In the laboratory under the direction of Prof. Roberto Ballini (where I carried out my PhD work), an ''in-progress'' research project has been under way for the past few years. This project, in the field of eco-friendly chemical processes, aims to develop new synthetic methods which could reduce waste and guarantee cleaner reactions. In the team, my task involved studying new reduced environmental impact processes in C-C and C-X bonding. These new processes have been achieved through solid heterogeneous catalysis and domino reactions, and both these methods are in accordance with Green Chemistry guidelines ''Green Chemistry is the design of chemical products and processes that reduces or eliminates the use and generation of hazardous substances'' In this context, by means of solid heterogeneous catalysis, it is possible to reduce complicated work-up to a simple filtration or to a direct loading onto chromatographic column, avoiding the usage of aqueous layer, extraction with organic solvents and, above all, the application and the formation of salts, like Na2SO4 and NH4Cl. Further, the catalyst is weakly corrosive, shows very low toxicity, provides reaction without the use of any solvent (i.e. the most toxic element in a reaction) and, sometimes, it can be recycled. Domino reactions, defined as: ''the processes of two or more bond forming transformations under widely identical conditions in which the subsequent reactions take place at the functionalities obtained in the former transformation'', offer several advantages, in terms of environmental protection and lowering of costs, that lead to an advance toward eco-friendly systems. In fact, the possibility of producing two or more bonds in the same reaction conditions, instead of isolating every intermediate, diminishes the number of steps and consequently entails a reduction of work-up and purification processes. At the end, besides shortening the whole operation span, it provides a cut in the usage of solvents and reagents with evident decreasing of pollution. Thesis work As mentioned above, the main task of my PhD has been to cooperate to development of new synthetic processes in order to produce new C-C and C-X bonds under eco-friendly conditions. For this purpose aliphatic nitro compounds, thanks to the strong electron-withdrowing power of the nitro group, that guarantees the access using weak conditions to stabilized carbanions and the possibility of using the same group as leaving group, have proved to be good starting materials,compatible with low environmental impact processes.
|Titolo:||Study of Eco-Friendly Conditions and Processes in the Formation of New C-C Bonds by Stabilized Carbanions|
|Data di pubblicazione:||2007|
|Appare nelle tipologie:||Tesi di dottorato (Pregresso)|