US3721610A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the separation of lactic acid from water and nitric acid by rapid preevaporation and distillation
Assignee: Rhone Poulenc SA
•
Filing: 1970-11-23
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Granted: 1973-03-20
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Expires: 1990-11-23
Abstract
Abstract Lactic acid is recovered from aqueous mixtures containing it together with nitric acid, e.g. obtained by hydrolysis of the oxidation product of propylene with nitric acid, by passing the mixture into a rapid evaporator operating at a pressure less than 200 mm. mercury with a residence time less than 5 minutes to give a vaporized phase containing at least 60 percent by weight of the water and nitric acid and less than 40 percent by weight of the lactic acid, passing this vaporized phase together with nonvaporized material directly to a distillation column operating under reduced pressure and recovering the lactic acid as bottom product.
Inventors
- 👤 G Chaintron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:41
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/27; C07C51/275; C07C51/42; C07C51/43; C07C51/44
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
21 words
A process according to claim 1 wherein the residence time of the mixture in the evaporator is less than 1 minute.
Claim 2
Dependent Claim
18 words
A process according to claim 1 wherein the pressure in the evaporator is less than 100 mm. mercury.
Claim 3
Dependent Claim
40 words
A process according to claim 1 wherein the vaporized product contains at least 80 percent by weight of the nitric acid and water in the mixture and less than 20 percent by weight of the lactic acid in the mixture.
Claim 4
Dependent Claim
26 words
A process according to claim 1 wherein the mixture is obtained by hydrolysis of the product obtained by oxidizing propylene with nitric acid and/or nitrogen peroxide.
Claim 5
Dependent Claim
39 words
A process according to claim 1 wherein the evaporator is connected to the middle zone of the column and is located along an inclined or vertical axis so that the fluids flowing through it circulate in an ascending manner.
Claim 6
Dependent Claim
87 words
A process according to claim 1 wherein the mixture is a mixture of nitric acid, lactic acid and water in a weight ratio of about 40:15:45, and is fed into a rapid evaporator operating at about 100*C. at a pressure of about 40 mm. mercury with a residence time in the evaporator of about 0.02 seconds to give a vaporized fraction containing about 90 percent by weight of the water aNd nitric acid and 5 percent by weight of the lactic acid present in the original mixture.
Claim 7
Dependent Claim
127 words
A process according to claim 1 wherein the mixture is a mixture of nitric acid, lactic acid and water in a weight ratio of about 40:15:45 and is fed into a rapid evaporator operating at about 100*C. at a pressure of about 40 mm mercury to give a vaporized fraction containing about 80 percent by weight of the nitric acid and water and about 2 percent by weight of the lactic acid present in the original mixture which is passed to the distillation column and a non-vaporized fraction which is passed to a second rapid evaporator operating at about 130*C. at a pressure of about 40 mm mercury to give a second vaporized fraction and a non-vaporized fraction, both of which are fed to the distillation column.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |