Pyridine - Preparation and Properties

This Presentation describes the preparation and properties of Pyridine - Heterocyclic Compound with Molecular Formula C5H5N.

1. PYRIDINE Dr. J.FELICITA FLORENCE ASSISTANT PROFESSOR

2. PYRIDINE Pyridine is a basic heterocyclic organic compound with the molecular formula C 5 H 5 N.

3. PROPERTIES I t is used in agrochemicals, pharmaceuticals and vitamins. It is structurally related to benzene with one methine group replaced by nitrogen atom. Pyridine is a highly flammable ,weakly alkaline, water miscible liquid with a defensive unpleasant smell. It is colorless but older or impure samples can appear yellow.

4. Pyridine was first isolated by Anderson in 1851 from bone oil

5. PREPARATION OF PYRIDINE

6. ISOLATION OF PYRIDINE FROM COAL TAR The light oil fraction of coal tar contains besides pyridine and alkyl pyridines, aromatic hydrocarbons. It occurs to the extend of 0.1% in coal tar from which it is obtained commercially.

7. Pyridine is obtained by passing a mixture of acetylene and hydrogen cyanide through a red hot tube 2. BONNEMANN CYCLIZATION Acetylene Acetylene

8. 3. Pyridine is prepared by heating with Pentamethylene diamine Hydrochloride and then oxidising the product with Piperidine and Concentrated Sulphuric acid at 300°C Piperidine

9. The first step of the synthesis is the condensation of 2 moles of 3-dicarbonyl compound with 1 mole of an aldehyde and 1 mole of ammonium . The dihydropyridine derivative obtained from the first step is on oxidation with Nitric acid/FeCl3 yields pyridine.

10. 5. A laboratory preparation of pyridine includes distillation of nicotinic acid with soda lime (NAOH+CaO)

11. REFERENCES 1 . Organic Chemistry by D.S. Tewari. 2. Modern Organic Chemistry by M.K.Jain and S.C. Sharma.