Quenching of *UF6 (A state) by alkanes

The removal of *UF₆ (A state) molecules by selected alkanes has been investigated at 25°C. The following rate constants (units of 10¹¹ l/mol·sec) were evaluated: iso-C₄F₁₀, 0.0432 ± 0.0115; n-C₄F₁₀, 0.0764 ± 0.020; C₂F₆, 0.0192 ± 0.0052; CH₄, 0.0612 ± 0.0061; C₂H₆, 3.78 ± 0.60; C₃H₈, 5.08 ± 0.60; n-C₄H₁₀, 5.05 ± 0.78; iso-C₄H₁₀, 4.17 ± 1.15; neo-C₅H₁₂, 6.59 ± 0.93; CF₃? CH₃, 0.0385 ± 0.0056; CF₂H? CF₂H, 0.0729 ± 0.0074; and CF₂H? CFH₂, 0.149 ± 0.015. The perfluoro-alkane quenching of *UF₆ proceeds via a physical mechanism. The other alkane quenching reactions are consistent with a chemical mechanism also contributing in varying degrees which may involve removal of two hydrogens from the alkane.