Calcium superoxide is prepared in high yields by spreading a quantity of calcium peroxide piperoxyhydrate on the surface of a container over an area of 18 to 300 cm2/g of diperoxyhydrate; positioning said container in a vacuum chamber on a support structure through which a coolant fluid can be circulated; partially evacuating the chamber, allowing the temperature of the diperoxyhydrate to reach approximately 0 deg to approximately 40 deg c with the use of external heating or cooling fluid as needed, maintaining the temperature for a sufficient time to complete the disproportionation of the diperoxyhydrate to calcium superoxide, calcium hydroxide, oxygen, and water; while maintaining a partial vacuum, constantly and systematically removing the water as it is formed by sweeping the chamber with a current of dry inert gas and/or by condensing the water on a cold surface; and finally recovering the calcium superoxide produced. Calcium peroxide diperoxyhydrate is prepared by adding to cao2.8H2o sufficient concentrated h2o2 to effect the chemical transformation. Maintain the temperature at -15.5 Deg to -15.0 Deg c for 0.75 to 2 h. Filter, wash with dry isopropanol at -15 deg to -18.5 Deg c. Filter again and dry in a stream of co2-free air at relative humidity of 0- 0.5 pct. Store at -10 deg c, or preferably at -195 deg c (liquid n2). Note: it is not clear why this patent is listed as a Bureau patent, as the inventors are not Bureau of Mines personnel, and the patent appears to have been assigned to the National Aeronautics and Space Administration.
U.S. Pat. 4,101,644, July 18, 1978; Chem. Abstr. Not Found