Microwave Chemistry Reactor

 

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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 (10g +) 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 250ml flask size, was constructed and used in ongoing synthetic work. Microwave suppression was incorporated in the top of the sphere, allowing powers of 1.5kW to be used without any microwave leakage.  The findings were in agreement with simulated results, which showed that the leakage was below detection (1mW/cm2) from the top, and the detected 2mW/cm2 at the junction was reduced to below 1mW/cm2

 

Keywords: Chemistry, Microwave, Microwave Chemistry Reactor

 

 

 

LIST OF FIGURES

 

Figure

 

Page

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Warlock Engineering Applicator Model: MDV2.4

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Simulation of microwave irradiation of DMF (120ml)

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Warlock Engineering Applicator Model: MDV2.4

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Figure 1. Warlock Engineering Applicator Model: MDV2.4

 

 

 

 

 

 

 

 

Figure 2. Simulation of microwave irradiation of DMF (120ml)

 

 

 

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.

 

 

 

Figure 3. Warlock Engineering Applicator Model: MDV2.4

 

 

 

Specs:

Frequency

2450 MHz

Power

0-1500 Watts

Load

250ml round bottom flask

 

 

 

A prototype of the microwave setup has been on trial for the preparation of synthetic fragrances. Successful preparation of Calone 1951®1 has demonstrated the apparatus to be an efficient design for preparative organic

chemistry when microwave accelerated synthesis is used.

 

 

 

 

1) Microwave assisted synthesis of the fragrant compound Calone 1951®. B. Drevermann, A. Lingham, H. Hügel, P. Marriott. Tetrahedron Letters, 2005, 46,     39-41. doi:10.1016/j.tetlet.2004.11.045