The Effects of Surfactants on Hydrolysis of γ-Valerolactone

Abstract

The kinetics of hydrolysis of γ-valerolactone in aqueous solution in the presence of cationic, anionic and nonionic surfactants, NaC1, and Na₂SO₄, were studied at 0.0, 2.5 and 5.0°c. From the rate constant (kobs), In PZ and the other thermodynamical parameters were evaluated for each type of the surfactants. As the rate of hydrolysis was slightly increased by the addition of the above surfactants, E_A, ΔS_A and In PZ were decreased. While ΔF_A remained unchanged as compared with the case of no addition of the above surfactants. A linear relationship between E_A and ΔS_A as well as ΔS_A and log CMC, was observed. Enhancement effects of the surfactants were observed in the following : cationics>nonionic (PONPE 30)>anionic (SDS), NaCl, Na₂SO₄ none additive>anionic (SDBS)>nonionic (PONPE 15). From the results mentioned above, it is concluded that the substrate and OH^- were slightly concentrated at the micelle, followed by the decrease in the rate of hydrolysis.