Browsing by Author "Maya, Eva M."

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    Effect of thiophene, furan moieties and zinc ions on melamine-based porous polyaminals properties and catalytic activity on CO2 cycloaddition reaction
    (2022) Sobarzo, Patricio A.; Tundidor, Alain; Sanz-Perez, Eloy S.; Terraza, Claudio A.; Maya, Eva M.
    A new series of melamine-based porous polyaminals containing thiophene or furan moieties of different size in the polymer network were prepared and fully characterized. The new polyaminals were N-rich polymers with nitrogen content between 10 and 28%, exhibited micro-, meso- or macroporosity, depending on the type and size of the thiophene or furan moiety with specific surface areas in the range of 23-490 m(2)/g. The CO2 uptakes were moderated, between 1 and 5% and those polyaminals with higher CO2 uptake capacity were selected as catalysts to promote the conversion of CO2 into cyclic carbonate and also to prepare the corresponding zinc complexes, which were used as catalysts in the same reaction. The selected catalysts showed good catalytic performance working under much milder reaction conditions (CO2 pressure of 4 bar, 80 degrees C, 0.1 mol % of cocatalyst) than the examples of melamine-based polyaminals published so far for this reaction.
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    Microwave-assisted melamine-based polyaminals and their application for metal cations adsorption
    (2021) Sandin, Ricardo; Gonzalez-Lucas, Maria; Sobarzo, Patricio A.; Terraza, Claudio A.; Maya, Eva M.
    Three new cross-linked melamine-based polyaminal networks containing phenyl (MA-iPh), pyridine (MA-Py) or thiophene (MA-Th) moieties were easily prepared by microwave irradiation (MW) in shorter reaction times (between 1.5 and 4 h) than conventional heating (72 h). The networks showed high nitrogen content (27-37%), specific surfaces between 34 and 424 m(2)g(-1) and high thermal stability (300 degrees C). The adsorption capacity of these polyaminals was determined over different toxic metals such as Cr(VI), Cu(II), Cd (II) and Pb(II) at different pH. The results showed greater chromium adsorption capacity in acid medium (pH 2), while the divalent cations were mainly adsorbed at pH 5. MA-Py that displayed the highest nitrogen content (37%) and highest specific surface area (424 m(2)g(-1)) also showed the highest adsorption capacities of this series, with values of 27.22, 26.42, and 53.13 mg/g for Cr(VI), Cd(II) and Pb(II); respectively. Additionally, MA-Py and MA-iPh with adsorption capacities of 29.12 and 25.02 mgg 1 for Cr(VI) and Cd(II), were competitive in terms of adsorption capacities regarding commercial ion exchange-resins which shown adsorptions in the range 13.7-21.3 mg/g.
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    Silylated oligomeric poly(ether-azomethine)s from monomers containing biphenyl moieties: synthesis and characterization
    (2018) Tundidor Camba, Alain; Sarabia Vallejos, Mauricio; Tagle Domínguez, Luis Hernán; Hauyón Sepúlveda, René Alejandro; Sobarzo Aucal, Patricio Antonio; González Enríquez, Carmen; Ortiz Álvarez, Pablo Andrés; Terraza Inostroza, Claudio; González Enríquez, Carmen; Maya, Eva M.; Tundidor Camba, Alain; Sarabia Vallejos, Mauricio; Tagle Domínguez, Luis Hernán; Hauyón Sepúlveda, René Alejandro; Sobarzo Aucal, Patricio Antonio; González Parra, Alexis Antonio.; Ortiz Álvarez, Pablo Andrés; Terraza Inostroza, Claudio; González Enríquez, Carmen; Maya, Eva M.