Synthesis of butyl 2‐(4‐methoxyphenyl) acetate in biphasic system using low concentration of potassium hydroxide—kinetic aspects

ABSTRACT 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.