Triethylsilane-loaded aluminium chlorofluoride

The recently reported surface modification of aluminium chlorofluoride (ACF) by interaction with triethylsilane yields a promising hydrodefluorination catalyst (ACF- Sil ) the activity of which was assigned to surface-bound entities of the type ACF···H-SiEt 3 . Their silylium ion-like character was proposed to initiate the C–F activation step for small hydrofluorocarbon (HFC) molecules thus mediating the hydrodefluorination reaction. In a Pulse TA ® study, the silane interaction with the catalyst precursor was followed by injections of Et 3 SiH onto ACF yielding a surface coverage of 0.13 mol% Et 3 SiH. No HF formation indicating a possible side reaction was observed. Afterwards, the reactions of the modified ACF- Sil with HFC’s such as CH 3 F, CH 2 F 2 , α,α,α -trifluorotoluene, or α,α,α -trifluoroethylbenzene were investigated by applying the same isothermal (50 °C) measuring regime. The PTA curves could be evaluated via the appearance of distinct mass numbers in the case of CH 2 F 2 and α,α,α -trifluorotoluene or, in the case of CH 3 F, by comparing selected peak area ratios for proving correspondingly the methane formation. α,α,α -trifluoroethylbenzene did not show any interaction with ACF- Sil under the chosen conditions.