FR2604919A1 - Difunctional organophosphorus extracting agents and polymers for uranium recovery - Google Patents

Abstract

Agent for extracting heavy metals in ionic form, from their acidic solutions, which is in the form of an organic solution of a compound comprising a phosphine oxide group and a phosphoric or thiophosphoric group which are linked by an appropriate spacing group.

Description

 The present invention relates to the preparation of bifunctional phosphoric acid esters of a trialkyl phosphine oxide and their application as synergistic extraction agents of extraction agents used for the recovery, from solutions and in particular of phosphoric solutions of uranium.

The recovery of uranium from its inorganic salts is carried out by releasing the metal by dissolution in an acid or a base. This recovery is particularly interesting from phosphoric solutions from phosphate rocks. Large quantities of phosphate rock are treated annually. Raw phosphoric acid is therefore a considerable source of uranium. However, the phosphate ligand strongly competes with metal, and the extraction of it from concentrated solutions of phosphoric acid proves difficult. The processes developed in Oak-Ridge
National Laboratories include the recovery of U (VI) using a synergistic mixture of di- (ethyl hexyl) phosphate (DEHPA) and trioctyl phosphine oxide (TOPO) (See FJHurst, Recovery of Uranium Form Wet-Process
Phosphoric Acid by Solvent Extraction, AIME Ann. Meeting,
Las Vegas (February 22-26, 1976); or DS Flett, Solvent
Extraction in Hydrometallurgy, Chem. & Ind., Pp. 706-712 (September 3, 1977)).

Recently, several patents have described adaptations of this original DEHPA / TOPO process, as well as improvements in this process; SH Chevalier, JC Gautfer,
CR Sorfaux, Synthesis Process of Phosphine Oxides
Tertiary and New Tertiary Phosphine Oxides,
FR 81 12593 (June 20, 1981); C. Ginisty, M. Hammer, B.

Manborgne, Process for the Recovery of Uranium -Prest in Phosphoric Acid Solutions, FR 80 24253 (November 11, 1980); P. Blanquet, F. Ricalena, Compochians Exchangers of Metallic Cations, FR 80 08963 (April 21, 1980)
J. Ball, G.Ledour, Perfected Process for the Production of Oxides of Tertiary Phosphines, FR 73 44642 (December 12, 1973).

 The present invention relates to the synthesis of monomeric and polymeric, phosphorus, bifunctional extraction agents for the selective recovery of uranium, and other heavy metal ions, from aqueous solutions.

dans laquelle R1 et R2 sont chacun un alkyle, cycloalkyle, aryle ou aryle substitué, R1 pouvant être identique à R2, n est un nombre entier de 1 à 20 et de préférence de 1 à 9, Y est oxygène ou soufre ; m peut varier de 1 à 10 et de préférence entre 1 et 5, X est oxygène ou soufre, R3 est un alkyle, cycloalkyle, aryle ou aryle substitué, et peut être vinyl-4 benzyle ou méthylpolystyryl benzyle. Les valeurs préférées de m sont : 1 ou > , 3 pour n = 1, 1 à 10 et de préférence 1 à 5, lorsque n = 2.These phosphorated bifunctional molecules are constructed in such a way that two fixing sites, namely a phosphine oxide group (P = O) and a phosphoric acid group (-PO3H) or a thiophosphoric acid group (-POS2H), are linked by a hydrocarbon bond. appropriate. These bifunctional compounds are represented by the general formula I

wherein R1 and R2 are each alkyl, cycloalkyl, aryl or substituted aryl, wherein R1 may be the same as R2, n is an integer of 1 to 20 and preferably 1 to 9, Y is oxygen or sulfur; m may be from 1 to 10 and preferably from 1 to 5, X is oxygen or sulfur, R3 is alkyl, cycloalkyl, aryl or substituted aryl, and may be 4-vinyl benzyl or methylpolystyryl benzyl. The preferred values of m are: 1 or>, 3 for n = 1, 1 to 10 and preferably 1 to 5, when n = 2.

 The novel compounds according to the present invention are prepared by a series of reactions in which a common intermediate, cyclophosphoro acetone enediol chloride (ECPC), prepared according to the method of F. Ramirez (F Ramirez, JF Mareck and I. Ugi J. Am Chem Soc.

Flight. 97, p. 3815 (1975)) is reacted in two successive stages with two alcohols, one having the phosphine oxide or thiophosphine group, and the other comprising the phosphoric or thiophosphoric acid group.

The triester can be cleaved to selectively remove the acetone group, thereby providing the desired diesters as shown in Scheme 1.

<Tb>

CH30, <SEP> X <SEP> ROH <SEP> CH3CO <SEP> \
<tb><SEP> / X <SEP> ROH
<tb> II <SEP> P <SEP> II <SEP> P
<tb> R1OH <SEP> H2O <SEP>, C
<tb><SEP> BSE
<tb><SEP> v13 <SEP>!
<tb><SEP> H <SEP> i
<tb><SEP> O = P-OR
<tb><SEP> OR
<Tb>
Diagram 1.

An important step in this process is the synthesis of the bifunctional molecules bearing the hydroxyphosphine oxide groups separated from each other by a hydrocarbon chain, for example hydroxymethyl dihexyl phosphine oxide (2) synthesized by condensation of dihexyl phosphine oxide (1) and formaldehyde. Compound (2) can then be converted to bromomethyl dihexyl phosphine oxide (3), which in turn can be converted to thiomethyl dihexyl phosphine oxide (4).

The bromomethyl dihexyl phosphine oxide can be reacted with diols to give a distilled hydroxyalkyl phosphine oxide, for example (6-hydroxyhexyloxymethyl) dihexyl phosphine oxide (5).

The hydroxyalkyl phosphine oxide spacer (7) is obtained after reaction with methoxy-bromodecane and dihexyl phosphine magnesium oxide bromide to give (6). (6) can be converted to (7) by cleavage of the methoxy group with boron tribromide.

When carrying out syntheses according to Scheme 1, the alcohol of the first stage is usually of the hydroxyalkylphosphine oxide type (for example the compounds (2), (5) and (7)). When the group Y of the general formula I is sulfur, it is necessary to react in the first stage a thiophosphine oxide (for example the compound (4)) -
In the second stage, almost all the alcohols can be used; the judicious choice of the length of this alcohol, and its structure can be used to adjust important parameters of the bifunctional reagents as solubility, activity, stability.

 Cleavage of the acetone enediol group is usually carried out using a weak base such as pyridine, triethylamine. In the case of the thio derivatives (I, Y = S), care should be taken to apply weaker bases, for example N, N-dimethyl aniline, in order to protect against premature elimination of the thioalkyl group. Thio substituents on phosphorus (group X) can be introduced into oxygen carrier compounds (I, X = O) by common methods, for example by reaction with tetraphosphorus decasulfide (P4S10).

The preparation of a typical extractant, octyl phosphate and dihexyl methylol phosphine oxide (8) is shown in Scheme

<tb> 2. <SEP> CM
## EQU1 ##
<tb><SEP> -f- <SEP> (C6H1) 2 <SEP> p
<tb><SEP> CH3 / <SEP> 0 <SEP> Cl <SEP> CHzOH <SEP> Cl3 / <SEP> C <SEP> b
<tb><SEP> CH2OH <SEP> CH3
<tb><SEP> CH2
<tb><SEP> t <SEP> \ <SEP> CH2
<tb><SEP> (C6H13) z <SEP> -P = O
<tb><SEP> C8Ft170fiS
<tb><SEP> E13N
<tb><SEP> Scheme <SEP> 2. <SEP><SEP> // <SEP> ≈ <SEP> 3llO <SEP> CH3O
<tb><SEP>'' I
<tb><SEP> C6Hi3-P- <SEP> CFI2-OP <SEP> -OI-C-CI3
<tb><SEP> C6M13
<tb><SEP> C6H13 <SEP> D \
<Tb>

<tb><SEP>'o<SEP> 1Pyridff <SEP>(C6H3> 2- <SEP> P \ PI <SEP> p,
<tb> (C6H13) 2 <SEP> Ps <SEP> Pyridine <SEP> + H2O <SEP> p <SEP> I ~ Pvridina <SEP> (C, HI,), - <SEP>?
<tb><SEP> I <SEP> E13N <SEP> CH2-O- <SEP> 8
<tb><SEP> CH3-C-CHO <SEP> t.H + 3 <SEP> C4 <SEP> OH <SEP> I
<tb><SEP> It <SEP> I
<tb><SEP> O <SEP> CH3
<Tb>
The synthesis of monomeric phosphocycloenediols from conventional vinyl alcohols, for example hydroxymethylstyrene or hydroxyethyl acrylate, is described in Scheme 3.

<Tb>

CH3C / O \ <SEP> -CH20Hc
<tb><SEP> It <SEP> P <SEP> H + <SEP> CH <SEP> OH <SEP> - <SEP> C <SEP> -C
<tb>0H3'C \ O / <SEP> O-CH2 <SEP> 2
<tb><SEP> CH2
<tb><SEP> 10 <SEP> O \ <SEP> // O <SEP> CH3N <SEP> / 0 <SEP> O
<tb><SEP> it <SEP> oPs <SEP> + <SEP> CH2 = CH-COOCH2CH20H <SEP> C <SEP> / P \
<tb><SEP> CHJ / C \ 0
<tb><SEP> CH3 <SEP> CH3 <SEP> C \ 0 / <SEP> O
<tb><SEP> o <SEP> CH2
<tb><SEP> It <SEP> I
<tb><SEP> CH2 <SEP> = CH-CO-CH2
<tb><SEP> Schema <SEP> 3.
<Tb>

 The monomeric acetone diol phosphine oxide (9), (10), (11) can be easily homopolymerized or copolymerized to give polymeric phosphine oxides (after removal of the acetone diol blocking group, or they can be reacted with another alcohol to give polymerizable phosphoric acid diesters according to Scheme 4.

 The synthesis of polymeric support bifunctional phosphine oxide phosphoric acid esters is shown in Scheme 5. First, the dihexyl hydroxymethyl phosphine oxide (2) is reacted to give the dihexyl acetolneenediol cyclophosphorohydroxymethyl phosphine (14), which is then reacted with a polymeric alcohol (PS represents a polysulfone) to obtain, after hydrolysis, a phosphoric acid ester of polymeric phosphine oxide (16).

Figure 4.

<tb> ea, c / o \ <SEP> / 0 <SEP>'o<SEP>"Q
<tb><SEP><SEP> / o <SEP> 6 <SEP> (C6H13) 2P \ '<SEP> (C6H3) 2P \
<tb><SEP> CH2OH <SEP> CM2
<tb><SEP>H;<SEP> 00C2C2-2 <SEP> 2 <SEP> Cz <SEP> 2
<tb><SEP> Y <SEP> O <SEP> 0
<tb><SEP> it <SEP> I
<tb><SEP> CH2 <SEP> = CH-CO-CH2-C12-OP = 0
<tb><SEP> CH3- <SEP> C-CH-O
<tb><SEP> Schema <SEP> 5. <SEP> It <SEP> I
<tb><SEP> Y <SEP> J <SEP> Y <SEP> CH3
<tb> O <SEP> O <SEP> (C6H13) 2 <SEP>: HZOH <SEP> O
<tb> \ C / <SEP> p <SEP> + <SEP> O <SEP> CH3 <SEP> C <SEP> \ <SEP> //
<tb><SEP> It <SEP> (C6HI3) 2% H2OH <SEP> It <SEP> P
<tb> C \ O / <SEP> \ CI <SEP> CI <SEP> 1 <SEP>wC> O / \ Ó <SEP> 0
<tb><SEP> 14 <SEP>(C6't13) 2
<tb><SEP>}<SEP> Et3N <SEP> eCHzOH
<tb><SEP> HO
<tb><SEP> I <SEP> It
<tb><SEP>} CH20 <SEP> G <SEP> CH2-0 <SEP> - <SEP> | <SEP> -O- <SEP> C <SEP> - <SEP> C <SEP> -CH3
<tb><SEP> ~~~~~~~~ <SEP> I
<tb><SEP> \ <SEP> QO <SEP> ICgH <SEP> P <SEP> -CH2 <SEP> -O <SEP> CH3
<tb><SEP> I- <SEP> / P \ <SEP> It
<tb><SEP> O <SEP> ck <SEP> O <SEP> O
<tb><SEP> CH-P '<SEP> L5
<tb><SEP> 2 <SEP> CH2
<Tb>
When an insoluble polymeric alcohol (PS = polystyrene, for example Amberlite XE-305) is used, an insoluble polymeric phosphoric acid phosphoric acid ester (16, PS = polystyrene) is obtained.

EXAMPLE 1
Preparation of the phosphorylation reagent
Cyclophosphoro acetoin enediol chloride

The procedure according to F. Ramirez et al., J. Am. Chem.

Soc. 97, p. 3815 (1975), is carried out in four stages from A to D.

A. 88.8 g of freshly distilled diacetyl (1.03 M) are added to a stirred solution, freshly distilled, of 12.7 g (1.03 M) of trimethyl phosphate in 150 ml of CH 2 Cl 2 at a rate of such that the temperature is maintained between 10 and 150C. The solution is stirred at this temperature for 3 hours, the solvent is removed and the product, trimethyl cyclophosphate and acetone enediol, is distilled (boiling point 3.5 mm Hg = 83-84 C, 93% yield). ).

NMR (CDCl 3): d = 3.68 (s), 3.52 (s), 1.82 (s).

 During a second preparation according to F.

Ramirez (Synthesis, 819, 1976), the product is not isolated but is used for the next stage directly.

B. The reaction mixture of A is used as a raw material. 600 ml of freshly distilled acetonitrile were added to P 2 O 5, and 135.5 g of freshly distilled diacetyl were added dropwise at a rate keeping the temperature at about 45 ° C.

After stirring for 2 hours at room temperature, the solvent is removed and the product is distilled (152 g, 89.5% yield, boiling point below 0.8 mm Hg = 92 ° -980 ° C.).
NMR (CDCl3) s = 3.94, 3.79 (d, 3H), 1.93 (s, 6H).

C. The product from Stage B is dissolved in 400 ml of benzene, and 210 g of pyridine is added. This mixture is refluxed for 7 hours and left overnight with stirring. A white precipitate is obtained. The solvent is decanted and the residue is allowed to dry after rinsing with benzene at 35 ° C at 2 mm Hg for 4 hours The residue, N-methyl-pyridinium 4,5-dimethyl-2-oxido-2-oxo , 3,2-dioxa phosphate, weighs 190 g (78% yield).

D. The product of reaction C is suspended in 800 ml of dry benzene, 90 ml of phosgene is slowly added to this solution, and the mixture is left stirring for about 50 hours. At first there is a release of CO2. When the reaction is complete, the N-methyl-pyridinium chloride is filtered (dry) and the solvent is removed. The product, cyclophosphoro acetone enenediol chloride, is distilled (boiling point under 2 mmHg = 850-860C) 79.5 g (yield 60%) are obtained.

NMR (CDCl3): & 1.99 singlet.

 The total yield from the starting trimethylphosphite is 50%.

EXAMPLE 2
Preparation of 2-ethylhexyl phosphate and dihexylmethylolphosphine oxide

A. 17 g (0.1 M) of cyclophosphoro acetone enediol chloridate in 75 ml of dry CH 2 Cl 2 are placed in a 250 ml flask and stored under nitrogen. The solution is cooled to OOC, and 15.6 ml (13 g, 0.1 M) of 2-ethyl hexanol, together with 13.9 ml (0.1 M), are slowly added over 15 minutes. of triethylamine in 50 ml of CH2Cl2. The ice bath is removed and the solution is stirred for 1 hour. A solution of 24.9 g (0.1 M) of dihexyl methylol phosphine oxide and 13.88 ml (10.1 g, 0.1 M) of triethylamine in 50 ml of CH 2 Cl 2 is slowly introduced therein, and it is left overnight (20 hours) under agitation.The solution is filtered (----- Et3NHCl and the thread
3t (as well as CH2Cl2 which is used to rinse the precipitate) are evaporated. The residue is dissolved in a small volume of CH2Cl2. More crystals are filtered and eliminated. The solution is rinsed with HCl (5%, 2 x 150 ml) and with water (2 x 150 ml), dried (Na 2 SO 4), treated with activated charcoal and the solvent is removed. The residue (50.15 g) contains, in addition to the product, dihexyl methylol phosphine oxide and acetonyl phosphate and di (2-ethylhexyl). The reaction mixture is separated by flash column chromatography (hexane / ethyl acetate). The first fractions are eluted with 20% hexane in ethyl acetate and found to contain acetoinyl phosphate and di (2-ethylhexyl).

NMR (CDCl 3): # = 4.82 (m, dd of q, 1H, PO-CHCH 3), 4.03
(m, d of t, 4H, O-CH 2 -CH), 2.25 (s, CH 3 -C, 3H), 1.80-0.8
(m, 33H).

It is found that the following fractions, eluted with 10% hexane in ethyl acetate, contain the product, 2-ethylhexyl phosphate of acetoinyl and dihexylmethylolphosphine oxide.

NMR (CDCl3) = 4.81 (doublet of a quartet, J1 = 6.4Hz, J2 1.6Hz, 1H, C-CH), 4.31 (q.dded, J1 = 10.4Hz, J2 = 4.8 Hz, O 2 H, P-CH 2 -O), 4.03 (q d of d, J 1 = 10.4 Hz, J 2 = 4.8 Hz, 2H,
O-CH -). 2.23 (s, 3H, CH = 0 2.03-0.81 (m, 44H).

 2 CH3).

+ + m / e 510.336 (M +), 453 2735 (M-C4Hg), 423.2756 (M-CO (CH3) CH (CH3) O). 3.97.211 (M + C8H17), 383.176 (M + C8H17O), 311.153 (M + H3COCH3);
C8H17). The last fractions are eluted with 5% MeOH in ethyl acetate and contain dihexyl methylol phosphine oxide.

B. 1.5 g (3 mM) of the ethyl 2-hexyl phosphate triester of acetoinyl and dihexyl methylol phosphine oxide are dissolved in 25 ml of water, 25 ml of pyridine and 0.8 ml ( 6mM) of triethylamine. This mixture is stirred for 92 hours at room temperature (150 ° C.). Solvents are removed (oil pump). The residue is the triethyl ammonium salt of the acid (yield: 100%).

NMR (CDCl 3) b = 4.16 (t J = 6.8 Hz, O-CH 2 -P = 0.2H), 3.84 (d of d,
J1 = 3.9 Hz, J2 = 4.4 Hz, CH-CH2PP, 2H), 3.11-2.91 (broad t J1 = 6.8 Hz,
J24.9Hz, N, HN- (CH2-) 3), 1.81-0.8 (m, 50H, C7H15 + 2 (C6H13) + 3CH3).

This triethylammonium salt is converted to the acid by dissolving in CH2Cl2 and washing the solution with a 0.5M solution of HCl.

EXAMPLE 3
Synthesis of the Benzylpolystyrene Derivative XE-305 of Dihexyl Methylthio Phosphine Oxide
A. Chloromethylated Amberlite XE-305 (chlorine content 13.05) is swollen in water and 2.7 molar equivalents of thiourea are added thereto. The mixture is heated at reflux for 16 hours and then cooled to room temperature. The isothiourea polymer is filtered off, rinsed with water, HCl (1%), acetone, and dried in air and in a vacuum oven.

est mis à gonfler dans 25 ml d'une solution à 10% de NaOH. Le mélange est chauffé à 800C pendant 10 jours. Le polymère est séparé par filtration, est rincé avec de l'eau, puis avec HCl 10%, et finalement avec de l'eau et du méthanol. On le sèche dans un four à vide (330C). Après séchage le poids du thiométhyl polymère est de 8,43 g (rendement 72%).Microanalysis
Before reaction: N 7.03% S 9.57% Cl 10.59%
After reaction: N 7.23%
B. The isothiourea polymer (with

is swollen in 25 ml of a 10% solution of NaOH. The mixture is heated at 800C for 10 days. The polymer is filtered off, rinsed with water, followed by 10% HCl, and finally with water and methanol. It is dried in a vacuum oven (330C). After drying, the weight of thiomethyl polymer is 8.43 g (72% yield).

Microanalysis
Calculated: C 72.00% H 6.66% S 21.33%
Found: C 80.63% H 7.05% S 10.63%
C. 2 g of XE-305 are swelled in 25 ml of methanol.
CH 2 SH. It is added together with 10 ml of
10% NaOH, 1.5 g (4.8 mM) dihexyl bromomethyl phosphine oxide. The solution is left at room temperature for 10 days. The polymer is filtered off, rinsed with water, 5% HCl, water, methanol, CHCl 3, methanol and dried in a vacuum oven (30 ° C.). benzyl-polystyrene type XE-305 dihexyl ether methylthio phosphine, weighs 2.91g.

Microanalysis
Calculated: C 68.86% H 9.56% S 8.74% P 8.46%
Found: C 77.16% H 9.04% S 7.05% P 3.90%
The infrared spectrum shows the disappearance of the SH signal at 2600 cm 1 and the appearance of peaks at 1150 and 1200 cl, corresponding to the trialkyl phosphine oxide function.

EXAMPLE 4
Synthesis of acylmethyl polystyryl methylol phosphate and dihexyl methylol phosphine oxide.

1.3 g of hydroxymethylated Amberlite XE-305 is swollen for 2 days in CH 2 Cl 2. A solution of 1.7 g (0.01 M) of diol cyclic phosphorochloridate in 25 ml of CH 2 Cl 2 and a solution of 1.3 ml (0.01 M) of triethylamine in 25 ml of CH 2 Cl 2 are added simultaneously. . The mixture is allowed to stand for 20 hours and another portion of 1 g of reagent is added and the reaction mixture is left for 60 hours. The polymer is filtered off and rinsed with absolute MeOH. Then it is dried for 24 hours in a vacuum oven (350C). It weighs 1.92g. For a polymer of 5.29 meq / g of functional OH, the percentage of the reaction is 68%. The mother liquor contains unreacted reagent.

25 g of CH.sub.2 Cl.sub.2 are added to this polymer. 0.89 g of dihexyl methylol phosphine oxide and 0.46 ml of triethylamine are added thereto in CH 2 Cl 2 and the mixture is left stirring for 400 hours. The polymer is filtered off, rinsed with CH 2 Cl 2, MeOH, 0.1M HCl, water, methanol and CH 2 Cl 2. It is dried in an oven (400 ° C. at 20 mm Hg) and a weight of 0.985 g is found, which means that there is no reaction.

EXAMPLE 5
Hydroxymethyl polysulfonyl phosphate of acetoinyl and of dihexyl methylol phosphine oxide.

A. 2.47 g (5.3 mM) of hydroxymethylpolysulfone and 0.75 ml (5.3 mM) of triethylamine in 25 ml of CH 2 Cl 2 are added slowly to an ice-cold solution of 12 g (7 mM). ) chloridate in 25 ml of CH2Cl2. The solution is allowed to warm to room temperature and is left standing for 1 hour. 1.4 g (5.6 mM) of dihexyl methylol phosphine oxide in 25 ml of CH 2 Cl 2 are added thereto and the solution is stirred at ambient temperature for 41 hours. Then rinsed with 5% HCl solution (2 x 25 ml) and poured dropwise into 500 ml of hexane. A fluffy precipitate is obtained. It is separated by filtration, washed with hexane and dried (vacuum oven). It weighs 2.75g.

et de

sont apparus. The NMR of the polymer indicates that all the CH 2 OH signals have disappeared, and that new signals of

and of

appeared.

According to the integration, it is estimated that the reaction is of the order of 85% (in the original polymer, 65% of the monomers contain a CH 2 OH group).

The infrared spectrum of the polymer (KBr) shows that, besides the peaks of the polysulphone, there are two new bands at 1735, 1725 cm 1 and 1010 cl 1. These are peaks characteristic of the triester function, and more particularly of the ketonic function C = O.

B. Hydrolysis of compound 15
During a typical hydrolysis experiment, 2.45 g of polymer of Stage D are dissolved in 100 ml of CH 2 Cl 2, a solution of 1.5 ml of triethylamine in 20 ml of water is added and the mixture is stirred. mixing for 16 hours.

The layers are separated, and the bottom layer is rinsed with 5% HCl and water. Then poured into 500 ml of hexane. The white precipitate that occurs is filtered, washed with hexane and dried, first in the air and then in a vacuum oven.

et il est apparu un nouveau pic à 1680 cm 1, caractéristique de la fonction -P-OH.NMR (CDCl 3) shows the disappearance of the peaks of the CH (CH 3) COCH 3 ester group. Infrared (KBr: the peak at 1725 cm has almost disappeared (it remains a little of the group

and there appeared a new peak at 1680 cm 1, characteristic of the -P-OH function.

A triester hydroyse test with (CH3) 4N OH remained unsuccessful. 2.5 ml of a 25% solution of tetramethylammonium hydroxide are added to the polysulfone solution in CH 2 Cl 2, and a gel is immediately formed. The polymer does not redissolve in CH2Cl2 or N-methylpyrrolidone.

EXAMPLE 6
Synthesis of 4-methylol styrene phosphate of acetoinyl and of dihexyl methylol phosphine oxide.

To a solution of 7.72 g of chloridate (0.045 M) in 25 ml CH2Cl2 cooled with ice. This solution is stirred at ambient temperature for 45 minutes, then 12 g (0.048 M) of dihexyl methylol phosphine oxide and 6.3 ml (0.045 M) of triethylamine in 25 ml of CH 2 Cl 2 are slowly added and the mixture is left stirring. at room temperature overnight. The solution is filtered off and the triethylammonium chloride is removed. The filtrate is rinsed with 5% HCl (3 × 50 mol), Na 2 CO 3% (1 × 50 ml) and
5% NH4Cl (1 x 50 ml). Dry (MgSO4) and remove the solvent.

The residue is an almost pure product. NMR (CDCl3): in addition to the peaks of di- (p-vinylbenzyl) and acetoinyl phosphate which are almost the same here, there are peaks at 4.25 (q, J = 6Hz, 2H, O- CH-P = O) and 1.7-0.8 (m, 29H, 2C6H13 + CH3).

EXAMPLE 7
Acetoinyl phosphate and bis (methylolstyrene).

2.28 g (0.017 M) of p-vinylbenzyl alcohol and 2.5 ml (0.017 M) of triethylamine in 25 ml of CH 2 Cl 2 are slowly added in an ice-cold solution of 3.04 g (0.018 g). M) chloride in 25 ml of CH2Cl2. This solution is allowed to warm to room temperature and is left stirring for 1 hour. 2.28 g (0.107 M) of p-vinylbenzyl alcohol and 2.5 ml (0.017 M) of triethylamine dissolved in 25 ml of CH 2 Cl 2 are added and the mixture is left stirring overnight. This solution is rinsed with 5% HCl (2 x 50 ml) and with water.

The solvent is dried (MgSO4) and removed. The residue is almost pure product (yield: 88%).

 NMR (CDCl 3): Hz = 7.46-7.31 (m.H, hydrogenaromatic 6.70 (d of doublet, J1 = 17.6Hz, J2 = 10.7Hz, 2H, CH =), 5.74 ( d, J = 17.5Hz, 2H, CH = CH), 5.26 (d, J = 10.9Hz, 2H, CH = CH) ,.

5.06 (dd, J1 = 8.5Hz, J2 = 2.6Hz, 4H, CH2-OP), 4.70 (q, J = 6.8Hz, 1H, -CHOP), 2.14 (s, 3H). , CH3-C = O), 1.38 (d, J = 7Hz, 3H, CH3-CH).

CH3 O
Mass Spectrum: m / e 401.003) (M +), 133.06, 117.073, 71.085.

The compound polymerizes when it is dropped.

EXAMPLE 8
2-acryloyl ethyl acetoinyl and dihexyl methylol phosphine oxide.

1.36 g (0.012 M) of 2-hydroxyethyl acrylate and 1.65 ml (0.012 M) of triethylamine in 25 ml of CH 2 Cl 2 are slowly introduced into an ice-cold solution of 1.98 g (0.012 M 3). This solution is allowed to warm to room temperature and stirred for 1 hour.

2.92 g (0.012 M) of dihexyl methyl methyl phosphine oxide and 1.65 ml (0.012 M) of triethylamine in 25 ml of CH 2 Cl 2 are then introduced and the mixture is left stirring overnight.

Most of the solvent is removed, and 50 ml of ether are added. The white precipitate (Et3NH + Cl) is separated by filtration. The solution is rinsed with 5% HCl (2 × 50 ml), and with 5% NH 4 Cl, dried (MgSO 4), and the solvent is removed. The residue (4.9 g, 74%) constitutes the product.

NMR: (CDCl 3) of the alcohol CH 2 = CH-COOCH 2 CH 2 OH: 5 = 6.57- 5.77 (ABx spectrum, J 1 = 16.6 Hz, J 2 = 14.2 Hz, J 3 = 2.9 Hz, 3H
CH2 = CH-), 4.29 (d, J1 = 6.1Hz, J2 = 4Hz, 2H, CH2OH), 3.85 (dd, J1 = 5.1Hz, J2 = 2.2Hz, 2H, CH2O-C = 0). 2.27-2.11 (wide s, 1H, OH) the last peak disappears when D20 is added.

NMR: (CDCl3) triester: & 6.57-5.92, similar pattern to that of alcohol; 4.84 (q, J = 7Hz, 1H, O-CH-CH 3). 4.43 O 4.21 (m, CH 2 CH 2 O-PO-CH 2 -P, 6H), 2.22 (s, 3H, CO-CH 3), 1.46, 1.34 (d, J = 10.1 Hz, 3H, -CH-CH3), 1.94-0.81 (m, 26H, aliphatic hydrogens).

This compound polymerizes when it is dropped and heated.

EXAMPLE 9
Extraction of U
The reagent used is 2-ethyl hexyl phosphate and dihexyl methylol phosphine oxide (R252).

 Solutions of R-252 in dodecane (optionally CHCl3) are mixed for 10 minutes (by stirring with a magnetic stir bar), with solutions of U (VI) (UO2Cl2) in phosphoic acid. 250C; the concentration of R-252 varies from 0.0042 M to 0.4 M, whereas that of U usually used for specific experiments is 1000 g / ml and 5000, 10 000 and 20 000 Rg / ml. The PO4H3 concentration ranges from 2 to 14.7 M and the organic / aqueous ratio is 1.

The two phases are separated and the concentration of U in the aqueous phase is determined by ray fluorescence
X at 6-4 Kev of the Fe Ks band. The excitation source is a Siemens X-ray lamp. Duplicates (500 ssl) of each sample are analyzed twice, read time: 60 seconds; detection limit: 3 ppm.

Usually, when working with dodecane, a middle phase is obtained during extraction, apparently the L U complex.

The effect of temperature on the extraction of U by R-252 is determined in three experiments at 250, 400 and 600C.

Regeneration of the reagent R-252 is carried out by extraction of the organic phase which contains the complex LU, with
8M H3PO4, 5% NaHCO3 or (NH4) 2 CO3 1M. The recycling of the reagent is controlled by its use after regeneration for a second extraction. Due to the solubility difficulties of the LU complex in dodecane, it is difficult to regenerate and recycle this solvent. This is why we carry out a series of experiments: extraction, regeneration and recycling in CHCl3 instead of dodecane.

Extractions by R-252 of U in the presence of other metal cations: Fe 2+ Fe 3+ Cu 2+ and Cd are carried out in
H3P042 M and 8 M containing 1000 μg / ml U and M4 each, and R-252 0.1 M in dodecane.

The extractive properties of the R-252 polymer vis-à-vis
U are examined by mixing solutions of the polymer in
CHCl3 (0.05 and 0.01 M) with 1000 μg / μl of U in 2M H3PO4.

It results from the contact between the polymer and the aqueous phase that it precipitates in the form of swollen white substance, which hinders the separation of the two phases.

The applicant has carried out in its laboratories comparative experiments with the known synergetic system
DEHPA / TOPO and the DEHPA / PTX-11 system (PTX-11 is hexyl ether S-octylthiomethyl phosphine), using DEHPA
/ 0.5M, TOPO 0.1 / 0.2M and TOPO 0.1M, DEHPA 0.1 / 0.4M years of dodecane with 1000g / ml of U in H3PO4 2M.

EXAMPLE 10
Action of the concentration of the reagent on the extraction.

The efficiency of the extraction of uranium by the reagent at different concentrations of the latter in the dodecane used as diluent, is demonstrated and is shown in Figure 1, for solutions of 4, 6 and 8 molar H3PO4 with U (VI) at the concentration of 1000 ppm. Figure 1 shows the distribution factors of uranium between the dodecane and H3PO4 phases.

The complexed metal ion is put into the form of a strong acid solution, for example phosphoric, hydrochloric, nitric or sulfuric, which can precipitate the metal in the form of powder or sponge.

EXAMPLE 1 1
Action of phosphoric acid.

The exact chemical structure of the uranyl moiety in phosphate media is highly dependent on the concentration of
H3PO4.

Accordingly, Figure 2 shows the distribution factors for U (VI) extraction with 0.01 M, 0.1 M and 0.4 M R-252 in dodecane. With the highest concentration of 0.4 M, the reagent is still able to transfer 50% of the metal into the organic phase, even from 12 M phosphoric acid.

EXAMPLE 12
Comparison with other reagents.

The mixture of commercial synergistic reagents DEHPA and TOPO is compared with R-252 under the same extraction conditions. The highly synergistic mixture DEHPA and PTX-11 is also compared (see FIG. 3). The superiority of the new bifunctional reagent for the extraction of uranium on these synergistic mixtures is evident.

EXAMPLE 13
Action of the temperature on the extraction.

The bifunctional extractant has an increased tendency to form ordered complexes. It follows that there is only a slight decrease in the extraction in the range of practical temperatures ranging from 25 to 600 ° C., as shown in FIG.
R-252 0.1 M dodecane. This fact is an additional advantage of bifunctional extraction agents.

EXAMPLE 14
Regeneration of the extraction agent and uranium.

Removal of the uranium from the charged organic phase takes place by contacting the solvent with H 3 PO 4 of molarity 8 or higher, or with 1M ammonium carbonate.

In a single contact, about 90% of the uranium is recovered with 8M H 3 PO 4, and 78% with the 1M ammonium carbonate. The reagent is then capable of further complexing uranium.

In a typical example, a 0.1 M solution of R-252 in chloroform is contacted with 996 ppm U (VI) in H 2 PO 4 2 M, and the residual uranium is 153 ppm.

The reagent solution is removed and the organic phase is brought back into contact with the same solution of 996 ppm U (VI) in CHCl 3. The residual uranium value is 163 ppm, virtually identical to that of the first experiment.

EXAMPLE 15
Extraction of other metal ions.

In order to establish the interference existing during the extraction between the metal ions (M) and the uranium, the experiments first include the extraction of each isolated ion, then the extraction of the uranium (VI) in the presence of other ions. In all cases, 0.1 M R-252 in dodecane is used. The concentration of ion M, like the concentration of U, is 1000 + 30 ppm. The distribution factors are shown in the table below.

<Tb>

M <SEP><SEP>Factor><SEP><SEP>Factor><SEP> H3PO4 (M) <SEP>
<tb><SEP> Distribution <SEP> Distribution
<tb><SEP> of <SEP> M <SEP> of <SEP> U
<tb> u6 + <SEP> 110 <SEP> 2
<tb> u6 + <SEP> 0.9 <SEP> 8
<tb> Fe3 + <SEP>'<SEP> 4.6 <SEP> 2
<tb><SEP> 0.1 <SEP> 8
<tb> Fe3 + U (VI) <SEP> 2.7 <SEP> 67.2 <SEP> 2
<tb><SEP> 0.04 <SEP> 2.5 <SEP> 8
<tb> Fe2 + <SEP> 0.03 <SEP> 2
<tb> Cu2 ++ U6 + <SEP> O <SEP> 397 <SEP> 2-8
<tb> Cu2 ++ U6 + <SEP> Q <SEP> 4-8 <SEP> 8
<tb> Cd2 + <SEP> 0.02 <SEP> 2-8
<tb> cd2 ++ U6 + <SEP> 0.02 <SEP> 276 <SEP> 2
<tb> cd2 ++ U6 + <SEP> 0.02 <SEP> 3.0 <SEP> B <SEP>
<Tb>

Claims (14)

claims  1. Agent for extraction of heavy metals in ionic form, from their acidic solutions, characterized in that it is in the form of an organic solution of a compound comprising a phosphine oxide group and a phosphoric group or thiophosphoric, bound by a suitable spacer group.  Extraction agent according to claim 1, characterized by the formula

 wherein R 1 and R 2 are each alkyl, cycloalkyl, aryl or substituted aryl, n is an integer of 1 to 20, preferably 1 to 9, m is 1 to 10, preferably> 3 when n is 1, or 1 to 5 when n = 2 Y is oxygen or sulfur, X is oxygen or sulfur, R3 is alkyl, cycloalkyl, aryl, substituted aryl, 4-vinyl benzyl or methylpolystyryl benzyl.  3. Agent according to claim 2, characterized in that the compound is bonded to a hydrocarbon backbone.  4. Agent according to one of claims 2 or 3, characterized in that at least one of the substituents R1, R2 and R3 is a C4 to C12 alkyl group.  5. Agent according to one of claims 2 to 4, characterized in that the R3 group is bonded to a polyvinyl type pendant polymer or to the benzyl group of a polystyrene polymer.  6. extraction agent according to one of claims 2 to 5, characterized in that R1 and R2 are branched alkyl radicals, identical or different, having at least 8 carbon atoms.  7. Extraction agent according to one of claims 2 to 6, characterized in that R3 is an aromatic group which is part of a main aromatic polymer chain, such as polysulfone.  8. extraction agent according to claim 2, in particular for the extraction of uranium, characterized in that the bifunctional compound is 2-ethylhexyl phosphate and dihexyl methylol phosphine oxide.  9. A process for extracting heavy metal ions from acidic solutions, which comprises contacting these ions with a solution of extractants of which at least one is an organophosphoric acid compound, characterized in that another extractant present is a phosphine oxide and the medium contains a small amount of bifunctional extractant according to one of claims 2 to 8, in a proportion of 1 to 20 mol percent of the organophosphoric acid compound, which agent acts as complexing agent, and the metal being recovered by the action of strong acid, in particular phosphoric, hydrochloric, nitric or sulfuric acid, giving a solution of the ion concerned, or which can be precipitated in the form of powder or sponge .  10. Process according to claim 9, characterized in that the bifunctional extraction agent is dihexyl methylol phosphine oxide and 2-ethyl hexyl phosphate.  11. The method of claim 9, characterized in that the uranium, extracted in an organic solvent, is extracted again by contacting an aqueous solution of ammonium carbonate in countercurrent with the organic solvent, in stages, in amount necessary for the neutralization of the organophosphoric acid compound and the conversion of the uranium present in the organic solvent, ammonium tricarbonate and uranyl, and that ammonia is added in the gaseous state or in aqueous solution to the circulating ammonium carbonate solution, in the first step, to maintain the pH in this step at a value of 8 to 8.5.  12. Process according to claim 11, characterized in that the organic solvent, leaving the final stage of the new extraction, is purified by reaction with an acid to remove the ammonium in the form of a salt, and is reused. to a new extraction of uranium.  13. Process according to claim 12, characterized in that the organic solvent, leaving the last stage of the new extraction, is treated with phosphoric acid for the recovery of uranium.  14. New chemical formula

 or R1 and R2 are substituted alkyl, cycloalkyl, aryl or aryl, n is an integer from 1 to 20, more preferably 1 to 9, m is 1 to 10, preferably 1 to 5, Y is O or S, X is O or S, while R3 is alkyl, cycloalkyl, aryl, substituted aryl, 4-vinyl benzyl or benzyl methyl polystyryl.