| 초록 |
Two types of ZSM-5 catalysts with different mesoporosity were synthesized by using a structural directing agent of tetra-n-butylphosphonium hydroxide and controlling the molar compositions of ethanol and water in the synthetic precursor. The synthesized ZSM-5 catalysts were formed through interconnection of very thin pillars or lamellae; (1) H_30 (high mesoporosity) and L_30 (low mesoporosity). With pyridined-based acid titration results, it is revealed that internal Brønsted acid sites of H_30 were similar to those of C_75 (Si/Al: ~75) but H_30 had much more external Brønsted acid sites than C_75. In methanol to hydrocarbon reaction (MTH), compared with C_75, higher propene to ethene ratio could be obtained with H_30 because of its short diffusional length. Whereas very poor MTH performance was shown with L_30 due to the lack of internal Brønsted acid sites. Moreover, by dopping the ceria to H_30, higher propene to ethene ratio and stability in MTH reaction were obtained. |
