Alkynyl modified diethylstilbestrol benzoxazine monomer as well as preparation method and application thereof
The alkynyl-modified diethylstilbenebenzooxazine monomer was synthesized by the solvent-free method, which solved the problem of insufficient heat resistance of diethylstilbenebenzooxazine resin, and achieved the preparation of a high-performance resin, with excellent thermal stability and flame retardancy.
Patent Information
- Application Number
- CN202510364617.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-08-15
AI Technical Summary
The heat resistance of the benzoxazine resin based on diethylstilbet in the prior art is not ideal, and because it is difficult to dissolve in most organic solvents, it is insufficient in development and utilization.
The alkynyl-modified diethylstilbenebenzooxazine monomer was synthesized by solvent-free method. The benzooxazine monomer was prepared as a white solid by reacting diethylstilbene, 3-aminophenylacetylene and paraformaldehyde, and polymerized at high temperature to form a tight crosslinked structure.
It improves the thermal stability and flame retardancy of benzoxazine resin, has simple synthesis steps and short reaction time, which is suitable for large-scale production.
Smart Images
Figure CN120483932A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of resin synthesis, and particularly relates to an alkynyl-modified diethylstilbestrol-based benzoxazine monomer, a preparation method thereof, and an application thereof. Background Art
[0002] Benzoxazine resins are an emerging class of thermosetting resins. Compared to traditional thermosetting resins, benzoxazine resins exhibit superior thermal stability and flame retardancy. Furthermore, benzoxazine resins exhibit unique properties, such as zero cure shrinkage, low water absorption, and a high glass transition temperature. Their exceptional molecular design flexibility allows for the preparation of benzoxazine resins with specific functionalities by modifying the functional groups of component compounds, such as phenols and amines. This holds great promise for their broad application in a wide range of fields, including printed circuit boards, automotive manufacturing, and aerospace.
[0003] Diethylstilbestrol is an important nonsteroidal hormone with a unique structure containing a phenolic hydroxyl group and a central double bond, making it a promising phenolic source for the synthesis of high-performance thermosetting resins. However, due to its poor solubility in most organic solvents, only two diethylstilbestrol-based benzoxazines have been reported, and both exhibit suboptimal heat resistance. This suggests that diethylstilbestrol, as a promising phenolic source for thermosetting resins, has yet to be fully exploited. Summary of the Invention
[0004] Technical Problems to be Solved: In response to the above technical problems, the main purpose of the present invention is to develop a new method (solvent-free method) to synthesize high-performance benzoxazine based on diethylstilbestrol; by introducing alkynyl modification to increase the crosslinking density of benzoxazine resin, further improving its thermal stability and flame retardancy.
[0005] Technical solution: An alkynyl-modified diethylstilbestrol-based benzoxazine monomer, the structural formula of which is as follows: .
[0006] The preparation method of the benzoxazine monomer is as follows: diethylstilbestrol, 3-aminophenylacetylene and paraformaldehyde are mixed, and the mixture is heated to reflux, cooled, extracted with dichloromethane, evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid benzoxazine monomer.
[0007] Preferably, the molar ratio of diethylstilbestrol, 3-aminophenylacetylene and paraformaldehyde is 1:(2-2.5):(4-6).
[0008] Preferably, the molar ratio of diethylstilbestrol, 3-aminophenylacetylene and paraformaldehyde is 1:2.5:6.
[0009] Preferably, the heating reflux temperature is 100-120°C.
[0010] Preferably, the heating reflux duration is 2 to 4 hours.
[0011] Application of the above benzoxazine monomer in the preparation of polybenzoxazine resin.
[0012] Preferably, the application is: heating the benzoxazine monomer at 140° C. for 2 h, 160° C. for 2 h, 180° C. for 2 h, 200° C. for 2 h, and 220° C. for 2 h to obtain a cured polybenzoxazine resin.
[0013] The polybenzoxazine resin is prepared by the above application.
[0014] Beneficial effects: The present invention uses diethylstilbestrol, 3-aminophenylacetylene and paraformaldehyde to synthesize a novel acetylenic-modified bifunctional benzoxazine monomer through a solvent-free method, and high-temperature polymerization forms a tightly cross-linked structure, so that the benzoxazine resin has extremely outstanding thermal stability and flame retardancy. The synthesis steps are simple, the reaction time is short, the yield is high, and it is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of the benzoxazine monomer of Example 1 of the present invention; Figure 2 is the infrared spectrum of the benzoxazine monomer of Example 1 of the present invention; Figure 3 is a DSC curve diagram of the benzoxazine monomer of Example 1 of the present invention; Figure 4 This is a diagram of a polybenzoxazine resin sample according to Example 9 of the present invention; Figure 5 is an infrared spectrum of the polybenzoxazine of Example 9 of the present invention; Figure 6 is a TGA curve of polybenzoxazine in Example 10 of the present invention. DETAILED DESCRIPTION
[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Example 1
[0017] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.9287 g, 25 mmol), and paraformaldehyde (1.8000 g, 60 mmol) were added to a 100 ml three-necked flask and stirred to mix thoroughly at room temperature. The mixture was heated to reflux at 120°C for 3 h and monitored by thin-layer chromatography. The reaction was completed when the reaction system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 96%.
[0018] The product's H NMR spectrum, IR spectrum, and DSC curve are shown in Figure 2. Figure 1 、 Figure 2 、 Figure 3 shown.
[0019] Figure 1 This is a hydrogen nuclear magnetic resonance spectrum. As can be seen from the figure, the chemical shifts of around 4.71 ppm and 5.49 ppm are characteristic peaks of the methylene group on the oxazine ring, and the chemical shift of 4.14 ppm is a characteristic peak of the alkynyl hydrogen. Figure 2 It is an infrared spectrum. As can be seen from the figure, 946cm -1 and 1230cm -1 The characteristic absorption peak of benzoxazine ring is at 3278 cm -1 The sharp peak is the alkynyl absorption peak.
[0020] The structural characteristics of the alkynyl-modified benzoxazine monomer can be basically determined by the nuclear magnetic resonance hydrogen spectrum and the infrared spectrum.
[0021] Figure 3 2 is a DSC curve diagram, from which it can be seen that the peak temperature of the exothermic curing of benzoxazine monomer is 228°C. Example 2
[0022] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.3430 g, 20 mmol), and paraformaldehyde (1.8000 g, 60 mmol) were added to a 100 ml three-necked flask and stirred to mix thoroughly at room temperature. The mixture was heated to reflux at 120°C for 3 h and monitored by thin-layer chromatography. The reaction was complete when the system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 90%. Example 3
[0023] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.3430 g, 20 mmol), and paraformaldehyde (1.5000 g, 50 mmol) were added to a 100 ml three-necked flask and stirred to mix thoroughly at room temperature. The mixture was heated to reflux at 120°C for 3 h and monitored by thin-layer chromatography. The reaction was completed when the reaction system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 86%. Example 4
[0024] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.3430 g, 20 mmol), and paraformaldehyde (1.5000 g, 40 mmol) were added to a 100 ml three-necked flask and stirred to mix thoroughly at room temperature. The mixture was heated to reflux at 120°C for 3 h and monitored by thin-layer chromatography. The reaction was complete when the system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 80%. Example 5
[0025] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.9287 g, 25 mmol), and paraformaldehyde (1.2000 g, 40 mmol) were added to a 100 ml three-necked flask and stirred at room temperature to mix thoroughly. The mixture was heated to reflux at 120°C for 3 h and monitored by thin-layer chromatography. The reaction was completed when the reaction system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 78%. Example 6
[0026] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.9287 g, 25 mmol), and paraformaldehyde (1.8000 g, 60 mmol) were added to a 100 ml three-necked flask and stirred to mix thoroughly at room temperature. The mixture was heated to reflux at 100°C for 3 h and monitored by thin-layer chromatography. The reaction was completed when the reaction system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 85%. Example 7
[0027] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.9287 g, 25 mmol), and paraformaldehyde (1.8000 g, 60 mmol) were added to a 100 ml three-necked flask and stirred to mix thoroughly at room temperature. The mixture was heated to reflux at 110°C for 3 h and monitored by thin-layer chromatography. The reaction was completed when the reaction system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 90%. Example 8
[0028] Diethylstilbestrol (2.6835 g, 10 mmol), 3-aminophenylacetylene (2.9287 g, 25 mmol), and paraformaldehyde (1.8000 g, 60 mmol) were added to a 100 ml three-necked flask and stirred to mix thoroughly at room temperature. The mixture was heated to reflux at 120°C for 4 h and monitored by thin-layer chromatography. The reaction was complete when the system gradually turned dark and viscous. The mixture was cooled to room temperature and extracted with dichloromethane. The solvent was evaporated under reduced pressure and recrystallized from ethanol to obtain a white solid with a yield of 92%. Example 9
[0029] The benzoxazine monomer prepared in Example 1 was poured into a mold and heated at 140° C. for 2 h, 160° C. for 2 h, 180° C. for 2 h, 200° C. for 2 h, and 220° C. for 2 h to obtain a cured polybenzoxazine resin.
[0030] The sample picture and infrared spectrum of polybenzoxazine are as follows Figure 4 and Figure 5 shown.
[0031] Figure 4 This is a picture of the benzoxazine resin sample prepared after curing; Figure 5 It is an infrared spectrum. As can be seen from the figure, 946cm -1 and 1230cm -1 The characteristic absorption peak of the benzoxazine ring at 3600-3200 cm -1 The hydroxyl absorption peak at 3278 cm-1 was significantly enhanced, indicating that benzoxazine was completely ring-opening polymerized; -1 The absorption peak of the alkynyl group disappears, 1600 cm -1 The broad peaks on the left and right are characteristic absorption peaks of the aromatic ring structure, indicating that the alkynyl moiety acts as an additional cross-linking site to trimerize into a benzene ring structure at high temperature. Example 10
[0032] The polybenzoxazine resin prepared in Example 9 was subjected to a thermogravimetric test.
[0033] Figure 6 This is the TGA curve of polybenzoxazine resin.
[0034] As can be seen from the figure, the temperature at which the polybenzoxazine resin loses 5% of its weight is 462°C, the temperature at which it loses 10% of its weight is 520°C, and the residual carbon rate is as high as 72% at 800°C.
Claims
1. An acetylenic-modified diethylstilbestrol-based benzoxazine monomer, characterized in that: Its structural formula is as follows: 。 2. The method for preparing the benzoxazine monomer according to claim 1, wherein: The method comprises the following steps: mixing diethylstilbestrol, 3-aminophenylacetylene and paraformaldehyde, heating and refluxing, cooling, extracting with dichloromethane, evaporating under reduced pressure and recrystallizing with ethanol to obtain a white solid benzoxazine monomer.
3. The method for preparing a benzoxazine monomer according to claim 2, wherein: The molar ratio of diethylstilbestrol, 3-aminophenylacetylene and paraformaldehyde is 1: (2-2.5): (4-6).
4. The method for preparing a benzoxazine monomer according to claim 2, wherein: The molar ratio of diethylstilbestrol, 3-aminophenylacetylene and paraformaldehyde is 1:2.5:
6.
5. The method for preparing a benzoxazine monomer according to claim 2, wherein: The heating reflux temperature is 100-120°C.
6. The method for preparing a benzoxazine monomer according to claim 2, wherein: The heating reflux duration is 2 to 4 hours.
7. Use of the benzoxazine monomer according to claim 1 in the preparation of polybenzoxazine resin.
8. The use according to claim 7, characterized in that The application is: heating the benzoxazine monomer at 140° C. for 2 hours, 160° C. for 2 hours, 180° C. for 2 hours, 200° C. for 2 hours, and 220° C. for 2 hours to obtain a cured polybenzoxazine resin.
9. The polybenzoxazine resin obtained by the application according to claim 7 or 8.