Synthesis of a large pore phenyl-modified mesoporous silica and its characterization by nitrogen and benzene sorption

Abstract

Phenyl-modified porous silicas have been synthesized at room temperature by the co-condensation of a siloxane and an organosiloxane in the presence of a surfactant. Mesitylene was employed as a pore swelling agent to produce a mesostructured material. The product has been characterized by powder XRD, nitrogen sorption at 77 K and benzene sorption at 293 K. Powder XRD data yielded ad₁₀₀ spacing of 52.0 Å for the as-synthesized material and 49.5 Å after template removal. Nitrogen sorption is characterized by a type IV isotherm indicating mesoporosity with a BET specific surface area of 942 m² g^–1 and a Gurvitsch pore volume of 0.67 cm³ g^–1 . Benzene sorption also produced a type IV isotherm with a BET specific surface area of 1051±50 m² g^–1 and a Gurvitsch pore volume of 0.75 cm³ g^–1 . The discrepancy in the total pore volume values may be due to the structure of the adsorbed benzene. Samples produced in the presence of tetradecane or in the absence of any pore swelling agent have pores in the microporous range.