Phosphonate extraction

Separation of Transuranium Elements by Phosphonate Extraction. Trans. 

In the extraction studies, to be reported elsewhere, involving the use of monoacidic phosphonate extractants of the (GO)(C1CH2)P0(0H) type (where G represents phenyl groups with various substituents) with essentially constant acidities but with varying amounts of steric hindrance within the extractant molecule, the range of Kg values was 2.6 x 107 for Th(IV) and 22 for U(VI). Thus, steric hindrance within the extractant molecule was established as a very important factor in LLE sepa-rat ions. 

In Figure 5, P, C, and A1 CP-MAS spectra obtained after 2 weeks for 26 wt % GB reacted with as received AP-AI2O3 are shown along with P MAS and "C and A1 CP-MAS NMR spectra of 1. In the P CP-MAS NMR spectra of GB/AP-AI2O3, two broad peaks are observed at 22.5 and 14.4 ppm which possess intense spinning side bands, indicative of two distinct, immobilized phosphonates. Extraction of the surftice species and analysis by P... 

Cao, X., Yin, M., and Li, B. (1999). Determination of rare earth impurities in high purity gadolinium oxide by inductively coupled plasma mass spectrometry after 2-ethylhexyl-hydrogen-ethylhexy phosphonate extraction chromatographic separation. Talanta 48(3), 517. 

Neutral Extractants. Many neutral organophosphoms extractants are available phosphate esters, phosphonate esters, phosphinate esters, and phosphine oxides. The most popular neutral extractant is tributylphosphate (TBP), which reacts with RE elements according to a solvation mechanism ... 

M HNO3) and from 3 M HNO3 using dilute solutions of DHDECMP, HHDECMP, 0(j)D[IB]CMP0 in o-xylene showed that the increase in D/ in the series phosphone-phosphinate-phosphine oxide was due primarily to an increase in the enthalpy of extraction. 

This paper describes a comparison of the extraction behavior of selected. actinide(III), (IV), and (VI) ions by the dihexyl-N, N-diethyl analogs of carbamoylmethyl-phosphonate and phosphinate and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide. 

Extractants derived from the carbamoylmethylphosphoryl moiety (CMP) were studied in the phosphonate, phosphinate, and phosphine oxide classes. Our studies focused on dihexyl-N,N-diethylcarba-moylmethylphosphonate, DHDECMP, hexyl hexyl-N,N-diethylcarbamoyl-methylphosphinate, HHDECMP, and octyl(phenyl)-N,N-diisobutylcarba-moylmethylphosphine oxide, 0D[ IB]CMP0. The three types of CMP extractants were compared on the basis of nitric acid and extractant dependencies for Am(III), solubility of complexes on loading with Nd(III) and U(VI), and selectivity over fission products. On the basis of the above data two conceptual flowsheets were developed. The first flowsheet involves the extraction of all of the actinides from HLLW using 0.4 M 0D[IB]CMP0 in DEB. The second flowsheet involves the extraction of all of the actinides from dissolved spent LWR fuel using 0.8 M DHDECMP in DEB. 

Another GC/MS method that was validated as a food tolerance method involved the determination of glyphosate and (aminomethyl)phosphonic acid (AMPA) in crops. In this method, glyphosate and AMPA residues are extracted from crop commodities (corn grain) with water. The extracts are then partitioned with dichloromethane,... 

This technique has been used to study the extraction kinetics of rare-earth elements from an aqueous phase into heptane by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEH/EHP) [31]. The linear dependence of f c ) on t in Fig. 5 was considered to indicate that the extraction of ErCl3 by HEH/EHP is a diffusion-controlled process. 

The use or safe disposal of the iron residues from zinc production (see Figure 7) presents a major technical problem.204 The use of chelating aminomethylene phosphonic acid extractants such as (28) and (29) to recover iron from these residues has been proposed.205 These give much higher FenI/Znn selectivity than D2EHPA but are more difficult to strip. A reductive-stripping process is proposed.187,205... 

Jayachandran, J. Dhadke, P. M. Solvent extraction separation of cobalt(II) with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A). Chem. Anal. 1999, 44, 157-165. 

Preston, J. S. Solvent extraction of cobalt and nickel by organophosphorus acids. I. Comparison of phosphoric, phosphonic, and phosphinic acid systems. Hydrometallurgy 1982, 9, 115-133. 

Butyllithium (23% in hexane) (63 ml, 0.15 mol) was added dropwise to diethyl phosphite (25 g, 0.18 mol) at -20 to -30°C over a period of 2 h. To the resulting mixture was added A/-methoxy pyridinium meth-osulfate in dimethyl phosphite (40 ml) over a period of 1 h at -15°C. The reaction mixture was stirred at room temperature overnight, and water (100 ml) was then added. The mixture was extracted with chloroform (3 x 75 ml), and the combined organic extracts were separated into neutral and basic fractions by extraction (4 N HC1), bas-ification, and reextraction with chloroform. The basic portion was distilled yielding diethyl pyridine-2-phosphonate (22.9 g, 67%) of boiling point (bp) 105-112°C/0.08 torr. 

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