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La vida atmosférica de CHF2Br, un sustituto propuesto para los halones
Science (New York, N.Y.)
|May 3, 1991
Resumen
Se midió la velocidad de reacción del radical hidroxilo (OH) con CHF ((2) Br, revelando una vida atmosférica más corta de aproximadamente 7 años para CHF ((2) Br en comparación con compuestos similares.
Área de la Ciencia:
- Química de la atmósfera química de la atmósfera
- La cinética química es la cinética química.
Sus antecedentes:
- Comprender el destino atmosférico de los halocarbonos es crucial para evaluar su impacto ambiental.
- CHF ((2) Br es un halocarbono con potencial relevancia para el agotamiento del ozono.
Objetivo del estudio:
- Para determinar los coeficientes de velocidad para la reacción de OH con CHF(2) Br.
- Para medir las secciones transversales de absorción ultravioleta de CHF ((2) Br.
- Para calcular el tiempo de vida atmosférico y el potencial de agotamiento del ozono de CHF ((2) Br.Br.
Principales métodos:
- Se emplearon técnicas de fotólisis pulsada y de flujo de descarga para medir los coeficientes de velocidad de reacción a temperaturas que oscilaban entre 233 y 432 K.
- Se midieron las secciones transversales de absorción ultravioleta a 296 K.
- Se utilizó un modelo atmosférico unidimensional.
Principales resultados:
- El coeficiente de velocidad k(1) para la reacción OH + CHF(2) Br fue determinado como (7.4 +/- 1.6) x 10(-13) exp[-(1300 +/- 100) /T] cm(3) / molécula/s.
- Se calculó que la vida útil atmosférica del CHF ((2) Br era de aproximadamente 7 años.
- Esta vida útil es significativamente más corta que las de CF(3) Br y CF(2) Cl.Br.
Conclusiones:
- CHF ((2) Br tiene una vida útil atmosférica más corta en comparación con CF ((3) Br y CF ((2) ClBr.
- Los parámetros cinéticos determinados y la vida útil sugieren un menor potencial de agotamiento del ozono para CHF ((2) Br en relación con estos compuestos.
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