Pyridine is a basic, heterocyclic organic compound similar to benzene, with one CH group replaced by nitrogen. It is a flammable, water-miscible liquid with a strong, fish-like odor. Though colorless, old or impure samples may turn yellow due to polymer formation.
🏭⚗️ Synthesis
Pyridine is synthesized by condensing aldehydes, ketones, or α,β-unsaturated carbonyls with ammonia. A common method uses formaldehyde and acetaldehyde, which first form acrolein, then condense with ammonia to yield dihydropyridine, which is oxidized to pyridine. The reaction occurs in gas phase at 400–450 °C using alumina/silica catalysts. It also produces methylpyridines.
🧪 Applications
Pesticides & Pharma: Used to make herbicides (e.g., paraquat, diquat), fungicides, and antiseptics like cetylpyridinium chloride.
Lab Use: Acts as a polar, basic solvent; used in reactions like Knoevenagel condensations, esterifications, and acylations. Derivatives like DMAP are more reactive in such processes.
⚠️Safety
Pyridine is a flammable and toxic organic compound. It causes irritation to eyes, skin, and respiratory tract, and may harm internal organs with prolonged exposure. Handle only with proper protective equipment and ventilation.
