Physico—chemical characterization of pentasil type materials

An investigation into factors which influence the formation of p-cresol in the methanol alkylation of phenol over MCM-22 and ZSM-5

“…This has also been observed in hydrocarbon reactions over zeolites, namely isomerization [24][25][26][27], alkylation [28] and cracking [25,29]. The EFAl species formed in the steaming process [30], as is well known, usually migrate to the external surface of the crystallites [31]. These species will obstruct the narrow pores of MCM-22, thus increasing the diffusional resistance in the pores and thereby favouring the formation of the ''slimmest'' isomer, namely p-cresol.…”

The Influence of the External Acidity of H-ZSM-5 on Its Shape Selective Properties in the Disproportionation of Ethylbenzene

“…Since the crystals used were all synthesized using TPA as the template, enrichment of Al is to be expected. It can amount to a factor of 5 or more (16,29,30) which, together with the presence of surface roughness and cracks, explains the high concentration of acid sites measured by 2,6-dimethylpyridine.…”

3D Raman Spectroscopy of Large Zeolite ZSM‐5 Crystals

“…Here, we have studied the effect of steaming on the integrity of the structure of large zeolite ZSM‐5 crystals with Raman microscopy. It is known from previous studies that the large zeolite ZSM‐5 crystals used in this study (and synthesized using a TPA + template) have Al enrichment on the crystal edges and the outer surface . In this work, parent (non‐steamed) zeolite ZSM‐5 crystals (further denoted as P‐ZSM‐5) are compared with two sets of steamed ZSM‐5 crystals that are either mildly treated at 500 °C (further denoted as MT‐ZSM‐5) or severely treated crystals at 700 °C (further denoted as ST‐ZSM‐5).…”

“…Here, we have studied the effect of steaming on the integrity of the structure of large zeolite ZSM-5 crystals with Raman microscopy.I ti sk nown from previouss tudiest hat the large zeolite ZSM-5 crystalsu sed in this study (and synthesized using aT PA + template) have Al enrichment on the crystal edges and the outer surface. [44][45][46][47][48] In this work, parent( nonsteamed) zeolite ZSM-5 crystals( further denoted as P-ZSM-5) are compared with two sets of steamed ZSM-5 crystals that are either mildly treated at 500 8C( further denoted as MT-ZSM-5) or severelyt reated crystals at 700 8C( further denoted as ST-ZSM-5). Previous studies with scanning electron microscopy (SEM) and atomic force microscopy (AFM) have demonstrated that there is no significant change in the overall morphology of the zeolite ZSM-5 crystal upon steaming under the abovewritten conditions.…”