Spectral and Quantum‐Chemical Investigation of the Influence of the Spatial Structure of a Polymeric Complex on the Mechanism of Catalytic Oxidation of Sulfur Dioxide with Oxygen

Abstract

Based on the calculations carried out by the ZINDO/S method, we suggest interpretation of the electronic absorption spectra of solvate complexes of cobalt with polyethyleneimine and sulfite ion. The quantum‐chemical analysis of the spectrophotometric data has shown that the change in a concentration of cobalt ions in a solution leads to conformation changes in a polymeric chain. The kinetic and quantum‐chemical investigation of the mechanism of catalytic oxidation of SO₃ ²⁻ to SO₄ ²⁻ is carried out. We suggest a spatial structure of the transient state that provides optimum conditions for the oxygenation reaction. The kinetic data indicate that the catalytic activity of cobalt ions fixed on a polymeric matrix is by three orders of magnitude higher than of their monomeric analogs. Using calculations performed by the RM3 method, we show that the oxygenation process is of exothermal nature and that there is a direct correlation between the reaction‐rate constant and the energy released in the process of oxygenation (ΔE). On substituting ammonia molecules by a polyethyleneimine fragment, ΔE increases by 39.39 kcal/mole.