Kinetic studies on the solvent extraction of iron(m) from aqueous solution with I-phenyl- 3-methyl-4- (p-nitrobenzoyl)pyrazol- 5-one dissolved in chloroform: Rate of forward extraction

Abstract

The rate of forward extraction of iron(III) from aqueous solution using 1-phenyl- 3-methyl-4-(<em>p</em>-nitrobenzoyl)pyrazol-5-one, HNP in chloroform has been investigated at various conditions. Experimental observation shows that the rate of forward extraction is first order each with respect to [Fe(III)] and [HNP]_org, and inverse first order with respect to [H⁺]. The rate of forward extraction of Fe(III) is proposed to be controlled by the formation of the first complex between Fe(H₂O)<img src='http://www.niscair.res.in/jinfo/equation142.gif' border=0> or Fe(H₂O)₅OH²⁺ and the extractant anion, NP^-. The rate constant, <em>K</em>_ffor the forward extraction and the extraction equilibrium constant, K_ex have been determined respectively as 5.83 x 10²s^-¹ and 0.18.