Bimetal modified phosphorus-containing molecular sieve catalyst as well as preparation method and application thereof

Abstract

The invention discloses a bimetallic modified phosphorus-containing molecular sieve catalyst and a preparation method and application thereof.The preparation method of the bimetallic modified phosphorus-containing molecular sieve catalyst comprises the following steps that S1, an activated molecular sieve and a Mo compound are added into deionized water, heating and open overnight stirring are conducted, and solid powder A is obtained, solid powder B is obtained by calcining the molecular sieve in an air atmosphere at 550 DEG C for 2 hours, the molecular sieve is one of TS-1, SBA-15, gamma-Al2O3, HZSM-5 and PZSM-5, and the Mo compound is one of sodium molybdate, ammonium dimolybdate and molybdenum acetylacetonate; and S2, adding the solid powder B and a metal compound into deionized water, heating, opening and overnight stirring to obtain solid powder C, and calcining in an air atmosphere of 400-800 DEG C for 1-5 hours to obtain solid powder D which is the bimetallic modified phosphorus-containing molecular sieve catalyst, the metal compound is selected from one of iridium acetylacetonate, nickel acetylacetonate, ruthenium trichloride, ruthenium acetylacetonate, cobalt nitrate, platinum tetrachloride and dinitroso diammineplatinum. When the bimetallic modified phosphorus-containing molecular sieve catalyst is used for preparing 1, 2-epoxyhexane from 1-hexene, the bimetallic modified phosphorus-containing molecular sieve catalyst has high 1, 2-epoxyhexane selectivity, and can be used for efficiently preparing 1, 2-epoxyhexane from 1-hexene.

Description

Technical Field

[0001] The present invention relates to the technical field of material preparation, and more specifically, to a preparation method and application of a bimetal-modified phosphorus-containing molecular sieve catalyst. Background Art

[0002] 1,2-Epoxyhexane is an important platform compound, which can be used to produce high-value-added products such as oil-soluble polyethers, polyurethanes, and surfactants, and is widely used in many fields such as lubricating oils, engineering plastics, industry, and daily necessities. The industrial olefin epoxidation methods mainly include the chlorohydrin method, the direct oxidation method, and the co-oxidation method. The chlorohydrin method belongs to the phased-out technology due to serious corrosion and pollution problems. The direct oxidation method is divided into the HPPO method and the oxygen oxidation method. The HPPO method has poor stability and low safety; the oxygen oxidation method is in the basic research stage. The co-oxidation method (ethylbenzene, isobutane, cumene method, etc.) activates the C-H bond to prepare organic peroxides, and then oxidizes olefins to prepare epoxides, which is more in line with the theme of green chemistry. Among them, the ethylbenzene co-oxidation method overcomes the disadvantages of the chlorohydrin method such as corrosion and large wastewater volume, and has the advantages of high conversion rate, high selectivity, low cost, and small environmental pollution.

[0003] Chinese Patent CN114733511A discloses an application of a V2O5 / FeVO4 catalyst in the epoxidation reaction of cyclooctene. In this patent, cyclooctene, a solvent, and TBHP are uniformly mixed, and the V2O5 / FeVO4 catalyst is used to react at a certain temperature for a period of time to obtain epoxycyclooctane. Chinese Patent CN105017177A discloses a method for catalyzing the epoxidation of cyclooctene with ammonium perrhenate calixarene. The catalytic method of this invention has low use cost and the catalyst can be reused. However, the catalysts used in the above processes have poor economy, poor catalyst recycling performance, and the epoxidation performance also needs to be improved. Summary of the Invention

[0004] In view of the above deficiencies, the object of the present invention is to provide a bimetal-modified phosphorus-containing molecular sieve catalyst with high activity, high selectivity, and recyclability.

[0005] A further object of the present invention is to provide a preparation method of the bimetal-modified phosphorus-containing molecular sieve catalyst.

[0006] Another object of the present invention is to provide an olefin epoxidation reaction method.

[0007] To this end, the first technical solution provided by the present invention is as follows:

[0008] A preparation method of a bimetal-modified phosphorus-containing molecular sieve catalyst, comprising the following steps:

[0009] S1. Disperse the phosphorus-containing molecular sieve support and molybdenum source compound in deionized water at a mass ratio of 1:(0.05 - 0.15), stir at 80 - 90 °C for 8 - 12 hours, after solid-liquid separation, calcine in air atmosphere at 500 - 550 °C for 2 - 3 hours to obtain a molybdenum-modified intermediate;

[0010] S2. Disperse the molybdenum-modified intermediate and the second metal source compound in deionized water at a molar ratio of molybdenum to the second metal of 1:(0.2 - 5), stir at 80 - 90 °C for 8 - 12 hours, after solid-liquid separation, calcine in air atmosphere at 450 - 650 °C for 1 - 4 hours to obtain a bimetal-modified catalyst.

[0011] Further, in the preparation method of the above bimetal-modified phosphorus-containing molecular sieve catalyst, the phosphorus-containing molecular sieve support is selected from at least one of PZSM-5, TS-1, γ-Al2O3 or mesoporous molecular sieve.

[0012] Further, in the preparation method of the above bimetal-modified phosphorus-containing molecular sieve catalyst, the molybdenum source compound is at least one of ammonium dimolybdate, molybdenum acetylacetonate or sodium molybdate.

[0013] Further, in the preparation method of the above bimetal-modified phosphorus-containing molecular sieve catalyst, the second metal source compound is at least one of acetylacetonates, nitrates or chlorides of ruthenium, iridium, platinum, nickel or cobalt.

[0014] Further, in the preparation method of the above bimetal-modified phosphorus-containing molecular sieve catalyst, the metal compound is selected from one of iridium acetylacetonate, nickel acetylpyruvate, ruthenium trichloride, ruthenium acetylacetonate, cobalt nitrate, platinum tetrachloride, platinum dinitrodiamine.

[0015] Further, in the preparation method of the above bimetal-modified phosphorus-containing molecular sieve catalyst, the solid-liquid ratio of the phosphorus-containing molecular sieve support and deionized water in S1 is (0.5 - 2):150 g / mL.

[0016] The second technical solution of the present invention is to provide a bimetal-modified phosphorus-containing molecular sieve catalyst prepared by using the preparation method described in the first technical solution.

[0017] The second technical solution of the present invention is to provide an olefin epoxidation reaction method, including the following steps:

[0018] (1) Sequentially add 5 - 20 mg of the bimetal-modified phosphorus-containing molecular sieve catalyst described in the first technical solution, 0.4 - 0.8 g of an olefin substrate, 10 - 20 mL of an organic solvent; 10 - 20 mL of a reducing agent into a high-pressure reaction kettle;

[0019] (2) After the sealed reaction kettle is charged with 1.3 - 1.6 g of oxygen, stir and react at 120 - 140 °C for 4 - 6 hours;

[0020] (3) After the reaction is completed, cool to room temperature and take samples for analysis.

[0021] Furthermore, for the above-mentioned olefin epoxidation reaction method,

[0022] The organic solvent is selected from at least one of ethylbenzene, acetonitrile or ethyl acetate;

[0023] The reducing agent is selected from one of ethylbenzene, cumene or isobutane.

[0024] The bimetal-modified phosphorus-containing molecular sieve catalyst is Mo1Ru1 / PZSM-5, Mo1Ir1 / PZSM-5, Mo1Pt1 / TS-1, Mo2Ru1 / PZSM-5 or Mo5Ni1 / PZSM-5);

[0025] The olefin substrate is a C4 - C 10 linear or branched olefin; preferably 1-hexene.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The present invention provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which has a high selectivity for 1,2-epoxyhexane when used in the preparation of 1,2-epoxyhexane from 1-hexene, and can be used for the efficient preparation of 1,2-epoxyhexane from 1-hexene.

[0028] 2. The bimetal-modified phosphorus-containing molecular sieve catalyst of the present invention is non-toxic, has stable performance, is easy to separate after the reaction, can be reused, and the catalyst after the reaction is recovered by centrifugation; there is no secondary pollution to the environment. Brief Description of the Drawings

[0029] Figure 1 It is the XRD pattern of PZSM-5, the catalyst described in Example 1 and Example 5.

[0030] Figure 2 It is the XPS full spectrum of PZSM-5, the catalyst described in Example 1 and Example 5.

[0031] Figure 3 It is the thermogravimetric curve of the catalyst described in Example 5. Detailed Description of the Invention

[0032] To describe the technical solution of the present invention more clearly and completely, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, and various changes can be made within the scope defined by the claims of the present invention.

[0033] Example 1

[0034] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0035] S1. Add 1 g of PZSM-5 and 89 mg of ammonium dimolybdate to 150 mL of deionized water, heat at 80 °C with stirring overnight in an open container to obtain solid powder A, and calcine in an air atmosphere at 550 °C for 2 h to obtain Mo / PZSM-5.

[0036] S2. Add 1 g of solid powder B and 197 mg of ruthenium acetylacetonate to 150 mL of deionized water, heat at 90 °C with stirring overnight in an open container to obtain solid powder C, and calcine in an air atmosphere at 500 °C for 2 h to obtain Mo1Ru1 / PZSM-5.

[0037] Example 2

[0038] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0039] S1. Add 1.5 g of PZSM-5 and 89 mg of ammonium dimolybdate to 150 mL of deionized water, heat at 90 °C with stirring overnight in an open container to obtain solid powder A, and calcine in an air atmosphere at 550 °C for 2 h to obtain solid powder B;

[0040] S2. Add 1.5 g of solid powder B and 127 mg of iridium acetylacetonate to 150 mL of deionized water, heat at 90 °C with stirring overnight in an open container to obtain solid powder C, and calcine in an air atmosphere at 650 °C for 3 h to obtain Mo1Ir1 / PZSM-5.

[0041] Example 3

[0042] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0043] S1. Add 2 g of TS-1 and 102 mg of sodium molybdate to 150 mL of deionized water, heat at 80 °C with stirring overnight in an open container to obtain solid powder A, and calcine in an air atmosphere at 550 °C for 2 h to obtain solid powder B;

[0044] S2. Add 2 g of solid powder B and 82 mg of diaminodinitroplatinum to 150 mL of deionized water, heat at 80 °C with stirring overnight under an open atmosphere to obtain solid powder C, and calcine at 450 °C in an air atmosphere for 4 h to obtain Mo1Pt1 / TS-1.

[0045] Example 4

[0046] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0047] S1. Add 1 g of PZSM-5 and 132 mg of molybdenum acetylacetonate to 150 mL of deionized water, heat at 90 °C with stirring overnight under an open atmosphere to obtain solid powder A, and calcine at 550 °C in an air atmosphere for 2 h to obtain solid powder B;

[0048] S2. Add 1 g of solid powder B and 98 mg of ruthenium acetylacetonate to 150 mL of deionized water, heat at 90 °C with stirring overnight under an open atmosphere to obtain solid powder C, and calcine at 650 °C in an air atmosphere for 2 h to obtain Mo2Ru1 / PZSM-5.

[0049] Example 5

[0050] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0051] S1. Add 1 g of PZSM-5 and 89 mg of ammonium dimolybdate to 150 mL of deionized water, heat at 80 °C with stirring overnight under an open atmosphere to obtain solid powder A, and calcine at 550 °C in an air atmosphere for 2 h to obtain solid powder B;

[0052] S2. Add 1 g of solid powder B and 44 mg of nickel acetylacetonate to 150 mL of deionized water, heat at 80 °C with stirring overnight under an open atmosphere to obtain solid powder C, and calcine at 550 °C in an air atmosphere for 2 h to obtain Mo5Ni1 / PZSM-5.

[0053] Example 6

[0054] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0055] S1. Add 2 g of γ-Al2O3 and 102 mg of sodium molybdate to 150 mL of deionized water, heat at 80 °C with stirring overnight under an open atmosphere to obtain solid powder A, and calcine at 550 °C in an air atmosphere for 2 h to obtain solid powder B;

[0056] S2. Add 2 g of solid powder B and 25 mg of platinum tetrachloride to 150 mL of deionized water, heat at 80 °C with stirring overnight under an open atmosphere to obtain solid powder C, and calcine at 500 °C in an air atmosphere for 3 h to obtain Mo3Pt1 / γ-Al2O3.

[0057] Example 7

[0058] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0059] S1. Add 1.5 g of SBA-15 and 132 mg of molybdenum acetylacetonate to 150 mL of deionized water, heat at 80 °C with stirring overnight in an open container to obtain solid powder A, and calcine in an air atmosphere at 550 °C for 2 h to obtain solid powder B;

[0060] S2. Add 1.5 g of solid powder B and 132 mg of cobalt nitrate to 150 mL of deionized water, heat at 80 °C with stirring overnight in an open container to obtain solid powder C, and calcine in an air atmosphere at 600 °C for 1 h to obtain Mo1Co1 / SBA-15.

[0061] Example 8

[0062] This example provides a bimetal-modified phosphorus-containing molecular sieve catalyst, which is prepared by the following steps:

[0063] S1. Add 1 g of PZSM-5 and 89 mg of ammonium dimolybdate to 150 mL of deionized water, heat at 80 °C with stirring overnight in an open container to obtain solid powder A, and calcine in an air atmosphere at 550 °C for 2 h to obtain solid powder B;

[0064] S2. Add 1 g of solid powder B and 219 mg of nickel acetylacetonate to 150 mL of deionized water, heat at 80 °C with stirring overnight in an open container to obtain solid powder C, and calcine in an air atmosphere at 600 °C for 1 h to obtain Mo1Ni1 / PZSM-5.

[0065] To verify the catalyst provided in this application, the XRD patterns ( Figure 1 ) and XPS full spectra ( Figure 2 ) of PZSM-5, the catalyst described in Example 1, and the catalyst described in Example 5 are given below.

[0066] It can be seen from Figure 1 that the catalyst in Example 5 shows obvious diffraction peaks at specific diffraction angles, indicating that the crystal structure of the catalyst is well maintained and specific active sites may be formed. Compared with the unmodified PZSM-5, the positions of the diffraction peaks of the catalyst in Example 5 are shifted, which may be due to the introduction of bimetals leading to fine-tuning of the catalyst structure, thereby affecting its catalytic performance.

[0067] From Figure 2It can be seen from the XPS full spectrum in [reference] that in addition to containing P, Al, and Si elements in the ZSM-5 framework, the catalyst in Example 5 has successfully introduced Mo and a second metal element (such as Ru or Ni), which further confirms that the bimetal has been successfully loaded onto the phosphorus-containing molecular sieve support.

[0068] Under a nitrogen atmosphere and at a heating rate of 10 K / min, the thermal stability of the catalyst was evaluated by a thermogravimetric analyzer. From the thermogravimetric curve Figure 3 it can be seen that the total mass loss of the catalyst in Example 5 was 7.17%, and the main reason for the mass loss was the evaporation of water in the catalyst.

[0069] Application Example 1

[0070] In a 100 mL stainless steel autoclave with a PTFE inner liner, 10 mg of the catalyst prepared in Example 5, 0.4 g of 1-hexene, 50 mg of biphenyl as an internal standard, and 20 mL of ethylbenzene were added in sequence; after sealing the autoclave, 1.3 g of oxygen was introduced. The reaction was stirred at 130 °C for 5 h. After the reaction was completed, it was cooled to room temperature with ice water, and a sample was taken for gas chromatography analysis. The conversion rate of 1-hexene was measured to be 40.0%, and the selectivity of 1,2-epoxyhexane was 94.1%.

[0071] Application Example 2

[0072] In a 100 mL stainless steel autoclave with a PTFE inner liner, 15 mg of the catalyst prepared in Example 3, 0.6 g of 1-hexene, 4 mL of acetonitrile, 50 mg of biphenyl as an internal standard, and 16 mL of ethylbenzene were added in sequence; after sealing the autoclave, 1.5 g of oxygen was introduced. The reaction was stirred at 120 °C for 6 h. After the reaction was completed, it was cooled to room temperature with ice water, and a sample was taken for gas chromatography analysis. The conversion rate of 1-hexene was measured to be 25.4%, and the selectivity of 1,2-epoxyhexane was 86.1%.

[0073] Application Example 3

[0074] In a 100 mL stainless steel autoclave with a PTFE inner liner, 20 mg of the catalyst prepared in Example 7, 0.6 g of 1-hexene, 6 mL of ethyl acetate, 50 mg of biphenyl as an internal standard, and 14 mL of ethylbenzene were added in sequence; after sealing the autoclave, 1.5 g of oxygen was introduced. The reaction was stirred at 140 °C for 4 h. After the reaction was completed, it was cooled to room temperature with ice water, and a sample was taken for gas chromatography analysis. The conversion rate of 1-hexene was measured to be 31.6%, and the selectivity of 1,2-epoxyhexane was 88.7%.

[0075] Application Example 4

[0076] In a 100 mL stainless steel autoclave with a PTFE liner, the catalyst prepared in Example 4 (15 mg), 1-hexene (0.8 g), acetonitrile (10 mL), biphenyl (50 mg) as internal standard, and ethylbenzene (10 mL) were added in sequence. After sealing the autoclave, 1.6 g of oxygen was introduced. The reaction was stirred at 125 °C for 6 h. After the reaction was completed, it was cooled to room temperature with ice water, and a sample was taken for gas chromatography analysis. The conversion rate of 1-hexene was measured to be 29.4%, and the selectivity of 1,2-epoxyhexane was 89.2%.

[0077] Application Example 5

[0078] In a 100 mL stainless steel autoclave with a PTFE liner, the catalyst prepared in Example 2 (10 mg), 1-hexene (0.4 g), benzonitrile (0 mL), biphenyl (50 mg) as internal standard, and ethylbenzene (20 mL) were added in sequence. After sealing the autoclave, 1.3 g of oxygen was introduced. The reaction was stirred at 130 °C for 5 h. After the reaction was completed, it was cooled to room temperature with ice water, and a sample was taken for gas chromatography analysis. The conversion rate of 1-hexene was measured to be 33.7%, and the selectivity of 1,2-epoxyhexane was 88.3%.

[0079] Application Example 6

[0080] In a 100 mL stainless steel autoclave with a PTFE liner, the catalyst prepared in Example 5 (100 mg), 1-hexene (0.6 g), acetonitrile (20 mL), biphenyl (50 mg) as internal standard, and isobutane (0.4 g) were added in sequence. After sealing the autoclave, 1.2 g of oxygen was introduced. The reaction was stirred at 130 °C for 6 h. After the reaction was completed, it was cooled to room temperature with ice water, and a sample was taken for gas chromatography analysis. The conversion rate of 1-hexene was measured to be 26.5%, and the selectivity of 1,2-epoxyhexane was 86.3%.

[0081] Application Example 7

[0082] A reuse experiment was carried out under the conditions of Application Example 1 by adding 20 mg of the catalyst of Example 5. After the reaction was completed, the solution containing the catalyst was centrifuged using a centrifuge and dried in an oven. In a 100 mL stainless steel autoclave with a PTFE liner, the used catalyst (10 mg), 1-hexene (0.4 g), biphenyl (50 mg) as internal standard, and ethylbenzene (20 mL) were added in sequence. After sealing the autoclave, 1.3 g of oxygen was introduced. The reaction was stirred at 130 °C for 5 h. After the reaction was completed, it was cooled to room temperature with ice water, and a sample was taken for gas chromatography analysis. The conversion rate of 1-hexene was measured to be 37.4%, and the selectivity of 1,2-epoxyhexane was 92.8%.

[0083] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a bimetal-modified phosphorus-containing molecular sieve catalyst, characterized in that, It includes the following steps: S1. Dispersing the phosphorus-containing molecular sieve support and the molybdenum source compound at a mass ratio of 1:(0.05 - 0.15) in deionized water, stirring at 80 - 90 °C for 8 - 12 hours, performing solid-liquid separation, and then calcining in an air atmosphere at 500 - 550 °C for 2 - 3 hours to obtain a molybdenum-modified intermediate; S2. Dispersing the molybdenum-modified intermediate and the second metal source compound at a molar ratio of molybdenum to the second metal of 1:(0.2 - 5) in deionized water, stirring at 80 - 90 °C for 8 - 12 hours, performing solid-liquid separation, and then calcining in an air atmosphere at 450 - 650 °C for 1 - 4 hours to obtain a bimetal-modified catalyst.

2. The preparation method of the bimetal-modified phosphorus-containing molecular sieve catalyst according to claim 1, characterized in that: The phosphorus-containing molecular sieve support is selected from at least one of PZSM-5, TS-1, γ-Al2O3 or mesoporous molecular sieve.

3. The preparation method of the bimetal-modified phosphorus-containing molecular sieve catalyst according to claim 1, characterized in that: The molybdenum source compound is at least one of ammonium dimolybdate, molybdenum acetylacetonate or sodium molybdate.

4. The preparation method of the bimetal-modified phosphorus-containing molecular sieve catalyst according to claim 1, wherein: The second metal source compound is at least one of acetylacetonate, nitrate or chloride salts of ruthenium, iridium, platinum, nickel or cobalt.

5. The preparation method of the bimetal-modified phosphorus-containing molecular sieve catalyst according to claim 4, characterized in that: The metal compound is selected from one of iridium acetylacetonate, nickel acetylpyruvate, ruthenium trichloride, ruthenium acetylacetonate, cobalt nitrate, platinum tetrachloride, platinum dinitrodiamine.

6. The preparation method of the bimetal-modified phosphorus-containing molecular sieve catalyst according to claim 1, characterized in that: In S1, the solid-liquid ratio of the molecular sieve and deionized water is (0.5 - 2):150 g / mL.

7. A bimetal-modified phosphorus-containing molecular sieve catalyst, characterized in that, Prepared by using the preparation method described in any one of claims 1 - 6.

8. A method for olefin epoxidation, characterized in that, It includes the following steps: (1) Sequentially adding 5 - 20 mg of the bimetal-modified phosphorus-containing molecular sieve catalyst described in claim 7, 0.4 - 0.8 g of an olefin substrate, 10 - 20 mL of an organic solvent; 10 - 20 mL of a reducing agent into a high-pressure reaction kettle; (2) After sealing the reaction kettle, introducing 1.3 - 1.6 g of oxygen, and stirring and reacting at 120 - 140 °C for 4 - 6 hours; (3) After the reaction is completed, cooling to room temperature and sampling for analysis.

9. According to an olefin epoxidation reaction method described in claim 8, characterized in that The organic solvent is selected from at least one of ethylbenzene, acetonitrile or ethyl acetate; The reducing agent is selected from one of ethylbenzene, cumene or isobutane. The bimetal-modified phosphorus-containing molecular sieve catalyst is Mo1Ru1 / PZSM-5, Mo1Ir1 / PZSM-5, Mo1Pt1 / TS-1, Mo2Ru1 / PZSM-5 or Mo5Ni1 / PZSM-5); The olefin substrate is a C4-C 10 linear or branched olefin.

10. A method for epoxidation of olefins according to claim 9, characterized in that, The olefin substrate is 1-hexene.

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