US3923841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making tetra sodium and tetra potassium 2,2,5,5-tetrahydrofurantetracarboxylate
Assignee: Monsanto Co
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Filing: 1974-11-06
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Granted: 1975-12-02
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Expires: 1994-11-06
Abstract
Abstract Colorless, crystalline tetrasodium or tetrapotassium tetrahydrofuran-2,2,5,5-tetracarboxylate and hydrates thereof useful as sequestrants and detergency builders are prepared by addition of 2,2,5,5-tetracyanotetrahydrofuran to aqueous sodium or potassium hydroxide.
Inventors
- 👤 Marvin M Crutchfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 00:43
CPC Classifications
C; C11; C11D; C11D3/00; C11D3/16; C11D3/20; C11D3/2096; C07; C07D; C07D307/00; C07D307/02; C07D307/04; C07D307/18; C07D307/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
9 words
A PROCESS FOR PREPARING COMPOUNDS REPRESENTED BY THE FORMULA
Claim 2
Dependent Claim
9 words
A PROCESS FOR PREPARING COMPOUNDS REPRESENTED BY THE FORMULA
Claim 3
Dependent Claim
15 words
The process of claim 1 further comprising crystallizing hydrates of said compounds from the solution.
Claim 4
Dependent Claim
18 words
The process of claim 2 wherein M is sodium and the hydrolysis is conducted in excess sodium hydroxide.
Claim 5
Dependent Claim
35 words
The process of claim 2 wherein said hydrates are crystallized by providing from 10 to 30% by weight sodium hydroxide in said solution in addition to the sodium hydroxide required for hydrolysis of the 2,2,5,5-tetracyanotetrahydrofuran.
Claim 6
Dependent Claim
15 words
The process of claim 2 further comprising heating the hydrates to liberate water of hydration.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |