OA18460A - Use of new compounds for the selective extraction of rare earths from aqueous solutions comprising phosphoric acid and associated extraction process - Google Patents

Abstract

The invention relates to the use as an extractant, for extracting at least one rare earth from an aqueous phase comprising phosphoric acid, of at least one compound which corresponds to the following general formula (I) : in which n represents an integer equal to 0, 1 or 2, R1 and R2 represent H or an aliphatic hydrocarbon group, one of R3 and R4 corresponds to the following formula (II): in which R5 and Re represent a group hydrocarbon, hydroxyl or alkoxyl, and the other of R3 and R4 has one of the following formulas (II ') and (III): with R5' and R6 'represent a hydrocarbon, hydroxyl or alkoxyl group, and R7 and R8 represent H or an aliphatic hydrocarbon group. The invention also relates to a process for recovering at least one rare earth using this compound as well as to particular compounds as such.

Description

TECHNICAL AREA

The present invention relates to the field of the extraction of rare earths from acidic aqueous phases in which said rare earths are present.

It relates more particularly to the use of at least one specific compound as an extractant, to extract at least one rare earth from an acidic aqueous phase in which said at least one rare earth is present.

The invention also relates to a process for recovering at least one rare earth present in an acidic aqueous phase, said process using this specific compound.

The acidic aqueous phase from which can be extracted, or from which can be recovered, the rare earth (s) is an aqueous solution comprising phosphoric acid. Such an aqueous solution may in particular be an acid attack solution of an ore or waste concentrate comprising said at least one rare earth.

The present invention finds application in particular in the treatment of natural ores and / or industrial waste with a view to upgrading the rare earths present in the latter.

Finally, the present invention relates to certain specific compounds the use of which is mentioned above.

STATE OF THE PRIOR ART

Rare earths include metals characterized by similar properties, namely scandium (Sc), yttrium (Y) as well as all the lanthanides, the latter corresponding to the chemical elements listed in the periodic table of the elements of Mendeleîev. which have an atomic number ranging from 57 for lanthanum (La) to 71 for lutetium (Lu).

Rare earths are generally classified in two categories: cerlques earths, or light rare earths, which include Sc, Y as well as metals ranging from lanthanum (La) to neodymium (Nd), and heavy rare earths, or yttric group, which include metals ranging from promethium (Pm) to lutetium (Lu).

The similar properties of rare earths are in particular linked to their electronic configuration, in particular to the specificity of their electronic sub-layer 4f which allows numerous optical transitions and gives them particular magnetic and catalytic properties. Due to these remarkable properties, rare earths are used in many high-tech applications such as lasers, permanent magnets, batteries or even low-consumption light bulbs.

Rare earths are therefore part of the so-called technological metals whose supply is strategic, but also threatened by the effect of the growth in world demand for these particular metals.

Sources of rare earths include hard rock deposits of bastnaesite as well as alluvial deposits of monazite and xenolith. Besides these ores which contain the highest concentrations of rare earths, we can also mention other ores, such as phosphate ores or apatltes, admittedly poorer in lanthanldes, but whose exploitation and processing in the future can be profitable. In the remainder of the present description, the ores which have just been cited and which contain rare earths in greater or lesser quantities are designated by the expression of natural ores.

As rare earths are also present in a large number of technological equipment, the recovery by recycling of industrial waste from such equipment, and in particular from waste electrical and electronic equipment, denoted WEEE or D3E, represents an unconventional source and alternative access to rare earths. In the remainder of the present description, these Industrial wastes which contain rare earths are designated by the expression “Industrial ores”.

The processes currently used for recovering the rare earths from these natural or industrial ores consist in subjecting these ores, previously crushed, to chemical treatments, with acidic or basic reagents, in order to obtain a mineral concentrate.

This mineral concentrate is then subjected to chemical attack to allow the rare earths contained therein to be dissolved. This chemical attack is conventionally carried out by means of one or more acid reagents including nitric acid, sulfuric acid, phosphoric acid or hydrochloric acid.

The so-called adde etching solution thus obtained is then subjected to a hydro-metallurgical treatment based on the liquid-liquid extraction technique, a technique which consists in bringing the aqueous phase constituted by this acid etching solution into contact with an organic phase. comprising one or more extradants, in order to obtain an extraction of rare earths, such an extraction having to be, preferably, simultaneously efficient and selective.

Among the extradants used industrially for the extraction of rare earths, mention may be made of ô / s- (2-ethylhexyi) phosphoric acid (or HDEHP), 2ethylhexyi-2-ethylhexylphosphonic acid (or HEHEHP) as well as phosphate of tri-n-butyie (or TBP), the TBP being the extraditor the most used to date.

In addition to the fact that HDEHP allows extraction of rare earths present in a strongly acidic aqueous phase (pH <1) while HEHEHP allows extraction of rare earths present in an additional aqueous phase having a 2 <pH <3, these three HDEHP, HEHEHP and TBP extraditors are characterized by a selective extradion of heavy lanthanldes corresponding to lanthanldes with an atomic number of 61 or more (up to 71).

The use of such extradants therefore does not make it possible to extract all of the rare earths, but only the heavy rare earths. In addition, setting t

implementation of the extradants HDEHP and HEHEHP Imposes determined ranges of concentration of the acid present in the aqueous phase.

A recent publication by S. Ansari et al. (Chemistry of Diglycolamides: Promlslng Extradants for Adlnlde Partitioning, Chemical Revlews, 2012, 112, 1751-1772), referenced [1] at the end of the present description, describes the use of diglycolamides (or DGA), among which the N , N, N ', N-tetra-n-odyldiglycolamide (or TODGA), as compounds suitable for the extraction of lanthanides and actinides present in an aqueous phase comprising nitric acid.

However, the publication [1] reports that the extraction by TODGA can generate the formation of a third phase, which is prohibitive for an implementation on an industrial scale of an extraction process. To remedy the formation of this third phase, the publication [1] suggests associating TODGA with a phase modifier, in this case TBP. In such a configuration, there is therefore no longer one but two extraditors to implement. However, such a system with two extraditors, which requires in particular the determination of an optimal ratio of the latter, is of course more difficult to manage than a system with only one extraditor.

In the even more recent publication by H. Narita et al. (Separation of Rare Earth Elements from Base Metals In Concentrated HNO3, H2SO4 ond HCl Solutions with Diglycolamlde, Solvent Extradion Research and Development, Japan, 2013, 20, 115-121), referenced [2], the authors describe the use of N , W'-dimethyl-N, N'-di-noctyldiglycolamide (or MODGA) as extraditing neodymium Nd (III) and dysprosium Dy (III) present in aqueous solutions comprising, in addition, iron Fe (III), nickel Ni (li) and variable molar concentrations ranging between 0.1 mol / L and 7 mol / L of nitric acid, hydrochloric acid or even sulfuric acid. According to the experimental results presented in this publication [2], the most efficient and effective extradion of Nd and Dy, compared to Fe and Ni, is obtained with aqueous solutions comprising nitric acid. .

If the extraction by diglycolamides of rare earths from acidic aqueous phases is known from publications [1] and [2], it is however observed that only the extraction from aqueous phases comprising hydrochloric acid, acid sulfuric or, more broadly, nitric acid has been described.

However, and as illustrated in Example 8 below, the Inventors have observed that the extraction performance described in publication [1], with TODGA as extradant and the extraction being carried out from an aqueous phase comprising nitric acid, were not transposable to an extraction carried out from an aqueous phase comprising phosphoric acid.

It is on the basis of this observation that the Inventors have therefore set themselves the goal of providing a new family of extractants which have a high affinity for all or part of the rare earths and which, consequently, allow them to be used for extracting at least one rare earth from an acidic aqueous phase in which this or these rare earths are present, this acidic aqueous phase comprising, as acid, phosphoric acid and not nitric, hydrochloric or sulfuric acid.

The extraction by means of this new family of extractants must be able to make it possible to extract the major part of the rare earths present in the aqueous phase or, on the contrary, some of these rare earths, for example according to their atomic number. The extraction by means of these extradants should also tend to be selective with respect to the elements which are also likely to be present in the acidic aqueous phase but which are not rare earths.

The inventors have also set themselves the goal that this extraction can be advantageously carried out in a range of phosphoric acid concentrations in the aqueous phase which is as wide as possible.

The inventors have also set themselves the goal that this extraction can be advantageously carried out with a single extradant and this, without a third phase forming, thus making it possible to favorably consider a transposition to an industrial scale of the process. 'corresponding extraction.

DISCLOSURE OF THE INVENTION

The aforementioned goals as well as others are achieved, firstly, by the use of at least one particular compound as an extradant, to extract at least one rare earth from an aqueous phase in which said at least one rare earth is present, said aqueous phase further comprising phosphoric acid.

This particular compound, the use of which is the subject of the present invention, is a compound which corresponds to the following general formula (I):

in which

- n represents an integer equal to 0.1 or 2,

- Ri and R ₂ represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, C 1 to C ₂ hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group , optionally branched, C ₃ to Ca,

- one among R ₃ and R4 corresponds to the following formula (II):

O

in which Rs and R6 represent. Independently of one another, an aliphatic, saturated or unsaturated, linear or branched, C 1 to C ₂ hydrocarbon group, a cyclic, saturated or unsaturated hydrocarbon group, optionally branched, C ₃ to Ca, a hydroxyl group - OH or an alkoxyl group -OR, with R representing an aliphatic, saturated or unsaturated, linear or branched, C 1 to C 12 hydrocarbon group or a cyclic, saturated or unsaturated, optionally branched, C 1 to C 18 aliphatic hydrocarbon group, and the other among R ₃ and R <answers:

. either to the following formula (ΙΓ):

t

(II) in which Rs 'and Re' represent, independently of one another, an aliphatic, saturated or unsaturated, linear or branched, C1 to Cn hydrocarbon group, a cyclic, saturated or unsaturated hydrocarbon group, optionally branched, C3 to C6, a hydroxyl group -OH or an alkoxyl group -OR ', with R' representing an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group or a cyclic, saturated or aliphatic hydrocarbon group Unsaturated, possibly branched, in C3 to Ce,. either to the following formula (III):

O II in which R7 and Rs represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group or a cyclic, saturated or aliphatic hydrocarbon group unsaturated, optionally branched, C3 to Cs.

In what precedes and in what follows, is meant by:

- Aliphatic hydrocarbon group, saturated to unsaturated, linear to branched, C 1 to C 12 ⁿ , any alkyl, alkenyl or alkynyl group, linear or branched, which comprises in total from 1 to 12 carbon atoms;

- cyclic, saturated or unsaturated, optionally branched, C3 to Cg aliphatic hydrocarbon group, any non-aromatic hydrocarbon group comprising at least one ring, said ring comprising from 3 to 8 carbon atoms, this ring possibly being saturated or, on the contrary,

I comprise one or more unsaturations, this or these ring (s) also possibly being branched, the branched chain (s) then comprising from 1 to 6 carbon atoms. Thus, this group can in particular be a cycloalkyl group (cyclopropane, cyclopentane, cyclohexane, etc.), a cydoalkenyl group (cydopropenyl, cydopentenyl, cyclohexenyl, etc.) or else a cycloalkynyl group;

- cyclic, saturated or unsaturated, optionally branched, Cj to Cs hydrocarbon group, any non-aromatic hydrocarbon group comprising at least one ring as defined in the preceding paragraph as well as any aromatic hydrocarbon group comprising at least one ring, this ring comprising from 3 to 8 carbon atoms and complying with Huckel's aromatlclté rule with a number of delocalized π electrons equal to 4n + 2. This or these rings can also be branched, the branched chain or chains then comprising 1 with 6 carbon atoms. Thus, this group can in particular be a cycloalkyl group, a cydoalkenyl group, a cycloalkynyl group or else a cycloaromatic group such as a phenyl or benzyl group.

In addition, the expression from ... to ... which has just been used to define the Intervals and which is used in the remainder of the present application, must be understood as defining not only the values of the interval, but also the values of the limits of this interval.

The inventors have in fact observed that, surprisingly and unexpectedly, the use of the compounds corresponding to general formula (I) above makes it possible to extract, in a high-performance and selective manner, at least one rare earth present, and advantageously at least one lanthanide present, in an aqueous solution comprising, in addition, phosphoric addde.

However, if some of the compounds corresponding to general formula (I) above have already been the subject of extraction tests, as reported in the publication, referenced [3J, by M. Iqbal et al. (Synthesis and evaluation of ligands with mixed amide and phosphonate, phosphinoxide, and phosphonothioate sites for An (III) / Ln (III) extraction ”, New J. Chem., 2012, 36, 2048-2059), these extractions were carried out under conditions similar to those described in publications [1] and [2], namely from aqueous phases comprising nitric acid, and not from phosphoric acid.

In an advantageous version, the compound of general formula (I), the use of which is the subject of the present invention is the compound in which n = 0 and which corresponds to the following general formula (I ¹ ):

Ri ^R 2 in which Ri, R2, R3 and R4 are as defined above.

In a first more particularly advantageous version, the present invention relates to the use of the compound which corresponds to the following particular formula (l-a):

O O li II

^R 6 ^R ! ^R 2 in which R1, R2, Rs, Rs, Rs * and Rs' are as defined above, it being specified that Rs and / or Re represent a hydroxyl group —OH.

Preferably, in the particular formula (1-a) above:

- one of Rs and Re represents a hydroxyl group -OH and the other of Rs and Re represents an alkoxyl group -OR, with R representing an alkyl group, linear or branched, C2 to Cs, advantageously C4, and

- Rs * and Re represent, independently of one another, an alkyl group, linear or branched, C4 to C10, advantageously C ".

The compound of particular formula (Ia) in which Rs, Rs, Rs * and Rs * are as they have just been defined above, corresponds to a bifunctional compound comprising a phosphinate group -PO (OH) (OR) and a phosphine oxide group -PORs'Rs *.

Also preferably, in the particular formula (1-a) above, and according to a first variant, R 1 and R 2 each represent a hydrogen atom.

î

As demonstrated in Example 9 below, the use of such a bifunctional compound comprising a phosphinate group and a phosphine oxide group and in which R 1 = R ₂ = H makes it possible to extract the heavy rare earths (such as ytterbium Yb) in an efficient and particularly selective manner, whether with respect to rare earths with a lower atomic number (such as La, Nd, Gd and Dy) or impurities (represented in all the examples by Fe) and this , regardless of the concentration of phosphoric acid.

Also preferentially, in the particular formula (Ia) above, and according to a second variant, at least one of R 1 and R 2 represents an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C .

Thus, and according to a first aspect of this second variant, in the particular formula (Ia) above, R 1 and R ₂ each represent an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C 6.

According to a second aspect of this second variant, in the particular formula (la) above, one of R 1 and R 2 represents a hydrogen atom and the other of R 1 and R ₂ represents an alkyl group, linear or branched , in Ci to Cio, advantageously in Ci to Ce.

In a second more particularly advantageous version, the present invention relates to the use of the compound which corresponds to the following particular formula (1-b):

^ γΎΎ ’-h’

Re r _x Rj r ₈ in which Ri, R ₂ , Rs, Rs, R7 and Rs are as defined above, it being specified that R _s and / or Rs represent a hydroxyl group —OH.

Preferably, in the particular formula (1-b) above:

- one from Rs and Re represents a hydroxyl group -OH and the other from Rs and Re represents an alkyl group, linear or branched, C4 to Cio, advantageously in Ce or an alkoxyl group -OR, with R representing a alkyl group, linear or branched, C2 to Ce, advantageously C4, and

- R7 and Rs preferably represent, independently of one another, an alkyl group, linear or branched, in Q to Cio, advantageously in C ».

Thus, in the case where one of Rs and Rs represents -OH, the other of R5 and R6 represents an alkyl group, linear or branched as specified above and that R7 and Rs are as defined above , the compound of particular formula (lb) corresponds to a bifunctional compound comprising a phosphinate group -PO (OH) Rs or -PO (OH) Rs and an amide group -COR7R8.

Thus, in the case where one of R5 and R6 represents -OH, the other of Rs and R6 represents an alkoxyl group -OR as specified above and that R7 and Rs are as defined above, the compound of particular formula (lb) corresponds to a bifunctional compound comprising a phosphonate group -PO (OH) (OR) and an amide group -COR7R8.

Also preferably, in the particular formula (1-b) above, and according to a first variant, R 1 and R 2 each represent a hydrogen atom.

As demonstrated in Examples 11 and 12 below, the use of such a bifunctional compound comprising a phosphonate group and an amide group and in which R 1 = R 2 = H makes it possible to extract, in a grouped manner, all of the heavy rare earths tested (Gd, Dy and Yb) as well as certain light rare earths (Nd, but not La), whatever the concentration of phosphoric acid in the aqueous phase, the extraction of Yb also being particularly selective with respect to impurities (Fe).

Also preferentially, in the particular formula (lb) above, and according to a second variant, at least one of R 1 and R 2 represents an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C 8 .

Thus, and according to a first aspect of this second variant, in the particular formula (1-b) above, R 1 and R 2 each represent an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C 6.

According to a second aspect of this second variant, in the particular formula (lb) above, one of R 1 and R 2 represents a hydrogen atom and the other of R 1 and R 2 represents an alkyl group, linear or branched, in Ci to Cio, advantageously in Ci to Ce.

According to the second aspect of this second variant, the compound of particular formula (Ib), the use of which is the subject of the present invention may comprise an alpha branching of the ether, either on the side of the phosphonate group (in which case R2 = H), or on the side of the amid group (in which case Ri = H).

According to this second aspect, the compound of particular formula (i-b) is advantageously that in which R2 represents a hydrogen atom.

Typically, and with reference to what has just been described, the compounds corresponding to the general formula (I) and, among these, the compounds corresponding to the particular formulas (la) and (lb), are used, in accordance with the present invention, as extractants for extracting at least one rare earth from an aqueous phase in which said at least one rare earth is present, said aqueous phase further comprising phosphoric acid.

According to an advantageous variant of the invention, the aqueous phase is an acid attack solution, typically with one or more inorganic acids, of a concentrate of a natural or urban mineral comprising said at least one rare earth. The presence of phosphoric acid in this acid attack solution results from the use of phosphoric acid as an inorganic acid and / or from its formation in situ given the presence of precursors of such an acid, such as natural phosphates.

It should be remembered that urban ore can in particular come from the recycling of industrial waste such as waste electrical and electronic equipment (D3E).

t

According to another advantageous variant of the invention, the aqueous phase comprises at least 0.1 mol / L, advantageously from 0.2 mol / L to 8 mol / L, and preferably from 0.5 mol / L to 5 mol / L, phosphoric acid.

According to another advantageous variant of the invention, the extraction is carried out by the liquid-liquid extraction technique, a technique which brings this aqueous phase comprising the rare earth (s), advantageously the lanthanide (s), and the acid into contact. phosphoric with an organic phase comprising one or more of these compounds mentioned above, preferably only one of these compounds.

According to another advantageous variant of the invention, this liquid-liquid extraction is carried out by means of an organic phase comprising at least 1d ³ mol / L, advantageously from 5.10 ³ mol / L to 1 mol / L, and preferably from 10 ² mol / L to 10 * ¹ mol / L, of the compound dissolved in an organic diluent.

This organic diluent is advantageously of the aliphatic type, and can in particular be n-docedane, hydrogenated tetrapropylene (TPH), kerosene or an isoparaffin such as risane * IP 185 sold by the company Total.

The present invention relates, secondly, to a process for recovering at least one rare earth present, and advantageously at least one lanthanum present, in an aqueous phase, said aqueous phase comprising, in addition, Phosphoric acid.

According to the invention, this recovery process comprises the following steps:

a) the extraction of said at least one rare earth, advantageously of said at least one lanthanide, from the aqueous phase by bringing the aqueous phase into contact with an organic phase comprising at least one compound as defined above, then separation of the aqueous phase of the organic phase; and

b) the back-extraction of said at least one rare earth element present, advantageously of said at least one lanthanide present, in the organic phase as obtained at the end of step a) by bringing this organic phase into contact with a phase aqueous, then separation of the organic phase from the aqueous phase.

t

In step a) of this process according to the invention, the compound present in the organic phase is the compound as defined above, it being specified that the advantageous characteristics of this compound can be taken alone or in combination.

Likewise, the aqueous and organic phases used during step a) of the process according to the invention may be as defined above, in relation to the use of the compound, and may have the advantageous characteristics. described above for these aqueous and organic phases, alone or in combination.

In an advantageous variant of the process according to the invention, during step a), at least one salt is added to the aqueous phase, such as a nitrate or sulphate salt of an alkali or alkaline metal. earthy, which increases the ionic strength of this aqueous solution.

The introduction of such a salt has the effect of increasing the performance of the extraction for all rare earths (see examples 11 and 12 below).

Such a salt can in particular be chosen from sodium, lithium or potassium nitrate. This salt is advantageously sodium nitrate.

the molar concentration of inductors), in the aqueous phase, is from 0.01 mol / L to 4 mol / L, advantageously from 0.05 mol / L to 3 mol / L and, preferably, from 0.1 mol / L at 2 mol / L

In an advantageous variant of the process according to the invention, the aqueous phase implemented during step a) is an acid attack solution, by phosphoric acid, of a concentrate of a natural or urban mineral comprising said at least one rare earth.

The present invention relates, thirdly, to particular compounds which, to the knowledge of the inventors, have not been described to date.

In a first version, the compound according to the invention corresponds to the following particular formula (1-a):

"

Ο Ο ^R s / ^P Y ⁰ Y ^P r ^R s ' ^(, ' ^{a) R} s Ri R ₂ «6 * in which

- Ri and Rz represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group, optionally branched, in C3 to Ce,

- one of Rs and R6 represents a hydroxyl group —OH and the other of Rs and R6 represents an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group, a cyclic, saturated or unsaturated hydrocarbon group, optionally branched, C 3 to C 8, a hydroxyl group -OH or an alkoxyl group -OR, with R representing an aliphatic, saturated or unsaturated, linear or branched, C 1 to C 12 hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group , optionally branched, in C3 to Cs, and

- Rs' and Rs * represent, independently of one another, an aliphatic, saturated or unsaturated, linear or branched, C 1 to C 12 hydrocarbon group, a cyclic, saturated or unsaturated, optionally branched, C 3 to C hydrocarbon group. Cs, a hydroxyl group -OH or an alkoxyl group -OR ', with R' representing an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group or a cyclic, saturated or unsaturated, optionally branched aliphatic hydrocarbon group, in C3 to Cs.

Preferably, in the particular formula (1-a) above:

- one of Rs and Re represents a hydroxyl group -OH and the other of Rs and R6 represents an alkoxyl group -OR, with R representing an alkyl group, linear or branched, C2 to Cs, advantageously C4, and

- Rs 'and R ₆ ' represent, independently of one another, an alkyl group, linear or branched, C4 to Cio, advantageously Cs.

As already indicated previously, the compound of particular formula (l-a) in which Rs, R6, Rs * and Re * are as they have just been defined above

above, corresponds to a bifunctional compound comprising a phosphonate group -PO (OH) (OR) and a phosphlne oxide group -PORs'Re *.

Also preferably, in the particular formula (ia) above, and according to a first variant, R 1 and R ₂ each represent a hydrogen atom.

Also preferably, in the particular formula (ia) above, and according to a second variant, at least one of R 1 and R ₂ represents an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to This.

Thus, and according to a first aspect of this second variant, in the particular formula (la) above, R 1 and R ₂ each represent an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C 6.

According to a second aspect of this second variant, in the particular formula (Ia) above, one of R 1 and R ₂ represents a hydrogen atom and the other of R 1 and R ₂ represents an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C 8.

In a second version, the compound according to the invention corresponds to the following particular formula (l-b):

H in which

- Ri and Ri represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, Ci to Cu hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group, optionally branched, in C3 to Cg,

- one of Rs and Rs represents a hydroxyl group —OH and the other of Rs and Re represents an aliphatic, saturated or unsaturated, linear or branched, C 1 to Cu, a cyclic, saturated or unsaturated hydrocarbon group, optionally branched, in C3 to C8, a hydroxyl group -OH or an alkoxyl group -OR, with R representing t

an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group or a cyclic, saturated or unsaturated, optionally branched, C3 to C8 aliphatic hydrocarbon group, and

- R7 and Re represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group, optionally branched, in C3 to Ce.

Preferably, in the particular formula (1-b) above, Rs and Re are such that:

- one of Rs and R6 represents a hydroxyl group -OH and the other of Rs and Re represents an alkyl group, linear or branched, C4 to Cio, advantageously C8, or an alkoxyl group -OR, with R representing an alkyl group, linear or branched, C2 to C8, advantageously C4, and

- R7 and Rg represent, independently of one another, an alkyl group, linear or branched, C4 to C10, advantageously Cg.

Thus, and as already indicated previously, the compound of particular formula (1-b) can correspond to a bifunctional compound which comprises:

- either a phosphinate group -P0 (0H) R6 or -PO (OH) Rs and an amide group -COR7R8, in the case where one of Rs and Re represents -OH and the other of Rs and R6 represents a group alkyl as specified above,

- Or a phosphonate group -PO (OH) (OR) and an amide group -COR7R8, in the case where one of Rs and Rs represents -OH and the other of Rs and Re represents an alkoxyl group -OR such that specified above.

Also preferably, in the particular formula (1-b) above, and according to a first variant, R 1 and R 2 each represent a hydrogen atom.

Also preferably, in the particular formula (ib) above, and according to a second variant, at least one of R 1 and R ₂ represents an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to This.

Thus, and according to a first aspect of this second variant, in the particular formula (ib) above, R 1 and R ₂ each represent an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C 8.

According to a second aspect of this second variant, in the particular formula (ib) above, one of R 1 and R ₂ represents a hydrogen atom and the other of R 1 and R ₂ represents an alkyl group, linear or branched, C 1 to C 10, advantageously C 1 to C 6.

According to the second aspect of this second variant, the compound of particular formula (ib), the use of which is the subject of the present invention may comprise an alpha branch of the ether, either on the side of the phosphonate group (in which case R ₂ = H), or on the side of the amlde group (in which case Ri = H).

IS According to this second aspect, the compound of particular formula (Ib) is advantageously that in which R ₂ represents a hydrogen atom.

Other characteristics and advantages of the invention will emerge better on reading the examples which follow and which relate to the synthesis of compounds in accordance with the invention as well as to tests which demonstrate the suitability of these compounds. in extracting all or part of the rare earths from aqueous solutions comprising phosphoric acid and in which said rare earths are present.

It is specified that these examples are given only by way of illustration of the objects of the invention and do not in any way constitute a limitation of these objects.

2S

EXAMPLES

SYNTHESIS OF COMPOUNDS IN ACCORDANCE WITH THE INVENTION

Example 1: Synthesis of a phosphine b / s-oxide

The synthesis implements an alcohol-phosphine oxide with a chloride-phosphine oxide, according to the Williamson reaction, in the presence of sodium hydride (NaH) in tetrahydrofuran (THF).

The corresponding reaction, noted (1), is as follows:

phosphine alcohol oxide phosphine chloride Rj, Rj alkyl groups Rj *. Rg * alkyl groups

NaH / THF

phosphine fe / s-oxide Compound (l-a)

More particularly, the synthesis referred to here is that of phosphine dioctyl b / s-oxide, which corresponds to the compound of formula (Ia) in which Ri = R2 = H and Rs = Re »Rs '= Re' = n-CgHn = n-octyl (hereinafter abbreviated as' Oct).

The dl-octyl phosphlne b / s-oxide is obtained by carrying out the following reaction (2):

OO o _ct -S ^ ^OH ₊ o «'^ ^cl _ϋ! Ϋ ™ £.

Ort Od

O o

11

Ws-dl-octyl phosphine oxide (2) 1- (hydroxymethyl) dl-octyl phosphine oxide 1- (chloromethyl) dl-octyl phosphine oxide

1.1 Synthesis of 1- (hydroxymethyl) -dl-octyl phosphine oxide

The synthesis of 1- (hydroxymethyl) -di-octyl phosphine oxide is carried out from phosphine di-octyl oxide, this phosphine di-octyl oxide itself being synthesized from a phosphite.

1.1.1 Synthesis of dl-octyl phosphine oxide

Di-octyl phosphine oxide is synthesized from diethyl phosphite, according to the following reaction (3):

EttX?

EtCT'H

Oct-MgBr

And _j0 dléthyie phosphite

4S’C, 4h

Yid "9S%

O ockJ

Oct ^x Ή phosphine di-octyl oxide

The operating protocol followed for the implementation of reaction (3) is as follows: to a suspension of magnesium n-octyl (noted Oct-MgBr) at 2 mol / L in ether (100 mL, i.e. approximately 3 eq ) is added dropwise, at 0 ° C. and with stirring, diethyl phosphite (1 eq, ie 13.5 g or 70 mmol). After total addition, the mixture is brought slowly to room temperature and then to 45 ° C. for 4 h. The mixture is then acidified with a 25% aqueous solution of sulfuric acid H2SO4 added dropwise at 0 ° C. Once the effervescence has stopped, an equal amount of water and ether is added to the mixture. The organic phase is then separated and washed successively with a solution of potassium carbonate K2CO3 at 10% (twice), with water (twice) and then with brine (twice). The organic phase is then dried over sodium sulphate Na2SO4, filtered and then concentrated to obtain phosphine di-octyl oxide (yield of 95%) which is in the form of a white powder.

The characterization data of this phosphine di-octyl oxide are as follows:

¹ H NMR (400MHz, CDCl3) δ (ppm): 7.38 (d, 1H, PH); 1.82-1.53 (m, 8H, CH2-CH2-P); 1.41-1.22 (m, 20H, CH2); 0.85 (m, 6H, CHj) ³¹ P NMR (160 MHz, CDCh) δ (ppm): 35.3

1.1.2 Synthesis of 1- (hydroxymethyl) -dl-octyl phosphine oxide

1- (Hydroxymethyl) -di-octyl phosphine oxide is synthesized from di-octyl phosphine oxide as obtained previously (see paragraph 1.1.1), according to the following reaction (4):

O OCUM

Oct ^x H phosphine di-octyl oxide

CHjfOHh

Na, EtOH 9O'C, 2h Yield "8O% (4)

The operating protocol followed for the implementation of reaction (4) is as follows: a solution of phosphine di-octyl oxide (1 eq) in ethanol

1-fhydroxymethylj-dl-octyl phosphine oxide (0.5 mol / L) are added, with stirring, sodium Na (previously activated in methanol) and then paraformaldehyde (1.2 eq). The mixture is then brought to reflux (80 ° C.) for 2 h. The solvent is then evaporated off. The mixture is then taken up in dichloromethane (DCM), then washed with water (twice) and with brine (twice). The organic phase is dried over Na2SO4, filtered and concentrated to obtain 1 (hydroxymethyl) -dl-octyl phosphine oxide (yield of 80%) which is in the form of a very viscous oil.

The characterization data of this 1- (hydroxymethyl) -dioctyl phosphine oxide are as follows:

NMR (400MHz, CDCl) 6 (ppm): 3.89 (s, 2H, CHi-OH); 1.80-1.72 (m, 4H, CH ₂ -P); 1.64-1.55 (m, 4H, CH ₂ -CH ₂ -P); 1.42-1.27 (m, 20H, CH ₂ ); 0.90 (m, 6H, CHj)

³ⁱ P NMR (160 MHz, CDCb) 6 (ppm): 49.1

1.2 Synthesis of 1- (Ch1oromethyl) -dl-octyl phosphine oxide

The synthesis of 1- (chloromethyl) -di-octyl phosphine oxide is carried out from 1- (hydroxymethyl) -di-octyl phosphine oxide as obtained previously (see paragraph 1.1.2), according to the following reaction (5):

O

1- (hydroxymethyl) -di-octyl phosphine oxide

PCIs toluene 90 * C2h Yield-7S%

(5) 1- (chloromethyl) * dl-octyl phosphine oxide

The operating protocol followed for the implementation of reaction (5) is as follows: to a solution formed of 1- (hydroxymethyl) -di-octyl phosphine oxide (1 eq) in anhydrous toluene (0.5 mol / L) is added, at 0 ° C and with stirring, phosphorus pentachloride PCls (2 eq) in small portions. After total addition, the mixture is slowly brought to room temperature then at reflux (110 ° C.) for 2 h. The excess of PCI5 is then neutralized by adding, dropwise, water at O'C. Fols the effervescence stopped, a quantity of water equal to half the volume of toluene is added and the mixture is stirred for 10 minutes. The organic phase is then separated and washed with a sodium hydroxide solution NaOH (0.5M) and with brine. It is then dried over Na2SO4, filtered and concentrated to obtain 1- (chloromethyl) -di-octyl phosphine oxide (yield 76%) which is in the form of a viscous oil.

The characterization data of this 1- (chloromethyl) -dioctyl phosphine oxide are as follows:

NMR (400 MHz, CDCh) δ (ppm): 3.58 (d, 2H, J = 8Hz, CH2-CI); 1.91-1.82 (m, 4H, CH2-P); 1.74-1.56 (m, 4H, CH2-CH2-P); 1.48-1.26 (m, 20H, CH2); 0.90 (m, 6H, CH ₃ ) ³¹ P NMR (160 MHz, CDCh) Ô (ppm): 49.3

1.3 Synthesis of dl-octyl phosphine b / s-oxide

The synthesis of di-octyl phosphine b / s-oxide is obtained by the reaction of 1- (hydroxymethyl) -di-octyl phosphine oxide and 1 (chloromethyl) -di-octyl phosphine oxide synthesized previously. (see respectively paragraphs 1.1 and 1.2 above), according to the following reaction (2 *):

O O O O H H Oct- ^ ° ^H Oct + - NaH / THF Oct-Ρχ ^ Ο— ^ Oct Oct Oct (2 *) Oct ¹ 12h Yd »82X 1- (hyd roxymethyl 1) dl-octyl phosphine oxide 1- (chloromethyl) di-octyl phosphine oxide dl-octyl phosphine b / s-oxide

The operating protocol followed for the implementation of this reaction (2 ¹ ) is ie as follows: to a suspension of sodium hydride NaH (4 eq, previously washed 2 times with pentane) in anhydrous THF (1 mol / L) a solution formed by 1- (hydroxymethyl) -di-octyl phosphine oxide in THF (1 eq at 0.5 mol / L) is added dropwise. After total addition, the mixture is stirred for 1 h and then a solution formed by 1- (chloromethyl) -di-octyl phosphine oxide (1.2 eq) in THF is added dropwise. The mixture is then stirred for 12 h. The crude is then acidified using a solution of hydrochloric acid HCl (3M), added dropwise at 0 ° C. The solvent is then evaporated off. The crude is taken up in ethyl acetate then washed with HCl (3M) (2 fols) and with water (2 times). The organic phase is dried over Na2SO4, filtered and then concentrated in a rotary evaporator. The crude product obtained is then purified by recrystallization from ethyl acetate to obtain the b / s-octyl phosphine oxide (with a yield of 82%) which is in the form of a white powder.

The characterization data of this phosphine di-octyl ws-oxide are as follows:

NMR (400 MHz, CDCh) δ (ppm): 3.90 (d, 4H, J = 6.4Hz, CHz-O); 1.78-1.57 (m, 16H,

CHi-CH1-P); 1.42-1.27 (m, 40H, CH ₂ ); 0.90 (m, 12H, CH ₃ )

³ⁱ P NMR (160 MHz, CDCh) δ (ppm): 46.1

Example 2: Synthesis of a phosphonate-phosphine oxide

The synthesis uses an alcohol-phosphonate with a phosphine chloride, according to the Williamson reaction, in the presence of sodium hydride (NaH) and potassium iodide (K1) in tetrahydrofuran (THF).

The corresponding reaction, noted (Ibis), is as follows, it being specified that one of the alkoxyl groups among Rs and Re hydrolyses during this reaction:

O

alcohol-phosphonate R $, R _e alkoxy groups

O

NâH / KI / THF

O O »1 H

phosphonate-phosphine oxide Compound (ha) (Ibb) phosphine chloride-oxide Rs ’> V alkyl groups

More particularly, the synthesis referred to here is that of (((dioctanoylphosphoryl) -2-oxoethoxy) methyl) -butyl phosphonate, which corresponds to the compound of formula (Ia) in which R 1 = R ₂ = H, one of Rs and R6 is -OH and the other of Rs and R6 is n-QHgO (hereinafter abbreviated BuO) and Rs' = Re ^{, =} n-octyl (hereinafter abbreviated Oct).

Butyl (((dioctanoylphosphoryl) -2-oxoethoxy) methyl) -phosphonate is obtained by carrying out the following reaction (6):

O II

Oct? ^

NaH / KI / THF

O

II

O II

Oct

BuO '^ ^Ox ^^ Oct

OH Oct 1- (chloramethyl) di-octyl phosphine {((dloctanoylphosphory 1) -2-0 xoethoxy) methylbutylphosphonate

(6)

2.1 Synthesis of l- (hydroxymethyl) -dl-butyl-phosphonate

The synthesis of 1- (hydroxymethyl) -di-butyl-phosphonate is carried out from a phosphite, in this case, dibutyl phosphite, according to the following reaction (7):

BuCk? BuCT Ή + HCHO

NEtj dibutyl phosphite

90X 2h

Yield "68% _nn O

BuOxiï BuO '

OH (7) l- (hy droxymethyl-dl-butyl-phosphates

The operating protocol followed for the implementation of reaction (7) is as follows: a mixture of dibutyl phosphite (1 eq) and formaldehyde (1.2 eq) in triethylamine NEt3 is brought to reflux (90 ° C. ) with stirring for 2 h. The triethylamine is then evaporated off. The crude is taken up in DCM then washed with saturated NaHCO3 solution (2 times) and with brine (2 times). The organic phase is dried over Na 2 SO 4 and then concentrated in a rotary evaporator. The excess formaldehyde is distilled in a ball oven under reduced pressure. The crude product obtained is then purified by flash chromatography on a silica gel column (eluent: cyclohexane / ethyl acetate from 100/50 to 50/100, v / v) to obtain 1- (hydroxymethyl) -di-butyl- phosphonate (68% yield) which is in the form of a viscous oil.

The characterization data of this l- (hydroxYmethyl) -di-butylephosphonate are as follows:

NMR (400 MHz, CDCh) δ (ppm): 4.84 (s, 1H, OH); 4.14-4.08 (m, 2H, O-CH2); 3.92 (d, 4H, J = 6Hz, CH1-OH); 1.71-1.64 (m, 4H, O-CH2-CH2); 1.47-1.37 (m, 4H, O-CH2-CH2-CH2); 0.95 (t, 6H, J = 7.4Hz, CH ₃ )

³¹ P NMR (160 MH2, CDCh) δ (ppm): 24.5

2.2 Synthesis of 1- (chloromethyl) -dl-octyl phosphine oxide

The synthesis of 1- (chloromethyl) -di-octyl phosphine oxide is carried out in accordance with reaction (5) and the operating protocol described in paragraph

1.2 cl above.

"

Synthesis of butyl (((dloctanoylphosphoryl} -2-oxoethoxy) methyl) -phosphonate

The synthesis of (((dioctanoylphosphoryl) -2-oxoethoxy) methyl) phosphonate is obtained by the reaction of 1- (hydroxymethyl) -di-butyl phosphonate and 1- (chloromethyl) -di-octyl phosphine oxide synthesized previously (see respectively paragraphs 2.1 and 1.2 above), according to the following reaction (6 '):

l- (hydroxymethyl) dl-butyl phosphonate

1-fchloromethyl) di-octyl phosphine oxide

NaH / KI / THF

12h

R ± -36%

O O η i>

OH Oct (((dloctanoylphosphoryl) -2-oxoethoxy) butyl methylj-phosphonate

The operating protocol followed for the implementation of this reaction (6 *) is as follows: to a suspension of sodium hydride NaH (4 eq, previously washed twice with pentane) in anhydrous THF (1 mol / L) , and in the presence of potassium iodide K1 (1 eq), a solution formed by l- (hydroxymethyl) -dlbutyl phosphonate in THF (1 eq at 0.5 mol / L) is added dropwise. After total addition, the mixture is stirred for 1 h and then a solution formed by 1 (chloromethyl) -di-octyl phosphine oxide (1.2 eq) in THF is added dropwise. The mixture is then stirred for 12 h. The crude is then acidified using a solution of hydrochloric acid HCl (3M), added dropwise at O’C. The solvent is then evaporated off. The crude is taken up in ethyl acetate and then washed with HCl (3M) (twice) and with water (twice). The organic phase is dried over Na25O4, filtered and then concentrated in a rotary evaporator. The crude obtained is then purified by recrystallization from ethyl acetate to obtain the (((dioctanoylphosphoryl) -2-oxoethoxy) methyl) -butyl phosphonate (with a yield of 36%) which is in the form of a white powder.

The characterization data of this (({dioctanoylphosphoryl) -2oxoethoxy) methyl) -butyl phosphonate are as follows:

* H NMR (400MHz, CDCh) δ (ppm) -. 9.68 (s, 1H, OH); 4.17-4.05 (m, 4H, CHi-0 and

O-CHrP-O); 3.95 (d, 2H, J = 7.6Hz, P-CH2-O); 1.86-1.78 (m, 4H, CH2-P); 1.71-1.55 (m, 6H,

CH2-CH2-P and O-CH2-CH2); 1.47-1.25 (m, 22H, CH2); 0.97-0.87 (m, 9H, CH ₃ )

³¹ P NMR (160 MHz, CDCh) δ (ppm): 51.9; 19.8

HRMS (EI +): calcd for C22H48O5P2: 454.3055; found: 454.3055

Example 3: Synthesis of a phosphlnate Ethyl octanoyl-phosphinate, or octyl ethoxyphophinate, is synthesized

from trlethyl phosphite, according to the following reaction (8). *

O

E ^t0 ^ ₊ EtOOEt

Oct-MgBr

EtjO trlethyl phosphite

0'C, lh Yield 72%

O oct'.y / '' • il EtO H (8) ethyl octanoyl-phosphinate

The operating protocol followed for the implementation of reaction (8) is as follows: to a suspension of magnesium n-octyl (noted Oct-MgBr) at 2 mol / L in ether (20 mL, i.e. approximately 1, 5 eq) is added dropwise, over a period of 1 h, at 0 ° C. and under an argon atmosphere, triethyl phosphite (10 mL or 57.5 mmol). After total addition, the mixture is stirred vigorously and then a 1 M HCl solution (50 mL) is added until the salts have completely dissolved (the addition of ether may optionally be necessary). The mixture is brought slowly to room temperature and then to 45 ° C for 4 h. The mixture is then extracted with 100 ml of ether (2 times). The organic phase is then separated and washed successively with 100 mL of 1M HCl, with 100 mL of water and then with 100 mL of brine. The organic phase is then dried over MgSO4, and the solvent is evaporated. After purification by flash chromatography on a silica gel column (eluent: cydohexane / ethyl acetate), ethyl octanoyl-phosphinate is isolated (yield of 72%) which is in the form of a colorless oil.

The characterization data of this ethyl octanoyl-phosphinate are as follows:

1 H NMR (400 MHz, CDCh) δ (ppm): 7.04 (d, 1H, PH); 4.22-4.05 (m, 2H, O-CH2); 1.81-1.73 (m, 2H, P-CHi); 1.65 to 1.54 (m, 2H, P-CHj-CHI): 1.42 to 1.24 (m, 13H, CH j and O-CH2-CH _3); 0.89 (t, 3H, J = 7 Hz, CH3)

³¹ P NMR (160 MHz, CDCh) δ (ppm): 39.0

Example 4: Synthesis of alcohol-phosphonates

An alcohol phosphonate can be obtained by reacting a phosphite with an aldehyde according to the following reaction (9):

0 m O + _O A NEt ₃ 0) R ₆ H Rf ^ H 90'C, 2h phosphite aldehyde Yield> 50X Ri alcohol phosphonate

Thus, as we have already seen in paragraph 2.1 above, 1 (hydroxymethyl) -di-butyl phosphonate was synthesized by the reaction of dibutyl phosphite (Rs = Rè = C4H9O) with formaldehyde (R 1 H ).

Other alcohol-phosphonates were synthesized according to the following operating protocol: a mixture of phosphite (1 eq) and aldehyde (1.2 eq) in trlethylamine is brought to reflux (90 ° C.) with stirring for 2 h . The trlethylamine is then evaporated. The crude is taken up in DCM then washed with a saturated NaHCO ₃ solution (twice) and with brine (twice). The organic phase is dried over Na ₂ SO4 and then concentrated in a rotary evaporator. The excess formaldehyde is distilled in a ball oven under reduced pressure. The crude product obtained is then purified by flash chromatography on a silica gel column (eluent: cydohexane / ethyl acetate from 100/50 to 50/100, v / v) to obtain the corresponding alcohol phosphonate (with a higher yield 50%) which is in the form of a viscous oil or a white powder, as the case may be.

4.1 Synthesis of 1- (hydroxynonyl) -di-butyl-phosphonate

1- (hydroxynonyl) -di-butyl-phosphonate is the alcohol-phosphonate in which Rs = R R = n-CiHgO (BuO) and Ri = n-CeHn (Oct). It thus responds to the following formula:

Oct

The characterization data of this compound, synthesized with a yield of 58%, are as follows:

1 H NMR (400 MHz, CDCh) 6 (ppm): 4.13-4.04 (m, 4H, O-CHi); 3.85-3.80 (m, 1H, CH); 1.82-1.59 (m, 6H, CH ₂ ); 1.42-1.24 (m, 16H, CH ₂ ); 0.93-0.84 (m, 9H, CHj)

^3t NMR P (160 MHz, CDCh) S (ppm): 25.4

4.2 Synthesis of l- (hydroxyethyl) -dl-butyl-phosphonate

1- (Hydroxyethyl) -di-butyl-phosphonate is the alcohol-phosphonate in which Rs “R6 = n-CjHgO (BuO) and Rl = CH1. It thus responds to the following formula:

The characterization data of this compound, synthesized with a yield of 54%, are as follows:

^J H NMR (400MHz, CDCh) δ (ppm): 4.87 (s, 1H, OH); 4.07-3.95 (m, 5H, CH and O-CH ₂ ); 1.62-1.54 (m, 4H, O-CH ₂ -CH ₂ ); 1.38-1.28 (m, 7H, O-CH ₂ -CH ₂ -CH2 and CHj); 0.86 (t, 6H, J = 7.4Hz, CHj)

³¹ P NMR (160 MHz, CDCh) δ (ppm): 25.8

4.3 Synthesis of l * (hydroxymethyl) -di-ethylhexyl-pho $ phonate

1- (hydroxymethyl) -di-ethylhexyl-phosphonate is the alcoholphosphonate in which Rs »R6 = 2-ethylhexyl (denoted EtHex) and Ri = H. It thus corresponds to the following formula:

AndHexoj?

EtHexO

The characterization data of this compound, synthesized with a yield of 78%, are as follows:

¹ H NMR (400 MHz, CDCh) δ (ppm): 4.04-3.98 (m, 4H, O-CH ₂ ); 3.92 (d, 2H, J = 6Hz,

CHz-OH); 1.60-1.54 (m, 2H, CH); 1.44-1.28 (m, 16H, CHi); 0.91 (t, 6H, J = 7.2 Hz, CH ₃ )

³¹ P NMR (160 MHz, CDCh) δ (ppm): 24.2

Example 5: Synthesis of an alcohol-phosphlnate

An alcohol-phosphinate can be obtained by reacting a phosphlnate with an aldehyde according to the following reaction (9 ‘):

0 Mr. O + A NEt ₃ % ΟΗ (9 ') Re H Rf ^ H 90'C, 2h Yid> 50% phosphlnate aldehyde alcohol-phosphinate

Thus, the synthesis of 1- (hydromethyl) -ethyl octanoyl-phosphinate is obtained by the reaction of ethyl octanoyl-phosphinate synthesized in accordance with Example 3 with formaldehyde.

1- (hydroxymethyl) -ethyl octanoyl-phosphinate is the alcoholphosphinate in which Rs - n-CsHn (Oct), R6 = C2H5O (EtO) and Ri = H. It thus corresponds to the following formula:

_. ⁰

OcKu> - ^, OH

EtO

The characterization data of this compound, synthesized with a yield of 38%, are as follows:

1 H NMR (400 MHz, CDCh) δ (ppm): 4.98 (s, 1H, OH); 4.14-4.08 (m, 2H, O-CH3); 3.88-3.84 (m, 2H, CHi-OH); 1.84-1.77 (m, 2H, P-CHj); 1.64-1.56 (m, 2H, P-CH1-CHj); 1.40-1.27 (m, 13H, CH ₂ and O-CH ₂ -CH ₃ ); 0.88 (t, 3H, J = 7.2Hz, CH ₃ )

³¹ P NMR (160 MHz, CDCb) δ (ppm): 25.8

Example 6 Synthesis of amido-phosphonates

The synthesis of an amldo-phosphonate uses an alcoholphosphonate with a halide-amlde, according to the Williamson reaction, in the presence of sodium hydride (NaH) and potassium iodide (K1) in tetrahydrofuran (THF) .

The corresponding reaction, denoted (10), is as follows, it being specified that one of the alkoxyl groups among Rs and Re hydrolyzes during this reaction:

O

Rf ^{0H 5} R ^R 6Ri

NaH / K1 / THF alcohol-phosphonate R $, Re “alkoxyl groups halide-amide R ?, Rg alkyl groups

OO ^R 5.6 Rj R ₂ a mldo-phosphonate Compound (lb) (10)

Several syntheses of amldo-phosphonates will now be described. These syntheses were all carried out according to the following operating protocol: to a suspension of NaH (4 eq, previously washed 2 fols with pentane) in anhydrous THF (1 mol / L) is added, with stirring, Kl (1 eq). The suspension is cooled to 0 ° C and a solution of alcohol phosphonate in THF (leq 0.5 mol / L) is added dropwise. After total addition, the mixture is stirred for 1 h at 0 ° C. and then a solution of amlde-halide (1.2 eq) in THF is added dropwise. The mixture is then stirred for 6 h. The crude is then acidified using a saturated solution of ammonium chloride (NH4Cl), added dropwise at 0 ° C. Once the effervescence has stopped, an amount of this solution equal to half the volume of THF is added and the mixture is stirred for 15 min. The solvent is then evaporated off. The crude is taken up in ethyl acetate and then washed with saturated NH4Cl (2 times) and with water (2 times). The organic phase is dried over NazSO4 and then concentrated in a rotary evaporator. The crude product obtained is then purified by flash chromatography on a silica gel column (eluent: ethyl acetate / methanol from 100/0 to 80/20, v / v) to obtain the corresponding amldo-phosphonate which is presented under the heading form of a viscous oil.

6.1 Synthesis of butyl (((N, N-dloctylcarbamoyl) -2-oxoethoxy) methyl) -phosphonate

The synthesis of (((N, N-dioctylcarbamoyl) -2-oxoethoxy) methyl) butyl phosphonate is obtained by the reaction of alcohol-phosphonate in which Rs = Re = n-C4HgO (BuO) and Ri - H ( see paragraph 2.1 above), with the amde-halide in which X = Cl, R7 = Rs = n-CsHn (Oct) and R2 = H.

The corresponding reaction, noted (11), is as follows:

OOOO * CI ^, C, _N , Oct "W" _BuO -P ^ o ^, c. _N zOct ₍₁₁ ) ^0Bu Oct ^Yd -72% OH

The characterization data of this amldo-phosphonate, synthesized with a yield of 72%, are as follows:

NMR (400 MHz, CDCh) δ (ppm): 10.9 (s, 1H, OH); 4.34 (s, 2H, CO-CH1-O); 4.14-4.08 (m, 2H, O-CH2); 3.95 (d, 2H, J = 8Hz, P-CH2-O); 3.30 (t, 2H, J - 7.8Hz, CH2-N); 3.13 (t, 2H, J = 7.8Hz, CH ₂ -N); 1.70-1.63 (m, 2H, O-CH1-CH1); 1.58-1.50 (m, 4H, CH2-CH2-N); 1.44-1.37 (m, 2H, O-CH2-CH2-CH2); 1.32-1.22 (m, 20H, CH ₂ ); 0.94-0.86 (m, 9H, CH ₃ )

^3t P NMR (160 MHz, CDCl3) Ô (ppm): 21.5

HRMS (EI +): calcd for C23H48NO5P: 449.3348; found: 449.3348

6.2 Synthesis of (((N, N-dlethylhexylcarbamoyl) -2-oxoethoxy) methyl) butyl phosphonate

The synthesis of (((N, N-diethylhexylcarbamoyl) -2-oxoethoxy) methyl) butyl phosphonate is obtained by the reaction of the alcohol-phosphonate in which Rs = Re = n-QHsO (BuO) and Ri = H ( see paragraph 2.1 above), with the halide-amlde in which X = Cl, R7 = Ra = 2-ethylhexyl (denoted EtHex or HexEt) and R2 = H.

The corresponding reaction, noted (12), is as follows:

O

CI> _{sX .C} ^ _N , HexEt NaH / KI / THF I HexEt

6h

Yid-42%

O O

ΒυΟ ^ θ ^ 'Ζ ^ (12) ^0H HexEt

The characterization data of this amido-phosphonate, synthesized with a yield of 42%, are as follows:

^J H NMR (400 MHz, CDCh) δ (ppm): 7.96 (s, 1H, OH); 4.37 (s, 2H, CO-CH2-O); 4.17-4.07 (m, 2H, O-CHi); 3.92 (d, 2H, J = 8Hz, P-CHt-O); 3.40-3.20 (m, 2H, CH _r N); 3.06-3.0 (m, 2H, CH ₂ -N); 1.72-1.56 (m, 4H, O-CH2-CH2 and CH); 1.47-1.37 (m, 2H, O-CH2-CH2-CH2); 1.36-1.18 (m, 16H, CH2); 0.96-0.86 (m, 15H, CHj)

³ⁱ P NMR (160 MHz, CDCh) δ (ppm): 20.6

HRMS (EI +): calcd for C23H48NO5P: 449.3348; found: 449.3348

6.3 Synthesis of (((N, N-diethylhexylcarbamoyl) -2-oxoethoxy) nonyl) butyl phosphonate

The synthesis of (((N, N-diethylhexylcarbamoyl) -2-oxoethoxy) nonyl) butyl phosphonate is obtained by the reaction of alcohol-phosphonate in which Rs = Rs = n-CiHgO (BuO) and Ri = n- CsHi7 (Oct) (see paragraph 4.1 above), with the halide-amide in which X = Cl, R7 = Ra = n-CgHn (Oct) and R2 = H.

The corresponding reaction, denoted (13), is as follows:

O

O

Clx ^ Cx ^^ Oct I

NaH / KI / THF

Oct

6h

Yd "22X

O O

BuO ' _/ ^P ^ r ° ^ ^C ' _N ^x ° ^Ct (13) ^{H0 Oct} Oct

The characterization data of this amido-phosphonate, synthesized with a yield of 22%, are as follows:

1 H NMR (400 MHz, CDCh) δ (ppm): 9.85 (s, 1H, OH); 4.61 (d, 1H, J = 15.4Hz, CO-CH ₂ -O); 4.19 (d, 1H, J = 15.4Hz, CO-CH2-O); 4.16-4.07 (m, 2H, O-CH2); 3.62-3.58 (m, 1H, P-CH-O); 3.31 (t, 2H, J = 7.8Hz, CH2-N); 3.11 (t, 2H, J = 7.8Hz, CH ₂ -N); 1.96-1.74 (m, 2H, CH2-CH-P); 1.70-1.60 (m, 2H, O-CH2-CH2); 1.59-1.47 (m, 4H, CH2-CH2-N); 1.45-1.35 (m, 2H, O-CH2-CH2-CH2); 1.34-1.20 (m, 32H, CH2); 0.94-0.86 (m, 12H, CHa)

³¹ P NMR (160 MHz, CDCh) δ (ppm): 22.1

HRMS (EI +): calcd for C31HmNOsP: 562.4600; found: 562.4604 '

6.4 Synthesis of (((N, N-dlethylhexylcarbamoyl) -2-oxoethoxy) ethyl) butyl phosphonate

The synthesis of (((N, N-diethylhexylcarbamoyl) -2-oxoethoxy) ethyl) butyl phosphonate is obtained by the reaction of alcohol-phosphonate in which Rs = FU = n-CiHgO (BuO) and Ri = CHj ( see paragraph 4.2 above), with the halureamlde in which X = Cl, R7 = Rg = n-CgHn (Oct) and R ₂ = H.

The corresponding reaction, denoted (14), is as follows:

O

Cl

NaH / KI / THF

I Oct

6h

Yid-10%

□ U ./*

I Oct (14)

The characterization data of this amido-phosphonate, synthesized with a yield of 10%, are as follows:

^3H NMR (400MHz, CDCl) 6 (ppm): 4.48 (d, 1H, J = 16Hz, CO-CH ₂ -O); 4.19 (d, 1H, J = 15.4Hz, CO-CHi-O); 4.21-4.10 (m, 3H, CO-CH ₂ -O and O-CH ₂ ); 3.77-3.71 (m, 1H, P-CH-O); 3.33 (t, 2H, J - 7.6Hz, CHg-N); 3.10 (t, 2H, J = 7.6Hz, CH _r N); 1.73-1.65 (m, 2H, O-CH1-CH1); 1.60-1.38 (m, 9H, CH ₂ -CH ₂ -N and O-CH ₂ -CH ₂ -CH1 and CH _r CH); 1.37-1.21 (m, 20H, CHi); 0.97-0.87 (m, 9H, CH ₃ )

³¹ P NMR (160 MHz, CDCb) 6 (ppm): 22.3

HRMS (EI +): calcd for C24H50NO5P: 463.3505; found: 463.3507

6.5 Synthesis of (((N, N-dlethylhexylcarbamoyl) -l-oxopropan-2-yl) methyl) butyl phosphonate

The synthesis of (((N, N-diethylhexylcarbamoyl) -l-oxopropan-2yi) methyl) -phosphonate is obtained by the reaction of alcohol-phosphonate

Ί in which Rs ® Re = n-GHgO (BuO) and Ri = H (see paragraph 2.1 above), with the amide-halide in which X = Br, R? = Rs = n-CsHn (Oct) and R ₂ = CH1.

The corresponding reaction, noted (15), is as follows:

OO 0 0 _BU 0 -? '- ^OH * ^Br Y ^C ' N '° ^{, H / KI / rHF} >BuO'M'An' ⁰ (15) ^0Bu Oct “λ“ κκ OH ^ _ct

The characterization data of this amido-phosphonate, synthesized with a yield of 56%, are as follows:

1 H NMR (400 MHz, CDCh) 6 (ppm): 10.6 (s, 1H, OH); 4.47-4.42 (m, 1H, CH); 4.14-4.08 (m, 2H, O-CH ₂ ); 3.76 (dd, 2H, J = 8.8 & 3.8Hz, P-CH ₂ -O); 3.49-3.41 (m, 1H, CH ₂ -N); 3.30-3.16 (m, 3H, CH ₂ -N); 1.71-1.64 (m, 2H, O-CH ₂ -CH1); 1.61-1.48 (m, 4H, CH ₂ -CHrN); 1.47-1.37 (m, 5H, O-CHz-CHrCHj and CHj-CH); 1.34-1.24 (m, 20H, CH ₂ ); 0.96-0.86 (m, 9H, CH ₃ ) ³ⁱ NMR P (160 MHz, CDCh) S (ppm): 21.8

HRMS (EH ·): calculated for CmHsoNOsP: 463.3505; found: 463.3507

6.6 Synthesis of (((N, N-dioctylcarbamoyl) -2-oxoethoxy) methYl) -ethylhexyl phosphonate

The synthesis of (((N, N-dioctylcarbamoyl) -2-oxoethoxy) methyl) ethylhexyl phosphonate is obtained by the reaction of alcohol-phosphonate in which Rs = Re = 2-ethylhexyl (denoted EtHex or HexEt) and Ri = H (see paragraph 4.3 above), with the amide halide in which X - Cl, R7 = Re = n-CsHu (Oct) and R ₂ = H.

The corresponding reaction, denoted (16), is as follows:

O

EtHexO ^ Ç— ° ^H OHexEt

O O

NaH / KI / THF nr Ort HK) —--- EtHexO '^ °' ^ ^c 'N'' ¹

Yd-40% At I ⁰⁰ Oct

The characterization data of this amido-phosphonate, synthesized with a yield of 40%, are as follows:

NMR (400 MHz, CDCh) δ (ppm): 10.4 (s, 1H, OH); 4.35 (s, 2H, CO-CH1-O); 4.08-3.98 (m, 2H, O-CH2); 3.96 (d, 2H, J = 8Hz, P-CHz-O); 3.32 (t, 2H, J = 7.6Hz, CH1-N); 3.12 (t, 2H, J = 7.6Hz, CH2-N); 1.63-1.49 (m, 5H, CH ₂ -CH ₂ -N and CH); 1.48-1.23 (m, 28H, CH2); 0.92-0.88 (m, 12H, CHj)

³¹ P NMR (160 MHz, CDCh) δ (ppm): 21.2

HRMS (61+): calculated for C ₂ 7Hs6NO4P: 489.4025; found: 489.4024

Example 7: Synthesis of an amido-phosphinate

The synthesis of an amido-phosphinate uses an alcoholphosphinate with a halide-amide, according to the reaction of Williamson, in the presence of sodium hydride (NaH) and potassium iodide (K1) in tetrahydrofuran (THF) .

The corresponding reaction, denoted (10bis), is as follows, it being specified that the alkoxyl group among Rs and Re hydrolyzes during this reaction:

O It aleool-phosphlnate

R $, R * “alkoxyl group * akyie stern

O

V '-'

RI ^R 2 R _s hatogenide-amide

R »“ groupsakyle

NaK / KI / THF

amido-phosphinate Compound p-b) (lObis)

The present reaction is illustrated with the synthesis of (((N, Ndioctylcarbamoyl) -2-oxoethoxy) methyl) -phosphinate of octyl which is obtained by the reaction of alcohol-phosphinate in which Rs (or R6) = n- C8Hi7 (Oct), Re (or Rs) = C ₂ HsO (EtO) and Ri = H (see example 5 above), with the halide-amide in which X = CI, R7 = Rg = n-CgHn ( Oct) and R ₂ = H.

It is specified that this synthesis is carried out according to the operating protocol described above, in chapter 6, for the synthesis of amido-phosphonates, the solution of alcohol-phosphonate in THF being, in the present case, replaced by a solution alcohol-phosphlnate.

The corresponding reaction, noted (17), is as follows:

X

Ο

II. Cl -___ Cx .., 0ct NaH / KI / THF + N —---- i 6h

Oct Yield-48%

Oct

O O

He II

OH (17)

Oct

The characterization data of this amido-phosphonate, synthesized with a yield of 48%, are as follows:

1 H NMR (400MHz, CDCh) δ (ppm) '. 4.34 (s, 2H, CO-Oh-O); 3.88 (d, 2H, J = 6Hz, P-CHi-O); 3.32 (t, 2H, J = 7.8Hz, CH ₂ -N); 3.12 (t, 2H, J 7, Hz, CHz-N); 1.88-1.80 (m, 2H, CHz-P); 1.72-1.62 (m, 2H, CH ₂ -CH ₂ -P); 1.61-1.49 (m, 4H, CH ₂ -CH ₂ -N); 1.44-1.20 (m, 28H, CH ₂ ); 0.93-0.88 (m, 9H, CH ₃ )

³¹ P NMR (160 MHz, CDCh) δ (ppm): 48.6

HRMS (EH): calcd for C4 HseNOiP: 489.4025; found: 489.4024

EXTRACTING PROPERTIES OF COMPOUNDS COMPLIANT WITH THE INVENTION METHODS OF EVALUATING THE EXTRACTING PROPERTIES

The extracting properties of the compounds were evaluated by measuring the distribution coefficients of the species in solution, by inductively coupled plasma optical emission spectrometry (in English, Inductively Coupled Plasma - Optic Emission Spectrometry or ICP-OES), after dilution. aqueous solutions at measurable contents (between 0 and 20 ppm), before and after contact, with the organic phase.

* Unless stated otherwise or the appearance of a third phase on extraction, the distribution coefficient of a metallic element M, denoted Dm, between an organic phase and an aqueous phase is determined by the following equation:

n M ™ ^M 'Ma ,.

with [MJorç. = concentration of the metallic element in the organic phase at extraction equilibrium (in mg / L), and [M] “j. = concentration of the metallic element in the aqueous phase at extraction equilibrium (in mg / L).

* The selectivity of the extraction is systematically evaluated from the selectivity factor, noted FS and determined by the following equation:

with Dmi = distribution coefficient of the metallic element Ml, and

Dm2 = distribution coefficient of the metallic element M2 (mainly iron will be considered).

* The performance of the extraction is expressed by the percentage of extraction, noted E (%) and determined by the following equation:

E (%> ^Dm . _A , X100 ^D " ⁺ (0) with Dm = distribution coefficient of the metallic element M, and

A / O = ratio between the volumes of the aqueous and organic phases.

OPERATING PROTOCOLS

In order to be as close as possible to the conditions encountered during the leaching juice extracts, the extraction tests were carried out with acidic aqueous phases comprising several metallic elements, denoted M, and organic phases comprising an extradant. More precisely, these metallic elements M comprise a transition metal (Fe) as well as lanthanides, denoted Ln, 5 in number (La, Nd, Gd, Dy and Yb).

The compositions of the aqueous and organic phases, before contact, are as follows, it being specified that the unit M used here and below corresponds to the abbreviation of the unit of the International System mol / L:

Aqueous phases:

. 1 mM of each of the lanthanides La, Nd, Gd, Dy and Yb, and 50 mM of Fe,. from 0.5 M to 5 M in H3PO4 with, optionally, a modification of the ionic strength by addition of 0.1 M to 2 M of NaNO3.

Organic phases:

. from 10 mM to 100 mM extraditing in dodecane, it being noted that the molar concentration in extraditing is at least equal to twice the total molar concentration of lanthanides.

Each aqueous solution is placed in contad with an organic solution comprising the extradant considered in dodecane.

This contading is carried out volume by volume (that is to say that the volumes of organic solution Vorg and aqueous solution Vaq are identical, Vorg = Vaq), by mechanical stirring, for 20 minutes, in a 15 mL tube. and at room temperature (21-22 ° C). After centrifugation, the aqueous and organic phases obtained are separated from one another and are then each analyzed by ICP-OES.

EXPERIMENTAL RESULTS

Example 8: Extradion by TODGA (comparative example)

This example was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in varying concentrations of phosphoric acid ([H3PO4] = from 0.5 M to 5 M)

Organic phase: 10 mM extraditing agent in dodecane, extraditing agent being the TODGA of formula (extraditing agent described in reference [1]):

OO

Oct ^ zC ^ O ^ Cx / Od NN

1I

OdOd

TODGA

The calculated values of the distribution coefficients D and the extradion percentages E (%) are reported in Table 1 below:

[H3PO4] (in M) 5 3 1 0.5 Element M D E {%) D E (%) D E (%) D E (%) Fe <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 The <0.001 <0.1 <0.01 <1 <0.01 <1 <0.01 <1 Nd <0.001 <0.1 <0.01 <1 <0.01 <1 <0.01 <1 Gd 0.01 1 0.01 1 <0.02 <2 <0.02 <2 Dy 0.01 1 0.01 1 <0.02 <2 <0.02 <2 Yb 0.01 1 0.01 1 <0.02 <2 <0.02 <2

Table 1

As reported in Table 1 above, the values of the extraction percentages E (%) as obtained are all less than 2%, regardless of the concentration of phosphoric acid in the aqueous phase.

These results clearly demonstrate the fact that TOGDA absolutely does not make it possible to extract the lanthanides from an aqueous phase comprising phosphorlque acid, unlike what occurs when the aqueous phase comprises nitric acid (see reference [1]).

Example 9; Extraction with a phosphonate-phosphine oxide

This example was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanum (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in varying concentrations of phosphoric acid ([H3PO4] = from 0.5 M to 5 M)

Organic phase: 10 mM of extractant in dodecane, the extractant being the following compound (see paragraph 2.3 above):

O

II BuO'Ç ^

OH

II

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 2.1 below:

[H3PO4] (inM) 5 3 1 0.5 Element M D E (%) D E (%) D E (%) D E (%) Fe 0.004 0.4 0.21 17 0.47 32 0.65 24 The <0.001 <0.1 0.03 3 0.03 3 0.06 6 Nd <0.001 <0.1 0.02 2 0.05 4 0.2 15 Gd <0.001 <0.1 0.02 2 0.05 5 0.15 13 Dy 0.15 13 0.06 6 0.12 11 0.29 22 Yb 0.63 39 2.56 72 6.8 87 10.4 91

Table 2.1

The calculated values of the selectivity factors FS for each lanthanum

Ln with respect to Fe, denoted FS ^ / pe, are reported in Table 2.2 below:

[H3PD4] (in M) 5 3 1 0.5 Lanthanlde Ln FSLn / Fe FSm / Fe FSui / Fe FSui / Fe The <0.25 0.14 0.06 0.09 Nd <0.25 0.10 0.11 0.26 Gd <0.25 0.10 0.11 0.23 Dy 2.5 0.29 0.26 0.45

Yb 158 12 14 16

Table 2.2

The calculated values of the selectivity factors FS for element Yb with respect to each element M, denoted FSyb / M, are reported in table 2.3 below:

[HjPCUl (in M) 5 3 1 0.5 Element M FSyb / M FSyb / M FSyb / M FSyb / M Fe 158 12 14 16 The > 200 85 > 200 173 Nd > 200 128 136 52 Gd > 200 128 136 69 Dy 63 43 57 36

Table 2.3

The extradant used in the present example is effective for the extradion of Yb in a phosphoric medium, very particularly at 0.5 M.

If the performance of the extradion of Yb is less than 5 M in [H3PO4] (39%), this extradion is, on the other hand, particularly selective with respect to the other lanthanldes (FSyb / Dy> 60 and FSyb / Ln > 200 for Ln = La, Nd, Gd) as well as with respect to iron (FSvb / Fe = 158) at such a molar concentration.

The performance of the extradion of Yb is increased for lower acidities (for example, E (%) = 91% at 0.5 M in [H3PO4]), but then a decrease in the selectivity fader is observed. -vis iron (FSyb / Fe = 16 at 0.5 M in [H3PO4D15 Example 10: Extradion by an amldo-phosphlnate

This example was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in varying concentrations of phosphoric acid ([H3PO4] = de

0.5M to 5M)

Organic phase: 10 mM of extractant in dodecane, the extractant being the following compound (see example 7 above):

„✓Oct N I Oct

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 3.1 below:

[H3PO4] (in M) 5 3 1 0.5 Element M D E (%) D E (%) D E (%) D E (%) Fe 0.001 0.1 0.24 19 0.54 35 0.51 34 The 0.01 1 0.02 2 0.02 2 0.07 7 Nd 0.03 3 0.02 2 0.03 3 0.17 15 Gd 0.04 4 0.03 3 0.02 2 0.25 20 Dy 0.07 7 0.04 4 0.02 2 0.25 20 Yb 0.11 10 0.20 17 0.23 19 1.52 60

Table 3.1

The calculated values of the F5 selectivity factors for each lanthanide

Ln with respect to Fe, denoted FSui / Fe, are reported in table 3.2 below:

[H3PO4] (in M) 5 3 1 0.5 Lanthanide Ln FSm / Fe FSm / Fe FSui / Fe FSüi / Fe The 10 0.08 0.04 0.14 Nd 30 0.08 0.06 0.33

Gd 40 0.13 0.04 0.49 Dy 70 0.17 0.04 0.49 Yb 110 0.83 0.43 2.98

Table 3.2

The extractant used in the present example is effective for the extraction of Yb in a 0.5 M phosphoric medium, with E (%) = 60%, it being noted that at this molar concentration of [H3PO4] , the selectivity towards iron is lower (FSywf * = 2.98).

Example 11: Extraction by a first amldo-phosphonate In this example 11, the extractant used is the following compound (see

paragraph 6.1 above):

OO ^0H Oct

11.1 A first series of extractions was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in varying concentrations of phosphoric add ([H3PO4] = from 0.5 M to 5 M)

Organic phase: 10 mM of the extractant above in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 4.1 below:

[H3PO4] (in M) 5 3 1 0.5 Element M D E (%) D E (%) D E (%) D E (%) Fe 0.02 1.5 0.04 4 0.18 15 0.21 17 The <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Nd 0.9 47 0.5 33 0.28 22 0.35 26 Gd 6.5 87 2.89 74 0.67 40 0.68 40 Dy 28.5 97 11.7 92 1.35 57 1.17 54 Yb 81 99 69.5 99 5.97 86 3.64 78

Table 4.1

The calculated values of the selectivity factors FS of each lanthanide

Ln with respect to Fe, denoted FSm / Fe, are reported in Table 4.2 below:

[H3PO4] (in M) 5 3 1 0.5 Lanthanide Ln FSln / fe FSbi / Fe FSln / Fe FSln / Fe The <0.1 <0.1 <0.1 <0.1 Nd 60 13 2 2 Gd > 200 74 4 3 Dy "200 > 200 8 6 Yb "200 "200 34 14

Table 4.2

11.2 A second series of extractions was carried out under the following conditions:

Aqueous phase : 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in 5 phosphoric acid ([H3PO4] = 5 M) Organic phase: varying concentrations of extractant ([extradant] = from 10 mM to 40 mM) in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 4.3 below:

[extraditing] (mM) 10 15 20 25 30 35 40 Element M D E (%) D E (%) D E (%) D E (%) D E (%) D E (%) D E (%) Fe 0.02 1.5 0.001 0.1 0.04 4 0.06 6 0.07 7 0.12 11 0.41 29 The <0.001 <0.1 0.2 17 0.34 25 0.49 33 0.69 41 1.1 52 5.2 84 Nd 0.9 47 2 67 2.9 74 3.7 79 4.5 82 6.2 86 24 96 Gd 6.5 87 15 94 19 95 22 96 23 96 26 96 51.5 98 Dy 28.5 97 48 98 59 98 67 99 70 99 75 99 94 99 Yb 81 99 > 500 299.9 > 500 299.9 > 500 299.9 > 500 "9.9 > 500 299.9 > 500 299.9

Table 4.3

11.3 A third series of extractions was carried out under the following conditions:

Aqueous phase : 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in 15 phosphoric acid ([H3PO4] = 5 M), optionally added with sodium nitrate ([NaNO ₃ ] = from 0 to 2 M) Organic phase: 15mM of the above extradant in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 4.4 below:

[NaNOaj (M) 0 0.1 0.5 1 2 Element M D E (%) D E (%) D E (%) D E (%) D E (%) Fe 0.001 0.1 0.01 0.1 0.04 4 0.06 6 0.07 7 The 0.2 17 0.19 16 0.41 29 0.51 34 0.57 36 Nd 2 67 3 73 6 86 7 88 7 87 Gd 15 94 25 96 72 99 105 99 111 99 Dy 48 98 97 98 331 99.7 535 99.8 > 500 £ 99.9 Yb > 500 299.9 > 500 299.9 > 500 299.9 > 500 299.9 > 500 299.9

Table 4.4

The extradant implemented in the present example is efficient for the extradion of all the lanthanides tested (with the exception of La), with a more marked performance for the lanthanides of the highest atomic numbers (Dy and Yb).

This extradant also makes it possible to achieve good selectivity with respect to iron (FSw / Fe - 60 and FSui / Fe greater (>), or even much greater ("), than 200 for Ln = Gd, Dy, Yb), in phosphoric medium at 5 M and 3 M.

The increase in the molar concentration by this extradant as well as the addition of NaNOa, make it possible to increase the performance of the extradion of all the lanthanides, in particular of the lanthanides of lower atomic number (La and Nd) and this , while maintaining good faders of separation vis-à-vis the iron.

Example 12: Extraction by a second amido-phosphonate In this example 12, the extractant used is the following compound (see

paragraph 6.6 above):

EtHexO ^^ - '° OH

II

XZ'C * » _z Oct N

I Oct

12.1 A first series of extractions was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in varying concentrations of phosphoric acid ([HaPO ^ from 0.5 M to 5 M)

Organic phase: 10 mM of the extractant above in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 5.1 below:

[H ₃ PO "] (in M) 5 3 1 0.5 Element M D E (%) D E (%) D E (%) D E (%) Fe 0.03 3 0.01 1 0.26 20 0.36 26.5 The <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Nd 0.07 6.5 0.1 9 0.03 3 0.01 1 Gd 0.08 7 0.1 9 0.04 4 0.01 1 Dy 0.14 12 0.2 17 0.11 10 0.07 6.5 Yb 0.26 21 0.72 42 1.40 58 1.67 62.5

Table 5.1

The calculated values of the selectivity factors F5 for each lanthanum

Ln compared to Fe, denoted F5ui / Fe, are reported in Table 5.2 cl below:

[H3PO4] (in M) 5 3 1 0.5 Lanthanlde Ln F5Ln / Fe F5ui / Fe F5m / Fe F5ui / Fe The <0.1 <0.1 <0.1 <0.1 Nd 2 2 8 0.1 Gd 3 8 0.1 <0.1 Dy 5 17 0.4 0.2 Yb 9 61 5.5 5

Table 5.2

12.2 A second series of extractions was carried out under the following conditions:

Aqueous phase : 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in phosphoric acid ([H3PO4] = 5 M) Organic phase: varying concentrations of extractant ([extraditing] = from 10 mM to 40 mM) in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 5.3 cl below:

(extractant] (mM) 10 15 20 25 30 35 40 element M D E (%) D E (%) D E (%) D E (%) D E (%) D E (%) D E (%) Fe 0.03 3 0.03 3 0.07 6.5 0.005 0.5 0.17 14.5 0.22 18 0.25 20 The <0.001 <0.1 0.11 10 0.17 14.5 0.23 19 0.32 24 0.37 27 0.44 31 Nd 0.07 6.5 0.28 22 0.41 29 0.56 36 0.78 44 0.94 48.5 1.1 53 Gd 0.08 7 0.32 24 0.45 31 0.61 38 0.85 46 1 51 1.3 56 Dy 0.14 12 0.47 32 0.68 40.5 0.95 49 1.3 56.5 1.6 61 2 66 Yb 0.26 21 2.5 71 3.2 76 4 80 5 83 6 85 7 87

Table 5.3

12.3 A third series of extractions was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in phosphoric acid ([H3PO4] = 5 M), optionally added with sodium nitrate ([NaNOj] = of 0 to 2 M)

Organic phase: 15 mM of the extractant above in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 5.4 cl below:

[NaNOa] (M) 0 0.1 0.5 1 2 Element M D E (%) D E (%) D E (%) D E (%) D E (%) Fe 0.03 3 0.004 0.4 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 The 0.11 10 0.07 7 0.11 10 0.16 14 0.17 15 Nd 0.28 22 0.18 15 0.4 29 0.55 35 0.67 40 Gd 0.32 24 0.23 19 0.6 38 1 50 1.5 61 Dy 0.47 32 0.35 26 0.82 45 1.3 57 2 66 Yb 2.5 71 0.6 36 0.9 47 1.1 53 1.5 59

Table 5.4

The extractant used in the present example remains effective for the extraction of Yb in a phosphoric medium, this extraction performance being inversely proportional to the molar concentration of [H3PO4].

As in Example 11, it is observed that the increase in the molar concentration by this extraditing as well as the addition of NaNCh, make it possible to increase the performance of the extraction of all the lanthanides, in particular the lanthanides of more low atomic number (La and Nd) while retaining good separation factors with respect to iron.

Example 13 Extraction by third an amldo-ohosphonate

In this example 13, the extractant used is the following compound (see paragraph 6.3 above):

We

II

Oct

13.1 A first series of extractions was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in varying concentrations of phosphoric add ([H3PO4] = from 0.5 M to 5 M)

Organic phase: 10 mM of the extractant above in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 6.1 below:

[H ₃ PO4] (in M) 5 3 1 0.5 Element M D E (%) D E (%) D E (%) D E (%) Fe 0.03 3 <0.001 <0.1 0.13 20 0.26 26.5 The <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Nd <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Gd <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Dy 0.02 2 0.02 2 0.07 6.5 0.09 8 Yb 0.16 14 0.5 33 2 66 2.4 71

Table 6.1

The calculated values of the selectivity factors FS for each lanthanum

Ln with respect to Fe, denoted FS ^ / f *, are reported in Table 6.2 below:

[H3PO4] (in M) 5 3 1 0.5 Lanthanide Ln FSLn / Fe FSLn / Fe FS ^ / Fe FSLn / Fe The <0.1 10 <0.1 <0.1 Nd <0.1 10 <0.1 <0.1 Gd <0.1 10 <0.1 <0.1 Dy 0.7 200 0.5 0.3 Yb 5.5 "200 15 9.5

Table 6.2

The calculated values of the selectivity factors FS of element Yb with respect to each element M, denoted FSyb / M, are reported in table 6.3 below:

[Η ₃ ΡΟ4] (in M) 5 3 1 0.5 Element M FSyb / M FSyb / M FSyb / M FSyb / M Fe 5.5 "200 IS 9.5 The > 150 "200 "200 "200 Nd > 150 "200 "200 "200 Gd > 150 "200 "200 "200

□ y 8 25 28 27

Table 6.3

13.2 A second series of extractions was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in phosphoric acid ([H3PO4] = 5 M)

Organic phase: varying concentrations of extractant ([extradant] = from 10 mM to mM) in dodecane

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 6.4 below:

[extractant] (mM) 10 15 20 25 30 35 40 Element M D E (%) D E (%) D E (%) D E (%) D E (%) D E (%) D E (%) Fe 0.03 3 0.002 0.2 0.02 2 0.04 4 0.08 7 0.12 11 0.18 15 The <0.001 <0.1 0.01 1 0.02 2 0.03 3 0.04 4 0.05 5 0.06 6 Nd <0.001 <0.1 0.06 6 0.07 6.5 0.1 9 0.12 11 0.14 12 0.16 14 Gd <0.001 <0.1 0.08 7 0.08 7 0.11 10 0.12 11 0.14 12 0.16 14 Dy 0.02 2 0.11 10 0.13 11.5 0.19 16 0.23 19 0.27 21 0.32 24 Yb 0.16 14 2.3 69 3 75 4 79 5 83 6 86 7 88

Table 6.4

Example 14: Extraction by a fourth amldo-phosphonate This example was carried out under the following conditions: Aqueous phase : 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in 15 varying concentrations of phosphoric acid ([H3PO4] = of 0.5M to 5M)

Organic phase: 10 mM of extractant in dodecane, the extractant being the following compound (see paragraph 6.4 above):

O o

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 7.1 below:

[H ₃ PO ₄ ] (in M) 5 3 1 0.5 Element M D E (%) D E (%) D E (%) D E (%) Fe 0.04 3.5 0.03 2.5 0.28 22 0.40 28 The <0.001 0, l < <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Nd <0.001 0, l < <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Gd <0.001 0, l < <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Dy 0.06 6 0.09 8 0.11 10 0.1 9 Yb 0.26 21 1 49 5.4 84 2.4 87

Table 7.1

The calculated values of the selectivity factors FS of each lanthanide

Ln compared to Fe, denoted FSm / Fe, are reported in table 7.2 below:

[H ₃ PO ₄ ] (in M) 5 3 1 0.5 Lanthanide Ln FSln / Fe FSln / Fe FSm / Fe FSm / Fe The <0.1 <0.1 <0.1 <0.1 Nd <0.1 <0.1 <0.1 <0.1 Gd <0.1 <0.1 <0.1 <0.1

Dy 1.7 3.5 0.4 0.3 Yb 7 37 19 17.5

Table 7.2

The calculated values of the selectivity factors FS of element Yb with respect to each element M, denoted FSyb / M, are reported in table 7.3 below:

[H3PO4] (in M) 5 3 1 0.5 Element M FSyb / M FSib / M FSyb / M FSyb / M Fe 7 37 19 17.5 The > 200 "200 "200 "200 Nd > 200 "200 "200 "200 Gd > 200 "200 "200 "200 Dy 4 11 49 69

Table 7.3

Example 15; Extraction by a fifth amldo-phosphonate

This example was carried out under the following conditions:

Aqueous phase: 1 mM of each lanthanide (La, Nd, Gd, Dy, Yb) + 50 mM of Fe in varying concentrations of phosphoric acid ([H3PO4] = de

0.5M to 5M)

Organic phase: 10 mM of extractant in dodecane, the extractant being the following compound (see paragraph 6.5 above):

The calculated values of the distribution coefficients D and the extraction percentages E (%) are reported in table 8.1 below:

[H3PO4] (in M) 5 3 1 0.5 Element M D E (%) D E (%) D E (%) D E (%) Fe 0.05 5 0.27 21 0.51 34 0.54 35 The <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Nd <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Gd <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 <0.001 <0.1 Dy 0.01 1 0.03 3 0.06 6 0.11 10 Yb 0.34 25 0.71 41.5 1.2 54 1.3 57

Table 8.1

The calculated values of the selectivity factors FS of each lanthanide

Ln with respect to Fe, denoted FSLn / Fe, are reported in Table 8.2 below:

{H3PO4] (in M) 5 3 1 0.5 Lanthanide Ln FSüi / Fe FSm / Fe Work FSLn / Fe The <0.1 <0.1 <0.1 0, l < Nd <0.1 <0.1 <0.1 0, l < Gd <0.1 <0.1 <0.1 0, l < Dy 0.6 0.1 0.1 0.2

Yb 20 3 2 2.5

Table 8.2

The calculated values of the selectivity factors FS of element Yb with respect to each element M, denoted FSyb / M, are reported in table 8.3 below:

[H3PO4] (in M) 5 3 1 0.5 Element M FSyb / M FSyb / M FSyb / M FSyb / M Fe 20 3 2 2.5 The > 200 > 200 > 200 > 200 Nd > 200 > 200 > 200 > 200 Gd > 200 > 200 > 200 > 200 Dy 35 23 18 12

Table 8.3

The results of Examples 13 to 15 show that the presence of an alpha branching of the phosphonate group or of the amide group makes it possible to efficiently and selectively extract Yb, for all the 10 molar concentrations of [H3PO4] (from 0.5 M to 5 M). We observe, in fact, that the lanthanides of atomic number lower than that of Yb (Ln = La, Nd, Gd, Dy) are not, or are little, extracted.

The extractants comprising an alpha branching of the phosphonate group or of the amide group therefore exhibit interesting performances for the extraction of Yb with good selectivity towards Fe. By increasing the molar concentration by extracting to values between 15 mM and 25 mM, Yb extraction performance is obtained which is established between 71% and 80%, while maintaining good separation factors (FSyb / Fe> 200) and this at high acidity ([H3PO4 ] = 5 M).

By comparing the results of Examples 13 and 14 with those of Example 15, it is observed that an extractant comprising an alpha branching of the phosphonate group (Ri = Oct in Example 13 or Ri = CH3 in Example 14) leads to improved Yb extraction performances compared to those of an extractant comprising an alpha branching of the amide group (Ri = CH ₃ in Example 15), in particular for low molar concentrations of [H3PO4] ( 0.5 M and 1 M). In particular, an optimum efficiency / selectivity is obtained for molar concentrations of [H3PO4] of 1M and 3M.

Furthermore, when the extractant comprises an alpha branch of the phosphonate group (Ri # H), it is observed that the extraction performance of Yb is improved when this branch is a methyl branch (Ri = CH3 in Example 14) relative to an n-octyl branching (Ri = Oct in Example 13).

BIBLIOGRAPHY [11 S. Ansarl et al., Chem. Rev., 2012,112,1751-1772 [2] H. Narita et al., Solvent Extraction Research and Development, Japan, 2013, 20,115121 [3J M. Iqbal et al., New J. Chem., 2012, 36,2048-2059

Claims (20)

1. Use of at least one compound which corresponds to the formula CLAIMS general (I) following: "2 R ₃ yO ^ _o j < _R4 (D in which - n represents an integer equal to 0.1 or 2, - R 1 and R 1 represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, C 1 to C 12 hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group, optionally branched, in Cj to Ca, - one among Ra and Ra corresponds to the following formula (II): O (II) in which Rs and Re represent, independently of one another, an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group, a cyclic, saturated or unsaturated, optionally branched hydrocarbon group, C3 to Ca, a hydroxyl group -OH or an alkoxyl group -OR, with R representing an aliphatic, saturated or unsaturated, linear or branched, C1 to C12 hydrocarbon group or a cyclic, saturated or unsaturated, optionally branched aliphatic hydrocarbon group , in C3 to Ca, and - the other among R3 and R «answers: . either to the following formula (II '): O II (H *) * ’·. in which Rs and R6 represent, independently of one another, an aliphatic, saturated or unsaturated, linear or branched, C1 to Cn hydrocarbon group, a cyclic, saturated or unsaturated, optionally branched, C ₃ to C hydrocarbon group , a hydroxyl group -OH or an alkoxyl group -OR ', with R * representing an aliphatic, saturated or unsaturated, linear or branched, C1 to Cn hydrocarbon group or a cyclic, saturated or unsaturated, optionally branched, aliphatic hydrocarbon group in C3 to Ce,. either to the following formula (III): O ^{(, li)} I ^? in which R? and Rs represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, C1 to Cn hydrocarbon group or a cyclic, saturated or unsaturated, optionally branched aliphatic hydrocarbon group, at C ₃ to Cs, as an extradant, to extract at least one rare earth from an aqueous phase in which said at least one rare earth is present, said aqueous phase further comprising phosphorlque acid. 2. Use according to claim 1, in which the compound corresponds to the following particular formula (l-a): OO ^(, ' ^a) R ₆ Ri R ₂ "e in which Rs and / or R6 represent a hydroxyl group —OH. 3. Use according to claim 2, wherein - one of Rs and Re represents a hydroxyl group -OH and the other of Rs and Re represents an alkoxyl group -OR, with R representing an alkyl group, linear or branched, C ₂ to Ce, advantageously G, and - Rs' and R6 represent, independently of one another, an alkyl group, linear or branched, in Q to Cio, advantageously in G. 4. Use according to claim 1, in which the compound corresponds to the following particular formula (i-b): OO _Rs -P _Y ° _r c. _N. ^R , (lb) ^R “Rt H, r, in which Rs and / or Rs represent a hydroxyl-OH group. 5. Use according to claim 4, wherein - one of Rs and R6 represents a hydroxyl group -OH and the other of Rs and Rs represents an alkyl group, linear or branched, C1 to Cio, advantageously in Ce, or an alkoxyl group -OR, with R representing an alkyl group, linear or branched, C ₂ to Ce, advantageously G, and - R? and Rg represent, independently of one another, an alkyl group, linear or branched, Ci to Cio, advantageously G. 6. Use according to any one of claims 2 to 5, in which R 1 and R 1 each represent a hydrogen atom. 7. Use according to any one of claims 2 to 5, in which R 1 and R ₂ each represents an alkyl group, linear or branched, C1 to Cio, advantageously C1 to G. 8. Use according to any one of claims 2 to 5, in which one of R 1 and R ₂ represents a hydrogen atom and the other of R 1 and R ₂ represents an alkyl group, linear or branched, in C1. to Cio, advantageously in Ci to Ce. 9. Use according to claim 8, wherein R ₂ represents a hydrogen atom. 10. Use according to any one of claims 1 to 9, in which the aqueous phase is an acid attack solution of a concentrate of a natural or urban mineral comprising said at least one rare earth. 11. Use according to any one of claims 1 to 10, in which the aqueous phase comprises at least 0.1 mol / L, advantageously from 0.2 mol / L to 8 moi / L, and preferably from 0.5 mol. / L to 5 moi / L, phosphoric acid. 12. Use according to any one of claims 1 to 11, wherein the extraction is carried out by the liquid-liquid extraction technique by means of an organic phase comprising at least 10 ³ mol / L, advantageously 5.10 ^%. mol / L to 1 mol / L, and preferably from 10 ² moi / L to 10 ¹ moi / L, of the compound in solution in an organic diluent. 13. A method of recovering at least one rare earth present in an aqueous phase, said aqueous phase further comprising phosphoric acid, said method comprising the following steps: a) extracting said at least one rare earth from the aqueous phase by bringing the aqueous phase into contact with an organic phase comprising at least one compound as defined in any one of claims 1 to 9, then separation of the aqueous phase of the organic phase; and b) back-extracting said at least one rare earth present in the organic phase as obtained at the end of step a) by bringing this organic phase into contact with an aqueous phase, then separating the organic phase from the aqueous phase. 14. The method of claim 13, wherein, during step a), at least one salt is added to the aqueous phase, said at least one salt advantageously being sodium nitrate. 15. The method of claim 14, wherein the molar concentration of salt (s) is from 0.01 mol / L to 4 moi / L, advantageously from 0.05 mol / L to 3 mol / L and, preferably, from 0.1 mol / L to 2 mol / L 16. A method according to any one of claims 13 to 15, wherein the aqueous phase is an acid attack solution, by phosphoric acid, of a concentrate of a natural or urban mineral comprising said at least one earth. rare. 17. Compound which corresponds to the following special formula (l-a): OO “ ₅ -Γυ ° υ ' ^! \ ' ^ι, 5' r ₁ r ₂ V in which - R 1 and R 1 represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, Ci to Cu hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group, optionally branched, in Ca to Ce, - one of Rs and ββ represents a hydroxyl group -OH and the other of Rs and Re represents an aliphatic, saturated or unsaturated, linear or branched, C1 to Cu, a cyclic, saturated or unsaturated hydrocarbon group, optionally branched, in Ca to Ce, a hydroxyl group -OH or an alkoxyl group -OR, with R representing an aliphatic, saturated or unsaturated, linear or branched, C1 to Cn hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group , possibly branched, in Ca to Ce, and - Rs 'and Re' represent, independently of one another, an aliphatic, saturated or unsaturated, linear or branched, C1 to Cn hydrocarbon group, a cyclic hydrocarbon group, saturated or unsaturated, optionally branched, in Ca to Ce, a hydroxyl group -OH or an alkoxyl group -OR ', with R' representing an aliphatic, saturated or unsaturated, linear or branched, C1 to Cn hydrocarbon group or a cyclic, saturated or unsaturated, optionally branched aliphatic hydrocarbon group, in Ca to Ce. 18. A compound according to claim 17 wherein - one among Rs and Re represents a hydroxyl group -OH and the other among Rs and R6 represents an alkoxyl group -OR, with R representing an alkyl group, linear or branched, C2 to Ca, advantageously C4, and - Rs' and R6 represent, independently of one another, an alkyl group, linear or branched, C4 to Cio, advantageously of Ca. 19. Compound which corresponds to the following special formula (l-b): O O R ₅ -J''Y ° 'Y'C ^. R ₇ (lb) ^r 6 R _x R2 R ₈ in which - R 1 and R 2 represent, independently of one another, a hydrogen atom, an aliphatic, saturated or unsaturated, linear or branched, C 1 to C 12 hydrocarbon group or a cyclic, saturated or unsaturated aliphatic hydrocarbon group, optionally branched, in Ca to Ce, - one of R _s and Re represents a hydroxyl group -OH and the other of Rs and R6 represents an aliphatic, saturated or unsaturated, linear or branched, C 1 to C 12 hydrocarbon group, a cyclic, saturated or unsaturated hydrocarbon group , optionally branched, in Ca to Ca, a hydroxyl group -OH or an alkoxyl group -OR, with R representing an aliphatic, saturated or unsaturated, linear or branched, C 1 to Cu hydrocarbon group or a cyclic, saturated or aliphatic hydrocarbon group unsaturated, optionally branched, C ₃ to C ₈ , and - R7 and Rg represent, independently of one another, a hydrogen atom, 5 an aliphatic, saturated or unsaturated, linear or branched hydrocarbon group, in Ci to C12 or a cyclic, saturated or unsaturated, optionally branched, C ₃ to C ₈ aliphatic hydrocarbon group. 20. A compound according to claim 19 wherein 10 - one of Rs and Rg represents a hydroxyl group -OH and the other of Rs and Rg represents an alkyl group, linear or branched, C4 to C10, advantageously Cg, or an alkoxyl group -OR, with R representing an alkyl group, linear or branched, C ₂ to C ₈ , advantageously C ₄ , and - R7 and Rg represent, independently of one another, an aikyle group, linear or branched, in Q to Cio, advantageously in Cg.