Emprego de acidos hidroxamicos na extração dos ions Co (II), Cu (II), Fe (III), Ti (IV) e V(V) por solventes organicos e sua determinação por espectrofotometria de absorção atomica e na região do UV - visivel

AUTOR(ES)

Francisco das Chagas Ferreira Clementino

DATA DE PUBLICAÇÃO

1987

RESUMO

For this project four hydroxamic acids were synthesized, two being derivatives of phenylcinnamohydroxamic acid and two of phenylbenzohydroxalllic acid. N-benzoyl-p-tolylhydroxylamine was used for the extraction and separation of Copper (lI) and Iron (lII) in toluene, in the pH ranges of 7.0 to 10.0 and 1.0 to 6.0, respectively. The copper extracted with this hydroxamic acid was determined by atomic absorption spectrophotometry, after adding ethanol (to 10% of the volume) to the organic solution. Since iron complexed with N-benzoyl-p-tolylhydroxilamine is colored red-orange, with a molar absorptivity of 5.2 x 10 at 440 um. it was determined by visible spectrophotometry. The concentration t.ange for the determination of iron is 2 to 10 mgFe/ml according to its Ringbonl curve. This method was used to determine Fe(III) in cement and limestone. N-cinnamoyl-o-tolylhydroxylamine was used for the extraction and separation of cobalt (ll) and titanium (IV) in toluene. The quantitative ex- tration of cobalt recurs between pH 8.5 and 9.5. The complex was determined by its ultraviolet absorption. Both binary and ternary systems were studied with titanium, obtaing quantitative extraction in 8 to 11M HCl with binary systems and between 10and 11 M HCl with the ternary systems . Both complexes were determined spectrophotometrically at 390 nm, the molar absortiovities being 1.50 x 10 and 3,07 x 10 l.mol.cm, respectively. N-cinnamoyl-o-tolylhydroxilamine was also used for the extraction of vanadium (V) in binary and ternary systems. These complexes were extracted between10 and 5 M em HCl and determined at 510 and 570 nm, respectively, with molar absortivities of 6,4 x 10 and 7,6 x 10 l.mol.cm. Ringbom curves indicate the concentration range as 2.0 to 7.0 mgV(V)/ml with sensitivities (according to sandell s deffenition) of 0.008 mgV(V)/cm and 0.007 mgV(V)/cm respectively. Interferences were determined for the binary systems fo Co(II), Fe(lll), Ti(IV) and V(V).

ASSUNTO(S)

acidos hidroxamicos espectrofotometria

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