Al-MCM-41 modified with carbonaceous deposits: characterisation by nitrogen adsorption measurements

Abstract

Aluminosilicate MCM-41 samples in the as-prepared form and modified by deposition of carbonaceous compounds formed during conversion of cyclohexene were investigated by nitrogen adsorption. The amount of the deposits decreases with the reaction temperature and increases with the quantity of aluminium incorporated into the materials. The formation of coke occurs primarily in the aluminium-rich pores. The modification leads to a lowering of adsorption capacity, surface area, pore volume and relative pressure corresponding to the adsorption isotherm step that reflects the capillary condensation. The nitrogen adsorption measurements appeared to be a useful tool for characterisation of structural and surface properties of both the original and the novel surface-modified porous materials.