Ethylen Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
FARBLOSES KOMPRIMIERTES GAS MIT CHARAKTERISTISCHEM GERUCH.
PHYSIKALISCHE GEFAHREN
Das Gas ist leichter als Luft. Fließen, Schütten o.ä. kann zu elektrostatischer Aufladung führen.
CHEMISCHE GEFAHREN
Kann polymerisieren unter Bildung aromatischer Verbindungen unter Einfluss von Temperaturen über 600°C. Reagiert mit starken Oxidationsmitteln unter Feuer- und Explosionsgefahr.
ARBEITSPLATZGRENZWERTE
TLV: 200 ppm (als TWA); Krebskategorie A4 (nicht klassifizierbar als krebserzeugend für den Menschen); (ACGIH 2005).
MAK: Krebserzeugend Kategorie 3B; (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation.
INHALATIONSGEFAHREN
Beim Entweichen aus dem Behälter kann das Gas die Luft verdrängen. Erstickungsgefahr in geschlossenen Räumen.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Exposition kann Bewusstseinstrübung verursachen.
LECKAGE
Gefahrenbereich verlassen! Belüftung. Zündquellen entfernen und Gaszufuhr unterbrechen, wenn möglich. Persönliche Schutzausrüstung: Chemikalienschutzanzug mit umgebungsluftunabhängigem Atemschutzgerät.
R-Sätze Betriebsanweisung:
R12:Hochentzündlich.
R67:Dämpfe können Schläfrigkeit und Benommenheit verursachen.
S-Sätze Betriebsanweisung:
S9:Behälter an einem gut gelüfteten Ort aufbewahren.
S16:Von Zündquellen fernhalten - Nicht rauchen.
S33:Maßnahmen gegen elektrostatische Aufladungen treffen.
S46:Bei Verschlucken sofort ärztlichen Rat einholen und Verpackung oder Etikett vorzeigen.
Beschreibung
Ethylene is a colorless, odorless gas that is the simplest alkene hydrocarbon. It is a natural plant
hormone and is produced synthetically from natural gas and petroleum. The double bond in
ethylene makes this compound highly reactive, and the volume of ethylene used in the chemical
industry is greater than any other organic compound.
Chemische Eigenschaften
Ethylene, an alkene is a colorless gas (at room
temperature). Sweet odor. Minimum detectable odor 5
260 ppm.
Verwenden
Oxyethylene welding and cutting metals; manufacture of alcohol, mustard gas, and many other organics. manufacture of ethylene oxide (for plastics), "Polythene", polystyrene and other plastics. Plant growth regulator; used commercially to accelerate the ripening of various fruits.
Definition
ethylene: A colourlessflammable gaseous hydrocarbon,C
2H
4; m.p. –169°C; b.p. –103.7°C. It isthe first member of the alkene seriesof hydrocarbons. It is made bycracking hydrocarbons from petroleumand is now a major raw materialfor making other organicchemicals (e.g. ethanal, ethanol,ethane-1,2-diol). It can be polymerizedto polyethene. It occurs naturallyin plants, in which it acts as agrowth substance promoting theripening of fruits.
Vorbereitung Methode
Ethylene is primarily obtained from the ethane and propane components of natural gas andfrom the naphtha, kerosene, and gas oil components of crude oil. It can also be synthesizedthrough the dehydration of ethanol (C
2H
5OH). The production of ethylene from hydrocarbonfeedstocks involves mixing with steam and then subjecting the hydrocarbons to thermalor catalytic cracking. Cracking is a process in which organic molecules are broken down intosmaller molecules. Thermal cracking involves the use of heat and pressure. Catalytic crackinguses various catalysts to reduce the amount of heat and pressure required in the process.Th ermal cracking of hydrocarbons to ethylene occurs between approximately 650°C and800°C (1200°F and 1500°F). After hydrocarbons are cracked, a mixture containing ethyleneand other gases such as methane, ethane, and propane is obtained. Ethylene is separated fromthese through physical processes such as fractional distillation, refrigeration, absorption, oradsorption.
Reaktionen
Ethylene reacts: (1) with the halogens to form substitution halides; (2) with hypochlorous and hypobromous acid to form ethylene chlorohydrin or ethylene bromohydrin, respectively; (3) with hydrogen iodide or bromide (not chloride) to form ethyl iodide or ethyl bromide; (4) with hydrogen, in the presence of a catalyst, e.g., finely divided nickel at 150 °C, to form ethane; (5) with concentrated sulfuric acid at 160 °C to form ethyl hydrogen sulfate; and (6) with potassium permanganate to form ethylene glycol, although glycol is preferably made from ethylene dichloride or chlorohydrin.
Allgemeine Beschreibung
A colorless gas with a sweet odor and taste. ETHYLENE is lighter than air. ETHYLENE is easily ignited and a flame can easily flash back to the source of the leak. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. Can cause explosion.
Air & Water Reaktionen
Highly flammable.
Reaktivität anzeigen
Peroxidizable monomer may initiate exothermic polymerization of the bulk material [Bretherick 1979. p. 160]. ETHYLENE in the presence of aluminum chloride may undergo a violent reaction [J. Inst. Pet. 33:254. 1947]. Ozone and ETHYLENE react explosively [Berichte 38:3837]. ETHYLENE can polymerize at low pressure if catalyzed by titanium halides. (Sundaram, K. M, M. M. Shreehan, E. F. Olszewski. thylene. Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 2001.)
Hazard
Highly flammable, dangerous fire and
explosion risk; explosive limits in air 3–36% by
volume. Simple asphyxiant; questionable carcinogen.
Health Hazard
Exposure to ethylene atmosphere can causeasphyxiation. At high concentrations it is anarcotic and can cause unconsciousness.
Brandgefahr
Flammable gas; burns with a luminous flame;
autoignition temperature 490°C (914°F)
(NFPA 1997), 543°C (1009°F) (Merck
1996); fire-extinguishing measure: shut off
the flow of gas; use a water spray to keep
fire-exposed containers cool.
Ethylene forms explosive mixtures in
air; the LEL and UEL values are 2.7%
and 36% by volume of air, respectively.
Its reaction with fluorine is explosively
violent (△H=- 112 kcal/mol), and violent
with chlorine (△H=- 36 kcal/mol). In the
presence of sunlight or UV light, an ethylene–
chlorine mixture will explode spontaneously.
The reaction is explosive at room
temperature over the oxides of mercury or
silver (Mellor 1946, Suppl. 1956). Ethylene
reacts vigorously with oxidizing substances.
It reacts with ozone to form ethylene
ozonide, H2C(O3)CH2, which is unstable
and explodes on mechanical shock. Acidcatalyzed
addition of hydrogen peroxide
may produce ethyl hydroperoxide, which is
unstable and explodes on heat or shock:.
Materials Uses
Installations must be designed to withstand the
pressures involved and must comply with all
applicable regulations. Because it is noncorrosive,
any common commercially available metals
may be used with ethylene.
Sicherheitsprofil
Suspected carcinogen.
A simple asphyxiant. High concentrations
cause anesthesia. A common air
contaminant. It is phytotoxic. A very
dangerous fire hazard when exposed to heat
or flame. Moderate explosion hazard when
exposed to flame. A flammable gas. To figh fire, stop flow of gas, use Co2, dry chemical,
or fine water spray. Mixtures with aluminum
chloride explode in the presence of nickel
catalysts, methyl chloride, or nitromethane.
Explosive reaction with
bromotrichloromethane (at 120℃/51 bar),
carbon tetrachloride (25-100°C/30 bar).
Explosive reaction with chlorine catalyzed
by sunlight or UV light or in the presence of
mercury(I) oxide, mercury(Ⅱ) oxide, or
silver oxide. Mixtures with
chlorotrifluoroethylene polymerize
explosively when exposed to 50 kV gamma
rays at 308 krad/hr. Has been involved in
industrial accidents. Violent polymerization
is catalyzed by copper above 4OO0C/54 bar.
Incompatible with AlCl3, (CC4 + benzoyl
peroxide), (bromotrichloromethane +
NCh), 03, CCl4, Cl2, NOx,
tetrafluoroethylene trifluorohypofluorite.
When heated to decomposition it emits
acrid smoke and irritating fumes
mögliche Exposition
Ethylene is used in production of fabricated plastics, antifreeze; making fibers; to manufacture ethylene oxide, polyethylene for plastics, alcohol, mustard gas and
other organics. It is used to accelerate ripening of fruit; as an
anesthetic; and for oxyethylene welding and cutting of metals
Carcinogenicity
A case-control study of brain
cancer among Texas petrochemical workers reported
increased risks associated with exposure to multiple chemicals,
including ethene. The findings were not
statistically significant. The risks for ethene have not been
shown to increase with increasing duration of employment. The observed increases could not be attributed to specific
chemical exposures.
Environmental Fate
Emitted ethene is distributed primarily into the atmosphere
and reacts with photochemically reactive hydroxyl radicals,
ozone, and nitrate radicals, with half-lives ranging from 1.9,
6.5, and 190 days, respectively. Biodegradation in water occurs
with half-lives in the range of 1–28 days, or under anaerobic
conditions, 3–112 days. Bioaccumulation in aquatic organisms
is not expected to occur, based on ethene’s high vapor pressure
and log octanol/water partition coefficient.
Lager
Ethylene is stored in a cool, well-ventilatedarea isolated from oxygen, chlorine, andflammable and oxidizing substances. It isprotected against lightning, statical electricity,heat, and physical damage. It is shippedin steel pressure cylinders and tank barges.
Versand/Shipping
UN1962 Ethylene, Hazard Class: 2.1; Labels:
2.1-Flammable gas; UN1038 Ethylene, refrigerated liquid
(cryogenic liquid), 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.
läuterung methode
Purify ethylene by passage through a series of towers containing molecular sieves or anhydrous CaSO4 or a cuprous ammonia solution, then conc H2SO4, followed by KOH pellets. Alternatively, it has been condensed in liquid nitrogen, with melting, freezing and pumping to remove air before passage through an activated charcoal trap, followed by a further condensation in liquid air. A sputtered sodium trap was used to remove oxygen. [Beilstein 1 IV 677.]
Inkompatibilitäten
A highly flammable gas at room temperature. Contact with oxidizers may cause explosive polymerization and fire. May be spontaneously explosive in
sunlight or ultraviolet light when mixed with chlorine.
Reacts violently with mixtures of carbon tetrachloride and
benzoyl peroxide; bromotrichloromethane; aluminum chloride and ozone. Incompatible with acids, halogens, nitrogen
oxides; hydrogen bromide; aluminum chloride; chlorine
dioxide; nitrogen dioxide. May accumulate static electrical
charges, and may cause ignition of its vapors.
Waste disposal
Return refillable compressed
gas cylinders to supplier
Ethylen Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
