Solvent Extraction Separation of Zirconium (iv) With Anberlite LA - 1 From Citrate Solutions

Abstract

Zirconium was quantitatively extracted with 8 × 10^?2 M of Amberlite LA-1 or LA-2 xylene from 0.001 M citric acid at pH 3.5 and it was stripped from the organic phase with 2 M hydrochloric acid and was determined spectrophotometrically at 665 nm as its complex with arsenazo III. Zirconium was separated from binary as well as tertiary mixtures by exploiting the difference in the distribution coefficient or by selective extraction or selective stripping. The method was applied for the analysis of zircon.

Zirconium was extracted as its anionic complex with various mineral acids by liquid anion exchanger. The chlorocomplex of zirconium was extracted from 6–10 M hydrochloric acid with trioctylamine^1–5, triisooctylamine⁶ or Aliquat 3365⁷. The sulphotocomplex of zirconium was extracted with Aliquat 3365⁸, Primine JMT⁹, Alamine 336¹⁰. The nitratocomplex was less extensively utilised for the extractive separation of zirconium^{11, 12}.

Zirconium was extracted quantitatively from oxalate^{13, 14} and malonate media¹⁵. These extractions were carried out at low pH and separated zirconium from large number of associated elements. The ion exchange chromatographic behaviour of zirconium on column with cation exchange^16–17 or with anion exchange¹⁸ resin with citric acid as eluent were utilised but extraction studies from citrate solutions were never attempted.

From the critical study of existing methods it was observed that zirconium was extracted at narrow pH range; with high concentration of complexing ligand for extraction with liquid anion exchangers and long period of equilibration for extraction as well as stripping. So also such extractions were possible mostly at milligram concentrations involving use of hazardous diluents like benzene. In order to circumvent these difficulties an attempt was made to develop a better method for the solvent extraction separation of zirconium by ion pair formation.

Therefore this paper presents systematic investigations on the solvent extraction separation of zirconium from citrate media with liquid anion exchangers. From the study of various factors. The optimum conditions for the extraction and the separation of zirconium from associated elements are evaluated. The method has been extended for the analysis of zirconium from zircon.     

Liquid-liquid extraction of thorium from malonate solution with liquid anion-exchangers

Thorium is quantitatively extracted with 4% Amberlite LA-1 or LA-2 in xylene, from 0.01M malonic acid medium at pH 3.0 and stripped from the organic phase with 1M hydrochloric acid, then determined spectrophotometrically at 545 nm as its complex with thoron. It is separated from other elements by selective extraction and stripping.     

Liquid/liquid extraction separation of hafnium with amberlite La-1 from zirconium and other elements in citric acid solutions

Hafnium (10–110 μg ml^?1) is quantitatively extracted at pH 4.5 from 0.01 M citric acid with 0.1 M Amberlite LA-1 in xylene; it can be stripped with 0.1 M perchloric acid and determined spectrophotometrically with xylenol orange at 540 nm. Hafnium can be separated from binary and multicomponent mixtures by selective extraction and back-extraction. The method is suitable for determining hafnium in zircon.     

Solvent extraction of scandium from malonic acid with high molecular-weight amines

Scandium is quantitatively extracted with 4% Amberlite LA-1 or Amberlite LA-2 in xylene at pH 2.5-5.5 from 0.1M malonic acid. Scandium is stripped from the organic phase with 0.5M hydrochloric acid and determined spectrophotometrically at 525 nm, as its complex with Alizarin Red S. Primene JM-T, tri-iso-octylamine, tributylamine and tribenzylamine have also been studied as extractants, but found to be unsatisfactory for various reasons. Xylene, toluene, benzene, chloroform, carbon tetrachloride, hexane, cyclohexane and kerosene have been studied as diluents. Xylene is found to be the most efficient. Scandium can be separated from most metals by selective extraction, and from gallium, thallium(III), bismuth, antimony(III), chromium(III), copper(II), iron(III), uranium(VI), cerium, zirconium, indium, thorium and titanium by selective stripping, in some cases combined with use of suitable complexing media to retain the other metals in the organic phase.     

Liquid-liquid extraction of zirconium from hafnium and other elements with dicyclohexyl-18-crown-6

Zirconium was quantitatively extracted with 2.5 × 10^?2 M dicyclohexyl-18-crown-6 in dichloromethane from 8.5 M hydrochloric acid. It was stripped with 0.5 M hydrochloric acid and was determined spectrophotometrically as its complex with Arsenazo III. Hafnium was not extracted under these conditions, but from the residual aqueous phase it was extracted with 7.0 × 10^?2 M dicyclohexyl-18-crown-6 in dichloromethane from 9.0 M hydrochloric acid. It was stripped with 0.1 M perchloric acid and determined spectrophotometrically at 540 nm as its complex with xylenol orange. The separation of zirconium and hafnium from other metals is also described.     

Analytical applications of a liquid anion-exchanger for the separation of uranium(IV) in malonate solution

Uranium was quantitatively extracted with 4% Amberlite LA-1 in xylene at pH 2.5-4.0 from 0.001 M malonic acid. It was stripped from the organic phase with 0.01 M sodium hydroxide and determined spectrophotometrically at 530 nm as its complex with 4-(2-pyridylazo) resorcinol. Of various liquid anion-exchangers tested, Amberlite LA-1 was found to be best. Uranium was separated from alkali and alkaline earth metal ions, thallium(I), iron(II), silver, arsenic(III) and tin(IV) by selective extraction, and from zinc, cadmium, nickel, copper(II), cobalt(II), chromium(III), aluminium, iron(III), lead, bismuth, antimony(III) and yttrium by selective stripping. The separation from scandium, zirconium, thorium and vanadium(V) was done by exploiting differences in the stability of chloro-complexes.     

Solvent extraction separation of hafnium with 4-methyl-3-pentene-2-one

A new method for the extractive separation of hafnium from zirconium is presented. Zirconium is extracted with pure mesityl oxide from 4M nitric acid/4M sodium nitrate medium, followed by extraction of hafnium with mesityl oxide from 0.4M hydrochloric acid/2M ammonium thiocyanate medium. It is possible to accomplish clean separations of Hf from Zr in ratios from 1:20 to 1:200. The separation of hafnium from commonly associated elements such as scandium, yttrium, uranium, thorium, alkali and alkaline earth metals in 500:1 weight ratio to hafnium is also possible.     

Liquid anion-exchange separation of vanadium from malonate media

Summary Vanadium(IV) and (V) can be quantitatively extracted with 0.2 mol/l Amberlite LA-2 in xylene at pH 3.0 from 0.02 mol/l malonic acid, stripped with 0.5 mol/l hydrochloric acid, and determined spectrophotometrically. Five other liquid anion exchangers (Amberlite LA-1, Primene JM-T, Aliquat 336S, TOA and TIOA) were examined as possible extractants. The extraction of vanadium(IV) was found to be quantitative only with Amberlite LA-2, while that of vanadium(V) was quantitative with Amberlite LA-1 and LA-2, Primene JM-T and Aliquat 336S. Eight common solvents were tested as diluents; of these hexane, cyclohexane, benzene, and xylene were found to be satisfactory. Vanadium was separated from elements that do not form anionic complexes with malonic acid by selective extraction, from those that form weak complexes by washing the organic extract with water, and from metals that form strong malonato complexes by selective stripping with hydrochloric, nitric, or sulphuric acid. The method has been applied to the determination of vanadium in steel, coal fly ash and fuel oil. The precision of measurement is within ±5% and the detection limit of the method for vanadium is 0.5 mg/kg.     

Separation of Leucas aspera,a medicinal plant of Bangladesh,guided by prostaglandin inhibitory and antioxidant activities

According to the traditional usage of the plant for antiinflammation and analgesia, Leucas aspera was tested for its prostaglandin (PG) inhibitory and antioxidant activities. The extract showed both activities, i.e., inhibition at 3 x 10(-4) g/ml against PGE(1)- and PGE(2)-induced contractions in guinea pig ileum and a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect. The separation guided by the activities in these dual assay methods provided eight lignans and four flavonoids, LA-1- -12, among which LA-1- -7 and LA-10- -12 were identified as nectandrin B, meso-dihydroguaiaretic acid, macelignan, acacetin, apigenin 7-O-[6"-O-(p-coumaroyl)-beta-D-glucoside], chrysoeriol, apigenin, erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol, myristargenol B, and machilin C, respectively. LA-8 was determined to be (-)-chicanine, the new antipode of the (+) compound, by spectroscopic methods including CD and ORD. Chiral-HPLC analysis of LA-9 showed that it was a mixture of two enantiomers, (7R, 8R)- and (7S, 8S)-licarin A. All of these components were first isolated from L. aspera. PG inhibition was observed in LA-1, LA-2, and LA-5, and antioxidant activity in LA-1- -3 and LA-8- -12.     

Spectrofluorimtric determination of hafnium with 3-hydroxychromone

The fluorescence of the 1:1 hafnium—3-hydroxychromone complex in 4—0.5 M hydrochloric acid is used to determine 0.4—9.0 μg of hafnium in 25 ml of solution; the relative standard deviation is 0.15%. Zirconium does not interfere in 2-fold amounts.     

Olivomycin and related antibiotics XXVIII. Monomeric composition of aureolic acid and proof that the antibiotics LA-7017 and mithramycin are identical to it

Summary 1. It has been shown that aureolic acid, antibiotic LA-7017, and mithramycin are identical.2. It has been established that aureolic acid is a glycoside of chromomycinone (I) and contains the monosaccharides D-olivose (II), D-oliose (III), and D-mycarose (IV) in a ratio of 3 : 1 : 1.For Communication XXVII, see [1], and for a preliminary communication see [2].M. M. Shemyakin Institute of the Chemistry of Natural Compounds, Academy of Sciences of the USSR. All-Union Scientific-Research Institute of Antibiotics. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 537–541, July–August, 1972.     

Liquid-liquid extraction of zirconium with tri-n-butyl-acetohydroxamic acid and spectrophotometric determination in the organic phase with xylenol orange

Zirconium (6–121 μg) is determined with xylenol orange after liquid-liquid extraction by tri-n-butylacetohydroxamic acid (TBAH) from 6 M hydrochloric acid. Under optimal conditions (primarily, 1 1:1.5 ratio of TBAH to xylenol orange, addition of acetic acid, and measurement at 545 nm), the calibration is linear with a molar absorptivity of 34 650 l mol^?1 cm^?1. Ions which are not extracted by TBAH or donot form coloured complexes do not interfere; these include uranium and rare-earth elements. Hafnium interferes; interference from thorium is avoided by a preliminary extraction of zirconium with tri-n-octylamine.     

Reversed phase extraction chromatographic separation of thorium with Amberlite LA-1 from malonate solutions

Thorium was extracted at pH 5.0 from 0.01 M malonic acid on a column of silica gel coated with Amberlite LA-1. Thorium was separated from alkali and alkaline earths, managenese, iron, cobalt, nickel, zinc, tin, in binary mixtures by taking advantage of the difference in the pH of formation of malonato complexes. Thorium was separated from zirconium, uranium, scandium, molybdenum, titanium, by exploiting the difference in the stability of malonato complexes. The method was extended for the analysis of thorium in monazite.     

Einfluss Organischer Lösungsmittel auf die Extraktion von Thorium(IV) und Uran(VI) mit Substituierten Sekundären,Tertiären und Quartären Ammoniumnitraten aus Salpetersauren Lösungen

The influence of methanol on the distribution of thorium(IV) and uranium(VI) between aqueous solutions of nitric acid and solutions of Amberlite LA-2, trilaurylamine and Aliquat-336-nitrate has been investigated. The amount of acid in the organic phase increases with increasing concentration of nitric acid and methanol in the aqueous phase. The concentration of acid in the organic phase can be calculated by a given formula for Amberlite LA-2. The distribution of methanol is discussed. The distribution of thorium(IV) and uranium(VI) changes, when methanol is added. This is explained by the shift of the equilibrium of the metal complex and by the enhanced extraction of acid.     

Radiochemical separation of zirconium and hafnium from other radionuclides

Radiozirconium and radiohafnium may be separated from all other radionuclides except scandium and protactinium by precipitation with mandelic acid from 5-10 M hydrochloric acid, using commercial zirconyl chloride as carrier. Scandium and protactinium are removed by dissolving the precipitate in sodium carbonate, then adding barium nitrate to precipitate barium carbonate which acts as a scavenger. Zirconium mandelate is finally reprecipitated and the sample weighed and counted in this form. The method was checked by analysing commercial zirconyl chloride and standard rock samples for zirconium and hafnium by neutron-activation analysis.     

Einfluss Organischer Lösungsmittel auf die Extraktion von Thorium(IV) und Uran(VI) mit Substituierten Sekundären,Tertiären und Quartären Ammoniumnitraten aus Salpetersauren Lösungen

The influence of ethanol on the distribution of thorium(IV) and uranium(VI) between solutions of nitric acid and solutions of Amberlite LA-2, Trilaurylamine and Aliquat 336-nitrate has been investigated. Increasing amounts of nitric acid and ethanol in the aqueous phase cause an increase of the acid concentration in the organic phase. This concentration can be calculated by a given formula for Amberlite LA-2. The distribution of acid and ethanol is discussed. The distribution ratios of thorium(IV) and uranium(VI) are changed by adding ethanol to the liquid-liquid-system. This can be explained by the shift of the equilibrium of the metal nitrate complexes and by the enhanced extraction of acid.      

Separation of zirconium by thin-layer chromatography

The thin-layer Chromatographie separation of a number of metal ions [Sc, Y, Zr, La, Sm, Th, U(VI), etc.] with solvent mixtures of mesityl oxide, ethanol and 5M nitric acid on silica gel-cellulose (5:1) thin-layer plates is reported. Zirconium remains stationary whilst the other metal ions move with the solvent, thus allowing a selective separation of zirconium from about 20 metal ions in ratios ranging from 100:1 to 1:100. Mixtures of various metal ions can also be separated.     

Reversed Phase Extraction Chromatographic Separation Of Scandium With Amberlite LA-1 From Malonate Solutions

Abstract

Scandium was extracted at pH 5.0 from 0.01 M malonic acid on silica gel column impregnated with Amberlite LA-1. Nickel, zinc, cadmium, mercury, lead, tin, aluminium, and lanthanum in binary mixtures because they could not form malonato complexes. It was separated by the process of selective elution from elements such as zirconium, thorium, uranium, iron(III), gallium, indium, cerium(III), litanium by exploiting difference in stability of malonato complexes. Scandium was separated from multicomponent mixture containing yttrium, titanium, zironium, thorium, uranium and aluminium by a process of selective sorbtion and selective elution.     

Die Verteilung von Uran(IV) zwischen wässriger Salpetersäure und organischen Lösungen des Nitratsalzes des sekundären Amins Amberlite LA-1

The nitrate salt solution of the secondary amine Amberlite LA-1 in organic solvents extracts uranium(IV) from aqueous nitric acid solutions. The distribution ratio of uranium(IV) reaches a maximum at an equilibrium nitric acid concentration of 8.5M in the aqueous phase. Addition of n-octanol to the organic phase decreases, and the addition of nitrate to the aqueous phase increases the uranium(IV) distribution ratio. The extraction of uranium(IV) is fast and the equilibrium distribution is reached within less than one minute. At low uranium(IV) concentrations (<6·10⁻³ M) the distribution ratio is independent of the uranium(IV) concentration. At high uranium(IV) loadings of the organic phase an extrapolation gives a mole ratio of amine: uranium(IV)=2∶1. A double logarithmic plot of the dependence of the uranium(IV) distribution ratio vs. the LA-1 concentration in the organic phase gives a curve with a slope of two when polar diluents for LA-1 are used. This slope of two and the shapes of the absorption spectra of the organic phase from 400 to 700 nm make it very probable that uranium(IV) exists in the organic phase as a hexanitrato complex.      

über die Abtrennung geringer Mengen Zinn aus hochreinem Nickel mit Amberlite LA-2 und deren Bestimmung mit Phenylfluoron

Traces of tin can be separated from large amounts of nickel by extraction with a solution of Amberlite LA-2 in xylene. After back-extraction into diluted nitric acid tin is determined spectrophotometrically using phenylfluorone as reagent. The method is suitable for the determination of low tin contents in nickel of high purity.