| 化学名: | カリウム | | 英語化学名: | Potassium | | 别名: | potassium,metalalloys;CHLORO POTASSIUM;CONDUCTANCE STANDARD 300 000 UMHO;CONDUCTANCE STANDARD SOLUTION B;CONDUCTANCE STANDARD SOLUTION C;CONDUCTIVITY CALIBRATION STANDARD 10;CONDUCTIVITY CALIBRATION STANDARD 100;CONDUCTIVITY CALIBRATION STANDARD 1,000 | | CAS番号: | 7440-09-7 | | 分子式: | K | | 分子量: | 39.1 | | EINECS: | 231-119-8 | | カテゴリ情報: | metal or element;Inorganics;INORGANIC & ORGANIC CHEMICALS | | Mol File: | 7440-09-7.mol |  |
| 融点 | 64 °C (lit.) | | 沸点 | 760 °C (lit.) | | 比重(密度) | 0.86 g/mL at 25 °C (lit.) | | 蒸気圧 | 0.09 mm Hg ( 260 °C) | | 屈折率 | n20/D 1.334 | | 貯蔵温度 | 2-8°C | | 溶解性 | H2O: soluble | | 外見 | rod | | 比重 | 0.86 | | 色 | Silver/gray | | 臭い (Odor) | Odorless | | PH | 5.0 (H2O, 20°C) | | 電気抵抗率 (resistivity) | 6.1 μΩ-cm, 20°C | | 水溶解度 | reacts | | Sensitive | Air & Moisture Sensitive | | 暴露限界値 | ACGIH: TWA 2 ppm; STEL 4 ppm
OSHA: TWA 2 ppm(5 mg/m3)
NIOSH: IDLH 25 ppm; TWA 2 ppm(5 mg/m3); STEL 4 ppm(10 mg/m3) | | Dielectric constant | 5（0.0℃） | | 安定性： | Stable. Moisture and air-sensitive. Spontaneously combustible through the generation and ignition of hydrogen. Reacts violently with water and acids, alcohols, carbon monoxide. Store under oil. | | CAS データベース | 7440-09-7(CAS DataBase Reference) | | NISTの化学物質情報 | Potassium(7440-09-7) | | EPAの化学物質情報 | Potassium (7440-09-7) |
| 主な危険性 | F,C,Xi,T | | Rフレーズ | 14/15-34-36/38-23/24/25 | | Sフレーズ | 8-43-45-5B-5*-36/37/39-26-5-27 | | RIDADR | UN 2257 4.3/PG 1 | | WGK Germany | 2 | | RTECS 番号 | TS8050000 | | F | 8 | | 自然発火温度 | 25 °C or below in air or oxygen | | TSCA | Yes | | HSコード | 2827 39 85 | | 国連危険物分類 | 4.3 | | 容器等級 | I | | 有毒物質データの | 7440-09-7(Hazardous Substances Data) | | 毒性 | Ignites in air and reacts explosively with water; highly corrosive to the skin and eyes.
Potassium reacts with the moisture on skin and other tissues to form highly corrosive
potassium hydroxide. Contact of metallic potassium with the skin, eyes, or mucous
membranes causes severe burns; thermal burns may also occur due to ignition of the
metal and liberated hydrogen. |
| 歴史 | 植物体内にイオンとして存在しているので、これを焼いた灰の中には多量に含まれる。木灰ashを水で浸出した液（アルカリ液）が洗濯に有効であることは『旧約聖書』の時代から知られていた。この液を鉄製のるつぼpotで煮沸濃縮して得られる固形物はpotashとよばれ、ガラスやせっけんの製造に用いられた。これは不純な炭酸カリウムである。このpotashということばは、のちには他のカリウム塩やカ性カリ、すなわち水酸化カリウムにも用いられるようになった。カリウムの化合物はナトリウムの化合物と類似していて区別が明瞭(めいりょう)でなかったが、1761年ドイツのマルクグラーフは炎色反応によって両者を区別することに成功した。すなわち、カリウムは淡紫色を呈するのに対し、ナトリウムは黄色を呈する。 カリウムの金属単体を単離することに初めて成功したのはイギリスのデービーである（1807）。彼は、高温で融解した水酸化カリウムを電解したところ、負極で明るい光と炎が生ずるのを観察した。電極において生成し、空気中で燃焼して炎と光を発するこの金属を新元素と認め、potash（この場合は水酸化カリウム）から得たことにちなみポタシウムpotassiumと命名した。カリウムというのはドイツ語名で、アラビア語のkaljan（植物の灰）またはヘブライ語のkal（軽い）に由来するといわれる。［鳥居泰男］ | | 存在 | カリウムは他のアルカリ金属元素と同様にきわめて反応性に富んでいるので、自然界においてはつねに1価の陽イオンとして化合物の形で存在しており、単体としては産出しない。地殻中に比較的豊富に存在しており、アルカリ金属としてはナトリウムに次ぐ。不溶性アルミノケイ酸塩、たとえばカリ長石KAlSi3O8、カリ雲母(うんも)KH2Al3Si3O2のような形で岩石成分として分布している。岩石が風化すると、カリウムイオンはナトリウムイオンなどとともに遊離してくるが、ナトリウムイオンに比べ土壌中のコロイド物質に吸着されやすいので、雨水によっても比較的流出せずに残り、植物に吸収される。したがってカリウムは地殻中にはナトリウムとほぼ同量含まれているのに、海水中の存在量は30分の1ぐらいである。まれに地中から水溶性の塩化物、硫酸塩などの塩類として比較的純粋な形でみいだされる。これらは、かつて地球の大部分を覆っていた古代の海が蒸発濃縮された結果沈積したもので、多くは地下深い所に岩塩層と並んで鉱床をなしている。その最大のものはカナダのサスカチェワンのシルビン（カリ岩塩）の鉱床で、地下1キロメートルにあり、塩化カリウムの推定埋蔵量100億トンといわれ、3億年以上前に生成したものと考えられている。また、ドイツのシュタッスフルトの岩塩鉱床からカーナル石KCl・MgCl2・6H2Oが採掘されていることも有名である。 カリウムはまた動植物の細胞内液にイオンとして存在し、グリコーゲンとよばれる多糖類やタンパク質の合成に関係しており、神経の情報伝達にも重要な役割をもっている。 | | 性質 | カリウムは、軟らかい金属です。比重は0.86であり、水よりも軽く、リチウムの次に比重の軽い金属です。融点は63.7°Cで、沸点は774°Cであり、炎色反応は淡紫色を呈します。
電気陰性度が小さいルビジウムやセシウムより反応性が低く、電気陰性度が大きいリチウムやナトリウムより反応性が高いです。空気によりすぐに酸化されて灰色に変色し、水やハロゲン元素とも激しく反応します。
そのため、金属カリウムは鉱油やケロシンなどの炭化水素中やアルゴンで、満たされたガラスアンプル中で保管する必要があります。
アルコールとの反応ではアルコキシドが生成し、高温では水素と反応して水素化カリウムを得ることが可能です。水や液体アンモニアには、非常によく溶けます。
| | 解説 | K．原子番号19の元素．電子配置1s22s22p63s23p64s1の周期表1族元素．原子量39.10．2種類の安定同位体(39K，41K)がある．放射性同位体は7種類の存在が知られている．1807年H. Davy(デイビー)により水酸化カリウムの融解電解で遊離された．古くから植物の灰ashを鍋potで煮て得られる炭酸カリウムはpotashとして知られており，Davyはこれをもとにpotassiumと命名した．中世には，炭酸カリウムと天然ソーダ・炭酸ナトリウムが区別されておらず，欧州ではnatron，アラブ圏ではalkaliとまとめてよばれていたが，M.H. Klaprothが両者の違いを認めて，1797年に前者をkali，後者をnatronとよぶことを提案した．今日でもドイツ語圏では元素名はKaliumで，日本語の元素名はドイツ語名を採用している．天然には遊離状態で存在せず，おもにケイ酸塩として地殻中に広く分布する．地殻中の存在度9100 ppm．植物の灰に多く含まれる．ドイツやフランスの鉱床から塩化物，硫酸塩などの複塩として多量に産出する．また，海水中には塩化カリウムとして0.38 g dm－3 含まれている．カリウムの水酸化物，ハロゲン化物の融解電解で得られ，真空蒸留により精製する．銀白色の軟らかい金属．体心立方格子構造．格子定数a ＝ 0.533 nm(20 ℃)．融点63.65 ℃，沸点774 ℃．密度0.86 g cm－3(20 ℃)．融解熱2.4 kJ mol－1，蒸発熱77.4 kJ mol－1．イオン化電位4.318 eV．炎色反応は淡紫色．電気的陽性の強い元素で，酸化数1の化合物をつくりやすい．表面は空気中でただちに酸化されて光沢を失う．発火することもある．鉱油中に保存する．空気中で熱すると燃えて超酸化カリウムKO2を生じる．ハロゲン族，酸素族，硫黄族の元素と作用し，また水素気流中で熱すると水素化カリウムとなる．水とはげしく反応して水素を発生し，生じた水素は反応熱のため発火する．ほかの金属の塩を還元してその金属を遊離する．有機物に対し強い還元作用を示す．液体アンモニア，エチレンジアミン，アニリンなどに溶け，水銀とはアマルガムをつくり，多くの金属に合金をつくって溶ける．カリウム化合物の原料，有機合成の還元剤，縮合剤に用いられる．ナトリウム-カリウム合金は原子炉の冷却剤として用いられる．[CAS 7440-09-7]
森北出版「化学辞典（第2版） | | 用途 | 還元剤、無機および有機化合物の合成、原子炉冷却材、触媒、分析用試薬、有機過酸化物の製造 | | 用途 | 金属カリウムは多くの点でナトリウムと類似しているが、製造上の困難のためにナトリウムよりはるかに高価である。したがってナトリウムに比べ工業材料としての利用範囲（還元剤、縮合剤、火薬原料）はあまり広くはない。しかし、一方ではカリウム特有の利用価値が認められ、その面での需要が広がっている。その一つはナトリウムとの合金であって、ナトリウムに近い比熱や熱伝導性をもちながら、室温を含む広い温度範囲で液状をとるものがつくられている。これは原子炉の冷却剤や高温温度計などに使用されている。また、超酸化物として酸素マスクに多量使用されている。 | | 構造 | カリウムの元素記号はKで、原子量は39.10です。銀白色の金属であり、常温常圧では体心立方構造を取っています。
電子配置は[Ar] 4s1で、1個の電子を放出するとアルゴンと同じ安定な希ガス型の電子配置になります。そして、第1イオン化エネルギーは418.8kJ/molと低いため、電子を1個失って、陽イオン (K+) になりやすいです。電子を2個失うと希ガス型の電子配置が崩れるので、第2イオン化エネルギーは非常に高く、3052kJ/molです。その一方で、アルカリドイオンのK−も知られています。
カリウムには、24種の同位体が知られています。最も多いのは39Kです。40Kや41Kも天然に生成します。39Kと41Kは安定同位体ですが、40Kは半減期が1.250×109年と長い放射性同位体です。
| | 製法 | 金属カリウムは、一般のアルカリ金属と同様に、塩化物や水酸化物の融解電解によって製造することもできる。しかし、安全性や経済性の点から、融解塩化カリウムを850℃でナトリウム蒸気で還元する方法が現在工業的には行われている。 KCl＋Na―→NaCl＋K↑ この場合、カリウム蒸気を凝縮させて得た生成物は約1％のナトリウムを主要不純物として含んでいる。分別蒸留によって99.99％の純度にまで精製される。 | | ソース | 1. 自然界に存在するカリウム
単体のカリウムは、自然では産出されません。ただし、多種多様な化合物の形で、地殻の約2.6 %をカリウムが占めており、地殻で7番目に存在量が多い元素です。
工業原料のためのカリウム資源は、ほとんど塩化カリウムとして採取されます。
2. カリウムの生産
純粋な金属カリウムは、水酸化カリウムの電気分解によって得られます。カリウムを多く含むカーナライト、ラングバイナイト、ポリハライト、カリ岩塩のような鉱石を使用して、カリウム塩類の抽出も可能です。カリウム塩類は、マグネシウムやナトリウムの化合物から分離されます。
海も主要なカリウム源の1つですが、ナトリウムと比較して、カリウムの含有量は非常に低いです。カリウムが土壌に吸着されて、植物が吸収することが理由として挙げられます。 | | 効能 | カリウム補充薬 | | 説明 | Potassium has atomic number 19 and the chemical symbol K, which is derived from its Latin name kalium . Potassium was first isolated from potash, which is potassium carbonate (K2CO3). Potassium occurs in nature only in the form of its ion (K+) either dissolved in the ocean or coordinated in minerals because elemental potassium reacts violently with water . Potassium ions are essential for the human body and are also present in plants. The major use of K+ can be found in fertilisers, which contains a variety of potassium salts such as potassium chloride (KCl), potassium sulfate (K2SO4) and potassium nitrate (KNO3). | | 化学的特性 | Potassium is a soft silvery metal, tarnishing upon exposure to air. | | 物理的性質 | Elemental potassium is a soft, butter-like silvery metal whose cut surface oxidizes in dryair to form a dark gray potassium superoxide (KO2) coating. KO2 is an unusual compound,in that it reacts with both water and carbon dioxide to produce oxygen gas. It appears morelike a hard wax than a metal. Its density (specific gravity) is 0.862 g/cm3, its melting point is63.25°C, and its boiling point is 760°C. It has an oxidation state of +1 and reacts explosivelywith room temperature air or water to form potassium hydroxide as follows: 2K + 2 H2O→? 2KOH + H2. This is an endothermic reaction, which means the heat generated is greatenough to ignite the liberated hydrogen gas. Potassium metal must be stored in a non-oxygen,non-aqueous environment such as kerosene or naphtha. | | 同位体 | A total of 18 isotopes of potassium have been discovered so far. Just two ofthem are stable: K-39 makes up 93.2581% of potassium found in the Earth’s crust, andK-41 makes up 6.7301% of the remainder of potassium found on Earth. All the other16 potassium isotopes are unstable and radioactive with relatively short half-lives, and asthey decay, they produce beta particles. The exception is K-40, which has a half-life of1.25×109 years. | | 名前の由来 | Its symbol “K” is derived from the Latin word for alkali, kalium, but it is
commonly called “potash” in English. | | 天然物の起源 | Potassium is the eighth most abundant element in the Earth’s crust, which contains about2.6% potassium, but not in natural elemental form. Potassium is slightly less abundant thansodium. It is found in almost all solids on Earth, in soil, and in seawater, which contains 380ppm of potassium in solution. Some of the potassium ores are sylvite, carnallite, and polyhalite. Ore deposits are found in New Mexico, California, Salt Lake in Utah, Germany, Russia,and Israel. Potassium metal is produced commercially by two processes. One is thermochemical distillation, which uses hot vapors of gaseous NaCl (sodium chloride) and KCl (potassiumchloride); the potassium is cooled and drained off as molten potassium, and the sodium chloride is discharged as a slag. The other procedure is an electrolytic process similar to that used toproduce lithium and sodium, with the exception that molten potassium chloride (which meltsat about 770°C) is used to produce potassium metal at the cathode. | | 特性 | Because its outer valence electrons are at a greater distance from its nuclei, potassium ismore reactive than sodium or lithium. Even so, potassium and sodium are very similar in theirchemical reactions. Due to potassium’s high reactivity, it combines with many elements, particularly nonmetals. Like the other alkali metals in group 1, potassium is highly alkaline (caustic) with a relatively high pH value. When given the flame test, it produces a violet color. | | 来歴 | Discovered in 1807 by Davy, who obtained
it from caustic potash (KOH); this was the first metal isolated
by electrolysis. The metal is the seventh most abundant and
makes up about 2.4% by weight of the Earth’s crust. Most potassium
minerals are insoluble and the metal is obtained from
them only with great difficulty. Certain minerals, however,
such as sylvite, carnallite, langbeinite, and polyhalite are found
in ancient lake and sea beds and form rather extensive deposits
from which potassium and its salts can readily be obtained. Potash is mined in Germany, New Mexico, California, Utah,
and elsewhere. Large deposits of potash, found at a depth of
some 1000 m in Saskatchewan, promise to be important in
coming years. Potassium is also found in the ocean, but is
present only in relatively small amounts compared to sodium.
The greatest demand for potash has been in its use for fertilizers.
Potassium is an essential constituent for plant growth
and it is found in most soils. Potassium is never found free in
nature, but is obtained by electrolysis of the hydroxide, much
in the same manner as prepared by Davy. Thermal methods
also are commonly used to produce potassium (such as by reduction
of potassium compounds with CaC2, C, Si, or Na). It is
one of the most reactive and electropositive of metals. Except
for lithium, it is the lightest known metal. It is soft, easily cut
with a knife, and is silvery in appearance immediately after a
fresh surface is exposed. It rapidly oxidizes in air and should
be preserved in a mineral oil. As with other metals of the alkali
group, it decomposes in water with the evolution of hydrogen.
It catches fire spontaneously on water. Potassium and
its salts impart a violet color to flames. Twenty-one isotopes,
one of which is an isomer, of potassium are known. Ordinary
potassium is composed of three isotopes, one of which is 40K
(0.0117%), a radioactive isotope with a half-life of 1.26 × 109
years. The radioactivity presents no appreciable hazard. An
alloy of sodium and potassium (NaK) is used as a heat-transfer
medium. Many potassium salts are of utmost importance,
including the hydroxide, nitrate, carbonate, chloride, chlorate,
bromide, iodide, cyanide, sulfate, chromate, and dichromate.
Metallic potassium is available commercially for about $1200/
kg (98% purity) or $75/g (99.95% purity). | | 使用 | Some of the most common compounds in 19th century
photography were made with this silvery metallic element
discovered by Sir Humphrey Davy in 1807. There is not
enough room in this work to list all of these compounds, but
the following represent a reasonable sampling. | | 使用 | Liquid potassium, when mixed with liquid sodium (NaK), is an alloy used as a heatexchange substance to cool nuclear reactors. Potassium is an important reagent (something that is used in chemical reactions to analyze other substances) that forms many compounds used in chemical and industrial laboratories. It is used to manufacture both hard and soft soaps, as a bleaching agent, and where a highly caustic chemical is required. Potassium is essential to all living organisms. It is a trace element required for a healthy diet and is found in many foods. One natural source is bananas. | | 使用 | Potassium is used in the manufacture ofmany reactive potassium salts, in organicsynthesis, and as a heat exchange fluid whenalloyed with sodium. | | 使用 | In synthesis of inorganic potassium Compounds; in organic syntheses involving condensation, dehalogenation, reduction, and polymerization reactions. As heat transfer medium together with sodium: Chem. Eng. News 33, 648 (1955). Radioactive decay of 40K to 40Ar used as tool for geological dating. | | 定義 | potassium: Symbol K. A soft silverymetallic element belonging to group1 (formerly IA) of the periodic table(see alkali metals); a.n. 19; r.a.m.39.098; r.d. 0.86; m.p. 63.7°C; b.p.774°C. The element occurs in seawaterand in a number of minerals,such as sylvite (KCl), carnallite(KCl·MgCl2·6H2O), and kainite(MgSO4·KCl·3H2O). It is obtained byelectrolysis. The metal has few usesbut potassium salts are used for awide range of applications. Potassiumis an essential element for livingorganisms. The potassium ion,K+, is the most abundant cation inplant tissues, being absorbed throughthe roots and being used in suchprocesses as protein synthesis. In animalsthe passage of potassium andsodium ions across the nerve-cellmembrane is responsible for thechanges of electrical potential thataccompany the transmission of impulses.Chemically, it is highly reactive,resembling sodium in itsbehaviour and compounds. It alsoforms an orange-coloured superoxide,KO2, which contains the O2- ion.Potassium was discovered by SirHumphry Davy in 1807. | | 製造方法 | Potassium metal is not produced commercially by a fused salt electrolysis of the chloride
—as is sodium—for several reasons: the metal is too soluble in the molten chloride to
separate and float on top of the bath; potassium metal vapors may also issue from the
molten bath, thus creating hazardous conditions; and potassium superoxide may form in the
cell and react explosively with potassium metal. Consequently, the established method of
preparing potassium metal commercially? involves the reduction of molten potassium
chloride by metallic sodium at elevated temperatures (850°C). Molten potassium chloride
is fed into the midpoint of a steel vessel provided with a fractionating tower packed with
stainless steel rings. Sodium is vaporized at the bottom and rises countercurrent to the
molten potassium chloride with which it reacts according to the equilibrium expression.
Although the left-hand side of the equation is favored thermodynamically, the escape of the
potassium vapors causes the reaction to proceed very efficiently to the right. The potassium
vapors are condensed and the product normally contains sodium metal as the only major
impurity up to about 1 % by weight. This product is sometimes purified by fractionating it in
a 38 ft high 316 stainless steel tower equipped with a reflux return reservoir. The condensate
is potassium metal of 99.99 % purity. | | 調製方法 | Potassium superoxide
(KO2) can create oxygen from water vapor (H2O) and carbon
dioxide (CO2) and is used in respiratory equipment and is
produced by burning potassium metal in dry air. | | 一般的な説明 | Potassium is potassium mixed with some other metal, usually sodium. Potassium is a liquid under normal conditions. Potassium reacts vigorously with water to form potassium hydroxide, a corrosive material and hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. Potassium alloy may ignite spontaneously in contact with air. Once ignited, potassium burns quite violently. Potassium is used as a heat exchange fluid. | | 空気と水の反応 | Reacts vigorously with oxygen. Reacts vigorously with water even at less than 100°C [Merck, 11th ed., 1989]. Water (caustic solution, H2) The oxidation of potassium in air is so rapid that the heat generated by the reaction melts and ignites the metal. This is particularly the case when pressure is applied at ordinary temperatures [Sidgwick 1. 1950]. Potassium burns in moist air at room temperature [Mellor 2:468. 1946-47]. The higher oxides of potassium, formed in air, react explosively with pure potassium, sodium, sodium-potassium alloys, and organic matter [Mellor 2, Supp. 3:1559. 1963]. | | 反応プロフィール | Boron trifluoride reacts with incandescence when heated with alkali metals or alkaline earth metals except magnesium [Merck 11th ed. 1989]. Maleic anhydride decomposes explosively in the presence of alkali metals . Sodium peroxide oxidizes antimony, arsenic, copper, potassium, tin, and zinc with incandescence . Alkali metal hydroxides, acids, anhydrous chlorides of iron, tin, and aluminum, pure oxides of iron and aluminum, and metallic potassium are some of the catalysts that may cause ethylene oxide to rearrange and polymerize, liberating heat . Explosions occur, although infrequently, from the combination of ethylene oxide and alcohols or mercaptans [Chem. Eng. News 20:1318. 1942]. A mixture of potassium and any of the following metallic halides produces a strong explosion on impact: aluminum chloride, aluminum fluoride, ammonium fluorocuprate, antimony tribromide, antimony trichloride, antimony triiodide, cadmium bromide, cadmium chloride, cadmium iodide, chromium tetrachloride, cupric bromide, cupric chloride, cuprous bromide cuprous chloride, cuprous iodide, manganese chloride, mercuric bromide, mercuric chloride, mercuric fluoride, mercuric iodide, mercurous chloride, nickel bromide, nickel chloride, nickel iodide, silicon tetrachloride, silver fluoride, stannic chloride, stannic iodide (with silver), stannous chloride, sulfur dibromide, thallous bromide, vanadium pentachloride, zinc bromide, zinc chloride, and zinc iodide [Mellor 2, Supp. 3:1571. 1963]. A mixture of potassium and any of the following compounds produces a weak explosion on impact: ammonium bromide, ammonium iodide, cadmium fluoride, chromium trifluoride, manganous bromide, manganous iodide, nickel fluoride, potassium chlorocuprate, silver chloride, silver iodide, strontium iodide, thallous chloride, and zinc fluoride [Mellor 2, Supp. 3:1571. 1963]. A mixture of potassium and any of the following compounds may explode on impact: boric acid, copper oxychloride, lead oxychloride, lead peroxide, lead sulfate, silver iodate, sodium iodate, and vanadium oxychloride [Mellor 2, Supp. 3:1571. 1963]. A mixture of potassium with any of the following compounds produces a very violent explosion on impact: boron tribromide, carbon tetrachloride, cobaltous bromide, cobaltous chloride, ferric bromide, ferric chloride, ferrous bromide, ferrous chloride, ferrous iodide, phosphorus pentachloride, phosphorus tribromide, and sulfur dichloride [Mellor 2, Supp. 3:1571. 1963]. Mixture of solid potassium and carbon dioxide(as dry ice) explodes when subjected to shock [Mellor 2, Supp. 3:1568. 1963]. Potassium and its alloys form explosive mixtures with chlorinated hydrocarbons [Chem. Eng. News 26:2604. 1948]. Ethylene oxide is dangerously reactive with metallic potassium [Chemical Safety Data Sheet SD-38:11. 1951]. Potassium in contact with the following oxides causes an explosive reaction: potassium ozonide, potassium peroxide, or potassium superoxide [Mellor 2, Supp. 3:1577. 1963]. | | 危険性 | Elemental potassium as a metal is not found in its pure form in nature, but is derived fromits numerous compounds. The metal is very dangerous to handle. It can ignite while you areholding it with your hands or as you cut it. The metal must be stored in an inert gas atmosphereor in oil. Potassium fires cannot be extinguished with water—it only makes matters worsebecause it results in the formation of potassium hydroxide and hydrogen gas with enough heatto ignite the hydrogen. Dry chemicals such as soda ash, graphite, or dry sand can be used.
A particular hazard, which has been with humans since the beginning of time, is theradioactive isotope potassium-40 (K-40). Less than 1% of all potassium atoms on Earth arein the form of this radioactive isotope. It has a half-life of 1.25 billion years. Its decay process ends with the formation of the noble gas argon, which can then be analyzed to determine theage of rocks. This system (K-40 → argon) has been used to establish that the oldest rocks onEarth were formed about 3.8 billion years ago. Every living thing needs some potassium inits diet, including humans, who cannot escape this source of radiation, given that the humanbody cannot distinguish the radioactive potassium from the nonradioactive form. Along withcosmic rays and other naturally radioactive elements in the Earth’s crust, potassium-40 contributesto the normal lifetime accumulation of radiation. It makes up almost one-fourth ofthe total radiation the human body receives during a normal life span. | | 健康ハザード | Potassium reacts with the moisture on skin and other tissues to form highly corrosive potassium hydroxide. Contact of metallic potassium with the skin, eyes, or mucous membranes causes severe burns; thermal burns may also occur due to ignition of the metal and liberated hydrogen. | | 燃焼性と爆発性 | Potassium metal may ignite spontaneously on contact with air at room temperature.
Potassium reacts explosively with water to form potassium hydroxide; the heat
liberated generally ignites the hydrogen formed and can initiate the combustion of
potassium metal itself. Potassium fires must be extinguished with a class D dry
chemical extinguisher or by the use of sand, ground limestone, dry clay or graphite,
or "Met-L-X?" type solids. Water or CO2, extinguishers must never be used on
potassium fires. | | 使用用途 | カリウムはあらゆる物質と塩を形成し、そのカリウム塩は広く利用されています。例えば、硫酸塩 () と塩酸塩 () はカリ肥料として用いられ、硝酸塩 () は石鹸になります。
また、炭酸塩 (炭酸カリウム) は、 (ブラウン管、など) 、かんすいに使用可能です。その他、写真の製版 () 、花火、マッチ棒 (、塩素酸カリウム) に用いられています。
| | 农业用途 | Since the beginning of the 19th century, potassium has
been recognized as an essential element and a major
nutrient for plant growth, needed in large quantities. The
exact function of potassium is not fully understood.
Potassium makes plants more resistant to fimgal
diseases and insect attacks. It is good for healthy root
development and crop quality. For instance, potassium
improves the (a) texture, color and combustibility of
tobacco leaf, (b) sugar, starch and oil content in many
plants, and (c) taste, size and keeping quality of fruits.
Potato, tobacco and sugar use potassium, especially
during their early growth stages. A small quantity of
potassium is essential near young seedlings, while an
excessive quantity causes salt damage.
The requirement of potassium varies in growing
plants. Most seeds contain 0.1 to 10% potassium, which
is sufficient for germination and early growth. The
vegetative growth is characterized by a progressive
increase in the absorption of inorganic elements like
potassium. In tobacco, potassium is absorbed at the rate
of 0.1 kglhalday from the 2lst day of transplanting; a
maximum uptake of 2 kg/ha/day occurs 49 days after
transplanting. The minimum level of readily available
potassium in the soil is around 175 kg/ha.
Potassium is present in the cell sap solution or
plasma, and is almost fully extractable with water from
plant tissues. It accumulates at the site of cell division,
and helps in maintaining the physiological state of the
swelling of plasma colloids which is necessary for all
normal metabolic processes. It maintains the balance of
anabolism, respiration and transpiration of a plant or
leaf, and keeps the plant's water economy in equilibrium
(in turn, reducing the plant's tendency to wilt.)
Potassium has a very important role to play in plant
energy metabolism. Its liberal use helps to harden the
supporting tissues which, in turn, improves the keeping
qualities of fruits, and consequently leads to a stronger
structure.
Potassium does not become a part of the plant
structure as P, S, Ca and Mg do. But it helps in carbon
dioxide assimilation, translocation of proteins and
sugars, enzyme activity, cell division, reduction of
nitrates and fat synthesis. The influence of potassium in
these activities is now well established.
The levels of potassium and nitrogen are closely
related in most plants. Nitrogen stimulates the rapid growth of soft tissues, whereas potassium promotes the
growth of soft tissues. If sufficient potassium is
unavailable, nitrogen level increases in the outer leaves
of cabbage and in the upper stems and leaves of tomato.
In the sheath tissue of sugar cane, the relationship of
potassium to nitrogen depends on their respective
concentrations.
Ammonium has a greater depressing effect on
potassium in soil-grown plants than in solution, because
ammonium interferes with the diffusion of potassium
from the clay lattice. Potassium influences the uptake of
the two forms of nitrogen. The relative presence of K, Ca
and Mg influences the concentration of each individual
cation within the plant. In this, potassium seems to be the
most active. In plants, magnesium has a greater
depressing effect on the content of potassium than that of
calcium.
Because potassium ions (K+)an d sodium ions (Na+)
are similar in size and chemical properties, sodium may
replace potassium in several essential roles. However,
potassium is an essential element, whereas sodium is not.
Therefore, use of sodium may compensate for the
potassium shortage to some extent, but sodium will not
produce healthy plants in a situation when potassium
deficiency is large.
There is a close relationship between carbohydrates
and the potassium level. When soil potassium
concentration is insufficient for optimum growth, it is
commonly transported from more mature tissues to the
meristems, so that older leaves exhibit early deficiency
symptoms. Chlorosis appears first around the edges and
tips of the leaves, and then spreads to the mid rib,
followed finally by necrosis.
In many crops, potassium deficiency is characterized
by a contrast between chlorosis, necrosis and healthy
green areas of leaves. In the advanced stages of
potassium starvation in corn, leaf edges become necrotic,
the tissue disintegrates, and the leaf gets a ragged
appearance. This condition is called leaf scorch.
Potassium deficiency in alfalfa is seen as white spots on
the leaf edges, whereas chlorosis and necrosis of leaf
edges are observed in other grasses.
Potassium deficiency can also occur among young
upper leaves in some high-yielding , fast-maturing crops
like cotton and wheat. Insufficient potassium weakens the
straw in grain crops, causes lodging in small grains and
stalk breakage in corn and sorghum. Potassium
deficiencies greatly reduce crop yield. A phenomenon in
which deficiency symptoms are not visible is called
hidden hunger. Potassium stress increases the degree of
crop damage by bacterial and fungal diseases, insect and
mite infestation, and nematode and virus infection. Lack
of potassium in wetland rice greatly increases the
sensitivity of foliar diseases such as stem rot, sheath
blight and brown leaf spot.
Soil humus is a major source of sulphur, but not of
potassium. Potassium ion is a highly soluble cation in
solution, but it moves slowly in soils (unlike sulphur
which is soluble and a readily mobile sulphate ion).
Diffusion and mass flow of potassium to plant roots
account for a large portion of absorbed potassium. In
decaying humus, the potassium ion is fust leached into
the soil solution and then to cation exchange sites on the
humus and clay particles. A non-decomposed organic
mass added to the soil replaces large amounts of
potassium which flows with the water to the roots.
In plant cells, potassium is the most abundant metal
cation. On decomposition, fresh plant residues give all
the potassium the plant needs for growth as a mobile
soluble ion. Soluble potassium can be immobilized into
the bodies of microbes, lost in leaching waters, or held
between layers of hydrous mica and similar clays during
drying. High yielding crop plants take potassium ions
from a small reservoir of readily available potassium,
namely the exchangeable source. For a good crop, at
least 170 to 200 kg/ha potassium is considered essential.
Soluble potassium may suffice if the soil is neutral or
basic.
Using potassium fertilizers in excess, or too
frequently, may result in an excess uptake of potassium
by plants and in lowering their potassium-magnesium
absorption. The effectiveness of the soil solutionpotassium
for crop uptake is influenced by the presence
of other cations, especially Na, Ca, Mg and Al. The
absorption of potassium, in excess of that required for
optimum growth, results in the accumulation of the
nutrient without a corresponding increase in the growth,
and is known as luxury consumption. The exchangeable
or water-soluble potassium is converted by the
potassium furation process to a form, not easily
exchangeable from the adsorption complex, by a cation
of a neutral salt solution. | | 安全性プロファイル | The toxicity of
potassium compounds is almost always that
of the anion, not of potassium. A dangerous
fire hazard. Metallic potassium reacts with
moisture to form potassium hydroxide and
hydrogen. The reaction evolves much heat,
causing the potassium to melt and spatter.
The reaction also ignites the hydrogen,
which burns, or if there is any confinement, may explode. It can ignite spontaneously in
moist air. Store under mineral oil. Potassium
metal wdl form the peroxide (K2O2) and the
superoxide (KO3 or K2O4) at room
temperature even when stored under
mineral oil. These oxides can explode on
contact with organic materials. Metal that
has oxidized on storage under oil may
explode violently when handled or cut.
Oxide-coated potassium should be
destroyed by burning.
Danger: burning potassium is difficult to
extinguish; dry powdered soda ash or
graphte or special mixtures of dry chemical
are recommended.
A violent explosion hazard with the
following materials under required
conditions of temperature, pressure, and
state of division: acetylene, air, moist air,
alcohols (e.g., n-propanol through n-octanol,
benzyl alcohol, cyclohexanol), AlBr3,
ammonium nitrate + ammonium sulfate,
ammonium chlorocuprate, NHdi, NH41,
antimony halides, arsenic hahdes, AsH3 +
NH3, Bi203, boric acid, BBr3, carbon
disulfide (impact-sensitive), solid carbon
dioxide, carbon monoxide, chlorinated
hydrocarbons (e.g., chloroethane,
dichloroethane, dchloromethane,
trichloroethane, chloroform, pentachloro-
ethane, carbon tetrachloride, tetrachloro-
ethane), halocarbons (e.g., bromoform,
dbromomethane, diiodomethane) , iodme
(impact-sensitive), interhalogens (e.g.,
chlorine trifluoride, iodine bromide, iodine
chloride, iodine pentafluoride, iodme
trichloride), ClO, CrO3, Cu2OCl2, CuO,
ethylene oxide, fluorine, graphite, graphte +
air, graphite + K2O2, hydrogen iodide,
H2O2, hydrogen chloride, hydrazine,
Pb2OCl2, PbO2, PbSO4, maleic anhydride,
metal halides (e.g., calcium bromide,
iron(Ⅲ) bromide, iron(Ⅲ) chloride, iron(Ⅱ)
chloride, iron(Ⅱ) bromide, iron(Ⅱ) iodide,
cobalt(Ⅱ) chloride, chromium tetrachloride,
silver fluoride, mercury(Ⅱ) bromide,
mercury(Ⅱ) chloride, mercury(Ⅱ) fluoride,
mercury(Ⅱ) iodide, copper0 chloride,copper(Ⅰ) iodde, copper(Ⅱ) bromide,
copper(Ⅱ) chloride, ammonium
tetrachlorocuprate, zinc chlorides, bromides,
or ioddes, cadmium chlorides, bromides or
iodides, aluminum fluorides, chlorides, or
bromides, thalliump) bromide, tin chlorides,
tin iodide, arsenic trichloride, arsenic
triiodde, antimony tribromides, trichlorides
or triiodides, bismuth tribromides,
trichlorides, or triioddes, vanadiumo
chloride, manganese(Ⅰ) chloride, nickel
bromide, chloride, or iodide), metal oxides
(e.g., lead peroxide, mercury(Ⅰ) oxide,
MoO3, nitric acid, nitrogen-containing
explosives (e.g., ammonium nitrate, picric
acid, nitrobenzene), nonmetal halides (e.g.,
diselenium dichloride, seleninyl chloride,
seleninyl bromide, sulfur dichloride, sulfur
dibromide, phosphorus tribromide,
phosphorus trichloride, phosgene, disulfur
dichloride), nonmetal oxides (e.g., dichlorine
oxide, dinitrogen tetraoxide, dinitrogen
pentaoxide, NO2, P2O5), oxalyl dibromide,
oxalyl dichloride, P2NF, peroxides, COCl2,
PH3 + NH3, phosphorus, PCl5, PBr3,
potassium chlorocuprate, potassium oxides
(e.g., KO3, K2O2, KO2), selenium, SeOCl2,
SiCl4, AglO3, NalO3, NH3 + NaNO2,
Na2O2, SnI4 + S, SnO2, S, sulfuric acid,
tellurium, thiophosphoryl fluoride, VOCl2,
water.
Other hazardous reactions may occur
with carbon (e.g., soot, graphte, activated
charcoal), dimethyl sulfoxide, ethylene
oxide, chlorine, bromine vapor, hydrogen
bromide, potassium iodide + magnesium
bromide, chloride or iodide, maleic
anhydride, mercury, copper(Ⅱ) oxide,
mercury(Ⅱ) oxide, tin(Ⅳ) oxide,
molybdenum(Ⅲ) oxide, bismuth trioxide,
phosphorus trichloride, sulfur dioxide,
chromium trioxide.
toxic fumes of K2O.
When heated to decomposition it emits | | 職業ばく露 | Used as a reagent and in sodiumpotassium alloys which are used as high-temperature heat transfer media. | | 概要 | カリウムとは、原子番号19番の元素で、1属のアルカリ金属です。
1807年にイギリスの化学者ハンフリー・デイビーによって、初めて単離されました。カリウムは植物の成長に必要な必須元素であり、窒素やリンとともに肥料の三大要素の1つです。
また、人体に必要なミネラルの1種であり、細胞内液の浸透圧の調整などの働きをしています。極めて反応性に富んでいるため、自然界では化合物の形で存在しており、単体の形では存在しません。
| | 環境運命予測 | Potassium metal in the environment will react with air,
oxidizing the exposed surfaces, and reacts violently with water,
yielding potassium hydroxide and hydrogen gas, which reacts
with oxygen in air, producing flame. | | 貯蔵 | Safety glasses,
impermeable gloves, and a fire-retardant laboratory coat should be worn at all times
when working with potassium, and the metal should be handled under the surface of
an inert liquid such as mineral oil, xylene, or toluene. Potassium should be used only
in areas free of ignition sources and should be stored under mineral oil in tightly
sealed metal containers under an inert gas such as argon. Potassium metal that has
formed a yellow oxide coating should be disposed of immediately; do not attempt to
cut such samples with a knife since the oxide coating may be explosive. | | 輸送方法 | UN2257Potassium, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material. UN1420 Potassium, metal alloys and metal alloys, liquid, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material. UN3089 Metal powder, flammable, n.o.s. Hazard Class: 4.2; Labels: 4.2-Spontaneously combustible material. | | Toxicity evaluation | Potassium is a cofactor and activates a large variety of enzymes,
including glycerol dehydrogenase, pyruvate kinase, L-threonine
dehydrase, and ATPase. Its acute toxicity is primarily due to its
action as an electrolyte. Excessive or diminished potassium
levels can disrupt membrane excitability and influence muscle
cell contractility and neuronal excitability. | | 不和合性 | Air contact causes spontaneous ignition. Violent reaction with water, forming heat, spattering, corrosive potassium hydroxide and explosive hydrogen. The heat from the reaction can ignite the hydrogen that is generated. A powerful reducing agent. Violent reaction with oxidizers, organic materials; carbon dioxide; heavy metal compounds; carbon tetrachloride; halogenated hydrocarbons; easily oxidized materials; and many other substances. Store under nitrogen, mineral oil, or kerosene. Oxidizes and forms unstable peroxides under storage conditions. Potassium metal containing an oxide coating is an extremely dangerous explosion hazard and should be removed by an expert and destroyed. | | 廃棄物の処理 | Excess potassium and waste material containing this substance should be placed in an appropriate container
under an inert atmosphere, clearly labeled, and handled according to your institution's waste disposal
guidelines. Experienced personnel can destroy small scraps of potassium by carefully adding t-butanol or nbutanol
to a beaker containing the metal scraps covered in an inert solvent such as xylene or toluene. |
|