Trioctylphosphine oxide extractant

El-Reefy, S.A., Selim, Y.T., and Aly, H.F., Equilihrium and kinetic studies on the separation of uranium and thorium from nitric acid medium by liquid emulsion membrane based on trioctylphosphine oxide extractant. Anal. Sci., 1997, 13 333-338. 

The application of liquid emulsion membrane based on trioctylphosphine oxide extractant for the separation of thorium and uranium was described [3]. Thoron I was used to determine Th in aqueous phase. 

A liquid emulsion membrane based on trioctylphosphine oxide extractant was applied for separation of uranium and thorium from Ce, Cu and Cd [2]. Highly selective U02 imprinted polymer (synthesized using uranium vinylbenzoate, divinylbenzene in styrene and 2,2 -azobisisobutyronitrile) was proposed for purification, preconcentration and determination of the uranyl ion [3]. Dibenzoylmethane was used as a colorimetric reagent. The detection limit of 160 ppt was achieved. 

The study of frozen aqueous solutions of iron(III) compounds is only of limited value because of the tendency to hydrolyse, and the relaxation broadening [63, 128], and little work has been done. A potentially more profitable application is the study of solvent extracts. Frozen nitrobenzene extracts of iron(III) in HCl, HBr, and NaSCN solutions contain respectively the FeCl4 and FeBr4 anions and a 6-coordinate complex Fe(NCS)4X2 (X is either water or nitrobenzene) [129, 130]. The spin-spin relaxation behaviour is dependent on the solvent, and trioctylphosphine oxide extracts show partially resolved hyperfine structure. 

Tetrahydrofuran Trihexylphosphine oxide extraction agent, acetic acid recovery Trioctylphosphine oxide extraction agent, actinide Aluminum nitrate nonahydrate extraction agent, animal/vegetable oils Methyl alcohol... 

The O or S atoms in P=0 and P=S groups may act as electron donors although these groups form relatively weak complexes with electron acceptor compounds such as nonpolarizable, more electropositive (ie, hard) acids, including protons (14). Use is made of this property in the recovery of uranium from wet-process phosphoric acid by extractants such as trioctylphosphine oxide [78-50-2] and di(2-ethylhexyl) hydrogen phosphate [298-07-7]. 

Inoue, K. Nagamatsu, I. Baba, Y. Yoshizuka, K. Solvent extraction of platinum(TV) by trioctylphosphine oxide. Solvent Extr. Ion Exch. 1989, 7, 1111-1119. 

Hasegawa, Y. Kobayashi, I. Okuda, A. Solvent-extraction behavior of platinum(TV) and palladium(II) as chlorocomplex acids with trioctylphosphine oxide. Anal. Sci. 1991, 7, 377-381. 

Korkisch and Koch [106,107] determined low concentrations of uranium in seawater by extraction and ion exchange in a solvent system containing trioctyl phosphine oxide. Uranium is extracted from the sample solution (adjusted to be 1 M in hydrochloric acid and to contain 0.5% of ascorbic acid) with 0.1 M trioctylphos-phine oxide in ethyl ether. The extract is treated with sufficient 2-methoxyethanol and 12 M hydrochloric acid to make the solvent composition 2-methoxyethanol-0.1 M ethereal trioctylphosphine acid-12 M hydrochloric acid (9 10 1) this solution is applied to a column of Dowex 1-X8 resin (Cl" form). Excess of trioctylphosphine oxide is removed by washing the column with the same solvent mixture. Molybdenum is removed by elution with 2-methoxyethanol-30% aqueous hydrogen peroxide-12 M hydrochloric... 

DEPA-TOPO [di (2-ethylhexyl) phosphoric acid and trioctylphosphine oxide] A process for recovering uranium from wet-process phosphoric acid, by solvent extraction with a mixture of the two named reagents. Developed at Oak Ridge National Laboratory and first commercialized in 1978 by Freeport Minerals Corporation and Wyoming Mineral Corporation. 

Ramadan, A., Mahmoud, M., Khalifa, S.M., Souka, N. Extraction of Eu(III) by dinonyl-naphthalenesulfonic acid and synergistic effects of crown ethers and trioctylphosphine oxide. J. Radioanal. Nucl. Chem. (1993), 176 (6), 457 170. 

Moreover, under a particular set of conditions, the extraction efficiencies for the SC-C02 system were typically found to be very similar to the corresponding values in dodecane. The strong correlation between the SFE and conventional SX results for the two ions suggests that the solvation behavior of SC-C02 is similar to that of dodecane for the TBP system. Substitution of a stronger Lewis base, such as triph-enyl- (TPPO), tributyl- (TBPO), or trioctylphosphine oxide (TOPO) for TBP, generally yielded higher extraction efficiencies for both uranium and thorium. For both TBPO and TOPO, in fact, extraction was nearly quantitative over the entire range of... 

This behavior has allowed the development of solvent-extraction procedures for alkali metal ions. Thus not only can the trioctylphosphine oxide adduct in Li[PhC(0)CHC(0)Ph][OP(octyl)3]2 be extracted from aqueous solutions into p-xylene, but this process can also be used to separate lithium from other alkali metal ions. Even Cs+ can be extracted from aqueous solutions by l,l,l-trifluoro-3-(2 thenoyl) acetone (TTA) in MeN02—hydrocarbons, and all of the M+ ions can be extracted into chloroform by crown ethers, in a manner that depends upon the associated anions.33... 

A number of investigations on the synergistic effect of a second extractant, such as amines and oximes, on the extraction of metal carboxylates have been carried out. The utilized synergists include 8-hydroxyquinoline-2-aldoxime for Zr(IV) and Hf(IV) (122,123), various amines (25), Lix 63 (27) and nonylphenol (28) for Cu(II), dialkylphos-phoric acids for Hf(IV) (44), rhodamine B for Be(IE) (102), trioctylphos-phine oxide for U(VI) (69, 77), p-alkylphenol for Cs(I) (1), collidine for Zr(IV) and Sc(IEI) (62), and nonchelating oximes for Ni(II) and Co(II) (103). Mareva et al. (77) have successfully utilized a salicylic acid-trioctylphosphine oxide mixture for the separation of uranium from rare earths, thorium, zirconium, and iron. 

Phosphate rock and phosphoric acid Wet digestion separation by extraction with trioctylphosphine oxide destruction of complex prior to analysis Argon plasma emission spectrometry No data 98-100 Woodis et al. 1980 ... 

Phosphate rock Wet digestion extraction with trioctylphosphine oxide back-extraction with stripping solution dc argon ICP <1 ppm 99-106 Norman et al. 1983... 

A water-soluble sulfonated crown ether (see Figure 80) has been prepared and used as an ion size selection reagent. In the synergistic extraction of alkaline earth ions with 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone and trioctylphosphine oxide in cyclohexane, addition of the sulfonated crown ether shifted the extraction for the larger ions to a higher pH level, thereby improving the... 

As a comparison, the extraction of Th from xylene by trioctylphosphine oxide (TOPO), Cyanex 921 (similarly available through Cytec Inc.) (Table 19), has also been studied and extractant dependency indicates a 1 2 metahextractant complex ratio like that seen for TRPO. 

Commercially available Cyanex 923, or TRPO (see Table 19), has been used for the successful extraction of ions from nitric acid solutions into xylene. Extractant dependency gives a slope of two for hexavalent uranium, similar to the behavior observed for trioctylphosphine oxide... 

Slope analyses to determine the extraction stoichiometries of Am for both the CeHs and CIC6H4 extractants were performed to determine pH, TBP, and extractant dependencies. For Am , many nonintegral slopes were obtained, indicating that mixed complexes with varying stoichiometries are being extracted. It is believed that the extractants may act similarly to Cyanex 301 and form complexes of the type AmA3(HA) cTBP, but the values for x and y are still undetermined and further work needs to be done. Trioctylphosphine oxide was found to be the best synergist for Am extraction. 

Trioctylphosphine oxide (TOPO) is an organophos-phorus compound and is a stable and inexpensive extractant. TOPO, as we have shown [3-5], is unique in that it can function as a monodentate ligand and as a cation for ion-pair extraction when protonated and the extraction equilibrium for the neutral ligand is shown in Eq. (5), indicating the extraction of the neutral complex MCl2(TOPO)2 [M = Pd(II), Pt(II) n = 2-4] ... 

In the reduction stripping process uranium(IV) in the raw wet process acid is oxidized to uranium(Vl) by treatment with sodium chlorate, hydrogen peroxide or air at 60 to 70°C, the uranium(VI) formed being extracted with trioctylphosphine oxide/di-(2-ethylhexyl)phosphate in kerosene and the resulting solution finally reductively stripped repeatedly with aqueous iron(II) solutions. This results in an enrichment by a factor of 40. After oxidation of the stripped solution with sodium chlorate or ambient oxygen and renewed extraction of the uranium(VI) formed with trioctylphosphine oxide/di-(2-ethylhexyl)phosphate, the phosphoric acid is removed from the organic phase by washing. The uranium(Vl) is then stripped with ammonium carbonate and precipitated as the ammonium diuranyl-tricarbonato-complex. This is filtered off, washed and calcined. 

In the oxidation stripping process the uranium(VI) in the raw wet process acid is initially reduced to uranium(IV), which is extracted with a mixture of mono and dioctylphenyl esters of phosphoric acid in kerosene. Oxidation with sodium chlorate in phosphoric acid transfers the uranium to the aqueous phase and it is then extracted with trioctylphosphine oxide/di-(2-ethyIhexyl)-phosphate, as in the reduction stripping process. 

The phosphine oxide most commonly used as an extractant is trioctylphosphine oxide (TOPO). The order of extraction of U(VI) from mineral acid by TOPO is HNO3 > HC1 > HCIO4 (27). Extensive... 

Many of the early reports of complexes with bidentate oxygen ligands involved acac complexes and the /3-diketonate and related ligands were discussed in CCC (1987).210 The /3-diketonate complexes of scandium and yttrium and the lanthanides were also discussed in CCC (1987).1 Many reported systems contained adducts formed by the metal /3-diketonate complexes. In solution some of the complexes with bidentate ligands can expand their coordination number to seven by coordination to a suitable donor ligand. A solvent extraction method has been used to show that Sc(acac)3 does not form an adduct with trioctylphosphine oxide but tris(tropolonato)scandium(III) and tris-(ethylmatolato)scandium(III) do coordinate with trioctylphosphine oxide.211... 

Calcium, Sr, and Ba can be extracted as crown-ether complexes [10,11], which enable one to separate those elements [12,13]. Ca (and Sr) was also extracted with pyrazolone derivatives and with trioctylphosphine oxide (cyclohexane) [14]. Calcium can be extracted with Cryptand 2.2.2 using Erythrosin as the counter-anion [14a]. 

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