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Esterification of free fatty acids to biodiesel over heteropolyacids immobilize...
Tropecêlo, A; Casimiro, M; Fonseca, I; Ramos, A; Vital, J; Castanheiro, JoseTungstophosphoric acid (PW), molybdophosphoric acid (PMo) and tungstosilicic acid (SiW) immobilized on SBA-15 were used, as catalysts, in the esterification of palmitic acid with methanol, at 60 ◦C. Catalysts were characterized by N2 adsorption, FTIR, X-ray diffraction, ICP-AES and TEM. All catalysts exhibited high catalytic activity in palmitic acid esterification with methanol. It was observed that the cataly...
Methoxylation of alpha-pinene over heteropolyacids immobilized in silica
Pito, DS; Matos, I; Fonseca, I; Ramos, A; Vital, J; Castanheiro, JoséThe methoxylation of a-pinene was studied using heteropolyacids immobilized on silica as catalysts, at 60 ºC, being the a-terpinyl methyl ether the main product. Tungstophosphoric acid (PW), molybdophosphoric acid (PMo), tungstosilicic acid (SiW) and molybdosilicic acid (SiMo) were immobilized on silica by sol–gel method. It was observed that the catalytic activity of the silica-supported heteropolyacids decrea...
Esterification of glycerol with acetic acid over dodecamolybdophosphoric acid e...
Ferreira, P; Fonseca, I; Ramos, A; Vital, J; Castanheiro, JoseThe esterification of glycerol with acetic acid was carried out over dodecamolybdophosphoric acid (PMo) encaged in the USY zeolite. The products of glycerol acetylation were monoacetin, diacetin and triacetin. A series of PMo encaged in the NaUSY zeolite with different PMo loading from 0.6 to 5.4 wt.% were prepared. It was observed that the catalytic activity increases with the amount of PMo immobilized in the ...
Methoxylation of -pinene over poly(vinyl alcohol) containing sulfonic acid groups
Pito, D; Fonseca, I; Ramos, A; Vital, J; Castanheiro, JoséThe methoxylation of a -pinene was studied using poly(vinyl alcohol) (PVA) containing sulfonic acid groups as catalysts. These groupswere introduced by the direct reaction between –OH groups of PVA and sulfosuccinic acid (SSA). Poly(vinyl alcohol) catalysts were prepared using sulfosuccinic acid by varying the amount of SSA (5–40 mol%). It was observed that the amount of acid sites increases with amount of SSA....
Esterification of free fatty acids with methanol using heteropolyacids immobili...
Caetano, C; Fonseca, I; Ramos, A; Vital, J; Castanheiro, JoseThe esterification of palmitic acid with methanol was studied using tungstophosphoric acid (PW), molibdophosphoric acid (PMo) and tungstosilicic acid (SiW) immobilized by sol–gel technique on silica, at 60 º C. It was observed that the catalytic activity decreases in the series: PW-silica > SiW-silica > PMo-silica. A series of PW immobilized on silica with different PW loadings from 2.5 wt.% to 8.4 wt.% were pr...
Acetoxylation of camphene catalysed by beta zeolite
Castanheiro, Jose; Fonseca, I; Ramos, A; Vital, JBeta zeolite with Si/Al ratio equal to 40 was synthesised and used as solid catalyst in acetoxylation of camphene. The main product of camphene acetoxylation was isobornyl acetate being also formed bornyl acetate and fenchyl acetate. Effects of various parameters, such as reactant molar ratio, reaction temperature, catalysts loading and reusability of the catalyst were studied to optimise the reaction condition...
REDE C3 - Crescer com Ciência. Uma rede regional para promover o ensino experim...
Figueiredo, Margarida; Candeias, António; Martins, Maria do Rosário; Castanheiro, JoséA comunicação refere-se à criação de uma rede regional de experimentação nas escolas do 1º Ciclo do Ensono básico que tem como objectivos o ensino e a divulgação das Ciências, em particular da Química
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