CAUTION: The reaction and distillation should be conducted behind a safety shield. Precautions for handling toxic cyanides should be observed.
To a three-necked flask equipped with a condenser and ground glass stirrer (or Hershberg stirrer) is added 116 gm (0.75 mole) of ethyl iodide and 100 gm (0.75 mole) of silver cyanide. The mixture is refluxed for 2 hr, the stirrer blade raised, the mixture cooled, filtered (see Note a), the solid washed with ether, dried, and 260 gm of a 50% solution of potassium cyanide (2.0 moles) added. The reaction mixture is distilled to afford a mixture of isonitrile and water (see Note b). The crude isonitrile 49.5- 52.3 gm (90-95%) is separated after being salted out of the water. The isonitrile is washed twice with 24-ml portions of ice-cold saturated sodium chloride solution, dried over magnesium sulfate, and fractionally distilled, to afford 25.9-30.3 gm (47-55%), b.p. 77-79°C (760 mm Hg).