Radiofrequency (RF) heating of composite magnetic materials enables direct and efficient transfer of energy to the sites of catalytic reactions within a chemical reactor. The materials consist of an RF heated magnetic component and a catalytic component. The two components can be optimised separately according to the demands of the application. This approach was applied to continuous direct amide formation from amines and carboxylic acids under flow conditions, a reaction of great interest and potential to the pharmaceutical industry. The RF heat generation of NiFe2 04-TiO2 magnetic materials were optimised. Catalyst screening showed sulfated commercial P 25 Ti02 to give good catalytic activity in the reaction of 4-phenylbutyric acid with aniline in xylene. The composite material was prepared mechanochemically from a mixture of the optimised magnetic and catalytic components. A continuous RF heated reactor was developed, consisting of a 6 mm diameter insulated micro packed-bed reactor placed within an RF induction coil. The reactor was operated at 7 bar and up to 200°C for up to 10 hours. The sulfated composite achieved t he highest activity of up to 50% conversion in a single pass and the least deactivation. Temperature profiles obtained from the analytical solutions were combined with a catalyst kinetic model to form a reactor model, which was validated by the experimental results. The concentration profiles obtained from the reactor model gave an insight into the mechanism of the observed process intensification - the temperature rise along the RF heated reactor axis helped to offset the reduction in the reaction rate as a result of depletion of the reactants. This novel type of process is therefore most suited to reactions with high reaction rate orders and it would therefore be of great interest to investigate other processes where this effect could be demonstrated.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:676521 |
| Date | January 2014 |
| Creators | Houlding, T. K. |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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