Pyridine
Contents
Basics
- Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N
- It is structurally related to benzene, with one methine group (=CH−) replaced by a nitrogen atom
- It is a colorless, highly flammable, weakly alkaline, water-soluble liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless
- Older or impure samples can appear yellow.
- It is a basic industrial chemical feedstock
Synthesis
Chichibabin synthesis
Basics
- This process is carried out in a gas phase at 400–450 °C with a a transition metal salt such as cadmium(II) fluoride or manganese(II) fluoride, or cobalt and thallium compound catalyst
Inputs
- Acetaldehyde
- Formaldehyde
- Ammonia
- The catalyst
Process
- First, Acrolein is formed in a Knoevenagel condensation from the acetaldehyde and formaldehyde
- The acrolein is then condensed with acetaldehyde and ammonia to give Dihydropyridine
- This is then oxidized with a solid-state catalyst to pyridine.
Outputs
- The product consists of a mixture of pyridine, simple methylated pyridines (picolines and lutidines);
its composition depends on the catalyst used and can be adapted to the needs of the manufacturer via changing the catalyst accoordingly
