Acetonitrile (ACN) or methyl cyanide is a colorless liquid used as a solvent in various industries such as pharmaceuticals, coatings, and plastics. It is highly flammable and can cause respiratory problems if inhaled.
| IUPAC Name | Acetonitrile |
| Molecular Formula | C2H3N |
| CAS Number | 75-05-8 |
| Synonyms | Methyl cyanide, Ethanenitrile, Cyanomethane, ACN |
| InChI | InChI=1S/C2H3N/c1-2-3/h1H3 |
Acetonitrile structure
The structure of acetonitrile consists of a methyl group (-CH3) attached to a nitrile group (-C≡N). The nitrile group is a functional group that consists of a carbon triple-bonded to a nitrogen atom. The molecular structure of acetonitrile is linear, and the carbon-nitrogen triple bond gives it a high degree of polarity.
Acetonitrile boiling point
The boiling point of acetonitrile is 81.6 °C (178.9 °F) at atmospheric pressure. This means that acetonitrile boils at a relatively low temperature, making it a useful solvent in various industrial processes. Its low boiling point is due to its weak intermolecular forces, which require less energy to overcome when transitioning from a liquid to a gas.
Acetonitrile molar mass
Acetonitrile has a molar mass of 41.05 g/mol. This means that one mole of acetonitrile contains 41.05 grams of the compound. Molar mass is a crucial property in chemical calculations and is used to determine the amount of substance in a given sample. It is calculated by summing up the atomic masses of each atom present in the compound.
Acetonitrile density g/ml
The density of acetonitrile is 0.786 g/ml at 25 °C. This means that one milliliter of acetonitrile has a mass of 0.786 grams. The density of acetonitrile is important in determining the volume of the solvent required for a particular application.
Acetonitrile melting point
The melting point of acetonitrile is −45.7 °C (−50.3 °F). This means that acetonitrile is a liquid at room temperature and must be stored in a cool, dry place to prevent evaporation. The low melting point of acetonitrile is again attributed to its weak intermolecular forces.
Acetonitrile molecular weight
Acetonitrile has a molecular weight of 41.05 g/mol. Molecular weight is the sum of the atomic weights of all the atoms in a molecule. It is used in stoichiometric calculations, such as determining the amount of reactants required to produce a given amount of product.
Acetonitrile formula
The chemical formula of acetonitrile is CH3CN. It is composed of one carbon atom, three hydrogen atoms, and one nitrogen atom. The molecular formula of acetonitrile is the same as its empirical formula, indicating that it exists as a simple, discrete molecule.
| Appearance | Colorless liquid |
| Specific Gravity | 0.786 g/mL at 25 °C |
| Color | Colorless |
| Odor | Mild, ether-like odor |
| Molar Mass | 41.05 g/mol |
| Density | 0.786 g/mL at 25 °C |
| Melting Point | -45.7 °C |
| Boiling Point | 81.6 °C |
| Flash Point | 2 °C |
| Water Solubility | Miscible |
| Solubility | Miscible with most organic solvents |
| Vapour Pressure | 97.8 mmHg at 25 °C |
| Vapour Density | 1.4 (air = 1) |
| pKa | 25.18 |
| pH | 7 (neutral) |
Acetonitrile Safety and Hazards
Acetonitrile (ACN) poses several safety and health hazards, making it important to handle with care. It is highly flammable and can cause fires when exposed to heat or flames. ACN is also toxic when inhaled or ingested, and prolonged exposure can cause respiratory problems, headaches, and dizziness. It is also a skin and eye irritant and can cause burns or dermatitis. Proper protective equipment, including gloves, eye protection, and respiratory protection, should be used when handling ACN. In case of exposure, affected individuals should seek medical attention immediately. Proper storage, handling, and disposal procedures should be followed to prevent accidental exposure and environmental damage.
| Hazard Symbols | Flammable, Toxic |
| Safety Description | Highly flammable liquid and vapor. Toxic if inhaled, swallowed or in contact with skin. |
| UN Ids | UN 1648 (Class 3, Packing Group II) |
| HS Code | 2926.90.90 |
| Hazard Class | 3 – Flammable liquids |
| Packing Group | II |
| Toxicity | Toxic; LD50 (oral, rat) = 250 mg/kg |
Acetonitrile Synthesis Methods
- To synthesize Acetonitrile (ACN), catalytic hydrogenation is utilized where the triple bond in acetylene is reduced to form ethylene, which is then reacted with ammonia to produce ACN. This method is highly efficient and yields high amounts of ACN.
- Another method is ammoxidation of propane, where propane is reacted with ammonia and air in the presence of a catalyst to produce ACN. This process requires high temperatures and pressures and is commonly used in industrial settings.
- Dehydration of acetamide or acetic acid is another method of producing ACN. This process involves heating acetamide or acetic acid with phosphorus pentoxide to remove a water molecule, resulting in the formation of ACN. This method is relatively simple and requires only a few steps but is less efficient than other methods.
- ACN can also be produced as a byproduct during the production of acrylonitrile, a common industrial chemical.
The synthesis of ACN involves various methods that can be tailored to suit specific industrial needs and requirements.
Acetonitrile Uses
Various industries use acetonitrile (ACN) as a versatile solvent in a variety of applications.
- ACN finds its application as a solvent for organic compounds, plastics, and dyes, and also as a stabilizer for chlorinated solvents.
- In the pharmaceutical industry, ACN is used as a solvent for manufacturing drugs like antibiotics, vitamins, insulin, and peptide hormones.
- High-performance liquid chromatography (HPLC), an important analytical technique used in the pharmaceutical industry, utilizes ACN as a mobile phase.
- The chemical industry employs ACN as a raw material for the production of acrylonitrile, which is used in the production of synthetic fibers, plastics, and resins.
- ACN is also used as a solvent in the production of adhesives, coatings, and rubber products.
- The electronics industry uses ACN as a solvent in the production of lithium-ion batteries and for the purification of semiconductors.
Overall, ACN’s versatility as a solvent makes it an essential component in various industries, from pharmaceuticals to electronics, contributing to the development of new technologies and products.
Questions:
Q: Is acetonitrile polar?
A: Yes, acetonitrile is a polar solvent due to the presence of a polar carbon-nitrogen triple bond and a polar C-H bond.
Q: How many carbon atoms are in 2.00 ml of acetonitrile (ch3cn) ? (density = 0.786 g/ml)
A: To calculate the number of carbon atoms in 2.00 ml of ACN, we first need to calculate the mass of 2.00 ml of ACN using the density given. Mass = density x volume = 0.786 g/ml x 2.00 ml = 1.572 g. The molar mass of ACN is 41.05 g/mol, which means that 1 mole of ACN contains 2 moles of carbon atoms. Therefore, the number of carbon atoms in 1.572 g of ACN is (2 moles x 1.572 g) / 41.05 g/mol = 0.0770 moles. Since there are 6.022 x 10^23 molecules in 1 mole, the number of carbon atoms in 1.572 g of ACN is (0.0770 moles x 6.022 x 10^23 molecules/mol) x 1 carbon atom/1 molecule = 4.65 x 10^22 carbon atoms. Therefore, there are approximately 4.65 x 10^22 carbon atoms in 2.00 ml of ACN.
Q: Is acetonitrile soluble in water?
A: Yes, acetonitrile is soluble in water. It has moderate solubility in water, with a solubility of approximately 200 g/L at room temperature.
Q: Can acetonitrile dissolve sulfur?
A: Yes, acetonitrile can dissolve sulfur. However, the solubility of sulfur in ACN is relatively low, with a solubility of approximately 0.5 g/100 mL at room temperature.
Q: How to filter and vacuum degas acetonitrile?
A: To filter and vacuum degas ACN, first, pass the ACN through a filter to remove any solid impurities. Then, transfer the ACN to a vacuum flask and attach the flask to a vacuum pump. Apply a vacuum to the flask and allow the ACN to boil and release any dissolved gases. The boiling point of ACN is approximately 82°C, so the flask should be heated to this temperature to ensure the complete removal of any dissolved gases. Allow the ACN to cool and release the vacuum slowly before removing the flask from the vacuum pump. The ACN is now filtered and vacuum-degassed and can be used for further applications.