Patent US3984466A successfully refreshed from Google Patents.
US3984466A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrolysis of 3,5-diamino benzoic acid to produce alpha-resorcylic acid
Assignee: Beazer East Inc
•
Filing: 1975-01-17
•
Granted: 1976-10-05
•
Expires: 1995-01-17
Abstract
Abstract Alpha-resorcylic acid is produced by the hydrolysis of 3,5-diamino benzoic acid in an aqueous solution of ammonium bisulfate. The reactants are contacted at an elevated temperature for a period of time sufficient to hydrolyze the 3,5-diamino benzoic acid to alpha-resorcylic acid and the alpha-resorcylic acid so produced is separated from the reaction mixture. The ammonium sulfate is regenerated to ammonium bisulfate by removing the water and thermally decomposing the by-product ammonium sulfate at an elevated temperature.
Inventors
- 👤 Nicholas P. Greco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:50
CPC Classifications
C; C01; C01C; C01C1/00; C01C1/24; C07; C07C; C07C51/00; C07C51/347; C07C51/367
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
94 words
A method of making alpha-resorcylic acid comprising: a. contacting 3,5-diamino benzoic acid with ammonium bisulfate in an aqueous solution that contains 4 to 12 moles of ammonium bisulfate per mole of 3,5-diamino benzoic acid and 40 to 120 moles of water per mole of 3,5-diamino benzoic acid and that is at a temperature of 200° to 300°C. for a period of 1/2 to 13 hours to hydrolyze said 3,5-diamino benzoic acid to alpha-resorcylic acid, b. cooling said hydrolysis reaction mixture, and c. extracting said alpha-resorcylic acid from said solution with a water-immiscible organic solvent.
Claim 2
Independent Claim
94 words
A method of making alpha-resorcylic acid comprising: a. contacting 3,5-diamino benzoic acid with ammonium bisulfate in an aqueous solution that contains 4 to 12 moles of ammonium bisulfate per mole of 3,5-diamino benzoic acid and 40 to 120 moles of water per mole of 3,5-diamino benzoic acid and that is at a temperature of 200° to 300°C. for a period of 1/2 to 13 hours to hydrolyze said 3,5-diamino benzoic acid to alpha-resorcylic acid, b. cooling said hydrolysis reaction mixture, and c. extracting said alpha-resorcylic acid from said solution with a water-immiscible organic solvent.
Claim 3
Dependent Claim
41 words
The method of claim 1 wherein the solution from which the alpha-resorcylic acid has been extracted is again maintained at a temperature of 200° to 300°C. for an additional period of time to hydrolyze residual 3,5-diamino benzoic acid to alpha-resorcylic acid.
Claim 4
Independent Claim
150 words
A method of making alpha-resorcylic acid comprising: a. contacting 3,5-diamino benzoic acid with ammonium bisulfate in an aqueous solution that contains 4 to 12 moles of ammonium bisulfate per mole of said 3,5-diamino benzoic acid and 40 to 120 moles of water per mole of said 3,5-diamino benzoic acid and that is at a temperature of 200° to 300°C. for a period of 1/2 to 13 hours to hydrolyze said 3,5-diamino benzoic acid to alpha-resorcylic acid, b. cooling said hydrolysis reaction mixture, c. extracting said alpha-resorcylic acid from said solution with an inert water-immiscible organic solvent, thereafter d. evaporating the water from said solution to obtain a residue consisting essentially of ammonium sulfate and ammonium bisulfate, and e. heating said residue to an elevated temperature of 210° to 450°C. to convert said ammonium sulfate to ammonium bisulfate for reuse to hydrolyze more of said 3,5-diamino benzoic acid to alpha-resorcylic acid.
Claim 5
Independent Claim
150 words
A method of making alpha-resorcylic acid comprising: a. contacting 3,5-diamino benzoic acid with ammonium bisulfate in an aqueous solution that contains 4 to 12 moles of ammonium bisulfate per mole of said 3,5-diamino benzoic acid and 40 to 120 moles of water per mole of said 3,5-diamino benzoic acid and that is at a temperature of 200° to 300°C. for a period of 1/2 to 13 hours to hydrolyze said 3,5-diamino benzoic acid to alpha-resorcylic acid, b. cooling said hydrolysis reaction mixture, c. extracting said alpha-resorcylic acid from said solution with an inert water-immiscible organic solvent, thereafter d. evaporating the water from said solution to obtain a residue consisting essentially of ammonium sulfate and ammonium bisulfate, and e. heating said residue to an elevated temperature of 210° to 450°C. to convert said ammonium sulfate to ammonium bisulfate for reuse to hydrolyze more of said 3,5-diamino benzoic acid to alpha-resorcylic acid.
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) | 1979-10-05 | 1980-04-05 | 1980-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-05 | 1984-04-05 | 1984-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-05 | 1988-04-05 | 1988-10-05 | $7700.00 | Window Closed / Lapsed |