Preparação e caracterização de microesferas de poli(estireno-co-divinilbenzeno) contendo grupos 2,4,6-trimercaptotriazina para remoção de paládio residual a partir de produtos obtidos em sínteses orgânicas

• Autor(a) principal: Cunha, Henrique Almeida
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/15661
• topic: Poly(styrene-co-divinylbenzene). 2,4,6-trimercaptotriazine. Palladium removal.; Poli(estireno-co-divinilbenzeno); 2,4,6-trimercaptotriazina; Remoção de paládio; Microesferas; Paládio; Síntese orgânica; Polimerização; CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA

In this work, microspheres of poly(styrene-co-divinylbenzene) (PS-DVB) were prepared using the suspension polymerization technique with different levels of DVB (25% and 40%) and degrees of dilution (50% and 100%) using n-heptane diluent as a porogenic agent in order to obtain four different types of porous structures. The microspheres of PS-DVB were subjected to chloromethylation reactions using the paraformaldehyde/HCl(g) chloromethylating system, ZnCl2 as catalyst and 1,2-dichloroethane organic medium. The introduced chloromethyl groups, have a good leaving group and gave rise to the functionalization of the microspheres with the 2,4,6-trimercaptotriazine group (TMT) through a nucleophilic substitution. The materials obtained were characterized by optical microscopy, scanning electron microscopy (SEM), nitrogen adsorption and desorption analysis (ASAP), temogravimetric analysis (TGA). The determination of the content of chloromethyl groups was performed through an alkaline opening and then a return titration (Volhard method). To evaluate the introduction of TMT groups in PS-DVB, elementary CHNS analysis was used. The chemical modifications performed to obtain microspheres of PS-DVB-TMT with different porous structures had the objective of evaluating the efficiency of palladium removal in organic reactions of formation of C C bond that are catalyzed by palladium. Polymeric microspheres containing TMT groups were obtained, these materials had their morphology preserved in relation to the starting materials and showed results of removal of the remaining Pd with values greater than 90%. However, with the atomic absorption technique it was not possible to differentiate between the microspheres of PS-DVB-TMT, in relation to the efficiency in removing the remaining Pd.