Tetraazadodecane based chelating agents for separation of rare earth elements and method therefor
AssigneeUstav Organicke Chemie A Biochemie Av Cr, V.V.I.
InventorsMiloslav Polasek, Kelsea Grace Jones, Tomas David
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Abstract
Compounds of general formula (I) for separations of rare earth elements (lanthanides) by precipitation are discussed, where R1 is selected from the group consisting of H; —CH2COOH; R2, R3, R4, R5 and R6 are independently selected from the group consisting of H; OH; —NO2; —COOH; phenyl; and/or R2 and R3 or R3 and R4 or R4 and R5, or R5 and R6 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring. Also discussed is a method of separation of rare earth elements by precipitation.
Claims18
A method for separation of rare-earth elements by precipitation, comprising the following steps:
- a) Providing an aqueous solution of ions of at least two different rare-earth elements (M3+) to be separated, and an aqueous solution of a compound of general formula (I)
- wherein
- R1 is selected from the group consisting of H and —CH2COOH;
- R2, R3, R4, R5 and R6 are independently selected from the group consisting of —H, OH, —NO2, —COOH, and phenyl;
- and/or R2 and R3 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring;
- and/or R3 and R4 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring;
- and/or R4 and R5 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring;
- and wherein R5 and R6 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring;
- and
- a solvent selected from the group consisting of water, buffer, and mixture of water and organic solvent miscible with water, wherein the water content is at least 50 vol. %;
- b) Reaction of the aqueous solution of ions of at least two different rare-earth elements (M3+) to be separated with the aqueous solution of the compound of general formula (I), at pH in the range of from 5 to 9, and a mixing time of at least 1 minute, to form at least one complex of the M3+ ion with the compound of general formula (I) in the form of a precipitate or a crystalline phase;
- and
- c) Mechanical separation of the precipitate or of the crystalline phase from the reaction mixture using sedimentation, centrifugation, or filtration.
A method for separation of rare-earth elements by precipitation, comprising:
- providing an aqueous solution comprising ions of at least two different rare-earth elements;
- and
- contacting the aqueous solution with a compound of general formula (I) to precipitate a complex of at least one of the at least two rare-earth elements with a compound selected from the group consisting of
- 2,2′,2″-(10-benzyl-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid;
- 2,2′-(4-(2-hydroxy-5-nitrobenzyl)-1,4,7,10-tetraazacyclododecane-1,7-diyl)diacetic acid;
- 2,2′-(4-(4-carboxybenzyl)-1,4,7,10-tetraazacyklododekane-1,7-diyl)diacetic acid;
- and
- 2,2′,2″-(10-([1,1′-biphenyl]-4-ylmethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid
- or with the compound of general formula (I), wherein the compound of general formula (I) has the following structure:
- wherein
- R1 is selected from the group consisting of H and —CH2COOH;
- R2, R3, R4, R5 and R6 are independently selected from the group consisting of —H, OH, —NO2, —COOH, and phenyl;
- and wherein R2 and R3 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring;
- and/or R3 and R4 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring;
- and/or R4 and R5 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring;
- and/or R5 and R6 together with two neighbouring carbon atoms of the aromatic ring form a six-membered aromatic ring.
Dependencies are inferred from the claim text.