Potassium Amide

[17242-52-3] H2KN (MW 55.13) InChI = 1S/K.H2N/h;1H2/q+1;-1 InChIKey = FEMRXDWBWXQOGV-UHFFFAOYSA-N (strong base and nucleophile; used for the generation and trapping of arynes; has been used extensively to study the reactivity of heterocyclic systems) Solubility: 1.7 M in liquid ammonia;1 1.3 × 10−4 M in THF.2 Preparative Methods: a solution of potassium amide in liquid ammonia is prepared by adding pieces of Potassium to liquid Ammonia in an ordinary three-necked flask equipped with a mechanical stirrer.3 A piece of potassium is added to liquid ammonia and after the appearance of a blue color, a few crystals of iron(III) nitrate hydrate are added as catalyst. The remaining pieces of potassium are added at a rate which maintains active hydrogen evolution. Discharge of the deep blue color indicates complete conversion to potassium amide. External cooling is not required since the evaporation of ammonia will provide ample cooling.4 If the reaction must be maintained at −78 °C then a dry ice–acetone condenser is necessary, otherwise an air condenser is sufficient. The resulting opaque mixture contains potassium amide which is mostly in solution. A more elaborate two-flask assembly for the generation and transfer of a potassium amide solution has also been described.5 Handling, Storage, and Precautions: potassium amide is flammable and ignites on contact with moisture. Excess material is destroyed by careful treatment with ethanol or isopropanol. In the preparation of potassium amide the following precautions should be noted. Potassium is a silvery gray metal but it can form an explosive peroxide coating. If it acquires an orange or red color or an appreciable oxide coating it should be considered extremely hazardous. Extreme caution should be exercised in any attempt to isolate potassium amide as it is suspected to be shock sensitive following partial oxidation. An explosion has been reported during the isolation of dry potassium amide.6 Reactions should be performed in a fume hood to prevent exposure to ammonia. Hydrogen is evolved during the generation of potassium amide. No ignition source should be present.