二硝酸鉛(II) 化学特性,用途語,生産方法
外観
白色, 結晶〜結晶性粉末
溶解性
水に溶け易い (20℃で水100mlに56.5g溶ける)。水に溶けやすく、エタノール(99.5)にほとんど溶けない。
解説
硝酸鉛一般に硝酸鉛(II)，化学式Pb(NO3)2を指す。PbIV(NO3)4は不安定で単離されていない。鉛，酸化鉛(II)，炭酸水酸化鉛(II)(鉛白)を硝酸に溶解し，溶液を蒸発して乾固すると無色の立方晶系または単斜晶系に属する結晶として得られる。比重4.53(20℃)。加熱すると470℃で分解して酸化鉛(II)になる。水には比較的よく溶け(100gの水に20℃で56.5g，100℃で135g)，水溶液は弱酸性を示す。水に溶ける。水酸化アルカリにより水酸化鉛(Ⅱ)を沈殿するが、過剰に溶けて亜鉛(あなまり)酸塩となる。顔料の製造原料、マッチ、爆薬、防腐剤、収斂(しゅうれん)剤、染色、試薬などの用途がある。
用途
鉛化合物原料、マッチ?爆薬?光学ガラス原料、試薬。
化学的特性
The lead nitrate appears as a white cubic crystal or monoclinic crystalline powder. It is soluble in water and liquid ammonia, being slightly soluble in the ethanol, being insoluble in concentrated nitric acid (produce protective film); it can react with concentrated hydrochloric acid or concentrated alkali chloride solution to form complex chlorinated lead acid or chlorinated lead acid salt; it has strong oxidizing property and may cause the risk of inducing combustion and explosion if mixed with organic matter, reducing agent and combustible substance such as sulfur and phosphorus or even subject to slightly friction. The dry lead nitrate can be subject to decomposition at around 205 ~223 while a temperature of 100 is enough to trigger the decomposition of wet lead nitrate. Its decomposition can emit toxic nitric oxide gas.
物理的性質
Colorless cubic or monoclinic crystals; refractive index 1.782; density 4.53 g/cm
3 at 20°C; decomposes at 470°C; soluble in cold water; very soluble in boiling water 127 g/100 mL at 100°C; also soluble in caustic soda, caustic potash and ammonia solution, and moderately soluble in alcohol.
使用
Lead(II) nitrate is employed in industrial applications such as heat stabilization in nylon and polyesters and coatings of photothermographic paper. It is utilized to improve the leaching process in the gold cyanidation. It finds applications as a lead paint as well as a source of dinitrogen tetroxide. As an oxidant, it is used in the oxidation of benzylic halides to aldehydes in organic synthesis. It is also used in the preparation of dithiocarbamates from isothiocyanates. It acts as a scavenger of bromide in nucleophilic substitution reactions.
製造方法
Lead nitrate is prepared by dissolving lead metal, lead monoxide or lead carbonate in excess dilute nitric acid followed by evaporation of and/or cooling the solution for crystallization.
一般的な説明
Lead dinitrate is a white crystalline solid. The material is soluble in water. Lead dinitrate is noncombustible but Lead dinitrate will accelerate the burning of combustible materials. If large quantities of the material are involved in the fire an explosion may result. Prolonged exposure of the material to fire or heat may result in an explosion. Toxic oxides of nitrogen are produced in fires involving Lead dinitrate.
空気と水の反応
Water soluble.
反応プロフィール
Mixtures of metal/nonmetal nitrates with alkyl esters may explode because of the formation of alkyl nitrates; mixtures of nitrate with phosphorus, tin (II) chloride or other reducing agents may react explosively [Bretherick 1979. p. 108-109]. An explosion of guanidine nitrate demolished an autoclave built to withstand 50 atmospheres, in which Lead dinitrate was being made from ammonium thiocyanate and Lead dinitrate [C. Angew. Chem. 49:23. 1936].
危険性
The toxic effects are greater than other lead salts because lead nitrate is more soluble. Moderately toxic by ingestion and other routes of exposure. The compound also is an irritant to eye, skin, and mucous membranes.
健康ハザード
Early symptoms of lead intoxicatin via inhalation or ingestion are most commonly gastrointestinal disorders, colic, constipation, etc.; weakness, which may go on to paralysis, chiefly of the extensor muscles of the wrists and less often the ankles, is noticeable in the most serious cases. Ingestion of a large amount causes local irritation of the alimentary tract; pain, leg cramps, muscle weakness, paresthesias, depression, coma, and death may follow in 1 or 2 days. Contact with eyes causes irritation.
工業用途
This is a white to colorless fine crystalline compound, extremely soluble in water (34%
at 20 °C). Commercial production is based on dissolution of lead metal or lead compounds
in nitric acid (36–40% solution). Lead nitrate is considered to be an activator in
mineral processing. Although lead may activate sphalerite, similar to CuSO
4, the use of
Pb(NO
3)
2 is limited to the activation of stibnite during beneficiation of antimony ores.
Lead nitrate is the most widely used chemical in cyanidation of precious metals as an
accelerator.
純化方法
Precipitate it twice from a hot (60o) concentrated aqueous solution by adding HNO3. The precipitate is sucked dry on a sintered-glass funnel, then transferred to a crystallising dish which is covered by a clock glass and left in an electric oven at 110o for several hours [Beck et al. Trans Faraday Soc 55 331 1959]. After two recrystallisations of ACS grade, no metals above 0.001ppm were detected.
二硝酸鉛(II) 上流と下流の製品情報
原材料
準備製品
