Shaping of Mesoporous AlSBA-15 as Cylindrical Nano Reactor for Tertiary Butylation of Phenol

Mesoporous AlSBA-15 with different n _Si/n _Al ratios (45, 136 and 215) in the powder (P) form were synthesized by hydrothermal technique. The powder materials were shaped into cylindrical extrudates (Ex) by compounding with additives such as bentonite (binder) and methylcellulose (plasticizer). The AlSBA-15 materials were characterized by XRD, N₂ adsorption, AAS, ²⁷Al MAS-NMR and thermogravimetric analysis. The orderly growth of AlSBA-15 is evidenced by its XRD patterns. The surface area and pore volume of AlSBA-15 catalysts were around 950 m²/g and 1.3 cm³/g respectively. A decrease in surface area and pore volume were observed for AlSBA-15 (Ex) materials in comparison to AlSBA-15 (P) materials. This may be due to partial blocking of pore entry and surface area coverage of additives during the shaping of extrudates. Vapor phase alkylation of phenol with tert-butanol was carried out over AlSBA-15 (P) and AlSBA-15 (Ex) catalysts and the results revealed that both powder and extrudate samples showed similar activity for phenol conversion. The activity of AlSBA-15 catalysts follows the order: AlSBA-15 (45) > AlSBA-15 (136) > AlSBA-15 (215) for both powder and extrudate forms. The major products were 2-tert-butylphenol (2-TBP), 4-tert-butylphenol (4-TBP) and 2,4-di-tert-butylphenol (2,4-DTBP). The selectivity to para product is much higher than other products. The catalyst exhibited steady conversion, and deactivation by coke formation of the catalyst is much reduced in AlSBA-15 materials.