Effect on dipolar protic solvent on the [H⁺] in catalysed hydrolysis of heavier methanoate

The solvent effect of ethanol on the acid catalysed solvolysis of Propyl methanoate (heavier methanoate) was studied by carrying out the hydrolysis of the ester in water-ethanol (EtOH) media of varying composition consisting of 20% to 80% (v/) at different temeratures ranging from 20 to 40°C. The specific rate constant values of the reaction were found to decrease with increasing concentration of ethanol in the reaction media. It was found that with increase in temperature of the reaction from 20 to 40°C from 0.252 to 1.258 molecules of water are associated with the activated complex and from this, it is inferred that medchanistic path followed by the reaction in presence of ethanol is changes from bimolecular to unimolecular. The depletion and enhancement observed respectively in iso-composition and iso-dielectric activation energies reveal that the transition state is solvated and initial state is desolvated with addition of ethanol (EtOH) in The reaction media . Form the values of iso-kinetic temperature, which comes to be 280, it may be concluded that in water-EtOH reaction media, the reaction follows Barclay-Butler rule and theere is weak but acceptable interaction between solvent and solute in the reaction media.