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The oxidation of HI at low temperatures and the heat of formation of HO 2
Author(s) -
Shum Lilian G. S.,
Benson Sidney W.
Publication year - 1983
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550150403
Subject(s) - chemistry , iodide , activation energy , kinetics , reaction rate constant , hydrogen , work (physics) , thermodynamics , radical , oxygen , standard enthalpy of formation , analytical chemistry (journal) , inorganic chemistry , organic chemistry , physics , quantum mechanics
The kinetics of the oxidation of hydrogen iodide (HI + O 2 ) at low temperature (414–499 K) in the gas phase by the method of iodination kinetics is complicated by a heterogeneous reaction between hydrogen iodide and oxygen. Present work leads to an upper limit for the bimolecular rate constant k 1 for the first and rate‐determining stepThese data are combined with an estimated A factor A 1 = 10 9.3±0.2 L/mol·s (assuming a tight linear I···H···O— transition state), to calculate the lower limit of the activation energy for the forward reaction E 1 . This leads to a minimum value for the heat of formation of the HO 2 radical, Δ H f 298 ° (HO 2 ) < 3.0 kcal/mol.