US3898249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making phthalic anhydride
Assignee: Wacker Chemie AG
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Filing: 1973-08-01
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Granted: 1975-08-05
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Expires: 1993-08-01
Abstract
Abstract A process for preparing phthalic anhydride by oxidation of naphthalene or o-xylene or a mixture thereof with air with the use of fixed bed catalysts consisting of a carrier coated with vanadium pentoxide and titanium dioxide, said process consisting of passing naphthalene or o-xylene, or a mixture of both, with air over a catalyst layer which contains 0.25 to 1.5% by weight of potassium ions calculated on the coating, said layer forming 40 to 70% by volume of the total catalyst mass, and thereafter passing the mixture over a catalyst layer the coating of which is potassium-free.
Inventors
- 👤 Klaus Felice
- 👤 Josef Sedlmeier
- 👤 Otto Wiedemann
- 👤 Walter Gierer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:04
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/255; C07C51/265; C07C51/31; C07C51/313; B; B01; B01J; B01J23/00; B01J23/16; B01J23/20; B01J23/22; B01J37/00; B01J37/02; B01J37/0215; B01J37/0219; B01J37/0221
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
141 words
IN A PROCESS FOR PREPARING PHATHALIC ANHYDRIDE BY THE OXIDATION OF NAPHTHALENE OR O-XYLENE OR A MIXTURE THEREOF WITH AIR EMPLOYING A FIXED BED CATALYST CONSISTING OF A CARRIER COATED WITH VANADIUM PENTOXIDE AND TITANIUM DIOXIDE, AT AN ELEVATED TEMPERATURE, THE IMPROVEMENT WHICH COMPRISES PASSING THE VAPORS OF NAPHTHALENE OR O-XYLENE OR A MIXTURE OF BOTH, WITH AIR, OVER A FIRST CATALYST LAYER CONSISTING OF A CARR IER COATED WITH VANADIUM PENTOXIDE AND TITANIUM DIOXIDE, SAID LAYER CONTAINING IN SAID COATING FROM ABOUT 3.25 TO ABOUT 1.5 PER CENT BY WEIGHT OF POTASSIUM IONS CALCULATED ON THE COATING, SAID LAYER FORMING 40 TO 70 PER CENT BY VOLUME OF THE TOTAL CATALYST MASS, AND THAN PASSING SAID VAPORS OVER A SECOND CATALYST LAYER CONSISTING OF A CARRIER COATED WITH VANADIUM PENTOXIDE AND TITANIUM DIOXIDE AND BEING SUBSTANTIALLY FREE FROM POTASSIUM IONS.
Claim 2
Dependent Claim
141 words
IN A PROCESS FOR PREPARING PHATHALIC ANHYDRIDE BY THE OXIDATION OF NAPHTHALENE OR O-XYLENE OR A MIXTURE THEREOF WITH AIR EMPLOYING A FIXED BED CATALYST CONSISTING OF A CARRIER COATED WITH VANADIUM PENTOXIDE AND TITANIUM DIOXIDE, AT AN ELEVATED TEMPERATURE, THE IMPROVEMENT WHICH COMPRISES PASSING THE VAPORS OF NAPHTHALENE OR O-XYLENE OR A MIXTURE OF BOTH, WITH AIR, OVER A FIRST CATALYST LAYER CONSISTING OF A CARR IER COATED WITH VANADIUM PENTOXIDE AND TITANIUM DIOXIDE, SAID LAYER CONTAINING IN SAID COATING FROM ABOUT 3.25 TO ABOUT 1.5 PER CENT BY WEIGHT OF POTASSIUM IONS CALCULATED ON THE COATING, SAID LAYER FORMING 40 TO 70 PER CENT BY VOLUME OF THE TOTAL CATALYST MASS, AND THAN PASSING SAID VAPORS OVER A SECOND CATALYST LAYER CONSISTING OF A CARRIER COATED WITH VANADIUM PENTOXIDE AND TITANIUM DIOXIDE AND BEING SUBSTANTIALLY FREE FROM POTASSIUM IONS.
Claim 3
Dependent Claim
18 words
The process according to claim 1 wherein the height of the catalyst layer totals 2.6 to 3.2 m.
Claim 4
Dependent Claim
31 words
The process according to claim 2 wherein the height of the potassium ion-containing layer is from 1.2 - 2.0 m and the height of the potassium ion-free layer is 1-1.8 m.
Claim 5
Dependent Claim
16 words
The process according to claim 1 wherein the atomic ratio of titanium : vanadium is 4.5:1.
References Cited (Backward Citations)
US2142678A
Cited
US3799886A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |