A novel bio-based alicyclic epoxy resin and a preparation method thereof

Abstract

The application discloses a novel bio-based alicyclic epoxy resin and a preparation method thereof, and has the beneficial effects that the application provides a bio-based epoxy resin based on citral and a preparation method thereof, the bio-based epoxy resin has structures shown in formula (I) and (II), the structures are dendritic molecular structures, spatial free volumes are increased, the epoxy monomer has more epoxy groups, crosslinking density of the epoxy resin is improved, and the six-membered ring structure is also helpful to improvement of thermal stability and mechanical properties of the material; meanwhile, compared with existing epoxy resin materials, the application has the characteristics of green, non-toxic, good biocompatibility, a novel structure, simple synthesis process and high yield, etc.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin technology, specifically to a novel bio-based alicyclic epoxy resin and its preparation method. Background Technology

[0002] Currently, most epoxy resins are derived from petroleum resources, especially bisphenol A epoxy resins. Petroleum is a non-renewable resource, and its dwindling reserves inevitably lead to a continuous increase in the cost of polymer materials derived from petroleum. Furthermore, bisphenol A is suspected of physiological toxicity and its use has been restricted in many countries, including Europe. Therefore, given the current depletion of petroleum resources, there is an urgent need to use raw materials from other sources to produce epoxy resins and reduce dependence on petroleum. Finding sustainable, high-quality, inexpensive, and non-toxic petroleum substitutes is crucial for the existence and development of the polymer industry. Developing alternatives with renewable resources and comparable performance is particularly important. Vigorously developing bio-based renewable monomers has excellent development prospects and aligns with the green and sustainable development strategy of the polymer industry.

[0003] Bio-based epoxy resins use renewable resources as their main raw materials, which reduces the plastics industry's consumption of petrochemical products and also reduces the environmental pollution caused by the production of petroleum-based raw materials. It is an important development direction for polymer materials and has significant practical value and broad development prospects.

[0004] With the increasing awareness of environmental protection, bio-based materials have developed rapidly. Bio-based epoxy resins have replaced or even surpassed traditional commercial epoxy resins in terms of mechanical and thermal properties, and are gradually becoming a substitute for petroleum products. The development of bio-based epoxy resins has reduced the consumption of petroleum resources and reduced the impact on the environment. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems by designing a novel bio-based alicyclic epoxy resin and its preparation method.

[0006] The technical solution of the present invention to achieve the above objectives is a novel bio-based alicyclic epoxy resin, the structural formula of which is Formula I:

[0007]

[0008] A novel bio-based alicyclic epoxy resin, with the structural formula of Formula II:

[0009]

[0010] A novel method for preparing a bio-based alicyclic epoxy resin of formula (I) includes the following steps:

[0011] Step 1: Add solvent and catalyst A to the reactor and stir. Heat in an oil bath and control the internal temperature at 40-100℃. After the temperature reaches the required level, start adding citric acid dropwise, controlling the reaction temperature at 40-100℃. After the dropwise addition is completed, keep the temperature for 5-10 hours. Add alkaline solution to wash, separate the organic phase, and obtain product 1 after solvent removal.

[0012] Step 2: Add product 1 and solvent to the reactor, cool in an ice bath at 0-10℃, slowly add peroxide, control the reaction temperature at 15-40℃, keep warm for 4-12 hours, and then obtain the target product after post-processing.

[0013] A method for preparing a novel bio-based alicyclic epoxy resin (Formula II) includes the following steps:

[0014] Step 1: Add solvent, catalyst A and isopropanol to the reactor and stir. Heat in an oil bath and control the internal temperature at 50-120℃. After the temperature reaches the required level, start adding citric acid dropwise and control the reaction temperature at 50-100℃. After the dropwise addition is completed, keep the temperature for 5-15 hours. Add alkaline solution to wash and separate the organic phase. After solvent removal, product 2 is obtained.

[0015] Step 2: Add product 2, solvent, 3-cyclohexenecarboxylic acid and catalyst B to the reactor and stir. Heat in an oil bath and control the reaction temperature at 100-150℃. Reflux to separate water. After water separation, perform post-treatment to obtain product 3.

[0016] Step 3: Add product 3 and solvent to the reactor, cool in an ice bath at 0-10℃, slowly add peroxide, control the reaction temperature at 15-40℃, keep warm for 4-12 hours, and then obtain the target product after post-processing.

[0017] As a further supplement to this technical solution, catalyst A includes a metal catalyst, a basic catalyst, and aluminum isopropoxide.

[0018] As a further supplement to this technical solution, the molar ratio of catalyst A to citric acid in step one is 0.003-0.015:1, and the molar ratio of catalyst A to citric acid in step one is 0.02-0.05:1.

[0019] As a further supplement to this technical solution, the peroxide mentioned in step two is any one or a combination of peracetic acid, cumene hydroperoxide, and m-chloroperoxybenzoic acid.

[0020] As a further supplement to this technical solution, the catalyst B mentioned in step 2 includes any one or more of concentrated sulfuric acid, concentrated hydrochloric acid, p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, and thionyl chloride.

[0021] As a further supplement to this technical solution, the molar ratio of catalyst B to product 2 in step 2 is 0.02-0.05:1, and the molar ratio of 3-cyclohexenecarboxylic acid to citric acid in step 2 is 1-1.5:1.

[0022] As a further supplement to this technical solution, the molar ratio of the peroxide to the C=C bond is 1 to 2:1.

[0023] The beneficial effects are that this invention provides a bio-based epoxy resin based on citric acid aldehyde and its preparation method. The bio-based epoxy resin has the structure shown in formulas (I) and (II). This type of structure is a dendritic molecular structure, which increases the free volume in space. At the same time, the epoxy monomer has more epoxy groups, which improves the crosslinking density of the epoxy resin. The six-membered ring structure also helps to improve the thermal stability and mechanical properties of the material. In addition, compared with existing epoxy resin materials, this invention has the characteristics of being green and non-toxic, having good biocompatibility, a novel structure, a simple synthesis process, and a high yield. Attached Figure Description

[0024] Figure 1 It is the structural formula of Formula III;

[0025] Figure 2 It is the structural formula of formula IV;

[0026] Figure 3 This is the preparative structural formula of compound I;

[0027] Figure 4 This is the preparative structural formula for compound II;

[0028] Figure 5 This is the H-NMR spectrum of compound I of the present invention;

[0029] Figure 6 This is the H-NMR spectrum of compound II of the present invention. Detailed Implementation

[0030] To facilitate a clearer understanding of this technical solution by those skilled in the art, the technical solution of the present invention will be described in detail below with reference to embodiments:

[0031] A novel bio-based alicyclic epoxy resin, with the structural formula of Formula I:

[0032]

[0033] A novel bio-based alicyclic epoxy resin, with the structural formula of Formula II:

[0034]

[0035] A novel method for preparing a bio-based alicyclic epoxy resin of formula (I) includes the following steps:

[0036] Step 1: Add solvent and catalyst A to the reactor and stir. Heat in an oil bath and control the internal temperature at 40-100℃. After the temperature reaches the required level, start adding citric acid dropwise, controlling the reaction temperature at 40-100℃. After the dropwise addition is completed, keep the temperature for 5-10 hours. Add alkaline solution to wash, separate the organic phase, and obtain product 1 after solvent removal.

[0037] Step 2: Add product 1 and solvent to the reactor, cool in an ice bath at 0-10℃, slowly add peroxide, control the reaction temperature at 15-40℃, keep warm for 4-12 hours, and then obtain the target product after post-processing.

[0038] A method for preparing a novel bio-based alicyclic epoxy resin (Formula II) includes the following steps:

[0039] Step 1: Add solvent, catalyst A and isopropanol to the reactor and stir. Heat in an oil bath and control the internal temperature at 50-120℃. After the temperature reaches the required level, start adding citric acid dropwise and control the reaction temperature at 50-100℃. After the dropwise addition is completed, keep the temperature for 5-15 hours. Add alkaline solution to wash and separate the organic phase. After solvent removal, product 2 is obtained.

[0040] Step 2: Add product 2, solvent, 3-cyclohexenecarboxylic acid and catalyst B to the reactor and stir. Heat in an oil bath and control the reaction temperature at 100-150℃. Reflux to separate water. After water separation, perform post-treatment to obtain product 3.

[0041] Step 3: Add product 3 and solvent to the reactor, cool in an ice bath at 0-10℃, slowly add peroxide, control the reaction temperature at 15-40℃, keep warm for 4-12 hours, and then obtain the target product after post-processing.

[0042] Catalyst A includes metal catalysts such as silver, copper, platinum, and palladium, alkaline catalysts such as sodium hydroxide, sodium carbonate, and potassium hydroxide, and aluminum isopropoxide, etc.

[0043] In step one, the molar ratio of catalyst A to citric acid is 0.003-0.015:1, and the molar ratio of catalyst A to citric acid is 0.02-0.05:1.

[0044] The peroxides mentioned in step two include peracetic acid, cumene hydroperoxide, and m-chloroperoxybenzoic acid.

[0045] The catalyst B mentioned in step 2 includes concentrated sulfuric acid, concentrated hydrochloric acid, p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, thionyl chloride, etc.

[0046] In step 2, the molar ratio of catalyst B to product 2 is 0.02-0.05:1, and the molar ratio of 3-cyclohexenecarboxylic acid to citric acid is 1-1.5:1.

[0047] The molar ratio of the peroxide to the C=C bond is 1 to 2:1.

[0048] Example 1: The preparation method for the target product using formula (Ⅰ) is as follows:

[0049] Add 20g toluene and 1g aluminum isopropoxide to a 250ml dry three-necked round-bottom flask, heat in an oil bath at 60℃, and stir.

[0050] When the internal temperature reaches 55℃, 96.2g of citric acid is added dropwise, and the reaction temperature is maintained at 55-65℃. After the addition is completed, the reaction is kept at this temperature for 6 hours. After the temperature is maintained, the temperature of the reaction solution is lowered to room temperature, 180g of toluene is added, and 100g of 5% sodium carbonate aqueous solution is added for washing. The organic phase is separated, and after solvent removal, 95g of the ester shown in formula (Ⅲ) is obtained.

[0051] In a 1000ml dry three-necked round-bottom flask, add 95g of the ester shown in formula (Ⅲ), 285g of dichloroethane, 120g of acetic anhydride, 30g of sodium carbonate, and 0.12g of sodium polyphosphate. Cool the mixture to below 10℃ in an ice bath, then add 120g of 50% hydrogen peroxide dropwise. Control the reaction temperature at 20-25℃. After the addition is complete, keep the reaction at this temperature for 8 hours. After post-treatment, obtain 105.6g of the product shown in formula (Ⅰ).

[0052] The product was tested and found to have an EEW of 152.3 g / mol, with a yield of 94.8%.

[0053] Experimental Example 2: The preparation method for the target product using formula (II) is as follows:

[0054] 3g of aluminum isopropoxide and 92g of isopropanol were added to a 250ml dry three-necked round-bottom flask. The mixture was placed in an oil bath at 90℃ and stirred until the internal temperature reached 80℃. 96.2g of citric acid was then added dropwise. The reaction temperature was maintained at 85-95℃, and the reaction was continued at this temperature for 8 hours after the addition was complete. After the reaction was completed, the temperature was lowered to 50℃, and the isopropanol was removed under reduced pressure. After solvent removal, the mixture was filtered to obtain 92g of citric acid.

[0055] Add 92g of citric acid, 62.6g of 3-cyclohexenecarboxylic acid, 150g of toluene, and 1.1g of methanesulfonic acid to a 500ml dry three-necked round-bottom flask. Reflux the mixture in an oil bath at 120℃ to remove water. After the system stops discharging, continue to keep it at this temperature for 1 hour, then cool it to room temperature. Add 150g of 3% sodium carbonate for washing. After solvent removal from the organic phase, 140g of the ester shown in formula (Ⅳ) is obtained.

[0056] In a 1000ml dry three-necked round-bottom flask, 140g of the ester shown in formula (IV), 420g of dichloroethane, 168g of acetic anhydride, 19.6g of sodium carbonate, and 0.17g of sodium polyphosphate were added. The mixture was cooled to below 10℃ in an ice bath, and 168g of 50% hydrogen peroxide was added dropwise. The reaction temperature was controlled at 20-25℃. After the addition was completed, the reaction was maintained at this temperature for 10 hours. After post-processing, 155.6g of the product shown in formula (II) was obtained. The product was tested and found to have an EEW of 138.5g / mol, with a yield of 88.4%.

[0057] The cured product performance data of Compound I and Compound II are shown in Tables 1 and 2. Test data show that the photocuring rate of Compound I and Compound II is much slower than that of TTA21P, and the hardness of the cured products is also lower than that of TTA21P. However, Compound I and Compound II have better flexibility than TTA21P.

[0058] Table 1. Anhydride Curing Data

[0059]

[0060] Table 2 UV Curing Data

[0061]

[0062] The above technical solutions only embody the preferred technical solutions of the present invention. Any modifications that may be made by those skilled in the art to certain parts thereof embody the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A novel bio-based alicyclic epoxy resin, characterized in that, Its structural formula is Formula I: Equation (Ⅰ).

2. A novel bio-based alicyclic epoxy resin, characterized in that, Its structural formula is Formula II: Formula (II).

3. The method for preparing a novel bio-based alicyclic epoxy resin according to claim 1, characterized in that, Includes the following steps: Step 1: Add solvent and catalyst A aluminum isopropoxide to the reactor and stir. Heat in an oil bath and control the internal temperature at 40-100℃. After the temperature reaches the required level, start adding citric acid dropwise and control the reaction temperature at 40-100℃. After the dropwise addition is completed, keep the temperature for 5-10 hours. Add alkaline solution to wash and separate the organic phase. After solvent removal, product 1 is obtained as shown in formula (Ⅲ). Formula (Ⅲ); Step 2: Add product 1 and solvent to the reactor, cool in an ice bath at 0-10℃, slowly add peroxide, control the reaction temperature at 15-40℃, keep warm for 4-12 hours, and then obtain the target product after post-processing.

4. The method for preparing a novel bio-based alicyclic epoxy resin according to claim 2, characterized in that, Includes the following steps: Step 1: Add solvent, catalyst A aluminum isopropoxide, and isopropanol to the reactor and stir. Heat in an oil bath and control the internal temperature at 50-120℃. After the temperature reaches the required level, start adding hesperidin dropwise and control the reaction temperature at 50-100℃. After the dropwise addition is completed, keep the temperature for 5-15 hours. Add alkaline solution to wash and separate the organic phase. After solvent removal, product 2, namely hesperidin, is obtained. Step 2: Add product 2, solvent, 3-cyclohexenecarboxylic acid, and catalyst B methanesulfonic acid to the reactor and stir. Heat in an oil bath, controlling the reaction temperature at 100-150℃. Reflux to separate water. After water separation, perform post-treatment to obtain product 3 as shown in formula (Ⅳ). Formula (Ⅳ); Step 3: Add product 3 and solvent to the reactor, cool in an ice bath at 0-10℃, slowly add peroxide, control the reaction temperature at 15-40℃, keep warm for 4-12 hours, and then obtain the target product after post-processing.

5. The method for preparing a novel bio-based alicyclic epoxy resin according to claim 3, characterized in that, The molar ratio of catalyst A to citric acid aldehyde in step one is 0.003-0.015:

1.

6. The method for preparing a novel bio-based alicyclic epoxy resin according to claim 4, characterized in that, The molar ratio of catalyst A to citric acid in step 1 is 0.02-0.05:

1.

7. The method for preparing a novel bio-based alicyclic epoxy resin according to claim 3, characterized in that, The peroxide mentioned in step two is any one or a combination of peracetic acid, cumene hydroperoxide, and m-chloroperoxybenzoic acid.

8. The method for preparing a novel bio-based alicyclic epoxy resin according to claim 4, characterized in that, The molar ratio of catalyst B to product 2 in step 2 is 0.02-0.05:1, and the molar ratio of 3-cyclohexenecarboxylic acid to citric acid in step 2 is 1-1.5:

1.

9. A method for preparing a novel bio-based alicyclic epoxy resin according to claim 3 or 4, characterized in that, The molar ratio of the peroxide to the C=C bond is 1~2:1.

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