Abstract: Disclosed is a process for the preparation of maleic anhydride which comprises subjecting an aliphatic hydrocarbon having four or more carbon atoms to gas phase oxidation reaction in the presence of a catalyst, wherein supposing that the function of reaction product gas composition is FL and the function of temperature and pressure of reaction product gas is FR, the safety index F satisfies the following relationship (1): F=FL−FR>0  (1) According to the present invention, it is possible that the loss of unreacted hydrocarbon and maleic anhydride as reaction product due to non-catalytic oxidation reaction is prevented while effecting the reaction in a stable manner, whereby the yield of maleic anhydride can be kept maximum while assuring safety.

Abstract: The present invention relates to a method for the simultaneous production of acrylonitrile and acrylic acid by reacting propane with ammonia and oxygen in the gas phase catalytic oxidation in the presence of a metal oxide catalyst containing vanadium and at least one member selected from tellurium, antimony and molybdenum and adjusting the molar ratio of propane to ammonia to from 2 to 10 and the molar ratio of oxygen to ammonia to from 2 to 10.

Abstract: A process for producing maleic anhydride is described, which comprises (i) reacting a hydrocarbon with oxygen in a vapor phase in the presence of a catalyst to yield a reaction mixture gas containing maleic anhydride, (ii) bringing the reaction mixture gas into contact with an organic solvent to collect the maleic anhydride in the organic solvent, (iii) separating at least part of the maleic anhydride from the organic solvent, (iv) washing with an aqueous alkali solution at least part of the organic solvent from which maleic anhydride has been separated, and (v) reusing the resultant washed organic solvent and the residual organic solvent for contact with the reaction mixture gas.

Abstract: A method for producing a nitrile by a gas phase catalytic oxidation reaction of an alkane with ammonia in the presence of a catalyst, which comprises supplying the alkane and ammonia to an upper stream inlet of the catalyst layer, and separately supplying at least a part of the total amount of ammonia to a downstream position of the catalyst layer located downstream from the upper stream inlet of the catalyst layer.

Abstract: A catalystic composition suitable for producing acrylonitrile from propylene, ammonia and oxygen (or oxygen-containing gas), which composition is represented by the following formula:(Mo).sub.a (W).sub.b (Bi).sub.c (Pb).sub.d (B).sub.e (Sb).sub.f (X).sub.g (O).sub.h(where: X is chromium or iron; a, b, c, d, e, f, g and h denote respectively number of atoms for molybdenum, tungsten, bismuth, lead, boron, antimony, X and oxygen, and wherein, if it is given that a+b=12, 0.ltoreq.b.ltoreq.7, 0.4.ltoreq.c.ltoreq.7, 2.ltoreq.d.ltoreq.12, 0.2/22.ltoreq.e/a.ltoreq.40/22, 0.ltoreq.f/a.ltoreq.25/22, and 0.ltoreq.g/a.ltoreq.3/22; and h denotes the number of oxygen necessary for satisfying the atomic valence for the individual constituent elements other than oxygen).