Patent Number: 
Section: claims

1. A compound of general formula (I) below:where:m is an integer of 0, 1 or 2;R1 and R2, the same or different, are a saturated or unsaturated, straight-chain or branched hydrocarbon group having 6 to 12 carbon atoms;R3 is:a saturated or unsaturated, straight-chain or branched hydrocarbon group having 1 to 12 carbon atoms and optionally one or more heteroatoms;a saturated or unsaturated, monocyclic hydrocarbon group having 3 to 8 carbon atoms and optionally one or more heteroatoms; ora monocyclic aryl or heteroaryl group;or else R2 and R3 together form a —(CH2)n— group wherein n is an integer from 1 to 4;R4 is a saturated or unsaturated, straight-chain or branched hydrocarbon group having 2 to 8 carbon atoms, or a monocyclic aromatic group; andR5 is a hydrogen atom or a saturated or unsaturated, straight-chain or branched hydrocarbon group having 1 to 12 carbon atoms. 2. The compound of claim 1 wherein the compound is of particular formula (I-a) below:wherein:m, R1, R4 and R5 are such as previously defined;R2 is a saturated or unsaturated, straight-chain or branched hydrocarbon group having 6 to 12 carbon atoms; whilstR3 is:a saturated or unsaturated, straight-chain or branched hydrocarbon group having 1 to 12 carbon atoms and optionally one or more heteroatoms;a saturated or unsaturated, monocyclic hydrocarbon group having 3 to 8 carbon atoms and optionally one or more heteroatoms; ora monocyclic aryl or heteroaryl group. 3. The compound of claim 2, wherein R1 and R2, the same or different, are a straight-chain or branched alkyl group having 6 to 12 carbon atoms. 4. The compound of claim 3, wherein R1 and R2 are the same and each are a branched alkyl group having 8 to 10 carbon atoms. 5. The compound of claim 4, wherein R1 and R2 are a 2-ethylhexyl group. 6. The compound of claim 2, wherein m equals 0. 7. The compound of claim 2, wherein R3 is a straight-chain or branched alkyl group having 1 to 12 carbon atoms, or a monocyclic aromatic group. 8. The compound of claim 2, wherein R5 is a hydrogen atom. 9. The compound of claim 7, wherein R3 is a methyl group, an n-octyl group or a phenyl group. 10. The compound of claim 2, wherein R4 is a straight-chain or branched alkyl group having 2 to 8 carbon atoms. 11. The compound of claim 10, wherein R4 is a straight-chain or branched alkyl group having 2 to 4 carbon atoms. 12. The compound of claim 11, wherein R4 is an ethyl group or an n-butyl group. 13. The compound of claim 2, wherein the compound is:Ethyl 1-(N,N-diethylhexylcarbamoyl)benzylphosphonate, wherein m equals 0, R1 and R2 each are a 2 ethylhexyl group, R3 is a phenyl group, R4 is an ethyl group and R5 is a hydrogen atom;Ethyl 1-(N,N-diethylhexylcarbamoyl)ethylphosphonate, wherein m equals 0, R1 and R2 each are a 2-ethylhexyl group, R3 is a methyl group, R4 is an ethyl group and R5 is a hydrogen atom;Ethyl 1-(N,N-diethylhexylcarbamoyl)nonylphosphonate, wherein m equals 0, R1 and R2 each are a 2 ethylhexyl group, R3 is an n-octyl group, R4 is an ethyl group and R5 is a hydrogen atom;Butyl 1-(N,N-diethylhexylcarbamoyl)nonylphosphonate, wherein m equals 0, R1 and R2 each are a 2 ethylhexyl group, R3 is an n-octyl group, R4 is an n-butyl group and R5 is a hydrogen atom; orButyl 1-(N,N-dioctylcarbamoyl)nonylphosphonate, wherein m equals 0, R1, R2 and R3 each are an n-octyl group, R4 is an n-butyl group and R5 is a hydrogen atom. 14. The compound of claim 13, which is ethyl 1-(N,N -diethylhexylcarbamoyl)nonylphosphonate or butyl 1-(N,N-diethylhexylcarbamoyl)nonyl-phosphonate. 15. The compound of claim 1, wherein the compound is of particular formula (I-b):wherein m, n, R1, R4 and R5 are such as previously defined. 16. The compound of claim 15, wherein R1 is a straight-chain or branched alkyl group having 6 to 12 carbon atoms. 17. The compound of claim 15, wherein m equals 0, R4 is a straight-chain or branched alkyl group having 2 to 8 carbon atoms and R5 is a hydrogen atom. 18. The compound of claim 15, which is ethyl (N-dodecylpyrrolidone)-1-phosphonate wherein m=0, n=2, R1 is an n-dodecyl group, R4 is an ethyl group and R5 is a hydrogen atom. 19. A method for extracting uranium(VI) from an aqueous solution of phosphoric acid, comprising contacting the aqueous solution with an organic phase comprising a compound of general formula (I) below:where:m is an integer of 0, 1 or 2;R1 and R2, the same or different, are a saturated or unsaturated, straight-chain or branched hydrocarbon group having 6 to 12 carbon atoms;R3 is:a saturated or unsaturated, straight-chain or branched hydrocarbon group having 1 to 12 carbon atoms and optionally one or more heteroatoms;a saturated or unsaturated, monocyclic hydrocarbon group having 3 to 8 carbon atoms and optionally one or more heteroatoms; ora monocyclic aryl or heteroaryl group;or else R2 and R3 together form a —(CH2)n— group wherein n is an integer from 1 to 4;R4 is, a saturated or unsaturated, straight-chain or branched hydrocarbon group having 2 to 8 carbon atoms, or a monocyclic aromatic group; andR5 is a hydrogen atom or a saturated or unsaturated, straight-chain or branched hydrocarbon group having 1 to 12 carbon atoms, and then separating the aqueous solution from the organic phase. 20. The method of claim 19, wherein the aqueous solution contains 0.01 to 9 mol/L of phosphoric acid. 21. The method of claim 20, wherein the aqueous solution is derived from the digestion of a natural phosphate with sulphuric acid. 22. A method for recovering uranium contained in an aqueous solution of phosphoric acid derived from the digestion of a natural phosphate with sulphuric acid, comprising:a) extracting the uranium, in oxidation state VI, from the aqueous solution of phosphoric acid by contacting the aqueous solution with an organic phase comprising a compound of general formula (I) below:where:m is an integer of 0, 1 or 2;R1 and R2, the same or different, are a saturated or unsaturated, straight-chain or branched hydrocarbon group having 6 to 12 carbon atoms;R3 is:a saturated or unsaturated, straight-chain or branched hydrocarbon group having 1 to 12 carbon atoms and optionally one or more heteroatoms;a saturated or unsaturated, monocyclic hydrocarbon group having 3 to 8 carbon atoms and optionally one or more heteroatoms; ora monocyclic aryl or heteroaryl group;or else R2 and R3 together form a —(CH)n— group wherein n is an integer from 1 to 4;R4 is, a saturated or unsaturated, straight-chain or branched hydrocarbon group having 2 to 8 carbon atoms, or a monocyclic aromatic group; andR5 is a hydrogen atom or a saturated or unsaturated, straight-chain or branched hydrocarbon group having 1 to 12 carbon atoms such as defined in claim 1, then by separating the aqueous solution from the organic phase;b) washing the organic phase obtained at the end of step a);c) stripping the uranium(VI) contained in the organic phase obtained at the end of step b) by contacting the organic phase with an aqueous solution comprising a carbonate, then separating the organic phase and the aqueous solution; and optionally:d) acidifying the organic phase obtained at the end of step c) by contacting the organic phase with an acid aqueous solution. 23. The method of claim 22, wherein the compound is used in solution, at a concentration of 0.01 to 1 mol/L, in an organic diluent. 24. The method of claim 22, or claim 21, wherein the aqueous solution of phosphoric acid comprises 0.01 to 9 mol/L of phosphoric acid. 25. The method of claim 22, wherein the aqueous solution comprising the carbonate comprises 0.1 to 1.5 mol/L of carbonate.