CN115073710A - Vanillyl epoxy resin and preparation method thereof - Google Patents

Abstract

The invention provides a degradable and recyclable bio-based epoxy resin based on vanillin and a preparation method thereof, belonging to the technical field of epoxy resin. The vanillin-based epoxy resin is prepared by firstly reacting 4-aminocyclohexanol with vanillin, mixing the prepared compound with epoxy chloropropane, stirring, adding a phase transfer catalyst, dropwise adding a NaOH solution, continuously reacting and standing, extracting an oil phase, and finally carrying out aftertreatment. The prepared epoxy resin contains a dynamic bond with a Schiff base structure, so that the epoxy resin has the advantages of degradability and recoverability. Meanwhile, the epoxy resin has higher crosslinking density, excellent thermal stability and mechanical property. The vanillin-based epoxy resin prepared by the invention is mainly derived from a bio-based monomer, has low cost and excellent performance, and has potential application value in the fields of industry, construction industry, daily life and the like.

Description

A kind of vanillin-based epoxy resin and preparation method thereof

technical field

The application relates to a degradable and recyclable vanillin-based epoxy resin and a preparation method thereof, belonging to the technical field of epoxy resins.

Background technique

As the most common thermosetting resin, epoxy resin has excellent thermodynamic properties and is widely used in adhesives, coatings, electronic device packaging, aerospace and other fields. However, most epoxy resins belong to petroleum resources, and bisphenol A series epoxy resins account for more than 90%. Since the discarded epoxy resins are not degradable, they cause great pollution to the environment. At the same time, studies have shown that bisphenol A epoxy resin can seriously interfere with the endocrine function of the human body. Many countries have banned the use of bisphenol A epoxy resin in food packaging related products. Therefore, the development of bio-derived and degradable epoxy resins is extremely important.

The bio-based epoxy resin synthesis substrates currently developed mainly include: vegetable oil, rosin, lignin derivatives, etc. The epoxy resin based on vegetable oil is mainly epoxidized soybean oil. Epoxidized soybean oil can be produced on a large scale, but because it contains more aliphatic chains, the thermodynamic properties of epoxy resins are poor. The epoxy resin prepared with rosin as the matrix contains hydrogen phenanthrene rings and has more rigid structures, resulting in poor resin toughness. Vanillin, as a lignin derivative, can be commercialized by extracting vanillin with low price. By designing its structure and introducing dynamic bonds, the preparation of bio-based degradable epoxy resin can be realized.

SUMMARY OF THE INVENTION

In view of the above problems existing in the prior art, the applicant of the present invention provides a degradable and recyclable vanillin-based epoxy resin and a preparation method thereof.

The present invention uses 4-aminocyclohexanol to chemically modify vanillin from green sources, synthesize a Schiff base structure with dynamic reversible bonds, and then reacts with epichlorohydrin to prepare a biodegradable epoxy resin, The prepared epoxy resin has excellent mechanical properties and combines the advantages of degradability and recyclability.

A kind of vanillin-based epoxy resin, its structure is as follows:

The preparation method of described vanillin-based epoxy resin, comprises the steps:

(1) Dissolve vanillin and 4-aminocyclohexanol in a solvent in proportion, react at 50-80°C for 1.5-2h under stirring, rinse the obtained compound for 3-5 times, and then place at 50-60°C Dry to obtain product 1;

(2) Mix the product 1 with epichlorohydrin, add a phase transfer catalyst, react at 110-130°C for 12-24h, then cool to 0-15°C, add NaOH solution dropwise, continue the reaction for 0.5-1h, let stand Then, the oil phase is extracted with an extractant, and the vanillin-based epoxy resin can be prepared after post-treatment.

In the step (1), the molar ratio of vanillin and 4-aminocyclohexanol is 1:1-1.5.

The solvent in the step (1) is methanol, ethanol, isopropanol, and acetone; the rinsing is a routine operation in the field, such as 3-5 times of rinsing with absolute ethanol.

The phase transfer catalyst in the step (2) is selected from tetrabutylammonium bromide, benzyltriethylammonium chloride, tetrabutylammonium hydrogen sulfate, trisixylmethylammonium chloride, dodecyl triethylammonium chloride. Any one or more of methyl ammonium chloride, tetradecyl trimethyl ammonium chloride, etc., the molar ratio of product 1 to phase transfer catalyst is 1:0.025-0.1; the molar ratio of product 1 to epichlorohydrin The ratio is 1:8-20; the extractant in the step (2) is one or more of dichloromethane, chloroform and ethyl acetate; the post-processing is conventional post-processing in the art.

In addition, the invention also includes the application of a vanillin-based epoxy resin, which is mainly used in the fields of adhesives, coatings, electronic device packaging, aerospace and the like.

The vanillin-based epoxy resin prepared by the present invention has the following characteristics: (1) the operation is simple and the conditions are mild, which is favorable for industrial production; (2) the bio-based degradable epoxy resin obtained by the present invention is convenient to cure, and can be cast by means of pouring shape, broaden the application field, and improve the practicability; (3) the bio-based degradable epoxy resin obtained by the present invention introduces reversible dynamic bonds, so that the cured network structure can be rapidly cracked under acidic conditions; (4) The bio-based degradable epoxy resin obtained by the present invention can be recovered by means of high temperature and high pressure, and the recovery efficiency is high.

Description of drawings

Fig. 1 is the hydrogen nuclear magnetic resonance spectrogram of the epoxy resin prepared by the present invention.

FIG. 2 is a tensile curve diagram showing the comparison of the mechanical properties of the epoxy resin prepared by the present invention and the commercially available bisphenol A epoxy resin.

Figure 3 is a graph showing the rapid degradation of the epoxy resin prepared by the present invention and the commercially available bisphenol A epoxy resin.

Fig. 4 is the tensile curve diagram (same as above) comparing the mechanical properties of the recovered epoxy resin prepared by the present invention with that of the original resin.

Detailed ways

The present invention will be described in further detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

Example 1

Step (1) 45.6g (0.3mol) vanillin and 34.5g (0.3mol) 4-aminocyclohexanol in 200ml ethanol.

The mixture was heated and kept at 50°C, mechanically stirred at 200 rpm, and the stirring time was 2h. Then, the temperature was lowered to 40° C., solid-liquid separation was performed, and the lower solid was collected, rinsed with absolute ethanol three times, and then dried in a 50° C. oven to obtain product 1.

Step (2) Add 24.9 g (0.1 mol) of product 1 into a 500 ml three-necked flask, then add 92.5 g (1 mol) of epichlorohydrin and 1.6 g of tetrabutylammonium bromide, and keep the temperature at 130°C. Mechanical stirring for 12h, 300 rev/min. Then the temperature was lowered to 0° C., 50 g of potassium hydroxide aqueous solution (50 wt %) was added, and mechanical stirring was continued for 1 h at 300 rpm. Then add 200 ml of dichloromethane, stir for 1 min at 300 rpm, remove the oily liquid in the lower layer, and wash with deionized water 3 times. Then add 30 g of anhydrous magnesium sulfate, stir and stand for 5 minutes, carry out solid-liquid separation, take the upper layer liquid, and then distill under reduced pressure to obtain bio-based degradable epoxy resin 1.

Example 2

Step (1) 45.6 g (0.3 mol) of vanillin and 37.9 g (0.33 mol) of 4-aminocyclohexanol were dissolved in 200 ml of ethanol. The mixture was heated and kept at 80°C, mechanically stirred at 200 rpm, and the stirring time was 1.5h. Then, the temperature was lowered to 40° C., solid-liquid separation was performed, and the lower solid was collected, rinsed with absolute ethanol three times, and then dried in a 50° C. oven.

Step (2) 24.9g (0.1mol) of the product obtained in step (1) was added to a 500ml three-necked flask, and then 92.5g (1mol) of epichlorohydrin and 3.2g of tetrabutylammonium bromide were added, and the temperature was kept at 130°C. Mechanical stirring for 12h, 300 rev/min. Then the temperature was lowered to 0° C., 50 g of potassium hydroxide aqueous solution (50 wt %) was added, and mechanical stirring was continued for 1 h at 300 rpm. Then add 200 ml of dichloromethane, stir for 1 min at 300 rpm, remove the oily liquid in the lower layer, and wash with deionized water 3 times. Then add 30 g of anhydrous magnesium sulfate, stir and let stand for 5 minutes, carry out solid-liquid separation, take the upper layer liquid, and then distill under reduced pressure to obtain bio-based degradable epoxy resin 2.

Example 3

Step (1) 45.6 g (0.3 mol) of vanillin and 51.7 g (0.45 mol) of 4-aminocyclohexanol were dissolved in 200 ml of ethanol. The mixture was heated and kept at 50°C, mechanically stirred at 200 rpm, and the stirring time was 2h. Then the temperature was lowered to 40°C, solid-liquid separation was performed, the lower solid was collected, rinsed with absolute ethanol three times, and then dried in a 60°C oven.

Step (2) 24.9g (0.1mol) of the product obtained in step (1) was added to a 500ml three-necked flask, and then 185g (2mol) of epichlorohydrin and 2g of tetrabutylammonium hydrogen sulfate were added, and the temperature was kept at 110°C. Mechanical stirring for 24h, 300 rev/min. Then the temperature was lowered to 0° C., 50 g of potassium hydroxide aqueous solution (50 wt %) was added, and mechanical stirring was continued for 1 h at 300 rpm. Then add 200 ml of dichloromethane, stir for 1 min at 300 rpm, remove the oily liquid in the lower layer, and wash with deionized water 3 times. Then add 30 g of anhydrous magnesium sulfate, stir and let stand for 5 minutes, carry out solid-liquid separation, take the upper layer liquid, and then distill under reduced pressure to obtain bio-based degradable epoxy resin 3.

Example 4

Step (1) 45.6 g (0.3 mol) of vanillin and 34.5 g (0.3 mol) of 4-aminocyclohexanol were dissolved in 200 ml of ethanol. The mixture was heated and kept at 50°C, mechanically stirred at 200 rpm, and the stirring time was 2h. Then, the temperature was lowered to 40° C., solid-liquid separation was performed, and the lower solid was collected, rinsed with absolute ethanol three times, and then dried in a 50° C. oven.

Step (2) Add 24.9 g (0.1 mol) of the product obtained in step (1) into a 500 ml three-necked flask, then add 185 g (2 mol) of epichlorohydrin and 2.4 g of benzyltriethylammonium chloride, and keep the temperature at 130°C. Mechanical stirring for 12h, 300 rev/min. Then the temperature was lowered to 15° C., 50 g of potassium hydroxide aqueous solution (50 wt %) was added, and mechanical stirring was continued for 1 h at 300 rpm. Then add 300 ml of ethyl acetate, stir for 1 min at 300 rpm, remove the oily liquid from the lower layer, and wash with deionized water 3 times. Then add 30 g of anhydrous magnesium sulfate, stir and let stand for 5 minutes, carry out solid-liquid separation, take the upper layer liquid, and then distill under reduced pressure to obtain bio-based degradable epoxy resin 4.

Example 5

Step (1) 45.6 g (0.3 mol) of vanillin and 34.5 g (0.3 mol) of 4-aminocyclohexanol were dissolved in 200 ml of ethanol. The mixture was heated and kept at 50°C, mechanically stirred at 200 rpm, and the stirring time was 2h. Then, the temperature was lowered to 40° C., solid-liquid separation was performed, and the lower solid was collected, rinsed with absolute ethanol three times, and then dried in a 50° C. oven.

Step (2) Add 24.9 g (0.1 mol) of the product obtained in step (1) into a 500 ml three-necked flask, then add 92.5 g (1 mol) of epichlorohydrin and 1.6 g of tetrabutylammonium bromide, and keep the temperature at 130°C. Mechanical stirring for 12h, 300 rev/min. Then the temperature was lowered to 0° C., 50 g of potassium hydroxide aqueous solution (50 wt %) was added, and mechanical stirring was continued for 1 h at 300 rpm. 500 ml of deionized water was added, the lower oily liquid was collected, and washed with water for three times, and the liquid was separated to obtain a yellow liquid. The yellow liquid was dissolved in 300 ml of acetone and precipitated in n-hexane, and the lower liquid was collected. Then add 50 g of anhydrous magnesium sulfate, stir and stand for 5 min, carry out solid-liquid separation, take the upper layer liquid, and then distill under reduced pressure to obtain yellow bio-based degradable epoxy resin 5.

Effect example 1

The room temperature tensile properties of the epoxy resin of Example 1 of the present invention and commercially available bisphenol A (Beijing Inokay Technology Co., Ltd.) were tested on a 5967X universal testing machine, and the size of the epoxy resin was 30 mm (length) and 5 mm (width). ) 2mm (thickness), and the stretching rate is 10mm/min.

Effect example 2

The rapid degradation diagram of the epoxy resin prepared in Example 2 of the present invention and the commercially available bisphenol A epoxy resin, the first row on the list is the epoxy resin of the present invention (the solvent is 0.1 mol/L hydrochloric acid and acetone, 1 ratio 1 mixed solution).

Effect example 3

The tensile curve of the recovered epoxy resin prepared in Example 3 of the present invention compared with the mechanical properties of the original epoxy resin, the epoxy resin size is 30mm (length) 5mm (width) 2mm (thickness), and the stretching rate is 10mm /min.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited thereto, and any form of evolution and improvement based on the inventive concept of the present invention fall within the protection scope of the present invention.

Claims (9)

1. a vanillin-based epoxy resin, characterized in that: the structure of the epoxy resin is as shown in formula (1)

2. vanillin-based epoxy resin preparation method according to claim 1, is characterized in that: described method comprises the steps: (1) Dissolve vanillin and 4-aminocyclohexanol in a solvent in proportion, react at 50-80°C for 1.5-2h under stirring, rinse the obtained compound for 3-5 times, and then place at 50-60°C Dry to obtain product 1; (2) Mix the product 1 with epichlorohydrin, add a phase transfer catalyst, react at 110-130°C for 12-24h, then cool to 0-15°C, add NaOH solution dropwise, continue the reaction for 0.5-1h, let stand Then, the oil phase is extracted with an extractant, and the vanillin-based epoxy resin can be prepared after post-treatment. 3. The vanillin-based epoxy resin preparation method according to claim 2, wherein the molar ratio of vanillin and 4-aminocyclohexanol in the step (1) is 1:1-1.5. 4. The method for preparing vanillin-based epoxy resin according to claim 2, wherein the solvent in the step (1) is methanol, ethanol, isopropanol and acetone. 5 . The method for preparing vanillin-based epoxy resin according to claim 2 , wherein the molar ratio of the product 1 to the phase transfer catalyst in the step (2) is 1:0.025-0.1. 6 . 6 . The method for preparing vanillin-based epoxy resin according to claim 2 , wherein the mol ratio of product 1 to epichlorohydrin in the step (2) is 1:8-20. 7 . 7. The method for preparing vanillin-based epoxy resin according to claim 2, wherein the phase transfer catalyst described in the step (2) is selected from benzyl triethyl ammonium chloride, tetrabutyl bromide Ammonium, tetrabutylammonium hydrogen sulfate, trisylmethyl ammonium chloride, dodecyl trimethyl ammonium chloride, tetradecyl trimethyl ammonium chloride any one or more of them, product 1 and The molar ratio of the phase transfer catalyst is 1:0.025-0.1. 8. vanillin-based epoxy resin preparation method according to claim 2, is characterized in that, the extraction agent in described step (2) is one or several in methylene dichloride, chloroform, ethyl acetate kind. 9 . The application of the vanillin-based epoxy resin according to claim 1 , wherein the epoxy resin is used in the fields of adhesives, coatings, electronic device encapsulation and aerospace. 10 .

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