四酸化二窒素 化学特性,用途語,生産方法
解説
N2O4(92.01)．四酸化二窒素は，二酸化窒素を冷却すると無色の固体として得られる．融点－9.3 ℃．液体は淡黄色であるが，この色は二酸化窒素の存在による．沸点21.2 ℃ では約1％ のNO2を含む．気体は高温になるほどNO2が増し，100 ℃ で約90％ NO2となる．アルカリ金属と反応して硝酸塩と一酸化窒素を生じる．液体はNO＋とNO3－に分解しやすい．森北出版「化学辞典（第2版）
用途
酸化反応時の触媒、アクリル誘導体蒸留時の重合防止剤、ロケット推進薬原料
用途
四酸化二窒素は，気体状態では二酸化窒素と平衡混合物になり、淡黄色を呈する。ロケット燃料の酸化剤などに用いられる。液体N2O4は無水硝酸塩をつくるときの溶媒，宇宙機ヒドラジン燃料の酸化剤などに用いられる．大気汚染物質(NOx)の一種である．
説明
Nitrogen tetraoxide is primarily known for its use as a rocket
propellant and became an oxidizer of choice by the late 1950s.
Nitrogen tetraoxide has been used as a propellant for missiles
as well as for spacecraft beginning with its use in Titan rockets
in the late 1950s.
化学的特性
col liquid [CRC10]
物理的性質
Colorless liquid or gas; exists in equilibrium with NO
2; density 1.45 g/mL at 20°C; boils at 21.25°C; freezes at -9.35°C to a colorless diamagnetic solid; critical temperature 157.85°C; critical pressure 99.64 atm; critical volume 167 cm
3/mol; reacts with water.
使用
Nitrogen tetroxide is a solvent and a powerful and selective oxidizing agent. It’s adducts with organic solvents are used to synthesize nitrates of noble metals.
定義
A colorless gas that becomes a pale yellow
liquid below 21°C and solidifies below
–11°C. On heating, the gas dissociates to
nitrogen dioxide molecules:
N
2O
4(g) = 2NO
2(g)
This dissociation is complete at 140°C.
Liquid dinitrogen tetroxide has good solvent
properties and is used as a nitrating
agent.
製造方法
Nitrogen tetroxide always is formed along with nitrogen dioxide during preparation of the dioxide (See Nitrogen Dioxide.) Mixed oxides are produced by oxidation of nitric oxide (NO) in air, heating metal nitrates, or by metals reacting with nitric acids or nitrates.
一般的な説明
Red-brown liquid with a sharp, unpleasant chemical odor. Low-boiling (boiling point 21.15°C) and held as a liquid by compression. Density 1.448 g / cm3. Consists of an equilibrium mixture of brown NO2 (nitrogen dioxide) and colorless N2O4 (diNITROGEN DIOXIDE). Evolves poisonous brown vapors. Cylinders and ton containers may not be equipped with a safety relief device. Prolonged exposure of the containers to fire or heat may result in their violent rupturing and rocketing.
空気と水の反応
Reacts with water to form nitric acid and nitric oxide.
危険性
See Nitrogen Dioxide, Hazard.
健康ハザード
Very concentrated fumes produce coughing, choking, headache, nausea, pain in chest and abdomen; otherwise, few symtoms appear at time of exposure. After symptom-free period of 5-72 hours, pulmonary edema gradually develops, causing fatigue, restlessness, coughing, difficulty in breathing, frothy expectoration, mental confusion, lethargy, bluish skin, and weak, rapid pulse. Since NOX interferes with gas exchange in lungs, unconscious- ness and death by asphyxiation can result, usually within a few hours after onset of pulmonary edema.
安全性プロファイル
A poison. Moderately
toxic by inhalation. When heated to
decomposition it emits toxic fumes of NOx.
See also NITROGEN MONOXIDE.
環境運命予測
Nitrogen tetroxide is released into the atmosphere where it can
undergo reactions, leading to air pollution.
純化方法
Purify it by oxidation at 0o in a stream of oxygen until the blue colour changes to red-brown. Alternatively distil it from P2O5, then solidify it by cooling in a deep-freeze (at –78o, giving nearly colourless crystals). Oxygen can be removed by alternate freezing and melting. TOXIC VAPOUR. [Schenk in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I pp 488-489 1963.]
四酸化二窒素 上流と下流の製品情報
原材料
準備製品