Dichlordifluormethan Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
FARBLOSES KOMPRIMIERTES FLüSSIGGAS MIT CHARAKTERISTISCHEM GERUCH.
PHYSIKALISCHE GEFAHREN
Das Gas ist schwerer als Luft. Es kann sich in tiefer gelegenen Bereichen sammeln und den Luftsauerstoff verdrängen.
CHEMISCHE GEFAHREN
Bei Kontakt mit heißen Gegenständen oder Flammen Zersetzung unter Bildung giftiger und ätzender Gase (Chlorwasserstoff ICSC 0163, Phosgen ICSC 0007, Fluorwasserstoff ICSC 0283, Carbonylfluorid ICSC 0633). Reagiert heftig mit Metallenwie Zinkund pulverförmigem Aluminium. Greift Magnesium und seine Legierungen an.
ARBEITSPLATZGRENZWERTE
TLV: () 1000 ppm (als TWA); Krebskategorie A4 (nicht klassifizierbar als krebserzeugend für den Menschen); (ACGIH 2005).
MAK: 1000 ppm, 5000 mg/m? Spitzenbegrenzung: überschreitungsfaktor II(2) Schwangerschaft: Gruppe C; (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation.
INHALATIONSGEFAHREN
Beim Entweichen aus dem Behälter verdampft die Flüssigkeit sehr schnell, wobei die Luft verdrängt wird. Ernste Erstickungsgefahr in geschlossenen Räumen.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Schnelle Verdampfung kann zu Erfrierungen führen. Möglich sind Auswirkungen auf Herz-Kreislaufsystem und Zentralnervensystem mit nachfolgenden Herzfunktionsstörungenund Depression des Zentralnervensystems. Exposition kann Bewusstseinstrübung verursachen (s. Anm.).
LECKAGE
Belüftung.
R-Sätze Betriebsanweisung:
R20:Gesundheitsschädlich beim Einatmen.
R59:Gefährlich für die Ozonschicht.
R23/25:Giftig beim Einatmen und Verschlucken.
R11:Leichtentzündlich.
R39/23/24/25:Giftig: ernste Gefahr irreversiblen Schadens durch Einatmen, Berührung mit der Haut und durch Verschlucken.
R23/24/25:Giftig beim Einatmen, Verschlucken und Berührung mit der Haut.
S-Sätze Betriebsanweisung:
S23:Gas/Rauch/Dampf/Aerosol nicht einatmen(geeignete Bezeichnung(en) vom Hersteller anzugeben).
S24/25:Berührung mit den Augen und der Haut vermeiden.
S59:Informationen zur Wiederverwendung/Wiederverwertung beim Hersteller/Lieferanten erfragen.
S61:Freisetzung in die Umwelt vermeiden. Besondere Anweisungen einholen/Sicherheitsdatenblatt zu Rate ziehen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
S24:Berührung mit der Haut vermeiden.
S16:Von Zündquellen fernhalten - Nicht rauchen.
S7:Behälter dicht geschlossen halten.
S36/37:Bei der Arbeit geeignete Schutzhandschuhe und Schutzkleidung tragen.
Beschreibung
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
Chemische Eigenschaften
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.
History
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.
Verwenden
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.
Vorbereitung Methode
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.
Allgemeine Beschreibung
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.
Air & Water Reaktionen
The liquefied gas poured into water can be violently explosive. This is due to the phase transition from superheated liquid to vapor.
Reaktivität anzeigen
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)].
Health Hazard
INHALATION: some narcosis when 10% in air is breathed.
Sicherheitsprofil
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.
mögliche Exposition
Dichlorodifluoromethane is used as an
aerosol propellant, refrigerant and foaming agent
Carcinogenicity
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.
Environmental Fate
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).
Lager
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.
Versand/Shipping
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
läuterung methode
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.
Inkompatibilitäten
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%).
Waste disposal
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
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.
Dichlordifluormethan Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
