Biodiesel is a renewable fuel, a substitute for fossil diesel, which is important for reducing GHG in Brazil. Therefore, this work aims to synthesize and characterize the catalyst using the support of natural zeolite impregnated with K2O and apply it in the production of biodiesel through the transesterification reaction. Through the analysis of characterizations such as XRD, characteristic peaks of Clinoptilolite and Mordenite zeolites were verified in the natural zeolite, in addition to evidencing the characteristic peaks of KI and K2O in this microporous support. Thermal and FTIR analyzes revealed the presence of KI and K2O in the presence of the decomposition region of composite compounds (500 to 800 °C) and corresponding vibration bands, while EDS analysis indicated the efficiency of KI to K2O conversion after calcination. To evaluate the application of the catalyst in the production of biodiesel, the following reaction conditions were studied: percentage of catalyst in relation to oil mass (6% and 8%), methanol:oil mass ratio (15: 1 and 30: 1) and temperature (60 °C and 90 °C). The catalyst presents good results reaching a conversion of 98.96% in esters using 6% catalyst, mass ratio oil:methanol 1:30 and reaction temperature of 90 °C.

ABSTRACT The design of effective CO2 capture materials is a current challenge. Here, we report the synthesis of aminosilanes-functionalized MCM-41 and SBA-15 materials with high efficiency toward carbon dioxide adsorption. The functionalization of the mesoporous silicas involves a post-synthesis method by impregnation with 3-aminopropyltriethoxysilane. The carbon dioxide adsorption capacities for the samples were carried out under ambient pressures. The results evidenced that aminosilanes with a terminal amine were functionalized through covalent coupling of this group onto the channels' surface in the ordered mesoporous silica. It means that the amine is anchored on the surface of the largest pores of the MCM-41 and SBA-15 supports. The Lagergren kinetic model evidenced the enhanced carbon dioxide adsorption capacity and stability of the functionalized ordered mesoporous molecular sieves.

The nature of the solid residue formed in beef tallow biodiesel from two commercial producers in Brazil was determined by comparative analytical techniques, namely, gas chromatography with flame ionization detector (GC-FID) and thermogravimetry (TG). Pure monopalmitin and monostearin were used as reference standards for both methodologies. Analyses were carried out before and after filtration of the solids formed, which allowed the observation that the formation of precipitate reduced the levels of monoglycerides in the beef tallow biodiesel. The chromatographic and thermogravimetric results confirmed the nature of the residue as saturated monoglycerides, predominantly monostearin and monopalmitin.

Iodide potassium incorporated on mesoporous molecular sieves (SBA-15 and MCM-41) was used as heterogeneous catalysts in the transesterification of sunflower oil under different conditions of reaction time and ratio catalyst/oil (w/w). The results have showed that the system supported in SBA-15 has been more active than the supported in MCM-41, promoting a conversion to methyl esters of 84.98%.