Comparison of the Acidity of Heteropolyacids Encapsulated in or Impregnated on SBA-15Teresa Pinto, Kai Szeto, Nesrine Oueslati, Nadine Essayem, Véronique Dufaud and Frédéric LefebvreOil Gas Sci. Technol. – Rev. IFP Energies nouvelles, 71 2 (2016) 25DOI: https://doi.org/10.2516/ogst/2016005