The influence of template extraction methods on the structure and physico-chemical properties of Al-MCM-41 molecular sieves has been investigated. Up to 78% of template in Al-MCM-41 could be removed either by extraction with ordinary solvents or methanol-modified supercritical CO2, Complete template removal was achieved by calcination. Both, solvent and supercritical fluid extraction media influenced the structure, texture and acid properties of the resulting Al-MCM-41 materials and, consequently, their catalytic activity for the Friedel-Crafts acylation of 2-methoxynaphthalene. (c) 2005 Elsevier B.V. All rights reserved.