Otimização de parâmetros da síntese de silica mesoporosa para viabilizar o escalonamento como suporte catalítico

Abstract

In this work, the synthesis of silica SBA-15 was carried out through acid hydrolysis using a P123 pluronic copolymer directing agent. Sílica samples were prepared through the silicon supports precursor tetraethylortosilicate (TEOS). The liquid phase reduction was investigated for understanding the possibility of scale-up the process. The solids were characterized through X-ray diffraction (XRD) to confirm the formation of the mesophase, by comparing samples prepared under diferente volumes of reduction, named SBA -15-1⁄3, SBA-15-⅔ and SBA-15-1⁄2, at stirring times of 4 h and 24 h. Also, the infrared spectroscopy (FTIR) was used for the samples S1-1⁄3-(4), S2-⅔-(4), S3-1⁄2-(4), S4- ⅔-(24) and S5-½-(24), sand the set of results showed, the presence of siloxane groups, Si-O-Si, OH stretching and water deformation. Therefore, the reductions of the liquid phases proved that the porous structure retains the structure successfully, under drastic conditions through the syntheses. Nitrogen adsorption-desorption (BET) results for the S2 to S4 syntheses showed capillary condensation with H1-type hysteresis and properly homogeneity of the material.