Abstract: A catalyst comprising a catalytically active material composed of 1 to 20 parts by weight as V.sub.2 O.sub.5 of vanadium oxide, 99 to 80 parts by weight of anatase-type titanium oxide being porous and having a particle diameter substantially of 0.4 to 0.7 micron and a specific surface area of 10 to 60 m.sup.2 /g, and per 100 parts by weight of the sum of said two components, 0.01 to 1 part by weight as Nb.sub.2 O.sub.5 of niobium oxide, 0.05 to 1.2 parts by weight as an oxide of at least one ingredient selected from the group consisting of potassium, cesium, rubidium and thallium, and 0.2 to 1.2 parts by weight as P.sub.2 O.sub.5 of phosphorus, and a porous carrier having an alumina content of not more than 10% by weight, a silicon carbide content of at least 80% by weight and an apparent porosity of at least 10% supporting said catalytically active material thereon, wherein the total volume of pores having a diameter of 0.15 to 0.

Abstract: A method for the disposal of waste gas, which method comprises (a) heating the incoming waste gas containing hydrocarbons, carbon monoxide, and other inflammable organic compounds with the gas obtained by removing heat from the outlet gas of the catalytic-oxidation reactor, (b) further heating the resultant hot waste gas with part of the outlet gas of the catalytic-oxidation reactor, (c) subjecting the heated waste gas to complete oxidation in the catalytic-oxidation reactor thereby rendering the waste gas no longer noxious, (d) diverting part of the outlet gas of the catalytic-oxidation reactor to be used for heating the aforementioned heated waste gas, (e) causing at least part of the outlet gas of the reactor which has been used for heating the waste gas to mingle with the remainder of the outlet gas of the reactor, (f) causing the remainder of the outlet gas of the reactor which has been used for heating the waste gas to mingle with the aforementioned heated waste gas, and (g) subjecting to heat recovery

Abstract: A process for producing phthalic anhydride, which comprises packing a catalyst into a multitube fixed bed converter, said catalyst comprising a catalytically active material composed of 1 to 20 parts by weight as V.sub.2 O.sub.5 of vanadium oxide, 99 to 80 parts by weight of anatase-type titanium oxide being porous and having a particle diameter substantially of 0.4 to 0.7 micron and a specific surface area of 10 to 60 m.sup.2 /g, and per 100 parts by weight of the sum of said two components, 0.01 to 1 part by weight as Nb.sub.2 O.sub.5 of niobium oxide, 0.05 to 1.2 parts by weight as an oxide of at least one ingredient selected from the group consisting of potassium, cesium, rubidium and thallium, and 0.2 to 1.2 parts by weight as P.sub.2 O.sub.