Potassium cyanate is an inorganic compound

Inorganic compound

Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 with the formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 KOCN (sometimes denoted KCNO). It is a colourless solid. It is used to prepare many other compounds including useful herbicide

Herbicide

Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...

. Worldwide production of the potassium and sodium salts was 20,000 tons in 2006.

Structure and bonding

Cyanate is isoelectronic with carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 azide

Azide

Azide is the anion with the formula N3−. It is the conjugate base of hydrazoic acid. N3− is a linear anion that is isoelectronic with CO2 and N2O. Per valence bond theory, azide can be described by several resonance structures, an important one being N−=N+=N−...

, being linear. The C-N distance is 121 nm, about 60 nm longer than for cyanide

Cyanide

A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....

. Potassium cyanate is isostructural with potassium azide

Potassium azide

Potassium azide is the chemical compound having the formula . It is the potassium salt of hydrazoic acid, and crystallizes in a tetragonal structure. Upon heating or irradiation with ultraviolet light, it decomposes into potassium metal and nitrogen gas...

.

Uses

For most applications, the potassium and sodium salts can be used interchangeably. Potassium cyanate is often preferred to the sodium salt, which is less soluble in water and less readily available in pure form.

Potassium cyanate is used as a basic raw material for various organic syntheses, including, urea

Urea

Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 derivatives, semicarbazide

Semicarbazide

In organic chemistry, semicarbazide is a derivative of urea, where NH2 on one side has been replaced with H2NNH2 hydrazine, yielding H2NNHCNH2.Semicarbazide is used as a detection reagent on thin layer chromatography...

s, carbamate

Carbamate

Carbamates are organic compounds derived from carbamic acid . A carbamate group, carbamate ester, and carbamic acids are functional groups that are inter-related structurally and often are interconverted chemically. Carbamate esters are also called urethanes.-Synthesis:Carbamic acids are derived...

s and isocyanate

Isocyanate

Isocyanate is the functional group of elements –N=C=O , not to be confused with the cyanate functional group which is arranged as –O–C≡N or with isocyanide, R-N≡C. Any organic compound which contains an isocyanate group may also be referred to in brief as an isocyanate. An isocyanate may have more...

s. For example, it is used to prepare the drug hydroxyurea. It is also used for the heat treatment

Heat treatment

Heat treating is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass...

 of metals (e.g., Ferritic nitrocarburizing

Ferritic nitrocarburizing

Ferritic nitrocarburizing is a range of case hardening processes that diffuse nitrogen and carbon into ferrous metals at sub-critical temperatures. The processing temperature ranges from to , but usually occurs at...

).

Therapeutic Uses

Potassium Cyanate has been used to reduce the percentage of sickled erythrocytes under certain conditions and has also increased the number of deformalities. In an aqueous solution, it has prevented irreversibly the in vitro sickling of hemoglobins containing human erythrocytes during deoxygenization. Veteranarians have also found potassium cyanate useful in that the cyanate salts and isocyanates can treat parasite diseases in both birds and mammals.

Preparation and reactions

KOCN is prepared by urea

Urea

Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 with potassium carbonate

Potassium carbonate

Potassium carbonate is a white salt, soluble in water , which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid...

 at 400 °C:

2 OC(NH₂)₂ + K₂CO₃ → 2 KOCN + (NH₄)₂CO₃

The reaction produces a liquid. Intermediates and impurities include biuret

Biuret

Biuret is a chemical compound with the chemical formula H2NCNHCNH2. It is the result of condensation of two molecules of urea and is a problematic impurity in urea-based fertilizers. This white solid is soluble in hot water....

, cyanuric acid

Cyanuric acid

Cyanuric acid or 1,3,5-triazine-2,4,6-triol is a chemical compound with the formula 3. Like many industrially useful chemicals, this triazine has many synonyms. This white, odorless solid finds use as a precursor or a component of bleaches, disinfectants, and herbicides...

, and potassium allophanate (KO₂CNHC(O)NH₂), as well as unreacted starting urea, but these species are unstable at 400 °C.

Protonation gives a 97:3 mixture (at room temperature) of two tautomer

Tautomer

Tautomers are isomers of organic compounds that readily interconvert by a chemical reaction called tautomerization. This reaction commonly results in the formal migration of a hydrogen atom or proton, accompanied by a switch of a single bond and adjacent double bond...

s, HNCO and NCOH. The more abundant tautomer trimerizes to give cyanuric acid.

Properties

Potassium carbonate crystals are destroyed by the melting process so that the urea can react with almost all potassium ions to convert to potassium cyanate at a higher rate than when in the form of a salt. This makes it easier to reach higher purities above 95%. It can also be made by oxidizing potassium cyanide at a high temperature in the presence of oxygen or easily reduced oxides, such as lead, tin , or manganese dioxide, and in aqueoues solution by reacting with hypochlorites or hydrogen peroxide. Another way to synthesize it is to allow an alkali metal, cyanide, to react with oxygen in nickel containers under controlled conditions. It can be formed by the oxidation of ferrocyanide. Lastly, it can be made by heating potassium cyanide with lead oxide.

External links

• MSDS
• MSDS at jtbaker.com