pyridin

Pyridine, occasionally spelled pyridin in some languages, is a basic heterocyclic aromatic organic compound with the formula C5H5N. It consists of a six-membered ring containing five carbon atoms and one nitrogen atom, with aromatic electron delocalization. The molecule is a colorless liquid at room temperature with a distinctive, unpleasant odor.

It is fully miscible with water and many organic solvents. Its boiling point is about 115 °C. As a weak base, the nitrogen lone pair can be protonated to form pyridinium salts. Pyridine readily acts as a coordinating ligand in transition-metal complexes and can participate in a variety of substitution and coupling reactions in organic synthesis.

Sources and production: Pyridine occurs in trace amounts in coal tar and tobacco smoke. Industrially, it is produced on a large scale by several catalytic processes, including the dehydrogenation of piperidine and related compounds, as well as other methods that convert simple precursors into the pyridine ring.

Applications: It is widely used as a solvent and as a building block for the manufacture of agrochemicals, pharmaceuticals, and vitamins. It serves as a precursor to many heterocyclic compounds and is used in the synthesis of ligands for coordination chemistry.

Safety: Pyridine is toxic and mildly irritating to skin, eyes, and the respiratory tract. It is flammable and should be handled in a well-ventilated area with appropriate protective equipment. Environmental release should be minimized and controlled due to potential hazards to aquatic life.