(EP946254-A1)      Method for reducing nitrogen oxides from an exhaust gas involves autothermically heating the exhaust gas using hydrocarbon(s) in the presence of ammonia and/or isocyanic acid under conditions effective for autocatalytic reduction of nitrogen oxides.    USE -   For reducing nitrogen oxides from an exhaust gas e.g from internal combustion engines.    ADVANTAGE -   Autocatalytic process provides self-sustained conversion of reactants and selective reduction of nitrogen oxides.    (US5985222-A)      Method for reducing nitrogen oxides from an exhaust gas involves autothermically heating the exhaust gas using hydrocarbon(s) in the presence of ammonia and/or isocyanic acid under conditions effective for autocatalytic reduction of nitrogen oxides.    USE -   For reducing nitrogen oxides from an exhaust gas e.g from internal combustion engines.    ADVANTAGE -   Autocatalytic process provides self-sustained conversion of reactants and selective reduction of nitrogen oxides.    (US6066303-A)      Method for reducing nitrogen oxides from an exhaust gas involves autothermically heating the exhaust gas using hydrocarbon(s) in the presence of ammonia and/or isocyanic acid under conditions effective for autocatalytic reduction of nitrogen oxides.    USE -   For reducing nitrogen oxides from an exhaust gas e.g from internal combustion engines.    ADVANTAGE -   Autocatalytic process provides self-sustained conversion of reactants and selective reduction of nitrogen oxides.    (JP2001503675-W)      Method for reducing nitrogen oxides from an exhaust gas involves autothermically heating the exhaust gas using hydrocarbon(s) in the presence of ammonia and/or isocyanic acid under conditions effective for autocatalytic reduction of nitrogen oxides.    USE -   For reducing nitrogen oxides from an exhaust gas e.g from internal combustion engines.    ADVANTAGE -   Autocatalytic process provides self-sustained conversion of reactants and selective reduction of nitrogen oxides.