A bio-based epoxy resin and a method of making the same

Abstract

The application discloses a kind of bio-based epoxy resin and preparation method thereof, belong to chemical industry field.The application uses biogenic succinic acid dimethyl butanedioate and epoxy chloropropane as raw material, by aromatization reaction preparation obtains containing compound 2, 5-dihydroxy terephthalic acid dimethyl ester of bisphenol hydroxyl, again by epoxy chloropropane reaction preparation epoxy resin monomer, and the monomer is cured.The application provides by the 2, 5-dihydroxy terephthalic acid dimethyl ester and epoxy chloropropane reaction obtained bio-based epoxy resin monomer, and with curing agent reaction, obtain bio-based epoxy resin, the bio-based epoxy resin novel structure, excellent performance has green, environmental protection and the like advantages, has the dual effect of saving petroleum resources and protecting environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical industry and fine chemicals, and relates to a synthesis method of an epoxy resin containing 2,5-dihydroxy terephthalic acid dimethyl ester structure. BACKGROUND

[0002] Epoxy resin is a very popular polymer. Due to its excellent mechanical properties, high adhesion strength, excellent thermal stability, low cost and good processing performance, it is widely used in aerospace, protective coating, electronic communication and building materials and other fields. According to the "China Epoxy Resin Industry Production and Sales Demand and Investment Forecast Analysis Report", the global epoxy resin production capacity in 2019 was 4.96 million tons / year. China is the world's largest producer of epoxy resin, and also the world's largest consumer of epoxy resin.

[0003] Bisphenol A diglycidyl ether (DGEBA) is the main commercial epoxy resin, which has excellent chemical and mechanical properties, but this epoxy resin is mainly prepared from fossil resources, and its raw material bisphenol A (BPA) has been proved to have impact on human health and environment (Biotechnol Adv. 2018; 36(1): 311-327), and its preparation route is as follows:

[0004]

[0005] In recent years, the synthesis of new polymer materials from renewable resources instead of petroleum-derived polymer materials has become a rapidly developing field, which alleviates the rapid consumption of petroleum resources (Science. 2017, 358(6365): 868-870). Lignin is the most abundant natural aromatic polymer on earth, which is composed of three phenylpropane units, namely guaiacyl (G-type lignin), syringyl (S-type lignin) and p-hydroxyphenyl (H-type lignin). With lignin derivative syringaresinol and diethyl phosphate as raw materials, and diamine as coupling agent, two kinds of resin monomers were prepared by phosphine addition and reaction with epoxy chloropropane, respectively (Macromolecules. 2017, 50(5): 1892-1901). The limiting oxygen index of the cured bio-based epoxy resin is 31.4% and 32.8%, the glass transition temperature is 214℃, the tensile strength is 30.8Mpa, and the tensile modulus is 2709MPa, which are much higher than those of bisphenol A diglycidyl ether (DGEBA) system.

[0006] Chinese patent CN102206324A introduces a kind of full biological epoxy resin and its preparation method, the resin has good mechanical properties, good UV resistance and excellent aging resistance and other characteristics, especially suitable for preparing biological composite matrix resin and outdoor electrical insulating material.Chinese patent CN102796063A introduces a preparation method of a new type of monohydroxy biological epoxy resin, the new epoxy resin has the characteristics of green renewable raw material, simple synthesis process, good stability and good heat resistance and electrical insulation after curing, and the biological content is greater than 90%, the epoxy value reaches 0.28-0.51 eq / 100g, suitable for coatings, composites, casting, electronic and electrical materials, adhesives and corrosion-resistant agents and other fields.Chinese patent CN107556459A introduces a preparation method of a new type of biological epoxy resin containing pyridazinone structure, the resin has good thermal stability, and has broad application prospect in the fields of coatings, adhesives and aerospace.

[0007] World patent WO2016172353A, US2024301125A and US2009275674A all introduce biological epoxy resin that can be used in coatings. US patent US10745515B introduces a biological epoxy resin with excellent thermal properties and modulus.

[0008] Dimethyl succinyl succinate (DMSS) is an important intermediate for preparing dyes, fluorescent dyes and coating materials, which can be prepared from biologically derived succinic acid by esterification and Clasien ester condensation reaction, and contains one two C=O and ester group in its structure. A series of organic pigments containing quinacridone structure can be prepared from DMSS as raw material, and the structure of organic pigment is as follows:

[0009]

[0010] Chinese patents CN106831763A and CN105348127A introduce the synthesis of organic pigments containing quinacridone structure from DMSS as raw material; Chinese patent CN107200736A introduces a synthesis process of organic pigment 1 with good water solubility, surface activity and emulsifying and dispersing capacity; Chinese patent CN107057054A introduces the synthesis process of organic pigment 2.

[0011] Chinese patent CN101709034B introduces a synthesis process of bicyclo[2.2.2]octane 1,4-dicarboxylic acid monomethyl ester synthesized from DMSS as raw material, and its structure is as follows:

[0012]

[0013] Chinese patent CN101844996B introduces a series of intermediates of high organic pigments containing quinacridone structure, the structural formula is as follows:

[0014]

[0015] 2,5-dihydroxy terephthalic acid dimethyl ester (DDHT) is an intermediate of medicine, chemical synthesis and synthetic material, and its application field is wide. The compound can be obtained by bio-based succinic acid dimethyl succinate through aromatization (Polymer Chemistry.2018, 9:4113-4119), and its preparation route is as follows. Two phenolic hydroxyl groups exist in the structure of 2,5-dihydroxy terephthalic acid dimethyl ester, which can be used as the linking site of epichlorohydrin, and the compound has never been used as a synthetic epoxy resin monomer. Therefore, the present application aims to synthesize the corresponding epoxy resin monomer with 2,5-dihydroxy terephthalic acid dimethyl ester as raw material and to carry out curing.

[0016]

[0017] The present application is different from the bisphenol A type epoxy resin with potential physiological toxicity, and the compound with bisphenol structure is obtained by aromatization with bio-based succinic acid dimethyl succinate as raw material. The compound is prepared into an epoxy resin monomer, and a novel bio-based epoxy resin is obtained by curing. The resin has the characteristics of green, non-toxic and the like, and the raw material is cheap. SUMMARY

[0018] In order to find a substitute for bisphenol epoxy resin, the purpose of the present application is to provide a novel bio-based epoxy resin monomer containing 2,5-dihydroxy terephthalic acid dimethyl ester structure, which can be prepared from succinic acid dimethyl succinate, and has the advantages of low potential toxicity and low cost.

[0019] The present application provides a bio-based epoxy resin monomer containing 2,5-dihydroxy terephthalic acid dimethyl ester (DDHT-ECH), as shown in formula (I):

[0020]

[0021] The specific preparation method of the bio-based epoxy resin monomer of formula (I) prepared by the present application is: succinic acid dimethyl succinate and N-chlorosuccinimide (NCS) are subjected to aromatization reaction in acid as solvent, then the reaction liquid is cooled and cooled, and the solid is precipitated, and the solid is extracted by suction filtration, and then washed with acid, water and ether, and finally the product DDHT is obtained. DDHT is reacted with epichlorohydrin (ECH) under the action of a catalyst, the reaction liquid is cooled by ice bath, an alkaline aqueous solution is added dropwise, an organic solvent is used for extraction, and finally sand is passed through a column. The reaction equation is as follows:

[0022]

[0023] The acid is acetic acid.

[0024] The molar ratio of dimethyl succinyl succinate to NCS is 1:0.9-1:1.2, preferably 1:1.

[0025] The ether is diethyl ether, butyl ether, preferably diethyl ether.

[0026] The catalyst can be tetrabutylammonium bromide (TBAB), Na2CO3, K2CO3, preferably TBAB.

[0027] The molar ratio of dimethyl 2,5-dihydroxyterephthalate to tetrabutylammonium bromide is 1:0.8-1:1.2, preferably 1:1.

[0028] The molar ratio of dimethyl 2,5-dihydroxyterephthalate to epichlorohydrin is 1:4-1:12, preferably 1:10.

[0029] The basic solution can be an aqueous NaOH solution, an aqueous Na2CO3 solution, an aqueous K2CO3 solution, preferably an aqueous NaOH solution, with a concentration of 50wt%.

[0030] The extraction organic solvent can be dichloromethane, ethyl acetate, preferably dichloromethane.

[0031] The specific preparation method of the bio-based epoxy resin as formula (II) prepared in the application is as follows: (I) is weighed in a sample bottle, stirred and melted by heating. After (I) is melted, a curing agent is added. After the two are uniformly mixed, pour into a mold and put into a high-temperature oven for curing.

[0032]

[0033] Wherein, R is alkyl, polyether segment, aromatic group, alicyclic group, m, n are natural numbers.

[0034] The curing agent is dimeramine 1074 (Huntsman), polyetheramine D400 (Huntsman), pentanediamine (Kaiser), isophorone diamine (Allnex), 4,4'-diaminodiphenyl methane (Allnex), m-phenylenediamine (Allnex), p-phenylenediamine (Allnex).

[0035] The molar ratio of (I) to the curing agent is 1.8:1-2.2:1, preferably 2:1.

[0036] The curing temperature is 100-160℃, preferably the temperature is 120℃.

[0037] Beneficial effects:

[0038] (1) The raw material used in the present application is biologically derived dimethyl succinyl succinate, which has the advantages of being cheap and easy to obtain, green and non-toxic, and through aromatization and epoxidation reactions, a bio-based epoxy resin monomer with the structure of formula (I) is obtained.

[0039] (2) By curing the bio-based epoxy resin monomer with the structure of formula (I) with curing agents such as dicyclopamine 1074, pentanediamine, polyetheramine D400, isophorone diamine, and 4,4'-diaminobenzene, a bio-based epoxy resin with the structure of formula (II) can be prepared. The preparation process of the resin is simple, the reaction yield is high, and the structure of the bio-based epoxy resin with the structure of formula (II) is novel and has not been reported before. It is a bio-based, green and environmentally friendly product, which has the dual effects of saving petroleum resources and protecting the environment. It has important significance for promoting the sustainable development of the bio-based epoxy resin field. BRIEF DESCRIPTION OF DRAWINGS

[0040] The embodiments of the present application will be described in detail with reference to the accompanying drawings, in which

[0041] Figure 1 Example 2: Preparation of dimethyl 2,5-dihydroxyterephthalate (DDHT) 1 H NMR chart

[0042] Figure 2 Example 7: Preparation of bio-based epoxy resin monomer (DDHT-ECH) 1 H NMR chart

[0043] Figure 3 Example 17: IR chart of bio-based epoxy resin (dicyclopamine 1074 as curing agent)

[0044] Figure 4 Example 22: IR chart of bio-based epoxy resin (polyetheramine D400 as curing agent) DETAILED DESCRIPTION

[0045] The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0046] The nuclear magnetic resonance hydrogen spectrum involved in the examples is measured by a Bruker Ascend TM-400 nuclear magnetic resonance hydrogen spectrometer of Bruker Company, and the deuterated reagent used is deuterated chloroform (Chloroform-d); the infrared spectrum involved is measured by a Nicolet is10 Fourier transform infrared spectrometer of Thermo Fisher Scientific.

[0047] Example 1

[0048] Preparation of 2,5-dihydroxyterephthalic acid dimethyl ester (DDHT): A 250 mL flask was charged with succinic acid dimethyl ester (11.4 g, 0.05 mol, 1 eq.), N-chlorosuccinimide (6.0075 g, 0.045 mol, 0.9 eq) and acetic acid 50 mL. Stirring was carried out at 80 °C under argon for 1 h. After completion of the reaction, it was cooled to room temperature and the solid was allowed to settle. The solid was filtered under vacuum. The solid was washed with acetic acid, then with water and finally with diethyl ether. The solid was dried under vacuum to obtain a yellow solid.

[0049] Example 2

[0050] Preparation of 2,5-dihydroxyterephthalic acid dimethyl ester (DDHT): A 250 mL flask was charged with succinic acid dimethyl ester (11.4 g, 0.05 mol, 1 eq.), N-chlorosuccinimide (6.0075 g, 0.045 mol, 0.9 eq) and acetic acid 50 mL. Stirring was carried out at 80 °C under argon for 1 h. After completion of the reaction, it was cooled to room temperature and the solid was allowed to settle. The solid was filtered under vacuum. The solid was washed with acetic acid, then with water and finally with diethyl ether. The solid was dried under vacuum to obtain a yellow solid. 1 H NMR (400 MHz, Chloroform-d) δ 10.05 (s, 2H), 7.46 (s, 2H), 3.97 (s, 6H).

[0051] Example 3

[0052] Preparation of 2,5-dihydroxyterephthalic acid dimethyl ester (DDHT): A 250 mL flask was charged with succinic acid dimethyl ester (11.4 g, 0.05 mol, 1 eq.), N-chlorosuccinimide (6.0075 g, 0.045 mol, 0.9 eq) and acetic acid 50 mL. Stirring was carried out at 80 °C under argon for 1 h. After completion of the reaction, it was cooled to room temperature and the solid was allowed to settle. The solid was filtered under vacuum. The solid was washed with acetic acid, then with water and finally with diethyl ether. The solid was dried under vacuum to obtain a yellow solid.

[0053] Example 4

[0054] Preparation of 2,5-dihydroxyterephthalic acid dimethyl ester (DDHT): A 250 mL flask was charged with succinic acid dimethyl ester (11.4 g, 0.05 mol, 1 eq), N-chlorosuccinimide (6.675 g, 0.05 mol, 1 eq), and 50 mL of acetic acid. The reaction was stirred at 80 °C under argon for 1 h. After the reaction was completed, it was cooled to room temperature and the solid was allowed to precipitate. The solid was washed with acetic acid, then water, and finally diethyl ether. The solid was dried under vacuum to yield a yellow solid.

[0055] Example 5

[0056] Preparation of 2,5-dihydroxyterephthalic acid dimethyl ester (DDHT): A 250 mL flask was charged with succinic acid dimethyl ester (11.4 g, 0.05 mol, 1 eq), N-chlorosuccinimide (7.98 g, 0.05 mol, 1 eq), and 50 mL of acetic acid. The reaction was stirred at 80 °C under argon for 1 h. After the reaction was completed, it was cooled to room temperature and the solid was allowed to precipitate. The solid was washed with acetic acid, then water, and finally diethyl ether. The solid was dried under vacuum to yield a yellow solid.

[0057] Example 6

[0058] Preparation of bio-based epoxy monomer (DDHT-ECH): A 250 mL flask was charged with 2,5-dihydroxyterephthalic acid dimethyl ester (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (18.4 g, 0.2 mol, 4 eq), and tetrabutylammonium bromide (16.1 g, 0.05 mol, 1 eq). A reflux apparatus was set up and the reaction was stirred at 80 °C under reflux for 3 h. After the reaction was completed, the reaction was cooled to room temperature in an ice bath and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. The reaction was extracted with dichloromethane / water and the organic phase was collected and dried over anhydrous sodium sulfate. The dichloromethane was removed by rotary evaporation and the product was passed through a column to yield a white solid.

[0059] Example 7

[0060] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.5 mol, 10 eq), and tetrabutylammonium bromide (16.1 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the product was obtained as a white solid with a yield of 60%. 1 H NMR (400 MHz, Chloroform-d) δ 7.43 (s, 2H), 4.32 (dd, J = 11.1, 2.8 Hz, 2H), 4.05 (dd, J = 11.1, 5.1 Hz, 2H), 3.91 (s, 6H), 3.37 (ddt, J = 5.2, 4.0, 2.7 Hz, 2H), 2.94 - 2.83 (m, 4H).

[0061] Example 8

[0062] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.5 mol, 10 eq), and tetrabutylammonium bromide (16.1 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the product was obtained as a white solid with a yield of 60%.

[0063] Example 9

[0064] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.5 mol, 10 eq), and tetrabutylammonium bromide (12.88 g, 0.04 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the product was obtained as a white solid after column chromatography.

[0065] Example 10

[0066] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.5 mol, 10 eq), and tetrabutylammonium bromide (12.88 g, 0.04 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the product was obtained as a white solid after column chromatography.

[0067] Example 11

[0068] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.2 mol, 4 eq), and Na2CO3(5.3 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the product was obtained as a white solid after column chromatography.

[0069] Example 12

[0070] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL Erlenmeyer flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.2 mol, 4 eq), K2CO3(6.9 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the Erlenmeyer flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the column was prepared and white solid was obtained.

[0071] Example 13

[0072] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL Erlenmeyer flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.2 mol, 4 eq), K2CO3(6.9 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the Erlenmeyer flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the column was prepared and white solid was obtained.

[0073] Example 14

[0074] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL Erlenmeyer flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.5 mol, 10 eq), tetrabutylammonium bromide (16.1 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium carbonate (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the Erlenmeyer flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the column was prepared and white solid was obtained.

[0075] Example 15

[0076] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.5 mol, 10 eq), and tetrabutylammonium bromide (16.1 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and potassium carbonate (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. Extraction was performed using a dichloromethane / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the product was obtained as a white solid after column chromatography.

[0077] Example 16

[0078] Preparation of bio-based epoxy resin monomer (DDHT-ECH): A 250 mL flask was charged with dimethyl 2,5-dihydroxyterephthalate (DDHT) (11.3 g, 0.05 mol, 1 eq), epichlorohydrin (46 g, 0.5 mol, 10 eq), and tetrabutylammonium bromide (16.1 g, 0.05 mol, 1 eq). A reflux apparatus was set up and stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice bath, and sodium hydroxide (10 g, 0.25 mol, 5 eq) was dissolved in 20 mL of water and slowly added to the flask. Extraction was performed using an ethyl acetate / water system, and the organic phase was collected and dried over anhydrous sodium sulfate. Dichloromethane was removed by rotary evaporation, and the product was obtained as a white solid after column chromatography.

[0079] Example 17

[0080] Preparation of bio-based epoxy resin (dimer diamine 1074 as curing agent (Hexion)): A 20 mL sample bottle was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.2168 g, 0.0036 mol, 1.8 eq) and heated to 110 °C under vacuum until it was melted. Dimer diamine 1074 (0.54 g, 0.002 mol, 1 eq) was added to the sample bottle, and after mixing, it was poured into a mold and cured in a 120 °C oven.

[0081] Example 18

[0082] Preparation of bio-based epoxy resin (dimer diamine 1074 as curing agent (Huntsman)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum, after it was melted, dimer diamine 1074 (0.54 g, 0.002 mol, 1 eq) was added to the sample vial, after mixed well, it was poured into a mold, cured in a 120 °C oven.

[0083] Example 19

[0084] Preparation of bio-based epoxy resin (dimer diamine 1074 as curing agent (Huntsman)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum, after it was melted, dimer diamine 1074 (0.54 g, 0.002 mol, 1 eq) was added to the sample vial, after mixed well, it was poured into a mold, cured in a 120 °C oven.

[0085] Example 20

[0086] Preparation of bio-based epoxy resin (dimer diamine 1074 as curing agent (Huntsman)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum, after it was melted, dimer diamine 1074 (0.54 g, 0.002 mol, 1 eq) was added to the sample vial, after mixed well, it was poured into a mold, cured in a 100 °C oven.

[0087] Example 21

[0088] Preparation of bio-based epoxy resin (dimer diamine 1074 as curing agent (Huntsman)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum, after it was melted, dimer diamine 1074 (0.54 g, 0.002 mol, 1 eq) was added to the sample vial, after mixed well, it was poured into a mold, cured in a 160 °C oven.

[0089] Example 22

[0090] Preparation of bio-based epoxy resin (polyetheramine D400 as curing agent (Huntsman)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum. Once melted, polyetheramine D400 (0.8 g, 0.002 mol, 1 eq) was added to the sample vial and mixed until homogeneous. It was then poured into a mold and cured in a 120 °C oven.

[0091] Example 23

[0092] Preparation of bio-based epoxy resin (pentanediamine as curing agent (Kasei)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum. Once melted, pentanediamine (0.204 g, 0.002 mol, 1 eq) was added to the sample vial and mixed until homogeneous. It was then poured into a mold and cured in a 120 °C oven.

[0093] Example 24

[0094] Preparation of bio-based epoxy resin (isophorone diamine as curing agent (Allnex)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum. Once melted, isophorone diamine (0.34 g, 0.002 mol, 1 eq) was added to the sample vial and mixed until homogeneous. It was then poured into a mold and cured in a 120 °C oven.

[0095] Example 25

[0096] Preparation of bio-based epoxy resin (4,4’-diaminodiphenylmethane as curing agent (Allnex)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum. Once melted, 4,4’-diaminodiphenylmethane (0.396 g, 0.002 mol, 1 eq) was added to the sample vial and mixed until homogeneous. It was then poured into a mold and cured in a 120 °C oven.

[0097] Example 26

[0098] Preparation of bio-based epoxy resin (m-phenylenediamine as curing agent (Araldite)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum, once molten, m-phenylenediamine (0.216 g, 0.002 mol, 1 eq) was added to the sample vial and mixed until homogenous, it was then poured into a mould and cured in a 120 °C oven.

[0099] Example 27

[0100] Preparation of bio-based epoxy resin (p-phenylenediamine as curing agent (Araldite)): A 20 mL sample vial was charged with bio-based epoxy resin monomer (DDHT-ECH) (1.352 g, 0.004 mol, 2 eq) and heated to 110 °C under vacuum, once molten, p-phenylenediamine (0.216 g, 0.002 mol, 1 eq) was added to the sample vial and mixed until homogenous, it was then poured into a mould and cured in a 120 °C oven.

Claims

1. A bio-based epoxy resin monomer DDHT-ECH, characterized by having a structure as shown in formula (I): 。 2. The bio-based epoxy resin monomer of claim 1 having a structure as shown in formula (I) is prepared by reacting dimethyl 2,5-dihydroxyterephthalate with epichlorohydrin in the presence of a catalyst to obtain a bio-based epoxy resin monomer containing dimethyl 2,5-dihydroxyterephthalate, DDHT-ECH.

3. The bio-based epoxy resin monomer preparation method of claim 2, wherein the catalyst is tetrabutylammonium bromide.

4. The bio-based epoxy resin monomer preparation method of claim 2, wherein The molar ratio of dimethyl 2,5-dihydroxyterephthalate to epichlorohydrin is 1:4-1:

12.

5. The method for preparing a bio-based epoxy resin monomer according to claim 2, wherein: The molar ratio of dimethyl 2,5-dihydroxyterephthalate to tetrabutylammonium bromide is 1:0.8-1:1.

2.

6. A bio-based epoxy resin, characterized by having a structure as shown in formula (II): wherein R is an alkyl group, a polyether chain segment, an aromatic group, an alicyclic group, and m and n are natural numbers.

7. The bio-based epoxy resin of claim 6 having a structure as shown in formula (II) is prepared by heating and melting the bio-based epoxy resin monomer of claim 1, adding a curing agent, mixing uniformly, and then pouring into a mold to form.

8. The method for preparing a bio-based epoxy resin according to claim 7, wherein The molar ratio of the bio-based epoxy resin monomer containing dimethyl 2,5-dihydroxyterephthalate, DDHT-ECH, to the curing agent is 1.8:1-2.2:

1.

9. The method for preparing a bio-based epoxy resin according to claim 7, wherein: The curing agent is dimeramine 1074, polyetheramine D400, pentanediamine, isophorone diamine, 4,4'-diaminodiphenylmethane, m-phenylenediamine, or p-phenylenediamine.

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