阅读说明：本技术 一种硝基苯乙炔选择性催化加氢制备硝基苯乙烯的方法 (Method for preparing nitrostyrene by selective catalytic hydrogenation of nitrobenzene acetylene ) 是由 邓明亮 于 2021-08-13 设计创作，主要内容包括：本发明涉及一种硝基苯乙炔选择性催化加氢制备硝基苯乙烯的方法,所述方法在M-(1)-CuS-(x)催化剂存在下进行,相对于商业使用的Pt/C催化剂加氢生产对乙基苯胺不同,本发明的方法表现出完全不同的加氢选择性,主要对乙炔基团进行加氢,使得硝基苯乙炔选择性加氢得到硝基苯乙烯。本发明还公开了M-(1)-CuS-(x)催化剂及该催化剂的制备方法。(The invention relates to a method for preparing nitrostyrene by selectively catalyzing and hydrogenating nitrobenzene acetylene, which is carried out in M 1 ‑CuS x Compared with the commercial Pt/C catalyst hydrogenation for producing p-ethylaniline, the method of the invention has completely different hydrogenation selectivity, and mainly hydrogenates acetylene groups, so that the nitrobenzene acetylene is selectively hydrogenated to obtain the nitrobenzene-styrene. The invention also discloses M 1 ‑CuS x A catalyst and a preparation method of the catalyst.)

1. Selective hydrogenation preparation of nitrobenzene acetyleneA process for the production of nitrostyrene, comprising: nitrobenzene acetylene is used as a raw material, and is hydrogenated to prepare nitrostyrene under the participation of a catalyst, wherein the reaction pressure is 0.5-10MPa, the reaction temperature is 20-100 ℃, and the catalyst is M₁-CuS_xWherein M is₁The noble metal is M, the noble metal is dispersed in the carrier in an atomic form, the load of M is 0.01 to 40at percent, and the total amount of atoms in the catalyst is calculated; carrier CuS_xIs an amorphous carrier, wherein x is selected from 0.3-5.

2. The process of claim 1 wherein the nitrostyrene is selected from the group consisting of p-nitroacetylene, m-nitroacetylene.

3. The process as claimed in any of claims 1 to 2, wherein the reaction pressure is preferably in the range from 1.5 to 3MPa and the reaction temperature is preferably in the range from 30 to 50 ℃.

4. A process according to any one of claims 1 to 3, wherein M is Pt or Pd and x is preferably from 0.5 to 2.

5. The process of any of claims 1-4 wherein the catalyst is Pt₁-Cu_1.94S or Pd₁-Cu_1.94S。

6. The method of any of claims 1-5, wherein the amorphous CuS_xThe carrier is a nano structure, the size of the nano structure is 5-15nm, preferably 11.4 +/-1.0 nm, and the noble metal M and the carrier form a hollow structure.

7. A process according to any one of claims 1 to 6, wherein the amount of catalyst is from 0.5% to 10% by molar ratio based on the starting materials.

8. M₁-CuS_xApplication of monatomic catalyst in selective hydrogenation reaction of p-nitroacetylene, wherein the catalyst is M₁-CuS_xWherein M is₁Is noble goldThe noble metal M is dispersed in the carrier in an atomic form, and the load of the M is 0.01 to 40at percent, which is calculated by the total molecular weight in the catalyst; carrier CuS_xIs an amorphous carrier, wherein x is selected from 0.3-2.

Technical Field

The invention relates to a method for preparing nitrostyrene by selectively catalyzing and hydrogenating nitrobenzene acetylene, in particular to a method for preparing nitrostyrene by selectively catalyzing and hydrogenating nitrobenzene acetylene in M₁-CuS_xA process for preparing nitrostyrene by selective hydrogenation in the presence of a catalyst.

Background

The selective hydrogenation reaction is widely applied to the fields of fine chemicals, medicines, food additives and the like. The platinum-based and palladium-based noble metal catalysts are widely applied to the aspect of catalyzing selective hydrogenation and other reactions, and the problem that a plurality of selective hydrogenation reactions are difficult to solve is solved by modifying active sites in the platinum-based and palladium-based catalysts. Meanwhile, the loading capacity of active metal in the monatomic catalyst is improved, and the activity and the selectivity of the reaction are expected to be improved. However, in the noble metal monatomic catalyst, it is difficult to ensure atomic-level dispersion when the loading amount of the active metal is increased, and clusters or nanoparticles are easily formed. Therefore, it is still a significant challenge to increase the loading of noble metal monatomic in the catalyst material, and thus to increase the overall activity of the noble metal monatomic catalyst in the selective hydrogenation reaction.

Preparation of monatomic Pt by Liya-Doa team₁CuSx catalyst and found to have catalytic H₂And O₂Direct preparation of H₂O₂The results are disclosed in Chem 5,2019, 2099-2110.

There is still a need in the art for new catalysts, especially monatomic catalysts, with better selective hydrogenation, which are of great interest to the industry because of their high catalytic efficiency and stability.

Disclosure of Invention

The invention discloses a method for preparing nitrostyrene by selectively hydrogenating nitrobenzene acetylene, which comprises the following steps: nitrobenzene acetylene is used as a raw material, and is hydrogenated in the presence of a catalyst to prepare the nitrostyrene.

The nitrostyrene is selected from p-nitroacetylene and m-nitroacetylene.

The catalyst is M₁-CuS_xWherein M is₁Noble metals, preferably Pt and Pd, are dispersed in the carrier in an atomic form, the loading amount of M is 0.01 to 40at percent, the loading amount of Pt is preferably 24.8at percent, and the loading amount of Pd is preferably 26.0at percent, calculated by the total amount of atoms in the catalyst; carrier CuS_xIs an amorphous carrier, wherein x is selected from 0.3-5, preferably 0.5-2, such as CuS_0.51I.e. Cu_1.94S。

Preferably, the amorphous CuS_xThe carrier is a nano structure, the size of the nano structure is 5-15nm, preferably 11.4 +/-1.0 nm, and the noble metal M and the carrier form a hollow structure.

The reaction pressure is 0.5-10MPa, preferably 1.5-3MPa, and the reaction temperature is 20-100 deg.C, preferably 30-50 deg.C.

The amount of the catalyst is 0.5 to 10 percent of the molar ratio based on the raw materials.

The M is₁-CuS_xThe preparation method can be seen in Chem 5,2019,2099-2110 relevant parts.

The preparation method comprises the following steps:

s1: providing a first solution, wherein the first solution is a mixed solution of copper acetate, dodecyl mercaptan and dodecanol;

s2: heating the mixed solution under the protection of inert gas to obtain a mixed solution containing black brown precipitates;

s3: washing the obtained black brown precipitate to obtain Cu_1.94S nanocrystalline;

s4: providing a second solution and a soluble precious metal compound, wherein the solution is a dispersion of the soluble precious metal compound;

s5: providing a third solution of the Cu_1.94S, dispersing liquid of nanocrystalline;

s6: providing a fourth solution, wherein the fourth solution is a mixed solution of the second solution and the third solution, and continuously stirring the fourth solution under the high-temperature condition of inert gas protection, and reducing the temperature to be low;

s7: exposing the mixed solution in the air, continuously stirring, and washing;

in step S1, the first solution is a mixed solution of copper acetate dispersed in dodecanethiol and dodecanol.

In step S2, after removing air with Ar, the heating process is performed for a while, and then the temperature is decreased to room temperature, so as to obtain a mixed solution containing dark brown precipitate. The heating temperature is preferably 200-400 ℃, and the reaction time is preferably 10-50 min.

In step S3, the washing solution is a mixed solution of ethanol and cyclohexane, and the blackish brown precipitate is washed to obtain Cu_1.94And (4) S nanocrystals.

In step S4, the soluble precious metal salts are platinum salts and palladium salts. In the second solution, the noble metal platinum salt and the palladium salt have a molar concentration of 0.33M. Depending on the kind of the noble metal salt, Cu-supported noble metal salts can be obtained_1.94In the embodiment, the noble metal salt is platinum salt and palladium salt, the platinum salt is chloroplatinic acid, and the palladium salt is ammonium chloropalladate.

In step S5, the third solution is Cu_1.94And (3) dispersion liquid of S nanocrystal.

In step S6, the fourth solution is a mixed solution of the second solution and the third solution, and the fourth solution is continuously stirred at a high temperature under the protection of an inert gas, and is cooled to a low temperature. The inert gas is preferably argon or nitrogen, the high-temperature condition is preferably 150-300 ℃, the stirring time is preferably 1-60min, and the low temperature is preferably 20-100 ℃.

In step S7, the stirring time is preferably 1-60min, and the washing solution is ethanol and cyclohexane.

After step S7, the high-loading noble metal monatomic catalyst material is obtained. The high-load noble metal monatomic catalyst material is in a solid powder state. In the single-atom catalyst material, the atomic percentage contents of the noble metals platinum and palladium are respectively 24.8 percent and 26.0 percent, and the mass percentage contents are respectively 61.3 percent and 46.9 percent.

The noun explains:

noble metal: ru, Rh, Pd, Ag, Os, Ir, Pt, Au

M₁-CuS_xIn, M₁Subscript 1 of (a) indicates that the metal M is present in a monoatomic state;

at% represents atomic percentage content;

wt% means weight percent content.

Advantageous effects

The invention provides a method for preparing p-nitroacetylene in M₁-CuS_xThe selective hydrogenation process of preparing p-nitro styrene in the presence of catalyst. Unlike the commercial Pt/C catalyst for catalytic hydrogenation to produce p-ethylaniline, the method of the present invention shows completely different hydrogenation selectivity, and mainly hydrogenates acetylene groups. The catalyst of the invention shows excellent catalytic activity, selectivity and structural stability in the p-nitroacetylene hydrogenation reaction.

Drawings

FIG. 1 shows Cu in example 1 of the present invention_1.94And (3) a Transmission Electron Microscope (TEM) picture of the S nanocrystal supported monatomic platinum catalyst material.

FIG. 2 shows Cu in example 1 of the present invention_1.94And (3) taking a spherical aberration correction high-angle annular dark field scanning transmission electron microscope (AC-HAADF-STEM) photograph of the S nanocrystal supported monatomic platinum catalyst material.

FIG. 3 is a drawing of the present inventionCu_1.94And an L-edge Fourier transform extended absorption fine structure (EXAFS) spectrogram of the S nanocrystal supported monatomic platinum and monatomic palladium catalyst material.

FIG. 4 shows Cu in example 2 of the present invention_1.94And (3) a Transmission Electron Microscope (TEM) picture of the S nanocrystal supported monatomic palladium catalyst material.

FIG. 5 shows Cu in example 2 of the present invention_1.94And (3) taking a spherical aberration correction high-angle annular dark field scanning transmission electron microscope (AC-HAADF-STEM) photograph of the S nanocrystal supported monoatomic palladium catalyst material.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

M used in the invention will be combined with the accompanying drawings and specific embodiments₁-CuS_xThe catalyst and the method for preparing the same are further described in detail.

Preparation of example 1

A. Amorphous Cu_1.94Synthesis of S

a. 80mg of copper acetate was dissolved in a mixed solution of 15ml of dodecanethiol and 5ml of dodecanol to form a solution A (first solution)

b. The air in the above solution was purged with Ar.

c. The mixed solution is heated to 230 ℃, and cooled to room temperature after 20min of reaction.

d. After washing with ethanol and cyclohexane, the dark brown powder was dissolved in 8ml of cyclohexane.

B.Pt₁-CuS_xSynthesis of (2)

a. 512mg of chloroplatinic acid was dissolved in 3mL of ethylene glycol to form solution B (second solution).

b. 0.4ml of Cu_1.94The S solution was added to 4ml of oleylamine to form a solution C (third solution), and after purging the air with Ar, 60. mu.L of the solution B was added to form a solution D (fourth solution).

c. And heating the solution D to 180 ℃, reacting for 5min, cooling to 80 ℃, and adding 9ml of ethanol.

d. Exposing the obtained solution to air, stirring for 45min, and washing with ethanol and cyclohexane to obtain amorphous Cu_1.94A monoatomic platinum catalyst material carried by an S carrier, the atomic load of the platinum being24.8％。

A Transmission Electron Microscope (TEM) photograph of the catalyst of preparation example 1 is shown in FIG. 1, a spherical aberration-corrected high-angle annular dark-field scanning transmission electron microscope (AC-HAADF-STEM) photograph is shown in FIG. 2, and an L-edge Fourier transform extended absorption fine structure (EXAFS) spectrum of Pt is shown in FIG. 3.

Preparation of example 2

A. Amorphous Cu_1.94Synthesis of S

a. 80mg of copper acetate was dissolved in a mixed solution of 15ml of dodecanethiol and 5ml of dodecanol to form a solution A (first solution)

b. The air in the above solution was purged with Ar.

c. The mixed solution is heated to 230 ℃, and cooled to room temperature after 20min of reaction.

d. After washing with ethanol and cyclohexane, the dark brown powder was dissolved in 8ml of cyclohexane.

B.Pd₁-CuS_xSynthesis of (2)

a. 281mg of ammonium chloropalladate was dissolved in 3mL of ethylene glycol to form solution B (second solution).

b. 0.4ml of Cu_1.94The S solution was added to 4ml of oleylamine to form a solution C (third solution), and after purging the air with Ar, 4. mu.L of the solution B was added to form a solution D (fourth solution).

c. Heating the solution D to 180 ℃, reacting for 5min, cooling to room temperature, washing with ethanol and cyclohexane to obtain amorphous Cu_1.94The S carrier supported monatomic platinum catalyst material had a palladium atomic loading of 26.0%.

An L-edge fourier transform extended absorption fine structure (EXAFS) spectrum of Pd in the catalyst of preparation example 2 is shown in fig. 3, a Transmission Electron Microscopy (TEM) photograph is shown in fig. 4, and a spherical aberration corrected high angle annular dark field scanning transmission electron microscopy (AC-HAADF-STEM) photograph is shown in fig. 5.

Example 3 hydrogenation of p-nitroacetophenone Using Pt₁-CuS_xCatalyst and process for preparing same

a. By H₂The autoclave was purged.

b. Adding 9mL of methanol and 0.5mmol of paranitratePhenylphenylacetylene and catalyst containing 0.025mmol Pt (8.78mg of 24.8 at% Pt₁-CuS_xMonatomic catalyst) was placed in a magnetic stirred tank.

c. With 2MPa H₂Pressurizing the high-pressure reaction kettle;

d. the reaction kettle continuously reacts for 8 hours at 40 ℃.

e. The product mixture was determined by gas chromatography using tetradecane (n-tridecane) as internal standard. And performing product identification and gas chromatography correction by using a gas chromatography-mass spectrometry combined technology and a standard solution of the identified product.

Comparative example 4 use of a commercial Pt/C catalyst

The same procedure as in example 3, except that 24.35mg of a 20 wt% Pt/C commercial catalyst was used instead of Pt in example 3₁-CuS_xA catalyst. The Pt/C used was a commercial catalyst available from Johnson Matthey.

The test results were as follows:

from the test results, 8.78mg of 24.8 at% Pt₁-CuS_xWhen the monatomic catalyst is applied to the selective hydrogenation reaction of p-nitroacetylene, the selectivity of p-nitroacetylene is up to 90.2% under the conversion rate of 92%. And 24.35mg of 20 wt% Pt/C in the selective hydrogenation of p-nitroacetylene, the selectivity to p-nitroacetylene is 0at 100% conversion.

In addition, other modifications within the spirit of the invention will occur to those skilled in the art, and it is understood that such modifications are included within the scope of the invention as claimed.