US3717675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for isolating acrylic acid from the reaction gases obtained by the oxidation of propylene or a acrolein
Assignee: Knapsack AG
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Filing: 1967-07-20
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Granted: 1973-02-20
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Expires: 1987-07-20
Abstract
Abstract Process for isolating acrylic acid from the reaction gases obtained by the oxidation of propylene or acrolein, wherein the hot reaction gases, which have a temperature of 300* to 600*C, are pre-cooled, wherein the resulting aqueous acrylic acid solution is heated to be freed from the acrolein contained therein, and wherein the resulting vapors, together with nonliquefied, acrolein-containing residual gas, are returned to the oxidation zone, the said process comprising the steps of precooling the reaction gas inside a heat exchanger down to a temperature of 100* to 200*C, subjecting thereafter the precooled gases to direct scrubbing with water having a temperature of 10* to 50*C and thereby cooling them further down to a temperature between 30* and 90*C, and heating the resulting aqueous, 10 to 45 percent acrylic acid solution to a temperature of about 100* to 120*C to expel residual acrolein therefrom.
Inventors
- 👤 K Sennewald
- 👤 A Hauser
- 👤 W Lork
- 👤 K Gehrmann
- 👤 K Steil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:09
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/25; C07C51/252; C07C51/42; C07C51/48
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
231 words
In the process for isolating acrylic acid from the reaction gases obtained by the oxidation of at least one member selected from the group consisting of propylene and acrolein, wherein the hot reaction gases, wHich have a temperature of 300* to 600*C and are formed essentially of acrolein, acrylic acid, oxygen, inert gases and steam, are cooled, wherein the resulting aqueous acrylic acid solution is heated to expel the acrolein contained therein, and wherein the resulting vapors, together with non-liquefied acrolein-containing residual gas, are returned to the oxidation zone, the improvement which comprises pre-cooling the hot reaction gases inside a heat exchanger down to a temperature of 100* to 200*C, subjecting thereafter the said pre-cooled gases in a tray or packed column to direct scrubbing with water having a temperature of 10* to 50*C and thereby cooling them further down to a temperature between 30* and 90*C so as to provide a residual gas for return to the oxidation zone which includes steam in an amount of at least 5 percent by volume of the gas subjected to oxidation, and heating the resulting aqueous, 10 to 45 percent acrylic acid solution to a temperature of about 100* to 120*C to expel residual acrolein therefrom and returning the resultant vapors together with the non-liquefied residual gas, which contains acrolein and the steam which is needed for the reaction, to the oxidation zone.
Claim 2
Dependent Claim
231 words
In the process for isolating acrylic acid from the reaction gases obtained by the oxidation of at least one member selected from the group consisting of propylene and acrolein, wherein the hot reaction gases, wHich have a temperature of 300* to 600*C and are formed essentially of acrolein, acrylic acid, oxygen, inert gases and steam, are cooled, wherein the resulting aqueous acrylic acid solution is heated to expel the acrolein contained therein, and wherein the resulting vapors, together with non-liquefied acrolein-containing residual gas, are returned to the oxidation zone, the improvement which comprises pre-cooling the hot reaction gases inside a heat exchanger down to a temperature of 100* to 200*C, subjecting thereafter the said pre-cooled gases in a tray or packed column to direct scrubbing with water having a temperature of 10* to 50*C and thereby cooling them further down to a temperature between 30* and 90*C so as to provide a residual gas for return to the oxidation zone which includes steam in an amount of at least 5 percent by volume of the gas subjected to oxidation, and heating the resulting aqueous, 10 to 45 percent acrylic acid solution to a temperature of about 100* to 120*C to expel residual acrolein therefrom and returning the resultant vapors together with the non-liquefied residual gas, which contains acrolein and the steam which is needed for the reaction, to the oxidation zone.
Claim 3
Dependent Claim
13 words
The process of claim 1, wherein the said reaction gases also contain propylene.
Claim 4
Dependent Claim
25 words
The process of claim 1, wherein the said reaction gases are pre-cooled inside the said heat exchanger down to a temperature of 110* to 150*C.
Claim 5
Dependent Claim
16 words
The process of claim 1, wherein the scrubbing water has a temperature of 20* to 40*C.
Claim 6
Dependent Claim
25 words
The process of claim 1, wherein the said pre-cooled reaction gases are scrubbed with 50 to 500 cc water per normal cubic meter reaction gas.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |