ジクロロジフルオロメタン 化学特性,用途語,生産方法
解説
[別用語参照]クロロフルオロメタン
森北出版「化学辞典（第2版）
用途
冷凍機用冷媒、エアゾール噴射剤、ウレタン、ポリエチレン、ポリスチレン等のフォームの発泡剤。気密検査のトレーサー、半導体ドライエッチング
効能
噴霧剤
説明
Dichlorodifluoromethane is known as CFC-12, also called R-12, or Freon-12. R-12 is a general name for Refrigerant-12. Freon is a trade name for DuPont. CFC stands for chlorofl uorocarbons, which are nontoxic, nonfl ammable, synthetic chemicals containing atoms of carbon, chlorine, and fluorine.CFC use climbed steadily worldwide as it was incorporated in refrigeration and air conditioning, as well as being used as propellants, blowing agents, and solvents.
dichlorodifluoromethane structure
化学的特性
Dichlorodifluoromethane is a liquefied gas and exists as a liquid at room temperature when contained under its own vapor pressure, or as a gas when exposed to room temperature and atmospheric pressure. The liquid is practically odorless and colorless. The gas in high concentrations has a faint etherlike odor. Dichlorodifluoromethane is noncorrosive, nonirritating, and nonflammable. Ethereal odor at .20% by volume. Shipped as a compressed gas.
Dichlorotetrafluoroethane is a colorless, nonflammable liquefied gas with a faint, ethereal odor.
Trichloromonofluoromethane is a clear, volatile liquid at room temperature and atmospheric pressure. It has a characteristic carbon tetrachloride-like odor and is nonirritating and nonflammable.
来歴
CFCs were developed in the 1930s as coolants for refrigerator, freezer,
and motor vehicle air conditioners.they subsequently found use as metal cleaners, degreasers,
propellants, solvents, and blowing agents in the production of foams. CFCs have received
widespread environmental attention because of their potential to deplete stratospheric ozone.
使用
Refrigerant, aerosol propellant.
Dichlorodifluoromethane is used as a refrigerant gas in refrigerators and air conditioners.
Dichlorodifluoromethane is also used in aerosol sprays, in plastics, and as an aid in detecting leaks.
Dichlorodifluoromethane harms the ozone layer, which protects the earth from the sun’s ultraviolet radiation.
調製方法
Dichlorodifluoromethane is prepared by the reaction of hydrogen
fluoride with carbon tetrachloride in the presence of a suitable
catalyst, such as polyvalent antimony. The dichlorodifluoromethane
formed is further purified to remove all traces of water
and hydrochloric acid as well as traces of the starting and
intermediate materials.
Trichloromonofluoromethane is also obtained by this process.
Dichlorotetrafluoroethane is prepared by the reaction of
hydrogen fluoride with chlorine and perchloroethylene in the
presence of a suitable catalyst such as polyvalent antimony.
一般的な説明
A colorless gas having a faint ethereal odor. Shipped as a liquid confined under its own vapor pressure. Contact with the unconfined liquid can cause frostbite. Both components are noncombustible. Can asphyxiate by the displacement of air. Exposure of the closed container to prolonged heat or fire can cause Dichlorodifluoromethane to rupture violently and rocket.
空気と水の反応
The liquefied gas poured into water can be violently explosive. This is due to the phase transition from superheated liquid to vapor.
反応プロフィール
The reaction of aluminum with various halogenated hydrocarbons produces a self-sustaining reaction with sufficient heat to melt aluminum pieces, examples of other halogenated hydrocarbons are fluorotrichloromethane, Dichlorodifluoromethane, chlorodifluoromethane, tetrafluoromethane. The vigor of the reaction appears to be dependent on the combined degree of fluorination and the vapor pressure, [Chem. Eng. News 39(27):44(1961)].
健康ハザード
INHALATION: some narcosis when 10% in air is breathed.
安全性プロファイル
Dichlorodifluoromethane is a colorless, non-flammable gas that can affect you when breathed in. Acute (short-term) exposure to dichlorodifluoromethane can cause dizziness, lightheadedness, and trouble with concentration. Exposure to high concentrations of the gas can cause the heart to beat irregularly or to stop. The health effects of chronic (long-term) exposure to dichlorodifluoromethane are unknown at this time. There is no evidence of an increase in cancer risk due to exposure to dichlorodifluoromethane.
職業ばく露
Dichlorodifluoromethane is used as an
aerosol propellant, refrigerant and foaming agent
発がん性
There was no evidence of carcinogenicity
when groups of 50 male and 50 female rats were
given oral doses of 15 or 150 mg/kg of CFC 12 daily for
2 years. As described above, there was no evidence
of carcinogenicity when groups of 90 male and 90 female
rats and of 60 male and 60 female mice were exposed by
inhalation to levels of 1000 and 5000 ppm, 4 h/day, 5 days/
week.
環境運命予測
Surface Water. Estimated half-lives of dichlorodifluoromethane from an experimental marine
mesocosm during the spring (8–16 °C) and winter (3–7 °C) were 20 and 13 d, respectively
(Wakeham et al., 1983).
貯蔵
Chlorofluorocarbon propellants are nonreactive and stable at
temperatures up to 5508℃. The liquefied gas is stable when used
as a propellant and should be stored in a metal cylinder in a cool,
dry place.
輸送方法
UN1028 Dichlorodifluoromethane or Refrigerant
gas R-12, Hazard class: 2.2; Labels: 2.2-Nonflammable
compressed 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
純化方法
Pass the gas through saturated aqueous KOH then conc H2SO4, and a tower packed with activated copper on Kielselguhr at 200o removed CO2 and O2. A trap cooled to -29o removed a trace of high boiling material. It is a non-flammable propellant.
不和合性
The presence of greater than 5% water in solutions that contain
trichloromonofluoromethane may lead to hydrolysis of the
propellant and the formation of traces of hydrochloric acid, which
may be irritant to the skin or cause corrosion of metallic canisters.
Trichloromonofluoromethane may also react with aluminum, in the
presence of ethanol, to cause corrosion within a cylinder with the
formation of hydrogen gas. Similarly, alcohols in the presence of
trace amounts of oxygen, peroxides, or other free-radical catalysts
may react with trichloromonofluoromethane to form trace quantities
of hydrochloric acid.
Both dichlorodifluoromethane and dichlorotetrafluoroethane
are compatible with most ingredients used in pharmaceutical
aerosols. Because of their poor miscibility with water, most MDIs
are formulated as suspensions. However, solution MDIs can be
prepared through the use of ethanol as a cosolvent for water and
propellant, resulting in a clear solution (provided the water content
is less than 5%).
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. Because of potential
ozone decomposition in the stratosphere, R-12 should be
released to the atmosphere only as a last resort.
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste
containing this contaminant (≥100 kg/mo) must conform
with EPA regulations governing storage, transportation,
treatment, and waste disposal
規制状況(Regulatory Status)
Included in the FDA Inactive Ingredients Database (aerosol
formulations for inhalation, nasal, oral, and topical applications).
With few exceptions for existing MDIs, the FDA and EPA have
banned the use of CFCs in the USA after 31st December 2008, with
all CFCs to be phased out by 2010–2015. Included in nonparenteral
medicines licensed in the UK.
ジクロロジフルオロメタン 上流と下流の製品情報
原材料
準備製品