Heterogeneous catalyzed synthesis of 1,1,1,2-tetrafluoroethane from 1,1,1,2-tetrachloroethane — thermodynamics and reaction pathways

Fluorination of dichlorodifluoromethane to synthesize tetrafluoromethane over Cr2O3–AlF3 catalyst

“…As claimed in the literature [10], the Cl/F exchange reaction of CCl 2 F 2 is generally thermodynamically possible but is kinetically hindered. Consequently, in order to obtain a considerable yield, it is necessary to use highly efficient catalysts to accelerate the reaction rate.…”

Solvent effects in the fluorination of 1,2-dichloro-1,1-difluoroethane (R-132b) to 2-chloro-1,1,1-trifluoroethane (R-133a)

“…If the good reactivity of R-131a is attributed to its ability to eliminate to a mechanistically active olefin (CFCl CHCl) then the question still remains as to why R-132b does not do the same. The elimination of HCl from R-131a becomes thermodynamically favorable above 58 8C, while the elimination of HCl from R-132b becomes favorable above 82 8C [7]. In either case, reaction conditions have been above those temperatures.…”

“…First, a molecule of HF adds across the TCE double bond to produce 1,1,2-dichloro-1-fluoroethane (R-131a). Second, direct fluorine-for-chlorine exchange converts R-131a to 1,2-dichloro-1, 1-difluoroethane (R-132b) [7][8][9]. The third reaction is another fluorine-for-chlorine exchange that converts R-132b to R-133a.…”

Manufacture of hydrofluorocarbons and hydrofluoroolefins as the CFCs-alternatives: from fundamental of catalytic reaction to commercialization

“…Cr2O3+6HF→2CrF3+3H2O, ∆rG θ =−68 kJ mol −1 (21) Al2O3+6HF→2AlF3+3H2O, ∆rG θ =−329 kJ mol −1 (22) F-Cr2O3催化剂的程序升温还原技术(TPR)、程序 升温氧化技术(TPO)表征结果表明, 活性与催化剂表 面可逆氧化态铬物种的浓度呈正比; 而X射线衍射 (XRD)、X射线光电子能谱(XPS) (图4)、Raman光谱 表征结果表明, 高价铬(>+3)生成的无定型CrFx、CrOxFy 或β-CrF3是氟化反应活性中心 [27,50~54] . Cr 3+ /AlF3负载型…”