Diazomethan Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
GELBES GAS.
PHYSIKALISCHE GEFAHREN
Das Gas ist schwerer als Luft und kann sich am Boden ausbreiten. Fernzündung möglich.
CHEMISCHE GEFAHREN
Bei Stoß, Reibung oder Erschütterung explosionsartige Zersetzung möglich. Kann beim Erhitzen auf 100°C, bei Kontakt mit rauhen Oberflächen, wenn Verunreinigungen oder Feststoffe in der unverdünnten Flüssigkeit oder in konzentrierten Lösungen vorhanden sind oder unter starkem Lichteinfluss explodieren. Kontakt mit Alkalimetallen und Calciumsulfat verursacht Explosionen.
ARBEITSPLATZGRENZWERTE
TLV: 0,2 ppm (als TWA); Krebskategorie A2 (Verdacht auf krebserzeugende Wirkung beim Menschen); (ACGIH 2008).
MAK: Krebserzeugend Kategorie 2; (DFG 2008).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation.
INHALATIONSGEFAHREN
Eine gesundheitsschädliche Konzentration des Gases in der Luft wird beim Entweichen aus dem Behälter sehr schnell erreicht.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz verätzt stark die Augen, die Haut und die Atemwege. Inhalation des Dampfes kann zu Lungenödem und Asthma führen (s.Anm.). Die Flüssigkeit kann Erfrierungen hervorrufen. Exposition oberhalb der Arbeitsplatzgrenzwerte kann zum Tod führen. ärztliche Beobachtung notwendig.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Wiederholte oder andauernde Inhalation kann asthmatische Beschwerden hervorrufen. Möglicherweise krebserzeugend für den Menschen.
LECKAGE
Gefahrenbereich verlassen! Fachmann zu Rate ziehen! Belüftung. Persönliche Schutzausrüstung: Vollschutzanzug mit umgebungsluftunabhängigem Atemschutzgerät.
R-Sätze Betriebsanweisung:
R45:Kann Krebs erzeugen.
S-Sätze Betriebsanweisung:
S53:Exposition vermeiden - vor Gebrauch besondere Anweisungen einholen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
Aussehen Eigenschaften
CH2N2. Dunkelgelbe, bei 23
oC siedende Flüssigkeit -> gelbes, nach feuchtem Laub riechendes, sehr giftiges Gas. Löslich in Ether.
Gefahren für Mensch und Umwelt
Diazomethan ist sehr explosiv. Bereits das Vorhandensein scharfer Kanten in der Apparatur kann eine Explosion initiieren. Über 100
oC thermische Zersetzung.
Diazomethan ist sehr giftig. Es greift Haut, Lunge und Augen an und ruft asthmatische Beschwerden hervor.
Kann Krebs erzeugen.
Schutzmaßnahmen und Verhaltensregeln
Nur im Abzug arbeiten! Möglichst nicht mit dem reinen Gas arbeiten (besser mit einer Lösung von Diazomethan z.B. in Ether). Schutzschilde (Splitterschutz) um die Apparatur aufstellen.
Schutzhandschuhe (nur als kurzzeitiger Spritzschutz).
Jeden direkten Kontakt mit Diazomethan vermeiden.
Verhalten im Gefahrfall
Bei Gasaustritt maximale Lüftungsstufe einstellen. Labor räumen. Zündquellen fernhalten.
Im Brandfall Sicherheitszone bilden. Explosionsgefahr!
Erste Hilfe
Nach Hautkontakt: Betroffene Körperstellen mit Wasser spülen.
Nach Augenkontakt: Mit Wasser mindestens 15 Minuten bei geöffnetem Augenlid spülen. Augenarzt!
Nach Einatmen: Frischluft. Arzt!
Nach Kleidungskontakt: Benetzte Kleidung sofort ausziehen.
Ersthelfer: siehe gesonderten Anschlag
Sachgerechte Entsorgung
Lösung von Diazomethan in etherische Carbonsäurelösung eintropfen (Bildung des Methylesters). Nach der Reaktion (Entfärbung) als Lösemittelabfall entsorgen.
Chemische Eigenschaften
Diazomethane is a flammable, yellow gas or
a liquid under pressure. Musty odor.
Verwenden
Powerful methylating agent for acidic Compounds such as carboxylic acids, phenols, enols. For syntheses with diazomethane see the reviews by Smith, Chem. Rev. 23, 193 (1938); Eistert, Z. Angew. Chem. 54, 99, 124 (1941) translated by Spangler in Newer Methods of Preparative Organic Chemistry (New York, 1948) p 513; J. S. Pizey, Synthetic Reagents vol. 2 (John Wiley, New York, 1974) pp 65-142.
Definition
ChEBI: The simplest diazo compound, in which a diazo group is attached to a methylene group.
Allgemeine Beschreibung
Yellow gas with a musty odor. Highly toxic by inhalation Shipped as a liquid under pressure.
Air & Water Reaktionen
Reacts with water, releasing nitrogen, more stable in ether or dioxane.
Reaktivität anzeigen
Diazomethane undergoes violent thermal decomposition. Above 200°C. the vapors may explode violently if rough glass surfaces are present. Explosions at low temperatures can occur if traces of organic matter are present. [J. Phys. Chem. 35:1403(1931)]. Produces explosions with alkali metals. Reacts with copper powder and to some extent all solid surfaces to produce nitrogen and solid white polymethylene. Reacts with dimethylaminodimethylarsine and trimethyltin in ether with vigorous foaming.
Health Hazard
Diazomethane vapor causes severe irritation of the skin, eyes, mucous membranes,
and lungs. It is considered to be a substance with poor warning properties, and the
effects of exposure may be delayed in onset. Symptoms of exposure may include
headache, chest pain, cough, fever, severe asthmatic attacks, and pulmonary edema,
which can be fatal. Exposure of the skin and mucous membranes to diazomethane
may cause serious burns.
Diazomethane is a powerful allergen. Prolonged or repeated exposure to
diazomethane can lead to sensitization of the skin and lungs, in which case asthma-
like symptoms or fever may occur as the result of exposure to concentrations of
diazomethane that previously caused no symptoms. Chronic exposure to
diazomethane has been reported to cause cancer in experimental animals, but this
substance has not been identified as a human carcinogen.
Note that diazomethane is often prepared in situ from precursors that may
themselves be highly toxic and/or carcinogenic.
Brandgefahr
Pure diazomethane gas and liquid are readily flammable and can explode easily. A
variety of conditions have been reported to cause explosions of diazomethane,
including contact with rough surfaces such as ground-glass joints, etched or
scratched flasks, and glass tubing that has not been carefully fire-polished. Direct
sunlight and strong artificial light may also cause explosions of this substance.
Violent reactions may occur on exposure of diazomethane to alkali metals.
Flammability and Explosibility
Pure diazomethane gas and liquid are readily flammable and can explode easily. A variety of conditions have been reported to cause explosions of diazomethane, including contact with rough surfaces such as ground-glass joints, etched or scratched flasks, and glass tubing that has not been carefully fire-polished. Direct sunlight and strong artificial light may also cause explosions of this substance. Violent reactions may occur on exposure of diazomethane to alkali metals.
Sicherheitsprofil
Confirmed carcinogen
with experimental tumorigenic data. A
poisonous irritant by inhalation. A powerful
allergen. It can cause pulmonary edema and
frequently causes hypersensitivity leading to
asthmatic symptoms. Mutation data
reported. Highly explosive when shocked,
exposed to heat, or by chemical reaction.
Undiluted liquid or gas may explode on
contact with alkali metals, rough surfaces,
heat (lOO°C), hgh-intensity light, or shock.
When heated to decomposition or on
contact with acid or acid fumes it emits
highly toxic fumes of NOx. Incompatible
with alkali metals; calcium sulfate.
mögliche Exposition
Diazomethane is a powerful methylat-
ing agent for acidic compounds, such as carboxylic acids,
phenols and enols. It is used in pesticide manufacture and
pharmaceutical manufacture.
Carcinogenicity
Diazomethane was administered
to rats and mice by inhalation, dermal, or subcutaneous
injection routes using concentrations of 0.1 or 3.3 mg/mL.
Mice developed lung tumors following either dermal application
or inhalation at both concentrations.
Lager
diazomethane should preferably be handled in solution using glassware specially designated for diazomethane (e.g., with Clear-Seal joints) and should be used as soon as possible after preparation. Storage of diazomethane solutions (even at low temperature) is not advisable. All work with diazomethane should be conducted in a fume hood behind a safety shield, and appropriate impermeable gloves, protective clothing, and safety goggles should be worn at all times.
Versand/Shipping
UN1953 Compressed gas, toxic, flammable, n.o.s.
Inkompatibilitäten
Heat (at about or above 100
C), shock,
friction, concussion, sunlight, or other intense illuminations
may cause explosions. Contact with alkali metals; drying
agents such as calcium sulfate, or rough edges (such as
ground glass) may cause explosions. Diazo compounds can
detonate. This applies in particular to organic azides that
have been sensitized by the addition of metal salts or strong
acids. Toxic gases are formed by mixing materials of this
class with acids, aldehydes, amides, carbamates, cyanides,
inorganic fluorides, halogenated organics, isocyanates,
ketones, metals, nitrides, peroxides, phenols, epoxides, acyl
halides, and strong oxidizing or reducing agents.
Flammable gases are formed by mixing materials in this
group with alkali metals. Explosive combination can occur
with strong oxidizing agents, metal salts, peroxides, and
sulfides. This chemical is sensitive to prolonged exposure
to heat. This chemical is incompatible with strong
oxidizing agents
.
Waste disposal
Decompose chemically
with ceric ammonium nitrate under constant agitation and
cooling
.
Vorsichtsmaßnahmen
Diazomethane is attractive as a methylating agent for carboxylic acids and phenols because it reacts quickly and highly efficiently with the production of only N2 as a by-product (Black, 1983). Its natural yellow color is discharged as it reacts, providing automatic indication of reaction progress. However, because diazomethane is highly toxic, it should be generated and used only in a well-functioning fume hood. Because it explodes on contact with some metals or ground glass of any type (joints, stoppers, syringes, stopcocks), it should be handled behind a safety shield, and other personal protective equipment should be used. Because it has a boiling point of ?23°C, it is usually handled in the ethereal solutions in which it is generated. Because it explodes on contact with CaSO4, its solutions or vapors must never be dried with drierite. Despite all of these hazards, it can be worked with safely, provided that appropriate precautions are observed.
Diazomethan Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
