Kinetics and Mechanism of Oxidation of Triethylene Glycol and Tetraethylene Glycol by Ditelluratoargentate (III) in Alkaline Medium

Jinhuan Shan,Caihong Yin

doi:10.1155/2013/793560

Abstract

The kinetics of oxidation of triethylene glycol and tetraethylene glycol by ditelluratoargentate (III) (DTA) in alkaline liquids has been studied spectrophotometrically in the temperature range of 293.2 K–313.2 K. The reaction rate showed first-order dependence in DTA and fractional order with respect to triethylene glycol or tetraethylene glycol. It was found that the pseudo-first-order rate constant(kobs)increased with an increase in concentration of OH−and a decrease in concentration ofH4TeO6 2−. There was a negative salt effect and no free radicals were detected. A plausible mechanism involving a two-electron transfer was proposed, and the rate equations derived from the mechanism explained all the experimental results and observations. The activation parameters along with the rate constants of the rate-determining step were calculated.

Highlights

Many researchers from many countries are interested in the study of the highest oxidation state of transition metals which in a higher oxidation state generally can be stabilized by chelation with suitable polydentate ligands. Metal chelates, such as diperiodatoargentate (III) [1], ditelluratoargentate (III) [2], ditelluratocuprate (III) [3], and diperiodatonickelate (IV) [4], are good oxidants in a medium with an appropriate pH. e oxidation of a number of organic compounds and metals in lower oxidation state by Ag(III) has been performed [5, 6]. e research is focus on the kinetics of oxidation of small molecules by DTA
The mechanism of the oxidation of triethylene glycol and tetraethylene glycol by DTA is reported. Both of triethylene glycol and tetraethylene glycol which serve as thinners, solvent, and dispersant, are used in coatings, inks, printing, dyeing, pesticide, cellulose and acrylic acid industry, and so forth
Under the conditions of [reductant]0 ≫ [Ag(III)]0, the plots of ln(AAtt − AA∞) versus time were straight lines, indicating the reaction is rst order with respect to [Ag(III)], where AAtt and AA∞ are the absorbance at time t and at in nite time, respectively. e pseudo- rst-order rate constants kkobs were calculated by the method of least squares

Summary

Introduction

Many researchers from many countries are interested in the study of the highest oxidation state of transition metals which in a higher oxidation state generally can be stabilized by chelation with suitable polydentate ligands. The mechanism of the oxidation of triethylene glycol and tetraethylene glycol by DTA is reported Both of triethylene glycol and tetraethylene glycol which serve as thinners, solvent, and dispersant, are used in coatings, inks, printing, dyeing, pesticide, cellulose and acrylic acid industry, and so forth. They can be used as fuel antifreeze, cleaning agents, the extractant, nonferrous metal dressing agent and organic synthetic materials, and so forth

Experimental

Results and Discussion

Conclusion