Solution combustion synthesis of nano-chromia as catalyst for the dehydrofluorination of 1,1-difluoroethane

Han, Wenfeng; Wang, Zhikun; Li, Xiaojuan; Tang, Haodong; Xi, Miao; Li, Ying; Liu, Huazhang

doi:10.1007/s10853-016-0313-x

Cited by 23 publications

(21 citation statements)

References 44 publications

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“…Hence, we suggest that the particle size or crystal size of a barium catalyst plays a major role in the catalytic performance. Similar results were also confirmed for Cr2O3 catalysts for the dehydrofluorination of 1,1-difluoroethane [37].…”

Section: Resultssupporting

confidence: 84%

Facile Preparation of BaClxFy for the Catalytic Dehydrochlorination of 1-Chloro-1,1-Difluoroethane to Vinylidene Fluoride

Han

Liu

et al. 2020

Catalysts

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BaClxFy as well as BaF2 and BaClF catalysts were prepared by solid-state reaction at room temperature with Ba(OH)2 as the precursor and NH4F/NH4Cl as the F and Cl sources. The catalysts were applied for the dehydrochlorination of 1-chloro-1,1-difluoroethane to vinylidene fluoride at 350 °C. The industrial manufacture of vinylidene fluoride (VDF) is carried out at 600–700 °C, whereas the BaClxFy catalysts provided a promising pathway to produce VDF at much lower temperatures. Unfortunately, the selectivity of VDF over BaF2 decreased from 94% to 84% along with the deactivation of the BaF2 catalyst monotonically. In the presence of small amounts of Cl in BaF2, stabilized selectivity was achieved. Over BaCl0.05F0.95, BaCl0.1F0.9 and BaCl0.25F0.75, no decrease in VDF selectivity was observed. Clearly, the presence of small amounts Cl during solid-state preparation inhibited the growth of BaF2 crystalline significantly. Far smaller particles were achieved. The particle size, or more precisely, the crystal size of the barium catalyst played a major role in the catalytic performance. In addition to the crystal growth, the presence of small amounts of Cl during catalyst preparation changed the chemical state of Ba, and therefore the adsorption and activation of the C–Cl bond for HCFC-142b were altered.

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Section: Resultssupporting

confidence: 84%

Facile Preparation of BaClxFy for the Catalytic Dehydrochlorination of 1-Chloro-1,1-Difluoroethane to Vinylidene Fluoride

Han

Liu

et al. 2020

Catalysts

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“…In Figure 6 c) micrographs nano-metric particles and filaments (i.e minor at 1 m), were identified, this is consistent with TEM micrographs of calcined powders presented in Figure 7 c). Similar superficial morphologies were observed in powders obtained by solution combustion synthesis [4].The morphologies of Cr2O3 catalysts prepared by solution combustion synthesis with glycine as fuel is formed in relatively uniform flakes or flat particles, while commercial Cr2O3 shows irregular particles with sizes ranging from 120 nm to 3 m [26]. Chromium oxide nanoparticles have been synthesized using chromium nitrite and sodium oleate resulted in rice grain morphology an approximate length of 100 nm [2].…”

Section: Resultsmentioning

confidence: 77%

“…Various techniques have been developed for the synthesis of Cr2O3 nanoparticles, such as: thermal decomposition [11,12], sol-gel [13][14][15], hydrothermal method [1, 5, [16][17], solvothermal method [3,18], thermal process [19][20][21] microwave irradiation method [22], precipitation method [6,23], magnetronsupttering [24], self-assembly-like method [8], precipitation-gelation method [25], and combustion solution method using glycine [4, [26][27] and ethylenediaminetetraacetic acid (Edta), as fuels [28]. The use of new fuels has not been found in specific literature.…”

Section: Introductionmentioning

confidence: 99%

Estudio de las propiedades, estructurales, morfológicas y ópticas de nanopartículas de Cr2O3 sintetizadas por procesos de combustión de un solo paso y diferentes combustibles

et al. 2019

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RESUMEN Esta investigación presenta un nuevo método de síntesis de un solo paso para obtener Cr2O3 nanoestructurado a partir de una solución de nitrato de cromo y un combustible como ácido aspártico, o lisina, o trihidroximetilaminometano, o etilendiaminotetraacético. Una vez obtenido los polvos fueron calcinados a 500ºC. Luego se caracterizaron mediante difracción de rayos X (DRX), microscopía electrónica de barrido (MEB), microscopía electrónica de transmisión (TEM), espectroscopía infrarroja por transformada de Fourier (FTIR), espectroscopía por UV-Visible y técnicas de Brunauer–Emmett–Teller (BET). Estos polvos serán utilizados en superficies absorbedoras como cermts o pinturas selectivas solares. En las cenizas y los polvos calcinados obtenidos se identificó la estructura cristalina del Cr2O3, correspondiente al sistema romboédrico y al grupo espacial R-3c. El tamaño promedio de cristalita de los productos obtenidos estuvo entre 29 y 45 nm, donde para las cenizas el tamaño fue menor en comparación a los polvos obtenidos para todos los combustibles utilizados. Es probable que para un incremento de la temperatura el tamaño de cristalita crezca. Un área específica de 167 m2/g fue determinada para las cenizas obtenidas con ácido aspártico. Este fue el mayor valor observado en la literatura específica y podría utilizarse para reacciones de catálisis, mientras que el resto de los valores obtenidos para las cenizas fue mayor en comparación a los polvos calcinados para todos los combustibles. El tamaño promedio de partícula observado a través de TEM resultó entre 50 y 100 nm aproximadamente. La energía de Band Gap determinada resultó entre 3.055 eV y 3.078 eV, esta variable aumenta suavemente con la temperatura de calcinación. Para confirmar esta tendencia se deberían realizar mayor cantidad de experimentos.

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“…However, conventional AlF 3 catalyst is easy to be deposited carbon or coked on the surface resulting in deactivation, attributing to the strong Lewis acid sites, and thus have the low catalytic lifetime restricting its industrial application. The efforts to improve the catalytic stability and adjust the surface acidity of AlF 3 include nano preparation method,, combustion synthesis, template method, and metal additive method . A facile sol‐gel synthesis of nano α‐AlF 3 , which can improve the thermostability of AlF 3 , and show highly active catalyst for dehydrofluorination of hydrofluorocarbons due to the large Lewis acidic amounts .…”

Section: Introductionmentioning

confidence: 99%

A Novel Ni/NiF₂‐AlF₃ Catalyst with Mild‐Strength Lewis Acid Sites for Dehydrofluorination of 1, 1, 1, 2‐Tetrafluoroethane to Synthesize Trifluoroethylene

Liu

et al. 2019

ChemistrySelect

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A novel Ni/NiF2‐AlF3 catalyst was prepared by impregnation and following vapor hydrofluorination, and it was used to dehydrofluorination of tetrafluoroethane to trifluoroethylene. BET, SEM, XRD, XPS, NH3‐TPD and Py‐IR techniques were employed to characterize the Ni/NiF2‐AlF3 catalysts. Based on the NH3‐TPD results, it was interestingly found that the strong acidic sites of Ni/NiF2‐AlF3 catalyst transformed into the mid‐strength acidic sites with the increase of Ni loading, attributing to the roles of Ni on the catalyst surface. Compared with the NiF2‐AlF3 catalyst, the added Ni particles can improve the catalyst activity and stability for dehydrofluorination of 1, 1, 1, 2‐tetrafluoroethane. The best performance was obtained at Al/Ni=2 over the Ni/NiF2‐AlF3 catalyst, with high trifluoroethylene selectivity(99%) and CF3CFH2 conversion of 21.3%, after the reaction for 20 h on‐time stream at 500 °C, which showed the better application possibility as a heterogeneous dehydrofluorination catalyst. It was suggested that catalytic performance was related with the mid‐strength Lewis acidity on the catalyst surface. And the Ni/NiF2‐AlF3 catalyst (Al/Ni=2) possessed the good catalytic stability due to the mild‐strength Lewis acid sites.

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Solution combustion synthesis of nano-chromia as catalyst for the dehydrofluorination of 1,1-difluoroethane

Cited by 23 publications

References 44 publications

Facile Preparation of BaClxFy for the Catalytic Dehydrochlorination of 1-Chloro-1,1-Difluoroethane to Vinylidene Fluoride

Facile Preparation of BaClxFy for the Catalytic Dehydrochlorination of 1-Chloro-1,1-Difluoroethane to Vinylidene Fluoride

Estudio de las propiedades, estructurales, morfológicas y ópticas de nanopartículas de Cr2O3 sintetizadas por procesos de combustión de un solo paso y diferentes combustibles

A Novel Ni/NiF₂‐AlF₃ Catalyst with Mild‐Strength Lewis Acid Sites for Dehydrofluorination of 1, 1, 1, 2‐Tetrafluoroethane to Synthesize Trifluoroethylene

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Solution combustion synthesis of nano-chromia as catalyst for the dehydrofluorination of 1,1-difluoroethane

Cited by 23 publications

References 44 publications

Facile Preparation of BaClxFy for the Catalytic Dehydrochlorination of 1-Chloro-1,1-Difluoroethane to Vinylidene Fluoride

Facile Preparation of BaClxFy for the Catalytic Dehydrochlorination of 1-Chloro-1,1-Difluoroethane to Vinylidene Fluoride

Estudio de las propiedades, estructurales, morfológicas y ópticas de nanopartículas de Cr2O3 sintetizadas por procesos de combustión de un solo paso y diferentes combustibles

A Novel Ni/NiF2‐AlF3 Catalyst with Mild‐Strength Lewis Acid Sites for Dehydrofluorination of 1, 1, 1, 2‐Tetrafluoroethane to Synthesize Trifluoroethylene

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A Novel Ni/NiF₂‐AlF₃ Catalyst with Mild‐Strength Lewis Acid Sites for Dehydrofluorination of 1, 1, 1, 2‐Tetrafluoroethane to Synthesize Trifluoroethylene