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-Asymmetric alumina hollow fibres produced by the phase inversion/sintering method present advantages in that high area/volume ratios and low mass transfer resistances are achieved due to the geometric configuration and the pore size distribution, respectively. Here we characterise hollow fibres that were prepared with different internal coagulants and at different sintering temperatures. Additionally, a palladium membrane was deposited on these different hollow fibres and hydrogen permeabilities through them were compared. More fingers were obtained when a mixture of solvent with water was used as internal coagulant, instead of pure water. At the same sintering temperature, nitrogen permeance through the fibre was increased 5-fold when a mixture of solvent and water was used as internal coagulant instead of pure solvent, and the water flux was increased 7-fold. The decrease in the sintering temperature increased the water permeance through the fibre from 21.4 to 63.9 L h when using a more permeable hollow fibre as substrate. These results elucidate better conditions to fabricate hollow fibres that present low mass transfer resistances.

In the past few decades, biodiesel has emerged as a promising renewable energy source. However, its production usually leads to the formation of large amounts of glycerol as a byproduct. This article reports the evaluation of catalytic glycerol etherification with ethanol over a series of catalysts in a continuous reactor. Amberlyst 15 presented the best performance in terms of glycerol conversion and yield of ethers. This result was attributed to its high pore size and acidity. Beta zeolite (Si/Al = 12.5) and niobic acid, both with lower acid strengths and pore sizes, were almost inactive in the conversion of glycerol into ethers. A central composite design was developed to optimize the performance of Amberlyst 15. An increase in catalyst amount enhanced both the glycerol conversion and the yield of ethers. However, high temperatures and low molar ratios favored side reactions. The optimized value for glycerol conversion was 91%, and that for the yield of ethers was 13%, under different reaction conditions.

Calophyllum brasiliense is a rich source of bioactive coumarins, xanthones and biflavonoids. The aim of the study was to compare the phenol contents and the antioxidant activity of C. brasiliense extracts obtained by conventional and supercritical fluid extraction (SFE) methods, as well as the quantification of crude extracts and (−)-mammea A/BB yields. Dichloromethane and hexane were used as solvents for the conventional extractions and SFE was developed using supercritical CO 2 ; the kinetic curves were modeled using a second-order empirical model. The dichloromethane extract presented the best total yield, although it showed the lowest content of (−)-mammea A/BB. The concentration of the coumarin was considerably higher in extracts obtained by the supercritical fluid method and a higher antioxidant activity was assigned to extracts obtained by this technique. Concerning the total phenolic contents, both the dichloro-methane OPEN ACCESSMolecules 2013, 18 6216 and the supercritical extractions produced satisfactory amounts. The SFE method proved to be more promising than conventional methods.

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