Chemical Properties
Colorless to yellow liquid. Iodoethane is a stable chemical substance. It is incompatible with strong bases, magnesium, and strong oxidising agents and gets discoloured when exposed to light, moisture, and air.
Purification Methods
Drying the iodide with P2O5 is unsatisfactory, and with CaCl2 it is incomplete. It is probably best to dry it with sodium wire and distil [Hammond et al. J Am Chem Soc 82 704 1960]. Exposure of ethyl iodide to light leads to rapid decomposition, with the liberation of iodine. Free iodine can be removed by shaking with several portions of dilute aqueous Na2S2O3 (until the colour is discharged), followed by washing with water, drying (with CaCl2, then sodium), and distilling. The distilled ethyl iodide is stored, over mercury, in a dark bottle away from direct sunlight. Other purification procedures include passage through a 60cm column of silica gel, followed by distillation, and treatment with elemental bromine, extraction of free halogen with Na2S2O3 solution, followed by washing with water, drying and distilling. Free iodine and HI have also been removed by direct distillation through a LeBel-Henninger column containing copper turnings. Purification by shaking with alkaline solutions, and storage over silver, are reported to be unsatisfactory. [Beilstein 1 IV 163.]
