CN103894227B - The preparation method of the Au catalyst of preparing epoxypropane by epoxidation of propene - Google Patents

Abstract

The invention discloses a preparation method of a gold catalyst for preparing propylene oxide by epoxidation of propylene, relating to the gold catalyst. 1) Dried the leaves of the plant orientalis and crushed them to obtain dry powder of the leaves of the plants, then added them to water, oscillated, and filtered to obtain the plant biomass leaching solution; 2) Added titanium silicon molecular sieve and gold precursor chloroauric acid ( HAuCl ₄ ) aqueous solution and ionic liquid [Bpy][N(CN) ₂ ] to obtain solution A; 3) adding the plant biomass leachate obtained in step 1) to solution A obtained in step 2) to obtain solution B; 4 ) The solution B obtained in step 3) is suction-filtered, washed, dried, and activated to obtain a gold catalyst for the preparation of propylene oxide by epoxidation of propylene, and the gold catalyst for the preparation of propylene oxide by epoxidation of propylene is a powdery supported type gold catalyst. It has the advantages of low cost, green environmental protection and the like. The prepared catalyst is used to catalyze the epoxidation of propylene, and has the advantages of good activity, high stability and the like.

Description

Preparation method of gold catalyst for propylene oxide preparation of propylene oxide

technical field

The invention relates to a gold catalyst, in particular to a preparation method of a gold catalyst for preparing propylene oxide by epoxidation of propylene.

Background technique

Propylene oxide (referred to as PO) is the third largest organic chemical product in the propylene derivatives after polypropylene and acrylonitrile. It is mainly used in the production of polyether polyols, as well as surfactants, propylene carbonate and propylene glycol ( PG) etc. In 2012, the annual production capacity of PO in the world has exceeded 9.54 million tons, among which Asia is the region with the fastest growth in production capacity, and the demand in China and the Middle East has the fastest growth. At the end of 2012, the annual production capacity of PO in China has reached 1.88 million tons. It is expected that by 2015 my country's demand for propylene oxide is expected to reach about 2.84 million tons (China Petroleum and Chemical Economic Analysis 2013, 6, 51-53). At present, the main production processes for producing PO in industry include chlorohydrin method, co-oxidation method and H ₂ O ₂ liquid phase oxidation method. The chlorohydrin method has a short process and less construction investment, but produces a large amount of waste water and waste residue, which seriously pollutes the environment. Must be dealt with. The co-oxidation method overcomes the environmental pollution and equipment corrosion problems of the chlorohydrin method, but the process is long, the investment cost is high, and its economy is restricted by a large number of co-products (IndEnChemRes, 2006, 45, 3447-3459). The H ₂ O ₂ liquid-phase oxidation method faces the problems of high preparation cost and inconvenient use of H ₂ O ₂ (JMolCatala-Chem1997, 117, 351-356).

In 1998, Haruta et al. found that the Au/TiO ₂ catalyst prepared by the deposition-precipitation (DP) method could directly catalyze the direct gas-phase epoxidation of propylene under the atmosphere of H ₂ and O ₂ and a milder reaction temperature (JCatal, 1998, 178 , 566-575), the resulting PO selectivity exceeds 90%. The preparation method is relatively simple and is a new way to prepare propylene oxide. However, the utilization rate of gold in the DP method is very low, usually less than 2% of the gold is deposited on the catalyst support (JCatal, 2004, 226, 156-170), although the activity and selectivity of the gold catalyst prepared by this method are relatively high , but its stability needs to be improved. The bioreduction method is also a new method to prepare gold catalyst for propylene epoxidation (CatalCommun2011, 12, 830-833). The catalyst prepared by this method has high catalytic stability, but the catalytic reaction temperature is high. Based on this Similar problems exist in the bioreduction ionic liquid-assisted loading method proposed above (JCatal 2011, 283, 192-201).

Contents of the invention

The purpose of the present invention is to provide a method for preparing a gold catalyst for the preparation of propylene oxide by epoxidation of propylene, which has the advantages of low cost, environmental protection and the like.

The present invention comprises the following steps:

1) Dried the leaves of the plant orientalis and pulverized them to obtain the dry powder of the leaves of the plants, and then added them into water, oscillated, and filtered to obtain the plant biomass extract;

2) Add titanium silicon molecular sieve, gold precursor chloroauric acid (HAuCl ₄ ) aqueous solution and ionic liquid [Bpy][N(CN) ₂ ] into water to obtain solution A;

3) adding the plant biomass leaching solution obtained in step 1) to the solution A obtained in step 2) to obtain solution B;

4) Suction filter the solution B obtained in step 3), wash, dry, and activate to obtain a gold catalyst for the preparation of propylene oxide by epoxidation of propylene, and the obtained gold catalyst for the preparation of propylene oxide by epoxidation of propylene is supported in powder form type gold catalyst.

In step 1), the ratio of the plant orientalis leaf dry powder to water can be 10g: 1L, wherein the plant orientalis leaf dry powder is calculated by mass, and the water is calculated by volume; the water can be deionized water, so The oscillation can be placed in a shaker for 2 hours.

In step 2), the ratio of water, titanium-silicon molecular sieve, and ionic liquid [Bpy][N(CN) ₂ ] can be 50mL: 0.5g: (0-300) μL, wherein water and ionic liquid [Bpy ][N(CN) ₂ ] is calculated by volume, and titanium silicon molecular sieve is calculated by mass.

In step 3), the ratio of the added amount of the plant biomass leaching solution to the water in step 1) may be 50mL: 1L.

In step 4), the washing can be washed with deionized water, the drying can be dried under vacuum at 50°C for 24 hours, and the activation can be activated at 375°C for 6 hours; the obtained propylene is epoxidized to prepare propylene oxide The loading amount of gold in the gold catalyst is 0.25%-4.0%.

The propylene catalyzed epoxidation reaction is carried out in an atmospheric fixed-bed reaction device. The reaction gas composition is C ₃ H ₆ /H ₂ /O ₂ /N ₂ =1/1/1/7 (volume ratio), the space velocity is 7000mL·h ^-1 ·g ^-1 _cat , and the reaction temperature is 220～300℃ , The reaction products were detected and analyzed by gas chromatography FID and TCD.

In the present invention, the chloroauric acid water, the titanium silicon molecular sieve and the ionic liquid are first mixed, and the Au(III) ion and the ionic liquid are complexed and loaded on the surface of the carrier, and then the protective effect of the plant biomass extract is used to prevent the catalyst from being roasted. Agglomeration of gold nanoparticles occurs during the process, and the supported gold catalyst prepared by this method has high activity and has a good application prospect.

The invention proposes a new method for preparing a propylene epoxidation gold catalyst, which is different from the traditional DP method, biological reduction method and biological reduction ionic liquid auxiliary loading method. First, Au(III) ions are loaded onto the surface of the carrier in the presence of ionic liquid [Bpy][N(CN) ₂ ], then plant biomass extract is added, and finally the catalyst is prepared under a certain atmosphere. This method is quite different from the DP method. In the DP method, ionic liquid and plant matter are not introduced, while Au nanoparticles are obtained by plant matter reduction in the bioreduction method and the bioreduction ionic liquid auxiliary loading method. In the present invention, the Au nanoparticle It is obtained by roasting, and the ionic liquid [Bpy][N(CN) ₂ ] plays the role of complexing with Au(III) ions, rather than the role of auxiliary loading. The method proposed by the invention has the advantages of low cost, environmental protection and the like. The prepared catalyst is used to catalyze the epoxidation of propylene, and has the advantages of good activity, high stability and the like.

Description of drawings

Figure 1 is a transmission electron microscope TEM image of a gold catalyst for the preparation of propylene oxide by epoxidation of propylene in Example 1 of the present invention. The scale bar in the figure is 50nm.

Fig. 2 is a transmission electron microscope TEM image of a gold catalyst for preparing propylene oxide by epoxidation of propylene obtained in Example 2 of the present invention. The scale bar in the figure is 50nm.

detailed description

Below by embodiment the present invention will be further described.

Example 1

Preparation of plant biomass leaching solution: Take 5g of Arborvitae leaf dry powder in a conical flask, add 500mL of deionized water, put it in a constant temperature water bath shaker (30°C, 150r/min) and shake for 2h, filter and dilute the filtrate to 500mL, the concentration is set at 10g/L plant biomass leachate.

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 150μL of ionic liquid [Bpy][N(CN) ₂ ], and stir Suction filtration was carried out after 1h, and washed with 500mL deionized water, dried under vacuum at 50°C for 24h, and activated under air atmosphere at 375°C for 6h to obtain a powdery supported gold catalyst, which was obtained in Example 1 to prepare propylene oxide by epoxidation of propylene The transmission electron microscope TEM image of the gold catalyst is shown in Figure 1.

Add 0.15g of Catalyst A to the atmospheric fixed bed micro reaction device, the reaction gas composition is C ₃ H ₆ /H ₂ /O ₂ /N ₂ =1/1/1/7 (volume ratio), and the space velocity is 4000mL· h ^-1 ·g ^-1 _cat , the reaction temperature is 300°C, and the results of the catalytic reaction are shown in Table 1.

Example 2

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 150μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1 hour, add 50 mL of the leach solution in Example 1, continue to stir for 1 hour, then filter with suction, wash with 500 mL of deionized water, dry under vacuum at 50°C for 24 hours, and activate under air atmosphere at 375°C for 6 hours to obtain a powdery supported gold catalyst. Catalyst evaluation conditions are the same as in Example 1, and the catalytic reaction results are shown in Table 1. Embodiment 2 makes propylene epoxidation and prepares the transmission electron microscope TEM figure of the gold catalyst of propylene oxide referring to Fig. 2.

Example 3

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 50μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1 hour, add 50 mL of the leach solution in Example 1, continue stirring for 1 hour, filter with suction, wash with 500 mL of deionized water, dry under vacuum at 50°C for 24 hours, and activate under air atmosphere at 375°C for 6 hours to obtain a powdery supported gold catalyst C. The space velocity was 7000mL·h ^-1 ·g ^-1 _cat , and the other catalyst evaluation conditions were the same as in Example 1. The catalytic reaction results are shown in Table 1.

Example 4

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 100μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1h, 50mL of the leach solution in Example 1 was added, continued to stir for 1h, then suction filtered, washed with 500mL of deionized water, dried under vacuum at 50°C for 24h, and activated under air atmosphere at 375°C for 6h to obtain a powdery supported gold catalyst D. Catalyst evaluation conditions are the same as in Example 3, and the catalytic reaction results are shown in Table 1.

Example 5

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 200μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1h, 50mL of the leach solution in Example 1 was added, continued to stir for 1h, then suction filtered, washed with 500mL of deionized water, dried under vacuum at 50°C for 24h, and activated under air atmosphere at 375°C for 6h to obtain a powdery supported gold catalyst E. Catalyst evaluation conditions are the same as in Example 3, and the catalytic reaction results are shown in Table 1.

Example 6

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 100μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1 hour, 50 mL of the leaching solution in Example 1 was added, continued to stir for 1 hour, then suction filtered, washed with 500 mL of deionized water, dried under vacuum at 50°C for 24 hours, and activated under air atmosphere at 375°C for 6 hours to obtain a powdery supported gold catalyst F. The catalytic reaction temperature was 280° C., and the other catalyst evaluation conditions were the same as in Example 3. The catalytic reaction results are shown in Table 1.

Example 7

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 100μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1h, add 50mL of the leachate in Example 1, continue to stir for 1h, then filter with suction, wash with 500mL of deionized water, dry at 50°C for 24h in vacuum, and activate at 375°C for 6h in an air atmosphere to obtain a powdery supported gold catalyst G. The catalytic reaction temperature was 260° C., and the other catalyst evaluation conditions were the same as in Example 3. The catalytic reaction results are shown in Table 1.

Example 8

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 100μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1h, 50mL of the leachate in Example 1 was added, continued to stir for 1h, then suction filtered, washed with 500mL of deionized water, dried under vacuum at 50°C for 24h, and activated under air atmosphere at 375°C for 6h to obtain a powdery supported gold catalyst H. The catalytic reaction temperature was 240° C., and the other catalyst evaluation conditions were the same as in Example 3. The catalytic reaction results are shown in Table 1.

Example 9

Take 50mL of deionized water in the Erlenmeyer flask, and add 0.5g of titanium silicon molecular sieve, 1040μL concentration of 0.04856mol/L of chloroauric acid solution and 100μL of ionic liquid [Bpy][N(CN) ₂ ], and stir After 1h, 50mL of the leach solution in Example 1 was added, continued stirring for 1h, then suction filtered, washed with 500mL of deionized water, dried under vacuum at 50°C for 24h, and activated under air atmosphere at 375°C for 6h to obtain a powdery supported gold catalyst I. The catalytic reaction temperature was 220° C., and the other catalyst evaluation conditions were the same as in Example 3. The catalytic reaction results are shown in Table 1.

Table 1

Table 1 shows the catalytic reaction results of Examples 1-9.

Claims (7)

1. the preparation method of the Au catalyst of preparing epoxypropane by epoxidation of propene, it is characterised in that comprise the following steps:

1) pulverize after plant Cacumen Platycladi being dried, obtain plant Cacumen Platycladi dry powder, add in water, vibration, filter, obtain plant biomass leachate；

2) in water, add HTS, gold presoma gold chloride (HAuCl₄) aqueous solution and ionic liquid [Bpy] [N (CN)₂], obtain solution A；Described water, HTS, ionic liquid [Bpy] [N (CN)₂] proportioning be 50mL: 0.5g: (0～300) μ L, wherein water and ionic liquid [Bpy] [N (CN)₂] calculate by volume, HTS is calculated in mass, ionic liquid [Bpy] [N (CN)₂] it is not 0；

3) by step 1) in the plant biomass leachate that obtains add step 2) in the solution A that obtains, obtain solution B；

4) by step 3) solution B that obtains carries out sucking filtration, washing, dried activation 6h at 375 DEG C, obtains the Au catalyst of preparing epoxypropane by epoxidation of propene, and the Au catalyst of the preparing epoxypropane by epoxidation of propene of gained is powdered loaded type Au catalyst；The load capacity of the Au catalyst gold of described preparing epoxypropane by epoxidation of propene is 0.25%～4.0%.

2. the preparation method of the Au catalyst of preparing epoxypropane by epoxidation of propene as claimed in claim 1, it is characterized in that in step 1) in, the proportioning of described plant Cacumen Platycladi dry powder and water is 10g: 1L, wherein, plant Cacumen Platycladi dry powder is calculated in mass, and water is calculated by volume.

3. the preparation method of the Au catalyst of preparing epoxypropane by epoxidation of propene as claimed in claim 1, it is characterised in that in step 1) in, described hydromining deionized water.

4. the preparation method of the as claimed in claim 1 Au catalyst of preparing epoxypropane by epoxidation of propene, it is characterised in that in step 1) in, described vibration is placed in shaking table vibration 2h.

5. the preparation method of the as claimed in claim 1 Au catalyst of preparing epoxypropane by epoxidation of propene, it is characterised in that in step 3) in, the addition of described plant biomass leachate and step 1) in the volume ratio of water be 50mL: 1L.

6. the preparation method of the Au catalyst of preparing epoxypropane by epoxidation of propene as claimed in claim 1, it is characterised in that in step 4) in, described washing adopts deionized water wash.

7. the preparation method of the Au catalyst of preparing epoxypropane by epoxidation of propene as claimed in claim 1, it is characterised in that in step 4) in, described drying is dry 24h under 50 DEG C of vacuum.