary of the invention
[0004] In order to solve the problem of poor mechanical properties in the prior art, the present invention provides a novel furan structure bio-based Schiff base epoxy resin synthesized from furan structure biomass and a preparation method thereof, which conforms to the concept of green environmental protection and sustainable development, and the preparation method is simple and easy to implement.
[0005] The technical solution adopted by the present invention is as follows:
[0006] 1. A method for preparing a novel furan structure bio-based Schiff base epoxy resin, comprising the following steps:
[0007] Dissolve the amino compound in solvent S, then add dropwise the solution of the aldehyde furan structure-containing bio-based phenol monomer, add the amino group in the amino compound and the aldehyde group in the aldehyde furan structure-containing bio-based phenol monomer in a molar ratio of 1: (2-2.5), heat to 50℃-80℃, react for 6-12h, cool to room temperature, pour into an appropriate amount of distilled water, extract with ethyl acetate, shake thoroughly to mix, and then stand to separate. The product dissolved in ethyl acetate is in the upper layer, and the excess aldehyde furan structure-containing bio-based phenol monomer is in the lower layer. Separate the liquids, take the ethyl acetate layer and dry it with anhydrous sodium sulfate, remove the water, and leave it overnight. Distill under reduced pressure to remove most of the ethyl acetate and solvent S, dry under vacuum to remove the remaining trace of ethyl acetate and solvent S, and obtain the furan structure-containing bio-based Schiff base phenol monomer (DAF);
[0008] DAF, phase transfer catalyst T and epichlorohydrin are added in a molar ratio of 1: (0.001-0.5): (10-100), the temperature is raised to 60-100°C and the reaction is carried out for 2-8 hours, and then a sodium hydroxide aqueous solution with a mass fraction of 20wt%-50wt% is added dropwise to the system, and the reaction is carried out at 25°C-60°C for 2-6 hours. After the reaction is completed, the generated sodium chloride is removed by suction filtration, and the filtrate is extracted with distilled water to remove the phase transfer catalyst T, and the liquid is separated three times. The organic layer is taken and dried with anhydrous sodium sulfate, and the water is removed and left overnight. Most of the excess epichlorohydrin and water are removed by vacuum distillation, and the product is placed in a vacuum oven at 90°C to dry, and the remaining trace epichlorohydrin and water are removed to obtain a new type of furan structure bio-based Schiff base epoxy monomer (DAFP);
[0009] DAFP and curing agent A are mixed in a molar ratio of 1:(0.5-2), vacuum degassing is performed, and after no bubbles are present, the mixture is poured into a mold, and cured at 60-100°C for 1-4 hours and at 100-140°C for 2-6 hours for thermosetting molding to obtain a novel furan structure bio-based Schiff base epoxy resin (DAFPA).
[0010] 2. The structure of the novel furan-structured bio-based Schiff base epoxy resin described in 1 of the specification is one or more of the following:
[0011] a.
[0012] b.
[0013] c.
[0015] Wherein, R1 is one or more of hydrogen, methyl, propenyl, phenyl, methylphenyl, carboxylic acid methyl ester; R2 is one of methylene, ether, sulfonyl. The values of n1 and n2 are 0 to 6; the value of n3 is 2 to 6.
[0016] 3. A novel method for preparing a furan structure bio-based Schiff base epoxy resin according to Instruction 1, characterized in that the solvent S is one of ethanol, tetrahydrofuran or acetone.
[0017] 4. A novel method for preparing a furan-structured bio-based Schiff base epoxy resin according to 1 in the specification, characterized in that the phase transfer catalyst T is one of benzyltriethylammonium chloride (TEBA), tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride.
[0018] 5. A novel method for preparing a furan-structured bio-based Schiff base epoxy resin according to 1 in the specification, characterized in that the curing agent A is one or a mixture of two or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, isophoronediamine, N-aminoethylpiperazine, bis(4-aminocyclohexyl)methane, trioctylmethylamine, diaminodiphenylmethane, diaminodiphenyl sulfone, m-phenylenediamine, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecenylsuccinic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, ethylene glycol ditrimellitic anhydride, methylcyclohexenyltetracarboxylic anhydride, and trimellitic anhydride.
[0019] 6. A novel method for preparing a furan-structured bio-based Schiff base epoxy resin according to 1 in the specification, characterized in that the aldehyde-containing furan-structured bio-based phenolic monomer in the furan-structured bio-based Schiff base phenolic monomer (DAF) is one or more of 5-hydroxy-2-furaldehyde, 5-hydroxymethylfurfural, 5-hydroxymethyl-3-methyl-2-furaldehyde, 5-(4-hydroxybutyl)-2-furaldehyde, 5-(2-hydroxyethyl)-3-furaldehyde, 5-(6-hydroxyhexyl)-2-furaldehyde, 5-hydroxymethyl-3-(2-propen-1-yl)-2-furaldehyde, 5-hydroxymethyl-3-phenyl-2-furaldehyde, 5-hydroxymethyl-3-(3-methylphenyl)-2-furaldehyde, and 2-formyl-5-hydroxymethyl-3-furancarboxylic acid methyl ester.
[0020] 7. A novel method for preparing a furan structure bio-based Schiff base epoxy resin according to 1 in the specification, characterized in that the amino compound in the furan structure bio-based Schiff base phenolic monomer (DAF) is one or more of ethylenediamine, hexamethylenediamine, 1,5-pentanediamine, 1,3-propylenediamine, 1,4-butylenediamine, 4,4'-diaminodicyclohexylmethane, 4,4'-sulfonylbis[cyclohexylamine], bis(4-aminocyclohexyl) ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether or 4,4'-diaminodiphenyl sulfone.
[0021] The present invention has the following advantages and effects:
[0022] 1. The synthesis process of the novel furan structure bio-based Schiff base epoxy monomer (DAFP) in 1 of the specification of the present invention is easy to implement and has a high yield of the product after synthesis;
[0023] 2. The novel furan structure bio-based Schiff base epoxy resin (DAFPA) provided by the present invention makes up for the common defect of insufficient mechanical properties compared with the bio-based epoxy resins reported previously.
[0024] 3. The novel furan-structured bio-based Schiff base epoxy resin (DAFPA) provided by the present invention is completely converted from furan-structured biomass monomers, which meets the goal of saving petrochemical resources and green environmental protection and sustainable development; DETAILED DESCRIPTION
[0025] In order to better understand the present invention, the content of the present invention is further explained in conjunction with the following examples, but the content of the present invention is not limited to the following examples, and the examples should not be regarded as limiting the scope of protection of the present invention.
[0026] Example 1
[0027] Add 0.6g of ethylenediamine to a 100mL three-necked flask, add 20mL of anhydrous ethanol, stir mechanically until completely dissolved, then add 2.47g of 5-hydroxy-2-furan formaldehyde solution dissolved in 30mL of anhydrous ethanol dropwise, and the system reacts at 75°C for 6h. After the reaction is completed, pour the system into an appropriate amount of distilled water, extract with ethyl acetate, shake thoroughly to mix, and then stand for stratification. EAF dissolved in ethyl acetate is on the upper layer, and excess ethylenediamine is on the lower layer. Separate the liquid, take the ethyl acetate layer and dry it with anhydrous sodium sulfate, remove water, and leave it overnight. Remove most of the ethyl acetate and anhydrous ethanol by vacuum distillation, dry in a vacuum oven at 50°C to remove the remaining traces of ethyl acetate and anhydrous ethanol. Obtain a furan structure-containing bio-based Schiff base phenol monomer (EAF) with a yield of 93%.
[0028] In a 250mL three-necked flask equipped with mechanical stirring and condensation reflux, 1.87g of EAF, 0.5g of tetrabutylammonium bromide and 10.2g of epichlorohydrin were added in sequence, and the temperature was raised to 90°C for 6h. Then 4mL of a 20% (w / w) NaOH aqueous solution was added dropwise to the system, and the reaction was continued at 60°C for 6h. After the reaction was completed, the filtrate was filtered and extracted with distilled water to remove tetrabutylammonium bromide. The liquid was separated three times, and the organic layer was added with anhydrous sodium sulfate to dry, and the water was removed and left overnight. Most of the excess epichlorohydrin and water were removed by vacuum distillation, and the product was placed in a vacuum oven at 90°C to dry, and the remaining trace epichlorohydrin and water were removed to obtain a new type of furan structure bio-based Schiff base epoxy monomer (EAFP) with a yield of 89%.
[0029] The obtained EAFP epoxy monomer and curing agent DDM were mixed evenly in a molar ratio of epoxy to NH:1, vacuum degassing was performed, and after no bubbles were present, the mixture was poured into a mold and cured at 100°C for 2h and 120°C for 4h to obtain a new type of furan structure bio-based Schiff base epoxy resin (EAFPD). After natural cooling, a brick-red epoxy resin polymer specimen was obtained. The obtained specimen was used to test the mechanical properties, and the tensile strength reached 59.8±1.5MPa.
[0030] Example 2
[0031] Add 2.1g 4,4'-diaminodicyclohexylmethane to a 100mL three-necked flask, add 20mL tetrahydrofuran, stir mechanically until completely dissolved, then add 3.08g 5-hydroxymethyl-3-methyl-2-furan formaldehyde solution dissolved in 30mL tetrahydrofuran dropwise, and the system reacts at 65°C for 8h. After the reaction is completed, pour the system into an appropriate amount of distilled water, extract with ethyl acetate, shake thoroughly to mix, and then stand for stratification. DMF dissolved in ethyl acetate is on the upper layer, and excess 4,4'-diaminodicyclohexylmethane is on the lower layer. Separate the liquid, take the ethyl acetate layer and dry it with anhydrous sodium sulfate, remove water, and leave it overnight. Remove most of the ethyl acetate and tetrahydrofuran by vacuum distillation, and dry in a vacuum oven at 50°C to remove the remaining traces of ethyl acetate and tetrahydrofuran. Obtain a bio-based Schiff base phenol monomer (DMF) containing a furan structure with a yield of 96%.
[0032] In a 250mL three-necked flask equipped with mechanical stirring and condensation reflux, 4.36g of DMF, 0.5g of tetrabutylammonium bromide and 10.2g of epichlorohydrin were added in sequence, the temperature was raised to 90°C, and the reaction was continued for 6h. Subsequently, 4mL of a 20% (w / w) NaOH aqueous solution was added dropwise to the system, and the reaction was continued at 60°C for 6h. After the reaction was completed, the generated sodium chloride was removed by suction filtration, and the filtrate was extracted with distilled water to remove tetrabutylammonium bromide. The liquid was separated three times, and the organic layer was added with anhydrous sodium sulfate to dry, and the water was removed and placed overnight. Most of the excess epichlorohydrin and water were removed by reduced pressure distillation, and the product was placed in a vacuum oven at 90°C to dry, and the remaining trace epichlorohydrin and water were removed to obtain a new type of furan structure bio-based Schiff base epoxy monomer (DMFP) with a yield of 90%.
[0033] The obtained DMFP epoxy monomer and curing agent m-phenylenediamine were mixed evenly in a molar ratio of epoxy to NH:1, vacuum degassing was performed, and after no bubbles were present, the mixture was poured into a mold and cured at 100°C for 2h and 120°C for 4h to obtain a new type of furan structure bio-based Schiff base epoxy resin (DMFPM). After natural cooling, a brick-red epoxy resin polymer specimen was obtained. The obtained specimen was used to test the mechanical properties, and the tensile strength reached 60.4±2.4MPa.
[0034] Example 3
[0035] Add 2.48g 4,4'-diaminodiphenyl sulfone to a 100mL three-necked flask, add 20mL acetone, stir mechanically until completely dissolved, then add 2.77g 5-hydroxymethylfurfural solution dissolved in 30mL acetone dropwise, and the system reacts at 55°C for 12h. After the reaction is completed, pour the system into an appropriate amount of distilled water, extract with ethyl acetate, shake thoroughly to mix, and then stand for stratification. SAF dissolved in ethyl acetate is on the upper layer, and excess 4,4'-diaminodiphenyl sulfone is on the lower layer. Separate the liquid, take the ethyl acetate layer and dry it with anhydrous sodium sulfate, remove water, and leave it overnight. Remove most of the ethyl acetate and acetone by vacuum distillation, dry in a vacuum oven at 50°C to remove the remaining traces of ethyl acetate and acetone. Obtain a furan structure-containing bio-based Schiff base phenol monomer (SAF) with a yield of 95%.
[0036] In a 250mL three-necked flask equipped with mechanical stirring and condensation reflux, 4.56g of SMF, 0.5g of tetrabutylammonium bromide and 10.2g of epichlorohydrin were added in sequence, the temperature was raised to 90°C, and the reaction was continued for 6h. Subsequently, 4mL of a 20% (w / w) NaOH aqueous solution was added dropwise to the system, and the reaction was continued at 60°C for 6h. After the reaction was completed, the generated sodium chloride was removed by suction filtration, and the filtrate was extracted with distilled water to remove tetrabutylammonium bromide. The liquid was separated three times, and the organic layer was added with anhydrous sodium sulfate to dry, and the water was removed and left overnight. Most of the excess epichlorohydrin and water were removed by reduced pressure distillation, and the product was placed in a vacuum oven at 90°C to dry, and the remaining trace epichlorohydrin and water were removed to obtain a new type of furan structure bio-based Schiff base epoxy monomer (SAFP) with a yield of 91%.
[0037] The obtained SAFP epoxy monomer and curing agent isophorone diamine were mixed evenly in a molar ratio of epoxy to NH:1, and vacuum degassing was performed. After no bubbles were left, the system was poured into a mold and cured at 100°C for 2h and 120°C for 4h to obtain a new type of furan structure bio-based Schiff base epoxy resin (SAFPI). After natural cooling, a brick-red epoxy resin polymer specimen was obtained. The obtained specimen was used to test the mechanical properties, and the tensile strength reached 60.4±4.2MP.
[0038] Example 4
[0039] In a 100mL three-necked flask, add 1.98g 4,4'-diaminodiphenyl sulfone, add 20mL of anhydrous ethanol, stir mechanically until completely dissolved, then add dropwise a solution of 4.45g 5-hydroxymethyl-3-phenyl-2-furan carboxaldehyde dissolved in 30mL of anhydrous ethanol, and the system reacts at 75°C for 6h. After the reaction is completed, pour the system into an appropriate amount of distilled water, extract with ethyl acetate, shake thoroughly to mix, and then stand for stratification. DSF dissolved in ethyl acetate is on the upper layer, and excess 4,4'-diaminodiphenyl sulfone is on the lower layer. Separate the liquid, take the ethyl acetate layer and dry it with anhydrous sodium sulfate, remove water, and leave it overnight. Remove most of the ethyl acetate and anhydrous ethanol by vacuum distillation, and dry it in a vacuum oven at 50°C to remove the remaining traces of ethyl acetate and anhydrous ethanol. Obtain a furan structure-containing bio-based Schiff base phenol monomer (DSF) with a yield of 96%.
[0040] In a three-necked flask equipped with mechanical stirring and condensation reflux, 5.6g of DPF, 0.5g of tetrabutylammonium bromide and 10.2g of epichlorohydrin were added in sequence, the temperature was raised to 90°C, and the reaction was continued for 6h. Subsequently, 4mL of a 20% (w / w) NaOH aqueous solution was added dropwise to the system, and the reaction was continued at 60°C for 6h. After the reaction was completed, the generated sodium chloride was removed by suction filtration, and the filtrate was extracted with distilled water to remove tetrabutylammonium bromide. The liquid was separated three times, and the organic layer was added with anhydrous sodium sulfate to dry, and the water was removed and left overnight. Most of the excess epichlorohydrin and water were removed by reduced pressure distillation, and the product was placed in a vacuum oven at 90°C to dry, and the remaining trace epichlorohydrin and water were removed to obtain a new type of furan structure bio-based Schiff base epoxy monomer (DSFP) with a yield of 88%.
[0041] The obtained DSFP epoxy monomer and curing agent 4,4'-diaminodiphenyl ether were mixed evenly in a molar ratio of 1:1 between epoxy and NH, and then vacuum degassing was performed. After no bubbles were left, the system was poured into a mold and cured at 100°C for 2h and 120°C for 4h to obtain a new type of furan structure bio-based Schiff base epoxy resin (DSFPM). After natural cooling, a brick-red epoxy resin polymer specimen was obtained. The obtained specimen was used to test the mechanical properties, and the tensile strength reached 62.4±8.2MP.
Claims
1. A method for preparing a novel furan structure bio-based Schiff base epoxy resin, comprising the following steps: Dissolve the amino compound in solvent S, then add dropwise the solution of the aldehyde furan structure-containing bio-based phenol monomer, add the amino group in the amino compound and the aldehyde group in the aldehyde furan structure-containing bio-based phenol monomer in a molar ratio of 1: (2-2.5), heat to 50°C-80°C, react for 6-12 hours, cool to room temperature, pour into an appropriate amount of distilled water, extract with ethyl acetate, shake thoroughly to mix, and then stand to separate. The product dissolved in ethyl acetate is in the upper layer, and the excess aldehyde furan structure-containing bio-based phenol monomer is in the lower layer. Separate the liquids, take the ethyl acetate layer and dry it with anhydrous sodium sulfate, remove the water, and leave it overnight. Distill under reduced pressure to remove most of the ethyl acetate and solvent S, dry under vacuum to remove the remaining trace ethyl acetate and solvent S, and obtain the furan structure-containing bio-based Schiff base phenol monomer (DAF); DAF, phase transfer catalyst T and epichlorohydrin are added in a molar ratio of 1: (0.001-0.5): (10-100), the temperature is raised to 60-100°C for reaction for 2-8h, and then a sodium hydroxide aqueous solution with a mass fraction of 20wt%-50wt% is added dropwise to the system, and the reaction is carried out at 25°C-60°C for 2-6h. After the reaction is completed, the generated sodium chloride is removed by suction filtration, and the filtrate is extracted with distilled water to remove the phase transfer catalyst T, and the liquid is separated three times. The organic layer is taken and dried with anhydrous sodium sulfate, and the water is removed and left overnight. The excess epichlorohydrin and water are removed by vacuum distillation, and the product is placed in a vacuum oven at 90°C for drying to remove the remaining trace epichlorohydrin and water, thereby obtaining a novel furan structure bio-based Schiff base epoxy monomer (DAFP); DAFP and curing agent A are mixed in a molar ratio of 1:(0.5-2), vacuum degassing is performed, and after no bubbles are present, the mixture is poured into a mold, and cured at 60-100°C for 1-4 hours and at 100-140°C for 2-6 hours for thermosetting molding to obtain a novel furan structure bio-based Schiff base epoxy resin (DAFPA).
2. The structure of the novel furan structure bio-based Schiff base epoxy resin according to claim 1 is one or more of the following: a. b. c. in, R1 is one or more of hydrogen, methyl, propenyl, phenyl, methylphenyl, carboxylic acid methyl ester; R2 is one of methylene, ether, sulfonyl. n1 and n2 are 0 to 6; n3 is 2 to 6.
3. A novel method for preparing a furan structure bio-based Schiff base epoxy resin according to claim 1, characterized in that: The solvent S is one of ethanol, tetrahydrofuran or acetone.
4. A novel method for preparing a furan structure bio-based Schiff base epoxy resin according to claim 1, characterized in that: The phase transfer catalyst T is one of benzyltriethylammonium chloride (TEBA), tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride.
5. A novel method for preparing a furan structure bio-based Schiff base epoxy resin according to claim 1, characterized in that: Curing agent A is one or a mixture of two or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, isophoronediamine, N-aminoethylpiperazine, bis(4-aminocyclohexyl)methane, trioctylmethylamine, diaminodiphenylmethane, diaminodiphenyl sulfone, m-phenylenediamine, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecenylsuccinic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, ethylene glycol ditrimellitic anhydride, methylcyclohexenyl tetracarboxylic dianhydride, and trimellitic anhydride.
6. A novel method for preparing a furan structure bio-based Schiff base epoxy resin according to claim 1, characterized in that: The aldehyde-containing furan structure bio-based phenolic monomers in the furan structure-containing bio-based Schiff base phenolic monomers (DAF) are one or more of 5-hydroxy-2-furaldehyde, 5-hydroxymethylfurfural, 5-hydroxymethyl-3-methyl-2-furaldehyde, 5-(4-hydroxybutyl)-2-furaldehyde, 5-(2-hydroxyethyl)-3-furaldehyde, 5-(6-hydroxyhexyl)-2-furaldehyde, 5-hydroxymethyl-3-(2-propen-1-yl)-2-furaldehyde, 5-hydroxymethyl-3-phenyl-2-furaldehyde, 5-hydroxymethyl-3-(3-methylphenyl)-2-furaldehyde, and 2-formyl-5-hydroxymethyl-3-furancarboxylic acid methyl ester.
7. A novel method for preparing a furan structure bio-based Schiff base epoxy resin according to claim 1, characterized in that: The amino compound in the furan structure-containing bio-based Schiff base phenol monomer (DAF) is one or more of ethylenediamine, hexamethylenediamine, 1,5-pentanediamine, 1,3-propylenediamine, 1,4-butylenediamine, 4,4'-diaminodicyclohexylmethane, 4,4'-sulfonylbis[cyclohexylamine], bis(4-aminocyclohexyl)ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether or 4,4'-diaminodiphenyl sulfone.