亜セレン酸 化学特性,用途語,生産方法
外観
白色の結晶
溶解性
水に易溶 (167g/100ml, 20℃), エタノールに易溶。水及びエタノールに極めて溶けやすい。
解説
亜セレン酸，化学式H2SeO3。二酸化セレンSeO2を熱湯に溶かし加熱濃縮し，冷却すると得られる，無色または白色の六方晶系の結晶。吸湿性がある。融点約70℃，比重3.00(15℃)，水に溶けて弱い酸性を呈する。酸解離指数pKa1＝2.54,pKa2＝8.02(18℃)。エチルアルコールに可溶。結晶を熱すれば水を失いSeO2となる。中程度に強い酸化剤であり，二酸化硫黄SO2，ヨウ化水素HI，硫化水素H2Sなどを酸化し，自身は容易に還元されて金属セレンになる。
効能
セレン補充薬
性質
おもな同素体として，無定形セレン，単斜晶系セレン，灰色(金属)セレンがある。無定形セレンには，融解セレンの急冷による黒色(薄層では赤色)のガラス状セレンと，亜セレン酸塩の還元による赤色の粉末セレンがある。粉末セレンは二硫化炭素に可溶で，この溶液を72℃以下で蒸発結晶化すると深紅色のα形およびβ形の単斜晶系セレンが生成する。
説明
Selenious acid is a colourless, deliquescent crystal in appearance. It decomposes on heating,
producing water and toxic fumes of selenium oxides.
It is incompatible with strong reducing agents, organic materials, and finely powdered
metals and reacts on contact with acids producing toxic gaseous hydrogen selenide.
Selenious acid is a non-combustible chemical. On fire/burning, it emits irritating or toxic
fumes (or gases).
The major use of selenious acid is in changing the colour of steel, especially the steel in
guns from silver grey to blue grey. It is also used for the chemical darkening and patination
of copper brass and bronze, producing a rich dark-brown colour that can be further
enhanced with mechanical abrasion.
化学的特性
Selenious acid is a colorless, crystalline solid.
使用
As a reagent for alkaloids; as oxidizing agent.
一般的な説明
Colorless solid, transparent, colorless crystals. Used as a reagent for alkaloids and as an oxidizing agent. Isotope is used in labeling radiopharmaceuticals.
反応プロフィール
Selenious acid decomposes when heated to toxic and volatile selenium dioxide. Serves as an oxidizing agent. Reacts exothermically with many reducing agents including hydroiodic acid, sulfurous acid, sodium hyposulfite, hydroxylamine salts, hydrazine salts, hypophosphorous acid, phosphorous acid [Merck]. Oxidizes many organic substances. Is oxidized to selenic acid by strong oxidizing agents.
危険性
Toxic by inhalation, ingestion, and skin
absorption.
健康ハザード
Selenious acid and its salts are capable of penetrating the skin and can produce acute poisonings. Causes irritations and burns of the skin. It is highly toxic orally. Inorganic selenium compounds may cause dermatitis.
火災危険
When heated to decomposition Selenious acid emits toxic fumes of selenium. Avoid heating.
安全性プロファイル
Poison by ingestion, intraperitoneal, and intravenous routes. Human mutation data reported. Used as an oxidizing agent. When heated to decomposition it emits toxic fumes of Se. See also SELENIUM COMPOUNDS
職業ばく露
Selenious acid is used as a reagent for alkaloids and as an oxidizing agent. Isotope is used in labeling radiopharmaceuticals.
輸送方法
UN3283Selenium compound, solid, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous material, Technical Name Required. UN3440 Selenium compound, liquid, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous material, Technical Name Required.
純化方法
Recrystallise the acid from water. On heating it loses water and SeO2 sublimes. [Waitkins & Clark Chem Rev 36 235 1945.]
不和合性
A strong oxidizer. Reacts exothermically with many reducing agents including hydroiodic acid, sulfurous acid, sodium hyposulfite, hydroxylamine salts, hydrazine salts, hypophosphorous acid, phosphorous acid. Incompatible combustibles, organic material, oxidizable materials, strong acids, strong bases. Contact with acids produce toxic and gaseous hydrogen selenide. Attacks metals.
廃棄物の処理
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal.
亜セレン酸 上流と下流の製品情報
原材料
準備製品