CHARACTERIZATION OF VOLATILE COMPOUNDS IN THE ESSENTIAL OIL OF SWEET LIME ( Citrus limetta Risso)

The essential oil of citrus fruit contains components pleasant sensory characteristics that are appreciated in food, pharmaceutical, and cosmetics industries. In the case of sweet lime ( Citrus limetta Risso), is necessary to characterize the essential oil components, to identify potential uses of this fruit. The essential oil of sweet lime was obtained from lime flavedo in four different maturation stages. Steam distillation was employed and then compared with hexane extraction. The identification of the components in the essential oil was carried out by gas chromatography and mass spectrometry. A total of 46 components were found in the essence of lime, among which the highest concentration of compounds present were aldehydes such as limonene. Linalool, sabinene, and bergamol were more abundant than in other varieties. The best extraction method was steam distillation, and the concentrations in stage III from the main terpenic portion were d-limonene with 74.4%, bergamol with 8.23%, and β-pinene with 7.62%

Catalytic Deactivation of HY Zeolites in the Dehydration of Glycerol to Acrolein

The study of the deactivation of HY zeolites in the dehydration reaction of glycerol to acrolein has represented a challenge for the design of new catalysts. HY zeolites with SiO2/Al2O3 molar ratios between 3.5 and 80 were studied. The solids were characterized by XRD, N2 physisorption, SEM-EDXS, Raman and UV-vis spectroscopies, infrared spectroscopy of pyridine (FTIR-Py) and catalytic activity tests from 250 °C to 325 °C. It was found that the total amount of acid sites per unit area of catalyst decreased as the SiO2/Al2O3 molar ratio increased from 3.5 to 80, resulting in the decrease in the initial glycerol conversion. The initial acrolein selectivity was promoted with the increase of the Brønsted/Lewis acid sites ratio at any reaction temperature. The deactivation tests showed that the catalyst lifetime depended on the pore structure, improving with the presence of large surface areas as evidenced by the deactivation rate constants. The characterization of the deactivated catalysts by XRD, N2 physisorption and thermogravimetric analysis indicated that the deposition of coke resulted in the total obstruction of micropores and the partial blockage of mesopores. Moreover, the presence of large mesopores and surface areas allowed the amount of coke deposited at the catalyst surface to be reduced