Browsing by Author "Mendes, Marta"
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- Effect of phenolic compounds on the synthesis of gold nanoparticles and its catalytic activity in the reduction of nitro compoundsPublication . Alegria, Elisabete; Da Costa Ribeiro, Ana Paula; Mendes, Marta; Ferraria, Ana Maria; Rego, Ana; Pombeiro, ArmandoGold nanoparticles (AuNPs) were prepared using an eco-friendly approach in a single step by reduction of HAuCl4 with polyphenols from tea extracts, which act as both reducing and capping agents. The obtained AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis), and X-ray photoelectron spectroscopy (XPS). They act as highly efficient catalysts in the reduction of various aromatic nitro compounds in aqueous solution. The effects of a variety of factors (e.g., reaction time, type and amount of reducing agent, shape, size, or amount of AuNPs) were studied towards the optimization of the processes. The total polyphenol content (TPC) was determined before and after the catalytic reaction and the results are discussed in terms of the tea extract percentage, the size of the AuNPs, and their catalytic activity. The reusability of the AuNP catalyst in the reduction of 4-nitrophenol was also tested. The reactions follow pseudo first-order kinetics.
- Fragmento: esboços para uma configuração do conceito literatura e cinemaPublication . Mendes, MartaO fragmento não é um género literário mas uma prática: o princípio da descontinuidade associado ao fragmento assume-se como uma forma de pensamento oposta à linearidade, baseada nos princípios da identidade, continuidade, ordem e simplificação.
- Liquid phase oxidation of xylenes catalyzed by the tripodal C-scorpionate iron(II) complex [FeCl2{κ3-HC(pz)(3)}]Publication . Mendes, Marta; Da Costa Ribeiro, Ana Paula; Alegria, Elisabete; Martins, Luisa; Pombeiro, ArmandoA simple and mild (room temperature) process for oxidation of o-, m- or p-xylene to the corresponding methylbenzyl alcohols, tolualdehydes and toluic acids, using H2O2 (30% aqueous solution) and the iron(II) C-scorpionate [FeCl2{κ3-HC(pz)3}] (pz = pyrazol-1-yl) catalyst is presented. Remarkably, after 5 min of reaction an overall oxygenates yield of 22% (TOF = 1.3 × 102 h−1) was obtained. The effects of reaction parameters, such as reaction time, temperature, amount of catalyst, type and amount of oxidant are reported and discussed.
- Porquê e para quê: Rhinocervs - cinema, dança, música, teatroPublication . Vaz, João; Xavier, Madalena; Cordeiro, Marta; Mendes, Marta; Morais-Alexandre, PauloA revista científica RHINOCERVS - Cinema, Dança, Música, Teatro é uma publicação científica do Politécnico de Lisboa e das suas Escolas das Artes: Escola Superior de Dança, Escola Superior de Música de Lisboa e Escola Superior de Teatro e Cinema. Pretende ser um fórum para todos quantos queiram publicar e divulgar as suas investigações, percorrendo as temáticas da performance, composição, criação, design de cena, escrita dramática e cinematográfica, dos pontos de vista estético, histórico, filosófico, técnico, pedagógico-didático ou reflexivo, bem como as diferentes relações entre as formas artísticas e as artes intermediais.