A process for producing unsaturated nitrile, using a fluidized bed reactor having an internal space having a catalyst capable of being fluidized therein, a feed opening to feed a starting material gas comprising hydrocarbon to the internal space, and a discharge port to discharge a reaction product gas from the internal space, the process comprising a reaction step of subjecting the hydrocarbon to a vapor phase catalytic ammoxidation reaction in the presence of the catalyst in the internal space to produce the corresponding unsaturated nitrile, wherein when in the internal space, a space where an existing amount of the catalyst per unit volume is 150 kg/m.sup.3 or more is defined as a dense zone and a space where an existing amount of the catalyst per unit volume is less than 150 kg/m.sup.3 is defined as a sparse zone in the reaction step, a gas residence time in the sparse zone is 5 to 50 sec.

A process for producing unsaturated nitrile, using a fluidized bed reactor having an internal space having a catalyst capable of being fluidized therein, a feed opening to feed a starting material gas comprising hydrocarbon to the internal space, and a discharge port to discharge a reaction product gas from the internal space, the process comprising a reaction step of subjecting the hydrocarbon to a vapor phase catalytic ammoxidation reaction in the presence of the catalyst in the internal space to produce the corresponding unsaturated nitrile, wherein when in the internal space, a space where an existing amount of the catalyst per unit volume is 150 kg/m.sup.3 or more is defined as a dense zone and a space where an existing amount of the catalyst per unit volume is less than 150 kg/m.sup.3 is defined as a sparse zone in the reaction step, a gas residence time in the sparse zone is 5 to 50 sec.

A catalytic composition and process useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, hydrogen cyanide and acetonitrile and mixtures thereof, wherein the catalyst exhibiting increased selectivity to hydrogen cyanide compared to prior art catalysts.

A catalytic composition and process useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, hydrogen cyanide and acetonitrile and mixtures thereof, wherein the catalyst exhibiting increased selectivity to hydrogen cyanide compared to prior art catalysts.

Described are methods and composition for inhibiting polymerization of a monomer (e.g., styrene) composition using an aminated quinone antipolymerant, such as an aminated benzoquinone or aminated naphthoquinone antipolymerant having one or more secondary or tertiary amine group(s). The aminated quinone antipolymerant can be used with little or no nitroxyl group containing antipolymerant yet still provide excellent antipolymerant activity in a monomer-containing composition.

Described are methods and composition for inhibiting polymerization of a monomer (e.g., styrene) composition using an aminated quinone antipolymerant, such as an aminated benzoquinone or aminated naphthoquinone antipolymerant having one or more secondary or tertiary amine group(s). The aminated quinone antipolymerant can be used with little or no nitroxyl group containing antipolymerant yet still provide excellent antipolymerant activity in a monomer-containing composition.

A process for producing unsaturated nitrile, using a fluidized bed reactor and comprising a reaction step of subjecting hydrocarbon to a vapor phase catalytic ammoxidation reaction in the presence of a catalyst to produce the corresponding unsaturated nitrile, wherein when an internal space of the reactor is divided into two spaces of an upper space occupying a space from an upper end of an inlet of a cyclone to an upper end of the internal space and a lower space occupying a space below the upper end of the inlet of the cyclone and ranging to a dispersion plate, a ratio of an existing amount of the catalyst in the upper space to an existing amount of the catalyst in the lower space is 0.05 to 0.45 in the reaction step.

A process for producing unsaturated nitrile, using a fluidized bed reactor and comprising a reaction step of subjecting hydrocarbon to a vapor phase catalytic ammoxidation reaction in the presence of a catalyst to produce the corresponding unsaturated nitrile, wherein when an internal space of the reactor is divided into two spaces of an upper space occupying a space from an upper end of an inlet of a cyclone to an upper end of the internal space and a lower space occupying a space below the upper end of the inlet of the cyclone and ranging to a dispersion plate, a ratio of an existing amount of the catalyst in the upper space to an existing amount of the catalyst in the lower space is 0.05 to 0.45 in the reaction step.

A novel mixed oxide material is disclosed which contains molybdenum, vanadium, tellurium and niobium and the use of the molybdenum mixed oxide material as catalyst for the oxidative dehydrogenation of ethane to ethene or the oxidation of propane to acrylic acid and a process for producing the mixed oxide material.

A novel mixed oxide material is disclosed which contains molybdenum, vanadium, tellurium and niobium and the use of the molybdenum mixed oxide material as catalyst for the oxidative dehydrogenation of ethane to ethene or the oxidation of propane to acrylic acid and a process for producing the mixed oxide material.