Preparation and physicochemical and catalytic properties of micro-mesoporous catalysts based on faujasite

Resumo

Micro-mesoporous samples of materials based on faujasite Y (SiO₂/Al₂O₃ = 85) have been obtained by modifying in a solution containing either a base or a base and a surfactant. The influence of the composition of the alkaline solution (NaOH, NH₄OH, (CH₃)₄NOH) and the presence of the surfactant cetyltrimethylammonium bromide (CTAB) in the system have been studied. It has been shown that it is reasonable to prepare faujasite-based micro-mesoporous materials on by the action of the organic base tetramethylammonium hydroxide (TMAOH). It has been found that the extent of desilylation, which determines the chemical composition and share of mesopores in materials, depends on the TMAOH concentration and the presence of surfactant. In the presence of CTAB mesopores with a diameter of about 40 Å are formed, the share of which can be controlled by treatment conditions. The resulting materials have been examined in the reaction of cyclohexanone oxime conversion to ε-caprolactam. It has been found that materials with the combined micro-mesoporous structure show higher stability among the samples with similar acidic properties but different porosity characteristics.