- Dissolve 37.5 g (0.25 mol) of dry sodium iodide (1) in 250 ml of dry acetone in a 500-ml flask fitted with a reflux condenser protected by a calcium chloride guard-tube, and add 30.2 g (25 ml, 0.2 mol) of l-bromo-3-methylbutane.
- A precipitate of sodium bromide soon begins to form; leave the reaction mixture at room temperature for 30 minutes, and then boil under reflux for 45 minutes to complete the reaction.
- Allow to cool and filter off the sodium bromide, washing the residue with a little acetone.
- Remove the acetone from the filtrate on a rotary evaporator, and shake the residual organic halide with 100 ml of water.
- Separate the lower dark-coloured layer and wash it twice more with 50 ml portions of water; incorporate sufficient crystals of sodium thiosulphate into the first portion of wash-water to decolourise the organic phase.
- Dry the product over anhydrous calcium sulphate, filter and distil, collecting the l-iodo-3-methylbutane at 145-147 °C. The yield is 26 g (66%).
Notes to keep in mind:
1. Dry the sodium iodide for 4 hours at 100 °C under reduced pressure (oil pump).
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