Flow Microwave Reactor Research Articles

Continuous flow processing from microreactors to mesoscale: the Bohlmann–Rahtz cyclodehydration reaction

The cyclodehydration of a number of Bohlmann-Rahtz aminodienones exemplifies the use of continuous flow processing to transfer operations from commercial microreactors and microwave batch reactors to mesoscale production using different technology platforms, including a microwave flow reactor.

Controlled formation and size-selected deposition of indium nanoparticles from a microwave flow reactor on semiconductor surfaces

Indium nanoparticles were synthesized in a microwave flow reactor by thermal decomposition of trimethylindium. The particles were extracted from the gas phase by molecular beam sampling, deflected in an electric field, and deposited on a semiconductor surface. The size of the deposited particles was selected by adjusting the deflection voltage. The geometric standard deviation of the size-selected particles was found to be smaller than 10%. The deposition method is compatible with epitaxial growth methods and enhances their potentials with nanoparticle technology.

A Simple Continuous Flow Microwave Reactor

A new simple procedure for microwave-assisted organic synthesis under continuous flow processing has been developed for use in a monomodal microwave synthesizer with direct temperature control using the instrument's in-built IR sensor. This design makes optimum use of the standing wave cavity to improve the energy efficiency of microwave-assisted flow reactions.

Study of the thermal repartition in a microwave reactor: application to the nitrobenzene hydrogenation

In this paper, heat source modelling of a microwave reactor is carried out thanks to electromagnetic simulation software HFSS ®. Thermal modelling of a chemical reactor under microwave irradiation represents an effective way to anticipate this type of heating. In the case of heterogeneous medium, controlling catalyst heating is essential for homogeneous heating and industrial applications. In a simplified case, modelling results are compared with experimental measurements and found to be in accordance with one another. In a second section, a new continuous flow microwave reactor under pressure is presented. The system can receive fixed, fluidised or circulating bed. Hydrogenation of nitrobenzene over supported palladium is performed.

Esterification of benzoic acid in microwave tubular flow reactor

Acid-catalyzed esterification of benzoic acid with ethanol was investigated in a continuous tubular flow reactor heated by microwaves. The microwave reactor operated at medium pressure and high temperature conditions. Esterification was catalyzed with sulfuric acid and with ion exchange resins. Kinetic parameters of esterification were determined in a stirred glass vessel using conventional heating. A mathematical model was proposed to describe temperature profiles and to predict the conversion of the reaction in the tubular flow microwave reactor. The calculated conversions of benzoic acid based on predicted temperature profiles agree with experimental data. The operating conditions in the microwave reactor allowed us to achieve high conversions at relatively low residence times.

The Role of Selective Heating in the Microwave Activation of Heterogeneous Catmnsis Reactions Using a Continuous Microwave Reactor

This paper deals with the contribution of microwave heating to organic synthesis, especially to estenfication. When the reaction is conducted in a heterogeneous medium and under microwave heating, the reaction rate increases compared to classical heating under the same conditions. This is due to selective heating of the catalyst particles creating hot spots, resulting in an increased reaction rate. The temperature of the reactive site was calculated to be 9–18 K above the bulk temperature. A new continuous flow microwave reactor has been tested in order to show the role of selective heating of the catalyst in the activation of organic reactions under microwave heating.

Environmentally Benign Procedures for the Preparation and Isolation of 3-Methylcyclopent-2-en-1-one

A moderately yielding (50±4%) method for obtaining 3-methylcyclopent-2-en-1-one from hexane-2,5-dione in ≥99·5% purity was developed, using 2·1% (w/v) of aqueous KOH at reflux. However, the yield was increased to 80±5% by using considerably lower concentrations of base (<0·1%) and higher temperature (200°C) with a conventionally heated autoclave or a microwave batch reactor. The preparation was scaled up with a larger autoclave and also with a continuous flow microwave reactor. The dione impurity was removed from the enone by preferential adsorption on an anion-exchange resin in the bisulfite form. The product was recovered from the aqueous phase with a hydrophobic resin. This environmentally benign, non-extractive isolation method has potential for broad applicability in cleaner production.