Patent US3932500A successfully refreshed from Google Patents.
US3932500A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovering anhydrous acrylic acid
Assignee: BASF SE
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Filing: 1972-07-17
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Granted: 1976-01-13
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Expires: 1992-07-17
Abstract
Abstract Acrylic acid practically devoid of water, acrolein, formaldehyde and acetic acid is obtained at particularly low cost by countercurrent scrubbing and quenching of the reaction gas formed in the catalytic oxidation of propylene and/or acrolein with a high-boiling, extremely hydrophobic solvent followed by processing of the extract.
Inventors
- 👤 Gerd Duembgen
- 👤 Heinz Engelbach
- 👤 Walter Frey
- 👤 Richard Krabetz
- 👤 Ulrich Lebert
- 👤 Hermann Spitzl
- 👤 Fritz Thiessen
- 👤 Carl-Heinz Willersinn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:57
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/25; C07C51/252; C07C51/42; C07C51/48
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
151 words
A continuous process for recovering anhydrous acrylic acid from a reaction gas which has been obtained by the catalytic oxidation of a compound selected from the group consisting of propylene, acrolein and mixtures thereof which process comprises: initially scrubbing said reaction gas which contains unreacted propylene and/or acrolein and impurities including water vapor, acetic acid, and formaldehyde countercurrently in an absorption column with a high boiling inert and extremely hydrophobic solvent selected from the group consisting of a hydrocarbon having a boiling point at standard pressure above 170°C and a viscosity within the temperature range of from 30° to 80°C of less than 10 centistokes, diphenyl ether, diphenyl and mixtures of the same to absorb acrylic acid from said reaction gas and to effect direct cooling of the reaction gas with said solvent; and thereafter recovering acrylic acid from said solvent by distillation and recycling said solvent to said absorption column.
Claim 2
Dependent Claim
151 words
A continuous process for recovering anhydrous acrylic acid from a reaction gas which has been obtained by the catalytic oxidation of a compound selected from the group consisting of propylene, acrolein and mixtures thereof which process comprises: initially scrubbing said reaction gas which contains unreacted propylene and/or acrolein and impurities including water vapor, acetic acid, and formaldehyde countercurrently in an absorption column with a high boiling inert and extremely hydrophobic solvent selected from the group consisting of a hydrocarbon having a boiling point at standard pressure above 170°C and a viscosity within the temperature range of from 30° to 80°C of less than 10 centistokes, diphenyl ether, diphenyl and mixtures of the same to absorb acrylic acid from said reaction gas and to effect direct cooling of the reaction gas with said solvent; and thereafter recovering acrylic acid from said solvent by distillation and recycling said solvent to said absorption column.
Claim 3
Dependent Claim
22 words
A process as claimed in claim 1 wherein said countercurrent scrubbing is carried out with a mixture of diphenyl and diphenyl ether.
Claim 4
Dependent Claim
25 words
A process as claimed in claim 2 wherein said mixture comprises about 25% by weight of diphenyl and 75% by weight of said diphenyl ether.
Claim 5
Dependent Claim
24 words
A process as claimed in claim 2 wherein said countercurrent scrubbing is carried out at a temperature of from about 30° to 80° C.
Claim 6
Dependent Claim
32 words
A process as claimed in claim 1 wherein maleic anhydride is removed from said solvent by distillation after acrylic acid is removed and before the solvent is recycled to said absorption column.
Claim 7
Dependent Claim
47 words
A process as claimed in claim 1 wherein said absorbed acrylic acid and solvent is passed to a desorber column wherein said absorbed acrylic acid and solvent are contacted countercurrently with a stripping gas to remove residual water and minor amounts of acrolein, acetic acid and formaldehyde.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |