Abstract
The purpose of this work is to study the synthesis of primary amines under continuous flow conditions using a heterogeneous catalyst. 10 wt% Pd/C catalyst based on mesoporous synthetic carbon was synthesised and used in the form of micro-packed beds in a structured multichannel compact reactor (developed at the University of Bath) and in a commercially available X-CubeTM flow reactor (developed by ThalesNano). Under continuous flow conditions aliphatic, aromatic and cyclic primary amines were synthesised selectively from aldehydes via a tandem reductive amination - hydrogenolysis process with high conversions (>99%) and very good isolated yields (74 - 99%). In this work, two consecutive structured multichannel reactors at different temperatures (T1 and T2) were used to ensure hight selectivity (100%) towards the desired products. Optimal conditions at a liquid flow rate of 0.2 mL min-1 were obtained with a substrate concentration of 0.2 mol L-1.Kinetic studies on the reductive amination of hydrocinnamaldehyde and hydrogenolysis of (1-phenylethyl)(3-phenylpropyl)amine were studied with a 10 wt% Pd/C catalyst using a multichannel packed-bed reactor. It was shown that it was possible to neglect mass transport limitations and kinetic models based on the Langmuir-Hinshelwood approach were proposed. The model of competitive dissociative adsorption of hydrogen was found to represent the mechanism of the reaction and fitted the experimental data very well. The reaction rate constant ( K*R ), adsorption equilibrium constants (KA and KB) and the apparent activation energy for each reaction were estimated.
The investigation resulted in fundamental information on reactor performance for selected model reactions as well as the development of continuous tandem processes. The results demonstrate that the structured multichannel compact reactor and the commercially available X-CubeTM flow reactor can be used to explore how heterogeneous catalysis may be used to turn a batch reaction into a continuous flow process.
| Date of Award | 22 Apr 2015 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Jonathan Williams (Supervisor) & Pawel Plucinski (Supervisor) |
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