Preparation method of (4)-4-aminophenoxy-2, 5-di-tert-butyl aniline monomer

Abstract

The invention discloses a preparation method of a (4)-4-aminophenoxy-2, 5-di-tert-butyl aniline monomer, which comprises the following steps: connecting benzene rings containing di-tert-butyl through an ether bond, and introducing the benzene rings into polyimide in the form of a diamine monomer; and the main chain structure of the polymer is twisted at a large angle by introducing tert-butyl, and polyimide is constructed in a manner of damaging inter-molecular coplane by flexible ether bonds, so that the purpose of increasing the free volume is achieved, the dielectric constant of the polyimide film is reduced, and the insulativity of the polyimide film is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic dielectric insulating layer materials, and particularly relates to a preparation method of (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer. Background Art

[0002] Today, with the rise of 5G communication, as the size of electronic devices becomes smaller and smaller, the distance between wires is gradually reduced. In the case of high wiring density and the number of metal wire layers, it is very important to reduce the metal wire diameter and the spacing between wires. However, when the wire spacing is reduced to a certain extent, it will cause the metal resistance, crosstalk between wires, and interlayer parasitic capacitance to become larger and larger, which has gradually become a bottleneck in the microelectronics industry. Therefore, interlayer insulating dielectric layer materials with lower dielectric constants suitable for high-density, high-frequency, and high-speed integrated circuit applications are becoming the research and development focus of this industry.

[0003] Among them, the structural design, development, and application of new diamine monomers used to prepare the above materials have become an important means to further reduce delay, power consumption, and improve the performance of integrated circuits. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a tert-butyl-containing diamine monomer. The tert-butyl-containing diamine monomer has a large free volume and low steric hindrance. By using it to prepare an interlayer insulating dielectric layer polyimide material, the dielectric constant is reduced and the dielectric loss is decreased, thereby solving problems such as signal delay and power loss caused by high-density integration.

[0005] To achieve the above purpose, the present invention provides a preparation method of (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer, including:

[0006] Preparing 2,5-di-tert-butyl-4-nitrophenol;

[0007] According to the reaction of 2,5-di-tert-butyl-4-nitrophenol and p-chloronitrobenzene, preparing (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene;

[0008] According to the reaction of (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene and ammonium formate ethanol solution, preparing (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer.

[0009] The present invention also provides a (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer.

[0010] The present invention also provides an application of a (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer.

[0011] Technical Effects and Advantages of the Present Invention

[0012] In the present invention, the benzene ring containing di-tert-butyl is connected through an ether bond and introduced into the polyimide in the form of a diamine monomer; then, by introducing tert-butyl, the main chain structure of the polymer is twisted at a large angle, and the flexible ether bond is used to disrupt the intermolecular coplanarity to construct the polyimide, achieving the purpose of increasing the free volume, reducing the dielectric constant of the polyimide film, and improving its insulation property.

[0013] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification and the drawings. Brief Description of the Drawings

[0014] Figure 1 1H NMR spectrum of (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer 1 ;

[0015] Figure 2 13C NMR spectrum of (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer 13 ;

[0016] Figure 3 Infrared spectrum of pyromellitic dianhydride-based polyimide film;

[0017] Figure 4 TGA curve of pyromellitic dianhydride-based polyimide;

[0018] Figure 5 SEM image of pyromellitic dianhydride-based polyimide;

[0019] Figure 6 Mechanical property curve of pyromellitic dianhydride-based polyimide;

[0020] Figure 7 Dielectric property curve of pyromellitic dianhydride-based polyimide film. Detailed Description of the Embodiments

[0021] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings provided by the present invention. Moreover, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0022] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of clear narration and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0023] The present invention provides a preparation method of (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer, which specifically includes:

[0024] 1. Prepare 2,5-di-tert-butyl-4-nitrophenol.

[0025] Specifically: Under the protection of nitrogen, add tert-butanol, phosphoric acid, and toluene with a molar ratio of 1:1 to 2:5 to 10 to the reactor; after cooling to 0 °C, dropwise add a toluene solution of nitrophenol (the mass ratio of nitrophenol to toluene is 1:10 to 15), heat to reflux for 12 to 72 h, add a saturated sodium chloride ice aqueous solution, filter to obtain a solid, and recrystallize the solid 3 times with methanol to obtain white 2,5-di-tert-butyl-4-nitrophenol powder, and the yield is about 80 to 90%.

[0026] 2. React 2,5-di-tert-butyl-4-nitrophenol with p-chloronitrobenzene to prepare (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene.

[0027] Specifically: Under the protection of nitrogen, add p-chloronitrobenzene, potassium carbonate, and anhydrous methanol to the reactor; after cooling to 0 °C, add 2,5-di-tert-butyl-4-nitrophenol to react. The solid content in the reaction system is 10 to 20%. After heating to reflux for 24 to 72 h, add a saturated sodium chloride ice aqueous solution, filter to obtain a solid, and recrystallize the solid 3 times with methanol to obtain yellow (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene crystals, and the yield is 80 to 85%.

[0028] 3. React (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene with a formic acid ammonium ethanol solution to prepare (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer.

[0029] Specifically: (4)-4-Nitrophenoxy-2,5-di-tert-butylnitrobenzene and palladium-carbon catalyst (Pd / C) were added to 1,4-dioxane or ethanol or N,N-dimethylformamide (DMF) at a mass ratio of 3-8:1, and the solid content of the reaction system was 10-20%; under nitrogen protection, heated to reflux, and a 25wt% ammonium formate ethanol solution was slowly added dropwise. The molar ratio of ammonium formate to (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene was 1-3:1, and the mixture was continuously refluxed and stirred for 24-72 h; the crude product was filtered while hot and then precipitated in a saturated sodium chloride ice aqueous solution. After drying, column chromatography was carried out with dichloromethane and ethyl acetate in a volume ratio of 1:1-3 to obtain the product (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer. Through infrared spectrum and nuclear magnetic spectrum tests, the structure of the obtained compound was proved, and the yield was 80-90%.

[0030] The present invention also provides a (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer.

[0031] The present invention also provides an application of a (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer, and the application of the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer in the preparation of polyimide; wherein, the steps for preparing polyimide include:

[0032] Reacting at 20-30 °C, adding a (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer to a container, and pretreating the diamine monomer with an organosilicon 0.03-0.05 times the molar amount of the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer and 1-1.5 times the crown ether for 24-48 h; subsequently, setting a dropping rate of 0.2-1.0 ml / min to dropwise add an acid anhydride monomer solution. After the addition was completed, the temperature was raised to 80-100 °C and reacted for 3-6 h. Then, pyridine or triethylamine was added as a basic catalyst and the temperature was raised to 180-200 °C and reacted for 3-6 h. The solid content of the reaction system was 15-25%. After cooling to room temperature, the product was poured into ice methanol, washed several times with methanol, and dried in vacuo to obtain polyimide.

[0033] To better explain this solution, the following examples are also provided.

[0034] Example 1

[0035] A preparation method of a (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer, including:

[0036] 1. Under magnetic stirring and nitrogen protection, add 1.00 g of p-tert-butanol, 0.08 g of phosphoric acid, and 5 mL of toluene to a 25 mL three-necked flask. After cooling to 0 °C, add dropwise a toluene solution of 5 mL of nitrophenol (0.5 g). Stir and continue nitrogen protection. Then heat under reflux for 12 h. After cooling to room temperature, precipitate in a saturated sodium chloride ice water solution, and collect the solid by suction filtration. Recrystallize the obtained solid with methanol, filter, and dry it to finally obtain white 2,5-di-tert-butyl-4-nitrophenol powder, with a yield of approximately 85.7%;

[0037] 2. Under magnetic stirring and nitrogen protection, add 0.76 g of p-chloronitrobenzene and 0.08 g of potassium carbonate, and 5 mL of anhydrous methanol to a 25 mL three-necked flask. After cooling to 0 °C, add dropwise a dichloromethane solution of 5 mL of 2,5-di-tert-butyl-4-nitrophenol (0.5 g). Stir and continue nitrogen protection. Heat under reflux for 24 h. After cooling to room temperature, precipitate in a saturated sodium chloride ice water solution, and collect the solid by suction filtration. Recrystallize the solid with methanol, filter, and dry it to obtain yellow (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene crystals, with a yield of 80.5%;

[0038] 3. Under magnetic stirring and nitrogen protection, add 0.5 g of (4)-4-nitrophenoxy-2,5-di-tert-butylnitrobenzene and 0.023 g of palladium-carbon catalyst (Pd / C) to a 25 mL three-necked flask, and 5 mL of 1,4-dioxane. Stir evenly to obtain a suspension. Heat to reflux, and then slowly add dropwise a 5 mL ethanol solution of 25 wt% ammonium formate to the suspension. Continue refluxing and stirring for 24 h. After the reaction is completed, filter the reaction solution while it is hot to remove Pd / C, and then discharge it into a 200 mL saturated sodium chloride ice water solution. After drying, perform column chromatography with a volume ratio of 1:1 dichloromethane and ethyl acetate to obtain the product (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer. The structure of the obtained compound was confirmed by nuclear magnetic spectroscopy, as shown in Figure 1 and Figure 2 shown, with a yield of 82.3%.

[0039] Example 2

[0040] The polyimides were prepared by condensing the (4)-4-aminophenoxy-2,5-di-tert-butylaniline diamine monomer prepared according to Example 1 with the following dianhydride monomers respectively. The specific method is as follows:

[0041]

[0042] Add 0.5 g of (4)-4-aminophenoxy-2,5-di-tert-butylaniline prepared in Example 1 and 2.5 mL of DMAc into a 25 mL three-necked flask equipped with magnetic stirring, nitrogen inlet and outlet, and thermometer. Pre-treat the diamine monomer with 0.03 times the molar amount of organosilicon and 1 time the crown ether for 24 h. Subsequently, set the dropping rate at 1 mL / min and add 2.5 mL of a 0.42 g pyromellitic dianhydride monomer DMAc solution (solid content 18%). After the dropping is completed, raise the temperature to 80 °C and react for 3 h. Then add 0.05 mL of pyridine as a basic catalyst and raise the temperature to 180 °C and react for 3 h. After cooling to room temperature, pour the product into 200 mL of ice methanol, wash it with methanol 3 times, and dry it under vacuum at 80 °C to obtain 0.73 g of polyimide with a yield of 80%. The intrinsic viscosity of the obtained polyimide is 0.81 dL g -1 。

[0043] The polyimide film was subjected to infrared testing, and the test results are as Figure 3 shown. According to Figure 3 it is known that the peak at about 657 cm -1 represents the bending vibration peak of the C=O double bond in the imide group, and the peak at 1386 cm -1 represents the C-N stretching vibration absorption peak in the imide group. Taking PI-13 as an example, the signal peak at about 2932 cm -1 may be the C-H vibration absorption peak of the tert-butyl group in the imide structure, and the peak at about 1670 cm -1 is the carbonyl absorption peak in the imide. In addition, similar characteristic peaks appear in PI-10, PI-11, and PI-12. At the same time, compared with the FT-IR spectra of the traditional pyromellitic dianhydride-based PI films in Chapter 3, there is little difference, and it can be preliminarily inferred that the imide acid is successfully prepared.

[0044] The heat resistance of the polyimide film was tested, and the test results are as Figure 4 and Table 1 show. It can be seen from Figure 4 that there is no obvious thermal weight loss phenomenon before 300 °C. The specific data are summarized in Table 1. With the introduction of the anhydride functional group, the temperatures at which PI-10 to PI-13 have a 5% thermal weight loss are 381 °C, 412 °C, 460 °C, and 480 °C respectively. The thermal stability of the four films from high to low is: PI-10 > PI-11 > PI-12 > PI-13. When the thermal weight loss is 20%, the decomposition temperature of PI-13 can reach 540 °C. The thermal performance data fully show that the heat resistance of the synthesized tert-butyl type polyimide film and the aromatic polyimide film synthesized in the previous part has been significantly improved, proving that the introduction of the tert-butyl structure plays a role in improving the performance of the polyimide. Secondly, with the introduction of functional groups such as C=O and -O- in the monomer structure, the heat resistance of the polyimide film is also improved.

[0045] Table 1 Heat Resistance Data Sheet of Pyromellitic Dianhydride-based Polyimide

[0046]

[0047]

[0048] The surface morphology of the polyimide film was tested, and the test results are as Figure 5 shown. The TEM surface images of PI films synthesized with different structural anhydrides are as Figure 5 shown. It can be seen that there is no obvious change in the overall structure of the four tert-butyl-containing polyimide films. PI-10 shows a flat and smooth surface. The only difference is that PI-11 is a PI / 3,5-ODA / BPDA system, and cotton-like grooves appear in the picture. By analyzing the cross-sectional SEM images ( Figure 5 ), no obvious aggregation was found in PI-11(a, b). At the same time, by comparative analysis Figure 5 of the cross-sections of the four PIs, the middle layers all show relatively smooth surfaces, and the flocculent substances on both sides of the cross-sectional images may be unreacted imide groups.

[0049] The mechanical properties of the polyimide film were tested, and the test results are as Figure 6 and Table 2 shown. According to Figure 6 and Table 2, the tensile stress-time curves of the four tert-butyl-containing polyimide films can be seen. From the figure, it can be seen that their tensile strength is between 90 and 120 MPa, and the modulus is between 2570 and 2620 MPa. The mechanical properties of this part of the synthesized tert-butyl polyimide are similar to those of aromatic polyimides, but the mechanical properties of the tert-butyl polyimide are slightly higher on average. The reason is that the introduction of tert-butyl groups on the polyimide molecular chain leads to an increase in the flexibility of the imide structure and an increase in the disordered arrangement of the polyimide film structure, which increases the tensile strength to a certain extent. At the same time, the introduction of C=O, biphenyl, etc. in the anhydride monomer also increases the rigid structure to a certain extent and can also reduce the tensile strength to a certain extent. Therefore, the tensile strength of the synthesized polyimide film has a relative increase but is not very obvious.

[0050] Table 2 Mechanical Property Data Sheet of Pyromellitic Dianhydride-based Polyimide

[0051]

[0052]

[0053] The dielectric properties of the polyimide film were tested, and the test results are as Figure 7 shown. According to Figure 7It can be seen that as the frequency increases, the dielectric constant will decrease. This may also be because as the electric field frequency increases, the dipoles cannot keep up with the changing frequency in the electric field, resulting in a decrease in the dipole concentration. Thus, macroscopically, the dielectric constant shows an obvious decrease. Moreover, it can be learned from Figure 7 that the dielectric constant range of PI-10 is 2.9 - 3.3 at 1 MHz, indicating that the dielectric constant of the prepared polyimide film containing tert-butyl groups is lower than that of traditional aromatic polyimides. The reason is that the introduction of tert-butyl chains in the imide group increases the free volume of the molecular chain, playing a role in reducing the dielectric constant. In addition, the introduction of functional groups such as benzene rings, -O-, -C=O- in the anhydride structure may greatly reduce the polarizability of the molecule, reducing the packing density and thus leading to a decrease in the dielectric constant. In Figure 7 , the dielectric loss of the polyimide film containing tert-butyl groups is between 0.005 and 0.010 at 1 MHz. PI-11 shows the lowest dielectric loss of about 0.005, which is caused by the differences in molecular structure, conjugation effect and polarizability during the preparation of the polyimide film containing tert-butyl groups. In addition, in Figure 7 , the dielectric loss increases with the increase of frequency within 1 MHz, which is mainly because the conductance loss changes as the frequency continuously increases inside the film. In summary, the preparation of polyimide films containing tert-butyl groups is of great significance for applications in insulating dielectric materials.

[0054] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer, characterized in that, Comprising: Preparing 2,5 - di - tert - butyl - 4 - nitrophenol; Reacting 2,5 - di - tert - butyl - 4 - nitrophenol with p - chloronitrobenzene to prepare (4) - 4 - nitrophenoxy - 2,5 - di - tert - butylnitrobenzene; Reacting (4) - 4 - nitrophenoxy - 2,5 - di - tert - butylnitrobenzene with ammonium formate ethanol solution to prepare (4) - 4 - aminophenoxy - 2,5 - di - tert - butylaniline monomer.

2. The method according to claim 1, characterized in that, Preparing 2,5 - di - tert - butyl - 4 - nitrophenol, comprising: Adding tert - butanol, phosphoric acid, and toluene into a reactor under nitrogen protection to obtain a first solution; After cooling to 0 °C, dropping a nitrophenol toluene solution into the first solution for an electrophilic substitution reaction to obtain a second solution; Adding a saturated sodium chloride ice - water solution into the second solution to obtain a first solid; Recrystallizing the first solid with methanol to obtain 2,5 - di - tert - butyl - 4 - nitrophenol.

3. The method according to claim 2, wherein The molar ratio of the tert - butanol, the phosphoric acid, and the toluene is 1:1 - 2:5 - 10.

4. The method according to claim 2, wherein The mass ratio of nitrophenol to toluene in the nitrophenol toluene solution is 1:10 - 15.

5. The method according to claim 1, characterized in that Reacting 2,5 - di - tert - butyl - 4 - nitrophenol with p - chloronitrobenzene to prepare (4) - 4 - nitrophenoxy - 2,5 - di - tert - butylnitrobenzene, comprising: Adding p - chloronitrobenzene, potassium carbonate, and anhydrous methanol into a reactor under nitrogen protection to obtain a third solution; After cooling to 0 °C, adding 2,5 - di - tert - butyl - 4 - nitrophenol into the third solution for a nucleophilic addition - elimination reaction to obtain a fourth solution; Adding a saturated sodium chloride ice - water solution into the fourth solution to obtain a second solid; Recrystallizing the second solid with methanol to obtain (4) - 4 - nitrophenoxy - 2,5 - di - tert - butylnitrobenzene.

6. The method according to claim 5, characterized in that The molar ratio of the p - chloronitrobenzene, the 2,6 - di - tert - butyl - 4 - nitrophenol, and the potassium carbonate is 1:1 - 2:0.05 - 0.

2.

7. The method according to claim 1, characterized in that Reacting (4) - 4 - nitrophenoxy - 2,5 - di - tert - butylnitrobenzene with ammonium formate ethanol solution for a redox reaction to prepare (4) - 4 - aminophenoxy - 2,5 - di - tert - butylaniline monomer, comprising: Adding (4) - 4 - nitrophenoxy - 2,5 - di - tert - butylnitrobenzene, palladium - carbon catalyst, and 1,4 - dioxane into a reactor under nitrogen protection to obtain a fifth solution; Adding ammonium formate ethanol solution into the fifth solution under heating conditions to obtain a sixth solution; Adding a saturated sodium chloride ice - water solution into the sixth solution to obtain a third solid; Subjecting the third solid to column chromatography with dichloromethane and ethyl acetate in a volume ratio of 1:1 - 3 to obtain (4) - 4 - aminophenoxy 2,5 - di - tert - butylaniline monomer.

8. The method according to claim 7, wherein The mass ratio of the (4) - 4 - nitrophenoxy - 2,5 - di - tert - butylnitrobenzene to the palladium - carbon catalyst is 3 - 8:

1.

9. The method according to claim 7, wherein The mass fraction of the ammonium formate ethanol solution is 25%.

10. (4) - 4 - aminophenoxy - 2,5 - di - tert - butylaniline monomer prepared by any of the methods according to claims 1 - 9.

11. Use of the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer according to claim 10, characterized in that, Application of the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer in preparing polyimide; wherein, the steps for preparing polyimide include: Adding the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer into a container under nitrogen protection, and pretreating the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer with organosilicon and crown ether; Adding an acid anhydride monomer solution and a basic catalyst into the pretreated solution for reaction to obtain a seventh solution; Pouring the seventh solution into ice methanol, and obtaining polyimide by drying.

12. The application according to claim 11, wherein The molar ratio of the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer, the acid anhydride monomer and the basic catalyst is 1:1 to 1.5:0.05 to 0.1; the basic catalyst includes: pyridine or triethylamine; the molar amount of the organosilicon is 0.03 to 0.05 times that of the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer; the molar amount of the crown ether is 1 to 1.5 times that of the (4)-4-aminophenoxy-2,5-di-tert-butylaniline monomer.

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