Desenvolvimento de materiais híbridos micro-mesoporosos contendo terras raras para utilização no craqueamento de frações de petróleo

Abstract

In recent years there has been a number of innovative procedures to obtain new catalysts cracking of heavy petroleum fractions with parameters and studies of new synthesis methods, allowing further adjustment in the formation of these materials. In this context, were synthesized ZSM-12 (Si/Al = 50), AlMCM-41 (Si/Al = 100) AlMCM-48 (Si/Al = 100), by methods of synthesis have been explored in the literature and proposed methods synthesis for the formation of micro-mesoporous materials of the type ZSM-12/MCM-41 and ZSM-12/MCM-48. The materials ZSM-12, AlMCM-41 and AlMCM-48 were subjected to ion exchange process to obtain the acid form, HZSM-12, HAlMCM-41 and HAlMCM-48. Then all of the synthesized materials were impregnated with lanthanum oxide. The catalysts were characterized by physicochemical techniques. The X-ray diffraction patterns of the synthesized samples showed characteristic peaks of ZSM-12, MCM-41 and MCM-48 before and after impregnation with the lanthanum oxide. The absorption spectra in the infrared showed bands relating to links of each structure. The materials presented adsorption and desorption isotherms of N2 type I, to HZSM-12 and type IV for HAlMCM-41, HAlMCM-48, HZSM-12/MCM-41 and HZSM-12/MCM- 48 materials. The hybrid type HZSM-12/MCM-41 and HZSM-12/MCM-48 exhibited high values of surface areas (in the range of 689-1304 m2 g-1) which confirmed the formation of mesopores as well as pore diameters in the range of 3.6 nm. The microstructural analysis of the samples revealed the presence of the microporous, mesoporous, micro-mesoporous phases and lanthanum oxide before and after the impregnation process and thermogravimetric curves determined to dehydration temperatures of the materials and their thermal stability.