Sonication effects on ester hydrolysis in alcohol–water mixtures; 199-206Full article in PDF format | 10.3176/chem.2007.4.04
Kinetics of the neutral hydrolysis of 4-nitrophenyl chloroacetate was investigated in water and in the presence of 1 mol % of ethanol, propanol, and n-butyl alcohol without sonication and under ultrasound at 25 kHz. Similarly, the kinetics of the acid-catalysed hydrolysis of n-propyl acetate in ethanol–water binary solutions was investigated without sonication and under ultrasound at 22 kHz. The results are discussed together with corresponding data for ethyl and n-butyl acetate from previous works. It was concluded that for ester hydrolyses the solvent effects in an aqueous alcohol binary mixture are limited almost entirely to the hydrophobic ground-state stabilization by the organic co-solvent.
1. Luche, J. L. Synthetic Organic Sonochemistry. Plenum Press, New York, 1998.
2. Cravotto, G. & Cintas, P. Power ultrasound in organic synthesis: moving cavitational chemistry from academia to innovative and large-scale applications. Chem. Soc. Rev., 2006, 2, 180–196.
3. Mason, T. J., Lorimer, J. P. & Mistry, B. P. The effect of ultrasound on the solvolysis of 2-chloro-2-methylpropane in aqueous ethanol. Tetrahedron,1985, 41, 5201–5204.
4. Lorimer, J. P., Mason, T. J. & Mistry, B. P.Effect of ultrasound on the solvolysis of 2-chloro-2-methylpropane in aqueous alcoholic solvents. Ultrasonics, 1987, 25, 23–28.
5. Tuulmets, A. Ultrasound and polar homogeneous reactions. Ultrason. Sonochem., 1997, 4, 189–193.
6. Tuulmets, A. & Salmar, S. Effect of ultrasound on ester hydrolysis in aqueous ethanol. Ultrason. Sonochem., 2001, 8, 209–212.
7. Hagu, H., Salmar, S. & Tuulmets, A. Ultrasonic acceleration of ester hydrolysis in ethanol–water and 1,4-dioxane–water binary solvents. Proc. Estonian Acad. Sci. Chem., 2002, 51, 235–239.
8. Tuulmets, A., Salmar, S. & Hagu, H. Effect of ultrasound on ester hydrolysis in binary solvents. J. Phys. Chem. B, 2003, 107, 12891–12896.
9. Salmar, S., Cravotto, G., Tuulmets, A. & Hagu, H. Effect of ultrasound on the base-catalyzed hydrolysis of 4-nitrophenyl acetate in aqueous ethanol. J. Phys. Chem. B, 2006, 110, 5817–5821.
10. Hagu, H., Salmar, S. & Tuulmets, A. Impact of ultrasound on hydrophobic interactions in solutions: ultrasonic retardation of benzoin condensation. Ultrason. Sonochem., 2007, 14, 445–449.
11. Tuulmets, A., Hagu, H., Salmar, S., Cravotto, G. & Järv, J. Ultrasonic evidence of hydrophobic interactions. Effect of ultrasound on benzoin condensation and some other reactions in aqueous ethanol. J. Phys. Chem. B, 2007, 111, 3133–3138.
12. Nishi, N., Takahashi, S., Matsumoto, M., Tanaka, A., Muraya, K., Takamuku, T. & Yamaguchi, T. Hydrogen bonding cluster formation and hydrophobic solute association in aqueous solution of ethanol. J. Phys. Chem., 1995, 99, 462–468.
13. Egashira, K. & Nishi, N. Low-frequency raman spectroscopy of ethanol–water binary solution: evidence for self-association of solute and solvent molecules. J. Phys. Chem., 1998, 102, 4054–4057.
14. Wakisaka, A., Komatsu, S. & Usui, Y. Solute–solvent and solvent–solvent interactions evaluated through clusters isolated from solutions: preferential solvation in water–alcohol mixtures. J. Mol. Liq., 2001, 90(1–3), 175–184.
15. Buurma, N. J., Pastorello, L., Blandamer, M. J. & Engberts, J. B. F. N. Kinetic evidence for hydrophobically stabilized encounter complexes formed by hydrophobic esters in aqueous solutions containing monohydric alcohols. J. Am. Chem. Soc., 2001, 123, 11848–11853.
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