Preparation of isopropyl nitrite
First, 93 mL of precooled 32% w/w HCl is mixed with 49 g isopropyl alcohol and the resulting mixture cooled in a salt–ice bath. (isopropyl alcohol is insoluble in concentrated sodium nitrite solution; hence, the reagents must be mixed in this order). Then, 45 g of sodium nitrite (0.65 mol, or an equal molar amount of potassium nitrite) is dissolved with magnetic stirring in 80 mL water in a 500-mL flat-bottom flask. This dissolution is substantially endothermic; thus, if done immediately prior to the reaction, no external cooling is required. The hydrochloric acid–isopropanol mixture is placed into a suitable dropping funnel with vented outlet and added to the vigorously stirred sodium nitrite solution in a steady stream over the course of 10–15 min, during which a small amount of nitrogen dioxide gas may form. Next, the same dropping funnel is used to separate the lower aqueous layer from the yellow oily isopropyl nitrite, which is then shaken with a similar volume of concentrated cooled sodium bicarbonate solution (shaking at room temperature results in a sudden pressure buildup). If there is no clean separation, a few mL of saturated sodium chloride solution may be added to the separating funnel. One obtains 50.4 g (0.57 mol) of isopropyl nitrite, which completely distills at 38°C–39°C, representing an 87% yield. Additional notes: Use ventilation as nitrogen dioxide is highly toxic and carcinogenic. Isopropyl nitrite is a potent vasodilator which may be absorbed through the skin. Inhalation or absorption of small amounts can cause severe headaches. Isopropyl nitrite is not shelf stable, thus it must be prepared prior to use (1-3 weeks). If desired, it can be dried over anhydrous magnesium sulfate for a few days. This compound may also be prepared by the “Victor-Meyer Reaction” using isopropyl iodide and silver nitrite.
Small-scale Synthesis of Laboratory Reagents with Reaction Modelling by Leonid Lerner, 119, CRC Press 2011; ISBN 9781439813126
Isopropyl nitrite, 541-42-4, ISOPROPYLNITRITE, propan-2-yl nitrite, NITROUS ACID, ISOPROPYL ESTER, 2-Propanol nitrite, Nitrous acid, 1-methylethyl ester, EINECS 208-779-0, Isopropylester kyseliny dusite [Czech], BRN 1698878, 2-propyl nitrite, iso-Propyl nitrite, 1-methylethyl nitrite, ISOPROPYL NATRITE, Isopropyl alcohol nitrite, AC1Q6RBD, UNII-2T3Y2PS0ZE, Nitrous acid isopropyl ester, 2T3Y2PS0ZE, Isopropylester kyseliny dusite, KSC269M1P, AC1L1W92, nitrous acid propan-2-yl ester, DTXSID3052191, CTK1G9617, SKRDXYBATCVEMS-UHFFFAOYSA-N, ACN-S002435, EBD43041, ZINC31483276, AKOS006272058, RL04006, CJ-17805, LS-96769, OR034535, SC-91207, DB-004045, FT-0658994, A829987, I14-6594
Isopropyl nitrile, MolPort-001-780-297, CID10929, 4-01-00-01474 (Beilstein Handbook Reference)