Ultrasound Assisted Synthesis of 4-Benzyloxy-3-methoxybenzaldehyde by Selective O-Alkylation of Vanillin with Benzyl Chloride in the Presence of Tetrabutylammonium Bromide

Abstract

Cavitational reactors are a novel and promising form of multiphase reactors, based on the principle of the release of a large magnitude of energy due to the violent collapse of the cavities, which can be effectively applied for intensification of chemical synthesis. In the present work, 4-benzyloxy-3-methoxybenzaldehyde has been synthesized by selective O-alkylation of vanillin with benzyl chloride using tetrabutylammonium bromide-based phase transfer catalysis in the presence of ultrasonic irradiations. The reactions were performed in a 150 cm3 capacity glass reactor equipped with reflux condenser, and ultrasonic irradiations were introduced using an ultrasonic horn operating at a frequency of 20 kHz with a power rating of 120 W. The effects of different operating parameters such as quantum of aqueous phase, temperature, catalyst loading, ultrasonic power dissipation, and molar ratio of reactants have been investigated with an aim of maximizing the extent of synthesis of 4-benzyloxy-3-methoxybenzaldehyde...