Gold precursor solution with light stability, supported gold catalyst as well as preparation method and application of supported gold catalyst

Abstract

The invention provides a gold precursor solution with light stability, a supported gold catalyst and a preparation method and application of the supported gold catalyst, and the preparation method of the gold precursor solution with light stability comprises the following steps: (1) mixing a strong alkaline solution with a sulfur-containing silane coupling agent, and reacting to obtain a sulfur-containing silane coupling agent hydrolysate; and (2) an aqueous solution of chloroauric acid or / and a chloroauric acid derivative is added into a system obtained after the reaction in the step (1) is completed for a reaction, the gold precursor solution is prepared, and the pH of the sulfur-containing silane coupling agent hydrolysate is larger than or equal to 12.9. The stability of the prepared gold precursor solution containing the sulfur-containing silane coupling agent exceeds 31 days under the illumination condition, and a good foundation is laid for subsequent industrial production of a high-performance supported gold catalyst.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a light-stable gold precursor solution, a supported gold catalyst, and a preparation method and application thereof. Background Art

[0002] When using chloroauric acid as a precursor and adopting an impregnation method to prepare a supported catalyst, the residual chloride ions in the gold precursor will cause the gold catalyst to agglomerate when activated at high temperature, so the prepared catalyst has poor performance. At present, the deposition-precipitation (DP method) method is the most widely used method for preparing supported gold catalysts. When using the DP method to prepare supported gold catalysts, the chloride ions in the gold precursor chloroauric acid are gradually replaced by hydroxide ions, generating a gold species with less chloride ion content and depositing on the surface of the carrier, thereby effectively inhibiting the promotion of chloride ions to the agglomeration of gold particles when activating the supported gold catalyst at high temperature, and finally obtaining a supported gold catalyst with uniform distribution of nano-gold particles. However, the loading efficiency of gold is low when preparing the catalyst by this method, and the catalytic performance is affected by multiple preparation parameters (such as pH, temperature, time, etc.), which brings great challenges to the industrial scale-up production of supported catalysts.

[0003] At present, although the deposition-precipitation method (DPU method) using urea as a precipitant has a high gold loading efficiency, this method is only suitable for carriers with an isoelectric point between 6 and 8, and the performance of the catalyst prepared by this method is still affected by many preparation parameters (such as temperature, aging time, etc.), and many operations such as stirring, washing, and separation are still required during the catalyst preparation process, which also brings huge challenges to the industrial production of supported gold catalysts.

[0004] In addition, whether the DP method or the DPU method using urea as a precipitant is used to prepare the catalyst, the gold precursor formed by the hydrolysis of chloroauric acid is unstable under light conditions and is easily photoreduced to form larger gold particles. Therefore, the catalyst preparation process needs to be kept away from light throughout the process, and the catalyst also needs to be kept away from light during subsequent aging, drying and activation. This poses a huge challenge to the industrial scale-up of high-performance supported gold catalysts.

[0005] Therefore, developing a gold precursor with chloroauric acid and its derivatives as the gold source and having good stability under light conditions, and immobilizing the precursor solution on a carrier by a simple equal volume impregnation method to prepare a highly dispersed gold catalyst, not only helps to overcome the difficulty of light-proof operation required during the preparation of catalysts due to the poor photostability of the precursor solution hydrolyzed by traditional chloroauric acid, but also has the advantages of simple preparation process and high gold loading efficiency, which will provide a good technical practice for the industrial scale-up production of high-performance supported catalysts. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a method for preparing a gold precursor with high stability under light conditions, and the use of the gold precursor in synthesizing a supported gold catalyst and application thereof.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A method for improving the photostability of a gold precursor solution comprises the following steps:

[0009] (1) mixing a strong alkaline solution and a sulfur-containing silane coupling agent, reacting to obtain a sulfur-containing silane coupling agent hydrolyzate;

[0010] (2) adding an aqueous solution of chloroauric acid or / and a chloroauric acid derivative to the system after the reaction in step (1) is completed to react, thereby obtaining the gold precursor solution;

[0011] Wherein, the sulfur-containing silane coupling agent is (R1O)3SiR2S n One or a mixture of two or more of R2(SiOR1)3, (R1O)3SiR2SH, (R1O)3SiR2SR3, wherein R1, R2 and R3 are saturated or unsaturated linear, branched or cyclic alkyl groups with 1 to 15 carbon atoms, and n=2-9; the pH of the hydrolyzate of the sulfur-containing silane coupling agent is ≥12.9.

[0012] The present invention is further configured such that the pH of the hydrolyzate of the sulfur-containing silane coupling agent is ≥13.

[0013] The present invention is further configured such that the strong alkaline solution is selected from any one of tetraethylammonium hydroxide aqueous solution, tetrapropylammonium hydroxide aqueous solution and tetrabutylammonium hydroxide aqueous solution, or a mixed solution of two or more thereof.

[0014] The present invention is further configured that the sulfur-containing silane coupling agent is selected from one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, bis-[3-(triethoxysilyl)propyl]-disulfide or bis-[3-(triethoxysilyl)propyl]-tetrasulfide.

[0015] The present invention is further configured such that in step (2), the general formula of chloroauric acid or chloroauric acid derivatives is MAuCl4, M=H, Na, K or Cs, and the aqueous solution of chloroauric acid or chloroauric acid derivatives is any one of MAuCl4 or a mixed solution of two or more thereof.

[0016] The present invention is further configured such that, in step (1), the reaction conditions are: room temperature, and the time is 6-12 hours. The present invention is further configured such that, in step (2), the reaction conditions are: room temperature, and the time is 0.5-4 hours.

[0017] The present invention is further configured such that the molar ratio of the sulfur-containing silane coupling agent to the chloroauric acid or / and the chloroauric acid derivative is 1.0-15; preferably, the molar ratio of the sulfur-containing silane coupling agent to the chloroauric acid or / and the chloroauric acid derivative is 2.0-10.

[0018] The invention provides a gold precursor solution with photostability prepared according to the method.

[0019] The present invention also provides a method for preparing a supported gold catalyst, comprising the following process: impregnating the light-stable gold precursor solution prepared above on a carrier, and then aging, drying and activating the carrier to obtain the supported gold catalyst; the carrier is selected from at least one of silica, metal oxides, binary or multinary oxides, molecular sieves, carbon materials or MOFs.

[0020] The present invention is further configured that the carrier is selected from one or more of SiO2, CeO2, Al2O3, ZrO2, TiO2-SiO2, calcined or uncalcined TS-1 molecular sieve, calcined or uncalcined TS-2 molecular sieve, calcined or uncalcined Ti-beta molecular sieve, HZSM-5 molecular sieve, SBA-15 molecular sieve, Ti-MCM-41 molecular sieve, Ti-SBA-15 molecular sieve, carbon nanotubes or MOFs.

[0021] The present invention is further configured such that the aging time is 6-24 hours, the aging temperature is 20-35° C.; the drying method is vacuum drying or freeze drying, and the drying time is 12-24 hours.

[0022] The present invention is further configured such that the activation conditions are: high temperature heat treatment in one or a mixture of two or more of hydrogen, oxygen, propane, nitrogen, carbon monoxide, argon, and air, the high temperature heat treatment temperature is 100-550°C, the heating rate is 0.1-5°C / minute, and the heat treatment time is 1-24h.

[0023] The present invention is further configured such that the high temperature heat treatment temperature is 150-500° C., preferably 180-450° C.; the heat treatment time is 1 to 10 hours, more preferably 1 to 5 hours.

[0024] The present invention also provides a supported gold catalyst prepared according to the above preparation method, wherein the gold loading on the supported gold catalyst is 0.005wt%-5.0wt%; preferably, the gold loading on the supported gold catalyst is 0.01wt%-3.0wt%; further preferably, it is 0.05wt% to 0.1wt%.

[0025] The average particle size of the gold particles supported on the prepared supported gold catalyst is 0.5 to 5.0 nm, preferably 1.0 to 3.0 nm, and more preferably 1.0 to 2.0 nm.

[0026] The present invention also provides an application of the above-mentioned supported gold catalyst, wherein the supported gold catalyst is applied to the reaction of preparing acetone by hydrogenation of propane in gas phase or the reaction of preparing propylene oxide by hydrogenation of propylene.

[0027] The present invention is further configured that when the supported catalyst is applied to the reaction of preparing acetone by gas phase hydrogenation of propane or the reaction of preparing propylene oxide by hydrogenation of propylene, when the carrier of the supported catalyst is a carrier without Ti, it is first physically mixed with a titanium-containing material and then used for the reaction of preparing acetone by gas phase hydrogenation of propane or the reaction of preparing propylene oxide by hydrogenation of propylene; the titanium-containing material is selected from at least one of a calcined or uncalcined TS-1 molecular sieve, a calcined or uncalcined TS-2 molecular sieve, a calcined or uncalcined Ti-beta molecular sieve, a Ti-MCM-41 molecular sieve or a Ti-SBA-15 molecular sieve;

[0028] When the carrier of the supported catalyst is a Ti-containing carrier, it is directly applied to the reaction of preparing acetone by hydrogenation of propane in gas phase or the reaction of preparing propylene oxide by hydrogenation of propylene.

[0029] The present invention is further configured that the supported gold catalyst is applied to the reaction of preparing acetone by hydrogenation of propane in gas phase and preparing propylene oxide by hydrogenation of propylene in gas phase, and the reaction conditions are: the space velocity is 3500-56000 mL·h -1 ·g cat -1 , the reaction temperature is 100-250°C, normal pressure. Further, the reaction temperature is 150-220°C.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The prior art requires the use of chloroauric acid hydrolyzed precursors to prepare catalysts in the dark, while the gold precursor solution containing a sulfur-containing silane coupling agent designed and prepared by the present invention is stable for more than 31 days under light conditions, which lays a good foundation for the industrial production of high-performance supported gold catalysts.

[0032] (2) A high-performance supported gold catalyst was synthesized by an equal volume impregnation method using a sulfur-containing silane coupling agent and a gold precursor solution with high stability under light conditions. The catalyst has the advantages of simple process, high gold loading efficiency, good repeatability and high gold dispersion. Its performance in the reaction of propylene hydrogenation to produce propylene oxide and propane hydrogenation to produce acetone is significantly better than that of the catalysts currently prepared by the DPU method and the impregnation method. The stability of the prepared catalyst in the propane hydrogenation reaction exceeds 130 hours, and its performance is significantly better than that of the catalysts currently reported in the literature, showing great prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The gold precursor solution containing the sulfur-containing silane coupling agent prepared in Example 1 is placed under light conditions for different time periods, and from left to right are the states after 0.5 h, 1.0 h, 2.0 h and 31 days respectively;

[0034] Figure 2 The gold precursor solution without sulfur silane coupling agent prepared in Comparative Example 1 is photographed after being placed under light conditions for different time periods, from left to right, respectively, after being protected for 0.5h, 1.0h, 1.5h and 2.0h;

[0035] Figure 3 This is a photograph of the gold precursor solution containing a sulfur-containing silane coupling agent prepared in Comparative Example 2 (placed under light conditions for 2 hours;

[0036] Figure 4 This is a photo of the sulfur-containing silane hydrolyzate prepared in Comparative Example 3;

[0037] Figure 5 This is a photo of the gold precursor containing a sulfur-containing silane coupling agent prepared in Comparative Example 3;

[0038] Figure 6 HAADF-STEM image and particle size distribution diagram of gold nanoparticles on the catalyst prepared in Example 9;

[0039] Figure 7 The HAADF-STEM image and particle size distribution diagram of the gold nanoparticles on the catalyst prepared in Comparative Example 5;

[0040] Figure 8 The HAADF-STEM image and particle size distribution diagram of the gold nanoparticles on the catalyst prepared in Comparative Example 7;

[0041] Fig. 9 The activity results of the catalysts prepared in Example 9, Example 10 and Comparative Example 5 in the reaction of hydrogenation of propane to produce acetone in Example 23 are compared;

[0042] Fig.10The activity results of the catalysts prepared in Example 9 and Comparative Example 7 in the reaction of hydrogenation of propane to produce acetone in Example 23 are compared;

[0043] Fig.11 These are the results of stability evaluation of the catalyst prepared in Example 9 in the reaction of producing acetone from propane hydrogenation. DETAILED DESCRIPTION

[0044] The technical scheme of the present invention is clearly and completely described below in conjunction with specific embodiments. It should be understood that the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of the present invention. The experimental methods in the following embodiments that do not specify specific conditions are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0045] The present invention provides a method for improving the photostability of a gold precursor solution, comprising the following steps:

[0046] (1) mixing a strong alkaline solution and a sulfur-containing silane coupling agent, reacting to obtain a sulfur-containing silane coupling agent hydrolyzate;

[0047] (2) adding an aqueous solution of chloroauric acid or / and a chloroauric acid derivative to the system after the reaction in step (1) is completed to react, thereby obtaining the gold precursor solution;

[0048] The sulfur-containing silane coupling agent is one or a mixture of two or more of (R1O)3SiR2SnR2(SiOR1)3, (R1O)3SiR2SH, (R1O)3SiR2SR3, wherein R1, R2 and R3 are saturated or unsaturated linear, branched or cyclic alkyl groups with 1 to 15 carbon atoms, and n is 2 to 9; the pH of the hydrolyzate of the sulfur-containing silane coupling agent is ≥12.9.

[0049] In an embodiment of the present invention, the pH value of the hydrolyzate of the sulfur-containing silane coupling agent is ≥13, for example, 13, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9 or 14.

[0050] In an embodiment of the present invention, the sulfur-containing silane coupling agent is selected from one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, bis-[3-(triethoxysilyl)propyl]-disulfide or bis-[3-(triethoxysilyl)propyl]-tetrasulfide.

[0051] In an embodiment of the present invention, the strong alkaline solution is selected from any one of tetraethylammonium hydroxide aqueous solution, tetrapropylammonium hydroxide aqueous solution and tetrabutylammonium hydroxide aqueous solution, or a mixed solution of two or more thereof.

[0052] In an embodiment of the present invention, in step (1), the reaction conditions are: room temperature, 6-12 hours. In the present invention, room temperature refers to 20-35°C.

[0053] In an embodiment of the present invention, in step (2), the general formula of the chloroauric acid or chloroauric acid derivative is MAuCl4, M = H, Na, K or Cs, and the aqueous solution of chloroauric acid or its derivative is any one of MAuCl4 and a mixed solution of two or more thereof.

[0054] In an embodiment of the present invention, in step (2), the reaction conditions are: room temperature, 0.5-4h.

[0055] In an embodiment of the present invention, the molar ratio of the sulfur-containing silane coupling agent to chloroauric acid or a chloroauric acid derivative is 1.0-15. Preferably, the molar ratio of the sulfur-containing silane coupling agent to chloroauric acid or a chloroauric acid derivative is 2.0-10, for example, 2.0, 2.7, 3.2, 3.8, 4.2, 4.3, 4.5, 4.8, 5.2, 5.8, 6.2, 7.0, 7.5, 8.0, 8.5, 9.0 or 10.

[0056] The invention provides a gold precursor solution with photostability prepared according to the method.

[0057] The invention provides a method for preparing a supported gold catalyst. The supported gold catalyst is prepared by impregnating a light-stable gold precursor solution on a carrier, and then aging, drying and activating the carrier. The carrier is selected from at least one of silicon dioxide, metal oxides, binary or multinary oxides, molecular sieves, carbon materials or MOFs.

[0058] In an embodiment of the present invention, the carrier is selected from one or more of SiO2, CeO2, Al2O3, ZrO2, TiO2-SiO2, calcined or uncalcined TS-1 molecular sieve, calcined or uncalcined TS-2 molecular sieve, calcined or uncalcined Ti-beta molecular sieve, HZSM-5 molecular sieve, SBA-15 molecular sieve, Ti-MCM-41 molecular sieve, Ti-SBA-15 molecular sieve, carbon nanotubes or MOFs.

[0059] In an embodiment of the present invention, the aging time is 6-24h, and the aging temperature is 20-35°C; the activation conditions are: high-temperature heat treatment in one or a mixture of two or more of hydrogen, oxygen, propane, nitrogen, carbon monoxide, argon, and air, the high-temperature heat treatment temperature is 100-550°C, the heating rate is 0.1-5°C / minute, and the heat treatment time is 1-24h.

[0060] The present invention provides a supported gold catalyst prepared according to the above preparation method, wherein the gold loading amount on the supported gold catalyst is 0.005wt%-5.0wt%; further, the gold loading amount on the supported gold catalyst is 0.01wt%-3.0wt%; further, the gold loading amount on the supported gold catalyst is 0.05wt%-0.10wt%, for example, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt% or 0.10wt%.

[0061] The present invention also provides an application of the supported gold catalyst, which is applied to the reaction of preparing acetone by hydrogenation of propane in gas phase or the reaction of preparing propylene oxide by hydrogenation of propylene.

[0062] In an embodiment of the present invention, when the supported gold catalyst is applied to the reaction of preparing acetone by gas-phase hydrogenation of propane or the reaction of preparing propylene oxide by hydrogenation of propylene, when the carrier of the supported catalyst is a carrier without Ti, it needs to be physically mixed with a titanium-containing material before being used in the reaction of preparing acetone by gas-phase hydrogenation of propane or the reaction of preparing propylene oxide by hydrogenation of propylene; when the carrier of the supported catalyst is a carrier containing Ti, it is directly applied to the reaction of preparing acetone by gas-phase hydrogenation of propane or the reaction of preparing propylene oxide by hydrogenation of propylene.

[0063] In an embodiment of the present invention, the titanium-containing material is selected from at least one of a calcined or uncalcined TS-1 molecular sieve, a calcined or uncalcined TS-2 molecular sieve, a calcined or uncalcined Ti-beta molecular sieve, a Ti-MCM-41 molecular sieve or a Ti-SBA-15 molecular sieve; further, the mass ratio of the supported catalyst to the titanium-containing material is 1:(0.5~1.5).

[0064] In an embodiment of the present invention, the supported gold catalyst is used for the reaction of preparing acetone by gas phase hydrogenation of propane or preparing propylene oxide by hydrogenation of propylene, and the reaction conditions are: the space velocity is 3500-56000 mL·h -1 ·g cat -1 , the reaction temperature is 100-250°C, normal pressure. Preferably, the reaction temperature is 150-220°C.

[0065] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0066] Example 1

[0067] A method for preparing a photostable gold precursor solution comprises the following steps:

[0068] (1) 0.105 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0069] (2) Add 2.12 mL of chloroauric acid aqueous solution (concentration: 1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent.

[0070] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp to observe the light stability of the gold precursor solution. Figure 1 As shown, the gold precursor solution containing the sulfur-containing silane coupling agent prepared in Example 1 remains clear and transparent after being exposed to a fluorescent lamp for 31 days, and has good stability. It can still remain clear and transparent even after being exposed to a fluorescent lamp for 100 days.

[0071] Example 2

[0072] A method for preparing a photostable gold precursor solution comprises the following steps:

[0073] (1) 0.063 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0074] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions.

[0075] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp and allowed to stand. The results showed that the photostability of the prepared gold precursor solution exceeded 31 days.

[0076] Example 3

[0077] A method for preparing a photostable gold precursor solution comprises the following steps:

[0078] (1) 0.147 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0079] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions.

[0080] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp and allowed to stand. The results showed that the photostability of the prepared gold precursor solution exceeded 31 days.

[0081] Example 4

[0082] A method for preparing a photostable gold precursor solution comprises the following steps:

[0083] (1) 0.210 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, and the mixture was mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0084] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions.

[0085] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp and allowed to stand. The results showed that the photostability of the prepared gold precursor solution was more than 31 days.

[0086] Example 5

[0087] A method for preparing a photostable gold precursor solution comprises the following steps:

[0088] (1) 0.128 g of (3-mercaptopropyl)triethoxysilane was added to a beaker, and then 4.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0089] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions.

[0090] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp and allowed to stand. The results showed that the photostability of the prepared gold precursor solution was more than 31 days.

[0091] Example 6

[0092] A method for preparing a photostable gold precursor solution comprises the following steps:

[0093] (1) 0.105 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 mL of tetraethylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.1.

[0094] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions.

[0095] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp and allowed to stand. The results showed that the photostability of the prepared gold precursor solution was more than 31 days.

[0096] Example 7

[0097] A method for preparing a photostable gold precursor solution comprises the following steps:

[0098] (1) 0.053 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 ml of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0099] (2) 1.06 ml of chloroauric acid aqueous solution (1 g / 50 ml) was added to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mixed and stirred at 30° C. for 1 hour to obtain a gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions.

[0100] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp and allowed to stand. The results showed that the photostability of the prepared gold precursor solution was more than 31 days.

[0101] Example 8

[0102] A method for preparing a photostable gold precursor solution comprises the following steps:

[0103] (1) 0.105 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0104] (2) Add 2.12 mL of potassium chloroaurate aqueous solution (1.20 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent.

[0105] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp to observe the light stability of the gold precursor solution. The results showed that the obtained gold precursor solution containing the sulfur-containing silane coupling agent remained clear and transparent after being exposed to the fluorescent lamp for 31 days, and had good stability.

[0106] Comparative Example 1

[0107] A method for preparing a gold precursor solution specifically comprises the following steps:

[0108] (1) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) into a beaker containing 4.5 mL of tetrapropylammonium hydroxide solution, mix and stir at 30° C. for 1 h to obtain a gold precursor solution.

[0109] The obtained gold precursor solution was placed under a fluorescent lamp to observe the light stability of the gold precursor solution prepared in Comparative Example 1. Figure 2 As shown, after the gold precursor solution prepared in Comparative Example 1 was exposed to fluorescent light for 1 hour, the gold precursor solution became obviously turbid and formed obvious black precipitate, and the stability was very poor.

[0110] Comparative Example 2

[0111] A method for preparing a gold precursor solution comprises the following steps:

[0112] (1) 0.021 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 4.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 13.0.

[0113] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent.

[0114] The gold precursor solution obtained in step (2) was placed under a fluorescent lamp to observe the light stability of the gold precursor solution obtained in Comparative Example 2. Figure 3 As shown, after the gold precursor solution prepared in Comparative Example 2 was exposed to fluorescent light for 2 hours, a small amount of black precipitate appeared in the gold precursor solution, and the stability was very poor.

[0115] Comparative Example 3

[0116] A method for preparing a gold precursor solution comprises the following steps:

[0117] (1) 0.105 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 1.125 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, and the mixture was mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 10.3.

[0118] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent.

[0119] However, in step (1), a large amount of white silica floccules precipitate in the obtained sulfur-containing silane hydrolyzate. Figure 4 As shown; in step (2), after adding chloroauric acid, more white silica floccules precipitate and the solution color is yellow. The result is as follows Figure 5 shown.

[0120] Comparative Example 4

[0121] A method for preparing a gold precursor solution comprises the following steps:

[0122] (1) 0.105 g of (3-mercaptopropyl)trimethoxysilane was added to a beaker, and then 2.5 mL of tetrapropylammonium hydroxide solution was added dropwise to the beaker, mixed and stirred at 30° C. for 10 h to obtain a sulfur-containing silane coupling agent hydrolyzate. The pH of the sulfur-containing silane coupling agent hydrolyzate was measured to be 12.6.

[0123] (2) Add 2.12 mL of chloroauric acid aqueous solution (1 g / 50 mL) to the above-mentioned sulfur-containing silane coupling agent hydrolyzate, mix and stir at 30° C. for 1 h to obtain a gold precursor solution containing a sulfur-containing silane coupling agent.

[0124] After adding chloroauric acid to the sulfur-containing silane hydrolyzate obtained in step (1) and hydrolyzing for 1 hour, the monomers formed by hydrolysis in step (1) agglomerate to form a large amount of white silica flocculent precipitate.

[0125] Example 9

[0126] A method for preparing a supported gold catalyst comprises the following steps:

[0127] (1) The gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions obtained by the method described in Example 1 was diluted to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.39 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0128] (2) The solid powder obtained in step (1) was sieved with a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading is shown in Table 1. The HAADF-STEM image and particle size distribution of the nano-gold particles on the gold catalyst are shown in Table 1. Figure 6 As shown, the average particle size of the nano-gold particles is about 1.7±0.5 nm, and the nano-gold particles have good dispersion.

[0129] Example 10

[0130] A method for preparing a supported gold catalyst comprises the following steps:

[0131] (1) The gold precursor solution containing a sulfur-containing silane coupling agent and having high stability under light conditions obtained by the method described in Example 1 was placed under a fluorescent lamp for 31 days, and then the volume was adjusted to 10 mL. 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.39 mL of the above gold precursor solution was added dropwise while stirring. After aging at 30° C. for 12 h in a constant temperature oven, the mixture was vacuum dried at room temperature for 12 h.

[0132] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was increased from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading is shown in Table 1.

[0133] Examples 11 to 15

[0134] A method for preparing a supported gold catalyst, wherein Examples 11 to 15 are respectively prepared using the gold precursor solutions containing sulfur-containing silane coupling agents prepared in Examples 2 to 6 to prepare supported gold catalysts, specifically comprising the following steps:

[0135] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the methods described in Examples 2 to 6 was fixed to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.39 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0136] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was increased from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading is shown in Table 1.

[0137] Example 16

[0138] A method for preparing a supported gold catalyst specifically comprises the following steps:

[0139] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the method described in Example 1 was fixed to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.55 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0140] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor, into which a hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading in the prepared gold catalyst was 0.10 wt%.

[0141] Embodiment 17

[0142] A method for preparing a supported gold catalyst specifically comprises the following steps:

[0143] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the method described in Example 7 was fixed to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.55 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0144] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor, into which a hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading in the prepared supported gold catalyst was 0.05 wt%.

[0145] Embodiment 18

[0146] A method for preparing a supported gold catalyst specifically comprises the following steps:

[0147] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the method described in Example 1 was fixed to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.55 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0148] (2) The solid powder obtained in step (1) was sieved with a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor, into which a hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 350°C at a rate of 1.5°C / min for 1.5 h to obtain a supported gold catalyst. The gold loading in the supported gold catalyst was 0.10 wt%.

[0149] Embodiment 19

[0150] A method for preparing a supported gold catalyst specifically comprises the following steps:

[0151] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the method described in Example 8 was fixed to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.44 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0152] (2) The solid powder obtained in step (1) was sieved with a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor, into which a hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading in the prepared gold catalyst was 0.08 wt%.

[0153] Embodiment 20

[0154] A method for preparing a supported gold catalyst specifically comprises the following steps:

[0155] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the method described in Example 1 was fixed to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-2-B was weighed into a 30 mL glass beaker, and then 0.55 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0156] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor, into which a hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading in the prepared gold catalyst was 0.10 wt%.

[0157] Embodiment 21

[0158] A method for preparing a supported gold catalyst specifically comprises the following steps:

[0159] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the method described in Example 1 was fixed to 10 mL, 1.0 g of SiO2 was weighed into a 30 mL glass beaker, and then 0.55 mL of the above gold precursor solution was added dropwise while stirring. The mixture was then aged at 30° C. for 12 h in a constant temperature oven and then vacuum dried at room temperature for 12 h.

[0160] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor, into which a hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading in the prepared gold catalyst was 0.10 wt%.

[0161] Embodiment 22

[0162] A method for preparing a supported gold catalyst specifically comprises the following steps:

[0163] (1) The gold precursor solution containing the sulfur-containing silane coupling agent obtained by the method described in Example 1 was fixed to 10 mL, 1.0 g of ZrO2 was weighed into a 30 mL glass beaker, and then 0.55 mL of the above gold precursor solution was added dropwise while stirring. The mixture was then aged at 30° C. for 12 h in a constant temperature oven and then vacuum dried at room temperature for 12 h.

[0164] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor, into which a hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading in the prepared gold catalyst was 0.10 wt%.

[0165] Comparative Example 5

[0166] A preparation method of a supported gold catalyst comprises the following steps:

[0167] (1) The gold precursor solution obtained by the method described in Comparative Example 1 was allowed to stand for 2 h under a fluorescent lamp, then the volume was adjusted to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.39 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0168] (2) The solid powder obtained in step (1) was sieved with a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading is shown in Table 1. The HAADF-STEM image and particle size distribution of the nano-gold particles on the gold catalyst are shown in Table 1. Figure 7 As shown, there are no gold particles with a particle size less than 2 nm on the catalyst, and the average particle size of the nano-gold particles is about 5.5±0.7 nm.

[0169] Comparative Example 6

[0170] A preparation method of a supported gold catalyst comprises the following steps:

[0171] (1) The gold precursor solution obtained by the method described in Comparative Example 2 was allowed to stand for 2 h under a fluorescent lamp, then the volume was adjusted to 10 mL, 1.0 g of uncalcined titanium silicon molecular sieve TS-1-B was weighed into a 30 mL glass beaker, and then 0.39 mL of the above gold precursor solution was added dropwise while stirring, and then aged at 30° C. in a constant temperature oven for 12 h and then vacuum dried at room temperature for 12 h.

[0172] (2) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was increased from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a supported gold catalyst. The gold loading is shown in Table 1.

[0173] Comparative Example 7

[0174] The gold catalyst immobilized on the uncalcined titanium silicalite TS-1-B was prepared by a deposition-precipitation method using urea as a precipitant, and the steps are as follows:

[0175] (1) First, add 39 mL of water into a 100 mL beaker, and then place the beaker in a constant temperature water bath with magnetic stirring. Then, add 0.78 mL of chloroauric acid aqueous solution (1 g / 50 mL), 0.0705 g of urea, and 1.0 g of uncalcined titanium silicalite TS-1-B into the beaker in sequence. Then, heat the mixture from room temperature to 90 °C in a dark environment and stir for 6 h.

[0176] (2) The slurry obtained in step (1) was placed in a 50 mL centrifuge tube, centrifuged at 8000 r / min for 10 minutes, then 40 mL of water was added for washing and centrifuged again at 8000 r / min for 10 minutes. The solid obtained by centrifugation was vacuum dried at room temperature for 12 h.

[0177] (3) The solid powder obtained in step (2) was sieved with a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was raised from room temperature to 300°C at a rate of 1.5°C / min for 1.5 h to obtain a gold catalyst. The gold loading is shown in Table 1. The HAADF-STEM image and particle size distribution of the gold nanoparticles on the gold catalyst are shown in Figure 8 As shown, the average particle size of the gold nanoparticles is about 2.1±0.5 nm.

[0178] Comparative Example 8

[0179] The gold catalyst immobilized on the uncalcined titanium silicalite TS-1-B was prepared by a deposition-precipitation method using urea as a precipitant, and the steps are as follows:

[0180] (1) First, add 39 mL of water into a 100 mL beaker, and then place the beaker in a constant temperature water bath with magnetic stirring. Then, add 1.10 mL of chloroauric acid aqueous solution (1 g / 50 mL), 0.0705 g of urea, and 1.0 g of uncalcined titanium silicalite TS-1-B into the beaker in sequence. Then, heat the mixture from room temperature to 90 °C in a dark environment and stir for 6 h.

[0181] (2) The slurry obtained in step (1) was placed in a 50 mL centrifuge tube, centrifuged at 8000 r / min for 10 minutes, then 40 mL of water was added for washing and centrifuged again at 8000 r / min for 10 minutes. The solid obtained by centrifugation was vacuum dried at room temperature for 12 h.

[0182] (3) The solid powder obtained in step (2) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was increased from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a gold catalyst. The gold loading is shown in Table 3.

[0183] Comparative Example 9

[0184] The ZrO2-immobilized gold catalyst was prepared by a deposition-precipitation method using urea as a precipitant, and the steps are as follows:

[0185] (1) First, add 39 mL of water into a 100 mL beaker, and then place the beaker in a constant temperature water bath with magnetic stirring. Then, add 1.10 mL of chloroauric acid aqueous solution (1 g / 50 mL), 0.09 g of urea, and 1.0 g of ZrO2 into the beaker in sequence. Then, heat the mixture from room temperature to 90 °C in the dark and stir for 6 h.

[0186] (2) The slurry obtained in step (1) was placed in a 50 mL centrifuge tube, centrifuged at 8000 r / min for 10 minutes, then 40 mL of water was added for washing and centrifuged again at 8000 r / min for 10 minutes. The solid obtained by centrifugation was vacuum dried at room temperature for 12 h.

[0187] (3) The solid powder obtained in step (1) was sieved through a 100-mesh sieve, and 0.15 g was weighed and loaded into a fixed bed reactor. A hydrogen / nitrogen mixed gas (36% H2) was introduced, and then the temperature was increased from room temperature to 300°C at a rate of 1.5°C / min for reduction for 1.5 h to obtain a gold catalyst. The gold loading is shown in Table 4.

[0188] Embodiment 23

[0189] Catalyst performance evaluation

[0190] The catalytic performance of the gold catalysts prepared in Examples 9 to 20 and Comparative Examples 3 and 4 was evaluated in the propane gas phase hydrogenation reaction to prepare acetone. The propane gas phase hydrogenation reaction was carried out in a fixed bed reactor at atmospheric pressure, and the reaction atmosphere composition was propane: hydrogen: oxygen: nitrogen = 1:1:1:7 (volume ratio), and the space velocity was 14000 mL·h -1 ·g cat -1 The reaction temperature was 200°C, and the outlet product was analyzed by gas chromatography. The catalytic results are shown in Table 1.

[0191] Table 1 Performance evaluation of catalysts for the reaction of propane gas phase hydrogenation to produce acetone

[0192]

[0193]

[0194] From the results of the performance evaluation of the gold catalysts prepared by the comparative examples 9-10 and comparative examples 5-7, it can be seen that the performance of the catalyst prepared by the gold precursor containing sulfur-containing silane coupling agent prepared by the preparation method of the present invention after exposure to fluorescent lamps for 31 days is similar to that of the catalyst synthesized by the freshly prepared gold precursor containing sulfur-containing silane coupling agent, while the stability of the gold precursor containing no sulfur-containing silane coupling agent is poor, and the activity of the catalyst prepared by the precursor is low. The above results show that the gold precursor containing sulfur-containing silane coupling agent prepared by the present invention is superior to having good light stability, and even if exposed to light conditions, the gold precursor can be fixed on the carrier by a simple equal volume impregnation method to prepare a high-performance supported gold catalyst, which breaks through the difficulty of the current use of gold precursors hydrolyzed by chloroauric acid to prepare catalysts, which requires light-proof operation, thereby laying a good foundation for the industrial scale-up production of supported gold catalysts.

[0195] Combination Figure 6 , 8 10 and the results of Example 9 and Comparative Example 7 shown in Table 1 show that the catalyst prepared by the equal volume impregnation method using the gold precursor containing the sulfur-containing silane coupling agent prepared by the present invention and having good stability under light conditions has a significantly better acetone generation rate in the propane hydrogenation to acetone reaction than the catalyst prepared by the conventional deposition-precipitation method using urea as a precipitant; at the same time, according to Figure 6 and Figure 8 As shown in the catalyst particle size distribution diagram, the dispersion of the nano-gold particles on the catalyst prepared by the equal volume impregnation method using the gold precursor containing sulfur-containing silane coupling agent prepared by the present invention and having good stability under light conditions is significantly higher than that of the catalyst prepared by the traditional deposition-precipitation method using urea as a precipitant, while the particle size of the nano-gold particles on the catalyst prepared by the gold precursor without sulfur-containing silane is significantly larger (e.g. Figure 7 The above results show that the dispersion degree and catalytic performance of the nano-gold particles on the supported gold catalyst prepared by a simple equal volume impregnation method using the gold precursor containing a sulfur-containing silane coupling agent prepared by the present invention and having excellent stability under light conditions are significantly better than those of the traditional supported gold catalyst prepared by a deposition-precipitation method using urea as a precipitant, which also provides important support for the industrial production of high-performance supported gold catalysts with highly dispersed nano-gold particles.

[0196] Embodiment 24

[0197] Catalyst performance evaluation

[0198] The catalytic performance of the gold catalyst prepared in Example 9 was evaluated in the propane gas phase hydrogenation reaction to prepare acetone. The propane gas phase hydrogenation reaction was carried out in a fixed bed reactor at normal pressure, and the reaction atmosphere composition was propane: hydrogen: oxygen: nitrogen = 3:1:1:5 (volume ratio), and the space velocity was 14000 mL·h -1 ·g cat -1 The reaction temperature was 180°C, and the outlet product was analyzed by gas chromatography. The catalytic results are shown in Table 2. The trend of acetone generation rate with reaction time is shown in Fig.11 As shown, according to Fig.11 The results show that the catalyst prepared by the present invention still exhibits excellent catalytic activity after long-term operation, that is, the gold catalyst has excellent stability.

[0199] Table 2 Performance evaluation of catalysts for the reaction of propane gas phase hydrogenation to produce acetone

[0200]

[0201] Embodiment 25

[0202] Catalyst performance evaluation

[0203] The catalysts prepared in Example 10 and Comparative Example 8 were used to evaluate the catalytic performance in the reaction of preparing propylene oxide by gas phase hydrogenation of propylene. The gas phase hydrogenation of propylene was carried out in a fixed bed reactor at atmospheric pressure. The reaction atmosphere was composed of propylene: hydrogen: oxygen: nitrogen = 1:1:1:7 (volume ratio), and the space velocity was 14000 mL·h -1 ·g cat -1 The reaction temperature was 200°C, and the outlet product was analyzed by gas chromatography. The catalytic results are shown in Table 3.

[0204] Table 3 Performance evaluation of catalysts for gas phase hydrogenation of propylene to produce propylene oxide

[0205]

[0206] According to the comparison of the performance evaluation results of the catalysts prepared in Example 10 and Comparative Example 8 in the reaction of propylene hydrogenation to produce propylene oxide, it can be seen that the propylene oxide generation rate on the supported gold catalyst prepared by a simple equal volume impregnation method using the gold precursor containing a sulfur-containing silane coupling agent prepared by the present invention is much higher than that of the supported gold catalyst prepared by the traditional deposition-precipitation method using urea as a precipitant; this further illustrates that the method developed by the present invention of fixing the gold precursor containing a sulfur-containing silane coupling agent on a carrier by an equal volume impregnation method is indeed an effective method for preparing a high-performance supported gold catalyst.

[0207] Embodiment 26

[0208] 0.075 g of the catalysts prepared in Example 21, Example 22 and Comparative Example 9 were respectively mixed with 0.075 g of uncalcined TS-1-B and then their catalytic performance in the preparation of propylene oxide by gas phase hydrogenation of propylene was evaluated. The gas phase hydrogenation of propylene was carried out in a fixed bed reactor at atmospheric pressure. The reaction atmosphere was composed of propylene: hydrogen: oxygen: nitrogen = 1:1:1:7 (volume ratio), and the space velocity was 14000 mL·h -1 ·g cat -1 The reaction temperature was 200°C, and the outlet product was analyzed by gas chromatography. The catalytic results are shown in Table 4.

[0209] Table 4 Catalyst performance evaluation

[0210]

[0211] According to the performance evaluation results of the catalysts prepared in Examples 21-22 and Comparative Example 9 in the reaction of propylene hydrogenation to produce propylene oxide, it can be seen that the gold precursor prepared by the present invention containing a sulfur-containing silane coupling agent and having excellent stability under light conditions can be used to fix gold on SiO2 and ZrO2 by a simple isovolumetric impregnation method to prepare a high-performance supported gold catalyst. The results show that the use of a gold precursor containing a sulfur-containing silane coupling agent and having excellent stability under light conditions to prepare a supported gold catalyst by a simple isovolumetric impregnation method has the characteristics of strong carrier applicability, which breaks through the traditional use of urea as a precipitant and the requirement that the isoelectric point of the carrier is 6-8 when preparing the catalyst by the deposition-precipitation method, expands the carrier adaptation range of the supported gold catalyst, and further shows that the method developed by the present invention to fix the gold precursor containing a sulfur-containing silane coupling agent on the carrier by the isovolumetric impregnation method is an effective method for preparing a high-performance supported gold catalyst.

[0212] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the photostability of a gold precursor solution, characterized in that: The steps include: (1) mixing a strong alkaline solution and a sulfur-containing silane coupling agent, reacting to obtain a sulfur-containing silane coupling agent hydrolyzate; (2) adding an aqueous solution of chloroauric acid or / and a chloroauric acid derivative to the system after the reaction in step (1) is completed to react, thereby obtaining the gold precursor solution; The sulfur-containing silane coupling agent is (R1O)3SiR2S n One or a mixture of two or more of R2(SiOR1)3, (R1O)3SiR2SH, (R1O)3SiR2SR3, wherein R1, R2 and R3 are saturated or unsaturated linear, branched or cyclic alkyl groups with 1 to 15 carbon atoms, and n=2-9; the pH of the hydrolyzate of the sulfur-containing silane coupling agent is ≥12.

9.

2. A method for improving the photostability of a gold precursor solution according to claim 1, characterized in that: In step (1), the strong alkaline solution is selected from any one of tetraethylammonium hydroxide aqueous solution, tetrapropylammonium hydroxide aqueous solution and tetrabutylammonium hydroxide aqueous solution, or a mixed solution of two or more thereof.

3. A method for improving the photostability of a gold precursor solution according to claim 1, characterized in that: In step (1), the sulfur-containing silane coupling agent is selected from one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, bis-[3-(triethoxysilyl)propyl]-disulfide or bis-[3-(triethoxysilyl)propyl]-tetrasulfide; In step (2), the general formula of chloroauric acid or chloroauric acid derivatives is MAuCl4, M = H, Na, K or Cs, and the aqueous solution of chloroauric acid or chloroauric acid derivatives is any one of MAuCl4 or a mixed solution of two or more thereof.

4. The method for improving the photostability of a gold precursor solution according to claim 1, characterized in that: In step (1), the reaction conditions are: room temperature, time is 6-12h; in step (2), the reaction conditions are: room temperature, time is 0.5-4h.

5. The method for improving the photostability of a gold precursor solution according to claim 1, characterized in that: The molar ratio of the sulfur-containing silane coupling agent to chloroauric acid or / and chloroauric acid derivatives is 1.0-15.

6. A photostable gold precursor solution prepared according to the method of any one of claims 1 to 5.

7. A method for preparing a supported gold catalyst, characterized in that: The method comprises the following steps: impregnating the light-stable gold precursor solution of claim 6 on a carrier, and preparing the supported gold catalyst after aging, drying and activation; the carrier is selected from at least one of silicon dioxide, metal oxides, binary or multinary oxides, molecular sieves, carbon materials or MOFs; Preferably, the carrier is selected from one or more of SiO2, CeO2, Al2O3, ZrO2, TiO2-SiO2, calcined or uncalcined TS-1 molecular sieve, calcined or uncalcined TS-2 molecular sieve, calcined or uncalcined Ti-beta molecular sieve, HZSM-5 molecular sieve, SBA-15 molecular sieve, Ti-MCM-41 molecular sieve, Ti-SBA-15 molecular sieve, carbon nanotubes or MOFs.

8. The method for preparing a supported gold catalyst according to claim 7, characterized in that: The aging time is 6-24 hours, the aging temperature is 20-35°C; the drying method is vacuum drying or freeze drying, and the drying time is 12-24 hours; The activation conditions are: high-temperature heat treatment in one or a mixture of two or more of hydrogen, oxygen, propane, nitrogen, carbon monoxide, argon, and air, the high-temperature heat treatment temperature is 100-550°C, the heating rate is 0.1-5°C / min, and the heat treatment time is 1-24h.

9. A supported gold catalyst prepared according to the preparation method of claim 7 or 8, characterized in that: The gold loading on the supported gold catalyst is 0.005 wt % to 5.0 wt %.

10. Use of the supported gold catalyst as claimed in claim 9, in the reaction of producing acetone by gas phase hydrogenation of propane or producing propylene oxide by hydrogenation of propylene.

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