在极地平流层云层中酸三水合物 (NAT)
C Voigt1, J Schreiner, A Kohlmann
1Max-Planck-Institut für Kernphysik, Division of Atmospheric Physics, Post Office Box 103 980, D-69029 Heidelberg, Germany.
概括
极地平流层云中含有酸三水合物 (NAT) 颗粒,存在于冰形成温度以上. 这些NAT粒子有助于极地地区的臭氧消耗.
科学领域:
- 大气化学 大气化学
- 极地气象学 极地气象学
背景情况:
- 极地平流层云 (PSCs) 在极地臭氧消耗中发挥着关键作用.
- 了解PSC的组成对于大气建模至关重要.
研究的目的:
- 调查公共服务中心的组成.
- 确认PSC中存在酸三水合物 (NAT) 颗粒.
主要方法:
- 气球载仪器从瑞典基鲁纳发射.
- 在20-24公里高度的云层现场测量.
主要成果:
- 在海拔20至24公里之间观察到PSC层.
- 颗粒分析显示了大量的酸三水合物 (NAT) 颗粒.
- 在高于冰形成点的温度下存在NAT粒子.
结论:
- 固体NAT粒子存在于PSC中,温度高于形成冰的温度.
- 存在NAT粒子有助于激活,导致臭氧破坏.
- 这一发现特别适用于极地冬季早期和晚期臭氧消耗.
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Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
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Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
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