Cupferron extraction

Cupferron extraction has been applied to the separation of 5-8-minute Ti in neutron activation analysis (l4o), of 3-8-minute V 2 in neutron activation analysis (25,90,132), and of 5-2-minute Cu in neutron activation analysis (132). 

Kooi and Hallatein has used cupferron extractions to concentrate Pu from environmental... 

Cupferron is a ligand whose strong affinity for metal ions makes it useful as a chelating agent in liquid-liquid extractions. The following distribution ratios are known for the extraction of Hg +, Pb +, and Zn + from aqueous solutions to an organic solvent. 

A number of organic compounds, eg, acetylacetone [123-54-6] and cupferron [135-20-6] form compounds with aqueous actinide ions (IV state for reagents mentioned) that can be extracted from aqueous solution by organic solvents (12). The chelate complexes are especially noteworthy and, among these, the ones formed with diketones, such as 3-(2-thiophenoyl)-l,l,l-trifluoroacetone [326-91-0] (C4H2SCOCH2COCF2), are of importance in separation procedures for plutonium. 

Cupferron (ammonium salt of N-nitroso-A -phenylhydroxylamine). The reagent is used in cold aqueous solution (about 6 per cent). Metal cupferrates are soluble in diethyl ether and in chloroform, and so the reagent finds wide application in solvent-extraction separation schemes. Thus Fe(III), Ti, and Cu may be extracted from 1.2 M HC1 solution by chloroform numerous other elements may be extracted largely in acidic solution. 

Procedure. Dissolve a suitable weight of the sample of lead in 6M nitric acid add a little 50 per cent aqueous tartaric acid to clear the solution if antimony or tin is present. Cool, transfer to a separatory funnel, and dilute to about 25 mL. Add concentrated ammonia solution to the point where the slight precipitate will no longer dissolve on shaking, then adjust the pH to 1, using nitric acid or ammonia solution. Add 1 mL freshly prepared 1 per cent cupferron solution, mix, and extract with 5 mL chloroform. Separate the chloroform layer, and repeat the extraction twice with 1 mL portions of cupferron solution + 5 mL of chloroform. Wash the combined chloroform extracts with 5mL of water. Extract the bismuth from the chloroform by shaking with two 10 mL portions of 1M sulphuric acid. Run the sulphuric acid solution into a 25 mL graduated flask. Add 3 drops saturated sulphur dioxide solution and 4 mL of 20 per cent aqueous potassium iodide. Dilute to volume and measure the transmission at 460 nm. 

Molybdenum(VI), vanadium(V), mercury, and iron interfere permanganates, if present, may be removed by boiling with a little ethanol. If the ratio of vanadium to chromium does not exceed 10 1, nearly correct results may be obtained by allowing the solution to stand for 10-15 minutes after the addition of the reagent, since the vanadium-diphenylcarbazide colour fades fairly rapidly. Vanadate can be separated from chromate by adding oxine to the solution and extracting at a pH of about 4 with chloroform chromate remains in the aqueous solution. Vanadium as well as iron can be precipitated in acid solution with cupferron and thus separated from chromium (III). 

Hydroxylamine, IV-benzoyl-lV-phenyl-in gravimetry, 1, 532 liquid-liquid extraction, 1, 544 Hydroxylamine, A -cinnamoyl-A -phenyl-liquid-liquid extraction, 1,544 Hydroxylamine, Ar,A -di-(-butyl-metal complexes, 2, 798 Hydroxylamine, Ay/V-diethyl-metal complexes, 2,798 Hydroxylamine, AAmethyl-metal complexes, 2,798 Hydroxylamine, A -2-naphthol-A -nitroso-ammonium salt — see Ncocupferron Hydroxylamine, A -nilrosophenyl-ammonium salt — see Cupferron Hydroxylamine ligands, 2, 101 Hydroxylamine oxido reductase, 6, 727 Hydroxylases molybdenum, 6,658,662 Hydroxylation arenes... 

Dyrssen, D., Studies on the extraction of metal complexes. IV. The dissociation constants and partition coefficients of 8-quinolinol (oxine) and N-nitroso-N-phenylhydroxylamine (cupferron), Sv. Kern. Tidsks. 64, 213-224 (1952). 

Solvent extraction by tributyl phosphate (TBP) (13, 96), dithizone (20, 71, 72), cupferron (89), thenoyl trifluoroacetone (TTA) (55), diiso-propyl ketone (26), mesityl oxide (92), tri-n-benzylamine and methyl di-n-octylamine (99), diisopropyl and diisobutyl carbinol (100) have all found some application on the trace scale. Acetylaeetone and methyl isobutyl ketone extract milligram amounts of polonium almost quantitatively from hydrochloric acid, but the stable polonium-organic compounds which are formed make it difficult to recover the polonium in a useful form from solutions in these ketones (7). Ion exchange (22, 115, 119) and paper chromatography (44, 87) have also been used for trace scale separations of polonium, but the effects of the intense alpha-radiation on organic com-... 

During precipitation of metal cupferronates from mineral acid solutions, some nitrosophenylhydroxylamine is always coprecipitated. If attempts are made to wash out this water insoluble free acid with an organic solvent or ammonia, some metal is also lost and the remaining precipitate is often hydrolyzed. Consequently, cupferronates cannot be used as final weighing forms, and they serve only for purposes of precipitation and separation. These precipitates often have distinct colours which can form the basis of their estimation after extraction with suitable organic solvents.85... 

Protactinium can be separated from natural ore concentrates by cycles consisting of adsorption on Mn02 precipitates followed by solvent extraction of the cupferron complex with pentyl acetate.94... 

The formation of complex compounds of neptunium with cupferron and a number of other complexing agents has been studied.95 More recently, the extraction of neptunium(IV and VI) from HC1, HBr and HN03 media has been investigated.96... 

Partition behaviour of americium(III) chelates with cupferron and other bidentate reagents was studied spectrophotometrically between a number of inert solvents and dilute HC104 solutions.98 Of special interest may be the data on their extractability and colours of chloroform extracts, collected in a tabular form for cupferronate derivatives of 58 metals. The pH ranges for the formation of cupferronates of 39 metal ions have been shown graphically in this publication.99 Solvent extraction and polarographic techniques were employed to study the possible adducts between technetium and cupferron.100 Evidence indicates a Tcm cupferronate and possibly a pertechnitate adduct, but no indication of a technetium(IV) complex was obtained. 

Very little work has been carried out on cupferron derivatives of main group elements. Some aspects of cupferronates of tin and antimony have been studied122 with a view to developing a suitable method of extraction of the metalloids from a mixture of Sn, Sb, As and Bi. 

It was reported115,1165 that by the use of MIBK or n-BA as diluents, the extraction of thorium by cupferron can be accomplished at a lower pH, which suggests that cupferron and neutral extractants can be good partners for the synergic extraction of thorium. 

Figure 3.22 Adsorptive stripping voltammograms of chromium in groundwater (top) and soil (bottom) samples, using cupferron as a chelating agent. Top curve a, response for electrolyte curve b, same as curve a but after spiking 20 pL of the sample (500-fold dilution) curves c and d, same as curve b, but after additions of 0.1 pg/I. chromium 20 s adsorption. Bottom curve a, response for the electrolyte curve b, same as curve a but after spiking 5 pL of the soil extract (2000-fold dilution) curves c and d, same as curve b but after additions of 0.5 p/L chromium 15 s adsorption. (Reproduced with permission from Ref. 53.)...

SnClf soln. (5 drops). After diluting the aoln. to 50 ml and making pH 5 hy using 1 M NaOH, the V is extracted into an equal volume of O.25 H TTA benzene soln. The V is hack-extracted into 25 ml 6 N HC1 from the benzene soln. After the V (+M-) is oxidized to V(+5) hy 1 M KMnO (5-10 drops), the V is ppted. by 2 ml 6 cupferron aqueous soln. and filtered. Yield - 30. ... 

The HC1 acidic aoln. is diluted to 50 ml with H2O. The V is extracted into 10 ml CHCla hy addition of 2.5 ml 6 cupferron aqueous soln. and 10 ml CHCla. The extract is measured hy 7-spectrometry. Yield = k0. ... 

The V is extracted into 10 ml CHCI3 hy addition of 10 ml 6 cupferron aqueous soln. The extract is measured hy 7-spectrometry. 

After addition of 30 ml cone. HC1 and cooling by pouring on 50-75 ml liquid Nz, the Cu la extracted into 5 ml CCI4 by addition of 10 ml 6 cupferron aqueous aoln. 

The Sn is ppted. by addition of 2 ml 5 cupferron and extracted Into 15 ml ethyl acetate. The organic phase Is washed with 10 ml portions of 1 B HC1. The Sn Is back-extracted Into 10 ml saturated oxalic acid soln. 

To the sample aoln. (10 ml) la added sat. (NHtigCOa and HsO until the yellow ppt., which first forms, dissolves. Sufficient (HH )sCQe -is added to make the final pH of the soln. 8.0-6.5. By addition of 1-2 ml of 6f> aqueous cupferron reagent and 10 ml of CHCle to the above aqueous soln., Th234 Is extracted Into the C CHCI3 layer. The extraction prodedure 1b repeated. 

The combined GHCls extracts are washed with 20 ml of HsO to which has been added 1 ml of cupferron reagent and sufficient (NEiJeCOe soln. to make the pH 8.0-8.5. Then the Th234 Is back-extracted Into 10 ml of 3 M nitric acid containing a few ml of saturated Br2 water which serves to decompose the UXi cupferrate. This allows extraction of all the organic material and excess bromine Into the CHCle phase. 

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