The reaction of CF2Cl2 with gas-phase hydrated electrons

Abstract

The reaction of dichlorodifluoromethane (CF₂Cl₂) with hydrated electrons (H₂O)_n⁻ (n = 30–86) in the gas phase was studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The hydrated electron reacts with CF₂Cl₂, forming (H₂O)_mCl⁻ with a rate constant of (8.6 ± 2.2) × 10⁻¹⁰ cm³ s⁻¹, corresponding to an efficiency of 57 ± 15%. The reaction enthalpy was determined using nanocalorimetry, revealing a strongly exothermic reaction with ΔH_r(CF₂Cl₂, 298 K) = −208 ± 41 kJ mol⁻¹. The combination of the measured reaction enthalpy with thermochemical data from the condensed phase yields a C–Cl bond dissociation enthalpy (BDE) ΔH_C–Cl(CF₂Cl₂, 298 K) = 355 ± 41 kJ mol⁻¹ that agrees within error limits with the predicted values from quantum chemical calculations and published BDEs.