No abstract

Herein, we report for the first time simultaneous hydrolysis during the phase-transfer-catalyzed synthesis of butyl 4-methoxyphenylacetate using potassium hydroxide in biphasic medium. Effect of operating parameters on the reaction is presented. The yield of ester increases with the increase in the agitation speed up to 500 rpm and above that the conversion is not influenced by the agitation speed. At higher concentration of base, the hydrolysis product is more favored. Lower temperature and larger volume of water favors the esterfication. At high concentration of catalyst, sharp decrease in the yield of the ester is noticed. In the presence of highly polar solvents, the conversion of ester increases initially and then there was a sharp decrease. Rational explanations to account for the phenomena based on the results are made.

In this paper, we present an experimental protocol for following the kinetics of phase‐transfer catalyzed synthesis of butyl 2‐(4‐methoxyphenyl) acetate from the esterification of 4‐methoxyphenylacetic acid with the presence of potassium hydroxide as a base and potassium carbonate by gas chromatography. Hydrolysis of the ester product was curtailed by using low concentration of potassium hydroxide and potassium carbonate (inorganic salt) during esterification. The reaction is greatly enhanced by adding a small quantity of phase‐transfer catalyst (kapp = 4.75 × 10−3 min−1). Rate of esterification was investigated at various experimental parameters, namely. stirring speed, amount of catalyst, different solvents, different volumes of water, different inorganic salts, different phase transfer catalysts and temperature. When the degree of agitation exceeded 20.93 rad.s−1, the mass transfer resistance for the reaction can be ignored. As the catalyst amount was increased (from 0.5 to 1.2 g), the rate constant values also increased (from 2.32 × 10−3 min−1 to 6.13 × 10−3 min−1). A kinetic model was proposed for the esterification, and the experimental data were well described by the pseudo‐first‐order equation. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.