US3941837A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating an aqueous solution of acrylamide
Assignee: Mitsui Toatsu Chemicals Inc
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Filing: 1974-05-28
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Granted: 1976-03-02
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Expires: 1994-05-28
Abstract
Abstract A method of purifying an aqueous solution of acrylamide, which has been formed by reacting acrylonitrile with water in the presences of the metallic copper catalyst, and which contains cuprous ions, comprising treating said aqueous solution in a reaction zone which is substantially free of an oxygen containing gas or liquid.
Inventors
- 👤 Shiro Asano
- 👤 Kiyotaka Yoshimura
- 👤 Masao Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:15
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/70; B01J23/72
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
75 words
In a method of purifying an aqueous solution of acrylamide containing from 1 to 1,000 ppm of cuprous ions wherein said aqueous solution is subjected to at least one of the steps of distillation, concentration, filtration, precipitation, treatment with active carbon, crystallization and ion-exchange treatment, the improvement wherein at least one of said steps is preformed in a manner that said aqueous solution does not come in contact with an oxygen containing gas or liquid.
Claim 2
Dependent Claim
75 words
In a method of purifying an aqueous solution of acrylamide containing from 1 to 1,000 ppm of cuprous ions wherein said aqueous solution is subjected to at least one of the steps of distillation, concentration, filtration, precipitation, treatment with active carbon, crystallization and ion-exchange treatment, the improvement wherein at least one of said steps is preformed in a manner that said aqueous solution does not come in contact with an oxygen containing gas or liquid.
Claim 3
Dependent Claim
25 words
A method according to claim 1 wherein said aqueous solution is formed by reacting acrylonitrile with water in the presence of a metallic copper catalyst.
Claim 4
Dependent Claim
26 words
A method according to claim 1 wherein said aqueous solution is prevented from contacting an oxygen-containing gas or liquid until all of said steps are completed.
Claim 5
Dependent Claim
58 words
A method according to claim 2, wherein said aqueous solution is prevented from contacting any oxygen-containing gas or liquid by filling at least a part of the space in the apparatus used for said at least one of said steps with a gas other than air or gaseous oxygen prior to introducing said aqueous solution into the apparatus.
Claim 6
Dependent Claim
19 words
A method according to claim 4, wherein said gas other than air or oxygen is gaseous nitrogen or steam.
Claim 7
Dependent Claim
48 words
A method according to claim 2, wherein said aqueous solution is prevented from contacting an oxygen-containing gas or liquid by filling the space in the apparatus used for said at least one of said steps with a deoxygenated liquid prior to introducing said aqueous solution into the apparatus.
Claim 8
Dependent Claim
24 words
A method according to claim 6, wherein said deoxygenated liquid is water, an aqueous solution of acrylamide, acrylonitrile or an aqueous solution of acrylonitrile.
Claim 9
Dependent Claim
48 words
A method according to claim 2, wherein said aqueous solution is prevented from contacting an oxygen-containing gas or liquid by mixing said aqueous solution of acrylamide with a deoxygenated liquid before said aqueous solution is introduced into the apparatus used for said at least one of said steps.
Claim 10
Dependent Claim
24 words
A method according to claim 8, wherein said deoxygenated liquid is water, an aqueous solution of acrylamide, acrylonitrile and an aqueous solution of acrylonitrile.
Claim 11
Dependent Claim
46 words
A method according to claim 2, wherein said aqueous solution is prevented from contacting an oxygen-containing gas or liquid by carrying out said at least one of said steps while feeding a gas other than air or gaseous oxygen into the apparatus used in that step.
Claim 12
Dependent Claim
20 words
A method according to claim 10, wherein said gas other than air or gaseous oxygen in gaseous nitrogen or steam.
Claim 13
Dependent Claim
30 words
A method according to claim 2, wherein the active carbon treatment of said aqueous solution is carried out while preventing said aqueous solution from contacting an oxygen-containing gas or liquid.
Claim 14
Dependent Claim
30 words
A method according to claim 2, wherein the ion exchange treatment of said aqueous solution is carried out while preventing said aqueous solution from contacting an oxygen-containing gas or liquid.
Claim 15
Dependent Claim
35 words
A method according to claim 2, wherein the active carbon treatment and the ion exchange treatment of said aqueous solution are carried out while preventing said aqueous solution from contacting an oxygen-containing gas or liquid.
Claim 16
Dependent Claim
34 words
A method according to claim 2, wherein the distillation, concentration and filtration or precipitation treatments of said aqueous solution are carried out while preventing said aqueous solution from contacting an oxygen-containing gas or liquid.
Claim 17
Dependent Claim
29 words
A method according to claim 2, wherein the crystallization treatment of said aqueous solution is carried out while preventing said aqueous solution from contacting an oxygen-containing gas or liquid.
Claim 18
Dependent Claim
44 words
A method according to claim 1, wherein the ion exchange treatment of said aqueous solution of crude acrylamide is carried out while preventing said aqueous solution from contact with an oxygen-containing gas or liquid in all the treatments until the ion exchange is finished.
Claim 19
Dependent Claim
55 words
A method according to claim 2, wherein an aqueous solution of crude acrylamide containing 5 to 500 ppm of cuprous ion is treated by way of distillation, filtration and ion exchange treatments as well as intermediate treatments for these treatments, while preventing said aqueous solution from contacting an oxygen-containing gas or liquid throughout these treatments.
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) | 1979-03-02 | 1979-09-01 | 1980-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-02 | 1983-09-01 | 1984-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-02 | 1987-09-01 | 1988-03-02 | $7700.00 | Window Closed / Lapsed |