Effect of ultrasound on ester hydrolysis in aqueous ethanol.

Sonication effects on ester hydrolysis in alcohol–water mixtures

Kinetics of the neutral hydrolysis of 4-nitrophenyl chloroacetate was investigated in water and in the presence of 1 mol % of ethanol, propanol, and -butyl n alcohol without sonication and under ultrasound at 25 kHz. Similarly, the kinetics of the acid-catalysed hydrolysis of -propyl n acetate in ethanol–water binary solutions was investigated without sonication and under ultrasound at 22 kHz. ...

Ester containing aggregates in the autocatalytic biphasic hydrolysis of ethyl alkanoate

Autocatalytic kinetics are observed during the biphasic alkaline hydrolysis of C-4, C-6 and C-8 (butanoate, hexanoate and octanaoate) ethyl esters. Ethanol and alkanoate anions are the products of the reaction. A kinetic model including spontaneous dissolution of the organic phase into the aqueous phase, aqueous hydrolysis of the ester, formation of ester containing aggregates and micellisation...

Solvent Effect on Protonation Constants of L-alanine and Alanine Methyl ester in Different Aqueous Solutions of 1,4-Dioxane

The protonation constants of alanine and alanine methyl ester were determined in different aqueous solutions of 1,4-dioxane containing (0-50% v/v), using a potentiometric method at 25o C and constant ionic strength 0.1 mol.L-1 (NaCl). The protonation constants were analyzed in terms of Kamlet, Abboud and Taft (KAT) parameters. The results show that the effect of β is higher in comparison with t...

Origin of Autocatalysis in the Biphasic Alkaline Hydrolysis of C-4 to C-8 Ethyl Alkanoates

The alkaline hydrolysis of C-4 to C-8 (butanoate to octanoate) ethyl esters shows autocatalytic kinetics when performed under two-phase conditions without any mixing solvent. Alkanoate anions and ethanol are the products of the reaction. A dynamic model is proposed that describes quantitatively this kinetic behavior. The model includes the main processes occurring in the biphasic medium and the...

Effect of Ethanol Concentration in Ultrasound Assisted Extraction of Glycyrrhizic Acid from Licorice Root