Abstract: A method for producing an unsaturated nitrile by subjecting propane to a vapor-phase catalytic ammoxidation reaction using a fluidized bed reactor in the presence of a composite oxide catalyst containing Mo, V, and Nb, the method comprising the step of: adding a tungsten compound into the fluidized bed reactor to adjust a molar ratio (W/Mo ratio) of tungsten contained in a tungsten compound to molybdenum contained in the composite oxide catalyst that exist within the fluidized bed reactor so that the molar ratio is in the range of 0.0001 to 0.1.

Abstract: An object of the present invention is to provide a method for, when stopping an ammoxidation reaction of propane, stopping the ammoxidation reaction safely and quickly, without causing a deterioration in catalytic activity or acrylonitrile yield. The method for stopping an ammoxidation reaction includes a supply stopping step of stopping a supply of propane, an oxygen-containing gas, and ammonia to a reactor where an ammoxidation reaction of propane is being carried out using a catalyst, and a reaction stopping step of supplying an inert gas to the reactor in an amount 10 to 300 times the catalyst volume per hour until the catalyst temperature reaches 380° C. or less, wherein after the supply stopping step, a time required until the catalyst temperature decreases to 360° C. or less is within 10 hours.

Abstract: An object of the present invention is to provide a method for, when stopping an ammoxidation reaction of propane, stopping the ammoxidation reaction safely and quickly, without causing a deterioration in catalytic activity or acrylonitrile yield. The method for stopping an ammoxidation reaction includes a supply stopping step of stopping a supply of propane, an oxygen-containing gas, and ammonia to a reactor where an ammoxidation reaction of propane is being carried out using a catalyst, and a reaction stopping step of supplying an inert gas to the reactor in an amount 10 to 300 times the catalyst volume per hour until the catalyst temperature reaches 380° C. or less, wherein after the supply stopping step, a time required until the catalyst temperature decreases to 360° C. or less is within 10 hours.

Abstract: A method for producing an unsaturated nitrile by a propane ammoxidation reaction, the method including: a step of measuring at least one physical property value selected from the group consisting of the normalized UV value and the reduction ratio of a catalyst contained in a reactor, and a step of maintaining or changing a reaction condition based on the measured physical property value.

Abstract: A method for producing an unsaturated nitrile by subjecting propane to a vapor-phase catalytic ammoxidation reaction using a fluidized bed reactor in the presence of a composite oxide catalyst containing Mo, V, and Nb, the method comprising the step of: adding a tungsten compound into the fluidized bed reactor to adjust a molar ratio (W/Mo ratio) of tungsten contained in a tungsten compound to molybdenum contained in the composite oxide catalyst that exist within the fluidized bed reactor so that the molar ratio is in the range of 0.0001 to 0.1.

Abstract: Disclosed is a catalyst for use in catalytic oxidation or ammoxidation of propane or isobutane in the gaseous phase, which comprises an oxide containing, in specific atomic ratios, molybdenum (Mo), vanadium (V), niobium (Nb) and antimony (Sb), wherein the oxide catalyst has a reduction ratio of from 8 to 12% and a specific surface area of from 5 to 30 m2/g. Also disclosed is a process for efficiently producing this catalyst.

Abstract: Disclosed is a catalyst for use in catalytic oxidation or ammoxidation of propane or isobutane in the gaseous phase, which comprises an oxide containing, in specific atomic ratios, molybdenum (Mo), vanadium (V), niobium (Nb) and antimony (Sb), wherein the oxide catalyst has a reduction ratio of from 8 to 12% and a specific surface area of from 5 to 30 m2/g. Also disclosed is a process for efficiently producing this catalyst.

Abstract: A safety valve device used for enclosed cells, in which safety valve device an elastic valve body, which has a cross section with not more than eight angles, is placed in a valve chamber formed between a cap type positive terminal and a dish type opening seal member. Owing to the above-described construction, the volume ratio of the elastic valve body to the interior of the valve chamber can be reduced to a low level. Moreover, the valve body is placed in the center of the interior of the valve chamber so as to seal a gas discharge port reliably, and minimize the variation of the safety valve operating pressure.