A Zn-regulated PtSn / Al2O3 catalyst, preparation method and application in propane dehydrogenation

Abstract

The application discloses a Zn-regulated PtSn / Al2O3 catalyst and a preparation method and propane dehydrogenation application thereof, and the preparation method comprises the following steps: preparing the Zn-regulated PtSn / Al2O3 catalyst by using an electrostatic adsorption method, by taking a metal ion source containing platinum and tin and a Pt coordination organic compound in an organic solvent; and the metal ion source containing platinum and tin comprises potassium chloroplatinite and stannous chloride. In the application, the Zn-regulated PtSn / Al2O3 catalyst is prepared by taking the metal ion source containing platinum and tin and the Pt coordination organic compound in the organic solvent and using the electrostatic adsorption method, the Zn element is used for modification, the stability of the catalyst is greatly improved, and the catalyst has high conversion rate and excellent stability. In the application, raw materials are low in price, samples have regular microstructures, high activity, excellent thermal stability and extremely high propylene selectivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of propane dehydrogenation, and particularly relates to a Zn-regulated PtSn / Al2O3 catalyst, a preparation method and propane dehydrogenation application. BACKGROUND

[0002] It is a general trend to use traditional basic chemical raw materials to prepare high-end chemicals and new materials, and to realize the resource transformation of low-value organic matter. Propylene is an important organic basic chemical raw material with a production second only to ethylene, and is widely used to produce chemical products such as polypropylene, acrylonitrile, and epoxy propane, and is a basic raw material for the three major synthetic materials (plastics, rubber, and fiber). The continuous development of the global economy has led to a rapid increase in the demand for propylene. There are mainly four kinds of processes for producing propylene at home and abroad: catalytic cracking technology, steam cracking device by-product propylene technology, coal or methanol to olefin technology, and propane dehydrogenation technology (PDH technology). At present, the traditional process for producing propylene in China is still catalytic cracking of petroleum and cracking of naphtha. However, petroleum resources are becoming increasingly scarce, and the price is rising, so the production technology of propylene using petroleum as raw material needs to be further updated and optimized, and at the same time, the development of other propylene production technologies is also imminent. In recent years, the large-scale exploitation of shale gas has effectively increased the production of propane, providing sufficient raw materials for propane dehydrogenation to produce propylene, and propane dehydrogenation is considered to be one of the most promising methods for producing propylene.

[0003] Propane catalytic dehydrogenation technology is mainly divided into oxidative dehydrogenation and direct dehydrogenation according to different reaction gases. Propane oxidative dehydrogenation technology (OPDH) adds an oxidizing gas (such as nitrogen oxide, carbon dioxide, and oxygen) in the reaction process, and the reaction formula of propane oxidative dehydrogenation is as formula (1). When oxygen is used as the oxidizing gas, the thermodynamic limit is broken, and the reaction is exothermic, so the required reaction temperature is low and the energy consumption is small, but propane and generated propylene are easy to be oxidized to produce CO or CO2. In recent years, propane oxidative dehydrogenation reaction has attracted people's attention, and many new types of metal oxide catalysts with high efficiency have also been developed, such as MnO x , CoO x , and VO x Although propane oxidative dehydrogenation has high activity, it has low selectivity for propylene, the product distribution is complex, separation is difficult, and it is difficult to carry out industrial production, which makes propane oxidative dehydrogenation limited to conceptual research.

[0004] C3H8 + O2 → C3H6 + H2O (1)

[0005]

[0006] Compared with OPDH, propane direct dehydrogenation (PDH) has high selectivity and high yield, and has broad industrial application prospects. Pt-based and CrO xBase catalysts are applied in commercial PDH process due to their excellent activity and high propylene yield. x Base catalysts are safe and environmentally friendly, and are more scientific in basic research, which have attracted extensive attention of researchers at home and abroad. The reaction formula of propane direct dehydrogenation (PDH) is shown as formula (2). The reaction temperature is usually between 500-600℃. As an endothermic process, high temperature environment and harsh conditions seriously limit the development of catalysts. In the dehydrogenation process, cracking, hydrogenolysis and deep dehydrogenation and other side reactions inevitably occur, and coke deposition is formed on the surface of the catalyst, which seriously reduces the activity and stability of the catalyst. For Pt-based catalysts, surface carbonization is one of the main reasons for catalyst deactivation. The dehydrogenation reaction of propane on Pt-based catalysts is a structure-insensitive reaction, while cracking, hydrolysis, isomerization and carbon deposition are structure-sensitive reactions. The industrial catalyst widely used in PDH reaction is mainly PtSn / Al2O3. Although the catalyst has good initial activity, the high-temperature thermal stability is still not satisfactory, and the catalyst will be rapidly deactivated in a short time, which results in poor economic benefits and waste of resources. SUMMARY

[0007] In order to overcome the problem of poor high-temperature thermal stability of the catalyst in the prior art, the purpose of the present application is to provide a Zn-regulated PtSn / Al2O3 catalyst, a preparation method and a propane dehydrogenation application. The catalyst prepared by the method has good catalytic activity and excellent high-temperature stability, and can be used in industrial propane dehydrogenation reaction to prepare propylene.

[0008] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0009] A preparation method of a Zn-regulated PtSn / Al2O3 catalyst, wherein a metal ion source containing platinum and tin and a Pt coordination organic matter are prepared into a Zn-regulated PtSn / Al2O3 catalyst by using an electrostatic adsorption method in an organic solvent. The metal ion source containing platinum and tin includes potassium chloroplatinite and stannous chloride.

[0010] Further, the method comprises the following steps:

[0011] An acid solution of zinc chloride is added to a potassium chloroplatinite solution, and a dichloromethane solution of a Pt coordination organic matter is added, then the lower layer is taken out to obtain a clear solution;

[0012] A tetrahydrofuran solution of stannous chloride is added to the clear solution, and the mixture is stirred uniformly to obtain a mixed solution;

[0013] A tetrahydrofuran suspension of aluminum oxide is added to the mixed solution, and a solid is obtained after stirring;

[0014] The solid is dried and calcined to obtain the Zn-regulated PtSn / Al2O3 catalyst.

[0015] Further, the mass ratio of zinc chloride, potassium chloroplatinite and stannous chloride is (0.1-0.7):1:(1-5).

[0016] Further, the Pt-coordinating organic matter is tetrabutylammonium bromide.

[0017] Further, the mass ratio of the Pt-coordinating organic matter and potassium chloroplatinite is 10.0-30.0:10.0-20.0.

[0018] Further, the mass ratio of aluminum oxide and potassium chloroplatinite is 0.600:10.0-20.0.

[0019] Further, the calcination temperature is 500-600 DEG C, and the time is 1-3h.

[0020] Further, the calcination is carried out under the mixed gas of H2 and Ar, and the temperature is raised to 500-600 DEG C at a temperature raising rate of 5-10 DEG C / min.

[0021] A Zn-regulated PtSn / Al2O3 catalyst, wherein the size of the metal cluster of the catalyst is 1-2nm.

[0022] The application of a Zn-regulated PtSn / Al2O3 catalyst in the dehydrogenation of propane.

[0023] Compared with the prior art, the application has the beneficial effects that:

[0024] In the application, the Zn-regulated PtSn / Al2O3 catalyst is prepared by electrostatic adsorption method in an organic solvent by using a Pt-coordinating organic matter and a metal ion source containing platinum and tin, and the stability of the catalyst is greatly improved by using Zn element modification, and the catalyst has high conversion rate and excellent stability.

[0025] The catalyst of the present application has excellent stability in the propane dehydrogenation reaction at 600 DEG C for 2000 min, and the conversion rate of propane is decreased from 44.12% to 41%. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The device structure schematic diagram for the application of the catalyst of the present application;

[0027] In the figure, 1 is a propane gas cylinder, 2 is an argon cylinder, 3 is a hydrogen-argon cylinder, 4 is a first mass flow meter, 5 is a second mass flow meter, 6 is a third mass flow meter, 7 is a first-stage premixing device, 8 is a second-stage premixing device, 9 is a temperature controller, 10 is a catalytic reactor, and 11 is a gas chromatograph.

[0028] Figure 2 The figure is the propane dehydrogenation reaction performance diagram of the comparative examples 1-5 in the present application, and the reaction conditions are: 600 DEG C, 4 mL / min high-purity propane + 36 mL / min high-purity argon.

[0029] Figure 3 The figure is the propane dehydrogenation reaction performance diagram of the examples 1-3 and the comparative example 3 in the present application, and the reaction conditions are: 600 DEG C, 4 mL / min high-purity propane + 36 mL / min hydrogen-argon gas (10% H2+90% Ar).

[0030] Figure 4 The figure is the XRD image of the examples 1-3 and the comparative example 3 in the present application. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present application can be more thoroughly and completely understood.

[0032] Firstly, the preparation method of the PtSn / Al2O3 catalyst in the present application is as follows: potassium chloroplatinate (K2PtCl4) and stannous chloride (SnCl2) are used as metal ion sources, tetrabutylammonium bromide (TBAB) is used as a Pt coordination organic compound, dichloromethane (CH2Cl2) and tetrahydrofuran (THF) are used as metal organic solvents, and the electrostatic adsorption method is used to load the PtSn-complex on Al2O3 to prepare Pt1Snx Pt / Al2O3 catalyst.

[0033] Firstly, the preparation method of the PtSn / Al2O3 catalyst comprises the following steps:

[0034] Preparation of solution A: 10.0-20.0 mg of K2PtCl4 is added into 5.0-10.0 mL of deionized water, and shaken uniformly to obtain a light red transparent and clear solution A;

[0035] Preparation of solution B: 10.0-30.0 mg of tetrabutylammonium bromide (TBAB) is added into 5.0-10.0 mL of dichloromethane (CH2Cl2), and shaken uniformly to obtain a colorless transparent and clear solution B;

[0036] Preparation of solution C: all the solution B is transferred into the solution A by using a rubber bulb dropper, and after being shaken vigorously, the solution is left to stand until the solution is clearly layered, the supernatant is a colorless transparent and clear aqueous phase, and the lower clear liquid is a light red transparent and clear organic solution, and this process realizes the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, a clear solution C is obtained;

[0037] Preparation of solution D: 10.0-40.0 mg of stannous chloride (SnCl2) is dissolved into 1-3 mL of tetrahydrofuran (THF), and after being shaken uniformly, the solution is ultrasonically treated for 20 min, so that the stannous chloride (SnCl2) is completely dissolved, and a solution D is obtained.

[0038] Preparation of solution E: under the condition of room temperature and 500 r / min, a certain amount of the solution D is extremely slowly added into the solution C, and it is observed that the light red solution C gradually changes to brown red, and the stirring is continued for 30 min to obtain a solution E. The molar ratio of K2PtCl4 to SnCl2 is 1:1-5, preferably, the molar ratio of K2PtCl4 to SnCl2 is 1-5:1, preferably 1:1, 2:1, 3:1, 4:1 or 5:1.

[0039] Preparation of suspension F: 6 mL of tetrahydrofuran (THF) is added into 0.600 g of Al2O3, and after being shaken vigorously, the solution is ultrasonically treated for 30 min to obtain an Al2O3 suspension F.

[0040] The suspension F is immediately transferred to solution E, and stirring is continued at room temperature at 500 r / min for 24 h. After stirring, the liquid is removed by centrifugation at 8000 r / min for 10 min, and a light yellow solid product is obtained, which is dried under vacuum at 60 ℃ for 8-12 h. After drying, the Pt1Sn / Al2O3 catalyst is obtained by reduction at 500-600 ℃ under an atmosphere of 40-80 mL / min (10% H2 by volume + 90% Ar by volume) for 1-3 h, with a temperature increasing rate of 5-10 ℃ / min, and natural cooling to room temperature. x / Al2O3 catalyst.

[0041] The Pt1Sn x / Al2O3 catalyst has a metal cluster size of 1-2 nm.

[0042] In the present application, the theoretical loading of Pt is 1 wt%, and the method realizes the transfer of the active phase Pt from the aqueous phase to the organic phase, and the active phase is adsorbed onto the carrier Al2O3 by electrostatic adsorption. In the present application, the precursor of Pt is K2PtCl4, the precursor of Sn is SnCl2, the ligand is tetrabutylammonium bromide, and the organic solvent is dichloromethane and tetrahydrofuran. Only by using these raw materials can a special Pt-Sn complex coordination structure (Pt-Sn complex) be formed.

[0043] The Pt1Sn x / Al2O3 catalyst has a metal cluster size of 1-2 nm.

[0044] Referring to Figure 1 The test device used in the present application includes a high-purity propane gas cylinder 1, a high-purity argon gas cylinder 2, and a high-purity hydrogen-argon gas cylinder 3. The outlet of the high-purity propane gas cylinder 1 is connected to the inlet of a first premixing device 7 through a first mass flowmeter 4. The outlet of the high-purity argon gas cylinder 2 is also connected to the inlet of the first premixing device 7 through a second mass flowmeter 5. The outlet of the high-purity hydrogen-argon gas cylinder 3 is connected to the inlet of the first premixing device 7 through a third mass flowmeter 6. The outlet of the first premixing device 7 is connected to the inlet of a second premixing device 8. The outlet of the second premixing device 8 is connected to the inlet of a catalytic reactor 10. The outlet of the catalytic reactor 10 is connected to a gas chromatograph 11. The catalytic reactor 10 includes a reaction tube. The outlet of the second premixing device 8 is connected to the inlet of the reaction tube. The outlet of the reaction tube is connected to the gas chromatograph 11. A heat insulation layer is arranged on the outer wall of the reaction tube. The first premixing device 7, the second premixing device 8, and the catalytic reactor 10 are all connected to a temperature controller 9.

[0045] The gas flow is strictly controlled by using a mass flow meter: the propane flow is 4 mL / min, and the argon flow is 36 mL / min. The propane and argon pass through the mass flow meter and enter a first-stage and a second-stage premixing device at 120 DEG C in sequence, are fully mixed, and are then introduced into a catalytic reactor. The reaction process is started from room temperature and is heated to 600 DEG C at a heating rate of 5 DEG C / min. During the heating process, only high-purity argon is introduced. When the temperature is increased to 600 DEG C, the propane gas flow is introduced. Subsequently, the tail gas of the reaction device is introduced into a gas chromatograph, and the composition of the tail gas is detected.

[0046] In the application in the field of propane dehydrogenation, the reaction principle is as follows: propane is adsorbed on the surface of the catalyst and is combined with an active phase. The primary carbon bond of propane is broken and one hydrogen atom is removed. Subsequently, the secondary carbon bond is broken and one hydrogen atom is removed. The two removed hydrogen atoms are combined to generate hydrogen. The broken primary carbon bond and secondary carbon bond are combined to be converted into a carbon-carbon double bond, and propylene is generated.

[0047] In the present application, after the best PtSn ratio is screened, the stability of the catalyst is greatly improved by using Zn element for modification.

[0048] Firstly, the best PtSn ratio is screened in the present application.

[0049] Comparative Example 1

[0050] 12.8 mg of K2PtCl4 is added into 6.0 mL of deionized water, and is shaken uniformly to obtain a light red transparent and clear uniform solution A;

[0051] 20.0 mg of tetrabutylammonium bromide (TBAB) is added into 6.0 mL of dichloromethane (CH2Cl2), and is shaken uniformly to obtain a colorless transparent and clear uniform solution B;

[0052] All of the solution B is transferred into the solution A by using a rubber head dropper. After being shaken violently and being left to stand until the solution is clearly layered, the supernatant is a colorless transparent and clear water phase, and the lower clear liquid is a light red transparent and clear organic solution. After the supernatant is removed, the clear lower clear liquid C is obtained.

[0053] Dissolve 35.0 mg of stannous chloride (SnCl2) into 2 mL of tetrahydrofuran (THF), shake well and sonicate for 20 min to make sure that the stannous chloride (SnCl2) is completely dissolved, to obtain solution D. At room temperature, 500 r / min, add 0.333 mL of solution D into solution C very slowly, observe that the light red solution C gradually changes to brownish red, to obtain solution E, continue to stir for 30 min. The molar ratio of Pt to Sn is 1:1. Add 6 mL of tetrahydrofuran (THF) into 0.600 g of Al2O3, shake well and sonicate for 30 min to obtain Al2O3 suspension F. Immediately transfer F into solution E, continue to stir at room temperature, 500 r / min for 24 h. After stirring, remove the liquid by centrifugation at 8000 r / min for 10 min to obtain a light yellow solid product, vacuum dry at 60 °C for 12 h. After drying, reduce at 600 °C for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar), the heating rate is 5 °C / min, naturally cool to room temperature to obtain Pt1Sn1 / Al2O3 catalyst.

[0054] Comparative Example 2

[0055] Add 12.8 mg of K2PtCl4 into 6.0 mL of deionized water, shake well to obtain a light red transparent clear homogeneous solution A;

[0056] Add 20.0 mg of tetrabutylammonium bromide (TBAB) into 6.0 mL of dichloromethane (CH2Cl2), shake well to obtain a colorless transparent clear homogeneous solution B;

[0057] Transfer solution B into solution A by using a rubber bulb dropper, shake well and let it stand until the solution is clearly layered, the supernatant is a colorless transparent clear aqueous phase, and the lower clear liquid is a light red transparent clear organic solution. After removing the supernatant, obtain clear lower clear liquid C.

[0058] Dissolve 35.0 mg of stannous chloride (SnCl2) into 2 mL of tetrahydrofuran (THF), shake well and sonicate for 20 min to make sure that the stannous chloride (SnCl2) is completely dissolved, to obtain solution D. At room temperature, 500 r / min, add 0.667 mL of solution D into solution C very slowly, observe that the light red solution C gradually changes to brownish red, to obtain solution E, continue to stir for 30 min. The molar ratio of Pt to Sn is 1 :2. Add 6 mL of tetrahydrofuran (THF) into 0.600 g of Al2O3, shake well and sonicate for 30 min to obtain Al2O3 suspension F. Immediately transfer F into solution E, continue to stir at room temperature, 500 r / min for 24 h. After stirring, remove the liquid by centrifugation at 8000 r / min for 10 min to obtain a light yellow solid product, vacuum dry at 60 °C for 12 h. After drying, reduce at 600 °C for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar), the heating rate is 5 °C / min, naturally cool to room temperature to obtain Pt1Sn2 / Al2O3 catalyst.

[0059] Comparative Example 3

[0060] Add 12.8 mg of K2PtCl4 into 6.0 mL of deionized water, shake well to obtain a light red transparent clear homogeneous solution A;

[0061] Add 20.0 mg of tetrabutylammonium bromide (TBAB) into 6.0 mL of dichloromethane (CH2Cl2), shake well to obtain a colorless transparent clear homogeneous solution B;

[0062] Transfer solution B into solution A by using a rubber bulb dropper, shake well and let it stand until the solution is clearly layered, the supernatant is a colorless transparent clear aqueous phase, and the lower clear liquid is a light red transparent clear organic solution. After removing the supernatant, obtain clear lower clear liquid C.

[0063] Dissolve 35.0 mg of stannous chloride (SnCl2) into 2 mL of tetrahydrofuran (THF), shake well and sonicate for 20 min to make sure that the stannous chloride (SnCl2) is completely dissolved, to obtain solution D. At room temperature, 500 r / min, add 1.000 mL of solution D into solution C very slowly, observe that the light red solution C gradually changes to brownish red, to obtain solution E, continue to stir for 30 min. The molar ratio of Pt to Sn is 1 :3. Add 6 mL of tetrahydrofuran (THF) into 0.600 g of Al2O3, shake well and sonicate for 30 min to obtain Al2O3 suspension F. Immediately transfer F into solution E, continue to stir at room temperature, 500 r / min for 24 h. After stirring, remove the liquid by centrifugation at 8000 r / min for 10 min to obtain a light yellow solid product, vacuum dry at 60 °C for 12 h. After drying, reduce at 600 °C for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar), the heating rate is 5 °C / min, naturally cool to room temperature to obtain Pt1Sn3 / Al2O3 catalyst.

[0064] Comparative Example 4

[0065] Add 12.8 mg of K2PtCl4 into 6.0 mL of deionized water, shake well to obtain a light red transparent clear homogeneous solution A;

[0066] Add 20.0 mg of tetrabutylammonium bromide (TBAB) into 6.0 mL of dichloromethane (CH2Cl2), shake well to obtain a colorless transparent clear homogeneous solution B;

[0067] Transfer solution B into solution A by using a rubber bulb dropper, shake well and let it stand until the solution is clearly layered, the supernatant is a colorless transparent clear aqueous phase, and the lower clear liquid is a light red transparent clear organic solution. After removing the supernatant, obtain clear lower clear liquid C.

[0068] Dissolve 35.0 mg of stannous chloride (SnCl2) into 2 mL of tetrahydrofuran (THF), shake well and sonicate for 20 min to make sure that the stannous chloride (SnCl2) is completely dissolved, to obtain solution D. At room temperature, 500 r / min, add 1.333 mL of solution D into solution C very slowly, observe that the light red solution C gradually changes to brownish red, to obtain solution E, continue to stir for 30 min. The molar ratio of Pt to Sn is 1 :4. Add 6 mL of tetrahydrofuran (THF) into 0.600 g of Al2O3, shake well and sonicate for 30 min to obtain Al2O3 suspension F. Immediately transfer F into solution E, continue to stir at room temperature, 500 r / min for 24 h. After stirring, remove the liquid by centrifugation at 8000 r / min for 10 min to obtain a light yellow solid product, which is dried under vacuum at 60 °C for 12 h. After drying, reduce at 600 °C for 2 h under an atmosphere of 60 mL / min (10% H2+90% Ar), the heating rate is 5 °C / min, and cool down to room temperature naturally, to obtain the Pt1Sn4 / Al2O3 catalyst.

[0069] Comparative Example 5

[0070] Add 12.8 mg of K2PtCl4 into 6.0 mL of deionized water, shake well to obtain a light red transparent clear homogeneous solution A;

[0071] Add 20.0 mg of tetrabutylammonium bromide (TBAB) into 6.0 mL of dichloromethane (CH2Cl2), shake well to obtain a colorless transparent clear homogeneous solution B;

[0072] Transfer solution B into solution A with a rubber bulb dropper, shake well and let it stand until the solution is clearly layered, the supernatant is a colorless transparent clear aqueous phase, and the lower clear liquid is a light red transparent clear organic solution. After removing the supernatant, obtain clear lower clear liquid C.

[0073] Dissolve 35.0 mg of stannous chloride (SnCl2) into 2 mL of tetrahydrofuran (THF), shake well and sonicate for 20 min to make sure SnCl2 is completely dissolved, to obtain solution D. Add 1.667 mL of solution D into solution C very slowly under the condition of room temperature and 500 r / min, observe the color of solution C changing from light red to brown red, to obtain solution E, continue to stir for 30 min. The molar ratio of Pt to Sn is 1:5. Add 6 mL of tetrahydrofuran (THF) into 0.600 g of Al2O3, shake well and sonicate for 30 min to obtain Al2O3 suspension F. Transfer F into solution E immediately, continue to stir for 24 h under the condition of room temperature and 500 r / min. After stirring, remove the liquid by centrifugation at 8000 r / min for 10 min to obtain light yellow solid product, and dry under vacuum at 60 ℃ for 12 h. After drying, reduce at 600 ℃ for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar), the heating rate is 5 ℃ / min, and cool down to room temperature naturally, to obtain Pt1Sn5 / Al2O3 catalyst.

[0074] Pt1Sn x / Al2O3 is used for propane dehydrogenation reaction, and the best sample Pt1Sn3 / Al2O3 is screened out, as shown in Figure 2 , it can be seen that Pt1Sn3 / Al2O3 has the best propane conversion rate, the initial activity is close to 60%, and the catalyst performance decreases from 60% to 30% within 20 h, and the selectivity of propylene is more than 99.9% during this period.

[0075] Example 1

[0076] Prepare solution A: add 12.8 mg of K2PtCl4 into 6.0 mL of deionized water, shake well to obtain light red transparent and clear homogeneous solution A;

[0077] Prepare solution B: add 4.2 mg of ZnCl2 into 200 μL of 0.1 mol / L hydrochloric acid, shake well to obtain colorless transparent and clear homogeneous solution B;

[0078] Take a certain amount of solution B and add it into solution A, shake well to obtain light red transparent and clear homogeneous solution C, and the amount of solution B taken is 20 μL;

[0079] Prepare solution D: add 20.0 mg of tetrabutylammonium bromide (TBAB) into 6.0 mL of dichloromethane (CH2Cl2), shake well to obtain colorless transparent and clear homogeneous solution D;

[0080] Preparation of solution E: All solution D was transferred into solution C with a rubber bulb pipette, after shaking vigorously and standing until the solution was clearly layered, the supernatant was colorless transparent clear aqueous phase, the lower clear solution was light red transparent clear organic solution, this process realized the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, a clear lower clear solution was obtained, and solution E was obtained;

[0081] Preparation of solution F: SnCl2 was dissolved in 1 mL of THF, and after shaking uniformly, it was ultrasonicated for 20 min to make SnCl2 completely dissolved.

[0082] Solution F was added to solution E very slowly under the condition of room temperature and 500 r / min, and it was observed that the light red solution E gradually changed to brown red, and solution G was obtained. Continue to stir for 30 min. The molar ratio of Pt, Zn and Sn is 1:0.1:3;

[0083] Preparation of suspension H: 6 mL of THF was added to 0.600 g of Al2O3, and after shaking vigorously, it was ultrasonicated for 30 min to obtain Al2O3 suspension H.

[0084] Suspension H was immediately transferred to solution G, and stirring was continued at room temperature and 500 r / min for 24 h. After stirring, the liquid was removed by centrifugation at 8000 r / min for 10 min, and a light yellow solid product was obtained. Vacuum drying at 60°C for 12 h. After drying, the catalyst was obtained by reducing at 600°C under the atmosphere of 60 mL / min (10% H2+90% Ar) for 2 h, with a heating rate of 5°C / min. After natural cooling to room temperature, the catalyst Pt1Zn 0.1 Sn3 / Al2O3 was obtained.

[0085] Example 2

[0086] Preparation of solution A: 12.8 mg of K2PtCl4 was added to 6.0 mL of deionized water, and after shaking uniformly, a light red transparent clear homogeneous solution A was obtained;

[0087] Preparation of solution B: 4.2 mg of ZnCl2 was added to 200 μL of 0.1 mol / L hydrochloric acid, and after shaking uniformly, a colorless transparent clear homogeneous solution B was obtained;

[0088] A certain amount of solution B was added to solution A, and after shaking uniformly, a light red transparent clear homogeneous solution C was obtained. The amount of solution B taken was 100 μL;

[0089] Preparation of solution D: 20.0 mg of tetrabutylammonium bromide (TBAB) was added to 6.0 mL of dichloromethane (CH2Cl2), and after shaking uniformly, a colorless transparent clear homogeneous solution D was obtained;

[0090] Transfer solution D into solution C with a rubber bulb pipette, shake vigorously and let it stand until the solution is clearly layered, the supernatant is colorless, transparent and clear aqueous phase, and the lower layer is light red, transparent and clear organic solution. This process realizes the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, clear lower layer E is obtained;

[0091] Prepare solution F: dissolve 17.5 mg of stannous chloride (SnCl2) into 1 mL of tetrahydrofuran (THF), shake uniformly and ultrasonic for 20 min to make stannous chloride (SnCl2) completely dissolved.

[0092] Slowly add solution F into solution E at room temperature and 500 r / min, and observe that the light red solution E gradually changes to brownish red to obtain solution G, and continue to stir for 30 min. The molar ratio of Pt, Zn and Sn is 1:0.5:3.

[0093] Prepare suspension H: add 6 mL of tetrahydrofuran (THF) into 0.600 g of Al2O3, shake vigorously and ultrasonic for 30 min to obtain Al2O3 suspension H. Immediately transfer the suspension H into solution G, continue to stir at room temperature and 500 r / min for 24 h. After stirring, remove the liquid by centrifugation at 8000 r / min for 10 min to obtain light yellow solid product, and vacuum dry at 60°C for 12 h. After drying, reduce at 600°C for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar), the heating rate is 5°C / min, and naturally cool to room temperature to obtain the catalyst, namely Pt1Zn 0.5 Sn3 / Al2O3 catalyst.

[0094] Example 3

[0095] Prepare solution A: add 12.8 mg of K2PtCl4 into 6.0 mL of deionized water, shake uniformly to obtain light red transparent and clear homogeneous solution A;

[0096] Prepare solution B: add 4.2 mg of ZnCl2 into 200 μL of 0.1 mol / L hydrochloric acid, shake uniformly to obtain colorless transparent and clear homogeneous solution B;

[0097] Take a certain amount of solution B and add it into solution A, shake uniformly to obtain light red transparent and clear homogeneous solution C, and the amount of solution B is 140 μL;

[0098] Prepare solution D: add 20.0 mg of tetrabutylammonium bromide (TBAB) into 6.0 mL of dichloromethane (CH2Cl2), shake uniformly to obtain colorless transparent and clear homogeneous solution D;

[0099] Solution D was transferred into solution C with a rubber bulb pipette, after shaking vigorously and standing until the solution was clearly layered, the supernatant was colorless transparent clear aqueous phase, the supernatant was light red transparent clear organic solution, this process realized the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, clear supernatant E was obtained;

[0100] Solution F was prepared: 17.5 mg of stannous chloride (SnCl2) was dissolved in 1 mL of tetrahydrofuran (THF), after shaking uniformly, ultrasonic was performed for 20 min, so that stannous chloride (SnCl2) was completely dissolved.

[0101] Solution F was added into solution E slowly under the condition of room temperature and 500 r / min, it was observed that the light red solution E gradually changed to brown red, solution G was obtained, and the stirring was continued for 30 min. The molar ratio of Pt, Zn and Sn was 1:0.7:3;

[0102] Suspension H was prepared: 6 mL of tetrahydrofuran (THF) was added into 0.600 g of Al2O3, after shaking vigorously, ultrasonic was performed for 30 min to obtain Al2O3 suspension H. The suspension H was immediately transferred into solution G, and the stirring was continued for 24 h under the condition of room temperature and 500 r / min. After the stirring was completed, the liquid was removed after centrifugation at 8000 r / min for 10 min, and a light yellow solid product was obtained, which was vacuum dried at 60°C for 12 h. After the drying was completed, the catalyst was obtained by reduction at 600°C under the atmosphere of 60 mL / min (10% H2+90% Ar) for 2 h, the temperature increasing rate was 5°C / min, and the natural cooling to room temperature was performed, and the catalyst was Pt1Zn 0.7 Sn3 / Al2O3.

[0103] Pt1Zn x Sn3 / Al2O3 was used for propane dehydrogenation reaction, and the best sample Pt1Zn 0.5 Sn3 / Al2O3 was screened.

[0104] Referring to Figure 3 , the doping amount of Zn had different effects on the propane dehydrogenation performance of the sample. The Pt1Sn3 / Al2O3 without doping Zn (Comparative Example 3) decreased from 45% to 34.6% in 500 min, and the decrease rate of the propane conversion rate was 0.0208% / min; compared with Pt1Sn3 / Al2O3, the Pt1Zn 0.1 Sn3 / Al2O3 (Example 1) and the excessive Zn-doped Pt1Zn 0.7The activity and stability of Sn3 / Al2O3 (Example 3) are both decreased to different degrees, from 34% and 34.2% to 22.24% and 25.53% within 500 min, and the propane conversion rate decreases at a rate of 0.0235% / min and 0.01734% / min, respectively; while the Pt1Zn 0.5 The stability of Sn3 / Al2O3 (Example 2) is greatly improved, and the propane conversion rate almost does not decrease within 2000 min, from 44.12% to 41%, and the propane conversion rate decreases at a rate of only 0.00156% / min, greatly improving the stability of the catalyst. All the Pt1Zn x The Sn3 / Al2O3 sample shows more than 99% propylene selectivity during the PDH reaction.

[0105] Referring to Figure 4 All the samples of Examples 1-3 show the same characteristic peaks as the carrier Al2O3, indicating that the active phase is uniformly distributed on the carrier.

[0106] The catalyst prepared by the application has high activity, stability and ultra-high propylene selectivity, and the preparation process is simple and the raw material price is low.

[0107] Example 4

[0108] On the basis of Pt1Sn3 / Al2O3 in Comparative Example 3, Zn element is doped for modification to further improve the performance of the catalyst, and the specific preparation process comprises the following steps:

[0109] First, prepare solution A: add K2PtCl4 into deionized water, shake uniformly, and obtain a light red transparent and clear uniform solution A;

[0110] Prepare solution B: add ZnCl2 into 0.1 mol / L hydrochloric acid, shake uniformly, and obtain a colorless transparent and clear uniform solution B;

[0111] Take a certain amount of solution B and add it to solution A, shake uniformly to obtain a light red transparent and clear uniform solution C;

[0112] Prepare solution D: add tetrabutylammonium bromide (TBAB) into dichloromethane (CH2Cl2), shake uniformly, and obtain a colorless transparent and clear uniform solution D;

[0113] Transfer all the solution D to solution C with a rubber bulb dropper, shake vigorously and then stand until the solution is clearly layered, the supernatant is a colorless transparent and clear aqueous phase, and the lower clear liquid is a light red transparent and clear organic solution, which realizes the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, a clear lower clear liquid is obtained, and solution E is obtained;

[0114] Preparation of solution F: SnCl2 was dissolved in THF, and after shaking well, it was ultrasonicated for 20 min to make sure SnCl2 was completely dissolved.

[0115] Solution F was added into solution E slowly under the condition of 500 r / min at room temperature. The color of solution E changed from light red to brown red, and solution G was obtained. The stirring was continued for 30 min. The molar ratio of ZnCl2, K2PtCl4 and SnCl2 was 0.1:1:2, and the mass ratio of tetrabutylammonium bromide and K2PtCl4 was 1:1.

[0116] Preparation of suspension H: THF was added into Al2O3, and after shaking well, it was ultrasonicated for 30 min to obtain Al2O3 suspension H. Suspension H was immediately transferred into solution G, and the stirring was continued for 24 h under the condition of 500 r / min at room temperature. After the stirring, the liquid was removed by centrifugation at 8000 r / min for 10 min, and a light yellow solid product was obtained. The product was dried at 60 °C for 12 h under vacuum. After drying, Pt1Zn was obtained by reduction at 500 °C for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar) with the heating rate of 10 °C / min. After natural cooling to room temperature, Pt1Zn was obtained. x Sn3 / Al2O3 catalyst. The mass ratio of Al2O3 and K2PtCl4 was 0.600:10.0.

[0117] Example 5

[0118] First, solution A was prepared: K2PtCl4 was added into deionized water, and after shaking well, a light red transparent and clear homogeneous solution A was obtained.

[0119] Solution B was prepared: ZnCl2 was added into 0.1 mol / L hydrochloric acid, and after shaking well, a colorless transparent and clear homogeneous solution B was obtained.

[0120] A certain amount of solution B was added into solution A, and after shaking well, a light red transparent and clear homogeneous solution C was obtained.

[0121] Solution D was prepared: tetrabutylammonium bromide (TBAB) was added into dichloromethane (CH2Cl2), and after shaking well, a colorless transparent and clear homogeneous solution D was obtained.

[0122] Solution D was transferred into solution C by using a rubber bulb dropper, and after shaking well, it was left until the solution was clearly layered. The supernatant was a colorless transparent and clear aqueous phase, and the lower clear liquid was a light red transparent and clear organic solution. This process realized the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, the clear lower clear liquid was obtained, and solution E was obtained.

[0123] Preparation of solution F: SnCl2 was dissolved in THF, and after shaking well, it was ultrasonicated for 20 min to make sure SnCl2 was completely dissolved.

[0124] Solution F was added into solution E slowly under the condition of 500 r / min at room temperature. The color of solution E changed from light red to brown red, and solution G was obtained. The stirring was continued for 30 min. The molar ratio of ZnCl2, K2PtCl4 and SnCl2 was 0.3:1:3, and the mass ratio of tetrabutylammonium bromide and K2PtCl4 was 1:2.

[0125] Preparation of suspension H: THF was added into Al2O3, and after shaking well, it was ultrasonicated for 30 min to obtain Al2O3 suspension H. Suspension H was immediately transferred into solution G, and the stirring was continued for 24 h under the condition of 500 r / min at room temperature. After the stirring, the liquid was removed by centrifugation at 8000 r / min for 10 min, and a light yellow solid product was obtained. The product was dried at 60 °C for 12 h under vacuum. After drying, Pt1Zn was obtained by reduction at 550 °C for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar) with the heating rate of 7 °C / min. After natural cooling to room temperature, Pt1Zn was obtained. x Sn3 / Al2O3 catalyst. The mass ratio of Al2O3 and K2PtCl4 was 0.600:20.0.

[0126] Example 6

[0127] First, solution A was prepared: K2PtCl4 was added into deionized water, and after shaking well, a light red transparent and clear homogeneous solution A was obtained.

[0128] Solution B was prepared: ZnCl2 was added into 0.1 mol / L hydrochloric acid, and after shaking well, a colorless transparent and clear homogeneous solution B was obtained.

[0129] A certain amount of solution B was added into solution A, and after shaking well, a light red transparent and clear homogeneous solution C was obtained.

[0130] Solution D was prepared: tetrabutylammonium bromide (TBAB) was added into dichloromethane (CH2Cl2), and after shaking well, a colorless transparent and clear homogeneous solution D was obtained.

[0131] Solution D was transferred into solution C by using a rubber bulb dropper, and after shaking well, it was left until the solution was clearly layered. The supernatant was a colorless transparent and clear aqueous phase, and the lower clear liquid was a light red transparent and clear organic solution. This process realized the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, the clear lower clear liquid was obtained, and solution E was obtained.

[0132] Preparation of solution F: SnCl2 was dissolved in THF, and then ultrasonic was applied for 20 min to make sure SnCl2 was completely dissolved.

[0133] Solution F was added into solution E slowly under the condition of 500 r / min at room temperature. The color of solution E changed from light red to brown red, and solution G was obtained. The stirring was continued for 30 min. The molar ratio of ZnCl2, K2PtCl4 and SnCl2 was 0.5:1:1, and the mass ratio of tetrabutylammonium bromide and K2PtCl4 was 3:1.

[0134] Preparation of suspension H: THF was added into Al2O3, and then ultrasonic was applied for 30 min to make sure Al2O3 was completely suspended. The suspension H was immediately transferred into solution G, and the stirring was continued for 24 h under the condition of 500 r / min at room temperature. After the stirring, the liquid was removed by centrifugation at 8000 r / min for 10 min, and the light yellow solid product was obtained. The product was dried at 60 °C for 12 h under vacuum. After drying, Pt1Zn was obtained by reduction at 570 °C for 2 h under the atmosphere of 60 mL / min (10% H2+90% Ar) with the heating rate of 6 °C / min. After natural cooling to room temperature, Pt1Zn was obtained. x Sn3 / Al2O3 catalyst. The mass ratio of Al2O3 and K2PtCl4 was 0.600:13.

[0135] Example 7

[0136] First, solution A was prepared: K2PtCl4 was added into deionized water, and then the solution was shaken to make sure K2PtCl4 was completely dissolved, and solution A was obtained.

[0137] Solution B was prepared: ZnCl2 was added into 0.1 mol / L hydrochloric acid, and then the solution was shaken to make sure ZnCl2 was completely dissolved, and solution B was obtained.

[0138] A certain amount of solution B was added into solution A, and then the solution was shaken to make sure the solution was homogeneous, and solution C was obtained.

[0139] Solution D was prepared: tetrabutylammonium bromide (TBAB) was added into dichloromethane (CH2Cl2), and then the solution was shaken to make sure TBAB was completely dissolved, and solution D was obtained.

[0140] Solution D was transferred into solution C by using a rubber bulb dropper, and then the solution was shaken and left until the solution was clearly layered. The supernatant was colorless and transparent, and the lower layer was light red and transparent. This process realized the transfer of Pt element from the aqueous phase to the organic phase. After removing the supernatant, the clear lower layer was obtained, and solution E was obtained.

[0141] Preparation of solution F: SnCl2 was dissolved in THF, and after shaking well, ultrasonic treatment was performed for 20 min to make SnCl2 completely dissolved.

[0142] Solution F was added to solution E slowly under the condition of room temperature and 500 r / min, and the light red solution E was observed to gradually change to brown red to obtain solution G, and the stirring was continued for 30 min. The mass ratio of ZnCl2, K2PtCl4 and SnCl2 was 0.7:1:5; the mass ratio of tetrabutylammonium bromide and potassium chloroplatinate was 3:2.

[0143] Preparation of suspension H: THF was added to Al2O3, and after shaking well, ultrasonic treatment was performed for 30 min to obtain Al2O3 suspension H. The suspension H was immediately transferred to solution G, and the stirring was continued for 24 h under the condition of room temperature and 500 r / min. After the stirring was completed, the liquid was removed by centrifugation at 8000 r / min for 10 min to obtain a light yellow solid product, which was vacuum dried at 60℃ for 12 h. After the drying was completed, Pt1Zn was obtained by reduction at 600℃ under the atmosphere of 60 mL / min (10% H2+90% Ar) for 2 h, and the temperature increasing rate was 5℃ / min, and the natural cooling to room temperature was performed. x Sn3 / Al2O3 catalyst. The mass ratio of Al2O3 and potassium chloroplatinate was 0.600:17.

[0144] The present application is modified on the basis of Pt1Sn x / Al2O3 to further improve the performance. When x=3, the performance of the catalyst is the best, so the Zn element is doped on the basis of Pt1Sn x / Al2O3, and the appropriate amount of Zn has a positive effect on the catalyst, and a small amount and an excessive amount of Zn will have a side effect on the catalyst.

[0145] The above only describes the best embodiments of the present application, but cannot be understood as a limitation on the claims. The present application is not limited to the above embodiments, and the specific structure allows changes. Any changes made within the protection scope of the independent claims of the present application are within the protection scope of the present application.

[0146] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

Claims

1. A process for the preparation of a Zn-modulated PtSn / Al203 catalyst for the dehydrogenation of propane, characterized in that, A Zn-regulated PtSn / Al2O3 catalyst is prepared by electrostatic adsorption method in an organic solvent, using a metal ion source containing platinum and tin and a Pt coordination organic compound; the metal ion source containing platinum and tin includes potassium chloroplatinite and stannous chloride, and the Pt coordination organic compound is tetrabutylammonium bromide; The method comprises the following steps: An acid solution of zinc chloride is added to a solution of potassium chloroplatinite, and a solution of tetrabutylammonium bromide in dichloromethane is added, the layers are separated, and the lower layer is removed to obtain a clear solution; the mass ratio of zinc chloride, potassium chloroplatinite and stannous chloride is (0.1-0.7):1:(1-5); the mass ratio of tetrabutylammonium bromide to potassium chloroplatinite is 10.0-30.0:10.0-20.0; A solution of stannous chloride in tetrahydrofuran is added to the clear solution, and the mixture is stirred to obtain a mixed solution; the mass ratio of Pt, Zn and Sn is 1:0.5:3; A suspension of aluminum oxide in tetrahydrofuran is added to the mixed solution, and the mixture is stirred to obtain a solid; The solid is dried, and then calcined at a temperature of 500-600℃ under a mixed gas of H2 and Ar at a temperature increasing rate of 5-10℃ / min for 1-3h to obtain the Zn-regulated PtSn / Al2O3 catalyst.

2. A process for the preparation of a Zn-modulated PtSn / Al203 catalyst for the dehydrogenation of propane according to claim 1, characterized in that, The mass ratio of aluminum oxide to potassium chloroplatinite is 0.600:10.0-20.

0.

3. A Zn-modulated PtSn / Al203 catalyst for the dehydrogenation of propane, prepared according to the preparation method of claim 1, characterized by the fact that, The catalyst has a metal cluster size of 1-2nm.

4. Use of the Zn-regulated PtSn / Al2O3 catalyst prepared by the preparation method of claim 1 in the dehydrogenation of propane.

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