Among the Green Chemistry principles are the increase of safety, accomplishment and efficiency of products and processes, especially for the reduction or elimination of physico-chemical properties that characterize the danger to human health and the environment, in addition to propose sustainable ways of industrial processes and medicinal.Through a comparison between the Cyperus rotundus plants species with different chemical profiles, one collected in the residue area of the VALE company in Mina do Sossego in Canaã dos Carajás, an area contaminated by metals, and the other one collected in an adjacent area of Mina do Sossego, without contamination of metals, it was verified, through the results of ICP-AES, that the contaminated plants had a quantity of Cu, among other metals, higher than normal.This fact occurs due to the hyperaccumulative behavior of the species, a characteristic widely used in phytoremediation, a bioremediation technique that consists in the use of plants and their microbiota in the remediation of contaminated soils. In this project, the species Typha domingensis, Pluchea sagittalis and Cecropia pachystachya, also collected from the contaminated areas, will be analyzed as well. Depending on the concentrations of metals obtained, the extracts will be used for the preparation of nanoparticles which will then be employed in catalysis.The project is based on a method described by Liu et al., which shows the recycling of carbon and metals in plants by the synthesis of nanomaterials. They showed that the nanoparticles and nanocomposites of MWCNTs, ZnO and CuO can be synthesized using two types of hyperaccumulators (S. alfredii and B. juncea) as starting materials, without catalyst, through a simple process with plant shoots digested in a mixture of HNO3/HClO4 (4: 1) after removal of the surface particles adhering to the shoots with water; the concentrations of the metals are determined by plasma mass spectrometry.To evaluate the efficiency of the nanocatalysts prepared from the plant extracts, other magnetically recoverable catalysts, CuO.Fe3O4 and g-Fe2O3-b-Cu, will also be prepared and used in Cu-catalyzed multicomponent reactions. The multicomponent reactions are an efficient and widely used way to obtain heterocycles, since they allow the structural diversification without the need of isolation of intermediates, generating new connections in one-pot sequential reactions, allowing a high atomic, generation of waste, thus being a good strategy for the development of sustainable synthetic routes.Depending on the results obtained, the scope and the limitations of the reactions will be analyzed in substrates containing donor or electron withdrawing groups.
News published in Agência FAPESP Newsletter about the scholarship: