US4312815A
Expired / Lapsed
US
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Preparation of a zinc chelate having improved stability
Assignee: Dow Chemical Co
•
Filing: 1980-03-31
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Granted: 1982-01-26
•
Expires: 2000-03-31
Abstract
Abstract An improved process of preparing an aqueous solution of the zinc chelate of N-(2-hydroxyethyl) iminodiacetic acid wherein ammonia is added to the aqueous solution during its preparation to increase the solubility of zinc therein.
Inventors
- 👤 David A. Wilson
- 👤 Druce K. Crump
- 👤 Freddie Griffin, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:09
CPC Classifications
C; C07; C07F; C07F3/00; C07F3/003
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
68 words
In the process of making the zinc chelate of N-(2-hydroxyethyl)iminodiacetic acid wherein the mole ratio of chelant/zinc is substantially 1 and wherein a zinc salt, oxide or hydroxide is added to an aqueous solution of said chelant, the improvement which comprises adding to said aqueous solution sufficient ammonia, or ammonium hydroxide, to provide from about 1.75 to about 2.75 moles of NH 3 per mole of said chelant.
Claim 2
Dependent Claim
68 words
In the process of making the zinc chelate of N-(2-hydroxyethyl)iminodiacetic acid wherein the mole ratio of chelant/zinc is substantially 1 and wherein a zinc salt, oxide or hydroxide is added to an aqueous solution of said chelant, the improvement which comprises adding to said aqueous solution sufficient ammonia, or ammonium hydroxide, to provide from about 1.75 to about 2.75 moles of NH 3 per mole of said chelant.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein zinc and the N-(2-hydroxyethyl)iminodiacetic acid are present in the mole ratio of from about 0.98/1.0 to about 1.02/1.0, respectively.
Claim 4
Dependent Claim
23 words
The process of claim 1 wherein the final chelate solution is adjusted to a pH of within the range of 7.7 to 8.5.
Claim 5
Dependent Claim
12 words
The process of claim 3 wherein the pH is 7.9 to 8.2.
Claim 6
Dependent Claim
18 words
The process of claim 3 wherein the concentration of zinc in the solution is adjusted to about 5%.
Claim 7
Dependent Claim
34 words
An aqueous solution of zinc chelate containing about 5% zinc by weight which has been prepared by adding NH 3 to an aqueous solution containing a zinc salt, oxide or hydroxide and N-(2-hydroxyethyl)iminodiacetic acid.
Claim 8
Dependent Claim
34 words
An aqueous solution of zinc chelate containing about 5% zinc by weight which has been prepared by adding NH 3 to an aqueous solution containing a zinc salt, oxide or hydroxide and N-(2-hydroxyethyl)iminodiacetic acid.
Claim 9
Dependent Claim
17 words
The process of claim 1 wherein the chelant employed is a dialkali metal salt of N-(2-hydroxyethyl)iminodiacetic acid.
Claim 10
Dependent Claim
12 words
The process of claim 1 wherein the chelant is the free acid.
Claim 11
Dependent Claim
15 words
The process of claim 7 wherein the zinc salt is a water soluble zinc salt.
Claim 12
Dependent Claim
32 words
The process of claim 9 wherein the zinc salt is selected from ZnCl 2 , ZnSO 4 , Zn(C 2 H 3 O 2 ) 2 and Zn(NO 3 ) 2 .
Claim 13
Dependent Claim
16 words
The process of claim 8 wherein the zinc salt, oxide or hydroxide is relatively water insoluble.
Claim 14
Dependent Claim
22 words
The process of claim 11 wherein the zinc salt, oxide or hydroxide is selected from ZnO, Zn(OH) 2 and ZnCO 3 .
Claim 15
Dependent Claim
20 words
The process of claims 3 or 4 wherein the pH is adjusted by adding an acid to the chelate solution.
Claim 16
Dependent Claim
19 words
The process of claims 3 or 4 wherein the pH is adjusted by evaporating ammonia from the chelate solution.
Claim 17
Dependent Claim
21 words
The process of claim 7 wherein the order of addition of reactants is chelant, ammonia and zinc salt, oxide or hydroxide.
Claim 18
Dependent Claim
19 words
The process of claim 8 wherein the order of addition is chelant, zinc salt, oxide or hydroxide and ammonia.
Claim 19
Dependent Claim
10 words
A soluble zinc chelate of hydroxyethyliminodiacetic acid which contains ammonia.
Claim 20
Dependent Claim
10 words
A soluble zinc chelate of hydroxyethyliminodiacetic acid which contains ammonia.
Claim 21
Dependent Claim
18 words
The chelate of claim 17 wherein the molar ratio of chelant to zinc to ammonia is approximately 1:1:1.
References Cited (Backward Citations)
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US3131048A
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-25 | 1985-07-27 | 1986-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-25 | 1989-07-27 | 1990-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-25 | 1993-07-27 | 1994-01-26 | $7700.00 | Window Closed / Lapsed |