N.sub.2 O is a by-product of the nitric acid oxidation of alcohols and ketones, for example in the oxidation of cyclohexanone and cyclohexanol to adipic acid. N.sub.2 O is also used as an anesthetic especially in mior surgery such as tooth extraction.
N.sub.2 O has recently attacted attention as a possible atmospheric ozone depletion gas, and efforts are therefore under way to diminish the amount of N.sub.2 O that is released into the atmosphere.
U.S. Pat. No. 4,259,303 to Nakaji et al. discloses an apparatus for the treatment of N.sub.2 O anesthetic waste gas by contacting it with a catalyst comprising one or more of ferric oxide (Fe.sub.2 O.sub.3), cobalt oxide (CoO), cupric oxide (CuO), chromium oxide (Cr.sub.2 O.sub.3), manganese dioxide (MnO.sub.2), and nickel oxide (NiO).
U.S. Pat. No. 4,793,980 to Torobin discloses the conversion of nitrogen oxides (NOx) to nitrogen and oxygen using finely divided molecular sieve carbon particles. This patent also discloses hollow microsphere catalyst supports that may be made of zirconia, and indicates that hollow microsphere catalyst supports may be used to support various metal oxide catalysts. Among the various alternative metal oxides listed are nickel oxide or cobalt oxide.
USPTO Backgrounds
USPTO Backgrounds