74-90-8 Usage
Chemical Description
Hydrogen cyanide, potassium cyanide, and sodium diethyl cyanomethylphosphonate are all reagents used in the synthesis of these compounds.
Description
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.
Chemical Properties
Different sources of media describe the Chemical Properties of 74-90-8 differently. You can refer to the following data:
1. Water-white liquid at temperatures
below 26.5C; faint odor of bitter almonds. 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
2. HCN is a colorless to pale blue liquid or gas. It has a distinct odor resembling bitter
almonds. HCN reacts with amines, oxidizers, acids, sodium hydroxide, calcium hydroxide, sodium carbonate, caustic substances, and ammonia. HCN was fi rst 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 fl avoring are made. HCN
is used in fumigating, electroplating, mining, and in producing synthetic fi bers, plastics,
dyes, and pesticides. It is also used as an intermediate in chemical syntheses. Exposures
to cyanide occur in workplaces such as the electroplating, metallurgical, fi refi ghting, steel
manufacturing, and metal cleaning industries. Human exposures to cyanide also occur
from wastewater discharges of industrial organic chemicals, iron and steel works, and
wastewater treatment facilities
3. Hydrocyanic acid (hydrogen cyanide) is a clear colorless liquid with a faint odor of bitter
almonds. It evaporates easily (or boils) at room temperature and the vapors are slightly
lighter than air. It is soluble in water. It is reactive and incompatible with amines, oxi-
dizers, acids, sodium hydroxide, calcium hydroxide, sodium carbonate, caustics, and
ammonia.
Hydrogen cyanide is manufactured by the oxidation of ammonia–methane mixtures
under controlled conditions and by the catalytic decomposition of formamide. It may
be generated by treating cyanide salts with acid, and it is a combustion by-product of
nitrogen-containing materials such as wool, silk, and plastics. It is also produced by enzy-
matic hydrolysis of nitriles and related chemicals. Hydrogen cyanide gas is a by-product
of coke-oven and blast furnace operations. Industrial applications of hydrogen cyanide are
many. For instance, in fumigation, electroplating, mining, metallurgical, fi refi ghting, steel
manufacturing, and metal cleaning industries, to producing synthetic fi bers, plastics, dyes,
pesticides, and also as an intermediate in chemical syntheses.
Physical properties
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 cm3/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.
Uses
Different sources of media describe the Uses of 74-90-8 differently. You can refer to the following data:
1. Hydrogen cyanide is used to produce methyl methacrylate, cyanuric chloride, triazines, sodium cyanide, and chelates such as ethylenediaminetetraacetic acid (EDTA); and in fumigation. It occurs in beet sugar residues and coke oven gas. It occurs in the roots of certain plants, such as sorghum, cassava, and peach tree roots (Adewusi and Akendahunsi 1994; Branson et al. 1969; Esquivel and Maravalhas 1973; Israel et al. 1973) and in trace amounts in apricot seeds (Souty et al. 1970) and tobacco smoke (Rickert et al. 1980). Suchard et al. (1998) have reported a case of acute cyanide poisoning caused by ingestion of apricot kernel. The symptoms were weakness, dyspnea, comatose, and hypothermia observed within 20 minutes of ingestion. Firefighters chance a great risk to the exposure to HCN, which is a known fireeffluent gas. Materials such as polyurethane foam, silk, wool, polyacrylonitrile, and nylon fibers burn to produce HCN (Sakai and Okukubo 1979; Yamamoto 1979; Morikawa 1988; Levin et al. 1987; Sumi and Tsuchiya 1976) along with CO, acrolein, CO2, formaldehyde, and other gases. Emissions of these toxic gases take place primarily under the conditions of oxygen deficiency, and when the air supply is plentiful the emissions are decreased considerably (Hoschke et al. 1981). Bertol et al. (1983) determined that 1 g of polyacrylonitrile generated 1500 ppm of HCN. Thus a lethal concentration of HCN could be obtained by burning 2 kg of polyacrylonitrile in an average-sized living room. Jellinek and Takada (1977) reported evolution of HCN from polyurethanes as a result of oxidative thermal degradation while no HCN evolved from pure thermal degradation. Copper inhibited HCN liberation due to the catalytic oxidation of evolved HCN. Herrington (1979) observed that the isocyanate portion of polyurethane foam volatilizes first, releasing heat, smoke, HCN, nitrogen oxides, and organic compounds. Volatilization of polyolefin portion occurs next, releasing CO and CO2. Kishitani and Nakamura (1974) reported that the largest amount of HCN was evolved from urethane foam at 500°C (932°F), whereas with polyacrylonitrile and nylon 66, the amount of HCN increased with increasing temperature.
2. The high-tonnage uses of HCN are in the preparation of numerous chemical products and intermediates for organic syntheses. As a gas, HCN sometimes is applied as a disinfectant; or cellulosic disks impregnated with HCN may be used. In ore processing and metal treating, cyanides are widely used.
3. 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.
Definition
Different sources of media describe the Definition of 74-90-8 differently. You can refer to the following data:
1. 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.
2. A highly poisonous
weak acid formed when hydrogen cyanide
gas dissolves in water. Its salts are
cyanides. Hydrogen cyanide is used in
making acrylic plastics.
3. An addition
compound formed between an aldehyde
or ketone and hydrogen cyanide. The
general formula is RCH(OH)(CN) (from
an aldehyde) or RR′C(OH)(CN) (from a
ketone). Cyanohydrins are easily hydrolyzed
to hydroxycarboxylic acids. For
instance, the compound 2-hydroxypropanonitrile
(CH3CH(OH)(CN）) is hydrolyzed
to 2-hydroxypropanoic acid
(CH3CH(OH)(COOH)).
4. prussic acid: A colourless liquidor gas, HCN, with a characteristicodour of almonds; r.d. 0.699 (liquid at22°C); m.p. –14°C; b.p. 26°C. It is anextremely poisonous substanceformed by the action of acids onmetal cyanides. Industrially, it is madeby catalytic oxidation of ammonia and methane with air and is used inproducing acrylate plastics. Hydrogencyanide is a weak acid (Ka = 2.1 × 10-9mol dm-3). With organic carbonylcompounds it forms cyanohydrins.
Production Methods
Different sources of media describe the Production Methods of 74-90-8 differently. You can refer to the following data:
1. 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.
2. 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.
General Description
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.
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
Different sources of media describe the Health Hazard of 74-90-8 differently. You can refer to the following data:
1. 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.
2. 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.
3. 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)
4. 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
5. 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
Different sources of media describe the Fire Hazard of 74-90-8 differently. You can refer to the following data:
1. 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.
2. 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 articles and documents
-
Howard,Hilbert
, p. 1918,1921, 1922 (1938)
-
Observation of high vibrational excitation in HCN molecules produced from 193 nm photolysis of 1,3,5-triazine
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.
King, C. M.,Nixon, E. R.
, p. 1685 - 1695 (1968)
Multicomponent reaction of conjugated enynones with malononitrile and sodium alkoxides: Complex reaction mechanism of the formation of pyridine derivatives
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.
Yates,Heider
, p. 4153 (1952)
Investigations of Small Carbon Cluster Ion Structures by Reactions with HCN
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.
Analysis of products from a C2H2/N2 microwave discharge: New nitrile species
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.
Charge-transfer complexes of hypoglycemic sulfonamide with π-acceptors: Experimental and DFT-TDDFT studies
Soltani, Sara,Magri, Pierre,Rogalski, Marek,Kadri, Mekki
, p. 105 - 116 (2019)
Charge-transfer interactions (CT) between the electron donor gliclazide (GLC) and the π-acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tetracyanoethylene (TCNE) were studied in a chloroform solution and in the solid state. The CT complexes were discussed in terms of formation constants (KCT), molar extinction coefficients (εCT), standard reaction quantities (ΔG° ΔH° and ΔS°), oscillator strength (f), transition dipole moment (μEN), and ionization potential (Ip). The limits of detection (LOD) and limits of quantification (LOQ) have also been reported. The stoichiometry of these complexes was found to be in a 1:1 M ratio. The formed solid CT complexes were also synthesized and characterized using electronic methods, FT-IR, 1H and 13C NMR spectroscopy. Thermogravimetric analysis techniques (TGA/DTA) and differential scanning calorimetry (DSC) were used to determine the thermal stability of the synthesized CT complex. The kinetic parameters (ΔG* ΔH* and ΔS*) were calculated from thermal decomposition data using the Coats-Redfern method. Moreover, density functional theory (DFT) studies are discussed for the charge transfer complex GLC-TCNE, using the B3LYP with 6–311++G (d, p) basis set. The harmonic vibrational frequencies were calculated, and the scaled values have been compared with experimental FT-IR spectra. The calculated 1H and 13C NMR chemical shifts using the GIAO method showed good correlations with the experimental data. The theoretical UV–visible spectrum of the compound and the electronic properties, such as HOMO and LUMO energies, were performed using the time-dependent (TD-DFT) approach with CAM-B3LYP, employing the 6–311++G (d, p) basis set, and good agreement with the theoretical and experimental UV–visible data was found.
Atakan, B.,Jacobs, A.,Wahl, M.,Weller, R.,Wolfrum, J.
, p. 449 - 453 (1989)
Gartaganis,Winkler
, p. 1457,1461 (1956)
Temperature Dependence of the Reaction of Nitrogen Atoms with Methyl Radicals
Marston, George,Nesbitt, Fred L.,Nava, David F.,Payne, Walter A.,Stief, Louis J.
, p. 5769 - 5774 (1989)
The discharge-flow mass spectrometry technique has been used to measure the kinetics of the reaction N + CH3 -> products over the temperature range 200-423 K.The results are as follows (10-11 cm3 s-1): k1(200 K)
Surface chemistry of CN bond formation from carbon and nitrogen atoms on Pt(111)
Herceg, Eldad,Trenary, Michael
, p. 17560 - 17566 (2005)
The mechanism of CN bond formation from CH3 and NH3 fragments adsorbed on Pt(111) was investigated with reflection absorption infrared spectroscopy (RAIRS), temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The surface chemistry of carbon-nitrogen coupling is of fundamental importance to catalytic processes such as the industrial-scale synthesis of HCN from CH4 and NH3 over Pt. Since neither CH4 nor NH3 thermally dissociate on Pt(111) under ultrahigh vacuum (UHV) conditions, the relevant surface intermediates were generated through the thermal decomposition of CH 3I and the electron-induced dissociation of NH3. The presence of surface CN is detected with TPD through HCN desorption as well as with RAIRS through the appearance of the vibrational features characteristic of the aminocarbyne (CNH2) species, which is formed upon hydrogenation of surface CN at 300 K. The RAIRS results show that HCN desorption at a??500 K is kinetically limited by the formation of the CN bond at this temperature. High coverages of Cads suppress CN formation, but the results are not influenced by the coadsorbed I atoms. Cyanide formation is also observed from the reaction of adsorbed N atoms and carbon produced from the dissociation of ethylene. ? 2005 American Chemical Society.
-
Garner,Matsuno
, p. 1903 (1921)
-
Herries, D. G.,Richards, F. M.
, p. 1155 - 1156 (1964)
Suarez, M. Patricia,Loeffler, Daniel G.
, p. 240 - 242 (1986)
-
Onyszchuk,Winkler
, p. 368,369 (1955)
-
The hexacyanotitanate ion: Synthesis and crystal structure of [NEt4]3[Ti(III)(CN)6]·4MeCN
Entley, William R.,Treadway, Christopher R.,Wilson, Scott R.,Girolami, Gregory S.
, p. 6251 - 6258 (1997)
The hexacyanotitanate salt, [Et4N]3[Ti(CN)6]·4MeCN, has been prepared by addition of tetraethylammonium cyanide to the titanium(III) triflate salt Ti(O3SCF3)3(MeCN)3. The orange crystalline product has been characterized by X-ray diffraction, and the d1 anion is only slightly distorted from ideal O(h) symmetry. The anion resides on a center of symmetry and is characterized by the following parameters: Ti-C = 2.195(2), 2.197(3), and 2.213(3) A?; C-N (av) = 1.141(4) A?; C-Ti-C (cis) = 88.01(9), 88.02(9), 89.02(9), and 89.78(9)°; C-Ti-C (trans) = 180°. In addition to the crystallographic study, details of the IR (ν(CN) = 2071 cm-1), EPR, and UV-vis spectra (Δ(o) = 22800 cm-1) are given. Crystal data for [Et4N]3[Ti(CN)6]·4MeCN are as follows: monoclinic, space group I2/a, a = 18.171(6) A?, b = 12.200(4) A?, c = 20.989(5) A?, β = 91.17(2)°, V = 4652(2) A?3, Z = 4, wR2 = 0.2054 for 3831 data, 27 restraints, and 318 parameters.
Characterization of a carbon-nitrogen network solid with NMR and high field EPR
Rovnyak, David,Baldus, Marc,Itin, Boris A.,Bennati, Marina,Stevens, Andrew,Griffin, Robert G.
, p. 9817 - 9822 (2000)
Considerable attention has been focused on developing a synthetic route to a carbon-nitrogen material with mechanical and thermal properties comparable or superior to those of diamond. To date, no substance with the desired C3N4 stoichiometry in a silicon-nitride crystal lattice has been reported. One of the principal difficulties in the pursuit of ultrahard carbon-nitrogen (CN) solids is the characterization of amorphous CN samples. We describe a solid-state NMR study of a paracyanogen-like solid utilizing 13C-15N adiabatic-passage Hartmann-Hahn cross-polarization (APHH-CP) to perform dipolar filtering and show that this method is well-suited for recoupling 13C-15N in network solids. In addition, high-frequency electron paramagnetic resonance (EPR) indicates a density of electron spins of approximately 1 × 1017 e-/cm3. We conclude by discussing how NMR and EPR data may be useful for optimizing CN-polymer samples as potential precursors for ultrahard carbon nitrogen solids.
-
Fosse,Hieulle
, (1922)
-
Hasenberg, D.,Schmidt, L. D.
, p. 441 - 453 (1987)
Bassett, H.,Corbet, A. S.
, p. 1358 - 1358 (1924)
Facile Synthesis of the Dicyanophosphide Anion via Electrochemical Activation of White Phosphorus: An Avenue to Organophosphorus Compounds
Liu, Liu Leo,Mei, Yanbo,Yan, Zeen
supporting information, p. 1517 - 1522 (2022/02/01)
Organophosphorus compounds (OPCs) have gained tremendous interest in the past decades due to their wide applications ranging from synthetic chemistry to materials and biological sciences. We describe herein a practical and versatile approach for the trans
Large Faraday Rotation in Optical-Quality Phthalocyanine and Porphyrin Thin Films
Nelson, Zachary,Delage-Laurin, Leo,Peeks, Martin D.,Swager, Timothy M.
supporting information, p. 7096 - 7103 (2021/05/29)
The magneto-optical phenomenon known as Faraday rotation involves the rotation of plane-polarized light as it passes through an optical medium in the presence of an external magnetic field oriented parallel to the direction of light propagation. Faraday rotators find applications in optical isolators and magnetic-field imaging technologies. In recent years, organic thin films comprised of polymeric and small-molecule chromophores have demonstrated Verdet constants, which measure the magnitude of rotation at a given magnetic field strength and material thickness, that exceed those found in conventional inorganic crystals. We report herein the thin-film magnetic circular birefringence (MCB) spectra and maximum Verdet constants of several commercially available and newly synthesized phthalocyanine and porphyrin derivatives. Five of these species achieved maximum Verdet constant magnitudes greater than 105 deg T-1 m-1 at wavelengths between 530 and 800 nm. Notably, a newly reported zinc(II) phthalocyanine derivative (ZnPc-OT) reached a Verdet constant of -33 × 104 deg T-1 m-1 at 800 nm, which is among the largest reported for an organic material, especially for an optical-quality thin film. The MCB spectra are consistent with resonance-enhanced Faraday rotation in the region of the Q-band electronic transition common to porphyrin and phthalocyanine derivatives, and the Faraday A-term describes the electronic origin of the magneto-optical activity. Overall, we demonstrate that phthalocyanines and porphyrins are a class of rationally designed magneto-optical materials suitable for applications demanding large Verdet constants and high optical quality.
Trapping of Br?nsted acids with a phosphorus-centered biradicaloid - synthesis of hydrogen pseudohalide addition products
Beer, Henrik,Bl?sing, Kevin,Bresien, Jonas,Chojetzki, Lukas,Schulz, Axel,Stoer, Philip,Villinger, Alexander
supporting information, p. 13655 - 13662 (2020/10/27)
The trapping of classical hydrogen pseudohalides (HX, X = pseudohalogen = CN, N3, NCO, NCS, and PCO) utilizing a phosphorus-centered cyclic biradicaloid, [P(μ-NTer)]2, is reported. These formal Br?nsted acids were generatedin situas gases and passed over the trapping reagent, the biradicaloid [P(μ-NTer)]2, leading to the formation of the addition product [HP(μ-NTer)2PX] (successful for X = CN, N3, and NCO). In addition to this direct addition reaction, a two-step procedure was also applied because we failed in isolating HPCO and HNCS addition products. This two-step process comprises the generation and isolation of the highly reactive [HP(μ-NTer)2PX]+cation as a [B(C6F5)4]?salt, followed by salt metathesis with salts such as [cat]X (cat = PPh4,n-Bu3NMe), which also gives the desired [HP(μ-NTer)2PX] product, with the exception of the reaction with the PCO?salt. In this case, proton migration was observed, finally affording the formation of a [3.1.1]-hetero-propellane-type cage compound, an OC(H)P isomer of a HPCO adduct. All discussed species were fully characterized.
