Azine is an organic compound with the chemical formula C5H5N. It is a colorless, soluble, volatile liquid with a distinctive, unpleasant smell. Azine is practically insoluble in water but very soluble in organic solvents due to its non-polar nature. It melts at -41.6°C and boils at 115.2°C.
Azine was first isolated in 1849 from coal tar and named after the Latin word “pyr” meaning fire due to its combustion properties. Commercially, it is produced by either coal carbonization or petroleum refining. Azine finds wide application as a precursor to agrochemicals, pharmaceuticals, vitamins, and as a solvent.
Chemical Properties and Reactions
Azine has high chemical stability and Pyridine can withstand reaction conditions like high temperature, alkaline medium and oxidizing agents. It displays basicity due to the presence of the –N lone pair of electrons, making it a weak base. Azine has a pKa of 5.25 and readily undergoes protonation to form pyridinium cation.
Due to the polarity of the pyridinium ion, Azine undergoes electrophilic aromatic substitution easily. Common electrophiles include alkyl halides, acid chlorides, and acyl chlorides. The substitution occurs at the para and ortho positions of the heterocyclic ring relative to the nitrogen atom. This allows for various derivatives to be synthesized.
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