阅读说明：本技术 催化剂 (Catalyst and process for preparing same ) 是由 格雷厄姆·哈钦斯 西蒙·弗里克莱 孙希 于 2019-07-11 设计创作，主要内容包括：本文公开了一种包含单原子分散的阳离子金或钌或钯或铂物质的催化剂及其制备方法。(Disclosed herein are catalysts comprising a monoatomic dispersion of cationic gold or ruthenium or palladium or platinum species and methods of making the same.)

1. A method for preparing a catalyst, the method comprising combining a gold precursor, a ruthenium precursor, a palladium precursor, or a platinum precursor, a solvent, and a support species, wherein the solvent comprises an organic solvent and the solvent does not comprise an organic aqua regia.

2. The method of claim 1, wherein the combining comprises forming a precursor solution in a solvent and combining the solution with the supporting species.

3. The method of claim 1 or 2, wherein the method further comprises drying the product of the step of combining the precursor, the solvent and the loading substance.

4. The method of any one of the preceding claims,

(a) the gold precursor is selected from: elemental gold (Au), chloroauric acids (HAuCl) such as chloroauric acid trihydrate and/or chloroauric acid tetrahydrate₄) Gold (III) chloride (AuCl)₃) Gold (I) chloride (AuCl), gold acetate and combinations of one or more thereof; and/or

(b) The ruthenium precursor is selected from: ruthenium (III) acetylacetonate, combinations thereof, and/or

(c) The palladium precursor is selected from: palladium (II) acetylacetonate, anhydrous palladium (II) nitrate, palladium (II) acetate, and combinations of one or more thereof; and/or

(d) The platinum precursor is: 2, 4-pentanedionatoplatinum (II).

5. The method of any one of the preceding claims, wherein the solvent:

(a) has an E equal to or less than about 62_T(30) Polarity, e.g., E equal to or less than about 60_T(30) Polarity, e.g., E equal to or less than about 55_T(30) Polarity, e.g., E equal to or less than about 50_T(30) Polarity, and/or

(b) Has a boiling point equal to or less than about 120 ℃; and/or

(c) Comprises equal to or less than about 50 vol% water, for example, equal to or less than about 10 vol% water, for example, equal to or less than about 5 vol% water; and/or

(d) Has a pH equal to or greater than about 5, or a pH equal to or greater than about 6.

6. The process according to any one of the preceding claims, wherein the organic solvent is selected from: alcohols, ketones, esters, ethers, sulfoxides, nitriles, amides, and combinations of one or more thereof.

7. The method of any one of the preceding claims, wherein the solvent does not comprise:

(a) inorganic acid, and/or

(b) Nitric acid, and/or

(c) Hydrochloric acid, and/or

(d) A combination of nitric acid and hydrochloric acid, and/or

(e) And (3) water.

8. The method of any one of the preceding claims, wherein the method does not comprise adding a sulfur-containing ligand to the gold precursor, the solvent and the loading substance.

9. A method as claimed in any preceding claim, wherein the support substance comprises carbon, such as activated carbon.

10. A process according to claim 3, wherein the drying is carried out at a temperature above the boiling point of the solvent, for example at a temperature of about 10 ℃ above the boiling point of the solvent.

11. The method of claim 3 or 10, wherein the drying is performed at a temperature of equal to or less than about 120 ℃, such as equal to or less than about 110 ℃, such as equal to or less than about 100 ℃, such as equal to or less than about 90 ℃.

12. A process according to any preceding claim, wherein the catalyst comprises monoatomic and/or cationic gold, ruthenium, palladium or platinum.

13. A catalyst comprising a monoatomic dispersion of a cationic gold, ruthenium, palladium, or platinum species and a support material.

14. The catalyst of claim 13, wherein the catalyst provides a steady state acetylene conversion of greater than about 3%, such as equal to or greater than about 18%.

15. The catalyst of claim 13 or 14, wherein equal to or greater than about 80% of the gold or ruthenium or palladium or platinum is monoatomic.

16. The catalyst of any one of claims 13 to 15, wherein the catalyst comprises a monoatomic dispersion of a cationic gold species and a supporting species, and wherein:

equal to or greater than about 58% gold, for example equal to or greater than about 70% gold, is present in the Au (I) oxidation state, and/or

Equal to or greater than about 60% ruthenium, for example equal to or greater than about 70% ruthenium or equal to or greater than about 80% ruthenium is present in the Ru (III) oxidation state, and/or

Equal to or greater than about 60% of the palladium, for example equal to or greater than about 70% of the palladium or equal to or greater than about 80% of the palladium is present in the Pd (II) oxidation state, and/or

Equal to or greater than about 60% of the platinum, for example equal to or greater than about 70% of the platinum or equal to or greater than about 80% of the platinum is present in the Pt (II) oxidation state, and/or

Equal to or less than about 42% of the gold is present in the oxidation state of Au (III), and/or

Equal to or greater than about 80% of the gold or ruthenium or palladium or platinum is monoatomic;

equal to or less than about 10% of gold or ruthenium or palladium or platinum is present in the nanoparticle form, and/or

Equal to or less than about 10% of gold or ruthenium or palladium or platinum is present in the dimeric form and in the sub-nanocluster form; and/or

The catalyst does not have an X-ray diffraction pattern with 2 Θ reflection angles of one or more of 38 °,44 °,64 °, and 77 °, and/or;

the catalyst has an X-ray diffraction pattern that does not have a 2 theta reflection angle of one or both of 42.2 DEG and 44 DEG, and/or

The X-ray diffraction pattern of the catalyst does not have a 2 theta reflection angle of 40 °; and/or

The X-ray diffraction pattern of the catalyst does not have a 2 theta reflection angle of one or more of 42.9 °,46.4 °,67.9 °,81.8 ° and 86.2 °.

17. A catalyst prepared by the process of any one of claims 1 to 12 and/or obtainable by the process of any one of claims 1 to 12.

18. The catalyst of claim 17, wherein the catalyst has one or more of the features specified in claims 13 to 17.

19. Use of a catalyst according to any one of claims 13 to 18 in the preparation of vinyl chloride.

20. Use according to claim 19, wherein the process for the preparation of vinyl chloride comprises hydrochlorination of acetylene.

Technical Field

The present invention relates generally to a method for producing a supported catalyst (e.g., a supported gold catalyst, a supported ruthenium catalyst, a supported palladium catalyst, or a supported platinum catalyst), and specifically, to a method for producing a carbon-supported catalyst (e.g., a carbon-supported gold catalyst, a carbon-supported ruthenium catalyst, a carbon-supported palladium catalyst, or a carbon-supported platinum catalyst). The invention also relates to the supported catalyst obtained by said method and to the use of said supported catalyst for the preparation of vinyl chloride, for example for the preparation of vinyl chloride by hydrochlorination of acetylene. In particular, the present invention relates generally to methods of making supported gold catalysts, and more particularly to methods of making carbon-supported gold catalysts and catalysts made therefrom. The invention also relates to the use of a supported gold catalyst in the preparation of vinyl chloride, for example by hydrochlorination of acetylene.

Background

Currently, the production of Vinyl Chloride Monomer (VCM), which is the precursor of polyvinyl chloride (PVC), by hydrochlorination of acetylene has become a large-scale industrial process, especially in coal-rich areas such as china. Over 1300 million tons of VCM can be produced annually by acetylene hydrochlorination, the vast majority of which use mercury chloride (HgCl) supported on activated carbon₂) A catalyst. Due to volatile HgCl₂Will come out of the catalyst bedSublimation, which is up to 0.6kg Hg per ton VCM production, causes significant environmental impact from the mercury catalyst. Due to the environmental impact of this process, the most recently approved water license (Minamata conservation) states that all new VCM plants must use mercury-free catalysts and, in the near future, all existing plants must be converted to mercury-free plants. This restores the commercial interest in using gold (Au) and other metals as catalysts for the reaction.

The conditions used to prepare the gold catalyst are believed to affect the characteristics of acetylene hydrochlorination. Generally, to obtain active catalysts, acidic and/or strongly oxidizing solvents are used for carrying out HAuCl₄Impregnation of the precursor. Concentrated nitric acid, concentrated hydrochloric acid and aqua regia (a mixture of nitric acid and hydrochloric acid, typically in a ratio of nitric acid to hydrochloric acid of 1:3v/v) have been used to prepare active catalysts. Comprising organic compounds (e.g., pyridine, N, N-dimethylformamide and imidazole) and sulfoxide chloride (SOCl), known as "Organic Aqua Regia (OAR)"₂) The compositions of (a) have been used as a replacement for acidic and/or strongly oxidizing solvents. However, OARs do not provide a truly environmentally friendly alternative to other methods.

Alternatively, the active catalyst may be prepared in an aqueous medium in the presence of a sulfur-containing ligand. However, the toxicity of sulfur-containing ligands such as thiocyanate salts makes large-scale preparation and use unsuitable.

Accordingly, there is a need to provide alternative and/or improved processes for the preparation of catalysts suitable for the production of vinyl chloride by hydrochlorination of acetylene. Accordingly, there is a need to provide alternative and/or improved processes for the preparation of gold catalysts suitable for the production of vinyl chloride by the hydrochlorination of acetylene.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a method of preparing a catalyst, the method comprising a group alloy precursor, a ruthenium precursor, a palladium precursor or a platinum precursor, a solvent and a support, wherein the solvent comprises an organic solvent and wherein the solvent does not comprise organic aqua regia.

In some embodiments of the first aspect of the present invention, the precursor is a gold precursor.

In some embodiments of the first aspect of the present invention, the precursor is a ruthenium precursor.

In some embodiments of the first aspect of the present invention, the precursor is a palladium precursor.

In some embodiments of the first aspect of the present invention, the precursor is a platinum precursor.

According to a second aspect of the present invention, there is provided a method of preparing a catalyst, the method comprising a group alloy precursor, a solvent and a support substance, wherein the solvent comprises an organic solvent, and wherein the solvent does not comprise organic aqua regia.

In some embodiments of the first aspect of the present invention, the method comprises forming a solution of the precursor in the solvent and combining the solution and the supporting species.

In some embodiments of the second aspect of the present invention, the method comprises forming a solution of gold precursor in the solvent and combining the solution and the supporting species.

In some embodiments of the first aspect of the present invention, the method further comprises drying the product of the step of combining the precursor, solvent and loading substance.

In some embodiments of the second aspect of the present invention, the method further comprises drying the product of the step of combining the gold precursor, solvent and loading substance.

In some embodiments of any aspect of the invention, E of the solvent_T(30) The polarity is equal to or less than about 62. For example, the solvent can have an E equal to or less than about 60_T(30) Polar or have an E equal to or less than about 55_T(30) Polar or have an E equal to or less than about 50_T(30) Polarity.

In some embodiments of any aspect of the present invention, the solvent comprises equal to or less than about 50 vol% water. For example, the solvent may include equal to or less than about 10 vol% water or equal to or less than about 5 vol% water.

In some embodiments of any aspect of the present invention, the solvent has a pH equal to or greater than about 5. For example, the solvent may have a pH equal to or greater than about 6 or a pH equal to or greater than about 7.

In some embodiments of any aspect of the present invention, the solvent has a boiling point equal to or less than about 120 ℃. For example, the solvent may have a boiling point equal to or less than about 100 ℃ or a boiling point equal to or less than about 90 ℃.

In some embodiments of any aspect of the present invention, the support material may comprise, may consist essentially of, or may consist of carbon, such as activated carbon.

According to a third aspect of the present invention there is provided a catalyst comprising a monoatomic dispersion of a cationic gold species and a support species, wherein:

equal to or greater than about 58% of the gold is present in the au (i) oxidation state; and/or

Equal to or less than about 42% of the gold is present in the au (iii) oxidation state; and/or

The catalyst provides a steady state acetylene conversion of greater than about 18%; and/or

Equal to or greater than about 80% of the gold in the catalyst is monoatomic.

According to a fourth aspect of the present invention there is provided a catalyst comprising a monoatomic dispersion of a cationic gold, ruthenium, palladium or platinum species and a support species.

In some embodiments of the fourth aspect of the present invention, the catalyst provides a steady state acetylene conversion of greater than about 18%.

In some embodiments of the fourth aspect of the present invention, equal to or greater than about 80% of the gold or ruthenium or palladium or platinum in the catalyst is monoatomic.

In some embodiments of the fourth aspect of the present invention, equal to or greater than about 58% (e.g., equal to or greater than about 70%) of the gold is present in the au (i) oxidation state.

In some embodiments of the fourth aspect of the present invention, equal to or greater than about 60% (e.g., equal to or greater than about 70% or equal to or greater than about 80%) of the ruthenium is present in the ru (iii) oxidation state.

In some embodiments of the fourth aspect of the present invention, equal to or greater than about 60% (e.g., equal to or greater than about 70% or equal to or greater than about 80%) of the palladium is present in the pd (ii) oxidation state.

In some embodiments of the fourth aspect of the present invention, equal to or greater than about 60% (e.g., equal to or greater than about 70% or equal to or greater than about 80%) of the platinum is present in the pt (ii) oxidation state.

According to a fifth aspect of the present invention there is provided a catalyst obtainable by a process according to any aspect or embodiment of the present invention and/or a catalyst obtainable by a process according to any aspect or embodiment of the present invention. The catalyst of the fifth aspect of the invention may be a catalyst according to the third or fourth aspect of the invention (including any combination of all embodiments of the third or fourth aspect).

In some embodiments of any of the aspects of the invention, equal to or less than about 10% of the gold or ruthenium or palladium or platinum in the catalyst is present in the form of nanoparticles. For example, equal to or less than about 5% of the gold or ruthenium or palladium or platinum in the catalyst is present in the form of nanoparticles.

In some embodiments of any of the aspects of the invention, equal to or less than about 10% of the gold in the catalyst is present in the form of nanoparticles. For example, equal to or less than about 5% of the gold in the catalyst is present in the form of nanoparticles.

In some embodiments of any of the aspects of the invention, equal to or greater than about 80% of the gold or ruthenium or palladium or platinum in the catalyst is monoatomic. For example, equal to or greater than about 90% of the gold or ruthenium or palladium or platinum in the catalyst is monoatomic.

In some embodiments of any of the aspects of the present invention, equal to or greater than about 80% of the gold in the catalyst is monoatomic. For example, equal to or greater than about 90% of the gold in the catalyst is monoatomic.

In some embodiments of any aspect of the present invention, equal to or less than about 10% of the gold or ruthenium or palladium or platinum in the catalyst is present in the form of dimers and sub-nanoclusters. For example, equal to or less than about 5% of the gold or ruthenium or palladium or platinum in the catalyst is present in the form of dimers and sub-nanoclusters.

In some embodiments of any aspect of the present invention, equal to or less than about 10% of the gold in the catalyst is present in the form of dimers and sub-nanoclusters. For example, equal to or less than about 5% of the gold in the catalyst is present in the form of dimers and sub-nanoclusters.

In some embodiments of any aspect of the present invention, the catalyst has an X-ray diffraction pattern that does not have a 2 θ reflection angle of one or more of 38 °,44 °,64 °, and 77 °. This may be particularly applicable to gold catalysts, for example.

In some embodiments of any aspect of the present invention, the catalyst has an X-ray diffraction pattern that does not have a 2 θ reflection angle of one or both of 42.2 ° and 44 °. This may be particularly applicable to ruthenium catalysts, for example.

In some embodiments of any aspect of the present invention, the catalyst has an X-ray diffraction pattern that does not have a 2 θ reflection angle of 40 °. This may be particularly applicable to palladium catalysts, for example.

In some embodiments of any aspect of the present invention, the catalyst has an X-ray diffraction pattern that does not have a 2 θ reflection angle of one or more of 42.9 °,46.4 °,67.9 °,81.8 °, and 86.2 °. This may be particularly applicable to platinum catalysts, for example.

For example, a catalyst according to any aspect or embodiment of the invention (including all combinations of any aspect or embodiment) may provide a steady state acetylene conversion of greater than about 3%. For example, a catalyst according to any aspect or embodiment of the invention (including all combinations of any aspect or embodiment) may provide a steady state acetylene conversion of greater than about 18%.

According to a sixth aspect of the present invention there is provided the use of a catalyst according to any aspect or embodiment (including all combinations of any aspect or embodiment) of the present invention in a process for the production of vinyl chloride, for example in a process for the hydrochlorination of acetylene.

Some embodiments of any aspect of the invention may provide one or more of the following advantages:

good (e.g., improved) activity, e.g., activity for the hydrochlorination of acetylene;

good (e.g., improved) stability, e.g., for acetylene hydrochlorination;

good (e.g., improved) selectivity, e.g., for vinyl chloride;

less severe process conditions (e.g., reduced temperature and/or pressure, less acidic reactants, less number of reactants);

environmentally friendly products and/or processes.

The details, examples and preferences provided for one or more of the various aspects described herein are further described herein and equally apply to all aspects of the invention. Any combination of the embodiments, examples and preferred modes described herein is encompassed by the invention in all possible variations thereof unless otherwise indicated herein or otherwise clearly contradicted by context.

Drawings

The invention may be further described with reference to the following drawings, in which:

fig. 1 shows: a) from HAuCl₄Steady state acetylene conversion by impregnation of 1% Au/C catalyst prepared in various alcohols (. cndot.), ketones (. tangle-solidup.), esters (. diamond-solid.) and aqueous solvents (■); the dotted line shows the activity of the aqua regia catalyst prepared by the conventional method, b) from aboveThe X-ray diffraction patterns of fresh 1% Au/C catalysts prepared from these various solvents were described (test conditions: 90mg catalyst, 23.5mL min)^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^-1Ar，200℃)；

Fig. 2 shows: a) from HAuCl₄The steady state acetylene conversion of 1% Au/C catalyst prepared by the impregnation method in super dry acetone with different amounts of water added; b) the X-ray diffraction patterns of fresh 1% Au/C catalysts prepared from various acetone/water mixtures (test conditions: 90mg catalyst, 23.5mL min^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^-1Ar，200℃)；

FIG. 3 shows the time-in-line acetylene hydrochlorination activity profiles of Au/C-acetone (. tangle-solidup.), Au/C-aqua regia (. circle-solid.) and Au/C-water (. diamond-solid.) catalysts (test conditions: 90mg catalyst, 23.5mL min;)^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^-1Ar，200℃)；

Fig. 4 shows: a) representative STEM-HAADF images of freshly prepared 1% Au/C-acetone material, b) Au L of 1% Au/C-acetone (-fresh) before reaction₃-marginal XANES and 1% Au/C-acetone (-used) Au L after four hours of reaction₃-edge XANES, 1% Au/C-aqua regia and Au L of Au foil₃Edge XANES, C) Au L of 1% Au/C-aqua-regia, 1% Au/C-acetone (fresh) and 1% Au/C-acetone (used)₃Linear combination fitting of edge XANES, d) 1% Au/C-acetone (fresh) and 1% Au/C-acetone (used), k of 1% Au/C-aqua regia and Au foil³Fourier transform of the weight x EXAFS data;

fig. 5 shows: two-day-time on-line acetylene hydrochlorination activity curve of Au/C-acetone (tangle-solidup) and Au/C-aqua regia (■) (test condition: 90mg catalyst, 23.5mL min)^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^{- 1}Ar，200℃)；

FIG. 6 shows X-ray diffraction patterns of catalysts prepared from a noble metal support of 1 wt% Au using various solvents and drying temperatures;

FIG. 7 shows X-ray diffraction patterns of a fresh Au/C-acetone catalyst (fresh), a Au/C-acetone catalyst after four hours of reaction (using 4 hours), and a Au/C-acetone catalyst after three hours of reaction after four hours of reaction (using 7 hours);

FIG. 8 shows the acetylene hydrochlorination activity curve of Au/C-acetone (■) catalyst (test conditions: 90mg catalyst, 23.5mL min)^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^-1Ar，180℃)；

FIG. 9 shows the acetylene hydrochlorination activity curve of Pt/C-acetone (. cndot.) catalyst (test conditions: 90mg catalyst, 23.5mL min)^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^-1Ar，180℃)；

FIG. 10 shows the acetylene hydrochlorination activity curve of Pd/C-acetone (. tangle-solidup.) catalyst (test conditions: 90mg catalyst, 23.5mL min)^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^-1Ar，180℃)；

FIG. 11 shows the acetylene hydrochlorination activity curve of Ru/C-acetone (. diamond-solid.) catalyst (test conditions: 90mg catalyst, 23.5mL min)^-1C₂H₂，23.7mL min^-1HCl and 2.70mL min^-1Ar，180℃)；

FIG. 12 shows k for 1% Au/C-acetone (fresh- ■) and 1% Au/C-acetone (used-xxx) and Au foil (. diamond solid.)³Fourier transform of the weight x EXAFS data;

FIG. 13 shows k for 1% Pt/C-acetone (fresh- ■) and 1% Pt/C-acetone (used-xxx) and Pt foil (. diamond solid.)³Fourier transform of the weight x EXAFS data;

FIG. 14 shows k for 1% Pd/C-acetone (fresh- ■) and 1% Pd/C-acetone (used-xxx) and Pd foil (. diamond solid.)³Fourier transform of the weight x EXAFS data;

FIG. 15 shows k for 1% Ru/C-acetone (fresh- ■) and 1% Ru/C-acetone (used-xxx) and Ru foil (. diamond.)³Fourier transform of the weight x EXAFS data;

FIG. 16 shows representative STEM-HAADF images of freshly prepared 1% Au/C-acetone material;

FIG. 17 shows representative STEM-HAADF images of used 1% Au/C-acetone materials;

FIG. 18 shows representative STEM-HAADF images of freshly prepared 1% Pt/C-acetone material;

FIG. 19 shows a representative STEM-HAADF image of a used 1% Pt/C-acetone material;

FIG. 20 shows representative STEM-HAADF images of freshly prepared 1% Pd/C-acetone material;

FIG. 21 shows a representative STEM-HAADF image of used 1% Pd/C-acetone material;

FIG. 22 shows representative STEM-HAADF images of freshly prepared 1% Ru/C-acetone material;

FIG. 23 shows representative STEM-HAADF images of used 1% Ru/C-acetone materials;

FIG. 24 shows an X-ray diffraction pattern of a fresh Au/C-acetone catalyst;

FIG. 25 shows an X-ray diffraction pattern of a fresh Pt/C-acetone catalyst;

FIG. 26 shows an X-ray diffraction pattern of a fresh Pd/C-acetone catalyst;

FIG. 27 shows an X-ray diffraction pattern of a fresh Ru/C-acetone catalyst;

FIG. 28 shows a Pt foil and Pt (acac)₂Pt L3-edge XANES for Pt/C-acetone before the comparative reaction;

FIG. 29 shows a reaction product with Pd foil and Pd (acac)₂Pd K-edge XANES of Pd/C-acetone before the comparative reaction;

FIG. 30 shows a reaction with Ru foil and Ru (acac)₃Ru K-edge XANES of Ru/C-acetone before the comparative reaction.

Detailed Description

Process for preparing a catalyst

Provided herein is a method of preparing a catalyst. The method includes a group alloy precursor, a ruthenium precursor, a palladium precursor, or a platinum precursor, a solvent, and a support material. The term "precursor" as used herein generally refers to gold precursors, ruthenium precursors, palladium precursors and platinum precursors. For example, the method may include combining a gold precursor, a solvent, and a loading substance. The term "combining" as used herein includes contacting one or more products. For example, the combining may include mixing the products together or stirring the products together.

For example, the process may be referred to as an impregnation process or a wet impregnation process whereby the precursor is impregnated on the catalyst support, e.g., the precursor is dissolved in a solvent and then impregnated on the catalyst support. For example, the method may be referred to as an impregnation method or a wet impregnation method, whereby the gold precursor is impregnated on the catalyst support, e.g., the gold precursor is dissolved in a solvent and then impregnated on the catalyst support. For example, the method may be a micro-wet impregnation method by which the amount of solution used is calculated to be just enough to fill the loaded pores. Thus, the method may comprise forming a precursor solution in a solvent and combining the solution with a supporting species. Thus, the method may comprise forming a gold precursor solution in a solvent and combining the solution with a supporting species. For example, the method may include dissolving the precursor in a solvent and combining the solution with the support species. For example, the method may include dissolving a gold precursor in a solvent and combining the solution with a supporting species. For example, the precursor solution may be combined with the loading substance dropwise, e.g., by stirring or by spraying.

The amount of each of the precursor, solvent, and support species can be selected according to the amount of catalyst desired to be obtained, for example, the amount of each of the precursor, solvent, and support species can be selected according to the desired loading level of gold or ruthenium or palladium or platinum. The amount of each of the gold precursor, solvent, and support species may be selected according to the amount of catalyst desired to be obtained, for example, the amount of each of the gold precursor, solvent, and support species may be selected according to the desired level of gold support.

The combination of precursor, solvent and supported species may be carried out under any suitable conditions. For example, the combination of the gold precursor, solvent, and supported species may be performed under any suitable conditions. For example, the combination may be performed at ambient temperature and/or pressure. For example, the combination may be carried out at a temperature of about 15 ℃ to about 25 ℃. For example, the combination may be carried out under pressure conditions of about 95kPa to about 105kPa (e.g., about 101 kPa). Agitation may be used to combine the precursor, solvent, and support material. Stirring may be used for alloying the precursor, solvent and support material.

The method may further comprise a drying step. For example, the method may further comprise drying the product of the step of combining the precursor, the solvent, and the liability material. For example, the method may further comprise drying the product of the combined steps of the gold precursor, the solvent, and the supported species. For example, the method may further comprise drying to remove the solvent.

For example, drying may occur at a temperature above the boiling point of the solvent. For example, drying can occur at a temperature that is at least about 2 ℃ higher than the boiling point of the solvent, e.g., at least about 3 ℃ higher, e.g., at least about 4 ℃ higher, e.g., at least about 5 ℃ higher. For example, drying may occur at a temperature of about up to 15 ℃, such as up to 12 ℃, for example up to 10 ℃ above the boiling point of the solvent. For example, drying may occur at a temperature of about 2 ℃ to about 15 ℃ above the boiling point of the solvent, e.g., about 5 ℃ to about 10 ℃ above the boiling point of the solvent. For example, drying may occur at a temperature equal to or less than about 120 ℃. For example, drying may occur at a temperature of equal to or less than about 110 ℃, such as equal to or less than about 100 ℃, for example, equal to or less than about 90 ℃. For example, drying may occur at a temperature equal to or greater than about 40 ℃. For example, drying may occur at a temperature equal to or greater than about 50 ℃ or equal to or greater than about 60 ℃. For example, drying may occur at a temperature of about 40 ℃ to about 120 ℃, such as a temperature of about 50 ℃ to about 100 ℃, for example, a temperature of about 60 ℃ to about 90 ℃.

For example, drying may be carried out at or above ambient pressure. For example, the drying may be conducted under pressure conditions of about 95kPa to about 105kPa, for example, under pressure conditions equal to or higher than about 101kPa, for example, under pressure conditions of about 101kPa to about 105 kPa.

For example, drying may continue until the quality of the product no longer changes. For example, drying may continue until all of the solvent has been removed. For example, drying may be continued for up to about 24 hours, for example, up to about 20 hours, for example, up to about 16 hours.

For example, drying may be performed under an inert gas flow. Inert gas refers to a gas that does not react with the catalyst produced by the process described herein. For example, the drying may be under nitrogen (N)₂) The reaction was carried out under air flow.

For example, the method for preparing the catalyst may be a method according to the article by g.malta et al (Science,2017,355, page 1399-1403), the entire content of which is incorporated herein by reference, except that the solvent used is different and optionally different temperatures and/or pressures are used.

For example, the method for preparing the catalyst may not include the use of any other reducing agent. For example, the method for preparing the catalyst may not include an additional step (i.e., a step other than the steps described herein) intended to reduce gold, ruthenium, palladium, or platinum in the catalyst. This may be reflected, for example, in the monoatomic dispersion state of the metal species in the catalyst and/or the oxidation state of the metal in the catalyst. For example, the catalyst may include no or only a small amount of Au (0) or Ru (0) or Pd (0) or Pt (0).

For example, the method for preparing the catalyst may not include the use of a linear or branched olefin fixing agent. For example, the method may not include the use of a fixative. For example, the process for preparing the catalyst may not include a fixed step using linear or branched olefins. For example, the method for preparing the catalyst may not include an immobilization step.

The precursor (i.e., gold precursor or ruthenium precursor or palladium precursor or platinum precursor) can be any compound, including gold, ruthenium, palladium or platinum suitable for preparing a catalyst comprising the monoatomic dispersion of cationic gold, monoatomic dispersion of cationic ruthenium, monoatomic dispersion of cationic palladium or monoatomic dispersion of cationic platinum described herein. For example, the precursor may be dissolved in a solvent used in the method for preparing the catalyst described herein. For example, the precursor may include one or more acetylacetone ligands.

The gold precursor can be any compound that includes gold suitable for preparing a catalyst comprising the monoatomic dispersion of cationic gold described herein. For example, the gold precursor may be dissolved in a solvent used in the method for preparing the catalyst described herein. For example, the gold precursor may include one or more chloride anions.

For example, suitable gold precursors include elemental gold (Au), chloroauric acid (HAuCl)₄) (e.g., chloroauric acid trihydrate and/or chloroauric acid tetrahydrate), gold (III) chloride (AuCl)₃) Gold (I) chloride (AuCl), gold acetate (e.g., gold (III) acetate) (Au (O)₂CCH₃)₃) And combinations of one or more thereof.

Suitable ruthenium precursors include, for example, ruthenium (III) acetylacetonate (Ru (acac)₃) Ruthenium (III) chloride (RuCl)₃) And combinations thereof.

Suitable palladium precursors include, for example, palladium (II) acetylacetonate (Pd (acac)₂) Palladium (II) acetate (Pd (OAc)₂) Anhydrous palladium (II) nitrate (Pd (NO)₃)₂.2H₂O) and combinations of one or more thereof.

Suitable platinum precursors include, for example, platinum (II) acetylacetonate (Pt (acac)₂) It may also be referred to as 2, 4-pentanedionatoplatinum (II).

For example, the solvent can have an E equal to or less than about 62_T(30) Polarity. For example, the solvent can have an E equal to or less than about 60_T(30) Polarity, e.g., E equal to or less than about 58_T(30) Polarity, e.g. E equal to or less than about 56_T(30) Polarity, e.g. E equal to or less than about 55_T(30) Polarity, e.g. E equal to or less than about 54_T(30) Polarity, e.g. E equal to or less than about 52_T(30) Polarity, e.g. E equal to or less than about 50_T(30) Polarity, e.g. E equal to or less than about 48_T(30) Polarity, e.g. E equal to or less than about 46_T(30) Polarity, e.g. E equal to or less than about 45_T(30) Polarity, e.g. E equal to or less than about 44_T(30) Polarity, e.g. E equal to or less than about 42_T(30) Polarity, e.g.E equal to or less than about 40_T(30) Polarity. For example, the solvent can have an E equal to or less than about 50_T(30) Polarity. For example, the solvent can have an E of about 20 to about 60_T(30) Polarity, e.g. E of about 25 to about 55_T(30) Polarity, e.g. E of about 30 to about 50_T(30) Polarity, e.g. E from about 35 to about 50_T(30) Polarity.

Advantageously, the inventors of the present invention have provided a process for preparing gold or ruthenium or palladium or platinum catalysts without the use of strongly acidic or highly oxidizing solvents such as aqua regia and organic aqua regia. Advantageously, the inventors of the present invention have provided a method for preparing gold catalysts without the use of strongly acidic or highly oxidizing solvents such as aqua regia and organic aqua regia. The process for preparing the catalyst disclosed herein also does not require the use of sulfur-containing ligands.

The solvent includes an organic solvent. For example, the solvent may consist essentially of or consist of one or more organic solvents. For example, the organic solvent may be selected from: alcohols, ketones, esters, ethers, sulfoxides, nitriles and amides. For example, the solvent may comprise, may consist essentially of, or may consist of a mixture of different solvents. For example, the solvent may comprise, may consist essentially of, or may consist of a mixture of one or more organic solvents. For example, the solvent may be a non-aqueous solvent. The solvent may be a liquid solvent.

The organic solvent is not organic aqua regia. The term "organic aqua regia" as used herein is meant to encompass (e.g., consist essentially of or consist of) thionyl chloride (SOCl)₂) And solvents of one or more organic compounds such as pyridine, N-dimethylformamide, and imidazole.

The term "alcohol" may relate to any organic compound (R-OH) in which a hydroxyl function (-OH) is bound to carbon. For example, R may be a straight or branched chain or cyclic hydrocarbon, which may be saturated or unsaturated. For example, R may comprise 1 to 20 carbon atoms, such as 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. For example, the alcohols may be selected from: methanol, ethanol, 1-propanol, 2-propanol, n-butanol, sec-butanol, iso-butanol and tert-butanol.

The term "ketone" may relate to any organic compound (R (co) R) comprising a-C ═ O group bonded to two carbon atoms. Each R may independently be a straight or branched chain hydrocarbon, which may be saturated or unsaturated. Each R may independently comprise 1 to 20 carbon atoms, for example 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. Alternatively, the R groups may be linked to form a cyclic molecule, which may be saturated or unsaturated. For example, the cyclic molecule may comprise 1 to 20 carbon atoms, such as 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. For example, the ketones may be selected from: acetone, butanone, pentanone, and hexanones (e.g., cyclohexanone).

The term "ester" may relate to any organic compound (rc (O) OR) comprising a-C (═ O) (OR) group bound to a carbon atom. Each R may independently be a straight or branched chain hydrocarbon, which may be saturated or unsaturated. Each R may independently comprise 1 to 20 carbon atoms, for example 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. Alternatively, the R groups may be linked to form a cyclic molecule, which may be saturated or unsaturated. For example, the cyclic molecule may comprise 1 to 20 carbon atoms, such as 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. For example, the ester may be an alkyl acetate, e.g., ethyl acetate.

The term "ether" may relate to any organic compound comprising an-O-group bound to two carbon atoms (R-O-R). Each R may independently be a straight or branched chain hydrocarbon, which may be saturated or unsaturated. Each R may independently comprise 1 to 20 carbon atoms, for example 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. Alternatively, the R groups may be linked to form a cyclic molecule, which may be saturated or unsaturated. For example, the cyclic molecule may comprise 1 to 20 carbon atoms, such as 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. For example, the ethers may be selected from: dialkyl ethers (where each alkyl group may be the same or different), for example, diethyl ether and tetrahydrofuran.

The term "sulfoxides" may relate to any organic compound comprising a-S (═ O) group, wherein the S atom is bound to two carbon atoms (R-S (═ O) -R). Each R may independently be a straight or branched chain hydrocarbon, which may be saturated or unsaturated. Each R may independently comprise 1 to 20 carbon atoms, for example 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. Alternatively, the R groups may be linked to form a cyclic molecule, which may be saturated or unsaturated. For example, the cyclic molecule may comprise 1 to 20 carbon atoms, such as 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. For example, the sulfoxides can be dialkyl sulfoxides (where each alkyl group can be the same or different), e.g., dimethyl sulfoxide (DMSO).

The term "nitrile" may relate to any organic compound (R-C ≡ N) comprising a-C ≡ N group bonded to a carbon atom. R may be a straight or branched chain hydrocarbon, which may be saturated or unsaturated. R may independently comprise 1 to 20 carbon atoms, for example 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. Alternatively, R may be linked to form a cyclic molecule, which may be saturated or unsaturated. For example, the cyclic molecule may comprise 1 to 20 carbon atoms, such as 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. For example, nitriles may be selected from: alkyl nitriles such as acetonitrile.

The term "amide" may relate to any organic compound comprising a R-C (═ O) -NRR group. Each R may independently be hydrogen or a straight or branched chain hydrocarbon, which may be saturated or unsaturated. Each R may independently comprise 1 to 20 carbon atoms, for example 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. Alternatively, one or more R groups may be linked to form a cyclic molecule, which may be saturated or unsaturated. For example, the cyclic molecule may comprise 1 to 20 carbon atoms, such as 1 to 10 carbon atoms or 1 to 8 carbon atoms or 1 to 6 carbon atoms. For example, the amide may be selected from: dialkylformamides (wherein each alkyl group may be the same or different), for example, Dimethylformamide (DMF).

The hydrocarbons in the alcohols, ketones, esters, ethers, sulfoxides, nitriles, and amides may or may not be substituted with one or more other functional groups.

For example, the solvent may include, consist essentially of, or consist of one or more of the following solvents: methanol, ethanol, propanol, butanol, acetone, butanone, ethyl acetate, diethyl ether, Tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), Dimethylformamide (DMF), and cyclohexanone. For example, the solvent may include, consist essentially of, or consist of one or more of the following solvents: methanol, ethanol, propanol, butanol, acetone, butanone, ethyl acetate, diethyl ether, and Tetrahydrofuran (THF). For example, the solvent may comprise, may consist essentially of, or may consist of acetone.

For example, when the precursor is a gold precursor, the solvent may comprise, may consist essentially of, or may consist of one or more of the following solvents: methanol, ethanol, propanol, butanol, acetone, butanone, ethyl acetate, diethyl ether, Tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), Dimethylformamide (DMF), and cyclohexanone. For example, when the precursor is a gold precursor, the solvent may comprise, may consist essentially of, or may consist of one or more of the following solvents: methanol, ethanol, propanol, butanol, acetone, butanone, ethyl acetate, diethyl ether, and Tetrahydrofuran (THF).

For example, when the precursor is a ruthenium precursor, a palladium precursor, or a platinum precursor, the solvent may comprise, may consist essentially of, or may consist of acetone.

For example, the solvent can comprise equal to or less than about 50 vol% water. For example, the solvent can comprise equal to or less than about 45 vol% water, such as equal to or less than about 40 vol% water, such as equal to or less than about 35 vol% water, such as equal to or less than about 30 vol% water, such as equal to or less than about 25 vol% water, such as equal to or less than about 20 vol% water, such as equal to or less than about 15 vol% water, such as equal to or less than about 10 vol% water, such as equal to or less than about 5 vol% water. For example, the solvent may comprise 0 vol% water. For example, the solvent may comprise 0 vol% to about 50 vol% water, or about 0 vol% to about 30 vol% water or about 0 vol% to about 10 vol% water.

For example, the solvent may have a boiling point equal to or less than about 120 ℃. For example, the solvent may have a boiling point of equal to or less than about 115 ℃ or equal to or less than about 110 ℃ or equal to or less than about 100 ℃ or equal to or less than about 90 ℃ or equal to or less than about 80 ℃. For example, the solvent can have a boiling point equal to or greater than about 40 ℃ or equal to or greater than about 50 ℃ or equal to or greater than about 60 ℃. For example, the solvent may have a boiling point of about 40 ℃ to about 120 ℃, or a boiling point of about 50 ℃ to about 100 ℃, or a boiling point of about 60 ℃ to about 90 ℃.

For example, the solvent may have a pH equal to or greater than about 5. For example, the solvent may have a pH equal to or greater than about 5.5 or a pH equal to or greater than about 6.5 or a pH equal to or greater than about 7 or a pH equal to or greater than about 7.5 or a pH equal to or greater than about 8 or a pH equal to or greater than about 8.5 or a pH equal to or greater than about 9. For example, the solvent may have a pH equal to or less than about 14. For example, the solvent may have a pH equal to or less than about 13.5 or a pH equal to or less than about 13 or a pH equal to or less than about 12.5 or a pH equal to or less than about 12. For example, the solvent may have a pH of about 5 to about 14 or a pH of about 6 to about 13 or a pH of about 6.5 to about 12.

One or more of the following ingredients may not be used in the methods disclosed herein (e.g., the solvent may not include, consist essentially of, and/or consist of one or more of the following ingredients):

an aqueous solution of nitric acid;

an aqueous solution of hydrochloric acid;

an aqueous solution of combined nitric and hydrochloric acids (aqua regia);

an aqueous solution of hydrogen peroxide;

thionyl chloride and pyridine;

thionyl chloride and N, N-dimethylformamide;

thionyl chloride and imidazole;

thionyl chloride and one or more organic compounds;

thionyl chloride;

pyridine;

n, N-dimethylformamide;

imidazole;

a strong acid;

a strong mineral acid;

a sulfur-containing ligand;

1, 10-phenanthroline;

an Au-thiocyanate complex;

schiff base Au (e.g., Au (iii)) complexes of non-gold precursors;

au (e.g., Au (iii)) complexes of non-gold precursors;

sulfates, sulfonates, thioureas, thionyl chloride, mercaptopropionic acid, thiomalic acid, thiosulfates and/or thiocyanates.

In some embodiments, the method for preparing a catalyst described in WO2013/008004 is excluded from the methods for preparing a catalyst disclosed herein. Thus, the methods disclosed herein may exclude a method comprising impregnating a catalyst support material in a solution of gold or a gold compound and a sulfur-containing ligand to form a gold complex and subsequently drying the impregnated support material. For example, the methods disclosed herein may exclude a method comprising impregnating a catalyst support material in a solution of gold or a gold compound and a sulfur-containing ligand to form a gold complex.

By inorganic acid is meant any acid derived from one or more inorganic compounds, including, for example, sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, perchloric acid, and boric acid. A strong acid refers to any acid that dissociates completely in water.

E_T(30) The polarity is represented by C.Reichardt, Agnew. chem. int.ed.,1979,18, pages 98-110, the entire contents of which are incorporated herein by reference.

The catalyst support material may be any support material suitable for preparing a catalyst comprising the monoatomic dispersion of cationic gold or ruthenium or palladium or platinum as described herein. The catalyst support material may be any support material suitable for preparing a catalyst comprising the monoatomic dispersion of cationic gold described herein.

The catalyst support material may, for example, comprise, consist essentially of, or consist of carbon. The carbon may be obtained, for example, from natural sources (e.g., peat, wood, coal, graphite, or combinations thereof). The carbon may be, for example, synthetic carbon. The carbon may be, for example, activated carbon. The activated carbon may have been activated by, for example, steam, acid, or other chemicals. By activated carbon is meant a carbon having a relatively large specific surface area (equal to or greater than about 500 m)²Per g, by N₂Gas adsorption assay). This is believed to be due to the presence of smaller, small volume pores. For example, the activated carbon can have a particle size equal to or greater than about 800m²A specific surface area per gram, e.g. equal to or greater than about 1000m²A specific surface area per gram, e.g. equal to or greater than about 1500m²A specific surface area per gram, e.g. equal to or greater than about 2000m²A specific surface area per gram, e.g. equal to or greater than about 2500m²A specific surface area per gram, e.g. equal to or greater than about 3000m²Specific surface area in g. For example, the carbon may be doped carbon. For example, the carbon may be high purity or ultra-high purity carbon. For example, the carbon may be acid washed to remove impurities.

The catalyst support material may comprise, for example, one or more metal oxides, e.g., zeolites, TiO₂,Al₂O₃,K₂O,ZrO₂,CeO₂,SiO₂And combinations of one or more thereof.

The support material (e.g., carbon such as activated carbon) may be, for example, milled to obtain the desired particle size, and then combined with the precursor and solvent. The support material (e.g., carbon such as activated carbon) may be, for example, milled to obtain the desired particle size, and then combined with the gold precursor and solvent.

The loading substance may be, for example, in powder form, in particulate or granular form of various shapes (e.g., spherical, tablet, cylindrical, multi-lobed cylinder, annular, boulder-like, or a combination of one or more thereof). The catalyst may be in the form of, for example, a monolith.

The loading substance may have an average particle size of, for example, from about 10 μm to about 5 cm. For example, the support material may have an average particle size of from about 20 μm to about 4cm, or from about 30 μm to about 3cm, or from about 40 μm to about 2cm, or from about 50 μm to about 1 cm.

Catalyst and process for preparing same

Also provided herein is a catalyst, which may be obtained or obtainable, for example, by the process described herein (including all embodiments).

The catalyst described herein comprises a monoatomic dispersion of a cationic gold or cationic ruthenium or cationic palladium or cationic platinum species and a support material. The catalysts described herein may include, for example, a monoatomic dispersion of a cationic gold species and a support species. The loading substance may be any loading substance described herein. The monoatomic dispersion of cationic gold or cationic ruthenium or cationic palladium or cationic platinum species can be, for example, in the form of cationic atoms and/or cationic atoms bound to one or more ligands (e.g., ligands from a precursor such as Cl or acetylacetonate), respectively. The monoatomic dispersion of a cationic gold species can be, for example, in the form of cationic gold atoms and/or in the form of cationic gold atoms bound to one or more ligands such as Cl. In some embodiments, the catalyst is not a catalyst described in WO 2013/008004. Thus, in some embodiments, the catalyst is not a catalyst comprising a complex of supported gold and a sulfur-containing ligand and is also not a catalyst comprising supported gold or a compound thereof and trichloroisocyanuric acid or a metal dichloroisocyanurate. In some embodiments, the catalyst is not a catalyst comprising gold or a compound of gold on a support and: a) sulfur, b) compounds of sulfur, or c) trichloroisocyanuric acid or metal dichloroisocyanurates.

Monoatomic dispersions can be observed using a high angle annular dark field scanning transmission electron microscope (HAADF-STEM) as described in the examples below. Dimers, sub-nanoclusters and nanoparticles can also be observed using HAADF-STEM. Assuming that Au (I), Au (III), Ru (III), Pd (II), and Pt (II) are the individual species and Au (0), Ru (0), Pd (0), and Pt (0) are in the form of nanoparticles, the percentage amounts of gold or ruthenium or palladium or platinum that are monoatomic dispersed in the catalyst and the percentage amounts of gold or ruthenium or palladium or platinum that are present in the form of nanoparticles, dimers, and sub-nanoclusters can be calculated from the X-ray absorption data. Assuming that Au (i) and Au (iii) are separate substances and Au (0) is in the form of nanoparticles, the percentage of gold dispersed as monoatomic atoms in the catalyst and the percentage of gold present in the form of nanoparticles, dimers and sub-nanoclusters are calculated from the X-ray absorption data.

Equal to or greater than about 80% of the gold or ruthenium or palladium or platinum in the catalyst may be monoatomic. For example, equal to or greater than about 82% or equal to or greater than about 84% or equal to or greater than about 85% or equal to or greater than about 86% or equal to or greater than about 88% or equal to or greater than about 90% or equal to or greater than about 92% or equal to or greater than about 94% or equal to or greater than about 95% of the gold or ruthenium or palladium or platinum in the catalyst may be monoatomic. For example, up to about 100% or up to about 99% or up to about 98% or up to about 97% or up to about 96% of the gold or ruthenium or palladium or platinum in the catalyst may be monoatomic. For example, from about 80% to about 100%, or from about 85% to about 100%, or from about 90% to about 100%, or from about 95% to about 98% of the gold or ruthenium or palladium or platinum in the catalyst may be monoatomic.

Equal to or greater than about 80% of the gold in the catalyst may be monoatomic. For example, equal to or greater than about 82% or equal to or greater than about 84% or equal to or greater than about 85% or equal to or greater than about 86% or equal to or greater than about 88% or equal to or greater than about 90% or equal to or greater than about 92% or equal to or greater than about 94% or equal to or greater than about 95% of the gold in the catalyst may be monoatomic. For example, up to about 100% or up to about 99% or up to about 98% or up to about 97% or up to about 96% of the gold in the catalyst may be monoatomic. For example, from about 80% to about 100%, or from about 85% to about 100%, or from about 90% to about 100%, or from about 95% to about 98% of the gold in the catalyst may be monoatomic.

Equal to or less than about 10% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of dimers and sub-nanoparticles. For example, equal to or less than about 8% or equal to or less than about 6% or equal to or less than about 5% or equal to or less than about 4% or equal to or less than about 2% or equal to or less than about 1% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of dimers and sub-nanoparticles. For example, 0% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of dimers and sub-nanoparticles. For example, from 0% to about 10% or from 0% to about 5% or from about 1% to about 5% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of dimers and sub-nanoparticles.

Equal to or less than about 10% of the gold in the catalyst may be present in the form of dimers and sub-nanoparticles. For example, equal to or less than about 8% or equal to or less than about 6% or equal to or less than about 5% or equal to or less than about 4% or equal to or less than about 2% or equal to or less than about 1% of the gold in the catalyst may be present in the form of dimers and sub-nanoparticles. For example, 0% of the gold in the catalyst may be present in the form of dimers and sub-nanoparticles. For example, from 0% to about 10% or from 0% to about 5% or from about 1% to about 5% of the gold in the catalyst may be present in the form of dimers and sub-nanoparticles.

Equal to or less than about 10% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of nanoparticles. For example, equal to or less than about 8% or equal to or less than about 6% or equal to or less than about 5% or equal to or less than about 4% or equal to or less than about 2% or equal to or less than about 1% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of nanoparticles. For example, 0% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of nanoparticles. For example, from 0% to about 10% or from 0% to about 5% or from about 1% to about 5% of the gold or ruthenium or palladium or platinum in the catalyst may be present in the form of nanoparticles. These values may correspond to the percentage of gold in the Au (0) or Ru (0) or Pd (0) or Pt (0) oxidation state.

Equal to or less than about 10% of the gold in the catalyst may be present in the form of nanoparticles. For example, equal to or less than about 8% or equal to or less than about 6% or equal to or less than about 5% or equal to or less than about 4% or equal to or less than about 2% or equal to or less than about 1% of the gold in the catalyst may be present in the form of nanoparticles. For example, 0% of the gold in the catalyst may be present in the form of nanoparticles. For example, from 0% to about 10% or from 0% to about 5% or from about 1% to about 5% of the gold in the catalyst may be present in the form of nanoparticles. These values may correspond to the percentage of gold in the Au (0) oxidation state.

Any nanoparticles present in the catalyst may have an average particle size of, for example, from about 1nm to about 100nm, for example from about 2nm to about 50 nm. For example, any nanoparticles present in the catalyst can have an average particle size of about 15nm to about 30nm, such as an average particle size of about 18nm to about 24 nm. This was measured using the Scherrer equation (Scherrer equation) described in the examples below.

The amount of cationic gold or cationic ruthenium or cationic palladium or cationic platinum species in each oxidation state can be identified by X-ray absorption spectroscopy (XANES) in the X-ray absorption near edge structure (XANES) region as described in the examples below. The amount of cationic gold species in each oxidation state can be identified by X-ray absorption spectroscopy (XANES) in the X-ray absorption near edge structure (XANES) region as described in the examples below.

In some embodiments, a majority of the gold in the catalyst is in the au (i) oxidation state.

In some embodiments, a majority of the ruthenium in the catalyst is the ru (iii) oxidation state.

In some embodiments, a majority of the palladium in the catalyst is in the pd (ii) oxidation state.

In some embodiments, a majority of the platinum in the catalyst is in the pt (ii) oxidation state.

Equal to or greater than about 58% of the gold in the catalysts described herein may be present in the au (i) oxidation state. For example, equal to or greater than about 60% or equal to or greater than about 65% or equal to or greater than about 70% or equal to or greater than about 75% of the gold in the catalyst can be present in the au (i) oxidation state. For example, up to about 100% or up to about 95% or up to about 90% or up to about 85% or up to about 80% of the gold in the catalyst may be present in the au (i) oxidation state. For example, from about 58% to about 100% or from about 60% to about 95% or from about 65% to about 90% or from about 70% to about 85% or from about 70% to about 80% or from about 72% to about 78% or from about 75% to about 80% of the gold in the catalyst may be present in the au (i) oxidation state.

Equal to or greater than about 60% of the ruthenium in the catalysts described herein can be present in the ru (iii) oxidation state. For example, equal to or greater than about 65% or equal to or greater than about 70% or equal to or greater than about 75% or equal to or greater than about 80% of the ruthenium in the catalyst can be present in the ru (iii) oxidation state. For example, up to about 100% or up to about 95% or up to about 90% or up to about 85% of the ruthenium in the catalyst may be present in the ru (iii) oxidation state. For example, from about 60% to about 100%, or from about 70% to about 95%, or from about 80% to about 90% of the ruthenium in the catalyst may be present in the ru (iii) oxidation state.

Equal to or greater than about 60% of the palladium in the catalysts described herein may be present in the pd (ii) oxidation state. For example, equal to or greater than about 65% or equal to or greater than about 70% or equal to or greater than about 75% or equal to or greater than about 80% of the palladium in the catalyst may be present in the pd (ii) oxidation state. For example, up to about 100% or up to about 95% or up to about 90% or up to about 85% of the palladium in the catalyst may be present in the pd (ii) oxidation state. For example, from about 60% to about 100%, or from about 70% to about 95%, or from about 80% to about 90% of the palladium in the catalyst may be present in the pd (ii) oxidation state.

Equal to or greater than about 60% of the platinum in the catalysts described herein may be present in the pt (ii) oxidation state. For example, equal to or greater than about 65% or equal to or greater than about 70% or equal to or greater than about 75% or equal to or greater than about 80% of the platinum in the catalyst may be present in the pt (ii) oxidation state. For example, up to about 100% or up to about 95% or up to about 90% or up to about 85% of the platinum in the catalyst may be present in the pt (ii) oxidation state. For example, from about 60% to about 100%, or from about 70% to about 95%, or from about 80% to about 90% of the platinum in the catalyst may be present in the pt (ii) oxidation state.

Equal to or less than about 42% of the gold in the catalysts described herein may be present in the au (iii) oxidation state. For example, less than about 40% or equal to or less than about 35% or equal to or less than about 30% or equal to or less than about 25% of the gold in the catalyst can be present in the au (iii) oxidation state. For example, equal to or greater than about 0% or equal to or greater than about 1% or equal to or greater than about 2% or equal to or greater than about 5% or equal to or greater than about 10% or equal to or greater than about 15% or equal to or greater than about 20% of the gold in the catalyst may be present in the au (iii) oxidation state. For example, from 0% to about 42% or from about 2% to about 40% or from about 5% to about 35% or from about 10% to about 30% or from about 15% to about 25% or from about 20% to about 25% of the gold in the catalyst may be present in the au (iii) oxidation state.

The ratio of au (i) and au (iii) in the catalyst can be, for example, equal to or greater than about 1. For example, the ratio of au (i) and au (iii) in the catalyst can be equal to or greater than about 1.5 or equal to or greater than about 2 or equal to or greater than about 2.5 or equal to or greater than about 3. For example, the ratio of au (i) and au (iii) in the catalyst can be up to about 5.

For example, all of the gold (i.e., 100%) in the catalyst may be present in the au (i) or au (iii) oxidation state. Alternatively, for example, some gold in the catalyst may be present in other oxidation states (e.g., Au (0)). For example, up to about 10% or up to about 8% or up to about 6% or up to about 5% or up to about 4% or up to about 2% of the gold in the catalyst is present in one or more oxidation states other than Au (i) and Au (iii) (e.g., Au (0) oxidation state). Equal to or less than about 10% or equal to or less than about 8% or equal to or less than about 6% or equal to or less than about 5% or equal to or less than about 4% or equal to or less than about 2% of the gold in the catalyst may be present in the Au (0) oxidation state.

All values within the percentage ranges disclosed herein may be selected with all ingredients totaling a total percentage of 100%.

The element gold (Au (0)) can be identified by the presence of 2 θ reflection angles of 38 °,44 °,64 ° and 77 ° in the X-ray diffraction pattern.

Elemental ruthenium (Ru (0)) can be identified by the presence of 2 θ reflection angles of 42.2 ° and 44 ° in the X-ray diffraction pattern.

Elemental palladium (Pd (0)) can be identified by the presence of a 2 θ reflection angle of 40 ° in the X-ray diffraction pattern.

Elemental platinum (Pt (0)) can be identified by the presence of 2 θ reflection angles of 42.9 °,46.4 °,67.9 °,81.8 °, and 86.2 ° in the X-ray diffraction pattern.

The use of a solvent as described herein is believed to improve the dispersion of the gold or ruthenium or palladium or platinum species in the catalyst, thus reducing the form of Au or Ru or Pd or Pt nanoparticles present in the catalyst, respectively. The use of the solvents described herein is believed to improve the dispersion of the gold species in the catalyst and thus reduce the formation of Au nanoparticles present in the catalyst. Therefore, the diffraction peak corresponding to the metal Au or Ru or Pd or Pt is reduced relative to a catalyst prepared from other solvents, particularly a catalyst prepared from an aqueous solvent such as water. Therefore, diffraction peaks corresponding to metallic Au (having 2 θ reflection angles of 38 °,44 °,64 °, and 77 ° in an X-ray diffraction pattern) are reduced relative to catalysts prepared from other solvents, particularly aqueous solvents such as water. Therefore, the diffraction peaks corresponding to metallic Ru (2 θ reflection angles of 42.2 ° and 44 ° in X-ray diffraction pattern) are reduced relative to catalysts prepared from other solvents, especially catalysts prepared from aqueous solvents such as water. Therefore, the diffraction peak corresponding to metallic Pd (2 θ reflection angle of 40 ° in X-ray diffraction pattern) is reduced relative to a catalyst prepared from other solvents, particularly a catalyst prepared from an aqueous solvent such as water. Therefore, diffraction peaks corresponding to metallic Pt (having 2 θ reflection angles of 42.9 °,46.4 °,67.9 °,81.8 °, and 86.2 ° in an X-ray diffraction pattern) are reduced relative to catalysts prepared from other solvents, particularly aqueous solvents such as water. Thus, in some embodiments, the X-ray diffraction pattern of the catalyst does not include 2 θ reflection angles of one or both of 42.2 ° and 44 °. Thus, in some embodiments, the X-ray diffraction pattern of the catalyst does not include a 2 θ reflection angle of 40 °. Thus, in some embodiments, the X-ray diffraction pattern of the catalyst does not include 2 θ reflection angles of one or more of 42.9 °,46.4 °,67.9 °,81.8 °, and 86.2 °. Thus, in some embodiments, the X-ray diffraction pattern of the catalyst does not include 2 θ reflection angles of one or more of 38 °,44 °,64 °, and 77 °. In some embodiments, the X-ray diffraction pattern of the catalyst does not include 2 θ reflection angles of at least 64 ° and 77 °.

The catalysts described herein are believed to have improved dispersancy and therefore improved activity relative to catalysts prepared using other solvents, particularly aqueous solvents such as water. Thus, the catalyst can provide a steady state acetylene conversion of equal to or greater than about 3%. For example, the catalyst can provide a steady state acetylene conversion of equal to or greater than about 5% or equal to or greater than about 10% or equal to or greater than about 15% or equal to or greater than about 18% or equal to or greater than about 20%. For example, the catalyst may provide a steady state acetylene conversion of up to about 30%, or up to about 25%. For example, the catalyst can provide a steady state acetylene conversion of about 3% to about 30%, for example, about 18% to about 25%, or about 19% to about 25%, or about 20% to about 25%.

Steady state acetylene conversion refers to the maximum percent conversion achieved when the catalyst is used in the acetylene hydrochlorination process described in the examples below.

The catalysts described herein can, for example, have a gold or ruthenium or palladium or platinum loading level of from about 0.01% to about 2% based on the total weight of the catalyst. For example, the catalysts described herein may have a gold or ruthenium or palladium or platinum loading level of about 0.1 wt% to about 1.5 wt%, or about 0.5 wt% to about 1 wt%.

The catalysts described herein can, for example, have a gold loading level of about 0.01% to about 2% based on the total weight of the catalyst. For example, the catalysts described herein may have a gold loading level of about 0.1 wt% to about 1.5 wt%, or about 0.5 wt% to about 1 wt%.

Use of the catalyst

The catalysts described herein may be used, for example, as catalysts or may be used in chemical processes. The catalysts described herein can be used, for example, in processes for the production of vinyl chloride, especially in processes for the production of vinyl chloride by hydrochlorination of acetylene.

Any suitable conditions for acetylene hydrochlorination may be used and any suitable conditions for acetylene hydrochlorination may be selected by the person of ordinary skill in the art using common general knowledge. These conditions may be, for example, the conditions described in the article by G.Malta et al (G.Malta et al, Science,2017,355, pages 1399-1403).

The catalysts described herein can also be used for hydrochlorination of other alkynes or substituted alkynes (e.g., alkynes having 2 to 20 carbon atoms, e.g., alkynes having 2 to 10 carbon atoms or 2 to 8 carbon atoms, or 2 to 6 carbon atoms). The catalysts described herein relate to hydrochloric acid and/or chlorine (e.g., Cl)₂) May also be useful in other reactions.

The following paragraphs define specific embodiments of the invention.

1. A method for preparing a catalyst, the method comprising combining a gold precursor, a solvent, and a support material, wherein the solvent comprises an organic solvent and the solvent does not comprise organic aqua regia.

2. The method of paragraph 1 wherein the combining comprises forming a solution of gold precursor in a solvent and combining the solution with the supporting species.

3. The method of paragraph 1 or 2, wherein the method further comprises drying the product of the step of combining the gold precursor, the solvent and the supported species.

4. The method of any preceding paragraph, wherein the gold precursor is selected from: elemental gold (Au), chloroauric acids (HAuCl) such as chloroauric acid trihydrate and/or chloroauric acid tetrahydrate₄) Gold (III) chloride (AuCl)₃) Gold (I) chloride (AuCl), gold acetate and combinations of one or more thereof.

5. The method of any preceding paragraph, wherein the solvent has an E equal to or less than about 62_T(30) Polarity, e.g., E equal to or less than about 60_T(30) Polarity, e.g., E equal to or less than about 55_T(30) Polarity, e.g., E equal to or less than about 50_T(30) Polarity.

6. The method of any preceding paragraph, wherein the solvent has a boiling point equal to or less than about 120 ℃.

7. A method as in any preceding paragraph, wherein the organic solvent is selected from: alcohols, ketones, esters, ethers, sulfoxides, nitriles, amides, and combinations of one or more thereof.

8. A method as in any preceding paragraph, wherein the solvent does not include nitric acid and/or does not include hydrochloric acid and/or does not include a combination of nitric acid and hydrochloric acid.

9. A method as in any preceding paragraph, wherein the method does not comprise adding a sulfur-containing ligand to the gold precursor, the solvent and the loading substance.

10. A method as in any preceding paragraph, wherein the solvent does not include a strong mineral acid.

11. The method of any preceding paragraph, wherein the solvent comprises equal to or less than about 50 vol% water, for example, equal to or less than about 10 vol% water, for example, equal to or less than about 5 vol% water.

12. The method of any preceding paragraph, wherein the solvent does not include water.

13. The method of any preceding paragraph, wherein the solvent has a pH equal to or greater than about 5 or equal to or greater than about 6.

14. A method as in any preceding paragraph, wherein the supporting substance comprises carbon, such as activated carbon.

15. The method of any preceding paragraph, wherein the drying is carried out at a temperature above the boiling point of the solvent.

16. The method of paragraph 3 or paragraph 15 above, wherein the drying is carried out at a temperature about 10 ℃ above the boiling point of the solvent.

17. The method of any of preceding paragraphs 3, 15 or 16, wherein the drying is carried out at a temperature of equal to or less than about 120 ℃, such as equal to or less than about 110 ℃, such as equal to or less than about 100 ℃, such as equal to or less than about 90 ℃.

18. A catalyst comprising a monoatomic dispersion of a cationic gold species and a support species, wherein:

equal to or greater than about 58% of the gold is present in the oxidation state of Au (I), and/or

Equal to or less than about 42% of the gold is present in the oxidation state of Au (III), and/or

The catalyst provides a steady state acetylene conversion of greater than about 18%, and/or

Equal to or greater than about 80% of the gold is monoatomic.

19. The catalyst of paragraph 18 wherein:

equal to or less than about 10% of the gold is present in the form of nanoparticles, and/or

Equal to or greater than about 80% of the gold is monoatomic, and/or

Equal to or less than about 10% of the gold is present as dimers and sub-nanoclusters; and/or

The catalyst has an X-ray diffraction pattern that does not have a 2 theta reflection angle of one or more of 38 °,44 °,64 ° and 77 °.

20. The catalyst of paragraph 18 or 19, wherein the catalyst provides a steady state acetylene conversion of greater than about 3%, for example equal to or greater than about 18%.

21. A catalyst obtainable by the process of any of paragraphs 1 to 17 and/or a catalyst obtainable by the process of any of paragraphs 1 to 17.

22. The catalyst of paragraph 21 wherein the catalyst has one or more of the features of paragraphs 18 to 20.

23. Use of a catalyst as described in any of paragraphs 18 to 22 in a process for the preparation of vinyl chloride.

24. The use as described in paragraph 23 wherein the process for the production of vinyl chloride comprises hydrochlorination of acetylene.

Examples

Example 1

Method of producing a composite material

Preparation of the catalyst

All carbon supported gold catalysts were prepared by the impregnation method described in the article by g.malta et al (g.malta et al, Science,2017,355, pages 1399 to 1403), except that the solvents used were different. Firstly, activated carbon (C)ROX 0.8) to obtain powder (150-200 mesh). Gold precursor (HAuCl)₄·3H₂O (Alfa Aesar,20mg, content 49%)) was dissolved in the desired solvent (2.7 ml). The gold precursor solution was added dropwise to activated carbon (0.99g) to obtain a catalyst with a final metal loading of 1 wt%. At the boiling temperature of the solvent used, in N₂The resulting powder was dried in a stream of air for 16 hours. The catalysts prepared using different solvents were labeled Au/C- (solvent) and, as far as possible, a solvent sold as "ultra-dry solvent" sealed in nitrogen was used.

Solvent used, its E_T(30) The polarity, boiling point and associated drying temperatures are listed in table 1 below.

TABLE 1

Catalyst testing

The catalyst was tested for acetylene hydrochlorination in a fixed bed polyimide (Kapton) microreactor (o.d.6mm, length 20cm) contained within a heating block powered by two heating cartridges inside it. The temperature was controlled by a europeanium (Eurotherm) controller with a type K thermocouple located in the center of the heating block. Using a dehumidifier pair C₂H₂the/Ar (5.01% in Ar equilibrium, BOC) and HCl/Ar (5.05% in Ar equilibrium, BOC) gases were dried and then introduced into the reactor. In all cases, the reactor was purged with Ar (99.99% BIP, gas product) and then the hydrochlorination reaction mixture was contained. The reactor was heated to 200 ℃ at a ramp rate of 5 ℃/min and held at that temperature for 30 minutes, all under Ar gas flow (50 ml/min). C is to be₂H₂/Ar(23.56ml min^-1),HCl/Ar(23.76ml min^-1) And additional Ar (2.70ml min)^-1) The resulting reaction gas mixture was introduced into a heated reactor chamber containing a catalyst (90mg) at a total Gas Hourly Space Velocity (GHSV) of about 17,600/hr, and C was added₂H₂The ratio to HCl was maintained at a constant value of 1: 1.02. Typical time for the gas flow experiment was 240 minutes (4 hours). The gas phase products were analyzed on-line using a Varian450 GC equipped with a Flame Ion Detector (FID). The product was chromatographed and characterized using a Porapak N packing column (6 ft. times. 1/8' stainless steel). Under the reaction conditions used, 100% C₂H₂Conversion of (2) yields 35.33mol kg_cat ^-1h^-1The yield of VCM of (1). The experimental error in acetylene conversion in the replicate test was ± 1%.

Characterization of the catalyst

Powder X-ray diffraction (XRD) patterns were obtained using an X' Pert Pro PAN analysis powder diffractometer using a Cu K run at 40keV and 40mA_αRadiation of radiationA source. The profile was analyzed using X' Pert High Score Plus software. Where possible, the average grain size of metallic gold nanoparticles was determined using the scherrer equation, assuming that the particle shape was spherical and the K-factor of the reflection generated from the Au (111) crystal plane family under the condition of 2 θ ═ 38 ° was 0.89.

In transmission mode, Au L was recorded under a B18 Light beam from Diamond Light Source (Harwell, UK)₃X-ray absorption Structure (XAS) spectra of all Au/C samples at the absorption edge. Measurements were made using QEXAFS set by a fast scan Si (111) bicrystal monochromator. The Demeter software package (Athena and Artemis) was used for XAS data analysis of Au/C absorption spectra, compared to standards against Au foil.

Materials for Scanning Transmission Electron Microscopy (STEM) detection were dry dispersed on a porous TEM carbon mesh. These load components were detected using BF-STEM and HAADF-STEM modes in an aberration corrected JEOL ARM-200CF scanning transmission electron microscope operating at 200 kV. The microscope was also equipped with a Centurio Silicon Drift Detector (SDD) system for X-ray spectroscopy (XEDS) analysis.

Results

It has been previously reported that by HAuCl₄The impregnation method for preparing Au/C catalyst from aqueous solution generates a large amount of Au nanoparticles in the catalyst. These catalysts are almost inactive to acetylene hydrochlorination under these diluted reaction conditions (see Liu et al, Catal. Sci. technol.,2016,6, p. 5144-5153).

The 1 wt% Au/C catalyst was prepared by the method described herein above without the need for a strongly oxidizing solvent or the formation of a stable complex with sulfur-containing ligands.

At GHSV of 17,600h^-1Under conditions determined by a series of conditions such as C₁-C₄The steady state acetylene hydrochlorination activity of the catalyst obtained from solvent preparation such as alcohols is shown in figure 1 a. The acetylene hydrochlorination activity of the catalyst increases from 3% conversion of the catalyst prepared from aqueous solvent to C with an increase in the chain length of the alcohol used in the preparation and a consequent decrease in the polarity of the solvent₄The sample obtained by alcohol preparationConversion of product 20%. In addition to ethers such as Tetrahydrofuran (THF), ethyl acetate and diethyl ether, ketones such as acetone and 2-butanone were also examined, to investigate the effect of further decreasing the polarity, which resulted in a slight increase in conversion to 23%. The Au/C catalyst prepared by the same method as described above but using aqua regia solvent has a steady state conversion of 18%, which means that it is prepared from easily handled low polarity solvents such as acetone, 2-butanol and THF by simple HAuCl₄The performance of the catalyst prepared by the impregnation method is superior to that of the catalyst prepared under the strongly acidic oxidizing condition. All catalysts tested showed high selectivity to vinyl chloride monomer(s) (ii)>99％)。

As the polarity of the impregnation solvent decreases, the activity is relatively stable at about 20% to 24%, the relatively stable level of activity representing a practical limit to the achievable dispersibility of the Au-chloride species. FIG. 1b shows X-ray diffraction patterns of samples prepared from a series of solvents of different polarity. In the samples prepared from the aqueous solvent by the dipping method, the reflections of 2 θ -38 °,44 °,64 ° and 77 ° can be clearly seen, which correspond to the face-centered cubic structure of metallic Au, and calculated by using the scherrer equation, which corresponds to an average grain size of 20 nm. These features are present in the catalyst samples prepared from highly polar solvents, whose reflection angles show an average nanoparticle size of 18-24 nm. As the polarity of the solvent decreases, a gradual decrease in the intensity of these reflection angles can be seen, indicating a higher dispersion of Au in the catalyst, corresponding to an increase in activity. The sample with the highest activity showed a very weak or undetectable diffraction peak corresponding to metallic Au, indicating a high dispersion of the cationic Au and supporting the following hypothesis: au nanoparticles are not active species for this reaction.

The reason why the catalyst prepared from a low-polarity organic solvent has high activity when the solvent used is not strongly acidic or oxidative is that: (i) the hydrophilicity/hydrophobicity of the solvent itself, which provides more wetting of the carbon support, resulting in higher dispersibility, (ii) the ability to use lower drying temperatures, thus preventing Au aggregation, and (iii) the complete absence of water during the catalyst preparation process. To confirm this view, we further investigated the use of low polarity solvents with high boiling points, for example, Dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and cyclohexanone. Table 2 lists the polarity, boiling point and drying temperature and acetylene conversion used to prepare these catalysts.

TABLE 2

And (3) testing conditions are as follows: 90mg catalyst, 23.5mL min^-1C₂H₂,23.7mL min^-1HCl and 2.7mL min^-1Ar,200℃.

Catalyst and process for preparing same	Polarity (E)T(30))	Boiling point (. degree.C.)	Drying temperature (. degree.C.)	Acetylene conversion (%)
					Au/C-DMSO	45.0	189	195	14
Au/C-DMF	43.8	154	160	8
					Au/C-Cyclohexanone	40.8	155	160	3
Au/C-acetone	42.2	56	40	22
					Au/C-acetone	42.2	56	140	22

Although all catalysts prepared from high boiling (>120 ℃) solvents performed better than catalysts prepared in aqueous solution, the catalysts prepared from high boiling (>120 ℃) solvents did not have the same activity as the samples prepared from low boiling (<120 ℃) solvents, indicating that drying temperature is also a parameter affecting catalyst performance. XRD analysis (fig. 6) showed that the catalyst prepared at high drying temperature contained Au nanoparticles, consistent with its lower activity. To demonstrate whether drying temperature is the only variable determining high activity and dispersion, the catalyst was prepared using acetone and dried at 140 ℃ for 16 hours. As shown in table 2, the catalyst showed equivalent activity to the acetone prepared sample and dried at 40 ℃, indicating that effective catalysts can be prepared using low polarity solvents at low drying temperatures, but these same catalysts are still stable and active even at higher drying temperatures. This demonstrates that the increased wettability of the impregnation solution on the carbon support, coupled with moderate drying conditions, is effective to lock in the only higher dispersed Au species, rather than the formation of species solely determined by the drying temperature.

We further investigated the effect of water present when using purchased ultra-dry acetone to prepare the catalyst without any further treatment. The addition of more and more water (5-50 vol%) to acetone resulted in a decrease of the activity of the catalyst thus prepared, which was similar to the activity of the sample prepared in aqueous solution, as shown in figure 2a, by the addition of 50 vol% water to acetone. This reduction in activity is closely related to the generation of characteristic peaks of metallic Au in the XRD pattern (fig. 2 b). This demonstrates the adverse effect of the presence of water in order to stabilize the supported Au in a highly oxidized state in the absence of strong oxidizing/acidic reagents or ligands on the preparation of highly dispersible Au catalysts.

Time on-line studies were performed to compare the activity of the less polar Au/C-acetone catalyst and the acidic Au/C-aqua regia species and the more polar Au/C-H₂Activity of the O catalyst. Figure 3 shows the high stability of the Au/C-acetone catalyst under the reaction conditions with a slight increase in conversion (3%) in the first 100 minutes, indicating that a small change in the Au oxidation state is possible and a minimum induction period is required followed by 140 minutes for stable conversion. The comparative Au/C-aqua regia catalyst underwent a significant induction period due to the change in Au oxidation state (studied in situ XAS above), resulting in a 15% difference in conversion over the same timeframe. Thus, the oxidative aqua regia solvent resulted in a lower final conversion of the catalyst relative to milder acetone prepared catalysts, which clearly indicates that the different functional groups supported on carbon may play a role in determining the induction period of these catalysts by stronger Au anchoring oxidation state or promoting oxidation state changes more easily.

Further characterization of the 1% Au/C-acetone catalyst by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) revealed that the Au species were mostly monoatomic dispersed Au species with some incidental dimeric Au species and sub-nanoclusters, but there was no evidence of larger Au crystallites produced. An exemplary image is shown in fig. 4 a.

To further confirm the Au species formed in the catalyst, we performed in Au L₃X-ray absorption spectroscopy was performed at the edge (11.92 keV). In addition to the Au/C-aqua regia catalyst, the Au-L of a fresh Au/C-acetone catalyst was recorded₃Edge X-ray absorption spectrum and Au-L after 5 hours of reaction₃Edge X-ray absorption spectra and analysis was performed in the X-ray absorption near edge structure (XANES) region. Corresponds to Au 2p_3/2Analysis of normalized white line intensity of the → 5d primary transition can be used as direct evidence of 5d occupancy by the Au species present in the catalyst. Quantitative determination of the identity of the cationic Au species present in the catalyst is possible by comparison with the Au (III) standard (-white line intensity, 1.1) and Au (I) standard (-white line intensity, 0.6) reported in the prior literature (see Chang et al, RSC adv.,2014,5, 6912-6918 and Patelouri et al, JACS,1995,117, 11749-11753).

Analysis of the XANES regions for the three Au/C catalysts initially revealed significantly different trailing edge characteristics compared to the metallic Au foil, as shown in fig. 4 b. This supports XRD and STEM analysis, the absence of extended metallic Au structures in fresh catalysts prepared from acetone or aqua regia. The normalized white line heights for fresh samples prepared from acetone and aqua regia indicate that the two catalysts are a mixture of Au (i) and Au (iii), with slightly more Au (i) in the acetone catalyst than the comparative samples prepared using aqua regia based on the lower normalized white line height intensities (Au/C-acetone about 0.66 and Au/C-aqua regia about 0.78). Three different Au standards were used to perform Au L₃Linear fit (LCF) analysis of edge XANES: au (III) (KAuCl)₄/[AuCl₄]^–),Au(I)([AuCl₂]^–) And Au-foil standard spectrum, as shown in fig. 4 c. LCF determines the cationic character of Au in the acetone diffracted catalyst, and Au is predominantly present in the Au (i) oxidation state (77%). This is similar to the behavior of the catalyst prepared using aqua regia, although the distribution of Au (I) - (57%) and Au (III) - (43%) are different.

After 5 hours of use, a small distribution of Au (0) was detectable in the Au/C-acetone catalyst, indicating some instability of the cationic Au species. The reduction of the Au species may be due to deactivation of the catalyst. The stability observed in the acetylene hydrochlorination assay indicates that aggregation occurs during heating up to the reaction temperature and indeed does not occur during the reaction. The extended X-ray absorption fine structure (EXAFS) data for Au/C-acetone and Au/C-aqua regia catalysts (fig. 4d) show that these two catalysts lack long range order and have no characteristic Au-Au distances when compared to the Au foil standard, which is consistent with X-ray diffraction and HAADF-STEM analysis. It was observed in the catalyst used that the increase in the fourier transform intensity of the catalyst used was consistent with the LCF analysis at a distance corresponding to that of the Au foil.

To determine the stability of the Au/C-acetone catalyst, the reaction was extended. At 4 hours after the reaction, the catalyst was cooled to room temperature under Ar gas flow, subsequently sealed for 16 hours, heated under Ar gas flow and tested under test conditions for a further 3 hours. The same test was performed using Au/C-aqua regia material as a comparison. This test is illustrated in fig. 5, which shows good stability of the Au/C-acetone catalyst, maintaining a conversion of 19% to 20% for more than 5 hours, which indicates that the Au oxidation state and dispersion state remain relatively stable after the first 100 minutes of reaction. FIG. 7 shows the XRD pattern of the Au/C-acetone catalyst after 7 hours of reaction compared to the fresh material and the catalyst used for 4 hours. The slight increase in the intrinsic reflectance of the Au nanoparticles after 7 hours of reaction indicates that slow sintering of the catalyst occurs at prolonged reaction times. Also, due to lack of catalyst deactivation, Au (0) may be formed during heating or at the initial stage of the reaction, followed by stabilization. Notably, weak reflections from NaCl can also be observed in the XRD pattern of the catalyst, especially when the synthesis is carried out in ultra-dry solvents. This is due to the inclusion of NaCl in the carbon support, which is prone to recrystallization in the ultra-dry organic solvent, but in the aqueous solvent, it is readily soluble and well dispersed in the catalyst.

In summary, we show that an effective Au/C acetylene hydrochlorination catalyst composed of a monoatomic cationic Au species can be prepared by a simple impregnation method using a low-polarity low-boiling solvent instead of the commonly used strongly acidic and oxidative solvents. These catalysts are comparable in activity and stability to catalysts prepared using aqua regia and have shown structural similarity. Moreover, no significant induction period associated with the rapid evolution of the oxidation state of Au is generally observed in catalysts prepared from strongly oxidizing solvents. This method of preparation facilitates the preparation of single site Au catalysts with relatively high metal loading relative to other reported systems and allows these materials to be fully utilized by eliminating the need to handle highly acidic waste during the catalyst preparation process.

Example 2

Method of producing a composite material

Preparation of the catalyst

All carbon supported catalysts were prepared by the impregnation method described in the article by g.malta et al (Science,2017,355, pages 1399-1403), except that different solvents were used. Firstly, the active carbon (C)ROX 0.8) was ground to obtain powder (150-200 mesh). The precursor was dissolved in acetone (2.7 ml). The precursor solution was added dropwise to the activated carbon and stirred to give a final metal loading of 1 wt% of the catalyst. The obtained powder is heated to a temperature 5-10 deg.C higher than the boiling point of the solvent (acetone) under N₂Drying was carried out under a stream of air for 16 hours. Possibly, a solvent sold as "ultra-dry solvent" sealed in nitrogen is used.

The gold precursor being HAuCl₄.3H₂O (Alfa Aesar,20mg, content 49%).

The ruthenium precursor is Ru (III) (Aldrich) acetylacetonate.

The palladium precursor is Pd (II) (Aldrich) acetylacetonate.

The platinum precursor is 2, 4-pentanedione Pt (II) (Alfa aesar).

Catalyst testing

The catalyst was tested for acetylene hydrochlorination in a fixed bed polyimide (Kapton) microreactor (o.d.6mm, length 20cm) contained within a heating block powered by two heating cartridges inside it. The temperature was controlled by a Eurotherm controller with a type K thermocouple located in the center of the heating block. Using a dehumidifier pair C₂H₂the/Ar (5.01% in Ar, BOC) and HCl/Ar (5.05% in Ar, BOC) gases were dried and then introduced into the reactor. In all cases, the reactor was cleaned with Ar (99.99% BIP, gas product) and then the hydrochlorination mixture was held. The reactor was heated to 180 ℃ at a ramp rate of 5 ℃/min and held at that temperature for 30 minutes, all under a flow of Ar gas (50 ml/min). At a total hourly gas space velocity of 17,600h^-1Mixing C with₂H₂/Ar(23.56ml min^-1),HCl/Ar(23.76ml min^-1) And additional Ar (2.70ml min)^-1) The reaction gas mixture of composition was introduced into a heated reactor chamber containing a catalyst (90mg), maintaining C₂H₂The HCl ratio was constant at 1: 1.02. The gas flow experiment was typically carried out for 240 minutes (4 hours). The gas phase products were analyzed on-line using a Varian450 GC equipped with a Flame Ion Detector (FID). Chromatographic separation and identification of the product was performed using a Porapak N packing column (6 ft. times. 1/8' stainless steel). Under the reaction conditions used, 100% of C₂H₂Conversion produced 35.33mol kg_cat ^-1h^-1The yield of VCM of (1). The experimental error for repeated tests of acetylene conversion was ± 1%.

Catalyst characterization

The powder X-ray diffraction (XRD) pattern was obtained using an X' Pert Pro PAN analysis powder diffractometer operating at 40keV and 40mA with a Cu ka radiation source. The profile was analyzed using X' Pert High Score Plus software.

Au/C, Ru/C, Pt/C and Pd/C catalysts before (fresh) and after 240 minutes (after use) of the reaction were characterized by X-ray absorption Spectroscopy (XAS).

The X-ray absorption spectra (XAS) of all samples were recorded in transmission mode under a B18 Light beam from Diamond Light Source (Harwell, UK). Measurements were performed using a qxafs assembled with a fast scanning Si (111) twin crystal monochromator. The Demeter software package (Athena and Artemis) was used for XAS data analysis of absorption spectra.

At Au L₃Edge (11.92keV), Pt L₃X-ray absorption Spectroscopy (XAS) tests were carried out on the-edge, the Pd K-edge or the Ru K-edge. Except for the corresponding metal precursor (HAuCl)₄,Pt(acac)₂,Pd(acac)₂And Ru (acac)₃) And the X-ray absorption spectra of the fresh catalysts were recorded and analyzed in addition to the metal foils (Au (0), Pt (0), Pd (0), and Ru (0)), and the X-ray absorption near edge structure (XANES) region and the extended X-ray absorption fine structure (EXAFS) region were analyzed.

Materials for detection by Scanning Transmission Electron Microscopy (STEM) were dry dispersed on a porous TEM carbon mesh. These load components were detected in BF-and HAADF-STEM imaging modes of an aberration-corrected JEOL ARM-200CF scanning transmission electron microscope operating at 200 kV. The microscope was also equipped with a Centurio Silicon Drift Detector (SDD) system for X-ray spectroscopy (XEDS).

Results

The results of the tests found that the Au/C, Ru/C, Pt/C, and Pd/C catalysts were active for the production of vinyl chloride monomer (see FIGS. 8-11).

In all cases, the metals in the catalyst (Au, Ru, Pt and Pd) were still cationic but not in the expected metallic form (see fig. 24 to 27, the absence of 2 θ reflections indicating the presence of Au (0) or Ru (0) or Pt (0) or Pd (0)). For the Ru, Pt and Pd catalysts, the ligands around the metal center were observed to be replaced from "acac" to "chlorine". Overall, the catalyst is still a single metal catalyst (see fig. 12-15).

This was confirmed by a scanning electron transmission microscope (STEM). All catalysts contain a monoatomic dispersion of metal (see fig. 16 to 23).

The XANES spectra of the catalysts show overlap with the corresponding metal precursors, but not with the metal foils. Because the metal precursor has an ru (iii), pd (ii), or pt (ii) oxidation state and the metal foil has a (0) oxidation state, the metal in the catalyst has an ru (iii), pd (ii), or pt (ii) oxidation state (see fig. 24 to 30).

The foregoing describes some embodiments of the present invention, but is not intended to limit the invention. Changes and modifications obvious to those skilled in the art are intended to be included within the scope of the present invention, which is defined by the appended claims.