Microwave Chemistry Reactor

Figure 1.

Warlock Engineering Applicator Model: MDV2.4

Download PDF Version of this Document

Abstract

In the course of investigations into microwave assisted chemical reactions, problems were encountered due to the reaction scale upon which many commercial reactors are currently operating. Obtaining reasonable quantities of material (above 10 g) became laborious and it was also discovered that many solvents with low dielectric absorption were heated due to the ferrite core of the stirrer bar heating up. Design, simulation and testing of a small spherical shaped reactor, suitable for 250 ml flask size, was constructed and used in ongoing synthetic work. Microwave suppression was incorporated in the top of the sphere, allowing powers of 1.5 kW to be used without any microwave leakage. The findings were in agreement with simulated results, which showed that the leakage was below detection (1 mW/cm²) from the top, and the detected 2 mW/cm² at the junction was reduced to below 1 mW/cm²

Keywords: Chemistry, Microwave, Microwave Chemistry Reactor

Microwave Chemistry Reactor

A 2.45 GHz simulation of the reactor during the microwave heating of DMF (120 mL). The low pass filter design in the top hemisphere prevents microwave leakage through the top of the vessel, as indicated by the blue color (<1 mW/square cm).

A number of holes were included so that the reaction could be observed through the side of the sphere and in future development more viewing holes will be included to give the user a clear view of the reaction in progress. Variable power was provided by a 2450MHz, 0 - 700 Watt microwave generator (2m172). Magnetic stirring was achieved by ferrite stirrer beneath the applicator, with a teflon coated follower inside the vessel. Further developments are in progress.