synonymkCN(kcn) generally refers to potassium cyanide
Potassium cyanide is an inorganic compound, chemical formula is KCN, and it is a white crystalline powder,It is highly toxic[2]。Deliquescence in wet air and release trace hydrogen cyanide gas.Easily soluble in water, ethanol, glycerin, slightly soluble in methanol, sodium hydroxide aqueous solution, the aqueous solution is strongly alkaline, and quickly hydrolyzed.
Solubility: easily soluble in water, ethanol, glycerin, slightly soluble in methanol, sodium hydroxide aqueous solution
chemical property
1. Deterioration in air
2KCN+COtwo+HtwoO=2HCN+KtwoCOthree
2. Water solution is easy to deteriorate
KCN+HtwoO=HCN+KOH
purpose
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It has the same purpose as sodium cyanide. Compared with sodium cyanide, it has higher conductivity and fine coating. It is more suitable for use but more expensive.It is used for extracting gold and silver from ores by flotation.Heat treatment of steel, manufacturing organic nitriles.Analytical chemistry is used as a reagent.In addition, it is also used for photography, etching, lithography, etc.
Health hazard: Inhibit respiratory enzymes, causing intracellular asphyxia.Acute poisoning can be caused by inhalation, oral administration or percutaneous absorption.Sudden death can be caused by taking 50-100mg orally.The clinical manifestations of the non sudden death were divided into four stages: mucosal irritation, accelerated and deepened breathing, fatigue, headache in the prodromal stage, tongue tip and mouth numbness after oral administration;Dyspnea period includes dyspnea, elevated blood pressure, bright red skin and mucous membrane, etc;Convulsive phase: convulsion, coma, respiratory failure;During paralysis, the muscles of the whole body relax, breathing and heartbeat stop and die.Long term exposure to a small amount of cyanide causes neurasthenic syndrome, eye and upper respiratory tract irritation.May cause skin rash.
Toxicological data and environmental behavior
Toxicity:Highly toxic.
Acute toxicity:LDfifty: 6.4mg/kg (rat by mouth);8500 μ g/kg (mouse by mouth).
Pollution source:Cyanide is a highly toxic substance, and its pollution accidents often occur in the production process of electroplating, gold smelting, heat treatment, gas, coking, tanning, organic glass, benzene, toluene, xylene, photography, pesticide, etc.
Metabolism and degradation:The main metabolic pathway of free cyanide in vivo is the addition reaction with sulfur under the catalysis of thiocyanase (or β - mercaptopyruvate sulfotransferase), which turns into SCN with low toxicity (only CN-1/200 of toxicity).Then it is discharged from the body by urine, saliva, sweat, etc.
The free cyano group can also combine with cobalt containing compounds in the body, such as hydroxycobalamin, to form non-toxic cyanocobalt compounds.Therefore, hydroxycobalamin or cobalt edetate can be used clinically to rescue CN-Report of acute poisoning.
Human body to CN-It has strong detoxification function, and cyanide is a non cumulative poison.When a small amount of exogenous cyanogen root without toxic dose enters the body, it can be quickly transformed into non-toxic or low toxic substances and discharged from the body.
Cyanide is very unstable in surface water. When the pH value of water is greater than 7 and there is oxygen, it can be oxidized to form carbonate and ammonia.There are microorganisms in the surface water zone that can decompose and utilize cyanide, and can also convert cyanide into carbonate and ammonia through biological oxidation.Therefore, the self purification process of cyanide in surface water is quite rapid, but the self purification process of cyanide in water body is also affected by water temperature, water aeration degree (agitation), pH, water surface size and depth and other factors.
The soil has a strong ability to purify cyanide.In addition to the cyanide that enters the soil and escapes into the air, part of it is absorbed by plants and assimilated or oxidized in plants.It can be stored in soil and partly transformed into carbonate, ammonia and formate under the action of microorganisms.When cyanide is continuously polluted, soil microorganisms can produce appropriate microbial groups after acclimatization and absorption, which plays a huge role in the purification of cyanide.Therefore, in some areas where low concentration cyanide industrial wastewater is irrigated by sewage for a long time, the content of cyanide in the soil is almost not accumulated.
Residue and accumulation:The nature has a strong purification effect on cyanide pollution, so in general, exogenous cyanide is not easy to accumulate in the environment and the body.Only under specific conditions (accidental discharge, high concentration of continuous pollution), when the amount of cyanide pollution exceeds the purification capacity of the environment, can it remain and accumulate in the environment, thus constituting a potential hazard to people and organisms.
Migration and transformation:Cyanide exists widely in nature.There are some cyanide substances in animals and plants, and some plants such as bitter almonds, ginkgo, nuts, cassava, sorghum, etc. contain considerable amounts of cyanide glycosides.It releases free hydrogen cyanide after hydrolysis, and trace cyanide can also be detected in some ordinary grains and vegetables.
Cyanide is also commonly contained in the soil, which decreases with the increase of soil depth, and its content is 0.003-0.130mg/kg.Cyanide in natural soil mainly comes from soil humus.Humus is a kind of complex organic compounds. Its core is polymerized from polyphenols and contains a certain amount of nitrogen compounds.Under the action of soil microorganisms, cyanide and phenol can be generated, so the background content of cyanide in soil is closely related to the content of organic matter.
Because hydrogen cyanide is very volatile and most cyanide is easily soluble in water, cyanide discharged into the natural environment is easy to be leached, diluted and diffused by water (or atmosphere), with strong migration capacity.Hydrogen cyanide and simple cyanide are very unstable in surface water, and hydrogen cyanide is easy to escape into the air;Or when the pH value of water is greater than 7 and there is oxygen, it can also be oxidized to form carbonate and ammonia.Simple cyanide is easily hydrolyzed in water to form hydrogen cyanide.If the water contains inorganic acid, even the carbonic acid generated by carbon dioxide dissolved in water can accelerate this decomposition process.
Hydrogen cyanide has the smell of bitter almond, which is easy to diffuse and dissolve in water to form hydrocyanic acid;Cyanide is generally colorless crystal, which is easily deliquescent in the air and has a faint odor of hydrogen cyanide, which can make water produce almond odor.
Poisoning symptoms:Mild patients have mucous membrane irritation, numbness and numbness of lips and tongues, pain, dizziness, weakness of lower limbs, chest compression, nausea, vomiting, blood pressure rise, palpitations, asthma, etc.Severe patients have irregular breathing, gradually coma, convulsion, incontinence of urine and stool, blood pressure drop, rapid respiratory disorder and death.
Hazard characteristics:Non combustible.It will produce highly toxic cyanide gas when exposed to high heat or acid.Reacts violently with nitrate, nitrite and chlorate, which may cause explosion.When exposed to acid or air, it can absorb water and carbon dioxide and decompose highly toxic hydrogen cyanide.The aqueous solution is alkaline corrosive liquid.
For leakage treatment, gas masks and gloves must be worn, swept up and poured into a large amount of water.Add excessive sodium hypochlorite or bleaching powder, place it for 24 hours, confirm that all cyanide is decomposed, dilute it and put it into the wastewater system.The contaminated area shall be soaked with sodium hypochlorite solution or bleaching powder for 24 hours, and then washed with a large amount of water. The washing water shall be put into the wastewater system for unified treatment.For hydrogen cyanide, the gas shall be sent to the fume hood or introduced into the sodium carbonate solution, the same amount of sodium hypochlorite shall be added, neutralized with 6mol/L sodium hydroxide solution, and the sewage shall be discharged into the wastewater system for unified treatment.
Protective measures
Respiratory system protection: When possible exposure to poisons, you must wear a hood type electric air supply filter type dust respirator.The isolated respirator should be worn when it may be exposed to its dust.
Eye protection: protection has been made in respiratory system protection.
Body protection: wear one-piece adhesive tape anti-virus clothing.
Hand protection: wear rubber gloves.
Others: Smoking, eating and drinking are prohibited at the work site.Clean thoroughly after work.The workshop shall be equipped with first-aid equipment and medicines.Store the clothes contaminated by poisons separately and use them after washing.Operators shall learn to save themselves and each other.
First aid measures
Skin contact: Take off contaminated clothes immediately, wash thoroughly with flowing clean water or 5% sodium thiosulfate solution for at least 20 minutes, and seek medical advice.[1]
Eye contact: immediately lift the eyelids, thoroughly flush with a large amount of flowing water or physiological saline for at least 15 minutes, and then seek medical advice.
Inhalation: quickly leave the site to a place with fresh air.Keep the respiratory tract unobstructed.If breathing is difficult, give oxygen.When breathing and heartbeat stop, perform artificial respiration (not mouth to mouth) and external chest compression immediately.Inhale isoamyl nitrite and seek medical advice.
Ingestion: drink enough warm water, induce vomiting, wash stomach with 1:5000 potassium permanganate or 5% sodium thiosulfate solution, and seek medical advice.
Fire extinguishing method: firefighters must wear special protective clothing.
Extinguishing agent: dry powder, sand, carbon dioxide and acid-base extinguishing agent are prohibited.
