G. Mariappani, B. P. Sala, N. R. Bhuyan, P. R. Bharti and K. Deepak, “Evaluation of Antioxidant Potential of Pyrazolone Derivatives,” Journal of Advanced Pharmaceutical Technology & Research, Vol. 1, No. 2, 2010, pp. 260- 267.

has been cited by the following article:

• TITLE: Studies on Extraction Behaviour of Cobalt(II) with Nitrobenzoylprazolone-5

  AUTHORS: Onyedika Gerald, Arinze Judith, Ogwuegbu Martin

  KEYWORDS: Extraction; Solvent; Complex; Pyrazolones

  JOURNAL NAME: Journal of Minerals and Materials Characterization and Engineering, Vol.1 No.3, May 24, 2013

  ABSTRACT: The extraction of Cobalt(II) from aqueous solution using 1-phenyl-3-methyl-4-(p-nitrobenzoyl)pyrazolone (HPMNP) in various organic solvents was studied as a function of pH and extractant concentration. Extraction into organic chloroform phase was more efficient than with any other solvent. The extraction equilibrium constant was found to be log Kex= -7.04. Optimum conditions for extraction of Co(II) exist at pH of between 5.5 and 7.0, ionic strength of 0.3 Mand constant extractant concentration of 0.02 M. Shaking the organic Co(II) chelate complex with 0.2 Macid strips the Co(II) ions into the aqueous phase. It was established that Co(II) complex extracted is of composition, Co(PMNP)2.