Decay Mechanism of NO3• Radical in Highly Concentrated Nitrate and Nitric Acidic Solutions in the Absence and Presence of Hydrazine

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• 作者：Guillaume Garaix ; Gregory P. Horne ; Laurent Venault ; Philippe Moisy ; Simon M. Pimblott ; Jean−Louis Marignier ; Mehran Mostafavi
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：June 9, 2016
• 年：2016
• 卷：120
• 期：22
• 页码：5008-5014
• 全文大小：421K
• 年卷期：0
• ISSN：1520-5207

文摘

The decay mechanism of NO₃^• has been determined through a combination of experiment and calculation for 7 mol dm^–3 solutions of deaerated aqueous LiNO₃ and HNO₃, in the absence and presence of hydrazine (N₂H₄, N₂H₅⁺, and N₂H₆²⁺). In the absence of hydrazine, the predominant NO₃^• decay pathways are strongly dependent upon the pH of the solution. For neat, neutral pH LiNO₃ solutions (7 mol dm^–3), NO₃^• produced by the pulse is fully consumed within 160 μs by OH^• (37%), H₂O (29%), NO₂^– (17%), and NO₂ (17%). For acidic HNO₃ solutions (7 mol dm^–3), radiolytically produced NO₃^• is predominantly consumed within 1 ms by HNO₂ (15%) and NO₂ (80%). Intervening formulations exhibit the mechanistic transition from neat LiNO₃ to neat HNO₃. In highly acidic nitric acid solution, hydrazine exists mainly as N₂H₅⁺ and N₂H₆²⁺, both of which rapidly consume NO₃^• in addition to other decay mechanisms, with rate constants of 2.9 (±0.9) × 10⁷ and 1.3 (±0.3) × 10⁶ dm³ mol^–1 s^–1, respectively.