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US3644444A Expired / Lapsed US ⏱️ 0.0 years remaining

Production of metal chelates

Assignee: WR Grace and Co
•
Filing: 1970-10-15
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Granted: 1972-02-22
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Expires: 1990-10-15
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Abstract

Abstract AN ALKALI METAL SALT OF A POLYVALENT METAL CHELATE OF A CHELATING AMINOACETIC ACID IS FORMED BY: (1) BOILING A MIXTURE OF; (A) WATER; (B) AN AMINE PRECURSOR OF THE SAID ACID; (C) FORMALDEHYDE; (D) A CYANIDE OF THE POLYVALENT METAL; (E) AN ALKALI METAL HYDROXIDE; AND (F) AN ALKALI METAL CYANIDE, AND ADDING THERETO THE CHELATING AMINOACETIC ACID IN ITS FREE FORM TO REACT WITH UNREACTED POLYVALENT METAL CYANIDE. (2) BOILING A MIXTURE OF; (A) WATER; (B) AN AMINE PRECURSOR OF THE SAID ACID; (C) FORMALDEHYDE; (D) A POLYVALENT METAL HYDROXIDE OR OXIDE; (E) AN ALKALI METAL HYDROXIDE; AND (F) HYDROGEN CYANIDE AND ADDING THERETO THE CHELATING AMINOACETIC ACID IN ITS FREE FORM TO REACT WITH UNREACTED POLYVALENT METAL HYDROXIDE OR OXIDE.

Inventors

  • 👤 Felix B Popper
  • 👤 Albert H Levesque

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 06:21
CPC Classifications
C; C05; C05D; C05D9/00; C05D9/02

Claims Analysis

Total Claims: 0
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References Cited (Backward Citations)

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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) 1975-02-21 1975-08-23 1976-02-22 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-02-21 1979-08-23 1980-02-22 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-02-21 1983-08-23 1984-02-22 $7700.00 Window Closed / Lapsed

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