An improved sonochemical reactor

The design and optimization of sonochemical apparatus are still open to advancement. Under high-intensity ultrasound reaction rates and yields are mainly influenced by the characteristics of transducer and reactor. Several useful improvements are introduced and described. In order to achieve uniformity of the acoustic field and optimal acoustic streaming in every part of the reaction vessel (a Teflon((R)) tube), the reactor can be made to rotate eccentrically around the horn axis and the probe to move alternatively up and down by a pre-determined excursion at a chosen speed. Continuous high-power irradiation is feasible without any time limit because the whole probe system is refrigerated by an oil forced-circulation circuit connected to a chiller. The apparatus can control a number of important reaction parameters: modified atmosphere, reaction temperature, tunable frequency and constant amplitude. Excellent performance was observed on several reactions, such as the chemical modification of chitosan, a poorly soluble biopolymer. (C) 2004 Elsevier B.V. All rights reserved.