ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A laser-flash photolysis/UV absorption technique has been used to study the temperature dependence (from T = 300 - 470 K) of the self-reaction kinetics of representative primary secondary and tertiary β-hydroxyperoxy radicals \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{lclr} 2\,\rm{HOCH}_2\rm{CH}_2\rm{O}_2 & \longrightarrow & 2\,\rm{HOCH}_2\rm{CH}_2\rm{O}\,+\,\rm{O}_2 & (1\rm{a})\\ & \longrightarrow & \rm{HOCH}_2\rm{CH}_2\rm{OH}\,+\rm{HOCH}_2\rm{CH}_2\rm{O}\,+\,\rm{O}_2 & (1\rm{b})\\ 2\,\rm{HOCH}(\rm{CH}_3)\rm{CH}(\rm{CH}_3)\rm{O}_2 & \longrightarrow & 2\,\rm{HOCH}(\rm{CH}_3)\rm{CH}(\rm{CH}_3)\rm{O}\,+\,\rm{O}_2 & (2\rm{a})\\ & \longrightarrow & \rm{HOCH}(\rm{CH}_3)\rm{CH}(\rm{CH}_3)\rm{OH} & \\ & &+\rm{HOCH}(\rm{CH}_3)\rm{CH}(\rm{CH}_3)\rm{O}+\rm{O}_2 & (2\rm{b})\\ 2\,\rm{HOC}(\rm{CH}_3)_2\rm{C}(\rm{CH}_3)_2\rm{O}_2 & \longrightarrow & 2\,\rm{HOC}(\rm{CH}_3)_2 \rm{C}(\rm{CH}_3)_2\rm{O}\,+\,\rm{O}_2 & (3)\\ \end{array} $$\end{document} The following Arrhenius expressions were derived for the rate coefficients of reactions (1)-(3) (in cm3 molecule -1s-1) and for the product branching ratios of reactions (1) and (2) as a function of temperature (all errors 1σ) \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{l}k_1=(6.9_{+2.1}^{-1.5})\times 10 ^{-14}\,\exp[(1040\pm 100)/\rm{T}]\\ \beta_1=(3100_{+3700}^{-1700})\,\exp[(-2400\pm 280)/\rm{T}] (\hbox{ where } \beta_1=k_{1a}/k{1\rm{b}})\\ k_2=(7.7_{+12.8}^{-4.8})\times 10 ^{-15}\,\exp[(1330\pm 350)/\rm{T}]\\ \beta_2=(4.0_{+0.2}^{-0.1})\times 10 ^{4}\,\exp[(-3600\pm 100)/\rm{T}]\\ k_3=(4.7_{+6.5}^{-2.7})\times 10 ^{-13}\,\exp[(-1420\pm 320)/\rm{T}]\\ \end{array} $$\end{document} The calculated rate coefficients for reactions (1)-(3) at 298 K are therefore (in 10-13 cm3molecule -1s -1 23 ± 2, 6.7 ± 1.3, and 0.040 ± 0.012, respectively which compare well with the values measured elsewhere at this temperature using a similar technique. The product branching ratios and the Arrhenius parameters are compared with those for other substituted and unsubstituted peroxy radical self reactions. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 323-331, 1997
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
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