| Titre : | Adsorption/desorption studies of 224-trimethylpentane in β-Zeolite and mesoporous materials using a tapered element oscillating microbalance (TEOM) (2010) |
| Auteurs : | Kening Gong, Auteur ; Tiepan Shi, Auteur ; Palghat A. Ramachandran, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 48 N° 21, Novembre 2009) |
| Article en page(s) : | pp. 9490–9497 |
| Note générale : | Chemical engineering |
| Langues : | Anglais |
| Tags : | 224-Trimethylpentane β ; -Zeolite Mesoporous materials |
| Résumé : | The facile desorption of C8 and heavier products from solid acid alkylation catalysts is essential to thwart catalyst deactivation by fouling. To better understand this phenomenon, a tapered element oscillating microbalance (TEOM) was employed to investigate the adsorption/desorption characteristics of 224-trimethylpentane (224-TMP), a proxy C8 alkylate product, on β-zeolite and mesoporous materials (T = 298−473 K, P224-TMP = 0−0.3 bar). It is found that the 224-TMP desorption rates from saturated β-zeolite (by helium purging) are characterized by a rapid initial “burst” of 224-TMP followed by a rather long desorption phase. Complementary experimental and modeling investigations using pelletized β-zeolites of known sizes indicate that the adsorption rate and initial desorption (during the burst phase) rate of 224-TMP are controlled by meso-/macropore diffusion resistance external to the β-zeolite crystals and that the long transient could be due to pore diffusion resistance within the β-zeolite crystals. In contrast, mesoporous silica materials provide facile pore accessibility for large alkylate molecules such as 224-TMP, as evidenced by complete desorption of 224-TMP even at mild temperatures. These insights provide guidance for rational engineering of stable solid acid alkylation catalysts. |
| En ligne : | http://pubs.acs.org/doi/abs/10.1021/ie900334g |
