Process for preparing metal chelates

Claim 2

A process for preparing an aqueous solution of a chelate of: (a) at least one metal selected from a first group consisting of: (i) magnesium; (ii) calcium; (iii) zinc; and (iv) manganese(II); and (b) at least one chelating agent selected from a second group consisting of moieties of: (i) ethylenediaminetetraacetic acid; (ii) nitrilotriacetic acid; (iii) diethylenetriaminepentaacetic acid; and (iv) hydroxyethylethylenediaminetriacetic acid; said process comprising: (A) forming a first admixture by admixing in an aqueous system an oxide or hydroxide of at least one member of the first group and at least one member selected from a third group consisting of: (I) a tetraalkali metal salt of ethylenediaminetetraacetic acid; (II) a trialkali metal salt of nitrilotriacetic acid; (III) a pentaalkali metal salt of diethylenetriaminepentaacetic acid; and (IV) a trialkali metal salt of hydroxyethylethylenediaminetriacetic acid; (B) admixing the first admixture and a member selected from a fourth group consisting of: (i) ethylenediaminetetraacetonitrile; (II) nitrilotriacetonitrile; and (III) diethylenetriaminepentacetonitrile to form a second admixture; (C) heating the second admixture to a temperature effective for hydrolyzing the nitrile and evaporating by-product ammonia from the second admixture, and maintaining the second admixture at this temperature for a time effective for hydrolyzing the nitrile and evaporating the by-product ammonia to form a substantially ammonia-free aqueous solution of the chelate; and (D) adjusting the pH of the resulting substantially ammonia-free aqueous solution of the chelate to about 5-9.5 and recovering the resulting product.

Claim 3

The process of claim 1 in which the chelate is a chelate of zinc.

Claim 4

The process of claim 1 in which the chelate is a chelate of manganese(II).

Claim 5

The process of claim 1 in which the chelate is a chelate of magnesium.

Claim 6

The process of claim 1 in which the chelate is a chelate of calcium.

Claim 7

The process of claim 1 in which the third group member is a tetraalkali metal salt of ethylenediaminetetraacetic acid.

Claim 8

The process of claim 1 in which the third group member is pentaalkali metal salt of diethylenetriaminepentaacetic acid.

Claim 9

The process of claim 1 in which the third group member is a trialkali metal salt of nitrilotriacetic acid.

Claim 10

The process of claim 1 in which the third group member is a trialkali metal salt of hydroxyethylethylenediaminetriacetic acid.

Claim 11

The process of claim 1 in which the second admixture is maintained at 65°-110° C. for 1-4 hours to vaporize by-product ammonia therefrom.

Claim 12

The process of claim 1 in which the second admixture boiled.

Claim 13

The process of claim 11 in which the second admixture is boiled for about 1-2.5 hours to evaporate ammonia therefrom.

Claim 14

The process of claim 1 in which the pH of the substantially ammonia-free aqueous solution of the chelate is adjusted to 6-9.

Claim 15

The process of claim 1 in which the fourth group member is ethylenediaminetetraacetonitrile.

Claim 16

The process of claim 1 in which the fourth group member is nitrilotriacetonitrile.

Claim 17

The process of claim 1 in which the fourth group member is diethylenetriaminepentaacetonitrile.

Claim 18

A process for preparing an aqueous solution of a chelate of: (a) at least one metal selected from a first group consisting of: (i) magnesium; (ii) calcium; (iii) zinc; and (iv) manganese(II); and (b) at least one chelating agent selected from a second group consisting of moieties of: (i) ethylenediaminetetraacetic acid; (ii) nitrilotriacetic acid; (iii) diethylenetriaminepentaacetic acid; and (iv) hydroxyethylenediaminetriacetic acid; said process comprising: (A) forming a first admixture by admixing in an aqueous system an oxide or hydroxide of at least one member of the first group and at least one member selected from a third group consisting of: (I) a tetraalkali metal salt of ethylenediaminetetraacetic acid; (II) a trialkali metal salt of nitrilotriacetic acid; (III) a pentaalkali metal salt of diethylenetriaminepentaacetic acid; and (IV) a trialkali metal salt of hydroxyethylethylenediaminetriacetic acid; (B) heating the first admixture to a temperature effective for: (1) hydrolyzing, in a later recited step, a nitrile selected from a fourth group consisting of: (I) ethylenediaminetetraacetonitrile; (II) nitriolotriacetonitrile; and (III) diethylenetriaminepentaacetonitrile; and (2) evaporating by-product ammonia therefrom in the later recited step; (C) admixing the heated first admixture and the fourth group member while maintaining the first admixture and the resulting second admixture at the temperature effective for: (I) hydrolyzing the nitrile; and (II) evaporating by-product ammonia from the second admixture, and maintaining the second admixture at this temperature for a time effective for hydrolyzing the fourth group member and evaporating by-product ammonia therefrom to form a substantially ammonia-free solution of the chelate; and (D) adjusting the pH of the resulting substantially ammonia-free aqueous solution of the chelate to about 5-9.5 and recovering the resulting product.

Claim 19

A process for preparing an aqueous solution of a chelate of: (a) at least one metal selected from a first group consisting of: (i) magnesium; (ii) calcium; (iii) zinc; and (iv) manganese(II); and (b) at least one chelating agent selected from a second group consisting of moieties of: (i) ethylenediaminetetraacetic acid; (ii) nitrilotriacetic acid; (iii) diethylenetriaminepentaacetic acid; and (iv) hydroxyethylenediaminetriacetic acid; said process comprising: (A) forming a first admixture by admixing in an aqueous system an oxide or hydroxide of at least one member of the first group and at least one member selected from a third group consisting of: (I) a tetraalkali metal salt of ethylenediaminetetraacetic acid; (II) a trialkali metal salt of nitrilotriacetic acid; (III) a pentaalkali metal salt of diethylenetriaminepentaacetic acid; and (IV) a trialkali metal salt of hydroxyethylethylenediaminetriacetic acid; (B) heating the first admixture to a temperature effective for: (1) hydrolyzing, in a later recited step, a nitrile selected from a fourth group consisting of: (I) ethylenediaminetetraacetonitrile; (II) nitriolotriacetonitrile; and (III) diethylenetriaminepentaacetonitrile; and (2) evaporating by-product ammonia therefrom in the later recited step; (C) admixing the heated first admixture and the fourth group member while maintaining the first admixture and the resulting second admixture at the temperature effective for: (I) hydrolyzing the nitrile; and (II) evaporating by-product ammonia from the second admixture, and maintaining the second admixture at this temperature for a time effective for hydrolyzing the fourth group member and evaporating by-product ammonia therefrom to form a substantially ammonia-free solution of the chelate; and (D) adjusting the pH of the resulting substantially ammonia-free aqueous solution of the chelate to about 5-9.5 and recovering the resulting product.