In several recent papers [15] we have shown that cyclic organic species are part of the active sites for methanol-toolefin (MTO) catalysis on microporous solid acids [6,7]. On zeolite HZSM-5 these reaction centers are either methylsubstituted cyclopentenyl carbenium ions or methylbenzenes [2]. On the silico-aluminophosphate acid catalyst HSAPO-34 [7], the reaction centers are methylbenzenemolecules [3,5], and we cannot rule out the possibility that other types of arenes, e.g., methylnaphthalenes, could also be reaction centers. HSAPO-34 has the CHA topology (its 1 nm cages are interconnected through 0.37 nm windows), and aromatic molecules, even benzene, once formed cannot escape SPEX6970EFM 冷凍研磨機(jī)