二クロム酸ナトリウム 化学特性,用途語,生産方法
性質
Na2Cr2O7(261.97)．IUPAC体系名はヘプタオキシド二クロム酸ナトリウム．工業的には，クロム鉄鉱(chromite)FeCr2O4，石灰，Na2CO3の粉末混合物をばい焼後，水で抽出し，酸を加えて濃縮し，二水和物の結晶を析出させる．そのほか，CrO3をNa2CO3で中和するか，Na2CrO4水溶液を酸性にした後，濃縮析出させる製法もある．二水和物は赤橙色の単斜晶系結晶．約85 ℃ で無水塩になる．室温で安定な無水塩はβ相で，三斜晶系のイオン結晶．2個の四面体型のCrO4が1個のO原子を共有して結合したCr2O72－をもつ．Cr-O1.61 Å(末端)，1.78 Å(架橋)．∠Cr-O-Cr131°．240 ℃ 以上でα相(三斜晶系)にかわる．融点356.7 ℃．400 ℃ 以上で分解して O2 を放出する．強力な酸化剤．水に易溶(20 ℃ で273 g/100 g)．水溶液は弱酸性(1％ 液の pH 約4.0)である．森北出版「化学辞典（第2版）
用途
二クロム酸ナトリウムは，各種の二クロム酸塩，クロム酸塩，クロム化合物の原料，皮なめし，媒染剤，有機合成などでの酸化剤，さび止め処理，木材の防腐，油脂の漂白処理などに利用される．六価クロム化合物として化学物質排出把握管理促進法・特定1種指定．毒劇法では重クロム酸塩として劇物指定．労働安全衛生法・名称等を通知すべき危険物及び有害物指定．
化学的特性
Sodium chromate, including the hexahydrate, is yellow crystalline solids that can also be used in solution. Disodium dichromate (10588-01-9):
使用
Sodium dichromate is red solid, soluble, powerful oxidizing agent, and consequently a fire hazard with dry carbonaceous materials. Formed by acidifying sodium chromate solution, and then evaporating. Used (1) in matches and pyrotechnics, (2) in leather tanning and in the textile industry, (3) as a source of chromate, cheaper than potassium dichromate.
一般的な説明
A red or red-orange crystalline solid. May be strongly irritating to skin, eyes and mucous membranes. Used as a corrosion inhibitor, and in the manufacture of other chemicals.
空気と水の反応
Deliquescent. Soluble in water.
反応プロフィール
SODIUM DICHROMATE is a strong oxidizing agent. Incompatible with strong acids. . Contact with combustible materials may lead to fires. Toxic chromium oxide fumes may form in fire [USCG, 1999]. The well known "chromic acid mixture" of dichromate and sulfuric acid with organic residue led to violent exothermic reaction. This mixture in combination with acetone residue also led to violent reaction. The combination of the dichromate and sulfuric acid with alcohols, ethanol and 2-propanol, led to violent exothermic reaction. Because of the occurrence of many incidents involving the dichromate-sulfuric acid mix with oxidizable organic materials, SODIUM DICHROMATE is probably best to avoid such interactions. The combination of the dichromate with hydrazine is explosive (one may expect the reaction of the dichromate to be vigorous with amines in general), [Mellor, 1943, Vol. 11, 234]. The addition of the dehydrated dichromate salt to acetic anhydride led to an exothermic reaction which eventually exploded. An induction period proceeded the explosion event [Bretherick, 5th Ed., 1995]. Boron, silicon, and dichromates form pyrotechnic mixtures. A mixture of acetic acid, 2-methyl-2-pentenal and the dichromate led to a runaway reaction and eruption of the reactor contents, [J. Haz. Mat., 1987, 233-239].
健康ハザード
Inhalation of dust or mist causes respiratory irritation sometimes resembling asthma; nasal septal perforation may occur. Ingestion causes vomiting, diarrhea, and (rarely) stomach and kidney complications. Contact with eyes or skin produces local irritation; repeated skin exposure causes dermatitis.
火災危険
Behavior in Fire: Decomposes to produce oxygen when heated. May ignite other combustibles upon contact.
安全性プロファイル
Confirmed carcinogen with experimental tumorigenic data. Poison by ingestion, sktn contact, intravenous, intraperitoneal, and subcutaneous routes. Human systemic effects by ingestion: cough, nausea or vomiting, and sweating. Human mutation data reported. A caustic and irritant. A powerful oxidizer. Potentially explosive reaction with acetic anhydride, ethanol + sulfuric acid + heat, hydrazine. Violent reaction or ignition with boron + shcon (pyrotechnic), organic residues + sulfuric acid, 2-propanol + sulfuric acid, sulfuric acid + trinitrotoluene. Incompatible with hydroxylamine. When heated to decomposition it emits toxic fumes of Na2O. See also CHROMIUM COMPOUNDS.
職業ばく露
Used to make dyes, inks, pigments, and other chromates; in leather tanning, a corrosion inhibitor in circulating water systems; metal treatment; a drilling mud additive; chemical intermediate for chromium catalysts; colorimetry, oxidizing agent; bleaching agent; an algicide, fungicide, insecticide; in wood preservation.
輸送方法
UN3087 Oxidizing solid, toxic, n.o.s., Hazard Class: 5.1; Labels: 5.1-Oxidizer, 6.1-Poisonous materials, Technical Name Required. UN3085 Oxidizing solid, corrosive, n.o.s., Hazard Class: 5.1; Labels: 5.1-Oxidizer, 8-Corrosive material, Technical Name Required.
不和合性
Aqueous solution in a base. A strong oxidizer. Violent reaction with reducing agents; combustibles, strong acids; organic materials.
二クロム酸ナトリウム 上流と下流の製品情報
原材料
準備製品