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Tolunitriles

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Identification
Molecular formula
C8H7N
CAS number
620-22-4 (2-methylbenzonitrile), 620-21-1 (3-methylbenzonitrile), 104-85-8 (4-methylbenzonitrile)
IUPAC name
2-methylbenzonitrile;3-methylbenzonitrile;4-methylbenzonitrile
State
State

Tolunitriles are liquids at room temperature. They are often used in organic synthesis and can be distilled under reduced pressure to yield purer samples.

Melting point (Celsius)
1.00
Melting point (Kelvin)
274.15
Boiling point (Celsius)
218.00
Boiling point (Kelvin)
491.15
General information
Molecular weight
117.15g/mol
Molar mass
117.1500g/mol
Density
1.0100g/cm3
Appearence

The tolunitriles are aromatic nitriles that appear as colorless liquids. Their appearance can vary slightly due to impurities, but they are typically clear to pale yellow.

Comment on solubility

Solubility Characteristics of Methylbenzonitriles

The solubility of the three isomers of methylbenzonitrile (2-methylbenzonitrile, 3-methylbenzonitrile, and 4-methylbenzonitrile) exhibits intriguing patterns influenced by their molecular structure and configuration. Here’s a detailed look:

  • 2-Methylbenzonitrile: Known to have moderate solubility in polar solvents such as water and ethanol. Its solubility is often attributed to the presence of the nitrile group that can form hydrogen bonds with water molecules.
  • 3-Methylbenzonitrile: This isomer tends to show slightly lower solubility compared to its ortho counterpart, primarily due to steric hindrance that impacts its ability to solvate effectively.
  • 4-Methylbenzonitrile: Exhibits higher solubility in organic solvents while being less soluble in water. The para configuration allows for a more efficient packing in non-polar environments, enhancing interactions with organic solvents.

In summary, the solubility of these compounds can be summarized as follows:

  1. Polar solvents: 2-methylbenzonitrile > 3-methylbenzonitrile > 4-methylbenzonitrile
  2. Non-polar solvents: 4-methylbenzonitrile > 3-methylbenzonitrile ≈ 2-methylbenzonitrile

It is vital to note that the solubility can also be influenced by temperature and pH of the solvent. Understanding these solubility dynamics is essential for applications in organic synthesis and pharmaceuticals.

Interesting facts

Interesting Facts about 2-Methylbenzonitrile

2-Methylbenzonitrile, also known as o-methylbenzonitrile, is an aromatic nitrile that features a methyl group in the ortho position to the cyano group. Here are a few compelling aspects of this compound:

  • Structure and Isomerization: With its two functional groups, the positioning of the methyl group significantly affects the compound's properties and reactivity. This compound is part of a family of isomers that includes 3-methylbenzonitrile and 4-methylbenzonitrile, each having unique characteristics.
  • Applications: 2-Methylbenzonitrile plays a crucial role in the synthesis of various pharmaceuticals and agrochemicals. Its reactivity makes it a valuable intermediate in organic synthesis.
  • Biological Significance: Certain derivatives of this compound have shown potential biological activities, such as acting as antimicrobial agents, which opens avenues for medicinal chemistry research.

Interesting Facts about 3-Methylbenzonitrile

3-Methylbenzonitrile, or m-methylbenzonitrile, is an intriguing compound with a methyl group positioned meta to the cyano group. Below are notable points regarding this compound:

  • Distinct Reactivity: The meta position influences not just the sterics but also the electronic properties compared to its ortho and para counterparts, making it interesting for chemists studying substitution reactions.
  • Synthesis: This compound can be synthesized effectively through various reaction pathways, including nucleophilic substitutions. Its formation is often associated with complex reaction mechanisms involving aromatic compounds.
  • Market Presence: 3-Methylbenzonitrile is utilized in the manufacturing of specialty chemicals. Its derivatives are pivotal in producing dyes and agrochemicals.

Interesting Facts about 4-Methylbenzonitrile

4-Methylbenzonitrile, or p-methylbenzonitrile, is characterized by its methyl group being positioned para to the cyano group. Here are some fascinating aspects of this compound:

  • Stability and Reactivity: The para position generally leads to enhanced stability of the compound due to less steric hindrance. This stability can influence its reactivity in various synthesis routes.
  • Industrial Use: This compound is frequently used as a precursor in the synthesis of Flourophores, which are key components in fluorescent labeling techniques in biological research.
  • Environmental Impact: As with many aromatic compounds, understanding the environmental behavior of 4-methylbenzonitrile is critical for assessing its safety and impact in ecological settings.

Overall, the study of methylbenzonitriles provides invaluable insights into aromatic chemistry and serves as a gateway for innovative applications in scientific and industrial fields.