Kinetics of the iodination of ethyl pyruvate

The production and decay of the ClO radical and of vibrationally excited oxygen following the isothermal flash photolysis of chlorine dioxide has been studied. From their dependence on flash energy and from the effects of added chlorine, oxygen and chlorine monoxide on the system, the following mechanism and rate constants are proposed: ClO$_{2}$ + h$\nu $ $\rightarrow $ ClO + O 2ClO $\rightarrow $ Cl$_{2}$ + O$_{2}$ $k_{1}$ = 2.7 $\times $ 10$^{7}$ lmol$^{-1}$ s$^{-1}$ O + ClO$_{2}\rightarrow $ ClO + O$_{2}^{\ast}$ $(v^{\prime \prime}\leq $ 15) $k_{3}$ = 3.0 $\times $ 10$^{10}$ lmol$^{-1}$ s$^{-1}$ O + ClO $\rightarrow $ Cl + O$_{2}^{\ast}$ $(v^{\prime \prime \}\leq $ 14) $k_{4}$ = 7.0 $\times $ 10$^{9}$ lmol$^{-1}$ s$^{-1}$ ClO (ClO$_{2}$) + O$_{2}^{\ast}(v^{\prime \prime}=n)\rightarrow $ ClO (ClO$_{2}$) + O$_{2}^{\ast}(v^{\prime \prime}<n)\ k_{10}(v^{\prime \prime}=12)=2\times 10^{8}$ lmol$^{-1}$ s$^{-1}$ Cl + O$_{2}^{\ast}(v^{\prime \prime}=n)\rightarrow $ Cl + O$_{2}^{\ast}(v^{\prime \prime}<n)$ $k_{11}(v^{\prime \prime}=12)$ = 7 $\times $ 10$^{9}$ lmol$^{-1}$ s$^{-1}$ O + O$_{2}^{\ast}(v^{\prime \prime}=n)\rightarrow $ O + O$_{2}^{\ast}(v^{\prime \prime}<n)$ $k_{12}(v^{\prime \prime}=12)$ = 2 $\times $ 10$^{10}$ lmol$^{-1}$ s$^{-1}$ O + Cl$_{2}O\rightarrow $ 2ClO $k_{6}$ = 5.2 $\times $ $10^{9}$ lmol$^{-1}$ s$^{-1}$ The rate constants $k_{10},k_{11}$ and $k_{12}$ for O$_{2}^{\ast}(v^{\prime \prime}$ = 6) and the relative values of $k_{3}$ for various vibrational levels have also been measured. Studies of the flash photolysis of mixtures of chlorine monoxide and chlorine dioxide and of chlorine and oxygen have yielded values of $k_{1}$ in agreement with that given above. The extinction coefficients of the ClO radical at 257.7, 277.2 and 292 nm were found to be 1150, 1700 and 1050 l mol$^{-1}$ cm$^{-1}$ respectively.