Reaction experiments were also conducted in identical conditions in the presence of catalysts recovered after the reaction. The results indicated that sustainable activity could be achieved in the presence of these spent catalysts with activity losses around 10%. Evaluation of characterization analyses conducted with fresh and spent catalysts showed that the activity loss of SBA15-S catalysts had merely been due to STA leaching, whereas deformation of pore structure had occurred in MCM-41-S catalysts. |