Synthesis of 1-(isopentyloxy)-4-nitrobenzene under ultrasound assisted liquid-liquid phase-transfer catalysis

Abstract

In this paper, we report the reaction of isoamyl alcohol and 1-chloro-4-nitrobenzene was carried out in a batch reactor under aqueous-organic biphasic conditions using the techniques like phase transfer catalysis and ultrasound irradiation. Tetrabutylammonium bromide (TBAB) was employed as the phase transfer catalyst. The reaction is greatly enhanced by adding a small quantity of phase-transfer catalyst under ultrasound (28 kHz, 300W). Detailed kinetics of the etherification was investigated. The rate constants were determined by varying the concentration of the catalyst, stirring speed, the concentration of alcohols, temperature, different solvents, concentration of sodium hydroxide, different inorganic salts and different phase transfer catalysts. From the detailed kinetic study, the optimum reaction conditions to produce higher yield of 1-(isopentyloxy)-4-nitrobenzene was obtained. The experimental data were well described by the pseudo-first-order equation. The individual experiment was carried without ultrasound; the obtained kapp value is 0.0094 min-1. The combination of ultrasound and stirring; the kapp value is 0.0178 min-1. From the observed results, the kapp value for ultrasonically promoted reaction is almost two fold higher than the normal reaction.