Yasumasa Shigetomi

Extraction of gold, silver, mercury, platinum(II) and palladium with O,O′-diisopropyl-S-benzylthiophosphate into molten diphenyl

Abstract Liquid-liquid distribution with O,O ′-diisopropyl- S -bebzylthiophosphate (DPBTP), tri-n-octylphosphine oxide, tri-n-butylphosphate, di-n-hexylsulfide (DHS) and O,O ′-dimethyl- O -(3-methyl-4-nitrophenyl)triophosphate (DMTP) into molten diphenyl was investigated for the extraction of metals from hydrochloric, nitric and sulfuric acid solution. Silver(I), gold(III), mercury(II), platinum(II) and palladium(II) can be selectively extracted with DPBTP, DHS and DMTP.

Separation and spectrophotometric determination of uranium(VI) by extraction with tri-n-octylphosphine oxide and benzophenone

Uranium(VI) is separated by extraction from nitric acid medium into a molten mixture of tri-n-octylphosphine oxide and benzophenone at about 50 degrees . The organic phase solidifies on cooling and is separated and dissolved in ethanol. The uranium(VI) in this solution is then determined spectrophotometrically with 1-(2-pyridylazo)-2-naphthol.

Spectrophotometric determination of uranium(VI) in phosphoric acid by means of solvent extraction with mixtures of TOPO and biphenyl

The variations in the distribution coefficients of twelve metals and uranium between nitric acid or hydrochloric acid-TOPO (trioctylphosphine oxide) systems have been studied as functions of the concentration of nitric acid, hydrochloric acid and TOPO and temperature (in the range 70–80 °C), employing biphenyl as the diluent for TOPO. The formula UO2(NO3)2-(TOPO)2 can be assigned to the complex. Uranium in a phosphoric acid solution is quantitatively extracted from 2 mol dm–3 nitric acid into molten TOPO-biphenyl at about 70 °C. The organic phase separates out as a solid on cooling and is dissolved in ethanol. The uranium in this solution is then determined spectrophotometrically with 1-(2-pyridylazo)naphth-2-ol. Beers law holds in the range 1–8 p.p.m. of uranium, and the relative standard deviation for 10 determinations was 2.1%.

Separation of uranium(vi) by liquid-solid extraction with tri-n-octylphosphine oxide diluted with naphthalene

Abstract Liquid-liquid distribution with tri-n-octylphosphine oxide (TOPO)and molten naphthalene has been investigated for the extraction of 20 metals from nitric acid and hydrochloric acid solutions. Uranium is quantitatively extracted from 1 M nitric acid or hydrochloric acid by using 100 mg of TOPO and 200 mg of naphthalene and shaking for 5 min at 80°C, and separated from transition metals, alkaline earth metals and rare earth metals (except scandium). Addition of naphthalene increases the extraction efficiency.

Adsorption behaviour and separation of copper(II) ions on cellulose triacetate polymer containing α-hydroxy oxime compounds

Abstract A series of α-hydroxy oxime compounds was synthesized and characterized. A new type of adsorbent, cellulose triacetate (TAC) powder (20–60 mesh) containing five kinds of α-oxime compounds such as α-benzoin oxime and 2-hydroxyphenyl ethyl ketone oxime (HPEKO), was prepared by dissolving cellulose triacetate with α-oxime in dichloromethane and pouring the mixture into hot water. The adsorption behaviour with α-oxime—TAC powders was examined for seven metal ions from solution of pH 2–10. Copper(II) was quantitatively retained on the HPEKO—TAC in the pH range 4–10 in batch experiments, whereas negligible adsorption was obtained for cobalt(II), iron(III) and iron(II); palladium(II) was also quantitatively adsorbed. The retention capacity of copper(II) and nickel(II) on the loaded adsorbent was about 1.4 and 1.1 mg g −1 at pH 5.9 and 8.1, respectively. Copper(II) retained on the column was completely eluted with 50 cm 3 of 0.25 mol dm −3 hydrochloric acid, and separated from nickel(II) and iron(III).

Extraction of complexes of iron(III) and other metals with bis(2-ethylhexyl)phosphoric acid into molten biphenyl/naphthalene

Abstract The extraction behaviour of twelve metals as function of the concentration of nitric or hydrochloric acid is described; bis(2-ethylhexyl)phosphoric acid (BEHPA) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester are used as the extractants with 3:1 (w/w) biphenyl/ naphthalene (m.p. 52°C) as the molten solvent which is easily separated by cooling to room temperature. Scandium (III) and zirconium (IV) can be separated from uranium (VI), rare earth metals and some transition metals with BEHPA. The extraction behaviour of iron with both extractants is described in detail.

Reducing elution method for copper(II) in cation-exchange chromatography by hydroxylamine hydrocloride solution

The cation-exchange Chromatographic behaviour of copper and several other metals in hydroxylamine hydrochloride solution has been investigated. At 50 degrees copper(II) is reduced to copper(I) which is eluted quickly in a narrow band and easily separated from other metals such as zinc, nickel, cobalt and iron.

Spectrophotometric determination of uranium(VI) by solvent extraction with trioctylphosphine oxide and a molten mixture of biphenyl and naphthalene

Uranium in ores has been determined spectrophotometrically after extraction with trioctylphosphine oxide (TOPO) into a molten mixture of biphenyl and naphthalene. By addition of salting-out agents such as sodium nitrate to the aqueous phase and cooling, the organic phase can be obtained as a solid lump on the surface of the aqueous phase, making its collection simple. The uranium can then be determined directly in the organic phase with 1-(2-pyridylazo)-2-naphthol or 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol.

Electron-transfer induced rearrangement of thiocyanate to isothiocyanate

Benzyl thiocyanates with an electron-withdrawing group (1a, 1b) and 9-fluorenyl thiocyanate (1e) rearrange to the corresponding isothiocyanate (2) under 9,10-diphenylanthracene (DPA) sensitization. The rearrangement would proceed via carbon–sulfur bond cleavage in an anion radical of 1 produced by photoinduced electron transfer, followed by back electron transfer to DPA·+ and recombination of the resulting radical or ion pair.

Sulfate ion selective electrode based on poly(vinyl chloride) membrane containing barium chloranilate.

A solid membrane electrode selective to sulfate ion was prepared from barium chloranilate (CLB) with poly(vinyl chloride) (PVC). The electrode exhibited sub-Nernstian response within the sulfate ion concentration range 10 -110 -4 mol dm -3 at pH range of 47. The membrane electrode showed good selectivity to sulfur ion and was applied to determine sulfur in polymer and sulfate ion in seawater.