Ce-doped nickel-aluminum spinel catalyst, and preparation method and application thereof
By loading a cerium source onto a nickel-aluminum spinel support to prepare a Ce-doped catalyst, the problem of catalyst deactivation due to sintering was solved, and the efficient conversion of fluorinated alkanes into fluorinated olefins was achieved, making it suitable for industrial applications.
Patent Information
- Application Number
- CN202410987341.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-23
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2044-07-23
AI Technical Summary
Existing catalysts are prone to coking and deactivation during the deHF removal reaction of fluorinated alkanes, resulting in decreased catalyst activity and making it difficult to meet the requirements for efficient conversion of fluorinated olefins.
Using nickel-aluminum spinel as a support, a Ce-doped nickel-aluminum spinel catalyst was prepared by loading a cerium source onto it. The interaction between Ce and the support was utilized to regulate the acidity and acidity of the catalyst, thereby improving the reaction activity and stability.
It achieves high activity and stability of the catalyst, simplifies the preparation process, is suitable for industrial production, has high conversion rate and selectivity, and has excellent anti-sintering properties.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of chemical catalysts, and particularly relates to a preparation method of a Ce-doped nickel-aluminum spinel catalyst and application thereof. BACKGROUND
[0002] Hydrofluorocarbons (HFCs) are a collective term for halogenated alkanes composed of hydrogen, fluorine and carbon, and are the third generation of refrigerants with the lowest ozone depletion potential (ODP) in the world. Hydrofluorocarbons have a high global warming potential (GWP), based on 100 years, for example, 1,1,1,2-tetrafluoroethane (HFC-134a) is 1300, 1,1,1,3,3-pentafluoropropane (HFC-245fa) is 820, and 1,1-difluoroethane (HFC-152a) is 124. The international community is working hard to control the use of hydrofluorocarbons (HFCs). At present, hydrofluoroalkenes (HFOs) are considered to be good substitutes for HFCs, which have the advantages of short atmospheric lifetime, zero ozone depletion potential (ODP) and low global warming potential (GWP).
[0003] The reaction of fluorine-containing alkanes (HFCs) to synthesize fluorine-containing alkenes (HFOs) is an endothermic reaction, so a high reaction temperature is required. Such a reaction mainly involves the breaking of C-F bonds, and highly corrosive byproduct HF is generated during pyrolysis. The formation of highly corrosive HF byproduct brings great challenges to the selection and design of catalysts. Therefore, for catalytic reactions involving HF, the selection of catalysts is often metal fluorides and other HF-resistant materials.
[0004] The application uses nickel-aluminum spinel as a carrier, and different cerium sources are loaded on the carrier to prepare a Ce-doped nickel-aluminum spinel catalyst. Due to the interaction between the carrier and the cerium source, the catalyst is not easy to sinter and deactivate, and the presence of cerium can regulate the acid amount and acidity of the catalyst, thereby improving the activity and stability of the reaction. SUMMARY
[0005] In view of the above carbon deposition and sintering phenomena existing in the existing catalysts, which lead to catalyst deactivation, the purpose of the application is to provide a preparation method of a Ce-doped nickel-aluminum spinel catalyst and application thereof.
[0006] The technical scheme adopted by the application is as follows:
[0007] The preparation method of the Ce-doped nickel-aluminum spinel catalyst comprises the following steps: dissolving a nickel source and an aluminum source in deionized water, fully stirring, then using a gel agent to regulate the pH value to be alkaline, heating and refluxing at a temperature of 50-90 DEG C for 10-40 h, then cooling to room temperature, filtering, drying, and calcining in an air atmosphere to obtain a NiAl spinel carrier, dipping the carrier into a cerium source solution, fully dipping, then drying, and then roasting in a muffle furnace to obtain the Ce-doped nickel-aluminum spinel catalyst.
[0008] Further, the nickel source is selected from at least one of Ni(NO3)2.6H2O, NiCl2, NiO, NiCO3 and (CH3COO)2Ni, and preferably is Ni(NO3)2.6H2O; and the aluminum source is selected from at least one of Al(NO3)3.9H2O, AlCl3, Al2O3 and (CH3COO)3Al, and preferably is Al(NO3)3.9H2O.
[0009] Further, the molar ratio of the nickel source and the aluminum source is 0.5-8:1, and preferably is 2-4:1.
[0010] Further, the total concentration of the nickel source and the aluminum source in the deionized water is 0.75-5 mol / L, the gel agent used is one of ethylenediamine, ammonia water and sodium hydroxide, and preferably is ethylenediamine; the pH value is regulated to 8-12 by using the gel agent, and preferably is 9-10.
[0011] Further, the temperature of the heating and refluxing reaction is 70-80 DEG C, and the reaction time is 20-25 h; the calcination for preparing the NiAl spinel carrier is performed in a muffle furnace, the calcination temperature is 600-900 DEG C, and preferably is 750-800 DEG C, and the calcination time is 1-4 h.
[0012] Further, the cerium source is selected from at least one of Ce(OH)3, CeO2, Ce(NO3)3.6H2O and CeCl3.7H2O, and preferably is Ce(NO3)3.6H2O; and the feeding ratio of the cerium source to the NiAl spinel carrier is 0.1-2 mmol:3 g.
[0013] Further, the roasting temperature after the cerium source is dipped onto the carrier is 500-700 DEG C, and preferably is 550-600 DEG C, and the roasting time is 1-3 h.
[0014] The application further provides application of the catalyst in a reaction for catalyzing gas-phase dehydrofluorination of a fluorine-containing alkane to prepare a fluorine-containing alkene, wherein the fluorine-containing alkane comprises at least one of 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane and 1,1,1,3,3-pentafluoropropane, the temperature of the catalytic reaction is 400-550 DEG C, and preferably is 450-500 DEG C, and the reaction pressure is normal pressure.
[0015] By adopting the above-mentioned technology, compared with the prior art, the beneficial effects of the present application are as follows:
[0016] 1) The present application takes NiAl spinel as a carrier, and a Ce-doped nickel aluminum spinel catalyst is prepared under the action of a cerium source. Due to the interaction between Ce and the carrier, the catalyst is not easy to sinter and deactivate, and the presence of cerium can regulate the acid amount and acidity of the catalyst, thereby improving the activity and stability of the reaction.
[0017] 2) The Ce-doped nickel aluminum spinel catalyst of the present application is prepared by a sol-gel method, which has the characteristics of simple preparation method, short preparation period, high yield and conversion rate of catalytic reaction, and simple operation, and belongs to an environmentally friendly material, and can be applied to industrial production. The catalyst synthesized by the method of the present application has high catalytic activity and stability in the reaction of preparing fluorine-containing olefins by removing HF from fluorine-containing alkanes.
[0018] 3) The catalyst prepared by the method of the present application shows extremely high activity and stability in the reaction of preparing fluorine-containing olefins (HFOs) by removing HF from fluorine-containing alkanes (HFCs) in the gas phase. The catalyst provided by the present application has the characteristics of simple preparation, high conversion rate, good selectivity, long service life and sintering resistance. DETAILED DESCRIPTION
[0019] The present application will be further described below in conjunction with specific examples, but the scope of protection of the present application is not limited thereto.
[0020] Example 1
[0021] 0.2 mol of Ni(NO3)2·6H2O and 0.05 mol of Al(NO3)2·9H2O were weighed and dissolved in 100 mL of water, and were stirred thoroughly, then ethylenediamine was added to adjust the pH of the solution to 9, and the sample was stirred for 30 min. The stirred sample was heated to reflux at 80℃ for 24 h, then was cooled to room temperature and filtered. The product was dried at 100℃ for 24 h, and finally was calcined at 800℃ in a muffle furnace for 2 h to obtain a carrier of NiAl spinel. 3 g of the carrier was impregnated in a cerium nitrate solution of 0.1 mmol (the solution volume was 10 mL, the same below), and the sample was dried overnight, then was calcined at 600℃ in a muffle furnace for 2 h, was cooled to room temperature, was crushed, and finally was sieved with a standard sieve of 20-40 meshes. The sample was recorded as 0.5Ce / Ni4Al.
[0022] The 0.5Ce / Ni4Al catalyst prepared above was used to prepare fluorine-containing olefin of trifluoroethylene by removing HF from 1,1,1,2-tetrafluoroethane (HFC-134a), and the reaction formula was as follows:
[0023]
[0024] Reaction conditions: 2ml catalyst was packed into a nickel tube on a fixed bed reactor, N2 and HFC-134a were introduced, N2 flow was controlled at 20ml / min, HFC-134a flow was controlled at 10ml / min, total gas hourly space velocity was 900h -1 Reaction temperature was 450°C, reaction was carried out under normal pressure for 5h and sampled for analysis. The results were: the conversion of reactant 1,1,1,2-tetrafluoroethane (HFC-134a) was 45.1%, the selectivity of trifluoroethylene was as high as 100%, after 30h reaction, the conversion of reactant was 45.7% and the selectivity of trifluoroethylene was 100%.
[0025] Example 2
[0026] The preparation steps of the catalyst in Example 2 were repeated in Example 1, except that "no cerium nitrate was impregnated on the NiAl spinel carrier", and the sample was recorded as 0Ce / Ni4Al, and other conditions were unchanged.
[0027] The 0Ce / Ni4Al catalyst described in Example 2 was used in the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) dehydrofluorination to prepare trifluoroethylene, and the reaction conditions were repeated in Example 1. The results were: the conversion of reactant 1,1,1,2-tetrafluoroethane (HFC-134a) was 38.6%, the selectivity of trifluoroethylene was as high as 100%, after 30h reaction, the conversion of reactant was 39.2% and the selectivity of trifluoroethylene was 100%.
[0028] Example 3
[0029] The preparation steps of the catalyst in Example 3 were repeated in Example 1, except that "3g of the carrier was impregnated into a 2mmol cerium nitrate solution", and the sample was recorded as 10Ce / Ni4Al, and other conditions were unchanged.
[0030] The catalyst in Example 3 was applied to the reaction of HFC-134a dehydrofluorination to prepare trifluoroethylene, and the reaction conditions were repeated in Example 1. The results were: the conversion of reactant 1,1,1,2-tetrafluoroethane (HFC-134a) was 42.2%, the selectivity of trifluoroethylene was as high as 100%, after 30h reaction, the conversion of reactant was 42.9% and the selectivity of trifluoroethylene was 100%.
[0031] According to NH3-TPD, it was found that the acid amount was reduced when the cerium content was too high compared with 0.5Ce. This reaction was closely related to the acid amount.
[0032] Example 4
[0033] Example 4 Catalyst Preparation Step repeats Example 1, the only difference is that "weigh 3g carrier impregnated into 0.1mmol cerium chloride solution", the prepared catalyst is recorded as 0.5CeCl3 / Ni4Al catalyst, other conditions remain unchanged.
[0034] Example 4 Catalyst is applied to the reaction of HFC-134a de-HF to prepare trifluoroethylene, the reaction conditions repeat Example 1, and the sample is analyzed after 5h of normal pressure reaction. The results are: the conversion rate of the reactant 1,1,1,2-tetrafluoroethane (HFC-134a) is 41.7%, and the selectivity of trifluoroethylene is as high as 100%. The conversion rate of the reactant is 41.5% and the selectivity of trifluoroethylene is 100% after 30h of reaction.
[0035] Example 5
[0036] Example 5 Catalyst Preparation Step repeats Example 1, the only difference is that "weigh 3g carrier impregnated into 0.1mmol cerium oxide solution", other conditions remain unchanged. The prepared catalyst is recorded as 0.5CeO2 / Ni4Al catalyst.
[0037] Example 5 Catalyst is applied to the reaction of HFC-134a de-HF to prepare trifluoroethylene, the reaction conditions repeat Example 1, and the sample is analyzed after 5h of normal pressure reaction. The results are: the conversion rate of the reactant 1,1,1,2-tetrafluoroethane (HFC-134a) is 41.7%, and the selectivity of trifluoroethylene is as high as 100%. The conversion rate of the reactant is 41.5% and the selectivity of trifluoroethylene is 100% after 30h of reaction.
[0038] Example 6
[0039] Example 6 Catalyst Preparation repeats Example 5.
[0040] Example 6 0.5CeO2 / Ni4Al catalyst prepared is used for the reaction of 1,1-difluoroethane (HFC-152a) de-HF to prepare fluoroethylene, and the reaction formula is as follows:
[0041]
[0042] The reaction conditions are: 2ml of catalyst is filled into a nickel tube on a fixed bed reactor, N2 and HFC-152a are introduced, the flow rate of N2 is controlled at 20ml / min, the flow rate of HFC-152a is controlled at 10ml / min, the total space velocity of the mixed gas is 900h -1 , the reaction temperature is 450℃, and the sample is analyzed after 5h of normal pressure reaction. The results are: the conversion rate of the reactant HFC-152a is 60.5%, and the selectivity of fluoroethylene is as high as 98.1%. The conversion rate of the reactant is 60.1% and the selectivity of fluoroethylene is 99.3% after 30h of reaction.
[0043] Example 7
[0044] The catalyst of Example 7 was prepared by repeating the preparation procedure of Example 1, except that the temperature of the heating reflux was replaced by 60°C, and the sample was labeled as 0.5Ce / Ni4Al-60. The other conditions were the same as those of Example 1.
[0045] The 0.5Ce / Ni4Al-60 catalyst of Example 7 was used in the reaction of dehydrofluorination of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce 1,1,2-trifluoroethylene, and the reaction conditions were repeated as in Example 1. The sample was analyzed after 5 h of reaction under normal pressure. The results were as follows: the conversion of the reactant 1,1,1,2-tetrafluoroethane was 25.8%, and the selectivity of TrFE was as high as 90%. The sample was analyzed after 30 h of reaction, and the conversion of the reactant was 22.9% and the selectivity of TrFE was 93%.
[0046] Example 8
[0047] The catalyst of Example 8 was prepared by repeating the preparation procedure of Example 1.
[0048] The catalyst of Example 8 was used in the reaction of dehydrofluorination of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce 1,1,2-trifluoroethylene, and the reaction conditions were repeated as in Example 1. The sample was analyzed after 5 h of reaction under normal pressure. The results were as follows: the conversion of the reactant 1,1,1,2-tetrafluoroethane was 25.8%, and the selectivity of TrFE was as high as 90%. The sample was analyzed after 30 h of reaction, and the conversion of the reactant was 22.9% and the selectivity of TrFE was 93%.
[0049] Example 9
[0050] The catalyst of Example 9 was prepared by repeating the preparation procedure of Example 2.
[0051] The catalyst of Example 9 was used in the reaction of dehydrofluorination of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce 1,1,2-trifluoroethylene, and the reaction conditions were repeated as in Example 1. The sample was analyzed after 5 h of reaction under normal pressure. The results were as follows: the conversion of the reactant 1,1,1,2-tetrafluoroethane was 25.8%, and the selectivity of TrFE was as high as 90%. The sample was analyzed after 30 h of reaction, and the conversion of the reactant was 22.9% and the selectivity of TrFE was 93%.
[0052]
[0053] The reaction conditions were as follows: 2 ml of the catalyst was filled into a nickel tube on a fixed-bed reactor, N2 and HFC-245fa were introduced, the flow rate of N2 was controlled at 20 ml / min, the flow rate of HFC-245fa was controlled at 10 ml / min, and the total space velocity of the mixed gas was 900 h-1. -1, the reaction temperature was 450°C, and the reaction was sampled and analyzed after 5 hours of reaction under normal pressure. The results were as follows: the conversion rate of the reactant 1,1,1,3,3-pentafluoropropane was 56.9%, and the selectivity of HFO-1234ze was as high as 99.8%; the reaction was sampled and analyzed after 30 hours of reaction, and the conversion rate of the reactant was 58.1%, and the selectivity of HFO-1234ze was 100%.
[0054] Example 10
[0055] The preparation of the catalyst of Example 10 was repeated with Example 1.
[0056] The catalyst of Example 10 was used to catalyze the cracking of 1,1,1,3,3-pentafluoropropane (HFC-245fa) to prepare 1,3,3,3-tetrafluoropropene (HFO-1234ze), and the reaction conditions were repeated with Example 9. The reaction was sampled and analyzed after 5 hours of reaction under normal pressure. The results were as follows: the conversion rate of the reactant HFC-245fa was 77.5%, and the selectivity of HFO-1234ze was as high as 99.5%; the reaction was sampled and analyzed after 30 hours of reaction, and the conversion rate of the reactant was 78.1%, and the selectivity of HFO-1234ze was 99.9%.
[0057] Example 11
[0058] The preparation steps of the catalyst of Example 11 were repeated with Example 3.
[0059] The catalyst of Example 11 was used to catalyze the cracking of 1,1,1,3,3-pentafluoropropane (HFC-245fa) to prepare 1,3,3,3-tetrafluoropropene (HFO-1234ze), and the reaction conditions were repeated with Example 9. The reaction was sampled and analyzed after 5 hours of reaction under normal pressure. The results were as follows: the conversion rate of the reactant HFC-245fa was 72.3%, and the selectivity of HFO-1234ze was as high as 89.6%; the reaction was sampled and analyzed after 30 hours of reaction, and the conversion rate of the reactant was 73.2%, and the selectivity of HFO-1234ze was 90.1%.
[0060] Example 12
[0061] The preparation steps of the catalyst of Example 12 were repeated with Example 1, except that the molar ratio of nickel nitrate to aluminum nitrate was changed to 0.5 (the amount of nickel nitrate was changed, and the amount of aluminum nitrate was unchanged), and the prepared catalyst was recorded as 0.5Ce / Ni 0.5 Al catalyst, and other conditions were unchanged.
[0062] Example 12 Catalyst for the preparation of 1,3,3,3-tetrafluoropropene (HFO-1234ze) by the cracking of 1,1,1,3,3-pentafluoropropane (HFC-245fa), the reaction condition is repeated in Example 9, the reaction is sampled and analyzed after 5h. The results are as follows: the conversion of the reactant HFC-245fa is 51.6%, the selectivity of HFO-1234ze is as high as 93.7%, the conversion of the reactant is 52.1% and the selectivity of HFO-1234ze is 95.2% after the reaction is sampled and analyzed after 30h.
[0063] Example 13
[0064] The preparation steps of the catalyst in Example 13 are repeated in Example 1, the only difference is that "the molar ratio of nickel nitrate and aluminum nitrate is changed to 8 (the amount of nickel nitrate is changed, the amount of aluminum nitrate is unchanged)", the prepared catalyst is recorded as 0.5Ce / Ni8Al catalyst, and other conditions are unchanged.
[0065] Example 13 Catalyst for the preparation of fluoroethylene by the dehydrofluorination of 1,1-difluoroethane (HFC-152a), the reaction formula is as follows:
[0066]
[0067] Example 13 Catalyst for the preparation of fluoroethylene by the dehydrofluorination of 1,1-difluoroethane (HFC-152a), the reaction condition is repeated in Example 6, the results are as follows: the conversion of the reactant HFC-152a is 41.1%, the selectivity of fluoroethylene is as high as 100%, the conversion of the reactant is 42.4% and the selectivity of fluoroethylene is 100% after the reaction is sampled and analyzed after 30h.
[0068] Example 14
[0069] The preparation steps of the catalyst in Example 14 are repeated in Example 1, the only difference is that "the molar ratio of nickel nitrate and aluminum nitrate is changed to 0.5" (the molar amount of aluminum nitrate is unchanged, the molar amount of nickel nitrate is changed), the prepared catalyst is recorded as 0.5Ce / Ni 0.5 Al catalyst, and other conditions are unchanged.
[0070] The 0.5Ce / Ni 0.5 Al catalyst prepared above is used for the preparation of 1,1,2-trifluoroethene by the dehydrofluorination of 1,1,1,2-tetrafluoroethane (HFC-134a), the reaction formula is as follows:
[0071]
[0072] Example 14 Catalyst for the reaction of 1,1,1,2-tetrafluoroethane (HFC- 134a) to prepare fluoroethylene by removing HF, the reaction conditions are repeated in Example 1, the results are: the conversion of the reactant HFC-134a is 33.8%, the selectivity of TrFE is as high as 100%, the conversion of the reactant is 34.1% and the selectivity of TrFE is 100% after sampling analysis for 30 h.
[0073] Example 15
[0074] Example 15 The preparation steps of the catalyst are repeated in Example 1, the only difference is that the molar ratio of nickel nitrate and aluminum nitrate is changed to 8 (where the molar amount of aluminum nitrate is unchanged, and the molar amount of nickel nitrate is changed), and the prepared catalyst is recorded as 0.5Ce / Ni8Al catalyst, and other conditions remain unchanged.
[0075] The above prepared 0.5Ce / Ni8Al catalyst is used for the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to prepare fluoroethylene by removing HF, and the reaction formula is as follows:
[0076]
[0077] Example 14 Catalyst for the reaction of 1,1,1,2-tetrafluoroethane (HFC- 134a) to prepare fluoroethylene by removing HF, the reaction conditions are repeated in Example 1. Sampling analysis is performed after 5 h of normal pressure reaction. The results are: the conversion of the reactant HFC-134a is 26.2%, the selectivity of TrFE is as high as 100%, the conversion of the reactant is 28.1% and the selectivity of TrFE is 100% after sampling analysis for 30 h.
[0078] Example 16
[0079] The commercial NiAl2O4 is weighed and calcined at 800°C for 2 h in a muffle furnace, and finally sieved with a standard sieve of 20-40 mesh to obtain S-NiAl2O4 catalyst.
[0080] The above prepared S-NiAl2O4 catalyst is used for the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to prepare fluoroethylene by removing HF, and the reaction formula is as follows:
[0081]
[0082] Example 16 The catalyst of Example 16 was used in the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce trifluoroethylene by removing HF, and the reaction conditions were repeated as in Example 1. The sample was analyzed after 5h of reaction under normal pressure. The results were as follows: the conversion of the reactant 1,1,1,2-tetrafluoroethane was 15.1%, and the selectivity of TrFE was as high as 87%. The sample was analyzed after 30h of reaction, and the conversion of the reactant was 16.7% and the selectivity of TrFE was 89%.
[0083] Example 17
[0084] The preparation steps of the catalyst of Example 17 were repeated as in Example 1, except that "ammonia was used to adjust pH=9", and the sample was recorded as 0.5Ce / Ni4Al-NH3, and other conditions were unchanged.
[0085] The catalyst of Example 17 was used in the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce trifluoroethylene by removing HF, and the reaction conditions were repeated as in Example 1. The sample was analyzed after 5h of reaction under normal pressure. The results were as follows: the conversion of the reactant 1,1,1,2-tetrafluoroethane (HFC-134a) was 28.6%, and the selectivity of TrFE was as high as 96%. The sample was analyzed after 30h of reaction, and the conversion of the reactant was 29.2% and the selectivity of TrFE was 94%.
[0086] Example 18
[0087] The preparation steps of the catalyst of Example 18 were repeated as in Example 1, except that "sodium hydroxide was used to adjust pH=9", and the sample was recorded as 0.5Ce / Ni4Al-NaOH, and other conditions were unchanged.
[0088] The catalyst of Example 18 was used in the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce trifluoroethylene by removing HF, and the reaction conditions were repeated as in Example 1. The sample was analyzed after 5h of reaction under normal pressure. The results were as follows: the conversion of the reactant 1,1,1,2-tetrafluoroethane was 17.6%, and the selectivity of TrFE was as high as 90%. The sample was analyzed after 30h of reaction, and the conversion of the reactant was 19.2% and the selectivity of TrFE was 88%.
[0089] Example 19
[0090] The preparation steps of the catalyst of Example 19 were repeated as in Example 1, except that "nickel nitrate was replaced by cobalt nitrate of equal molar quantity", and the sample was recorded as 0.5Ce / Co4Al, and other conditions were unchanged.
[0091] The 0.5Ce / Co4Al catalyst described in Example 19 was used in the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce 1,1,2-trifluoroethylene by removing HF, the reaction conditions were repeated in Example 1, and the sample was analyzed after 5 h of reaction under normal pressure. The results were as follows: the conversion rate of the reactant 1,1,1,2-tetrafluoroethane was 27.6%, and the selectivity of TrFE was as high as 100%, and the conversion rate of the reactant was 29.3% and the selectivity of TrFE was 100% after 30 h of reaction.
[0092] Example 20
[0093] The preparation steps of the catalyst in Example 20 were repeated in Example 1, except that the calcination temperature for preparing the NiAl spinel carrier was replaced by 600°C, and the sample was recorded as 0.5Ce / Ni4Al-600, and the other conditions were unchanged.
[0094] The 0.5Ce / Co4Al-600 catalyst described in Example 20 was used in the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce 1,1,2-trifluoroethylene by removing HF, the reaction conditions were repeated in Example 1, and the sample was analyzed after 5 h of reaction under normal pressure. The results were as follows: the conversion rate of the reactant 1,1,1,2-tetrafluoroethane was 37.6%, and the selectivity of TrFE was as high as 100%, and the conversion rate of the reactant was 37.3% and the selectivity of TrFE was 100% after 30 h of reaction.
[0095] Example 21
[0096] The preparation steps of the catalyst in Example 21 were repeated in Example 1, except that the calcination temperature for preparing the NiAl spinel carrier was replaced by 900°C, and the sample was recorded as 0.5Ce / Ni4Al-900, and the other conditions were unchanged.
[0097] The 0.5Ce / Co4Al-900 catalyst described in Example 21 was used in the reaction of 1,1,1,2-tetrafluoroethane (HFC-134a) to produce 1,1,2-trifluoroethylene by removing HF, the reaction conditions were repeated in Example 1, and the sample was analyzed after 5 h of reaction under normal pressure. The results were as follows: the conversion rate of the reactant 1,1,1,2-tetrafluoroethane was 33%, and the selectivity of TrFE was as high as 100%, and the conversion rate of the reactant was 32.2% and the selectivity of TrFE was 100% after 30 h of reaction.
[0098] The content described in the specification is only a list of forms of the inventive concept, and the protection scope of the present application should not be regarded as limited to the specific forms stated in the examples.
Claims
1. The application of a Ce-doped nickel-aluminum spinel catalyst in the catalytic gas-phase deHF removal of fluorinated alkanes to prepare fluorinated olefins, characterized in that... The preparation method of the catalyst includes the following steps: dissolving a nickel source and an aluminum source in deionized water, stirring thoroughly, then adjusting the pH value to alkaline using a gelling agent, heating and refluxing at 50-90℃ for 10-40h, then cooling to room temperature, filtering, drying, and calcining in air atmosphere to obtain a NiAl spinel support, impregnating the support in a cerium source solution, drying after thorough impregnation, and then calcining in a muffle furnace to obtain the Ce-doped nickel-aluminum spinel catalyst; The molar ratio of nickel source to aluminum source is 0.5-8:1; The cerium source is selected from at least one of Ce(OH)3, CeO2, Ce(NO3)3·6H2O or CeCl3·7H2O; the feeding ratio of the cerium source to the NiAl spinel support is 0.1-2 mmol:3g.
2. The application as described in claim 1, characterized in that... The nickel source is selected from at least one of Ni(NO3)2·6H2O, NiCl2, NiO, NiCO3, and (CH3COO)2Ni, and the aluminum source is selected from at least one of Al(NO3)3·9H2O, AlCl3, Al2O3, and (CH3COO)3Al.
3. The application as described in claim 2, characterized in that... The nickel source was selected from Ni(NO3)2·6H2O, and the aluminum source was selected from Al(NO3)3·9H2O.
4. The application as described in claim 1, characterized in that... The molar ratio of nickel source to aluminum source is 2-4:
1.
5. The application as described in claim 1, characterized in that... The total concentration of nickel and aluminum sources in deionized water is 0.75-5 mol / L. The gelling agent used is one of ethylenediamine, ammonia, or sodium hydroxide. The pH value is adjusted to 8-12 using the gelling agent.
6. The application as described in claim 5, characterized in that... The gelling agent used was ethylenediamine; the pH value was adjusted to 9-10 using the gelling agent.
7. The application as described in claim 1, characterized in that... The heating reflux reaction is carried out at a temperature of 70-80℃ for 20-25 hours; the NiAl spinel support is prepared by calcination in a muffle furnace at a temperature of 600-900℃ for 1-4 hours.
8. The application as described in claim 7, characterized in that... The calcination temperature is 750-800℃.
9. The application as described in claim 1, characterized in that... The cerium source is selected from Ce(NO3)3·6H2O.
10. The application as described in claim 1, characterized in that... The calcination temperature after the cerium source is impregnated onto the carrier is 500-700℃, and the calcination time is 1-3h.
11. The application as described in claim 10, characterized in that... The calcination temperature after the cerium source is impregnated onto the carrier is 550-600℃.
12. The application as described in claim 1, characterized in that... The fluorinated alkane includes at least one of 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane, and 1,1,1,3,3-pentafluoropropane. The catalytic reaction temperature is 400~550 °C, and the reaction pressure is atmospheric pressure.
13. The application as described in claim 12, characterized in that... The temperature for the catalytic reaction is 450-500℃.