Mesoporous Al-MCM-41 (Si/Al = 20) molecular sieve was synthesized hydrothermally and characterized by X-ray diffraction (XRD), nitrogen-sorption studies and Al-27 and Si-29 MAS-NMR spectroscopies. 10, 20 and 40w1% phosphotungstic acid (PW) (H3PW12O40) were supported on Al-MCM-41 and the resulting catalysts were characterized by XRD, FT-IR, nitrogen-sorption, DRIFT, H-1 and P-31 MAS-NMR and DRS UV-vis spectral techniques. H-1 MAS-NMR spectra of PW/Al-MCM-41 revealed leveling of the acidity of PW protons to Al-MCM-41. Their catalytic activities were evaluated in the esterification of succinic anhydride with ethanol in the temperature between 60 and 120 degrees C. Monoethyl succinate (MES) and diethyl succinate (DES) were obtained as products. The effects of alcohol/anhydride molar ratio and temperature were studied. Unsymmetrical alcoholysis of succinic anhydride with methanol and 1-butanol vias also carried out successfully. (c) 2005 Elsevier B.V. All rights reserved.