SERWIS ELEKTRONICZNY - RADIOELEKTRYKA SOSNOWIEC POLSKA

NIEZALEŻNA DZIAŁALNOŚĆ BADAWCZO - NAUKOWA KLIKNIJ NA OPIS DOKUMENTU

WWW.RADIOELEKTRYKA.GLT.PL WWW.RADIOELEKTRYKA.PRV.PL

WWW.RADIOELEKTRYKA.EU

Threats Hydrogen cyanide in cigarettes - tobacco pipe (highly toxic)
Operation of HCN depending on the concentration of the air concentration of the HCN
[mg / dm] Effects
300 immediate death
200 died after 10 minutes
120-150 death after 0.5-1 h
20-40 weaknesses symptoms after several hours of exposure.
Chemical Hydrogen cyanide, HCN - a chemical compound made of hydrogen, carbon and nitrogen, which is colorless, volatile and highly poisonous liquid with an odor of bitter almonds. With water forms a weak hydrogen cyanide, which are known as cyanide salts.
Formula: HCN IUPAC name: formonitrile
Molar mass: 27.0253 g / mol
Boiling point: 25.6 ° C
Density: 687.00 kg / m³
Melting point: -13.4 ° C
Hydrogen cyanide
General Information
Molecular formula HCN
Other models H-C≡N
Molar mass 27,03 g / mol
Appearance: colorless, volatile liquid with an odor of bitter almonds.

Hydrogen cyanide, HCN - a chemical compound made of hydrogen, carbon and nitrogen, which is colorless, volatile and highly poisonous liquid with an odor of bitter almonds (which however, may be detectable by some individuals). With water forms a weak acid hydrocyanic (prussic acid), which are called cyanide salts. He found application in the synthesis and chemical analysis, and as a pesticide. During the Second World War was used as an insecticide Zyklon B to the poisoning of German prisoners of concentration camps. This includes ogólnotrujących it to chemical agents and is added to the list 3. Convention on the Prohibition of Chemical Weapons.
Occurrence In nature, hydrogen cyanide is present in bound form in heterozydach. Particularly rich are not the seeds and leaves of stone fruits, for example. Bitter almonds, peach and apricot kernels (containing amygdalin), white clover (linamarynę and lotaustralinę), wild cherry bark (prusarynę Hydrogen cyanide is also present in tobacco smoke.
Preparation of Laboratory scale reactions are Significance laboratory cyanide (or hexacyanoferrates (II), for example. Hexacyanoferrate (II) solution) with strong acids and distillation of the resulting hydrogen cyanide:
2KCN + H2SO4 + K2SO4 → 2HCN
NaCN + HCl → HCN + NaCl
K4 [Fe (CN) 6] + 6HCl → 6HCN + 4KCl + FeCI2
or by passing hydrogen sulphide vapor over solid cyanide mercury (II):
H2S + Hg (CN) 2 → 2HCN + HgS
Hydrogen cyanide can also be obtained by heating the methanol (the absence of air at a temperature of 600-950 ° C using a catalyst) and acetonitrile (at a temperature of 1100-1300 ° C) with ammonia and by thermal decomposition of formamide with elevated temperature and reduced pressure:
CH 3 OH + NH 3 → HCN + H2O + H2
CH 3 CN + NH3 + 2H2 → 2HCN
HCONH2 → HCN + H2O

Historically, industrial scale cyanide obtained industrially by acidification cyanide (e.g.. NaCN or Ca (CN) 2). Currently, there are three industrial processes for obtaining hydrogen cyanide - Andrussow process, BMA process and the Shawinigan process. However, with approx. 25% of the world production of hydrogen cyanide corresponds to the Sohio process wherein HCN is formed as a byproduct of the preparation of acrylonitrile from propylene and ammonia. The most important industrial production of hydrogen cyanide by the process in which the exothermic reaction of methane with ammonia, the presence of oxygen from the air:
CH4 + NH3 + 1,5O2 → HCN + 3H2O ΔH = -474 kJ / mol [2]
The reaction is catalyzed by platinum or its alloys with rhodium and iridium (usually a catalyst is used in the form of a grid of an alloy of 90% platinum and 10% rhodium). The process is conducted at a temperature above 1000 ° C. Strip-based reaction is purified from the excess of ammonia with an ammonium sulphate solution containing sulfuric acid. Then, hydrogen cyanide is absorbed in water (acidulated with sulfuric acid), and distilled from the solution of [24]. The advantages of this process are the long life of the catalyst, proven technology and high purity of the obtained product, however, used in the catalyst is susceptible to poisoning contamination present in the methane (higher hydrocarbons, sulfur and phosphorus), thus requiring high purity material.

Hydrogen cyanide BMA process is also produced by the BMA. Here comes to the reaction of methane with ammonia at high temperature, also making use of a platinum catalyst:
CH4 + NH 3 → HCN + 3H2 ΔH = 252 kJ / mol
Due to endotermiczność process, it is necessary to provide heat. This is done by passing the raw material through the bundle of tubes of aluminum (from the inside of the coated layer of the catalyst) in the reaction furnace, in which the reaction mixture is heated to over 1200 ° C. After leaving the tube, the gas is cooled to 300 ° C. Hydrogen cyanide is purified and secreted in the same manner as in the Andrussow Process, with its higher content of the exhaust after-reaction compared to the first trial allows to reduce the size and cost of the apparatus. The process involves reacting gaseous hydrocarbons (typically propane) with ammonia in a fluidized bed coking electrically heated:
NH3 + C3H8 → 3HCN + 7H2 ΔH = 634 kJ / mol
The process takes place at a temperature above 1500 ° C and does not require a catalyst. There is also no need to use the apparatus for the absorption of ammonia since at least 85% is consumed. An important disadvantage is, however, large energy consumption, thus limiting the use of this process to the areas where it is cheap.

Properties Hydrogen cyanide is a colorless liquid with a strong odor of bitter almonds - perceptibility threshold is 0,002-0,005 mg / dm air. Some people can not sense it, however. It shows high volatility. Freely miscible with water and alcohols. On the air burns a blue flame. The vapor form explosive mixtures with air (in the range 6-41% by volume. Cyjanowodory acid is very weak (pKa = 9.36). Depending on the conditions can polymerize - oligomers thereof include aminomalononitryl (trimer), and diaminomalononitryl (tetramer). Hydrogen cyanide oxidized during heating (300-650 ° C) in air to form a cyanic acid and minor amounts of cyan:
HCN + O2 → 2HOCN
4HCN + O2 → 2 (CN) 2 + 2H2O
The reaction is catalyzed by gold and silver, wherein the silver catalysts lead to the formation of cyanogen.
In the reactions with the principles creates the appropriate cyanide:
HCN + NaOH → NaCN + H2O
2HCN + Ca (OH) 2 → Ca (CN) 2 + H2O
2HCN + Na2CO3 → 2NaCN + H2O + CO2 [27]
Undergoes an addition reaction to the carbonyl group of aldehydes and ketones most of the rise cyanohydrins:
RCOR '+ HCN → RC (OH) (CN) R'
This reaction has industrial importance, and due to its low speed, it is usually performed using weak bases (eg. Potassium cyanide) in the role of a catalyst.

The application is used for disinfection and pest control rooms, for example. Ships or warehouses. The salt form is used in the metallurgical industry, water treatment and classical chemical analysis (CN- ions strongly complexing transition metals). Hydrogen cyanide is used primarily in the production of methyl methacrylate in the plastics industry and in the synthesis for the preparation of potassium cyanide and sodium adiponitrile, methionine, cyanuric chloride, cyanogen, nitrilotriacetic acid and certain of triazine pesticides. It is also used to carry out death penalties in the gas chamber. During the Second World War was used by the Germans under the trade name Zyklon B in mass executions in concentration camps. During World War I attempted to use it as a toxic chemical agent, but without any particular success. Studies on its use for this purpose were conducted in 1915 and by the end of this year, was placed in a mixture of chloroform, arsenic trichloride and tin chloride (IV) in the French missiles No. 4. It was first used in combat operations in July 1916 year. His military markings at the time were Forestite and CK. It is now included on list 3. Convention on the Prohibition of Chemical Weapons. It is highly toxic (lethal dose for a human weighing about 60 kg is approx. 50-60 mg). Hydrogen cyanide is readily absorbed through the lungs, skin and gastrointestinal tract where dissociates and the resulting cyanide ion CN- easily associated with Fe3 + ions and strongly inhibits the enzyme cytochrome oxidase. Has the effect of blocking the transfer of oxygen from the oxyhemoglobin tissues (venous cyanide poisoning has a bright red color, which is normally characteristic of arterial blood). Blocking respiratory enzymes is reversible, which is used in the treatment of victims - CN- have significant affinity for methemoglobin, so poisoned administered isoamyl nitrite or sodium nitrite, to cause methemoglobinemia and restoring transportation of oxygen to the cells.