Potassium cyanate

White, crystalline powder

Colorless crystals

Tetragonal crystals

Very slightly sol in alcohol

In water, 6.3X10+5 mg/L @ 10 °C

When heated to decomposition it emits toxic fumes of /hydrogen cyanide and dipotassium oxide/.

Decomposes in hot water. /from table/

Large Crystals

Colorless or white solid; [HSDB] White crystalline solid; [MSDSonline]

... /Unstable/ in presence of moisture ...

Slowly hydrolyzed to ammonia and potassium bicarbonate.

Decomposes at 700-900 °C

Decomposes in hot water

Warning

H302: Harmful if swallowed [Warning Acute toxicity, oral]

P264, P270, P301+P317, P330, and P501 (click each P-code to see the statement)

Warning

H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]

P264, P264+P265, P270, P273, P280, P301+P317, P305+P351+P338, P330, P337+P317, and P501 (click each P-code to see the statement)

Chemical: Cyanic acid, potassium salt

Cyanic acid, potassium salt (1:1) is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Cyanic acid, potassium salt (1:1) are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 27-04-2023 https://echa.europa.eu/registration-dossier/-/registered-dossier/10124

Potassium cyanate: Does not have an individual approval but may be used under an appropriate group standard

Acute Tox. 4 (100%)

Acute toxicity - category 4

Acute toxicity (Oral) - Category 4

Acute Tox. 4 *

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

Do not inhale dust.

This material is considered to be moderately toxic and personnel should be provided with respiratory and skin protection when handling this compound.

The degree of hazard appears less than with cyanide and some nitriles, but care should be used to avoid inhalation of dust /or/ prolonged and repeated skin contact.

Antidotes to cyanide poisoning include hydroxocobalamin and sodium nitrite, which release the cyanide from the cytochrome system, and rhodanase, which is an enzyme occurring naturally in mammals that combines serum cyanide with thiosulfate, producing comparatively harmless thiocyanate. Oxygen therapy can also be administered. (L97)

Exposure to high levels of cyanide for a short time harms the brain and heart and can even cause coma, seizures, apnea, cardiac arrest and death. Chronic inhalation of cyanide causes breathing difficulties, chest pain, vomiting, blood changes, headaches, and enlargement of the thyroid gland. Skin contact with cyanide salts can irritate and produce sores. (L96, L97)

LC50 Oncorhynchus mykiss (Rainbow trout, donaldson trout, fingerlings) 24.3 mg/L/96 hr (95% confidence interval: 16.8-31.8 mg/L); static

LC50 Oncorhynchus mykiss (Rainbow trout, donaldson trout, 0.4-1.3 g) 34.9 mg/L/96 hr; static

Organic nitriles decompose into cyanide ions both in vivo and in vitro. Consequently the primary mechanism of toxicity for organic nitriles is their production of toxic cyanide ions or hydrogen cyanide. Cyanide is an inhibitor of cytochrome c oxidase in the fourth complex of the electron transport chain (found in the membrane of the mitochondria of eukaryotic cells). It complexes with the ferric iron atom in this enzyme. The binding of cyanide to this cytochrome prevents transport of electrons from cytochrome c oxidase to oxygen. As a result, the electron transport chain is disrupted and the cell can no longer aerobically produce ATP for energy. Tissues that mainly depend on aerobic respiration, such as the central nervous system and the heart, are particularly affected. Cyanide is also known produce some of its toxic effects by binding to catalase, glutathione peroxidase, methemoglobin, hydroxocobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, succinic dehydrogenase, and Cu/Zn superoxide dismutase. Cyanide binds to the ferric ion of methemoglobin to form inactive cyanmethemoglobin. (L97)

/HUMAN EXPOSURE STUDIES/ Two patients developed bilateral subcapsular cataracts while receiving oral sodium cyanate 30-35 mg/kg/day. In one of the patients, lens opacities regressed spontaneously after cyanate therapy was discontinued. /sodium cyanate/

/HUMAN EXPOSURE STUDIES/ Two patients with sickle-cell disease who were receiving sodium cyanate for 440 and 600 days respectively in doses of up to 44 and 41 mg/kg/day had polyneuropathy confirmed by physical exam, quantitative sensory evaluation, nerve conduction test, electromyography and neural biopsy. /Sodium cyanate/

/SIGNS AND SYMPTOMS/ Highly irritating to eyes, skin, and mucous membranes. /Cyanic acid/

/LABORATORY ANIMALS: Acute Exposure/ Mice given lethal doses exhibited tremor, hyper-reactivity, extensor rigidity and tonic-clonic convulsions. ... Death appeared to be due to respiratory arrest during tonic phase. /cyanates/

/LABORATORY ANIMALS: Acute Exposure/ Dogs given 400 mg/kg ip show severe or fatal symptoms (vomiting, defecation, urination, lacrimation, salivation, rapid respiration, tremors, and convulsions).

/LABORATORY ANIMALS: Acute Exposure/ ...Fifteen dogs were given sodium cyanate at doses of 30 to 170 mg/kg/day, 5 days/wk. Fourteen developed cataracts which were generally posterior and subcapsular. Five animals developed corneal lesions. Cyanate-treated rats and monkeys did not develop lesions

/LABORATORY ANIMALS: Acute Exposure/ ...Parietal peritoneum from rats in the cyanate group showed a mild increase in the number of fibroblasts, with collagen deposits, infiltration by mononuclear cells, vascular congestion, round-shaped transformation of mesothelial cells, widening of submesothelial spaces, and abundant denudation of mesothelial cells. The visceral peritoneum from rats in the cyanate group showed collagen deposits with fibroblastic proliferation.

For more Non-Human Toxicity Excerpts (Complete) data for POTASSIUM CYANATE (8 total), please visit the HSDB record page.

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Monitor for seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patent can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Isocyanates, aliphatic thiocyanates, and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious or has severe pulmonary edema. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . Consider vasopressors if patient is hypotensive with a normal fluid volume. If signs of hypovolemia are present, administer fluid cautiously. Watch for signs of pulmonary edema ... . Treat seizures with diazepam (Valium) ... . Treat exposure to Lethane 60 Lethane 384, Thanite, methyl, ethyl, or isopropyl thiocyanates; with the cyanide antidote kit (DIRECT PHYSICIAN ORDER ONLY, refer to cyanide guideline and cyanide protocol in Section Four). Use proparacaine hydrochloride to assist eye irrigation ... . /Isocyanates, aliphatic thiocyanates, and related compounds/

The diphosphopyridine nucleotide (DPN)-specific isocitrate dehydrogenase of pig heart is totally and irreversibly inactivated by 0.05 M potassium cyanate at pH 7.4 ...In the presence of manganous ion the addition of isocitrate protects the enzyme against cyanate inactivation. ...The addition of the chelator EDTA essentially prevents protection by isocitrate and manganous ion, ...the substrate alpha-ketoglutarate and the coenzymes DPN and DPNH do not significantly affect the rate of modification of the enzymes by cyanate. Incubation of isocitrate dehydrogenase with 14C-labeled potassium cyanate leads to the incorporation of approximately 1 mol of radioactive cyanate per peptide chain concomitant with inactivation.

Not converted to cyanide in toxicologically significant amount. Indeed 72% of injected dose in mice was recovered as evolved CO2 over 24 hr. /cyanates/

Organic nitriles are converted into cyanide ions through the action of cytochrome P450 enzymes in the liver. Cyanide is rapidly absorbed and distributed throughout the body. Cyanide is mainly metabolized into thiocyanate by either rhodanese or 3-mercaptopyruvate sulfur transferase. Cyanide metabolites are excreted in the urine. (L96)

Following injection of (14)C-labeled /sodium/ cyanate to mouse, radioactive distribution was 72% broken down to CO2, 7% in urine, 7.5% as specific carbamylation of hemoglobin NH2-terminal valine, 3.3% in bones, 2.1% in muscle, and less than 3% in other organs. /Sodium cyanate/

...This study investigates the fate of potassium cyanide administered orally to rats maintained for up to 4 weeks on either a balanced diet (BD) or a diet lacking the SAAs, L-cystine and L-methionine. In both groups, there was a time-dependent increase in plasma cyanate, with exponential OCN- increases in SAA-deficient rats. A strongly positive linear relationship between blood CN- and plasma OCN- concentrations was observed in these animals.

Used to make organic chemicals and drugs; as post-emergence contact herbicide; as cotton defoliant; to treat sickle cell disease; [HSDB]

Farming (Pesticides) [Category: Industry]

For potassium cyanate (USEPA/OPP Pesticide Code: 068002) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Manufacture of organic chemicals and drugs.

Postemergence contact herbicide

...A cotton defoliant.

2023: 250,000 - <400,000 lb

(1986) No Data

The production of potassium cyanate from potassium carbonate and urea requires reaction temperatures of 400 °C or above. The product is obtained from the reactor as a liquid, which must be solidified by cooling and ground after solidification. Since the crystalline structure of the potassium carbonate is destroyed in the melting process, the urea can react with nearly all potassium ions and convert them to potassium cyanate at a much higher rate than in the case of the technical-grade sodium salt. It is ... easy to reach high purities above 95%.

Potassium cyanide is readily oxidized to potassium cyanate by heating in the presence of oxygen or easily reduced oxides, such as those of lead or tin or manganese dioxide, and in aqueous solution by reaction with hypochlorites or hydrogen peroxide.

... By reacting alkali metal cyanide with air or oxygen in nickel or monel containers under controlled conditions.

By oxidation of potassium cyanide or ferrocyanide.

Heating potassium cyanide with lead oxide

92% wettable powder

AERO CYANATE

AERO CYANATE WEEDKILLER

ALICYANATE

For more Formulations/Preparations (Complete) data for POTASSIUM CYANATE (15 total), please visit the HSDB record page.

Fabricated Metal Product Manufacturing

Cyanic acid, potassium salt (1:1): ACTIVE

Its instability in presence of moisture requires that any materials used as extenders or additives must be low in moisture content.

Cyanic acid is used in the formation of some cyanates. /Cyanic acid/

A combination fertilizer and weed killer which kills crabgrass, chick-weed, smartweed and various other plants.