The synthesis of an aromatic polyamide

Caution Carry out all procedures in a we 11-ventilated fume-cupboard, wear appropriate disposable gloves, a lab-coat, and safety glasses. 

Apparatus forfiltration, Buchnerfunnel and flask, water pump 

Hotplate/magnetic stirrer and oil-bath Thermometer and ground-glass adapter Vacuum oven 

Preparation. In an Erlenmeyer flask (1 L) p-phenylenediamine (100 g) is dissolved in hot water (300 ml) containing sodium dithionate (3.5 g) and the solution is then filtered and cooled in an ice-bath to crystallize. The white crystals formed are collected by filtration at the water pump, dried in air and then in a vacuum desiccator over phosphorous pentoxide. Isophthalic acid is purified by recrystallization from hot methanol the hot solution is filtered and then cooled in an ice-salt-bath, the white crystals formed are collected by filtration at the water pump and dried in a vacuum oven. 

In a two-necked round-bottomed flask (250 mL), equipped with a thermometer, condenser, and a magnetic stirrer is placed p-phenylenediamine (2.16 g, 20 mmol) and isophthalic acid (3.32 g, 20 mmol). To this mixture NMP, 60 mL and pyridine (40 mL) containing lithium chloride (1.4 g, 4% by weight) are added and then triphenyl phosphite (10.5 mL, 40 mmol) is added and the mixture is stirred to give a dark-coloured solution. 

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