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外観
無色～ほとんど無色透明液体
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性質
クロロエタンの融点は−139°Cで、沸点は12.3°Cです。
常温常圧でエーテル臭のある気体です。
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反応
図2. クロロエタンの反応
クロロエタンが鉛-ナトリウム合金と反応すると、テトラエチル鉛が合成できます。テトラエチル鉛は、エンジンのノッキングを防ぐためのアンチノック剤に使用可能です。類縁体のテトラメチル鉛、ジエチルジメチル鉛、エチルトリメチル鉛と合わせて、四アルキル鉛やアルキル鉛と呼ばれています。
テトラエチル鉛は揮発しやすく、特異臭を持つ無色の液体です。日光に不安定で、少しずつ分解します。引火性があり、金属に腐食性を有します。蒸気として皮膚から吸収されやすく、神経毒性が強いです。
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解説
クロロエタン,融点－138.3 ℃，沸点12.3 ℃．d40"0.9214．エタノールやエーテルに可溶．有機合成のエチル化剤，冷媒，殺虫剤，あるいは麻酔剤などにも使われる場合もある．
森北出版「化学辞典（第2版）
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用途
エチルセルロース合成原料、ポリスチレン発泡助剤、オレフィン重合触媒原料、有機金属化合物原料、エチル化剤、農薬中間体 (NITE初期リスク評価書)
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構造
クロロエタンの示性式はCH3CH2Clと表されます。
モル質量は64.51で、密度は0.92です。
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製造
常温，常圧では気体であるが，加圧，冷却により容易に液化するクロロエタン．
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合成法
図1. クロロエタンの合成
クロロエタンは、1440年に初めてバジル・バレンタイン (英: Basil Valentine) によって、エタノールと塩酸の反応で合成されました。1648年にはエタノールと塩化亜鉛の反応でも生成しています。
光源下でによりの水素原子1個を塩素原子で置換して、クロロエタンを合成可能です。塩化水素とエタノールからもクロロエタンが得られますが、経済性で劣ります。さらに、130〜250°Cで塩化アルミニウム触媒を用いて、3気圧でに塩化水素を付加しても、クロロエタンを製造可能です。
またクロロエタンは、ポリ塩化ビニルの製造で副生物として生じます。クロロエタンの需要が少なくなった現在では、この副生成がクロロエタンの主な製造法でもあります。
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効能
表面麻酔薬
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危険性
クロロエタンは、クロロエタン類の中では最も毒性が低いです。ただし他の有機塩素化合物と同様に、中枢神経系を抑制します。空気中の濃度が 1%未満のクロロエタン蒸気を吸い込んでも、通常は症状がありません。通常3〜5%の濃度で被害者には、アルコール中毒に似た症状が出ます。濃度が15%以上の蒸気を吸い込むと、致命的になる可能性が高いです。
6〜8%以上の濃度に晒されると、被害者は呼吸が浅くなり、意識を失って、心拍数が低下します。意識を回復するために、暴露領域からの移動が推奨されています。4時間以上の暴露では、二日酔いに似た副作用を引き起こし、例えば脱水、めまい、明確な視力の喪失、一時的な意識の喪失などです。水分、ビタミン、砂糖などの摂取によって、犠牲者が通常の健康状態に戻りやすくなります。
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化学的特性
colourless gas
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物理的性質
Clear, colorless gas or liquid with a pungent or faint, sweetish ether-like odor. When spilled, ethyl
chloride evaporates quickly. Odor threshold concentration is 4.2 ppm (quoted, Amoore and
Hautala, 1983).
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使用
Chloroethane is a useful reactant in organic synthesis.
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適応症
Chlorethane (ethyl chloride) is a highly flammable liquid that acts as a topical vapocoolant
to control pain associated with minor surgical procedures.When applied as
a spray, the product produces freezing of superficial tissues to ?20?C, which results
in insensitivity of peripheral nerve endings and local anesthesia that is maintained
up to 1 minute. Other coolant sprays can be used with the same effect.
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調製方法
Ethyl Chloride can be synthesized by treatment of ethyl alcohol with HCl, cleavage of diethylether with HCl in the presence of a catalyst (ZnCl2), chlorination of ethane or hydrochlorination of ethylene. The latter is the choice of industry. The reaction is carried out at 125 °F and 125 psi in the presence of AlCl3, which is dissolved in ethyl chloride.
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定義
A highly reactive manmade volatile organic com-
pound that is highly reactive in the atmosphere. It
readily reacts with oxidizing agents to release the
chlorine atoms which, circulate and cause tropo-
spheric ozone to decompose.
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一般的な説明
A clear colorless gas with a pungent odor. Flash point -58°F. Boiling point 54°F. Less dense than water and insoluble in water. Vapors are heavier than air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket.Ethyl chloride is used as a solvent for oils,resins,and waxes. It is used in medicine and as an intermediate in synthesis.
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空気と水の反応
Highly flammable. Insoluble in water.
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反応プロフィール
CHLOROETHANE is heat sensitive. CHLOROETHANE will hydrolyze in the presence of alkalis and water. CHLOROETHANE reacts with water or steam to produce toxic and corrosive fumes. CHLOROETHANE can also react vigorously with oxidizing materials. The vapor forms highly flammable mixtures with air. A mixture of CHLOROETHANE with potassium is shock-sensitive. Contact with chemically active metals such as Na, K, Ca, powdered Al, Zn and Mg may result in violent reactions.
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危険性
Highly flammable, severe fire and explosion risk; flammable limits in air 3.8–15.4%. Irritant
to eyes. Questionable carcinogen.
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健康ハザード
Vapor causes drunkenness, anesthesia, possible lung injury. Liquid may cause frostbite on eyes and skin.
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使用用途
20世紀終わりまで、クロロエタンの主な用途はテトラエチル鉛 (Pb(C2H5)4) の原料でした。テトラエチル鉛はかつて燃焼不良防止剤としてガソリンに加えられましたが、大気汚染やその毒性から徐々に用いられなくなり、クロロエタンの需要は極端に落ち込んでいます。
以前にクロロエタンは、他のハロゲン化アルキルのように、冷媒、麻酔薬、エアロゾルの噴霧剤、発泡スチロールの発泡剤として用いられていました。
現在は工業的に、セルロースからエチルセルロース (エトセル) を合成するための原料に使用されています。エチルセルロースは塗料の増粘剤や結着剤 (バインダー) 、化粧品などの成分として使用可能です。
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化学反応性
Reactivity with Water: No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
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安全性プロファイル
Suspected carcinogen
with experimental carcinogenic and
neoplastigenic data. Mildly toxic by
inhalation. An irritant to sh, eyes, and mucous membranes. The liquid is harmful
to the eyes and can cause some irritation. In
the case of guinea pigs, the symptoms
attending exposure are similar to those
caused by methyl chloride, except that the
signs of lung irritation are not as
pronounced. It gives some warning of its
presence because it is irritating, but it is
possible to tolerate exposure to it until one
becomes unconscious. It is the least toxic
of all the chlorinated hydrocarbons. It can
cause narcosis, although the effects are
usually transient.
A very dangerous fire hazard when
exposed to heat or flame; can react
vigorously with oxidizing materials. Severe
explosion hazard when exposed to flame.
Reacts with water or steam to produce toxic
and corrosive fumes. Incompatible with
potassium. To fight fire, use carbon dioxide.
When heated to decomposition it emits
toxic fumes of phosgene and Cl-. See also
CHLORINATED HYDROCARBONS,
ALIPHATIC.
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職業ばく露
Ethyl chloride is used as an ethylating
agent in the manufacture of tetraethyl lead, dyes, drugs,
and ethyl cellulose; as a pharmaceutical, solvent; alkylating
agent; as a refrigerant and as a local anesthetic (freezing).
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発がん性
The EPA has not made a
carcinogenicity assessment as yet. However, the State of
California reviewed the carcinogenicity information.
CalEPA, using the NTP study, developed a cancer
potency estimate of 4.7E-3 per mg/kg/day and defined a No
Significance Risk Level (NSRL) of 1 50 μg/day.
Increased cancer of the uterus of female mice has been
produced by exposure to 15,000 ppm, but lower concentrations
have not been studied. Rats and mice were exposed to 0
or 15,000 ppm of ethyl chloride in an NTP 2-year study with
mixed results. Results in male rats were considered
equivocal based on a combined total of five skin tumors
versus none in the control male rats. Likewise, female rats’
results were considered equivocal because three astrocytomas
were found versus none in the female control rats. The
male mouse group had such poor survival that it was deemed
an inadequate study although combined alveolar/bronchiolar
adenomas and carcinomas were reported (10/48 versus 5/50
in the control male rats). Female mice exposed to 15,000 ppm
had clear evidence of an effect, for 43/50 mice had endometrial
uterine carcinomas versus 0/49 in the female control
mice. In addition, there was a suggestion of an increase in
combined hepatocellular adenomas and carcinomas in the
female mice (8/48 exposed versus 3/49 control). There is
clear evidence for carcinogenicity in female B6C3F1 mice
and equivocal evidence in male and female F344/N rats (high
incidence of uterine carcinomas.)
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環境運命予測
Photolytic. The rate constant for the reaction of chloroethane and OH radicals in the atmosphere
at 300 K is 2.3 x 10-11 cm3/molecule?sec (Hendry and Kenley, 1979). At 296 K, a photooxidation
rate constant of 3.9 x 10-13 cm3/molecule?sec was reported (Howard and Evenson, 1976). The
estimated tropospheric lifetime is 14.6 d (Nimitz and Skaggs, 1992).
Chemical/Physical. Under laboratory conditions, chloroethane hydrolyzed to ethanol (Smith and
Dragun, 1984). An estimated hydrolysis half-life in water at 25 °C and pH 7 is 38 d, with ethanol
and HCl being the expected end-products (Mabey and Mill, 1978). Based on a measured
hydrolysis rate constant of 5.1 x 10-7 at 25 °C and pH 7, the half-life is 2.6 yr (Jeffers and Wolfe,
1996).
In air, formyl chloride is the initial photooxidation product (U.S. EPA, 1985). In the presence of
water, formyl chloride hydrolyzes to HCl and carbon monoxide (Morrison and Boyd, 1971).
Burns with a smoky, greenish flame releasing hydrogen chloride (Windholz et al., 1983).
In the laboratory, the evaporation half-life of chloroethane (1 mg/L) from water at 25 °C using a
shallow-pitch propeller stirrer at 200 rpm at an average depth of 6.5 cm was 23.1 min (Dilling,
1977).
At influent concentrations of 1.0, 0.1, and 0.01 mg/L, the GAC adsorption capacities at pH 5.3
were 0.59, 0.07, and 0.007 mg/g, respectively (Dobbs and Cohen, 1980).
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輸送方法
UN1037 Ethyl chloride, Hazard Class: 2.1;
Labels: 2.1-Flammable gas. 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.
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純化方法
Pass ethyl chloride through absorption towers containing, successively, conc H2SO4, NaOH pellets, P2O5 on glass wool, or soda-lime, CaCl2, P2O5. Condensed it into a flask containing CaH2 and fractionally distil it. It has also been purified by illumination in the presence of bromine at 0o using a 1000W lamp, followed by washing, drying and distilling. [Beilstein 1 IV 124.]
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不和合性
Flammable gas. Slow reaction with
water; forms hydrogen chloride gas. Contact with moisture
(water, steam) forms hydrochloric acid and/or fumes of
hydrogen chloride. May accumulate static electrical
charges, and may cause ignition of its vapors. May form
explosive mixture with air. Contact with chemically active
metals: aluminum, lithium, magnesium, sodium, potassium,
zinc may cause fire and explosions. Attacks some plastics
and rubber.
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廃棄物の処理
Return refillable compressed
gas cylinders to supplier. Incineration, preferably after mixing with another combustible fuel. Care must be exercised
to assure complete combustion to prevent the formation of
phosgene. An acid scrubber is necessary to remove the halo
acids produced.
