酸素 化学特性,用途語,生産方法
定義
本品は、地球の大気の約21%を占める2原子分子からなる気体である。
解説
酸素，元素記号はO。原子番号８，原子量15.99903〜15.99977。融点−218.4℃，沸点−182.96℃。周期表第VI族に属し，酸素族元素の一つ。1774年プリーストリーとシェーレが独立に発見。単体は２原子分子O2が普通で，無色無臭の気体。液体，固体では淡青色。化学的にはきわめて活性で多くの元素と直接反応して酸化物をつくり，乾燥気中で無声放電を行うとオゾンO3となる。生物の呼吸に関係し，各種燃料の燃焼に不可欠。高圧にしてボンベに入れ，吸入用，酸水素炎，酸素アセチレン炎などに使用。空気の主成分の一つ（約21容量％）。また水圏，岩石圏の主要構成元素の一つで，地球表面には最も多量に存在する（クラーク数46.4）。工業的には液体空気の分留または水の電解によってつくる。金属精錬への用途は，工業的に重要。
用途
溶接用酸素
用途
最大の用途は鉄鋼業における酸素製鋼で、ほかに化学工業・石油化学工業での酸素酸化、造船・機械工業での酸素切断、溶接用、医療用（酸素吸入）、活性汚泥法による水処理の曝気(ばっき)用などがある。
効能
医療用ガス
商品名
マルワ液酸 (和歌山酸素); 液体酸素 (エア・ウォーター); 液体酸素 (協栄高圧ガス); 液体酸素 (立川酸素); 液体酸素 (阿波酸素); 液化酸素 (Kist); 液化酸素 (アバンテ都島); 液化酸素 (イビデンケミカル); 液化酸素 (イワサワ); 液化酸素 (エア・ガシズ北九州); 液化酸素 (エアーメディックス); 液化酸素 (エバ); 液化酸素 (オカノ); 液化酸素 (ガステックサービス); 液化酸素 (伊藤忠工業ガス); 液化酸素 (共同高圧ガス工業); 液化酸素 (内村酸素); 液化酸素 (因の島ガス); 液化酸素 (大丸エナウィン); 液化酸素 (大島商会); 液化酸素 (宇野酸素); 液化酸素 (小池メディカル); 液化酸素 (岡谷酸素); 液化酸素 (日本エア・リキード); 液化酸素 (昭和電工ガスプロダクツ); 液化酸素 (水島酸素商会); 液化酸素 (江藤酸素); 液化酸素 (福岡酸素); 液化酸素 (秋酸工業); 液化酸素 (茨城ガスセンター); 液化酸素 (鹿児島酸素); 酸素 (Kist); 酸素 (アバンテ都島); 酸素 (イビデンケミカル); 酸素 (イワサワ); 酸素 (エア・ウォーター); 酸素 (エア・ガシズ北九州); 酸素 (エアーメディックス); 酸素 (エバ); 酸素 (オカノ); 酸素 (ガステックサービス); 酸素 (伊藤忠工業ガス); 酸素 (共同高圧ガス工業); 酸素 (内村酸素); 酸素 (協栄高圧ガス); 酸素 (和歌山酸素); 酸素 (大島商会); 酸素 (宇野酸素); 酸素 (小池メディカル); 酸素 (岡谷酸素); 酸素 (日本エア・リキード); 酸素 (春日井ガスセンター); 酸素 (水島酸素商会); 酸素 (江藤酸素); 酸素 (泉産業); 酸素 (福岡酸素); 酸素 (秋酸工業); 酸素 (立川酸素); 酸素 (茨城ガスセンター); 酸素 (阿波酸素); 酸素 (鹿児島酸素)
酸素の発見
古代、空気は元素であると考えられていたが、10世紀ごろからは混合物であるとされ始めた。そして17世紀には空気が2種類の気体の集まりであり、一つは硝石から得られ、もう一つは不活性な気体であることが明らかにされるようになった。スウェーデンのシェーレは1771年ころ硝酸カリウム（硝石）を熱して、イギリスのプリーストリーは1774年に集光レンズで太陽光線を集め、ガラス鐘の中の酸化水銀に当てて酸素を取り出した。しかし、2人ともフロギストン説（物が燃えるのはフロギストンが逃げていくという説）の信奉者であったため、新ガスが普通の空気に比べ著しく燃焼を支持することから、シェーレは「火の空気」、プリーストリーは「脱フロギストン空気」とよぶにとどまった。フランスのラボアジエは、金属を熱するときの重量増加は空気の一部分が固定されるためと考え、プリーストリーの実験と逆に、密閉器中で水銀を空気と熱して酸化水銀をつくり、空気の減りぐあいを調べ、さらに酸化水銀を熱して酸素を得ることを確認し、フロギストン説とまっこうから対立する新燃焼説を打ち立てた。ラボアジエは、1777年初めてこれが元素単体であることを明らかにして、この新しい気体中での燃焼生成物の多くが酸の性質を示すことから、ギリシア語のoxys（酸味のある）とgennao（生じる）からoxygèneと命名した。元素としての酸素の発見は化学史上きわめて重要なできごとで、これにより現代化学の礎(いしずえ)が築かれた。日本では宇田川榕菴(うだがわようあん)の『舎密開宗(せいみかいそう)』（1837）に「阿幾舎厄紐母（オキセイゲニユム）、酸素」と記されている。
存在
岩石中に約50重量％、水には約89重量％ほど含まれ、化合物として地殻（厚さ16キロメートル）、水圏中でもっとも多い元素である。また、遊離の状態すなわち酸素分子として大気中に21容量％も含まれる。宇宙では水素、ヘリウムに次いで3番目に多い。地球が生成したとき、酸素はすべて溶融状態で固定されていたと考えられ、やがて出現した緑色植物の光合成の副産物として供給され、現在のような大気ができたのは10億年前といわれている。大気中の酸素の同位体組成は16O：99.76％、18O：0.20％、17O：0.04％である。90％（原子数）以上に濃縮された18Oは重酸素とよばれ、トレーサー実験に利用される。
性質
常温常圧で無色、無味、無臭の気体。二原子分子O2は2個の不対電子をもち常磁性である。無声放電または遠紫外線の照射でオゾンO3を生じる。きわめて活性な元素で、軽い希ガスを除きすべての元素との化合物が知られ、多くの元素と直接反応する。たとえば、炭素、硫黄(いおう)、リンなどは酸素中で激しく燃え、アルミニウム、鉄、銅なども粉末状態では閃光(せんこう)を発して燃える。希ガス、ハロゲン、金、白金などの貴金属とは直接反応しない。動植物の生活と密接な関係があり、酸素なくしては生命は保たれない。
説明
Oxygen is a very prevalent and important element and is
necessary for sustaining life on this planet. This element is the
third most abundant in mass behind helium and hydrogen in
the universe. The diatomic form (O2) is the most common pure
form. With a boiling point at -183 °C, O2 exists as a colorless
and odorless gas at standard temperature and pressure. In the
process of cellular respiration, the highly reactive O2 is used as
the oxidant in breaking down food molecules to produce
energy. In turn, photosynthetic organisms generate O2 by using
energy from the sun and water. Other allotropes of pure oxygen
exist, including the trioxygen (O3) form known as ozone, as
well as other, less common allotropes of oxygen such as O4 and
O8. These oxygen allotropes are formed under high pressure
and low temperatures and are solid.
化学的特性
Oxygen, O2, is a colorless, tasteless, gaseous element essential to almost all forms of life. It promotes respiration and combustion. Oxygen comprises 20% of the earth's atmosphere and is the most abundant element in seawater and in the earth's crust. It is slightly soluble in water and alcohol, but combines readily with most other elements to form oxides. The electrolysis of water produces both oxygen and hydrogen.
物理的性質
There are three allotropes (different forms) of oxygen: (1) atomic oxygen (O), sometimesreferred to as nascent or “newborn” oxygen; (2) diatomic oxygen (O
2), or molecular oxygen(gas); and (3) ozone (O
3), also a gas.
The atmospheric oxygen that we breathe is a very reactive nonmetal and is colorless, odorless,and tasteless, but it is essential to all living organisms. It readily forms compounds withmost other elements. With six electrons in its outer valence shell, it easily gains two moreelectrons to form a negative (–2) ion; or as covalent, it can share electrons with other elementsto complete its outer shell.
Almost all the oxygen in the atmosphere (?21%) is the allotropic form of molecular oxygen(O
2). This essential gas we breathe is the result of photosynthesis, which is how green plants(with chlorophyll) use the energy of the sun to convert carbon dioxide (CO
2) and water tostarches and sugars with molecular oxygen as the by-product.
Liquid oxygen has a slightly bluish cast to it. As it boils, pure oxygen gas is released. Themelting point for oxygen is –218.79°C, its boiling point is –182.95°C, and its density is0.001429 g/cm
3.
同位体
There are a total of 15 isotopes of oxygen, three of which are stable. The stableones are O-16, which accounts for 99.762% of all the oxygen on Earth; O-17, whichcontributes only 0.038% of the Earth’s oxygen; and O-18, which makes up just 0.200%of Earth’s oxygen.
特性
Oxygen is, without a doubt, the most essential element on Earth. It is required to supportall plant and animal life, and it forms more compounds with other elements than any otherelement.
Oxygen is soluble in both water and alcohol. Contrary to what many people believe, oxygenis NOT combustible (it will not burn), but rather it actively supports the combustion ofmany other substances. After all, if oxygen burned, every time a fire was lit, all the O
2 in theatmosphere would be consumed!
Burning is a form of oxidation wherein oxygen chemically combines with a substance rapidlyenough to produce adequate heat to cause fire and light, or to maintain a fire once started.The oxidation of iron is called rusting. Rusting in an example of “slow oxidation,” which isthe reaction of O
2 with Fe to form Fe
2O
3 or Fe
3O
4. This chemical reaction is so slow that theheat it produces is dissipated; thus, there is no fire.
Recently a new allotrope of oxygen was discovered. When O
2 is subjected to great pressure,it is converted intoO
4, which is a deep red solid that is a much more powerful oxidizer thanthe other forms of oxygen.
使用
Oxygen has many uses due to its high electronegativity with the ability to oxidize manyother substances. Only fluorine has higher electronegativity and is thus a stronger oxidizer.Besides the essential use to support life, oxygen has many other uses.
It is used in the smelting process to free metals from their ores. It is particularly importantin the oxygen-converter process in the production of steel from iron ore.
Oxygen is used in making several important synthetic gases and in the production ofammonia, methyl alcohol, and so on.
It is the oxidizer for liquid rocket fuels, and as a gas, oxygen is used in a mixture withhelium to support the breathing of astronauts and divers and to aid patients who have difficultybreathing. It is use to treat (oxidize) sewage and industrial organic wastes.
Oxygen has many uses because of its ability to accept electrons from other elements to formionic bonds or to share electrons with other elements to form covalent bonds.
調製方法
Oxygen is the most prevalent element in the Earth’s crust,
making up 49.2% by weight. It accounts for 20.95% by
volume of the Earth’s atmosphere and approximately 65% by
weight of the human body.
定義
Dioxygen: the normal form of molecularoxygen, O
2, used to distinguishit from oxygen atoms or fromozone （O
3）.
製法
工業的に、酸素は液体空気の分留により窒素と同時に製造される。小型の製造法として、空気からモレキュラーシーブによる吸脱着を利用した分離法や、水電解による方法がある。実験室では、塩素酸カリウムに触媒として半量くらいの二酸化マンガンを混ぜて熱する（有機物が混入すると爆発しやすい）。ほかに、二酸化マンガンを触媒とする過酸化水素の分解、あるいは水の電解、また過マンガン酸カリウムを真空中加熱分解させる方法がある。市販品は液体酸素としてタンクローリーあるいはボンベ入りで取り扱われ、ボンベの色は黒である。全低圧式の酸素と窒素の製造工程については図を参照。
一般的な説明
Oxygen is a colorless, odorless and tasteless gas. Oxygen will support life. Oxygen is noncombustible, but will actively support the burning of combustible materials. Some materials that will not burn in air will burn in Oxygen. Materials that burn in air will burn more vigorously in Oxygen. As a non-liquid gas Oxygen is shipped at pressures of 2000 psig or above. Pure Oxygen is nonflammable. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. Oxygen is used in the production of synthesis gas from coal, for resuscitation and as an inhalant.
反応プロフィール
Propellant; ignites upon contact with alcohols, alkali metals, amines, ammonia, beryllium alkyls, boranes, dicyanogen, hydrazines, hydrocarbons, hydrogen, nitroalkanes, powdered metals, silanes, or thiols [Bretherick 1979. p.174]. Heat of water will vigorously vaporize liquid Oxygen, pressures may build to dangerous levels if this occurs in a closed container. Liquid Oxygen gives a detonable mixture when combined with powdered aluminum [NFPA 491M. 1991].
危険性
Although oxygen itself is not flammable or explosive, as is sometimes believed, its mainhazard is that, in high concentrations, oxygen can cause other materials to burn much morerapidly.
Oxygen is toxic and deadly to breathe when in a pure state at elevated pressures. In addition,such pure oxygen promotes rapid combustion and can produce devastating fires, such asthe fire that killed the Apollo 1 crew on a test launch pad in 1967. It spread rapidly because thepure oxygen was at normal pressure rather than the one-third pressure used during flight.
Oxygen used for therapeutic purposes in adults can cause convulsions if the concentrationis too high. At one time, high levels of oxygen were given to premature infants to assist theirbreathing. It was soon discovered that a high concentration of O2 caused blindness in some ofthe infants. This practice has been abandoned, or the oxygen levels have since been reduced,and this is no longer a medical problem.
Oxygen involved in metabolic processes are prone to form “free radicals,” which arethought to cause damage to cells and possibly be associated with cancer and aging.
健康ハザード
Inhalation of 100% Oxygen can cause nausea, dizziness, irritation of lungs, pulmonary edema, pneumonia, and collapse. Liquid may cause frostbite of eyes and skin.
火災危険
Behavior in Fire: Increases intensity of any fire. Mixtures of liquid Oxygen and any fuel are highly explosive.
燃焼性と爆発性
Oxygen itself is nonflammable, but at concentrations greater than 25% supports and
vigorously accelerates the combustion of flammable materials. Some materials
(including metals) that are noncombustible in air will burn in the presence of oxygen.
农业用途
Oxygen (O) is an odorless, colorless, gaseous element
that belongs to group 16 (formerly group VI) of the
Periodic Table. It is the most abundant element
in the earth's crust (49.2% by weight), is present in the
atmosphere (20% by volume) and is a constituent of
water. It exists in three isotopes 16, 17 and 18. Oxygen is
essential for respiration of most living organisms and for
combustion. It is used in metallurgical processes, in high
temperature flames (welding) and in medical treatment.
The common form of oxygen is di-atomic oxygen
(O
2) There is also another form - reactive allotrope
ozone (O
3)C.h emically, oxygen reacts with most other
elements forming oxides. For industrial use, it is
obtained by fractional distillation of liquid air. This has
been replaced by a process which utilizes ambient
temperature separation by means of a pressure cycle in
which molecular sieves of synthetic zeolite preferentially
absorb nitrogen from air, giving 95 % oxygen and 5 %
argon.
The most popular industrial use of oxygen is in
oxygen enrichment of steel blast furnaces. Large
quantities of oxygen are used in the synthesis of nitric
acid from ammonia, methanol and ethylene oxide, as also
in oxy-acetylene welding.
職業ばく露
Compressed oxygen is used in various
oxidation processes, for feedstock; and enrichment purposes;
as a medicinal gas; a chemical intermediate; in oxyacetylene
welding; in metallurgy. Liquid oxygen is used as
a rocket fuel. Oxygen is naturally present at a concentration
of 21% in breathing air.
発がん性
Exposure to ionizing radiation is
recognized as a cause of cancer, and the production of
free radicals in the exposed cells is a part of the process.
If hyperoxia causes free radical formation, it may contribute
to the occurrence of cancer. Although a direct relation of
hyperoxic injury and cancer has not been proven, numerous
instances of association in experimental animals exist. Reactive
oxidative intermediates have been shown to cause chromosome
breaks and damage to DNA that can initiate
carcinogenesis.
Experimental work done with mouse skin tumors (as
models of human tumors) has been both revealing and
confusing. A substance may act as a cancer initiator or as
a promoter, or sometimes both, depending on intensity and
duration of exposure, and the presence of other carcinogenic
materials. The same substance can also inhibit cancer
growth. Hyperoxia has clearly been involved in modifying
the course of tumor development, but the effects have
differed under varying circumstances.
環境運命予測
Atmospheric air contains 20.8% O2. Despite consumption of
O2 through respiration and oxidative processes, this concentration
remains constant, most likely due to the depleted O2
being replaced by plant-generated O2 in the photosynthetic
process. O2 does not bioaccumulate in organisms as pure
oxygen.
輸送方法
UN1072 Oxygen, compressed & UN1073
Oxygen, refrigerated liquid (cryogenic liquid), Hazard
Class: 2.2; Labels: 2.2-Nonflammable compressed gas; 5.1-
Oxidizer. Cylinders must be transported in a secure upright
position, in a well-ventilated truck. Protect cylinder and
labels from physical damage. The owner of the compressed
gas cylinder is the only entity allowed by federal law
(49CFR) to transport and refill them. It is a violation of
transportation regulations to refill compressed gas cylinders
without the express written permission of the owner.
純化方法
Purify it by passing the gas over finely divided platinum at 673oK and Cu(II) oxide (see under nitrogen) at 973o, then condensed in a liquid N2-cooled trap. HIGHLY EXPLOSIVE in contact with organic matter.
不和合性
A strong oxidizer. Reacts violently with
nearly every element, combustibles, organics, and reducing
materials.
廃棄物の処理
Return refillable compressed
gas cylinders to supplier. Vent to atmosphere.
酸素 上流と下流の製品情報
原材料
準備製品