ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The rate of decomposition of ethyl nitrite (EN) has been studied in a static system over the temperature range of 162-218°C. The main products are formaldehyde, acetaldehyde, ethanol, and nitrous oxide. For low concentrations of EN (10-5-10-4M), but with a high total pressure of CF4 (∼0.9 atm) and small extents of reaction (2-6%), the first-order homogeneous rates of CH2O formation are a direct measure of reaction (1), since k3bk2(NO): Addition of large amounts of NO(∼0.9 atm) completely suppressed CH2O formation in agreement with the observed value for k3b.The rate of reaction (1) is given by k1 = 1016.0-41.8/θ-1. Since (E1 + RT) and ΔH±1 are identical, both may be equated with D(EtO-NO) = 42.4 ± 0.9 kcal/mol and E2 = O± 1 kcal/mol. The thermochemistry leads to the result ΔHDelta;f(EN) = -24.5 ± 1 kcal/mol. From ΔS1 and A1, k2 is calculated to be 1010.3M-1θ-1. From an independent observation that k6/k2 = 0.3 ± 0.05 independent of temperature \documentclass{article}\pagestyle{empty}\begin{document}$$ {{\rm EtO + NO}} \stackrel{6}{\longrightarrow} {{\rm AcH} + {\rm HNO}} $$\end{document} it is concluded that k6 = 109.8M-1Δ-1.The addition of NO has no effect on the AcH yields. Although the yields of AcH are affected by the surface-to-volume ratio of different reaction vessels, it is concluded that in a spherical reaction vessel, the AcH arises as the result of an essentially homogeneous elimination of HNO from EN(5): \documentclass{article}\pagestyle{empty}\begin{document}$$ {{\rm EN}} \stackrel{5}{\longrightarrow} {{\rm AcH} + {\rm HNO}} $$\end{document} and reaction (6). The rate of AcH formation is given by kobs = 1013.7-37.5/θ-1. By using isobutane (t-BuH) as a radical trap for EtO (4), \documentclass{article}\pagestyle{empty}\begin{document}$$ {{\rm EtO} + t - {\rm BuH}} \stackrel{4}{\longrightarrow} {{\rm EA} + (t - {\rm Bu})} $$\end{document} a value for k3b was determined to be 1015.0-21.6/θ s-1.From an independent observation that k2:k2:k6:k6 was 1: 0.4: 0.3: 0.18 we find k2θ = 109.9M-1→ s-1, k1θ = 1016.0-40.0/θ s-1, and k6± = 109.6M-1 · s-1.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550090405
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