Cyanwasserstoff Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
FARBLOSES GAS ODER FLüSSIGKEIT MIT CHARAKTERISTISCHEM GERUCH.
PHYSIKALISCHE GEFAHREN
Das Gas mischt sich gut mit Luft. Bildung explosionsf?higer Gemische.
CHEMISCHE GEFAHREN
Kann polymerisieren beim Erhitzen, unter Einfluss von Basen, bei einem Wassergehalt von über 2% oder in nicht chemisch stabilisierter Form. Feuer- und Explosionsgefahr. Beim Verbrennen Bildung giftiger und ?tzender Gase mit Stickstoffoxiden. Schwache S?ure in w?ssriger L?sung. Reagiert sehr heftig mit Oxidationsmittelnund Chlorwasserstoff in alkoholischen Gemischen unter Feuer- und Explosionsgefahr.
ARBEITSPLATZGRENZWERTE
TLV: 4.7 ppm; (als STEL, ceiling); Hautresorption; (ACGIH 2005).
MAK: 1.9 ppm, 2.1 mg/m? Hautresorption; Spitzenbegrenzung: überschreitungsfaktor II(2); Schwangerschaft: Gruppe C; (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den K?rper durch Inhalation, über die Haut und durch Verschlucken.
INHALATIONSGEFAHREN
Beim Verdampfen bei 20°C tritt sehr schnell eine gesundheitssch?dliche Kontamination der Luft ein.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz reizt die Augen und die Atemwege. M?glich sind Auswirkungen auf die Zellatmung mit nachfolgenden Kr?mpfen und Bewusstlosigkeit. Exposition kann zum Tod führen. ?rztliche Beobachtung notwendig. (s.Anm.)
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
M?glich sind Auswirkungen auf die Schilddrüse.
LECKAGE
Gefahrenbereich sofort verlassen! Fachmann zu Rate ziehen! Belüftung. Zündquellen entfernen. Reste mit Sand oder inertem Absorptionsmittel aufnehmen und an einen sicheren Ort bringen. Wasserstrahl NIEMALS auf die Flüssigkeit richten. NICHT in die Umwelt gelangen lassen. Gasdichter Chemikalienschutzanzug mit umgebungsluftunabh?ngigem Atemschutzger?t.
R-S?tze Betriebsanweisung:
R12:Hochentzündlich.
R26:Sehr giftig beim Einatmen.
R50/53:Sehr giftig für Wasserorganismen, kann in Gew?ssern l?ngerfristig sch?dliche Wirkungen haben.
R26/27/28:Sehr giftig beim Einatmen, Verschlucken und Berührung mit der Haut.
S-S?tze Betriebsanweisung:
S7/9:Beh?lter dicht geschlossen an einem gut gelüfteten Ort aufbewahren.
S16:Von Zündquellen fernhalten - Nicht rauchen.
S36/37:Bei der Arbeit geeignete Schutzhandschuhe und Schutzkleidung tragen.
S38:Bei unzureichender Belüftung Atemschutzger?t anlegen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn m?glich, dieses Etikett vorzeigen).
S60:Dieses Produkt und sein Beh?lter sind als gef?hrlicher Abfall zu entsorgen.
S61:Freisetzung in die Umwelt vermeiden. Besondere Anweisungen einholen/Sicherheitsdatenblatt zu Rate ziehen.
Aussehen Eigenschaften
HCN (Blausäure); farblose Flüssigkeit oder Gas mit metallisch fadem Geschmack und Bittermandelgeruch. Gut wasserlöslich.
Gefahren für Mensch und Umwelt
Hochentzündlich.
In flüssiger, nicht stabilisierter Form neigt der Stoff zu spontaner, explosionsartiger Polymerisation, besonders in Gegenwart von alkalischen Verbindungen, Metalloxiden oder bei Wärmeeinwirkung. Weitere heftige z.T. explosionsartige Reaktionen mit NH
4Cl, Cl
2, F
2, HCl und O
2. Bildet mit Luft explosionsfähige Gemische.
Sehr giftig beim Einatmen. Wirksamer Bestandteil ist das Cyanid-Ion. Blausäure ist auf allen Wegen leicht resorbierbar, auch durch die Haut. Blockiert die Zellatmung. Die Folge ist neben lokaler Reizwirkung eine innere Erstickung. Bei akuter Aufnahme können Cyanid-Dosen ab 0,7mg/kg tödlich wirken. Hautresorption des Gases ab etwa 1 Vol%.
Bei Inhalation Auftreten erster Symptome schon nach Sekunden (Kratzen im Hals, Angstgefühl, Herzklopfen, Schwäche, Bewußtseinsverlust, RRotfärbung von Haut und Schleimhäuten. Erbrechen möglich. Geruch der Atemluft nach Bittermandel. Bei nichttödlicher Vergiftung rasche Erholung, meist ohne Spät- und Dauerfolgen.
Schutzma?nahmen und Verhaltensregeln
Behälter dicht geschlossen an einem gut belüfteten Ort aufbewahren. Von Zündquellen fernhalten.
Schutzhandschuhe (nur als kurzzeitiger Spritzschutz).
Verhalten im Gefahrfall
Labor räumen! Benachbarte Bereiche warnen! Weitere Maßnahmen im Gefahrenbereich nur mit umgebungsluftunabhängigem Atemschutz. Feuerwehr rufen.
Kleine Brände nur von außen naß halten, nicht löschen. Gas abbrennen lassen.
Erste Hilfe
Nach Hautkontakt: Mit viel Wasser abwaschen.
Nach Augenkontakt: Mindestens 15 Minuten bei geöffnetem Lidspalt unter fließendem Wasser spülen. Augenarzt!
Nach Einatmen: Frischluft; Sauerstoffgabe. Ggf. Atemspende bzw. Gerätebeatmung. Sofort Notarzt rufen!
Nach Kleidungskontakt: Benetzte Kleidung ausziehen.
Rasches Handeln kann lebensrettend sein.
Ersthelfer: siehe gesonderten Anschlag
Sachgerechte Entsorgung
Cyanidhaltige wässrige Lösungen mit Hypochlorit behandeln; entgiftete Lösung kann ins Abwasser gegeben werden.
Beschreibung
Hydrocyanic acid, HCN, is corrosive in addition to toxic. It is also a dangerous fire and explosion risk. It has a wide flammable range of 6%–41% in air. The boiling point is 79°F (26°C), the flash point is 0°F, and the ignition temperature is 1004°F (540°C). It is toxic by inhalation and ingestion and through skin absorption. The TLV of hydrocyanic acid is 10 ppm in air. It is used in the manufacture of acrylonitrile, acrylates, cyanide salts, dyes, rodenticides, and other pesticides.
Chemische Eigenschaften
Water-white liquid at temperatures
below 26.5°C; sweet odor reminiscent of mashed Bitter
Almonds, but more woody and delicate. Usual
commercial material is 96–99% pure. Soluble in
water. The solution is weakly acidic, sensitive
to light. When not absolutely pure or stabilized, hydrogen cyanide polymerize.
Physikalische Eigenschaften
Colorless liquid or gas; odor of bitter almond; burns in air with a blue flame;refractive index 1.2675; autoignition temperature 538°C; vapor density at31°C 0.947 (air=1); liquid density 0.715 g/mL at 0°C and 0.688 g/mL at 20°C;boils at 25.7°C; melts at 13.24°C; vapor pressure 264 torr at 0°C; critical tem-perature 183.5°C; critical pressure 53.20 atm; critical volume 139 cm
3/moldielectric constant 158.1 at 0°C and 114.9 at 20°C; conductivity 3.3 mhos/cmat 25°C; viscosity 0.201 centipoise at 20°C; surface tension 19.68 dyn/cm;readily mixes with water and alcohols; density of a 10% aqueous solution0.984 g/mL at 20°C; pKaat 25°C 9.21.
Occurrence
Peaches, apricots, bitter almonds, cherries, and plums contain some HCN derivatives in their kernels, frequently in combination with glucose and benzaldehyde as a glucoside (amygdalin). The bitter almond fragrance of HCN and its derivatives sometimes can be detected in such kernels.
History
Hydrogen cyanide in pure form was prepared first in 1815 by Gay-Lussac.Earlier, in 1782, Scheel prepared this compound in dilute solution. The mostimportant application of hydrogen cyanide is to produce methyl methacrylatefor methacrylate resins and plastics. Other products made from hydrogencyanide include potassium cyanide, sodium cyanide, adiponitrile, methionine,cyanuric chloride, cyanogen, nitrilotriacetic acid, and several triazine pesti-cides. The compound also is used in small amounts for extermination ofrodents.
Verwenden
HCN was first isolated from a blue dye, Prussian blue, in 1704. HCN is obtainable from fruits that have a pit, such as cherries, apricots, and bitter almonds, from which almond oil and flavouring are made. HCN is used in fumigating, electroplating, mining, and producing synthetic fibres, plastics, dyes, and pesticides. It also is used as an intermediate in chemical syntheses.
Besides, hydrogen cyanide is used in manufacturing cyanide salts, aerylonitrile,and dyes.It is also used as a horticultural fumigant.
synthetische
Hydrogen cyanide is generally produced in industrial quantities by hightemperature catalytic reaction between ammonia, methane, and air (theAndrussow process). The stoichiometry of the process is:
2CH
4 + 2NH
3 + 3O
2 → HCN + 3H
2O ΔH
rxn = 230.4 kcal
The above reaction is endothermic requiring a temperature of 1,100°C and acatalyst such as platinum or rhodium. Other hydrocarbons may be usedinstead of methane.
The compound may be made by several other methods, which include:1. Heating methanol and ammonia in the absence of air at elevated temperatures (600 to 950°C) using a catalyst:
CH3OH + NH3 → HCN + H
2O + H
2
2. Thermal decomposition of formamide at elevated temperatures and reduced pressure:
HCONH
2 → HCN + H
2O
3. Heating acetonitrile and ammonia at 1,100 to 1,300°C:
CH
3CN + NH
3 → 2HCN +2H
2
4. Reaction of sodium cyanide or potassium cyanide or potassium ferrocyanide with a mineral acid:
NaCN + HCl → HCN + NaCl
K
4Fe(CN)
6 + 6HCl → 6HCN + 4KCl + FeCl
2
Definition
ChEBI: A one-carbon compound consisting of a methine group triple bonded to a nitrogen atom. Also known as formonitrile, hydrogencyanide and prussic acid,HCN is a highly toxic liquid that has the odor of bitter almonds and boils at 25.6 °C.
also known as hydrocyanic acid, prussic acid, and fonnonitrile, is a very poisonous colorless gas with a characteristic fragrance of bitter almonds. Small amounts of hydrogen cyanide derivatives in combination with glucose and benzaldehyde are found in nature in apricot,peach,cherry, and plum pits.It liquifies at 26°C (79 OF) and is soluble in water,alcohol,and ether. Hydrogen cyanide is usually sold commercially as an aqueous solution containing 2 to 10% hydrogen cyanide. HCN reacts with amines, oxidisers, acids, sodium hydroxide, calcium hydroxide, sodium carbonate, caustic substances, and ammonia. The aqueous solutions of hydrogen cyani dedecompose slowly to form anunonium formate. In some uses, it is preferable to generate hydrogen cyanide as needed, thus eliminating handling and storage problems.
Vorbereitung Methode
Hydrogen cyanide has been manufactured from sodium
cyanide and mineral acid and from formamide by catalytic
dehydration. Two synthesis processes account for most of the
hydrogen cyanide produced. The dominant commercial process
for direct production of hydrogen cyanide is based on
classic technology involving the reaction of ammonia,
methane (natural gas), and air over a platinum catalyst; it
is called the Andrussow process. The second process, which involves the reaction of ammonia and methane, is called the
Blaus€aure–Methan–Ammoniak (BMA) process;
it was developed by Degussa in Germany. Hydrogen cyanide
is also obtained as a by-product in the manufacture of
acrylonitrile by the ammoxidation of propylene (Sohio
process).
Reaktionen
Hydrogen cyanide reacts with hydrogen at 140 °C in the presence of a catalyst, e.g., platinum black, to form methyl amine CH3NH2. When burned in air, it produces a pale violet flame; when heated with dilute sulfuric acid, it forms formamide HCONH2 and ammonium formate HCOONH4; when exposed to sunlight with chlorine it forms cyanogen chloride CNCl, plus hydrogen chloride. An important reaction of hydrogen cyanide is that with aldehydes or ketones, whereby cyanhydrins are formed, e.g., acetaldehyde cyanhydrin CH3CHOH·CH, and the resulting cyanhydrins are readily converted into alpha-hydroxy acids, e.g., alphahydroxypropionic acid CH3·CHOH·COOH.
Allgemeine Beschreibung
Hydrocyanic acid solution is water containing up to 5% dissolved hydrocyanic acid with the faint odor of almonds. HYDROGEN CYANIDE is toxic by inhalation and skin absorption. Prolonged exposure to low concentrations or short term exposure to high concentrations may result in adverse health effects. Its vapors are just barely lighter than air.
Reaktivit?t anzeigen
This particular record contains hydrogen cyanide dissolved in water. Hydrogen cyanide is a very volatile liquid or colorless gas smelling of bitter almonds, b.p. 26° C. A deadly human poison by all routes. The gas (hydrogen cyanide) forms explosive mixtures with air, HYDROGEN CYANIDE reacts violently with acetaldehyde. HYDROGEN CYANIDE is a severe explosion hazard when heated or exposed to oxidizers. HYDROGEN CYANIDE may polymerize explosively at elevated temperature (50-60° C) or in the presence of traces of alkali [Wohler, L. et al., Chem. Ztg., 1926, 50, p. 761, 781]. In the absence of a stabilizer (e.g., phosphoric acid) HYDROGEN CYANIDE may undergo explosively rapid spontaneous (autocatalytic) polymerization leading to a fire. The reaction is autocatalytic because of ammonia formation. The anhydrous acid should be stabilized by the addition of acid. [Bond, J., Loss Prev. Bull., 1991, 101, p.3]. During the preparation of imidoester hydrochlorides, hydrogen chloride was rapidly passed over alcoholic hydrogen cyanide. An explosion ensued, even with cooling of the process, [J. Org. Chem., 1955, 20, 1573].
Hazard
Flammable, dangerous fire risk, explosive
limits in air 6–41%. Toxic by ingestion, inhalation,
and skin absorption. TLV: ceiling 4.7 ppm.
Health Hazard
Exposures to hydrogen cyanide cause adverse health effects to animals and humans.
Hydrogen cyanide is readily absorbed from the lungs and the symptoms of poisoning
begin within seconds to minutes. The symptoms of toxicity and poisoning include, but
are not restricted to, asphyxia, lassitude or weakness, exhaustion, headache, confusion,
nausea, vomiting, increased rate and depth of respiration, or respiration slow and gasp-
ing, thyroid and blood changes. Inhalation of hydrogen cyanide causes headache, dizzi-
ness, confusion, nausea, shortness of breath, convulsions, vomiting, weakness, anxiety,
irregular heart beat, tightness in the chest, and unconsciousness, and these effects may be
delayed. The target organs of induced toxicity and poisoning include the CNS, cardiovas-
cular system, thyroid, and blood.
Brandgefahr
Hydrogen cyanide is a highly flammable liquid. Liquid HCN contains a stabilizer
(usually phosphoric acid), and old samples may explode if the acid stabilizer is not
maintained at a sufficient concentration.
Flammability and Explosibility
Hydrogen cyanide is a highly flammable liquid. Liquid HCN contains a stabilizer
(usually phosphoric acid), and old samples may explode if the acid stabilizer is not
maintained at a sufficient concentration.
Lager
Hydrogen cyanide should be stored in a cool, dry, well-ventilated area in tightly sealed
containers and with the correct label. Containers of hydrogen cyanide should be protected
from physical damage and should be stored separately from amines and oxidizers, such
as perchlorates, peroxides, permanganates, chlorates, and nitrates. It should be kept sepa-
rated from strong acids, such as hydrochloric, sulfuric, and nitric acids, away from sodium
hydroxide, calcium hydroxide, sodium carbonate, water, ammonia, acetaldehyde, and
caustics.
l?uterung methode
HCN is prepared from NaCN and H2SO4, and dried by passage through H2SO4 and over CaCl2, then distilled in a vacuum system and degassed at 77oK before use [Arnold & Smith J Chem Soc, Faraday Trans 2 77 861 1981]. Cylinder HCN may contain stabilisers against explosive polymerisation, together with small amounts of H3PO4, H2SO4, SO2, and water. It can be purified by distillaton over P2O5, then frozen in Pyrex bottles at Dry-ice temperature for storage. [Zeigler Org Synth Coll Vol I 314 1941, Glemser in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I pp 658-660 1963.] Liquid HCN, like liquid ammonia, evaporates very slowly since the latent heat of evaporation is high and keeps it in the liquid state because the temperature of the liquid is lowered to below its boiling point. EXTREMELY POISONOUS; all due precautions should be taken.
Inkompatibilit?ten
HCN can polymerize explosively if heated above 50 °C or in the presence of trace
amounts of alkali.
Waste disposal
In the event of a spill, remove all ignition sources. Cleanup should be conducted
wearing appropriate chemical-resistant clothing and respiratory protection
Disposal Excess hydrogen cyanide and waste material containing this substance should be
placed in an appropriate container, clearly labeled, and handled according to your
institution's waste disposal guidelines. For more information on disposal procedures,
see Chapter 7 of this volume.
Vorsichtsma?nahmen
Occupational workers should be very careful in the management of HCN since the gas in
air is explosive at concentrations over 5.6%, equivalent to 56,000 ppm and it does not provide adequate warning of hazardous concentrations. HCN at a concentration of 300 mg/m3
in air becomes fatal within about 10 min and HCN at a concentration of 3500 ppm (about
3200 mg/m3
) kills a human in about 1 min.
Cyanwasserstoff Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
Kupfercyanid
Bittermandel?l, blaus?urehaltiges
2-Cyanopropan-2-ol
Natriumsarkosinat
2,2'-Azobis[2,4-dimethylvaleronitril]
L-Valin
Isophthals?uredinitril
α-Hydroxy-β,β-dimethyl-γ-butyrolacton
2,2-Dimethyl-1,3-dioxolan-4-ylmethanol
L-Alanin
Hydroxyacetonitril
Deltamethrin
Glycin
(±)-Dihydro-3-hydroxy-4,4-dimethylfuran-2(3H)-on
Atrazin
Natriumcyanid
Silbercyanid
Tetranatriumhexacyanoferrat
Glyphosat
Milchsure
Iminodi(essigsure)
DL-CARNITINE
Acrylnitril
2-Methyl-2-propanamin
Methylmethacrylat
DL-Alanin
Methacrylsure
Methacryls?ureamid
Kaliumcyanid
Glykolsaeure
2,4,6-Trichlor-1,3,5-triazin
Edetinsure
Isobutyronitril
