The adsorption of H3PW12O40 from water and organic solvents (acetone and acetonitrile) by carbon mesoporous materials (Sibunit and fluorinated Sibunit (F-Sibunit)) was studied. The concentration of Bronsted acidic sites in H3PW12O40 and No H3PW12O40/F-Sibunit was determined from ESR studies of the stable nitroxyl radical (4-hydroxy-2,2',6,6'-tetramethylpyperidin-N-oxyl (TEMPOL)) adsorbed from hexane. For H3PW12O40 and 8% H3PW12O40/F-Sibunit, the concentration was equal to 4 and 12 mumol g(-1), respectively. A correlation between the rate constant of cyclohexene dimerisation of in the hexane solution and the strength of HPA-support interaction was determined. (C) 2004 Elsevier B.V. All rights reserved.