To a reflux apparatus with 10.8 g of phosphorus pentoxide slowly with stirring 38.6 g of 85% phosphoric acid when the solution cools down to room temperature add 55.5 g of potassium iodide and 14.5 g of amyl alcohol, reflux the solution for 4h with stirring in an oil bath. After the reflux, cool the solution down and pour it into a separatory funnel with 50 mL of water and 80 mL of hexane, shake the mixture and discard the bottom layer, wash with 10% sodium metabisulfite solution until the layer becomes almost colorless. Dry the crude product with some anhydrous magnesium sulfate and distil over some copper powder. Store the pure product in an amber bottle with some copper powder.
Combining the phosphorus compounds
Washing the mixture with the hexane and water
Washing the organic layer with the metabisulfite solution
Distillation of the product
The pure distilled product