Salts, crystals, complexes, and derivatives of threonine diacetic acid, a process to prepare threonine diacetic acid, and the use thereof
View Patent ↗The present invention relates to new salts, complexes, crystals, solutions, dispersions, and slurries of threonine-N,N-diacetic acid or derivatives thereof, to formulations containing those, to processes to prepare those, and to the use thereof.
1. A process to prepare threonine-N,N-diacetic acid or a salt thereof comprising two or more steps wherein in a first step threonine, a sodium or potassium salt thereof or a mixture thereof is reacted with formaldehyde and hydrogen cyanide, at a pH equal to or below 7 to form a nitrile compound, and in a second step the nitrile compound formed in the first step is hydrolyzed by the addition of an acid or base.
2. A process to prepare threonine-N,N-diacetic acid or a salt thereof comprising reacting threonine, a sodium or potassium salt thereof or a mixture thereof with formaldehyde, hydrogen cyanide, a potassium or sodium salt thereof or a mixture thereof, and potassium hydroxide, sodium hydroxide or a mixture thereof, in an aqueous solution at an alkaline pH and at an elevated temperature to remove formed NH 3 .
3. A process to prepare threonine-N,N-diacetic acid or a salt thereof, wherein threonine is reacted with a monohaloacetic acid at a temperature of 20 to 80° C. and an alkaline pH.
4. The process of claim 1 wherein said nitrile compound is threonine-N,N-diacetonitrile or a salt thereof.
5. The process of claim 1 wherein subsequent to the hydrolysis step an acidification step is performed.
6. The process of claim 2 wherein subsequent to the reaction at alkaline pH an acidification step is performed.
7. The process of claim 3 wherein said monohaloacetic acid is monochloroacetic acid.
8. The process of claim 3 wherein the reaction product is a salt of threonine-N,N-diacetic acid and a subsequent acidification step is performed to convert the salt formed into the acid.
9. A composition comprising a compound selected from the group consisting of
a complex of threonine-N,N-diacetic acid and a divalent or trivalent cation, wherein the cation is selected from the group of calcium, magnesium, iron, zinc, manganese, aluminium, copper, and cobalt; and
a salt of threonine-N,N-diacetic acid of the formula CH 3 —CHOH—C(H)(COOM)-N—(CH 2 —COOM) 2 , wherein at least one M is chosen from the group of sodium, potassium, lithium, cesium, and ammonium.
10. The composition of claim 9 wherein said compound is in crystalline form.
11. The composition of claim 9 wherein said composition is a formulation comprising a liquid.
12. The composition of claim 11 wherein the liquid is water.