US4485049A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-stage crystallization of nitrilotriacetonitrile from a hot solution
Assignee: Solutia Inc
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Filing: 1983-01-03
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Granted: 1984-11-27
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Expires: 2003-01-03
Abstract
Abstract A process is disclosed for producing crystalline nitrilotriacetonitrile from a solution of nitrilotriacetonitrile and water in excess of 95° C., comprising: a. cooling the nitrilotriacetonitrile-water solution in a first stage to the range of about 70° C. to about 90° C., preferably from about 80° C. to about 90° C., and more preferably about 85° C., to produce a nitrilotriacetonitrile water slurry; and b. further cooling the nitrilotriacetonitrile-water slurry in a second stage to below about 35° C., carried out either continuously or in a batch process. Cooling in the first stage is preferably accomplished by recycling cooled nitrilotriacetonitrile-water slurry from the second stage. Cooling in the second stage is preferably accomplished by vacuum cooling.
Inventors
- 👤 Kent P. Lannert
- 👤 Chung Y. Shen
- 👤 Dat S. Trieu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:16
CPC Classifications
C; C07; C07C; C07C255/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
87 words
A two-stage process for producing crystalline nitrilotriacetonitrile from a solution of nitrilotriacetonitrile and water in excess of 95° C., comprising: a. feeding the nitrilotriacetonitrile-water solution to a first stage where it is being cooled to the range of about 70° C. to about 90° C. with a sojourn time at this first stage, at least about 10 minutes to produce a nitrilotriacetonitrile-water slurry; and b. further cooling the nitrilotriacetonitrile-water slurry in a second stage to below 35° C. wherein vacuum cooling is employed in said second stage.
Claim 2
Dependent Claim
87 words
A two-stage process for producing crystalline nitrilotriacetonitrile from a solution of nitrilotriacetonitrile and water in excess of 95° C., comprising: a. feeding the nitrilotriacetonitrile-water solution to a first stage where it is being cooled to the range of about 70° C. to about 90° C. with a sojourn time at this first stage, at least about 10 minutes to produce a nitrilotriacetonitrile-water slurry; and b. further cooling the nitrilotriacetonitrile-water slurry in a second stage to below 35° C. wherein vacuum cooling is employed in said second stage.
Claim 3
Dependent Claim
17 words
The process of claim 1 in which the process is carried on as a continuous crystallization process.
Claim 4
Dependent Claim
19 words
The process of claim 2 wherein the nitrilotriacetonitrile-water solution is the reaction mixture in which the nitrilotriacetonitrile is produced.
Claim 5
Dependent Claim
20 words
The process of claim 2 wherein the first stage temperature range is from about 80° C. to about 90° C.
Claim 6
Dependent Claim
14 words
The process of claim 2 wherein the first stage temperature is about 85° c.
Claim 7
Dependent Claim
16 words
The process of claim 2 wherein the first stage sojourn time is at least 10 minutes.
Claim 8
Dependent Claim
21 words
The process of Claim 2 wherein the first stage cooling is accomplished by recycling cooled nitrilotriacetonitrile-water mixture from the second stage.
Claim 9
Dependent Claim
16 words
The process of claim 2 wherein the second stage cooling is accomplished solely by vacuum cooling.
Claim 10
Dependent Claim
16 words
The process of claim 1 wherein the process is carried on as a batch crystallization process.
Claim 11
Dependent Claim
19 words
The process of claim 9 wherein the nitrilotriacetonitrile-water solution is the reaction mixture in which the nitrilotriacetonitrile is produced.
Claim 12
Dependent Claim
20 words
The process of claim 9 wherein the first stage temperature range is from about 80° C. to about 90° C.
Claim 13
Dependent Claim
14 words
The process of claim 9 wherein the first stage temperature is about 85° C.
Claim 14
Dependent Claim
16 words
The process of claim 9 wherein the first stage sojourn time is at least 10 minutes.
Claim 15
Dependent Claim
21 words
The process of claim 9 wherein the first stage cooling is accomplished by recycling cooled nitrilotriacetonitrile-water mixture from the second stage.
Claim 16
Dependent Claim
16 words
The process of claim 9 wherein the second stage cooling is accomplished solely by vacuum cooling.
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) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |