74-90-8 Usage
Chemical Description
Hydrogen cyanide, potassium cyanide, and sodium diethyl cyanomethylphosphonate are all reagents used in the synthesis of these compounds.
Uses
Used in Chemical Production:
Hydrogen cyanide is used as a key intermediate in the manufacture of various chemical products and intermediates for organic syntheses. It is used in the production of acrylonitrile, acrylates, cyanide salts, dyes, rodenticides, and other pesticides.
Used in Fumigation:
Hydrogen cyanide is used as a horticultural fumigant and sometimes applied as a disinfectant in gas form or cellulosic disks impregnated with HCN.
Used in Ore Processing and Metal Treating:
In the mining industry, cyanides are widely used for ore processing and metal treating.
Used in Manufacturing Synthetic Fibers, Plastics, and Dyes:
Hydrogen cyanide is used as an intermediate in the production of synthetic fibers, plastics, and dyes.
Used in Producing Methyl Methacrylate, Cyanuric Chloride, and Triazines:
Hydrogen cyanide is used in the production of methyl methacrylate, cyanuric chloride, and triazines.
Used in Chelate Production:
Hydrogen cyanide is used in the production of chelates such as ethylenediaminetetraacetic acid (EDTA).
Used in Electroplating:
Hydrogen cyanide is used in the electroplating industry.
Sources:
Hydrogen cyanide occurs naturally in beet sugar residues, coke oven gas, and the roots of certain plants such as sorghum, cassava, and peach tree roots. It is also found in trace amounts in apricot seeds and tobacco smoke.
History
Hydrogen cyanide in pure form was prepared first in 1815 by Gay-Lussac.Earlier, in 1782, Scheel prepared HYDROGEN CYANIDE 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.
Production Methods
Hydrogen cyanide can be prepared from a mixture of NH3, methane, and air by partial combustion in the presence of a platinum catalyst: HN3 + CH4 + 1.5 O2 +6 N2 → HCN +3 H2O + 6N2 The process is carried out at about 900–1,000 °C; yield ranges from 55–60%. In another process, methane (contained in natural gas) is reacted with NH3 over a platinum catalyst at from 1,200–1,300 °C, the reaction requiring considerable heat input. In still another process, a mixture of methane and propane is reacted with NH3 : C3H8 + 3NH3 → 3HCN + 7H2; or CH4 + NH3 → HCN + 3H2. An electrically heated fluidized bed reactor is used. Reaction temperature is approximately 1,510 °C.
Production Methods
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).
Preparation
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:
2CH4 + 2NH3 + 3O2 → HCN + 3H2O ΔHrxn = 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 + H2O + H2
2. Thermal decomposition of formamide at elevated temperatures and reduced pressure:
HCONH2 → HCN + H2O
3. Heating acetonitrile and ammonia at 1,100 to 1,300°C:
CH3CN + NH3 → 2HCN +2H2
4. Reaction of sodium cyanide or potassium cyanide or potassium ferrocyanide with a mineral acid:
NaCN + HCl → HCN + NaCl
K4Fe(CN)6 + 6HCl → 6HCN + 4KCl + FeCl2
Reactions
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.
Reactivity Profile
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
TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
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.
Health Hazard
HCN is particularly dangerous because of its toxic and asphyxiating effects on all life
requiring oxygen to survive. HCN combines with the enzymes in tissue associated with
cellular oxidation. The signs and symptoms of HCN poisoning are non-specifi c and very
rapid. The symptoms include excitement, dizziness, nausea, vomiting, headache, weakness, drowsiness, gasping, thyroid, blood changes, confusion, fainting, tetanic spasm,
lockjaw, convulsions, hallucinations, loss of consciousness, coma, and death. When oxygen becomes unavailable to the tissues, it leads to asphyxia and causes death. Children are
more vulnerable to HCN exposure. HCN is readily absorbed from the lungs; symptoms of
poisoning begin within seconds to minutes. Inhalation of HCN results in the rapid onset
of poisoning, producing almost immediate collapse, respiratory arrest, and death within
minutes (Table 1)
Health Hazard
The acute toxicity of hydrogen cyanide is high, and exposure by inhalation,
ingestion, or eye or skin contact can be rapidly fatal. Symptoms observed at low
levels of exposure (e.g., inhalation of 18 to 36 ppm for several hours) include
weakness, headache, confusion, nausea, and vomiting. Inhalation of 270 ppm can
cause immediate death, and 100 to 200 ppm can be fatal in 30 to 60 min. Aqueous
solutions of HCN are readily absorbed through the skin and eyes, and absorption of
50 mg can be fatal. In humans, ingestion of 50 to 100 mg of HCN can be fatal.
Because there is wide variation in the ability of different individuals to detect the
odor of HCN, this substance is regarded as having poor warning properties.
Effects of chronic exposure to hydrogen cyanide are nonspecific and rare
Health Hazard
Hydrogen cyanide is a dangerous acute poison by all toxic routes. Acute inhalation may cause death in seconds. Lethal effects due to inhalation of its vapor depend on its concentration in air and time of exposure. Inhalation of 270 ppm HCN in air can be fatal to humans instantly, while 135 ppm can cause death after 30 minutes (Patty 1963; ACGIH 1986). Exposure to high concentration can cause asphyxia and injure the central nervous system, cardiovascular system, liver, and kidney. HCN is extremely toxic via ingestion, skin absorption, and ocular routes. Swallowing 50 mg can be fatal to humans. The symptoms of HCN poisoning at lethal dosage are labored breathing, shortness of breath, paralysis, unconsciousness, convulsions, and respiratory failure. At lower concentrations toxic effects are headache, nausea, and vomiting. LD50 value, intravenous (mice): 0.99 mg/kg LD50 value, oral (mice): 3.70 mg/kg Investigating the relationship between pH (in the range 6.8–9.3) and the acute toxicity of HCN on fathead minnow, Broderius et al. (1977) observed that similar to H2S, the toxicity of HCN increased at an elevated pH value. This was attributed to certain chemical changes occurring at the gill surface and possible penetration of the gill by both molecular and anionic forms. In an acute lethal toxicity study on the influence of exposure route, Ballantyne (1983a) observed that the blood cyanide concentrations varied with the route. Concentrations in certain specific tissues varied markedly with exposure route. The blood cyanide concentration was lowest by inhalation and skin penetration. For a given exposure route, the cyanide level in blood were similar for different species. Among the most toxic cyanides, HCN was more toxic than NaCN or KCN by intramuscular and transocular routes. Blank et al. (1983) carried out inhalation toxicity studies of hydrogen cyanide on Sprague-Dawley rats. Exposure at 68 ppm HCN in air 6 hours per day for three consecutive days showed symptoms of hypoactivity, breathing difficulties, signs of hypoxia, convulsions, and chromorhinorrhea. Death resulted in three of the five male rats after 1 day of exposure, caused by cyanosis of the extremities, moderate to severe hemorrhage of the lung, and pulmonary edema. All female rats survived. In a 4-week study, no mortality was observed at concentrations up to 58 ppm HCN. A brief exposure to 125 ppm HCN for 15 minutes, however, was fatal to 20% of the test animals. Increased urine thiocyanate levels were observed in test animals However, no adverse effects were observed in rats exposed at 29 ppm HCN 6 hour’s weekday in 4-week studies. Alarie and Esposito (1988) proposed a blood cyanide concentration of 1 mg/L as the fatal threshold value for HCN poisoning by inhalation. A cyanide concentration of 1.2 mg/L was measured in test animals exposed to nylon carpet smoke. The combined toxicities of fire-effluent gases CO and HCN was found to be additive (Levin et al. 1988). The study indicated that the sublethal concentrations of the individual gases became lethal when combined. Furthermore, the presence of CO2 combined with decreasing oxygen concentration enhanced the toxicity of the CO–HCN mixture (Levin et al. 1987). HCN and nitric oxide hastened the incapacitation in rats produced by carbon monoxide. Such incapacitation occurred at a carbonyl hemoglobin concentration of 42.2–49%; while for CO alone 50–55% carbonyl hemoglobin manifested the same effect (Conditet al. 1978).
Fire Hazard
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.
Fire Hazard
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
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.
storage
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.
Purification Methods
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.
Incompatibilities
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.
Precautions
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.
Check Digit Verification of cas no
The CAS Registry Mumber 74-90-8 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 7 and 4 respectively; the second part has 2 digits, 9 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 74-90:
(4*7)+(3*4)+(2*9)+(1*0)=58
58 % 10 = 8
So 74-90-8 is a valid CAS Registry Number.
InChI:InChI=1/CN/c1-2/q-1/p+1
74-90-8Relevant academic research and scientific papers
Goates, S. R.,Chu, J. O.,Flynn, G. W.
, p. 4521 - 4525 (1984)
Infrared emission from the ν2 bending mode and ν3 C-H stretching mode of HCN have been observed following 193 nm pulsed excimer laser photolysis of 1,3,5-triazine.Using a simple harmonic oscillator analysis, the number of ν2 bending quanta produced in HCN from photolysis of sym-triazine was found to be 70 times larger than the number of ν3 C-H stretching quanta.The combination of a high density of bending vibrational states in HCN and favorable geometry changes which occur in going from 1,3,5-triazine to three HCN molecules, appear to give an unusually pure distribution which maximizes vibrational energy in the HCN bending mode.
Khriachtchev, Leonid,Pettersson, Mika,Raesaenen, Markku
, p. 727 - 733 (1998)
UV photolysis of small molecules embedded in rare-gas matrices is examined. We demonstrate that photolysis can be self-limited when products absorb the photolysing radiation. As a result of the rising absorption, in-situ detected luminescence of the photolysis product saturates faster than its concentration. In particular, the present study supports the conclusion that 193 nm photolysis of hydrogen-containing species in Xe matrices produces hydrogen atoms in amounts comparable with the other dissociating part of the precursor. Also, we show that 193 nm radiation activates mobility of hydrogen atoms in annealing, accelerating photochemical processes related to hydrogen mobility.
Liu, Yueh-Ling,Takahashi, Masao,Kobayashi, Hikaru
, p. H16-H19 (2007)
The mechanism of Ni removal from Si O2 -covered Si specimens by HCN aqueous solutions has been investigated by means of total reflection X-ray fluorescence spectroscopy and X-ray photoelectron spectroscopy measurements. Ni contaminants on the Si O2 surface are present in the form of SiO-NiOH. The removal mechanism consists of two steps, i.e., an initial fast process followed by a slow process. The rate-determining steps of both the processes are of the first order with respect to the concentration of cyanide ions (C N-). The fast and slow processes are tentatively attributed to the removal of SiO-NiOH on terraces and in sub-nanometer pores, respectively. The cleaning ability of the HCN aqueous solutions is much better than ammonia aqueous solutions, because of high reactivity to form nickel-cyanide complex ions and avoidance of readsorption of Ni (CN) 4 2- complex ions in the solutions.
Bohn, Robert B.,Andrews, Lester
, p. 3974 - 3979 (1989)
The NH3--HCN complex has been observed and characterized in an argon matrix.It is a strongly bonded complex with C3v geometry.New absorptions attributable to perturbed vibrations in each submolecule have been observed, especially a new red-shifted absorption νc3(CH) for the perturbed C-H stretching fundamental with blue-shifted absorptions assigned to νc1(CN), νc2(HCN), and νc2(NH3).A low-frequency absorption assigned to the librational motion of HCN in the complex was also observed and agrees well with calculated results.Comparison with the gas-phase spectrum shows that the matrix interaction stabilizes the complex.Spectra for the higher order 1:2 NH3--(HCN)2 complexes are presented, assigned, and compared to NH3--HCN and (HCN)2.
Kuznetcova, Anastasiya V.,Odin, Ivan S.,Golovanov, Alexander A.,Grigorev, Iakov M.,Vasilyev, Aleksander V.
, p. 4516 - 4530 (2019)
Reaction of conjugated enynones,1,5-diarylpent-2-en-4-yn-1-ones, with malononitrile and sodium alkoxides in the corresponding alcohols at room temperature for 3–23 h results in the formation of two types of compounds (E)-/(Z)-6-aryl-4-(2-arylethenyl)-2-alkoxypyridine-3-carbonitriles (substituted nicotinonitriles), as the major reaction products in yields up to ca. 40–80%, and 6-aryl-4-arylethynyl-2-alkoxypyridines, as the minor reaction products in yields of 5–17%. Plausible mechanism of this complex and multistep reaction is discussed. The obtained pyridines possess fluorescent properties.
Satoshi, Kudoh,Takayanagi, Masao,Nakata, Munetaka
, p. 365 - 369 (1997)
The infrared spectra of the HCN monomer, linear (HCN)2 and cyclic (HCN)3 were measured using a low-temperature matrix isolation technique. Linear (HCN)2 and cyclic (HCN)3 were produced by the photolysis of s-tetrazine and s-triazine respectively. Vibrational analyses of the infrared bands for the C-H stretching, the C-N stretching and H-C-N bending modes were performed with the aid of ab initio calculations; geometrical optimization was carried out using the density functional theory (DFT) method with a 6-31++G** basis set.
Parent, Denise C.,McElvany, Stephen W.
, p. 2393 - 2401 (1989)
The results of a detailed study of the primary and secondary reactions of carbon cluster ions, Cn(1+) (3=20), with HCN are used as a probe of the structures of small carbon cluster ions.The experiments were performed in a Fourier transform ICR mass spectrometer (FTMS), using direct laser vaporization of graphite to form the carbon cluster ions.The only ionic products observed for the HCN reactions were CnX(1+) (primary reaction product) and CnXY(1+) (secondary reaction product) where X and Y = H, CN, or HCN.Radiative association is an important reaction channel.Products resulting from fragmentation of the reactant carbon cluster ion were not observed.Evidence for two structural forms of the n = 7-9 cluster ions is presented.The anomalous behavior of C7(1+) is interpreted by an isomerization mechanism.Low-energy collision-induced dissociation studies of the primary product ions support a mechanism of carbene insertion into the H-CN bond and formation of covalently bonded products.In contrast, the HCN associates weakly with most primary product ions.
Andrews, Steven S.,Boxer, Steven G.
, p. 11853 - 11863 (2000)
The C-N stretch mode of several small nitriles was analyzed by measuring vibrational Stark effects. Conjugated and unconjugated nitriles as well as mono- and dinitriles were immobilized in frozen 2-methyl-tetrahydrofuran glass and examined in externally applied electric fields using FTIR. Room temperature absorption spectra of several nitriles (butyronitrile, hydrogen cyanide, valeronitrile, and deuterated aceonitrile) showed no concentration dependent effects between 2.4 mM and 0.8 M. Difference dipole moments, Δμ, equivalent to the linear Stark tuning rate, were 0.01/f-0.04/f Debye (0.2/f-0.7/f/cm(/MV/cm)) for most samples, with aromatic compounds toward the high end and symmetric dinitriles toward the low end. Most quadratic Stark effects were small and negative, while transition polarizabilities were positive and had a significant effect on Stark line shapes. For aromatic nitriles, transition dipoles and Δμ values agreed with Hammett numbers. Symmetric dinitrile Δμ values decreased monotonically with increasing conjugation of the connecting bridge, likely due to improved mechanical coupling and, to a lesser extent, an increased population of inversion symmetric conformations. Δμ values were close to those expected from bond anharmonicity and ab initio predictions.
Fujii, Toshihiro
, p. 733 - 740 (1999)
The production of gaseous hydrocarbons, nitriles, amines, and hydrazines in a continuous-flow microwave plasma discharge excited in a 20% C2H2+80% N2 mixture at a pressure of 20 Torr is reported. The product analysis was made by Li+ ion attachment mass spectrometry. A variety of N-containing organics (identified as HCnN (n=1-7), NC(CC)nCN (n=0-2), NC(CH2)nCN (n=0-6), CnH2n-1NH2 (n=0-6), CnH2n+1N(H)NH2 (n=0-5), etc.) were formed and these were tentatively assigned to nitriles, amines, and hydrazines. The mass-spectral analysis exhibited progressions differing by 14 mass units. Reaction schemes were proposed to explain the formation of some molecules.
Hodny, Michael,Hershberger, John F.
, p. 88 - 91 (2016)
The kinetics of the CN + CH3Br reaction were studied using transient infrared laser absorption spectroscopy to detect CN reactants and HCN products. This reaction has a rate constant of k = (2.20 ± 0.6) × 10-12 exp (453 ± 98/T) cm3 molecule-1 s-1 over the range 298-523 K. Hydrogen abstraction to produce HCN + CH2Br is only a minor reaction product, with a branching fraction of 0.12 ± 0.02. Other product channels, including BrCN + CH3, CH2CN + HBr, CH3CN + Br are likely. An upper limit of 0.01 was established for the HBr yield. These results are in qualitative agreement with recent ab initio calculations.
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