酸化二窒素 化学特性,用途語,生産方法
解説
酸化二窒素，室温で無色の気体．融点－90.9 ℃，沸点－88.6 ℃．液体，固体ともに無色．N-N-O直線構造(N-N0.112 nm，N-O0.119 nm)で双極子モーメント0.17 D．室温では化学的に安定である．海洋や土壌，窒素肥料や工業活動により大気中に放出され，大きな温室効果をもつ気体である．年々大気中の濃度は増加しており，一酸化窒素とともに大気汚染物質としての窒素酸化物(NOx)のおもなものである．高温では分解して酸素を放出し，金属，炭素，硫黄，リンなどとはげしく反応する．水に多少溶けるが次亜硝酸とはならない．麻酔性をもち，吸入すると顔の筋肉をけいれんさせ，笑ったように見えるので笑気ともよばれる．吸入麻酔薬として用いられる．また，半導体の製造にも用いられる．
森北出版「化学辞典（第2版）
原理
亜酸化窒素は、常温だと特徴的な臭気をもつ無色の気体で、分子構造としては図1のような共鳴構造をとっています。不燃性で安定した気体で、他の窒素酸化物のような毒性はありません。特徴として麻酔作用、鎮痛作用があり、吸入すると顔面の筋肉が痙攣してしまい笑っているようにみえるところから、笑気ガスと呼ばれています。吸入式の全身麻酔に使用します。
650℃に加熱すると分解してNOxの蒸気を生成し、火災や爆発の危険をもたらします。無水亜硫酸、無定形ホウ素、、エーテル、、、フェニルリチウム、など還元剤およびある種の可燃性物質などと激しく反応し、火災や爆発の可能性があるため、大変危険です。
また、この気体は 300℃以上の強酸化剤であり、、、油などと爆発性混合物を生成することがあります。吸入すると多幸感が得られるとされ脱法ドラックとして乱用されたため、現在は指定薬物です。
用途
そのまま、又は酸素と混ぜて歯科及び外科、産婦人科の麻酔用に多く用いられる。また漏えい検知用、冷媒、原子吸光のキャリアガスにも用いられる。食品添加物(ホイップクリーム類の起泡剤)
製造
酸化二窒素，亜酸化窒素ともいう．硝酸アンモニウムの熱分解でつくられる．
効能
吸入麻酔薬
商品名
アネスタ (星医療酸器); 亜酸化窒素 (和歌山酸素); 液化亜酸化窒素 (日本エア・リキード); 液化亜酸化窒素 (日産化学); 笑気 (小池メディカル); 笑気ガス (住友精化)
説明
dinitrogen monoxide’s (N2O)
common name is nitrous oxide.Nitrous oxide is a colorless, nonfl ammable,
nontoxic gas with a slightly sweet odor and taste. Nitrous oxide is produced by
the thermal decomposition of ammonium nitrate at approximately 240°C: NH4NO3(g) →
N2O(g) + 2H2O(g).Nitrous oxide is an important greenhouse gas.
Its atmospheric residence time is 120 years. A molecule of N2O has 310 times the potential
for absorbing heat compared to a molecule of CO2. Nitrous oxide is stable and unreactive on
the earth’s surface, but it can be transported to the stratosphere where it absorbs energy and is
converted into reactive forms of nitrogen such as nitric oxide and the nitrate radical contributing
to ozone destruction.
化学的特性
Nitrous oxide is a colorless gas. Slightly sweet
odor. Shipped as a liquefied compressed gas.
物理的性質
Colorless gas with faint sweet odor and taste; heavier than air, density in air 1.53 (air=1); gas density 1.977 g/L at 0°C; noncombustible gas; supports combustion; liquefies to a colorless liquid at -88.5°C; liquid density 1.226 g/mL at -89°C; freezes to a cubic crystalline solid at -90.8°C; dipole moment 0.166 ; critical temperature 36.5°C; critical pressure 71.7 atm; solubility in water: 130 mL gas dissolves in 100mL water at 0°C and 56.7 mL in 100 mL water at 25°C; soluble in alcohol, ether and sulfuric acid.
来歴
nitrous oxide was prepared in 1772 by Joseph Priestley (1733 1804) . Priestley called nitric oxide nitrous air, nitrogen dioxide nitrous acid vapor, and nitrous oxide phlogisticated nitrous air, but also referred to the dioxide. Priestley prepared nitric oxide by reacting nitric acid with a metal such as copper: 3Cu(s) + 8HNO3(aq) 2NO(g) + 3Cu(NO3)2(aq) + 4H2O(l).He prepared nitrous oxide by reducing nitric oxide using iron: 2NO(g) + H2O(l) + Fe(s) N2O(g) + Fe(OH)2(aq).For example, the year of discovery for nitrous oxide ranges between 1772 and 1793. Humphrey Davy (1778 1829) examined the physiological effects of nitrous oxide and in 1799 wrote Researches Chemical and Philosophical, Chiefly Concerning Nitrous Oxide.
使用
Nitrous oxide was discovered by Priestley. It is found in the atmosphere in trace concentrations. The gas is used as an anesthetic, especially in dentistry and minor surgery. It produces mild hysteria and laughter preceding the anesthetic effect, for which reason it also is called “laughing gas.” It is used as an aerosol propellant, an aerating agent for whipped cream, and an oxidizing agent at high temperatures. Nitrous oxide also is used in the preparation of nitrites and as a flame gas in flame atomic absorption spectrometry of metals.
定義
ChEBI: A nitrogen oxide consisting of linear unsymmetrical molecules with formula N2O. While it is the most used gaseous anaesthetic in the world, its major commercial use, due to its solubility under pressure in vegetable fats combined with
ts non-toxicity in low concentrations, is as an aerosol spray propellant and aerating agent for canisters of 'whipped' cream.
製造方法
Prepared by thermal decomposition of ammonium nitrate
NH
4NO
3 → N
2O↑ + 2H
2O
調製方法
Nitrous oxide is prepared by heating ammonium nitrate to about
170°C. This reaction also forms water.
一般的な説明
NITROUS OXIDE is a colorless, sweet-tasting gas. NITROUS OXIDE is also known as "laughing gas". Continued breathing of the vapors may impair the decision making process. NITROUS OXIDE is noncombustible but NITROUS OXIDE will accelerate the burning of combustible material in a fire. NITROUS OXIDE is soluble in water. Its vapors are heavier than air. Exposure of the container to prolonged heat or fire can cause NITROUS OXIDE to rupture violently and rocket. NITROUS OXIDE is used as an anesthetic, in pressure packaging, and to manufacture other chemicals.
反応プロフィール
NITROUS OXIDE is an oxidizing agent. Nonflammable but supports combustion. Can explode at high temperature (after vaporization). Vapors can undergo a violent reaction with aluminum, boron, hydrazine, lithium hydride, phenyllithium, phosphine, sodium, tungsten carbide [Bretherick, 5th ed., 1995, p. 1686]. Contact of the cold liquefied gas with water may result in vigorous or violent boiling. If the water is hot, a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquefied gas contacts water in a closed container [Handling Chemicals Safely 1980].
危険性
Supports combustion, can form explosive
mixture with air. Narcotic in high concentration.
Central nervous system impairment, hematologic
effects, and embryo/fetal damage. Questionable
carcinogen.
健康ハザード
Toxicity and irritant effects of nitrous oxidein humans are very low. It is an anesthetic.Inhalation of this gas at high concentrationscan produce depression of the central nervous system, decrease in body temperature,and fall in blood pressure. The LC50 valueof a 4-hour exposure in mice is in the rangeof 600 ppm.
火災危険
Behavior in Fire: Will support combustion, and may increase intensity of fire. Containers may explode when heated.
使用用途
亜酸化窒素は、歯科及び外科、産婦人科の麻酔に多く用いられます。半導体用材料や原子吸光分析用キャリアガスなど工業用にも使用されるほか、漏えい検知、冷媒、風船やタイヤへのガス充填にも使われます。
スペインの有名レストランがソーダサイフォンを使って食品に亜酸化窒素ガスを添加し、空気のように軽い泡の料理を開発しました。亜酸化窒素ガスを食品添加物扱いとし、液状の食材に亜酸化窒素を混ぜてムース状にする料理法をエスプーマと呼びます。日本でも流行した料理法です。
また、亜酸化窒素ガスは大気よりも酸素の存在比率が大きく、熱分解した時に大気よりも酸素分圧の高い混合気体が得られます。そのため、レース車のエンジンなどの内燃機関のブースト用に用いられる場合もあります。
材料の用途
Nitrous oxide is noncorrosive and may therefore
be used with any of the common, commercially
available metals. Because of its oxidizing action, however, all equipment being prepared to
handle nitrous oxide, particularly at high pressures, must be free of oil, grease, and other
readily combustible materials. Nitrous oxide
may cause swelling ofsome elastomers.
臨床応用
The low potency of nitrous oxide (MAC＝ 104%) precludes it from being used alone for surgical anesthesia.To use it as the sole anesthetic agent the patient wouldhave to breathe in pure N
2Oto the exclusion of oxygen. Thissituation would obviously cause hypoxia and potentially leadto death. Nitrous oxide can inactivate methionine synthase, aB12-dependent enzyme necessary for the synthesis of DNAand therefore should be used with caution in pregnant andB12-deficient patients. Nitrous oxide is also soluble in closedgas containing body spaces and can cause these spaces toenlarge when administered possibly leading to adverse occurrences(occluded middle ear, bowel distension, pneumothorax).Nitrous oxide is a popular anesthetic in dentistrywere it is commonly referred to as “laughing gas.” It is usedin combination with more potent anesthetics for surgicalanesthesia and remains a drug of recreational abuse.Nitrous oxide undergoes little or no metabolism.
安全性プロファイル
Moderately toxic by
inhalation. Human systemic effects by
inhalation: general anesthetic, decreased
pulse rate without blood pressure fall, and
body temperature decrease. An experimental
teratogen. Experimental reproductive
effects. Mutation data reported. An
asphyxiant. Does not burn but is flammable
by chemical reaction and supports
combustion. Moderate explosion hazard; it
can form an explosive mixture with air.
Violent reaction with Al, B, hydrazine, LiH,
LiC6H5, PH3, Na, tungsten carbide. Also
self-explodes at high temperatures.
安全性
Nitrous oxide is most commonly used therapeutically as an
anesthetic and analgesic. Reports of adverse reactions to nitrous
oxide therefore generally concern its therapeutic use, where
relatively large quantities of the gas may be inhaled, rather than
its use as an excipient.
The main complications associated with nitrous oxide inhalation
occur as a result of hypoxia. Prolonged administration may also be
harmful. Nitrous oxide is rapidly absorbed on inhalation.
職業ばく露
Used as an anesthetic in dentistry and
surgery; used as a gas in food aerosols, such as whipped
cream; used in manufacture of nitrites; used in rocket fuels;
in firefighting; diesel emissions. Large amounts of nitrous
oxide will decrease the amount of available oxygen.
Nitrous Oxide 2231
Oxygen should be routinely tested to ensure that it is at
least 19% by volume.
概要
亜酸化窒素とは、組成式N2Oで表される常温で気体の窒素酸化物の一種です。
別名として、次亜硝酸無水物、笑気ガス、酸化二窒素、一酸化二窒素もあります。
発がん性
The possible carcinogenicity of nitrous
oxide has been studied in dentists and chairside
assistants with occupational exposures. No
effect was observed in male dentists, but a 2.4-
fold increase in cancer of the cervix in heavily
exposed female assistants was reported.7 Other
epidemiological reports of workers exposed to
waste anesthetic gases have been negative.1
Carcinogenic bioassays in animals have yielded
negative results. Nitrous oxide was not genotoxic
in a variety of assays.
製造方法
亜酸化窒素の工業的な製造方法としては、の熱分解法、アンモニア酸化法、法の3通りがあります。
1. 硝酸アンモニウムの熱分解法
硝酸アンモニウム熱分解法は、約250℃に保持した反応槽に原料の80%硝酸アンモニウム水溶液を、一定流量で滴下しながら分解させて亜酸化窒素を得る方法です。反応によって得られたガスは亜酸化窒素純度97~98%であり、不純物として、窒素、アンモニア、酸化窒素、を含みます。
この粗製亜酸化窒素ガスから水を冷却器で凝縮留去後、強アルカリ水溶液、強酸で洗浄することにより、不純物が除去された精製亜酸化窒素が得られます。
2. アンモニア直接酸化法
アンモニア直接酸化法はアンモニアを触媒により酸化して亜酸化窒素を得る方法です。反応生成物中の亜酸化窒素濃度が低いことと、触媒の寿命が短いことがプロセス上の課題でしたが、触媒の改良により現在は工業化されています。
不純物を含む粗製亜酸化窒素ガスを加圧下で水に吸収させ、減圧下で水より放散させることにより、酸素、窒素を分離して高純度の亜酸化窒素を得ます。
3. スルファミン酸法
スルファミン酸法はスルファミン酸と硝酸を80~100℃で反応させて亜酸化窒素を得る方法です。
NH2SO3H + HNO3 → N2O + H2SO4 + H2O
貯蔵
Nitrous oxide is essentially nonreactive and stable except at high
temperatures; at a temperature greater than 500°C nitrous oxide
decomposes to nitrogen and oxygen. Explosive mixtures may be
formed with other gases such as ammonia, hydrogen, and other
fuels. Nitrous oxide should be stored in a tightly sealed metal
cylinder in a cool, dry place.
輸送方法
UN1070 Nitrous oxide, compressed, Hazard
Class: 2.2; Labels: 2.2-Nonflammable compressed gas;
5.1-Oxidizer; UN2201 Nitrous oxide, refrigerated 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
Wash the gas with concentrated alkaline pyrogallol solution, to remove O2, CO2, and NO2, then dry it by passing it through columns of P2O5 or Drierite, and collecting in a dry trap cooled in liquid N2. It is further purified by freeze-pump-thaw and distillation cycles under vacuum [Ryan & Freeman J Phys Chem 81 1455 1977, Schenk in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I pp 484-485 1963].
不和合性
Nitrous oxide is a weak oxidizer.
Incompatible with oxidizers (chlorates, nitrates, peroxides,
permanganates, perchlorates, chlorine, bromine, fluorine,
etc.); contact may cause fires or explosions. Keep away
from alkaline materials, strong bases, strong acids, oxoacids,
epoxides. Violent reactions with organic peroxides,
hydrazine, hydrogen, hydrogen sulfide; lithium, boron, lithium
hydride, sodium, aluminum, phosphine. This chemical
is a strong oxidizer @ .300C and self-explodes at high
temperature. May form explosive mixtures with ammonia,
carbon monoxide; hydrogen sulfide; oil, grease and fuels.
廃棄物の処理
Disperse in atmosphere or
spray on dry soda ash/lime with great care; then flush to
sewer.
規制状況(Regulatory Status)
GRAS listed. Accepted for use as a food additive in Europe.
Included in nonparenteral medicines licensed in the UK and USA.
Included in the Canadian List of Acceptable Non-medicinal
Ingredients.
酸化二窒素 上流と下流の製品情報
原材料
準備製品