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Aqueous bromine atoms were produced by laser flash photolysis of 1,2-dibromoethane at 248 nm in s... more Aqueous bromine atoms were produced by laser flash photolysis of 1,2-dibromoethane at 248 nm in solutions containing bromide ions. Forward and reverse rate constants of the title reaction were determined as functions of temperature. An analysis of potential sources of systematic errors shows that the measured forward and reverse rate constants have relative uncertainties ((σ k /k) of ∼10 and ∼25%, respectively, over the temperature range from 10.5 to 50°C. The Arrhenius parameters are (k f ( 10%) ) 5.1 × 10 12 exp (-1812/T) M -1 s -1 and (k r ( 25%) ) 2.5 × 10 10 exp (-4068/T) s -1 . The equilibrium constant is found from the ratio of k f /k r : (K eq ( 30%) ) 2.0 × 10 2 exp (2256/T) M -1 or (3.9 ( 1.2) × 10 5 M -1 at 298 K. The reaction entropy and enthalpy are ∆S R°) 44 ( 6 J mol -1 K -1 and ∆H R°) -19 ( 2 kJ mol -1 , respectively. The corresponding reaction reduction potential is ∆E°) 0.33 ( 0.01 V, in very good agreement with that calculated from half-cell potentials. In addition, preliminary rate constants for Br 2 -• + Br 2 -• f Br 3 -+ Brand the hydrogen abstraction reaction (Br • + BrCH 2 CH 2 Br f • CBrH-CH 2 -Br + H + + Br -) are reported.

The Journal of Physical …, Jan 1, 1977

International Journal of Chemical Kinetics, Jan 1, 2001

Aqueous bromine atoms were produced by laser flash photolysis of 1,2-dibromoethane at 248 nm in s... more Aqueous bromine atoms were produced by laser flash photolysis of 1,2-dibromoethane at 248 nm in solutions containing bromide ions. Forward and reverse rate constants of the title reaction were determined as functions of temperature. An analysis of potential sources of systematic errors shows that the measured forward and reverse rate constants have relative uncertainties ((σ k /k) of ∼10 and ∼25%, respectively, over the temperature range from 10.5 to 50°C. The Arrhenius parameters are (k f ( 10%) ) 5.1 × 10 12 exp (-1812/T) M -1 s -1 and (k r ( 25%) ) 2.5 × 10 10 exp (-4068/T) s -1 . The equilibrium constant is found from the ratio of k f /k r : (K eq ( 30%) ) 2.0 × 10 2 exp (2256/T) M -1 or (3.9 ( 1.2) × 10 5 M -1 at 298 K. The reaction entropy and enthalpy are ∆S R°) 44 ( 6 J mol -1 K -1 and ∆H R°) -19 ( 2 kJ mol -1 , respectively. The corresponding reaction reduction potential is ∆E°) 0.33 ( 0.01 V, in very good agreement with that calculated from half-cell potentials. In addition, preliminary rate constants for Br 2 -• + Br 2 -• f Br 3 -+ Brand the hydrogen abstraction reaction (Br • + BrCH 2 CH 2 Br f • CBrH-CH 2 -Br + H + + Br -) are reported.

The Journal of Physical …, Jan 1, 1977

International Journal of Chemical Kinetics, Jan 1, 2001

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