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The obtaining of bis-quinine, a novel alkaloid dimer, has been successfully achieved starting from quinine and the raw coconut juice (Cocos nucifera) as biocatalyst dimerization-like reaction, in mild conditions, with a mass yield of 64.7% in 72 h. The structural elucidation was made based on the spectral data, mainly by a high-field NMR and a mass spectrometry. In a second step, theoretical calculations were performed, an optimised energy structure of the new compound was obtained, the energy gap of the boundary orbitals (HOMO and LUMO) as well as the chemical reactivity descriptors were estimated.

Al2O3-SiO2 sol-gel coatings of different compositions have been deposited on 316L stainless steel by dip-coating from a sonocatalyzed sol made by the mixture of Al(OC4H9)3 e Si(OC2H5)4 as precursors and ethanol and acetic acid as solvents. The coatings were densified at 600, 800 and 1000°C and characterized by X-rays diffraction. The influence of the coatings on the corrosion behavior of the substrate was tested in 3% NaCl by potentiodynamic polarization curves at 1 mV s(-1). The electrochemical results showed that the films densified at 800 and 1000°C have a better electrochemical behavior than the films densified at 600°C. An increase in the aluminium content improves the behavior of the coatings.

Thin SiO2 films were deposited on 316L stainless steel sheets by a sol-gel method using Si(OC2H5)4 as precursor, absolute ethanol, glacial acetic acid and water as solvents and the application of ultra-sound radiation. After heating up to 800°C in air, the properties of the densified coatings were studied by X-ray Diffraction and FTIR Reflection Spectroscopy. The chemical protection of these coatings against thermal oxidation of the steel in air was determined by weight-gain measurements. Potentiodynamic polarization curves at 1 mV s(-1) in aqueous 15 % H2SO4 solutions at different temperatures were used to analyze the protection of the coatings against acid corrosion of the steel. In both cases, the SiO2 films proved to be very efficient protectors against corrosion. Calculations based on the measured corrosion rate in acid solutions showed that the life-time of the substrate can be increased by a factor of 3 to 5.