Preparation of phthalic anhydride
US4046780A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1975 |
| Grant date | Sep 6, 1977 |
| Priority date | — |
| Expiry date | Oct 29, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/313
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
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 anata…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.