- Title
- Characterisation of heterogeneous acid/base catalysts and their application in the synthesis of fine and intermediate chemicals
- Creator
- Li, Jerry Pui Ho
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2014
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The catalytic treatment of volatile organic compounds in the form of aliphatic and aromatic hydrocarbons was investigated on different heterogeneous catalysts. With the aliphatic hydrocarbons, a transesterification reaction between methanol and ethyl acetate was conducted using an MgO-BaO composite catalyst. The catalyst was catalysing the reaction but the work highlighted a knowledge gap regarding the mechanistic pathway. The study was extended to the catalytic treatment of an aromatic hydrocarbon, benzaldehyde, applying the Knoevenagel condensation reaction. SiO₂, γ-Al₂O₃, ZnO, Fe₂O₃ supports impregnated with Mg and Ba were used as catalysts Based on the TOF of the reaction, catalysts with the high TOF values had fewer base sites, showing high catalytic activity per site, but also high rate of deactivation. Most interestingly, over ZnO modest TOF values were obtained but the highest concentration of base sites per area was found. ZnO as a catalyst was further investigated, using in situ FTIR and TPD-MS to observe benzaldehyde and ethyl cyanoacetate adsorption and desorption on the surface. Most interestingly, benzaldehyde and ethyl cyanoacetate form intermediate species that are stabilised on the surface, which play an important role in the reaction mechanism. TPD-MS showed the intermediates are thermally stable on the catalyst surface. Finally the catalytic treatment of phenol through a hydroxylation reaction with H2O2 as oxidant over-MFI, Fe-MFI, H-BEA, Fe-BEA and TS-1 zeolite catalysts was investigated. Over H-BEA, biphenyl product was observed. It is suggested, that the larger pore size of H-BEA facilitates coupling of two phenol molecules. Two distinct mechanistic pathways are proposed for acid and redox catalysts.
- Subject
- heterogeneous catalysis; characterisation; alkaline earth metal oxides; zinc oxide; Knoevenagel condensation; transesterification; hydroxylation; acidity; basicity; in situ FTIR; TPD; zeolites
- Identifier
- http://hdl.handle.net/1959.13/1049156
- Identifier
- uon:15000
- Rights
- Copyright 2014 Jerry Pui Ho Li
- Language
- eng
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