Synthesis of solid acid catalysts for esterification with the assistance of elevated pressure

Acidic catalysts dedicated for esterification processes were prepared by immobilization of (3-mercaptopropyl) trimethoxysilane (MPTMS) on mesoporous silica and niobiosilicate material using a new methodology, i.e. solvothermal technique with increased pressure. The structure and surface properties of the samples obtained were examined using N-2 adsorption/desorption, XRD, TEM, /CPS and elemental analysis. The impact of modification technique as well as the presence of niobium in the sample on the acidity of final materials was investigated. It was found that the application of external pressure during the solvothermal modification of mesoporous silica with MPTMS allows obtaining materials with a greater number of acidic sites. These samples showed a high activity and stability in esterification of acetic and propionic acid with n-butanol and n-hexanol.