Catalytic performance of strong acid catalyst: Methyl modified SBA-15 loaded perfluorinated sulfonic acid obtained by the waste perfluorinated sulfonic acid ion exchange membrane

Highlights: • Mesoporous SBA-15 materials are modified by the trimethylchlorosilane. • Solid acid catalysts are prepared by perfluorinated sulfonic acid impregnation. • Activities of catalysts are evaluated by alkylation of phenol with tert-butanol. • The resulting catalysts exhibit good catalytic performance. • The methyl group loaded on catalyst surface can retard deactivation of catalyst. - Abstract: Mesoporous molecular sieve (SBA-15) was modified using the trimethylchlorosilane as functional agent and the silylation SBA-15 mesoporous material was prepared in this work. The alcohol solution of perfluorinated sulfonic acid dissolved from the waste perfluorinated sulfonic acid ion exchange membrane (PFSIEM) was loaded onto the resulting mesoporous material by the impregnation method and their physicochemical properties were characterized by FT-IR, N₂-physisorption, XRD, TG-DSC and TEM. The catalytic activities of these synthesized solid acid catalysts were evaluated by alkylation of phenol with tert-butyl alcohol. The influence of reaction temperature, weight hour space velocity (WHSV) and reaction time on the phenol conversion and product selectivity were assessed by means of a series of experiments. The results showed that with the increase of the active component of the catalyst, these catalysts still remained good mesoporous structure, but the mesoporous ordering decreased to some extent. These catalysts exhibited good catalytic performance for the alkylation of phenol with tert-butanol. The maximum phenol conversion of 89.3% with 70.9% selectivity to 4-t-butyl phenol (4-TBP) was achieved at 120 °C and the WHSV is 4 h⁻¹. The methyl group was loaded on the surface of the catalyst by trimethylchlorosilane. This is beneficial to retard the deactivation of the catalyst.