Patent US2025635A successfully refreshed from Google Patents.
Patent US3988360A successfully refreshed from Google Patents.
US3988360A
Expired / Lapsed
US
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Process for preparing iminodiacetonitrile
Assignee: WR Grace and Co
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Filing: 1975-09-08
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Granted: 1976-10-26
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Expires: 1995-09-08
Abstract
Abstract Iminodiacetonitrile is prepared by a process comprising: (a) forming an aqueous reaction mixture by admixing water, hexamethylenetetramine, formaldehyde, and HCN; and (b) forming iminodiacetonitrile by passing the aqueous reaction mixture through a continuous reaction zone while maintaining the temperature within the continuous reaction zone at 50 DEG -250 DEG C. The resulting iminodiacetonitrile can be recovered or it can be hydrolyzed to form an alkali metal salt of iminodiacetic acid which can be recovered or converted to iminodiacetic acid which can be recovered.
Inventors
- 👤 Roger Robert Gaudette
- 👤 James Edward Philbrook
- 👤 Jon Carl Thunberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:00
CPC Classifications
C; C07; C07C; C07C255/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
81 words
A continuous process for preparing iminodiacetonitrile comprising: a. continuously preparing an aqueous reaction mixture of hexamethylenetetramine, formaldehyde, and HCN having a mole ratio of hexamethylenetetramine to formaldehyde to HCN of 1:1-2.2:6.9-8.6 in a continuous reaction zone by continuously feeding an aqueous hexamethylenetetramine solution having a temperature of 0°-80° C, an aqueous formaldehyde solution having a temperature of 0-80° C, and HCN having a temperature of 0°-25° C, into the continuous reaction zone, the pH of the aqueous reaction mixture being 5-10;
Claim 2
Dependent Claim
81 words
A continuous process for preparing iminodiacetonitrile comprising: a. continuously preparing an aqueous reaction mixture of hexamethylenetetramine, formaldehyde, and HCN having a mole ratio of hexamethylenetetramine to formaldehyde to HCN of 1:1-2.2:6.9-8.6 in a continuous reaction zone by continuously feeding an aqueous hexamethylenetetramine solution having a temperature of 0°-80° C, an aqueous formaldehyde solution having a temperature of 0-80° C, and HCN having a temperature of 0°-25° C, into the continuous reaction zone, the pH of the aqueous reaction mixture being 5-10;
Claim 3
Dependent Claim
44 words
b. continuously preparing an aqueous system containing the iminodiacetonitrile by continuously passing the aqueous reaction mixture through the continuous reaction zone while maintaining the temperature within the continuous reaction zone at 50°-250° C, residence time in the continuous reaction zone being 0.05-20 minutes; and
Claim 4
Dependent Claim
44 words
b. continuously preparing an aqueous system containing the iminodiacetonitrile by continuously passing the aqueous reaction mixture through the continuous reaction zone while maintaining the temperature within the continuous reaction zone at 50°-250° C, residence time in the continuous reaction zone being 0.05-20 minutes; and
Claim 5
Dependent Claim
10 words
c. continuously recovering the iminodiacetonitrile exit the continuous reaction zone.
Claim 6
Dependent Claim
10 words
c. continuously recovering the iminodiacetonitrile exit the continuous reaction zone.
Claim 7
Dependent Claim
17 words
The process of claim 1 in which, the temperature within the continuous reaction zone is 120°-170° C.
Claim 8
Dependent Claim
18 words
The process of claim 1 in which the residence time in the continuous reaction zone is 0.1-5 minutes.
Claim 9
Dependent Claim
16 words
The process of claim 1 in which the pH of the aqueous reaction mixture is 6.5-9.5.
Claim 10
Dependent Claim
27 words
The process of claim 1 in which the aqueous system exit the continuous reaction zone is cooled to 0°-40° C to cause the iminodiacetonitrile to separate therefrom.
Claim 11
Dependent Claim
18 words
The process of claim 1 in which the mole ratio of hexamethylenetetramine to formaldehyde to HCN is 1:1.6-2.2:7.2-8.0
Claim 12
Dependent Claim
18 words
The process of claim 1 in which the mole ratio of hexamethylenetetramine to formaldehyde to HCN is 1:1.8:7.6.
Claim 13
Dependent Claim
25 words
The process of claim 1 in which the aqueous hexamethylenetetramine solution and the formaldehyde solution are admixed before being fed into the continuous reaction zone.
Claim 14
Dependent Claim
45 words
The process of claim 1 in which the formaldehyde solution, the HCN, and an acid stabilizer are admixed and fed into the continuous reaction zone, the acid stabilizer being present in an amount effective for forming an acid stabilizer aqueous admixture of formaldehyde and HCN.
References Cited (Backward Citations)
US3904668A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |