Naslov
Extraction and Formation of Iron(III) Thiocyanate Comoplexes: Application for Spectrophotometric Determination of Iron

Autori
Gojmerac Ivšić, Astrid ; Tamhina, Biserka

Izvornik
Croatica Chemica Acta (0011-1643) 76 (2003), 2; 323-328

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
extraction; iron; spectrophotometry; thiocyanate

Sažetak
Extraction of iron(III) from sulphuric and hydrochloric acid solutions containing an excess of thiocyanate ions with tetraphenylphosphonium (TPP) chloride and cetyltrimethylammonium (CTMA) bromide in chloroform was investigated. The optimum conditions for extraction by both extractants were determined. The extraction behaviour of CTMA was found to be more efficacious than that of TPP because less of thiocyanate and extractant was required. Better extraction efficiency of CTMA can be atributed to surfactant active properties of this substance. The formation of an extractable iron(III) thiocyanate complex with CTMA or TPP was also determined spectrophotometrically by measuring the absorbance of the organic phase at 473 nm or 506 nm respectively. The composition of the extracted iron(III) complexes were determined by distribution and spectrophotometric methods. The molar ratio Fe:SCN:TPP of the extracted complex was 1:4:1 ; accordingly, its composition was [TPP] [Fe(SCN)4]. The molar ratio Fe:CTMA of the extracted complex was 1:3. The molar ratio Fe:SCN in the complex extracted with CTMA was not possible to determine because of the turbidity in solutions containing less than 0.01 mol dm3 thiocyanate ion, but it can be concluded that the composition of extracted complex was [CTMA]3 [Fe(SCN)6].

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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