Department of Chemistry,University of Karachi
The study of non-catalyzed molecular reaction of reducing sugars by spectrophotometry technique at different concentration of sugars, iodine and temperature has investigated first time. The absence of salt effect indicates that the reaction does not take place between ionic substances, and that at least one of the reactants must be non-ionic. This adds further confirmation to the hypothesis that the reaction takes place directly between the sugars and hypoiodous acid. The results indicate that the reaction is first order kinetics with respect to sugars and hypoiodous acid but it is zero order kinetic with respect to iodine concentration. The low value of energy of activation confirmed the presence of neutral molecules in rate determining step, and the negative value of entropy shows that the process is not spontaneous but the reverse process is spontaneous at all temperatures. Thermodynamic parameters have evaluated by studying kinetics at various temperatures. Suitable mechanism has proposed in consistency with the kinetic results.
Key words: non-catalyzed, molecular reaction, reducing sugar, spectrophotometry technique, hypoiodous acid, kinetics.