Patent US3772156A successfully refreshed from Google Patents.
US3772156A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of acetic acid streams by distillation
Assignee: BP Chemicals Ltd
•
Filing: 1971-11-19
•
Granted: 1973-11-13
•
Expires: 1991-11-19
Abstract
Abstract The purification of acetic acid to remove very minor amounts of iodine in the parts per billion range is effected by means of a two-column distillation of the acid containing such iodine contamination in the presence of a chemical agent which is either an alkali metal compound, an alkaline earth metal compound, or a mixture of either of these compounds with hypophosphorous acid.
Inventors
- 👤 W Johnson
- 👤 T Singleton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:22
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/43; C07C51/44; C07C51/487
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
54 words
The process of claim 1 wherein said stream of acetic acid is introduced into the middle third of said first distillation column, said stream of chemical agent is introduced into said acetic acid stream, and said overhead stream from said first distillation column is introduced into the upper half of said second distillation column.
Claim 2
Dependent Claim
58 words
The process of claim 1 wherein said stream of acetic acid is introduced into the middle third of said first distillation column, said stream of chemical agent is introduced into the upper half of said first distillation column, and said overhead stream from said first distillation column is introduced into the upper half of said second distillation column.
Claim 3
Dependent Claim
20 words
The process of claim 2 wherein said chemical agent is a mixture of said alkali metal compounds and hypophosphorous acid.
Claim 4
Dependent Claim
18 words
The process of claim 4 wherein said chemical agent is a mixture of potassium acetate and hypophosphorous acid.
Claim 5
Dependent Claim
18 words
The process of claim 4 wherein said chemical agent is a mixture of potassium hydroxide and hypophosphorous acid.
Claim 6
Dependent Claim
64 words
The process of claim 4 wherein the amount of said alkali metal compound employed is in stoichiometric excess of the amount of ionic iodine in the acetic acid stream being introduced into said first distillation column and the amount of hypophosphorous acid is in stoichiometric excess of the amount of free iodine in the acetic acid stream being introduced into said first distillation column.
Claim 7
Dependent Claim
62 words
The process of claim 5 wherein the amount of potassium acetate employed is in stoichiometric excess of the amount of ionic iodine in the acetic acid being introduced into said first distillation column and the amount of the hypophosphorous acid is in stoichiometric excess of the amount of free iodine in the acetic acid stream being introduced into said first distillation column.
Claim 8
Dependent Claim
61 words
The process of claim 6 wherein the amount of potassium hydroxide employed is in stoichiometric excess of the amount of ionic iodine in the acetic acid stream being introduced into said first distillation column and the amount of hypophosphorous acid is in stoichiometric excess of the amount of free iodine in the acetic acid being introduced into said first distillation column.
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) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |