Catalytic oxidation of n-butane is important in an attempt towards developing economical and environmentally friendly processes for production of maleic anhydride. Methods of preparation of both the vanadium-phosphorus-oxides (VPO) catalyst and an inorganic composite membrane as well as the performance of the membrane obtained have been investigated in this work. The procedure used in the preparation of vanadium-phosphorus-oxides (VPO) catalyst was similar to that described by Katsumoto and Marquis (1979), while a dip coating method was used for preparation of a silica coated y-A^Os membrane from the outside, and the membrane prepared then was tested for permeance using nitrogen and air. The kinetics of the selective oxidation of n-butane to maleic anhydride has been studied over vanadium-phosphorus-oxides (VPO) catalyst in a differential glass reactor in the temperature range of 380 - 480°C and at atmospheric pressure. Apart from maleic anhydride (MA), the other detectable products were carbon monoxide (CO), carbon dioxide (CO2), and air (HhO). Kinetic measurements demonstrated the production of maleic anhydride, carbon monoxide, and carbon dioxide as initial products of the reaction at low n-butane conversion. Under conditions of a large excess of oxygen, the reaction model was represented according to a scheme of three parallel formation reactions. The activation energies for maleic anhydride (MA), carbon monoxide (CO), and carbon dioxide (CO2) production are 61.1 kJ/gmol, 56.1 kJ/gmol, and 70.9 kJ/gmol, respectively. These values of the activation energies are in the same range as those obtained from previous differential reactor studies. The oxidation of n-butane to maleic anhydride also has been compared by using fixedbed and membrane reactors with the same VPO catalyst. The effects of operating conditions on the conversion of n-butane, the selectivity to maleic anhydride, and the yield of maleic anhydride have been studied in detail. A simulation study on the use of fixed-bed and membrane reactors for oxidation of n-butane to maleic anhydride has also been undertaken. The results of a mathematical simulation study were compared with the experimental results. The membrane reactor offers several advantages over the fixed-bed reactor for selective oxidation of n-butane to maleic anhydride. The membrane reactor provides a wider operating range particularly with respect to inlet gas composition. Furthermore, they are inherently safer since n-butane and oxygen feeds can be separated by the membrane. The higher butane concentrations and controlled addition of oxygen along the reactor length by means of a membrane lead to higher product rates. A comparative study of butane oxidation to maleic anhydride in conventional fixed-bed and a membrane reactor show that using a membrane reactor gives a better selectivity and yield of maleic anhydride than the conventional fixed-bed reactor. From the simulation study, the mathematical models for both the fixed-bed and membrane reactors are in good agreement with the experimental results, except for the mathematical model for the fixed-bed reactor when considering the variation of the oxygen/n-butane ratio. For the membrane reactor, both feed n-butane concentration and oxygen/butane ratio are shown to be not sensitive parameters for the mathematical model, while temperature is a key parameter.

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Electron rich N-benzyl glyoxamides bearing at least two ipso-directing groups can be converted into 2-[4.5]-azaspirocyclic cyclohexadienones upon treatment with a thiol, trifluoroacetic anhydride and BF₃-OEt₂, via a dearomatising, thionium ion azaspirocyclisation. A modest preference for the anti-diastereoisomer is commonly displayed. In certain cases, the anti-diastereoisomer is the only isomer formed. Notably the cyclisation is not accompanied by competing isoquinolone formation. The sulfanyl group that is introduced upon spirocyclisation can act as a synthetic handle and a stereocontrol element during manipulations of the framework. A range of oxidative and reductive transformations have been explored. In cases where the spirocyclic cationic intermediate is unstable intramolecular aryl transfer and iminium ion hydrolysis furnishes a-aryl acetamides. Selective C-alkylation and desulfurisation provides a means of accessing functionalised α-aryl acetamides.

There is a great desire for the synthesis of new heteroaromatic compounds, which have a range of applications from pharmaceuticals to materials. These industries require large numbers of heterocyclic derivatives for their screening programmes, however many common routes for the synthesis of aromatic heterocycles do not allow for the flexible introduction of a diverse range of substituents. Our approach involves the use of tetrafluoropyridazine as a scaffold for the synthesis of a diverse range of heteroaromatic systems. Perfluorinated heteroaromatic compounds, such as tetrafluoropyridazíne, are highly reactive towards displacements by nucleophilic species. Sequential nucleophilic aromatic substitution reactions of 4,5,6- trifluoropyridazin-3(2H) one have been studied and a range of polysubstituted systems synthesised. Similarly, reactions of tetrafluoropyridazine with dinucleophiles have been utilised to yield ring-fijsed products, many of which are rare heterocyclic substructures. This approach has allowed the synthesis of a small library of compounds based on the pyridazine ring system with moderate skeletal and substituent diversity. The synthesis of some non-halogenated products by displacement of all ring fluorine atoms has also been reported.

(+)-Vigulariol was isolated in 2005 by Sheu and coworkers off the coast of Taiwan and belongs to the cladiellin (eunicellin) class of the 2-11 cyclised cembranoid family of natural products. Vigulariol along with numerous other members of the cladiellin family have been shown to possess interesting biological properties including cytotoxicity against various cell lines. This thesis presents the total syntheses of (±)-vigulariol and (-)-vigulariol, that were completed in 20 steps respectively in an overall yield of 4.1% and 5.9%. The key steps in the synthesis are; a samarium diiodide reductive cyclisation to furnish a 2,6-syn-5,6-anti tetrahydropyranol, oxonium ylide formation and an intermolecular Diels-Alder cycloaddition to construct the cyclohexyl ring.