This thesis describes the application of solid catalysis to the Flash Vacuum Pyrolysis (FVP) and Flow Pyrolysis techniques in order to develop preparative scale processes for specific transformations. The development of a dehydration protocol for the transformation of amides to the corresponding nitriles has been successfully achieved. This involves the use of commercially available molecular sieves under FVP conditions. The conditions have been optimised and extended to the analogous dehydration of oximes and utilised in the preparation of a number of aromatic, aliphatic and heteroaromatic nitriles in generally excellent yields of 59-99%. The role of the molecular sieves in the process has been extensively investigated in working towards truly catalytic conditions. Dehydrogeneration-aromatisation of hydroaromatic compounds has been studied under FVP conditions by the use of molybdenum oxide based catalysts. Again, after optimisation, the conditions have been applied to the preparation of a number of aromatic and heteroaromatic compounds. The mechanism of the reaction has been investigated by the application of the method to substrates with appropriate substitution. Because substituents are generally retained in the products formed, it suggests that the dehydrogenation mechanism does not involve discrete free radical intermediates. The so-called "anthranilate rearrangement" of 2-nitrotoluene to anthranilic acid has been investigated. Several stages of the mechanism of this process in the gas-phase have been elucidated using both Flash Vacuum Pyrolysis and Flow Pyrolysis. Various flow pyrolytic conditions have been developed in an attempt to identify and overcome the problem steps of this reaction and to work towards a preparatively useful process.