Volume 7 Number 1 March 2022

Kinetics and Mechanism of the Reduction of Tartrazine by Nitrite Ion in Aqueous Acid Phase

Authors: PATRICIA ESE UMORU ; Udoh Ini Effiong
Pages: 10-16
Kinetics and mechanism of the reduction of tartrazine (TZ+) by nitrite ion (NO2-) was conducted in aqueous acidic phase under pseudo-first order condition in excess of [NO2-] at T = 28 ± 1°C, [H+] = 1 × 10-4 mol/dm3, λmax = 560 nm and ionic strength I = 1.0 mol/dm3 (NaCl). The stoichiometry of the reaction displayed 1:2 mole ratio for tartrazine and nitrite ion. The redox reaction was first order with respect to [TZ+] and first order with respect to [NO2-]. A second order rate constant was observed for the reaction. The rate also shows first order dependence on acid ion concentration. The overall reaction conforms to the rate law: [TZ+] = a[H+][TZ+][NO2-] Where a = 6.7343 dm6 mol-2 s-1. The rate of reaction increased with increase in ionic strength. There was no positive polymerization in the reaction. The investigation of spectroscopic and Michaelis- Mentens plot studies did not indicate any complex formation. A plausible mechanism in support of an outer-sphere mechanism is proposed for the reaction.

Synthesis and Spectral Studies of Mixed Ligand Complexes of Trivalent Metal Ions

Authors: F. Y. Larial ; M. M.El-ajaily ; N. M. El-Barasi ; A. A. Maihub ; R. K. Mohapatra ; T. H. Al-Noor
Pages: 1-9
Novel three mixed ligand complexes derived from the interaction of Cr(III), Fe(III) and La(III) ions with a Schiff base resulted from the condensation process of 2-aminophenol and 2-hydroxyacetophenone(HL1) as primary ligand (HL1) and anthranilic acid (L2) as a secondary ligand. The formed mixed ligand complexes were synthesized and characterized using elemental analysis, FTIR, 1HNMR, UV–visible and mass spectroscopy as well as molar conductance and magnetic measurements. The obtained results revealed that the mixed ligand complexes were formed in 1:1:1[L1ML2] ratio and non-electrolytic in nature.