Isomerization Reaction of 1,1,2,2-Tetrafluoroethane on Chromia—A Study of the Active Sites on the Surface

Catalytic dehydrofluorination of 1,1,1,2-tetrafluoroethane to synthesize trifluoroethylene over a modified NiO/Al2O3 catalyst

“…† With an elevation in the reaction temperature, the selectivity to trifluoroethylene decreased from 100% to 96.8%, accompanied with the formation of CFHCFH, CF 2 HCF 3 and CF 2 HCFH 2 . The byproducts were derived from the pyrolysis and isomerization 31,32 of CF 3 CFH 2 at high temperature. When the dehydrofluorination of CF 3 CFH 2 was conducted at high temperatures (≥480 °C), the used catalysts turned black in a short time, indicating that serious coke or polymerization occurred over the catalysts.…”

Catalytic Dehydrofluorination of Hydrofluoroalkanes to Fluorinated Olifein Over Ni/AlF3 Catalysts

“…At 480 o C, selectivity of three catalysts is not much different, all above 98%. From Figure 1b), the selectivity of three catalysts to trifluoroethylene is gradually decreased as the reaction temperature increases, due to presence of byproduct CFH=CFH, CF2HCF3 and CF2HCFH2 derived from the cracking or isomerization of CF3CFH2 under the high temperature [14,15]. The temperature is also an important factor affecting the performance of the catalyst.…”

Characterization and Performance of CrO<SUB><EM>x</EM></SUB>-Y<SUB>2</SUB>O<SUB>3</SUB> Catalysts for the Synthesis of 1,1,1,2-Tetrafluoroethane

“…Therefore,UV鄄Visresultsindicatedthatthetransformationof Crspecies,whichiswellconsistentwiththeresultsobtainedby theXRDanalysis.IntheCrYFScatalysts,theappearanceofCr 3+ speciesindicatedthatpartialCr 6+ wasreducedduringthevapor鄄 phasefluorinationprocess. [10,16,27] .Inourpreviouswork [17] ,weconcludedthatduringtheactivationprocess,partialwelldispersed monochromate(CrO 3 )transformedtotheCrO x FyorCr(OH) x F y . Ithasalsobeenconcludedthatchromiumfluorideoxyfluoride CrO x F y orCr(OH) x F y speciesaretheactivesitesforthefluorina-tionofCF 3 CH 2 CltoCF 3 CH 2 F [28,29] .…”