US3917693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for concentrating an acrylamide aqueous solution
Assignee: Mitsui Toatsu Chemicals Inc
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Filing: 1972-12-04
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Granted: 1975-11-04
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Expires: 1992-12-04
Abstract
Abstract A method for economically concentrating an acrylamide aqueous solution by catalytic hydration without substantial deterioration in the product. According to the method, an acrylamide aqueous solution obtained from catalytic hydration, is concentrated by distillation while maintaining the solution in good contact with at least 0.1 mole. or more of air per mole. of water distilled from the acrylamide aqueous solution.
Inventors
- 👤 Shiro Asano
- 👤 Kiyotaka Yoshimura
- 👤 Ryoji Tsuchiya
- 👤 Tadatoshi Honda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:57
CPC Classifications
C; C07; C07C; C07C233/00; C07C233/01; C07C233/02; C07C233/09
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
57 words
METHOD FOR CONCENTRATING ACRYLAMIDE AQUEOUS SOLUTIONS COMPRISING CONCENTRATING THE ACRYLAMIDE AQUEOUS SOLUTION BY EVAPORATING THE WATER CONTENT THEREOF WHILE MAINTAINING THE SAID SOLUTION IN CONTACT WITH FROM 0.1 TO 30 MOLES OF AIR PER MOLE OF WATER BEING EVAPORATED AT A TEMPERATURE OF BETWEEN 60*C AND 100*C AND A PRESURE OF BETWEEN 3,678 AND 200 MM. HG.
Claim 2
Dependent Claim
57 words
METHOD FOR CONCENTRATING ACRYLAMIDE AQUEOUS SOLUTIONS COMPRISING CONCENTRATING THE ACRYLAMIDE AQUEOUS SOLUTION BY EVAPORATING THE WATER CONTENT THEREOF WHILE MAINTAINING THE SAID SOLUTION IN CONTACT WITH FROM 0.1 TO 30 MOLES OF AIR PER MOLE OF WATER BEING EVAPORATED AT A TEMPERATURE OF BETWEEN 60*C AND 100*C AND A PRESURE OF BETWEEN 3,678 AND 200 MM. HG.
Claim 3
Dependent Claim
31 words
Method according to claim 1, wherein the acrylamide aqueous solution is concentrated while maintaining the solution in contact with 0.5 to 15 moles. of air per mole. of water being evaporated.
Claim 4
Dependent Claim
30 words
Method according to claim 1, wherein the acrylamide aqueous solution is the product of a catalytic hydration and the solution is concentrated after removal of unreacted acrylonitrile residue contained therein.
Claim 5
Dependent Claim
38 words
Method according to claim 3, wherein said catalytic hydration employs a catalyst selected from the group consisting of Raney copper, reduced copper, reduced-copper chromium, copper powder-cupric chloride, silver oxide-chromium oxide and zinc salts of acid cation exchange resins.
Claim 6
Dependent Claim
61 words
Method for concentrating an acrylamide aqueous solution according to claim 2, wherein said acrylamide aqueous solution is the product of a Raney copper-catalyzed hydration and wherein said solution is concentrated under a pressure in the range of 3, 678 to 200 mmHg while maintaining said solution in contact with 0.5 to 15 moles. of air per mole. of water being evaporated.
Claim 7
Dependent Claim
17 words
The method according to claim 1, wherein the acrylamide aqueous solution is heated while bubbling air thereinto.
Claim 8
Dependent Claim
28 words
The method according to claim 1, wherein the acrylamide aqueous solution is sprayed into a flow of hot air to separate a concentrated solution for obtaining acrylamide crystals.
Claim 9
Dependent Claim
22 words
The method according to claim 1, wherein the acrylamide aqueous solution is concentrated into a thin liquid film within an air flow.
Claim 10
Dependent Claim
23 words
The method according to claim 1, wherein the acrylamide aqueous solution is first preheated, then mixed with air and, finally, concentrated by evaporation.
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) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |