3,119,665 United States Patent Office Patented Jan. 28, 1964

1. 2 mixing the reactants is used. For example, on a labora 3,119,665 tory scale a mortar and pestle can be used to produce the PRODUCTION OF CALCUM SUPEROXDE desired abrasive mixing action. On a larger scale, a ball Joseph S. Hashman, Evans City, Jackie C. Renforth, mill reactor or similar type of grinding or mixing equip Valencia, and Jerry W. Berkstresser, Carlisle, Pa., ment can be used to provide the preferred abrasive mixing assignors to Callery Chemical Company, Pittsburgh, of the reactants. Pa., a corporation of Pennsylvania In one example of the method and practice of our in No Drawing. Fied May 31, 1960, Ser. No. 32,579 vention, potassium superoxide was mixed in a mortar and 8 Clains. (C. 23-187) pestle with an excess of calcium chloride based on the This invention relates to a new and improved method O equation above. After twenty minutes reaction time, the for producing calcium superoxide, Ca(O2)2. mixture was analyzed by X-ray and chemical analyses. The Superoxides in general are compounds rich in oxy The analyses showed that calcium superoxide, Ca(O2)2, gen and having high oxidizing power. Such compounds Was produced during the reaction, along with potassium are useful as oxygen sources in self-contained breathing chloride. No potassium superoxide remained unreacted apparatus and for other purposes in which their oxygen and only a small amount of calcium chloride was found. content provides advantageous utility. Calcium super The product was analyzed for superoxide oxygen using oxide has generally the properties attributable to the super the conventional method of reacting the compound with oxides as a class, and has found particular application in glacial acetic acid and diethylphthalate at 0 and measur the passivation of iron and steel, wherein it is used to pro ing the evolved oxygen. duce uniform coatings having improved rust-inhibiting 20 In these and other tests the general applicability of the characteristics. method was demonstrated and it was shown that the cal One method by which calcium superoxide has been pre cium superoxide thus produced is obtained in good yield pared involves the oxidation of calcium peroxide by re and in a desirable form. action with hydrogen peroxide, but this process has not According to the provisions of the patent statutes, we achieved any importance because it is very expensive and 25 have explained the principle and mode of practicing our difficult to carry out. Another method by which calcium invention and have described what we now consider to be superoxide has been made is by heating the peroxide with its best embodiments. However, we desire to have it un oxygen in the presence of a complex platinum-containing derstood that, within the scope of the appended claims, catalyst. This method, however, requires temperatures of the invention may be practiced otherwise than as specifi over 500 C. and high superatmospheric pressures. Thus, 30 cally described. it presents considerable difficulty in commercial operation We claim: and even on a small scale requires cumbersome and ex 1. A method for producing calcium superoxide, pensive equipment. It is an object of this invention to provide a novel, effi cient and economical method for the production of cal 35 which comprises reacting a calcium halide with a super cium superoxide, which provides improved operation over oxide selected from the group consisting of alkali metal those methods known heretofore. Superoxides and tetra (lower alkyl)ammonium superoxides Another object is to provide an easily carried out proc and recovering the calcium superoxide thus formed. ess by which calcium superoxide can be produced in 40 2. A method in accordance with claim 1 in which the simple, readily available equipment and with a minimum calcium halide and the superoxide are abrasively mixed. of capital investment. 3. A method in accordance with claim 1 in which the Other objects will become apparent from time to time calcium halide is calcium chloride and the superoxide is throughout the following specification and claims. potassium superoxide. The basis for this invention is our discovery that a 45 4. A method in accordance with claim 1 in which the calcium halide reacts with an alkali metal or tetra (lower calcium halide is calcium chloride and the superoxide is alkyl)ammonium superoxide to produce calcium super sodium superoxide. oxide, Ca(O2)2. No particular conditions of temperature 5. A method in accordance with claim 1 in which the or pressure are necessary to the operability of our method. calcium halide is calcium chloride and the superoxide is Using the reaction of calcium chloride with potassium 50 tetramethylammonium superoxide. Superoxide as an example, the reaction takes place in ac 6. A method in accordance with claim 1 in which the cordance with the following equation: calcium halide is calcium bromide and the superoxide is potassium superoxide. 7. A method in accordance with claim 1 in which the The Superoxides which are usable in the process de 55 calcium halide is calcium bromide and the superoxide is scribed above correspond to the empirical formula MO sodium superoxide. where M is an alkali metal, such as sodium or potassium, 8. A method in accordance with claim 1 in which the or a tetra (lower alkyl)ammonium radical, such as tetra calcium halide is calcium bromide and the superoxide is methylammonia, (CH3)4N, or tetraethylammonium, tetramethylammonium superoxide. (C2H5)4N+. Calcium halides in general may be used in the practice 60 References (Cited in the file of this patent of our invention. Particularly efficacious are calcium chloride and calcium bromide, which produce more effi UNITED STATES PATENTS cient reaction with generally fewer undesirable side re 2,648,596 Schechter ------Aug. 11, 1953 actions. OTHER REFERENCES Because the process involves the reaction of two solid 65 compounds, it is desirable to provide intimate mixing of Mellor: "A Comprehensive Treatise on Inorganic and the reactants in order to optimize the rate of the reaction Theoretical Chemistry,” Vol. 3, 1923, page 668, Longmans, and the yield obtained. Preferably a means of abrasively Green and Co., New York.