Aminocarboxylate powders with improved purity and flowability properties
AssigneeDow Global Technologies LLC
InventorsJ. Weldon Moore, Jr., Steven T. Booth, Ray O. Leenhouts
Life of this patent
Estimating the term…
Abstract
Provided is a method for preparing stable free flowing solid aminocarboxylate chelants by adding to a chelant that contains residual alkaline metal hydroxide a free or partially neutralized carboxylic acid such that the free or partially neutralized acid neutralizes at least a portion of the alkaline metal hydroxide; and isolating therefrom the free-flowing solid chelant.
Claims9
A method for producing a free-flowing solid aminocarboxylate chelant, the method comprising:
- (a) providing a solution comprising the aminocarboxylate chelant and residual alkaline metal hydroxide;
- (b) adding to the solution a free or partially neutralized carboxylic acid such that the free or partially neutralized acid neutralizes at least a portion of the residual alkaline metal hydroxide;
- and
- (c) isolating therefrom the free-flowing solid aminocarboxylate chelant, wherein the amount of free or partially neutralized carboxylic acid added in step (b) is such that no more than 5% by weight of the aminocarboxylate chelant is acidified.
A method for producing free-flowing solid ethylenediamine-N,N,N′,N′-tetraacetic acid tetrasodium salt (Na4EDTA), the method comprising:
- (a) providing a solution comprising the ethylenediamine-N,N,N′,N′-tetraacetic acid tetrasodium salt and residual sodium hydroxide;
- (b) adding to the solution ethylenediamine-N,N,N′,N′-tetraacetic acid or a partial salt thereof such that at least a portion of the residual sodium hydroxide is neutralized;
- and
- (c) isolating therefrom the free-flowing solid ethylenediamine-N,N,N′,N′-tetraacetic acid tetrasodium salt by crystallization or spray-drying,
- wherein the amount of ethylenediamine-N,N,N′,N′-tetraacetic acid or a partial salt thereof added in step (b) is such that no more than 5% by weight of the ethylenediamine-N,N,N′,N′-tetraacetic acid tetrasodium salt is acidified.
Dependencies are inferred from the claim text.