Alkyl nitrites (poppers)
(Rated as: excellent)
Equip a 1-litre three-necked flask with a powerfull mechanical stirrer, a separatory funnel with stem extending to the bottom of the flask and a thermometer. Cool the flask in a mixture of ice and salt. Place a solution of 95 g (1.38 mol) of 'AnalaR' sodium nitrite in 375 ml of water in the flask and stir. When the temperature is fallen to 0 °C (or slightly below) introduce slowly from the separatory funnel a mixture of 25 ml of water, 62.5 g (34 ml) of concentrated sulphuric acid and 110 g (135 ml, 1.25 mol) of pentan-1-ol, which has previously been cooled to 0°C. The rate of addition must be controlled so that the temperature is maintained at +/- 1 °C; the addition takes 45 - 60 minutes. Allow the mixture to stand for 1.5 hours and then filter from the precipitated sodium sulphate. Separate the upper yellow pentyl nitrite layer, wash it with a solution containing 1 g of sodium hydrogen carbonate and 12.5 g of sodium chloride in 50 ml of water, and dry it with 5-7 g of magnesium sulphate. The resulting crude pentyl nitrite (107 g, 73 %) is satisfactory for many purposes . Upon distillation, it passes over largely at 104 °C with negligible decomposition. The B.P. under reduced pressure is 29 °C / 40 mm Hg.
Hexyl nitrite may be prepared similarly by using 95 g (1.38 mol) of 'AnalaR' sodium nitrite in 375 ml of water; a mixture of 25 ml of water, 62.5 g (34 ml) of concentrated sulphuric acid and 127.5 g (156 ml, 1.25 mol of hexan-1-ol). The yield of crude product is 124 g (76 %). B.P. 129 - 130.5 °C or 52 °C / 44 mm Hg.
For butyl nitrite use the same quantities as for hexyl nitrite, but with 92.5 g (114 ml, 1.25mol) of butan-1-ol replacing the hexan-1-ol. The yield of crude product is 110 g (85 %). Butyl nitrite boils at 76.5 - 77.5 °C at atmospheric pressure with slight decomposition, but distills unchanged at 27 °C / 43 mm Hg.
ref.: Vogel, 5th ed., p 413