US3679728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing methylenebisiminodiacetonitrile
Assignee: WR Grace and Co
•
Filing: 1968-08-13
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Granted: 1972-07-25
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Expires: 1988-08-13
Abstract
Abstract This invention is directed to a process for preparing methylenebisiminodiacetonitrile comprising reacting, in an aqueous system having a pH of about 0.9-3.9, ammonia, from an ammonia source selected from the group consisting of hexamethylenetetramine and ammonia sulfate (the hexamethylenetetramine also being a formaldehyde source), formaldehyde, and HCN to form methylenebisiminodiacetonitrile; separating, drying, and recovering the methylenebisiminodiacetonitrile, all as recited hereinafter.
Inventors
- 👤 Charles R Morgan
- 👤 David A Daniels
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:05
CPC Classifications
C; C07; C07C; C07C255/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
20 words
The process of claim 1 in which the separated methylenebisiminodiacetonitrile is washed until it is substantially free of mineral acid.
Claim 2
Dependent Claim
57 words
The process of claim 2 in which the washed methylenebisiminodiacetonitrile is dried at about 10*-60* C. under a pressure of about 5-760 millimeter of mercury absolute pressure until the methylenebisiminodiacetonitrile is substantially free of moisture, the dry methylenebisiminodiacetonitrile having a purity of about 98-99 percent, a melting point of about 8486* C., and existing as white crystals.
Claim 3
Dependent Claim
20 words
The process of claim 3 in which the washed methylenebisiminodiacetonitrile is dried in the solid state at about 15*-40* C.
Claim 4
Dependent Claim
26 words
The process of claim 1 in which the methylenebisiminodiacetonitrile is obtained in a yiEld of at least about 70 percent of theory based on the ammonia.
Claim 5
Dependent Claim
14 words
The process of claim 1 in which the strong mineral acid is sulfuric acid.
Claim 6
Dependent Claim
12 words
The process of claim 1 in which the ammonia source is hexamethylenetetramine.
Claim 7
Dependent Claim
29 words
THe process of 1 in which the ammonia source is ammonium sulfate. -cm 9. The process of claim 1 in which the reaction mixture is reacted for 1-7 hours.
Claim 8
Dependent Claim
27 words
THe process of claim 1 in which the ammonia source, the formaldehyde and the HCN are present in a mole ratio of ammonia: formaldehyde:HCN of about 1:2.5-2.75:2-2.2.
Claim 9
Dependent Claim
21 words
The process of claim 1 in which the pH of the reaction mixture is maintained within the range of about 1.0-2.5.
References Cited (Backward Citations)
GB974787A
Cited
DE1159959B
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |