Acetonitrile: Properties, Reactions, Uses Of Acetonitrile

Acetonitrile, often abbreviated as MeCN (methyl cyanide), is a compound with the formula CH3CN and the structure H3C—C≡N. This colourless liquid is the simplest organic nitrile, and even the simpler nitrile, but the cyanide anion is not classified as organic. It occurs mainly as a by-product in the production of acrylonitrile. Cyanomethane is a clear, colourless liquid with an aromatic odour. It has a flash point of 42°F and is less dense than water. The vapour is denser than air. Methane carbonitrile has a sweet taste and is readily soluble in water. It acts as a polar aprotic solvent and is an aliphatic nitrile.

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This Story also Contains

1. Properties Of Acetonitrile
2. Reactions Of Acetonitrile
3. Uses Of Acetonitrile
4. Health Hazards Of Acetonitrile
5. Structure Of Acetonitrile
6. Manufacture Of Acetonitrile

Properties Of Acetonitrile

• The molar mass of acetonitrile is 41.053 gmol-1.

• It is a colourless liquid.

• Has a faint, distinctive, fruity odour.

• The density of acetonitrile is 0.786 g/cm3 at 25 °C.

• The boiling point of acetonitrile is 81.3-82.1 °C, melting point of acetonitrile is -46 to -44 °C.

• Miscible with water.

• Acetonitrile has a vapour pressure of 9.71 kPa.

• Acetonitrile has an acidity of 25.

• The magnetic susceptibility of acetonitrile is -28.0×10−6 cm3/mol.

• Its refractive index is 1.344.

Reactions Of Acetonitrile

1. Reaction with Concentrated Hydrochloric Acid

Partial hydrolysis of acetonitrile in cold concentrated hydrochloric acid forms the acetamide product. Upon complete hydrolysis, it forms a carboxylic acid.

2.Reaction with phenylmagnesium bromide

Nitrile reacts with a Grignard reagent to form a ketone. Nitriles i.e. RC≡N, react with Grignard or organolithium reagents to form ketones. Highly nucleophilic organometallic reagents add to C≡N bonds in a manner similar to aldehydes and ketones.

Uses Of Acetonitrile

• Acetonitrile is used as a solvent for hydrocarbon extraction.

• It is used for the separation of fatty acids from vegetable oils.

• It is used in the manufacture of perfumes.

• It is widely used in the manufacture of synthetic pharmaceuticals.

• It is used in the manufacture of rubber.

• Copper is refined and extracted using this process.

• It is used as a solvent in electrochemical cells.

• Chemists use it as a solvent in chemical reactions and chromatography.

• It is widely used in battery applications due to its relatively high dielectric constant, and it also has the ability to dissolve electrolytes.

• Acetonitrile is also used in high-performance liquid chromatography.

• Acetonitrile was used in formulating a nail polish remover.

• Acetonitrile is used in the manufacture of DNA oligonucleotides, in the pharmaceutical sector, and as a solvent in photographic films.

Health Hazards Of Acetonitrile

This compound is toxic if absorbed through the skin. It is highly flammable and releases toxic gases and vapours in the event of fire. A mixture of cyanomethane and air or steam is explosive. If it comes into contact with strong oxidants, it may explode. It can also explode when heated due to increased pressure. Severe exposure can cause a rash, delirium, numbness, irritation, confusion, and convulsions.

Structure Of Acetonitrile

Acetonitrile is classified as a nitrile based on its functional groups. According to organic chemistry, a nitrile is defined as a carbon atom containing a triple bond to a nitrogen atom. Acetonitrile is the simplest organic nitrile, containing a carbon-nitrogen triple bond.

Manufacture Of Acetonitrile

It is obtained as a by-product of the manufacture of acrylonitrile. It can also be synthesised by hydrogenating a mixture of carbon monoxide or dehydrating acetamide and ammonia. The present invention discloses a two-step process for producing high-purity acetonitrile from acetic acid and ammonia that consists of the following two steps: The first step is neutralising acetic acid and ammonia to form ammonium acetate. In the second step, this mixture was preheated and introduced into a fixed-bed reactor packed with an alumina catalyst to produce acetonitrile-containing mixed gas, and after continuous purification of this gas, pure acetonitrile was obtained.