The focus of this thesis is the role of the solvent and scale-up upon rate and selectivity in heterogeneous catalysed hydrogenations, which are ubiquitous in the production of fine chemicals and pharmaceuticals. A kinetic method has been developed based on rigorous statistical methods and sensitivity analysis for the catalytic hydrogenation of 4-phenyl-2- butanone in stirred tank reactors at two different scales using Pt/TiO2 and Pt/SiO2 catalysts. In this thesis, modelling carried out for a 100 mL scale reactor was validated against experimental data supplied by Queens University Belfast (QUB). Experimental measurements of rate and selectivity and model validation at a larger 3000 mL scale were both carried out as part of this study. The models were evaluated over a wide range of operational conditions at both scales for Pt/TiO2 catalyst, and by using a systematic kinetic methodology it was possible to identify the dominant reaction route, derive physiochemically meaningful kinetic data and a reduced kinetic model that was applicable to the scale-up. Comprehensive kinetic analysis made it possible to gain some insight into the shift in reaction mechanism upon scale-up. Kinetic investigation of solvent effects was also carried out at the 100 mL scale for a range of solvents (protic, aprotic polar, apolar, ethers, and halogens) and both catalysts, again tested against experimental data supplied by QUB. The dominant effects of solvent on rate and selectivity of the chosen reaction system were identified as the degree of active site availability imposed by competitive adsorption of solvent on catalyst and the extent of which the solvents assist the product desorption from catalyst surface. The solvent effects upon scale-up give the remarkable result of a significant shift in the selectivity of the catalyst towards phenyl ring and ketone hydrogenation groups of 4-phenyl-2-butanone.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:675796 |
| Date | January 2015 |
| Creators | Sedaie Bonab, Nazita |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/6357/ |
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