The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 1977
Filed:
Oct. 29, 1975
Nippon Shokubai Kagaku Kogyo Co., Ltd., Osaka, JA;
Abstract
A method for preparing phthalic anhydride by the catalytic vapor phase oxidation of either ortho-xylene or naphthalene, which comprises passing a gas comprising a molecular oxygen, an inert gas and a member of the group consisting of ortho-xylene and naphthalene first through a catalyst A comprising a catalytically active substance on a porous inert carrier, said catalytically active substance consisting essentially of 1 to 20 parts by weight of V.sub.2 O.sub.5, 99 to 80 parts by weight of anatase-type TiO.sub.2, and, based on the total weight of V.sub.2 O.sub.5 and TiO.sub.2, 0.01 to 1.0% by weight of Nb.sub.2 O.sub.5, 0.5 to 1.1% by weight of P.sub.2 O.sub.5, 0 to 0.25% by weight of K.sub.2 O and 0 to 0.5% by weight of Cs.sub.2 O, the total weight of the K.sub.2 O and Cs.sub.2 O being at least 0.05% by weight, 0.05 to 0.3% by weight of Na.sub.2 O and 0 to 0.5% by weight of Rb.sub.2 O, said porous inert carrier comprising essentially SiC, and thereafter through a catalyst B comprising a catalytically active substance on a porous inert carrier, said catalytically active substance consisting essentially of 1 to 20 parts by weight of V.sub.2 O.sub.5, 99 to 80 parts by weight of anatase-type TiO.sub.2, and, based on the total weight of the V.sub.2 O.sub.5 and TiO.sub.2, 0.01 to 1.0% by weight of Nb.sub.2 O.sub.5, 1.2 to 2.5% by weight of P.sub.2 O.sub.5, 0 to 0.25% by weight of K.sub.2 O and 0 to 0.5% by weight of Cs.sub.2 O, the total weight of the K.sub.2 O and Cs.sub.2 O being at least 0.05% by weight, 0.05 to 0.3% by weight of Na.sub.2 O and 0 to 0.5% by weight of Rb.sub.2 O, said porous inert carrier comprising essentially SiC.