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ABSTRACT:
The effect of different composition of a water-Ehtylene glycol solvent on kinetics of amyl methanoate formate was studied at different temperature ranging from 20 to 40°C.The rate constant decreased with increase of water fraction in the solvent from 20 to 80%.The considerably change was found in activation parameters enthalpy of activation (AH·) and entropy of activation (AS·) and free energy of activation free energy of activation (AG·) with increasing mole %, which indicates that there is specific salvation taking place with change of solvent composition. The iso kinetic temperature was found to be 253.84 K/Mole2 which is less than 300, indicates weak solvent solute interaction in the reaction media.
KEYWORDS: Kinetics, water-ethylene glycol, activation parameter, ionic strength, Amyl methanoate formate.
1. INTRODUCTION:
The kinetic studies of on acid canalized hydrolysis of amyl methanoate in binary aqueous mixture have revealed that the reorganization of the solvent surrounding the reactant in the activation processes greatly influences the reaction rate. Such reorganizations are affected by the addition of co-solvent its effect cannot. However, be treated as mere diluents of water modifying its dielectric properties only. In this project we have studied the solvent effect on kinetics of acid catalyzed amyl methanoate formate (which is used as flavoring agent in food) in varying composition of waterethylene glycol mixture at different temperature.
The effect of aquo-organic solvent on kinetic behavior of acid catalyzed can be of major importance in controlling reaction rate which is usually affected by specific interaction of the solvent with the reactant and with transition state. The dielectric constant of ethylene glycol is lesser than water, being miscible with water in all proportion and hence, varying composition of water solvent mixture will have different dielectric constant values lower than water [1-3]. Properties of solvent alone, do not necessary predict the reaction and many workers [4-10], in attempt to correlate the rate change with nature and properties of the solvent medium have conflicting results. Thus Parker [11] and Robert [12] found that rate constant values decreases in the system with increases dielectric constant in the medium, in contradiction to the predictions of Hughes and Ingold [13] and Laidler and Landskroener [14], that rate of such reaction is expected to rise with increase of dielectric constant.
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