阅读说明：本技术 一种4,4’-二氨基二苯醚的制备方法 (Preparation method of 4, 4' -diaminodiphenyl ether ) 是由 李希友 胡玉佳 刘昭斌 李智 于贵阳 韩嘉 张奎同 于 2021-09-16 设计创作，主要内容包括：本发明提供了一种4,4’-二氨基二苯醚的制备方法,包括：在孪晶硫化锌镉的催化作用下,4,4’-二硝基二苯醚和水进行光催化加氢反应,得到4,4’-二氨基二苯醚。本申请在制备4,4’-二氨基二苯醚的过程中,反应条件在常温常压下进行,反应过程无需提供额外氢气,通过调控孪晶硫化锌镉催化剂锌镉含量、乙醇浓度及体系酸碱性,使4,4’-二硝基二苯醚在反应40min内全部转化,4,4’-二氨基二苯醚的收率高达99％,催化剂保持良好的稳定性。(The invention provides a preparation method of 4, 4' -diaminodiphenyl ether, which comprises the following steps: under the catalytic action of twin crystal cadmium zinc sulfide, 4,4 '-dinitrodiphenyl ether and water are subjected to photocatalytic hydrogenation reaction to obtain 4, 4' -diaminodiphenyl ether. In the process of preparing 4,4 ' -diaminodiphenyl ether, the reaction conditions are carried out at normal temperature and normal pressure, no additional hydrogen is required in the reaction process, the 4,4 ' -dinitrodiphenyl ether is completely converted in 40min of reaction by regulating and controlling the zinc-cadmium content of the twin crystal zinc-cadmium sulfide catalyst, the concentration of ethanol and the acidity and alkalinity of the system, the yield of the 4,4 ' -diaminodiphenyl ether is up to 99%, and the catalyst keeps good stability.)

1. A method for preparing 4, 4' -diaminodiphenyl ether comprises the following steps:

under the catalytic action of twin crystal cadmium zinc sulfide, 4,4 '-dinitrodiphenyl ether and water are subjected to photocatalytic hydrogenation reaction to obtain 4, 4' -diaminodiphenyl ether.

2. The method according to claim 1, wherein the method for producing 4, 4' -diaminodiphenyl ether comprises:

A) mixing water and ethanol to obtain a homogeneous solution;

B) adding 4, 4' -dinitrodiphenyl ether and twin crystal zinc cadmium sulfide into the homogeneous phase solution, and adjusting the pH value of the obtained system;

C) under the irradiation of visible light in inert atmosphere, the reaction system obtained in the step B) reacts to obtain the 4, 4' -diaminodiphenyl ether.

3. The method according to claim 1 or 2, wherein the ratio of the 4, 4' -dinitrodiphenyl ether to the twinned cadmium zinc sulfide is (1.5 to 75) μmol: (10-50) mg.

4. The preparation method according to claim 1 or 2, wherein the molar ratio of zinc to cadmium in the twin crystal cadmium zinc sulfide is 1:9 to 9:1, expressed as Zn_0.1Cd_0.9S～Zn_0.9Cd_0.1And S has a cubic phase and hexagonal phase twin crystal structure.

5. The method according to claim 2, wherein the pH of the system is 2 to 10, and the agent for adjusting the pH of the obtained system is hydrochloric acid or sodium hydroxide.

6. The method of claim 2, wherein the inert atmosphere is selected from the group consisting of high purity nitrogen and high purity argon.

7. The method according to claim 2, wherein the wavelength of visible light is 420nm or more.

8. The preparation method according to claim 2, wherein the light source of the visible light is a 250-350W xenon lamp.

Technical Field

The invention relates to the technical field of fine chemical engineering, in particular to a preparation method of 4, 4' -diaminodiphenyl ether.

Background

Polyimide is used as a special engineering material and has been widely applied to the fields of aviation, aerospace, microelectronics, nano-scale, liquid crystal, separation membranes, laser and the like. In the last 60 th century, the research, development and utilization of polyimide was listed as one of the most promising engineering plastics in 21 st century in all countries. The great application prospect of polyimide, whether as a structural material or as a functional material, is fully appreciated, and it is believed that "without polyimide, there is no microelectronics today".

4,4 '-diaminodiphenyl ether is an important intermediate for synthesizing polyimide, can increase the flexibility of a polyimide polymer chain and improve the thermal stability of the polyimide polymer chain, and in addition, 4' -diaminodiphenyl ether is also a curing agent for synthesizing epoxy resin, an intermediate of dye and a raw material of perfume, so that the application value is great.

4,4 '-diaminodiphenyl ether is obtained by reducing 4, 4' -dinitrodiphenyl ether, and the existing reduction method mainly comprises five methods: iron powder reduction, stannous chloride-hydrochloric acid reduction, alkali sulfide reduction, hydrazine hydrate reduction, and catalytic hydrogenation reduction. Wherein the yield of the 4, 4' -diaminodiphenyl ether prepared by an iron powder reduction method, a stannous chloride-hydrochloric acid reduction method and a sodium sulfide reduction method is very low, concentrated hydrochloric acid or sodium sulfide aqueous solution is required to be added in the production process, and a large amount of waste liquid and waste residues are generated; although the yield of the hydrazine hydrate reduction method is more than 90 percent, the used hydrazine hydrate is expensive and has strong corrosivity and toxicity. The current industrial common catalytic hydrogenation method mainly depends on noble metal Pd and Pt modified catalyst, such as Pd/C or Pt/C, and high-pressure pure H needs to be introduced₂As a reducing agent, and is required to be highThe reaction condition of temperature has high requirements on reaction equipment, and the production cost is greatly increased.

Disclosure of Invention

The invention aims to provide a preparation method of 4, 4' -diaminodiphenyl ether, and the preparation method provided by the invention is clean, environment-friendly, stable and efficient.

In view of the above, the present application provides a method for preparing 4, 4' -diaminodiphenyl ether, comprising:

under the catalytic action of twin crystal cadmium zinc sulfide, 4,4 '-dinitrodiphenyl ether and water are subjected to photocatalytic hydrogenation reaction to obtain 4, 4' -diaminodiphenyl ether.

Preferably, the preparation method of the 4, 4' -diaminodiphenyl ether specifically comprises the following steps:

A) mixing water and ethanol to obtain a homogeneous solution;

B) adding 4, 4' -dinitrodiphenyl ether and twin crystal zinc cadmium sulfide into the homogeneous phase solution, and adjusting the pH value of the obtained system;

C) under the irradiation of visible light in inert atmosphere, the reaction system obtained in the step B) reacts to obtain the 4, 4' -diaminodiphenyl ether.

Preferably, the ratio of the 4, 4' -dinitrodiphenyl ether to the twin crystal zinc cadmium sulfide is (1.5-75) mu mol: (10-50) mg.

Preferably, the molar ratio of zinc to cadmium in the twin crystal cadmium zinc sulfide is 1: 9-9: 1, and is expressed as Zn_0.1Cd_0.9S～Zn_0.9Cd_0.1And S has a cubic phase and hexagonal phase twin crystal structure.

Preferably, the pH of the system is 2-10, and the reagent for adjusting the pH of the obtained system is hydrochloric acid or sodium hydroxide.

Preferably, the inert atmosphere is selected from high purity nitrogen or high purity argon.

Preferably, the wavelength of the visible light is more than or equal to 420 nm.

Preferably, the light source of the visible light is a xenon lamp of 250-350W.

The application provides a preparation method of 4, 4' -diaminodiphenyl ether, which comprises the following steps: in the twinUnder the catalytic action of the crystal zinc cadmium sulfide, the 4,4 '-dinitrodiphenyl ether and water are subjected to photocatalytic hydrogenation reaction to obtain the 4, 4' -diaminodiphenyl ether. In the process of preparing 4,4 '-diaminodiphenyl ether, the 4, 4' -diaminodiphenyl ether is prepared by a green and environment-friendly photocatalytic means for the first time, the reaction condition does not need high temperature and high pressure, and extra H is provided₂Under the condition of normal temperature and pressure, the 4,4 '-dinitrodiphenyl ether can be reduced into 4, 4' -diaminodiphenyl ether; the zinc cadmium sulfide photocatalyst used in the invention shows high-efficiency photocatalytic reduction performance of 4,4 '-dinitrodiphenyl ether under the condition of no additional noble metal cocatalyst, the yield of 4, 4' -diaminodiphenyl ether can reach 99%, the byproducts are few, and the photocatalyst shows high-efficiency stability in a cycle test.

Drawings

FIG. 1 is a graph showing the yield of 4, 4' -diaminodiphenyl ether over time in the photocatalytic preparation carried out in example 1;

FIG. 2 is a photocatalytic 5 cycle stability test performed in example 1;

FIG. 3 shows a photocatalyst Zn used in example 1_0.7Cd_0.3S has the characterization of a twin structure;

FIG. 4 is a graph showing the conversion curve of 4, 4' -dinitrodiphenyl ether by photocatalysis in examples 2 to 10.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

Aiming at the problems of environmental pollution, high price or high production cost of a catalyst in the preparation process of 4,4 ' -diaminodiphenyl ether in the prior art, the application provides a clean, environment-friendly, stable, efficient, green and economic preparation method of 4,4 ' -diaminodiphenyl ether, and specifically, the embodiment of the invention discloses a preparation method of 4,4 ' -diaminodiphenyl ether, which comprises the following steps:

under the catalytic action of twin crystal cadmium zinc sulfide, 4,4 '-dinitrodiphenyl ether and water are subjected to photocatalytic hydrogenation reaction to obtain 4, 4' -diaminodiphenyl ether.

The 4,4 '-diaminodiphenyl ether is prepared by utilizing a photocatalysis means, selecting a twin crystal type zinc cadmium sulfide solid solution as a photocatalyst, taking 4, 4' -dinitrodiphenyl ether as a raw material and introducing extra H without introducing extra H₂Under the condition, water is used as a solvent to provide hydrogen protons required in the reduction reaction, and the reduction hydrogenation is realized to prepare the 4, 4' -diaminodiphenyl ether under the irradiation of visible light at normal temperature and normal pressure. The twin crystal cadmium zinc sulfide photocatalysis water generates hydrogen protons, the hydrogen protons carry out hydrogenation reduction on the 4,4 ' -dinitrodiphenyl ether, two nitro groups on the 4,4 ' -dinitrodiphenyl ether are hydrogenated and reduced into amino groups, if the hydrogen directly reacts with the 4,4 ' -dinitrodiphenyl ether, a visible light source, a catalyst and a solvent (water and ethanol) are needed, and the three components are all indispensable. The light-excited catalyst makes electrons on the valence band of twin zinc cadmium sulfide collect to the conduction band, so that water generates hydrogen protons, 4' -dinitrodiphenyl ether is reduced, and oxidative holes are left in the valence band, and the sacrificial agent ethanol is reduced to acetaldehyde.

Specifically, the preparation method of 4, 4' -diaminodiphenyl ether described in the present application specifically comprises:

A) mixing water and ethanol to obtain a homogeneous solution;

B) adding 4, 4' -dinitrodiphenyl ether and twin crystal zinc cadmium sulfide into the homogeneous phase solution, and adjusting the pH value of the obtained system;

C) under the irradiation of visible light in inert atmosphere, the reaction system obtained in the step B) reacts to obtain the 4, 4' -diaminodiphenyl ether.

In step A), the ethanol is used as a sacrificial reagent, and the concentration of the ethanol in the homogeneous solution formed by the ethanol is 10-90 vol%, more specifically, the concentration of the ethanol is 30-60 vol%.

According to the invention, after a homogeneous solution has been formed, 4' -dinitrodiphenyl ether and twin-crystal cadmium zinc sulphide are added to adjust the pH of the resulting system(ii) a In the process, the proportion of the 4, 4' -dinitrodiphenyl ether to the twin crystal zinc cadmium sulfide is (1.5-75) mu mol: (10-50) mg; more specifically, the ratio of the 4, 4' -dinitrodiphenyl ether to the twin crystal zinc cadmium sulfide is (5-30) mu mol: (10-30) mg. The twin crystal zinc cadmium sulfide is prepared according to a method well known by a person skilled in the art, wherein the molar ratio of zinc to cadmium is 1: 9-9: 1 and is expressed as Zn_0.1Cd_0.9S～Zn_0.9Cd_0.1And S has a cubic phase and hexagonal phase twin crystal structure. In order to carry out the reaction, hydrochloric acid or sodium hydroxide is adopted to adjust the pH of the system to 2-10, and in a specific embodiment, the pH is 2-6.5.

The method comprises the steps of sealing a reactor of the reaction system, introducing inert gas, exhausting air in the reactor, and then injecting top-illuminated visible light into the reactor, wherein the temperature of the reactor is controlled to be 15-20 ℃, and 4, 4' -diaminodiphenyl ether is obtained after reaction. In the process, the inert atmosphere is selected from high-purity nitrogen or high-purity argon, the light source of the visible light is a xenon lamp of 250-350W, and the wavelength of the visible light is more than or equal to 420 nm. The reaction described herein is carried out at 1atm normal pressure.

The zinc cadmium sulfide with the twin crystal phase provides a high-efficiency and stable catalyst for high yield and high conversion rate of the reaction, and the pH value of a solvent system, a visible light source and a sacrificial agent are all indispensable and all influence the yield and the conversion rate.

For further understanding of the present invention, the following examples are given to illustrate the preparation of 4, 4' -diaminodiphenyl ether provided by the present invention, and the scope of the present invention is not limited by the following examples.

Example 1

Preparing 30 vol% ethanol aqueous solution: adding 30mL of absolute ethyl alcohol into 70mL of water, and performing ultrasonic treatment to form a homogeneous solution; ② adding 5 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 10mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.7Cd_0.3S catalyst, adding 0.1 mol.L into the system^-1Regulating the pH value of the reaction system to 2.12 by HCl, and stirring for 30 min; thirdly, the reactor is sealed and communicatedIntroducing an inert gas N₂Discharging air in the reactor for 30 min; fourthly, a 300W xenon lamp emits visible light with the wavelength of more than or equal to 420nm into a reactor in a top illumination mode, the temperature of the reactor is controlled to be 15 ℃ through water circulation condensation, samples are taken after 40min of reaction, and the quantification is carried out through high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99%, the yield of 4, 4' -diaminodiphenyl ether is more than 99%, and good stability and product yield are still maintained after 5 times of reaction circulation.

FIG. 1 is a graph showing the change of the yield of 4, 4' -diaminodiphenyl ether produced by photocatalysis according to this example with reaction time; as can be seen, the reaction time was longer than 40min, the yield was the highest and remained unchanged.

The inset in fig. 2 is the photocatalytic 5-cycle stability test, and it can be seen from fig. 2 that the catalyst can maintain very high stability in at least five cycles.

FIG. 3 shows the photocatalyst Zn of this example_0.7Cd_0.3S has the characteristic of twin structure.

Example 2

The steps (i), (ii) and (iv) of this example are the same as those of example 1, except that: step three: the reactor was sealed, and the air in the reactor was vented off by introducing inert gas argon for 30 min. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether products is more than 99 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 3

The steps (i), (iii) and (iv) of this example are the same as those of example 1, except that: step two: adding 5 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 10mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.7Cd_0.3S catalyst, adding 0.1 mol.L into the system^-1The reaction pH was adjusted to 4.06 with HCl and stirred for 30 min. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether product is 90 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 4

The steps (ii), (iii) and (iv) of this embodiment are the same as those of embodiment 1, except that: the method comprises the following steps: preparing 50 vol% ethanol aqueous solution: 50mL of absolute ethanol was added to 50mL of water and sonicated to form a homogeneous solution. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether product is 94 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 5

The steps (i), (iii) and (iv) of this example are the same as those of example 1, except that: step two: adding 5 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 20mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.7Cd_0.3S catalyst, adding 0.1 mol.L into the system^-1The reaction pH was adjusted to 2.12 with HCl and stirred for 30 min. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether product is 90 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 6

The steps (i), (iii) and (iv) of this example are the same as those of example 1, except that: step two: adding 10 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 10mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.7Cd_0.3S catalyst, adding 0.1 mol.L into the system^-1The reaction pH was adjusted to 2.12 with HCl and stirred for 30 min. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether product is 90 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 7

The steps (i), (iii) and (iv) of this example are the same as those of example 1, except that: step two: adding 5 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 10mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.7Cd_0.3S catalyst, adding 0.1 mol.L into the system^-1The reaction pH was adjusted to 6.47 with HCl and stirred for 30 min. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether product is 88 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 8

The steps (i), (iii) and (iv) of this example are the same as those of example 1, except that: step two: adding 10 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 10mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.5Cd_0.5S catalyst, adding 0.1 mol.L into the system^-1The reaction pH was adjusted to 2.12 with HCl and stirred for 30 min. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether product is 97 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 9

The steps (i), (iii) and (iv) of this example are the same as those of example 1, except that: step two: adding 10 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 10mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.5Cd_0.5S catalyst, adding 0.1 mol.L into the system^-1The reaction pH was adjusted to 4.06 with HCl and stirred for 30 min. After 40min of reaction, sampling and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, the yield of 4, 4' -diaminodiphenyl ether product is 92 percent, and good stability and product yield are still maintained after 5 times of reaction circulation.

Example 10

The steps (i), (iii) and (iv) of this example are the same as those of example 1, except that: step two: adding 10 mu mol of 4, 4' -dinitrodiphenyl ether reaction raw material and 10mg of twin Zn into 30 vol% ethanol water solution in the step (I)_0.3Cd_0.7S catalyst, adding 0.1 mol.L into the system^-1The reaction pH was adjusted to 2.12 with HCl and stirred for 30 min. Sampling after 40min of reaction and quantifying by high performance liquid chromatography, wherein the conversion rate of 4,4 '-dinitrodiphenyl ether is more than 99 percent, and 4, 4' -diamino-di-tert-butyl etherThe yield of the phenylate product is 93 percent, and the good stability and the product yield are still kept after 5 times of reaction circulation.

FIG. 4 is a graph showing the conversion curve of 4, 4' -dinitrodiphenyl ether by photocatalysis in examples 2 to 10.

The above examples show that: the method provided by the invention can be used for preparing 4,4 '-diaminodiphenyl ether by reducing 4, 4' -dinitrodiphenyl ether at room temperature through the photocatalyst, the process needs the conditions of normal temperature and normal pressure, no hydrogen and noble metal catalyst are added, and the conversion rate of 4,4 '-dinitrodiphenyl ether and the yield of 4, 4' -diaminodiphenyl ether are obviously superior to the efficiency obtained by the traditional industrial method at present, and meet the requirement of green chemistry.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.