Dissymmetric n,n-dialkylamides used particularly for separating uranium(vi) from plutonium(iv), synthesis thereof and uses of same

Patent metadata

Field	Value
Publication number	US-2021332002-A1
Application number	US-201816479830-A
Country	US
Kind code	A1
Filing date	Jan 25, 2018
Priority date	Jan 26, 2017
Publication date	Oct 28, 2021
Grant date	—

Abstract

A dissymmetric RN,N-dialkylamides of formula (I) in which: R 1 represents a linear C 1 to C 4 alkyl, R 2 represents a linear C 1 to C 10 alkyl, and R 3 represents a linear or branched C 6 to C 15 alkyl, where R 3 is different from a n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R 1 represents a n-butyl group and R 2 represents an ethyl group. A method for synthesising the N,N-dialkylamides, and uses of same for extracting uranium and/or plutonium from an aqueous acid solution or for fully or partially separating the uranium from the plutonium contained in an aqueous acid solution and a solution resulting from the dissolution of spent nuclear fuel in nitric acid. A method for treating an aqueous solution resulting from the dissolution of spent nuclear fuel in nitric acid, which allows the uranium and the plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle.

First claim

What is claimed is:

1 - 19 . (canceled)

20 . An N,N-dialkylamide of formula (I):

wherein:
R 1 is a linear alkyl group having 1 to 4 carbon atoms;
R 2 is a linear alkyl group having 1 to 10 carbon atoms;
R 3 is a linear or branched alkyl group having 6 to 15 carbon atoms;

provided that R 3 differs from an n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R 1 is an n-butyl and R 2 is an ethyl group.

21 . The N,N-dialkylamide of claim 20 , wherein R 1 is a methyl, ethyl or n-propyl group.

22 . The N,N-dialkylamide of claim 20 , wherein R 2 is an n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl group.

23 . The N,N-dialkylamide of claim 20 , wherein R 3 is an n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl or 2-ethyloctyl group.

24 . The N,N-dialkylamide of claim 20 , wherein:
R 1 is a methyl group, R 2 is an n-butyl group and R 3 is an n-nonyl group; or R 1 and R 2 are each an n-propyl group and R 3 is an n-octyl group; or R 1 is an n-propyl group, R 2 is an n-pentyl group and R 3 is an n-hexyl group.

25 . A method for synthesizing an N,N-dialkylamide of formula (I):

wherein:
R 1 is a linear alkyl group having 1 to 4 carbon atoms;
R 2 is a linear alkyl group having 1 to 10 carbon atoms;
R 3 is a linear or branched alkyl group having 6 to 15 carbon atoms;

provided that R 3 differs from an n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R 1 is an n-butyl and R 2 is an ethyl group;
comprising reacting a carboxylic acid of formula (II):

wherein R 1 is a linear alkyl group having 1 to 4 carbon atoms and R 2 is a linear alkyl group having 1 to 10 carbon atoms, with an amine of formula HN(CH 3 )R 3 wherein R 3 is a linear or branched alkyl group having 6 to 15 carbon atoms, in an organic solvent and with a coupling agent; provided that R 3 differs from an n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl or 2-ethyloctyl group when R 1 is an n-butyl group and R 2 is an ethyl group.

26 . A method for extracting uranium(VI) and/or plutonium(IV) from an acid aqueous solution, comprising at least one contacting of the aqueous solution with an organic solution comprising a N,N-dialkylamide or a mixture of N,N-dialkylamides of formula (I):

wherein:
R 1 is a linear alkyl group having 1 to 4 carbon atoms;
R 2 is a linear alkyl group having 1 to 10 carbon atoms;
R 3 is a linear or branched alkyl group having 6 to 15 carbon atoms;

provided that R 3 differs from an n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R 1 is an n-butyl and R 2 is an ethyl group; in an organic diluent, followed by a separation of the aqueous solution from the organic solution.

27 . The method of claim 26 , wherein the organic solution comprises from 1 mol/L to 2 mol/L of the N,N-dialkylamide or mixture of N,N-dialkylamides.

28 . A method for separating totally or partially uranium(VI) from plutonium(IV) from an acid aqueous solution A1, comprising:
a) a co-extraction of uranium and plutonium from the aqueous solution A1, the co-extraction comprising at least one contacting of the aqueous solution A1 with an organic solution S1 comprising an N,N-dialkylamide or a mixture of N,N-dialkylamides of formula (I):

wherein:
R 1 is a linear alkyl group having 1 to 4 carbon atoms;
R 2 is a linear alkyl group having 1 to 10 carbon atoms;
R 3 is a linear or branched alkyl group having 6 to 15 carbon atoms;
provided that R 3 differs from an n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R 1 is an n-butyl and R 2 is an ethyl group; in an organic diluent, followed by a separation of the aqueous solution A1 from the organic solution S1;
b) a stripping of plutonium, in oxidation state +IV, and of a fraction of uranium from the organic solution S1 resulting from a), the stripping comprising at least one contacting of the organic solution S1 with an aqueous solution A2 comprising from 0.1 mol/L to 0.5 mol/L of nitric acid, followed by a separation of the organic solution S1 from the aqueous solution A2; and
c) an extraction of all or part of the uranium fraction contained in the aqueous solution A2 resulting from b), the extraction comprising at least one contacting of the aqueous solution A2 with an organic solution S2 identical to the organic solution S1 of a), followed by a separation of the aqueous solution A2 from the organic solution S2;
whereby there are obtained an aqueous solution comprising plutonium without uranium, or a mixture of plutonium and uranium, and an organic solution comprising uranium without plutonium.

29 . The method of claim 28 , wherein the organic solution S1 of a) comprises from 1 mol/L to 2 mol/L of the N,N-dialkylamide or mixture of N,N-dialkylamides.

30 . The method of claim 26 wherein the acid aqueous solution A1 is an aqueous solution resulting from a dissolution of a spent nuclear fuel in nitric acid.

31 . A single-cycle method for processing an aqueous solution A1 resulting from a dissolution of a spent nuclear fuel in nitric acid, the aqueous solution A1 comprising uranium, plutonium, americium, curium and fission products including technetium, the cycle comprising:
a) a co-extraction of uranium and plutonium from the aqueous solution A1, the co-extraction comprising at least one contacting, in an extractor, of the aqueous solution A1 with an organic solution S1 comprising an N,N-dialkylamide or a mixture of N,N-dialkylamides of formula (I):

wherein:
R 1 is a linear alkyl group having 1 to 4 carbon atoms;
R 2 is a linear alkyl group having 1 to 10 carbon atoms;
R 3 is a linear or branched alkyl group having 6 to 15 carbon atoms;

provided that R 3 differs from an n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R 1 is an n-butyl and R 2 is an ethyl group; in an organic diluent, followed by a separation of the aqueous solution A1 from the organic solution S1;
b) a decontamination of the organic solution S1 resulting from a) with respect to americium, curium and fission products, the decontamination comprising at least one contacting, in an extractor, of the organic solution S1 with an aqueous solution A2 comprising from 1 mol/L to 6 mol/L of nitric acid, followed by a separation of the organic solution S1 from the aqueous solution A2;
c) a partitioning of the uranium and plutonium contained in the organic solution S1 resulting from b) into an aqueous solution comprising either plutonium without uranium, or a mixture of plutonium and uranium, and an organic solution comprising uranium without plutonium, the partitioning comprising:
c 1 ) a stripping of plutonium, in oxidation state +IV, and of a fraction of uranium from the organic solution S1 resulting from b), the stripping comprising at least one contacting, in an extractor, of the organic solution S1 with an aqueous solution A3 comprising from 0.1 mol/L to 0.5 mol/L of nitric acid, followed by a separation of the o

Assignees

• Commissariat Energie Atomique
• Orano Cycle
• Electricite De France

Inventors

• Milanole Gaëlle
• Russello Emilie
• Marie Cécile
• Miguirditchian Manuel
• Sorel Christian

Classifications

• Y02P10/20

  Recycling · CPC title

• G21F9/06

  Processing (separating different isotopes of the same chemical element B01D59/00) · CPC title

• G21C19/46

  Aqueous processes {, e.g. by using organic extraction means, including the regeneration of these means} · CPC title

• C22B60/04

  Obtaining plutonium · CPC title

• C22B60/026

  liquid-liquid extraction with or without dissolution in organic solvents · CPC title