Distillation of an alkyl nitrite.
Nitrites are not the best for health, especially volatile organic nitrites. Amyl nitrite and other alkyl nitrites are used in medicine for the treatment of heart diseases. They are potent vasodilators; they expand blood vessels, resulting in lowering of the blood pressure under seconds.
The distillate contains a lower deep blue layer and an upper yellowish thing. The yellow oil is the nitrite and the blue thing at the bottom is dinitrogen trioxide (N2O3). It was formed from the minor decomposition of the nitrite. N2O3 forms upon mixing equal parts of nitric oxide and nitrogen dioxide and cooling the mixture.