A series of active and selective MCM-41 supported catalysts have been successfully prepared and used for bioderived glycerol esterification with acetic acid to produce fuel additives. In the synthesis of MCM-41, an acidic hydrothermal synthesis route was used, and silicotungstic acid (STA) and zirconia (ZrO2) were added to the catalyst structure by wet impregnation. X-ray diffraction, nitrogen adsorption-desorption methods, scanning electron microscopy with energy-dispersive spectroscopy, and inductively coupled plasma-mass spectrometry analysis were used for characterizations of the catalysts. Diffuse reflectance infrared Fourier transform spectroscopy analyses of pyridine-adsorbed catalysts owns Lewis and Brønsted acidity hosting in one, which promotes the esterification reaction of glycerol into glycerol esters with high selectivity. Esterification of glycerol reactions were performed at temperature intervals of 105°C–200°C, with an amount of catalyst equal to 0.5 g, and glycerol/acetic acid molar ratio of 1:6 in a stirred autoclave reactor operated batchwise. STA and ZrO2-impregnated MCM-41 catalysts showed better performance with a complete glycerol conversion and high selectivity to triacetin.

No abstract

Dehydration studies of borax penta-and decahydrate minerals were carried out using a microwave (MW) heating system. A 650 W microwave oven (2450 MHz) as well as a 1600 W convective heating unit was used. It was possible to produce 97.5% Na2B4C>7 anhydrous borax products. Preheating affected both the quality and dehydration time of the end products. The dehydration was found to be very fast up to 2 mol of water after which its speed dropped progressively. Overall microwave heating produced cleaner products and was much faster than the conventional heating system.

Acetates of glycerol have been produced in a heterogeneous reaction system using acidic ion-exchange resin catalysts; Amberlyst-15 (A-15), Amberlyst-16 (A-16), Amberlyst-36 (A-36), Amberlite-IR 120 (A-IR 120) and Relite-EXC8D (R-EXC8D). Effect of reaction temperature on glycerol conversion and product (mono, di and tri glycerol acetates) selectivities were investigated via reaction experiments conducted with glycerol to acetic acid initial molar ratio (G/Ac) of 1/6. Increase in glycerol conversion with an increase in temperature was observed for all catalysts. Among the catalysts investigated, R-EXC8D exhibited the highest activity in the temperature range of 95–150°C. Reaction was completed within a 25 minute short time period.