Obtenção do poli(N-vinilimidazol-co-divinilbenzeno) por copolimerização assistida por micro-ondas e sua aplicação como suporte de cobre em reações click chemistry

• Autor(a) principal: Gomes, Hallan Bruno de Matos Angeira
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/15645
• topic: Polyvinylimidazole; divinylbenzene; polystyryl pyridine; copper supported; click chemistry; Polivinilimidazo; divinilbenzeno; poli(estiril-co-piridina); suporte de cobre; cicloadição; click chemistry; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA::POLIMEROS E COLOIDES

Heterocyclic copolymers containing nitrogen in their structure were synthesized and have been applied as support for CuSO4 to catalyze [3+2] cycloaddition reactions(click chemistry). The polymerizations were performed with the reaction between N-vinylimidazole and divinylbenzene to form poly(N-vinylimidazole-co-divinylbenzene) [PNVI-DVB], underconventional heating and microwave irradiation and without solvent.Poly(styryl-co-pyridine) (PSP) was used for comparison with PNVI-DVB. The activity of each polymer was measured by titration, presenting 4.6 mmol/g of activity for PNVI-DVB and 0.7 mmol/g for the PSP. The elemental analysis showed the degree of nitrogen present in each polymer, 12% (PNVI-DVB) and 5% (PSP). Copper was impregnated in polymer supports by stirring them in a CuSO4 solution. The impregnation power of each polymer was different: PSP (~0,3%) e PNVI-DVB (6,2%). The copolymers with and without Cu2+ impregnated were characterized by FTIR and thermogravimetric analysis (TGA). TGA was applied to copolymers, reaching total mass loss near 470°C (PNVI-DVB) and 540°C (PSP). The surface morphology of the polymers, with and without the metal supported, was studied by using Scanning Electron Microscopy (SEM). The [3+2] cycloaddition reactions, between benzylazide and ethyl propiolate, were performed in the presence of each Cu-supported copolymer under microwave irradiation, obtaining quantitative yields of triazoles and still exhibiting regioselectivity of the 1,4-regioisomer (93% for PNVI- Cu; 88% for PSP-Cu). The polymers were reused for the same reactions up to five times, without decreasing the yields