Assessment of dominant factors affecting liquid phase hydroisomerization on bifunctional zeolites

• Published in: Applied catalysis. A, General Vol. 349; no. 1; pp. 29 - 39
• Main Authors: Fúnez, A., Thybaut, J.W., Marin, G.B., Sánchez, P., De Lucas, A., Valverde, J.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 31.10.2008; Elsevier
• Subjects: Beta; Catalysis; Chemistry; Colloidal state and disperse state; Exact sciences and technology; Experimental investigation; General and physical chemistry; Hydroisomerization; Ion-exchange; Kinetic model; Liquid phase conditions; Mordenite; n-Octane; Porous materials; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; USY; Zeolite; Zeolites: preparations and properties; Kinetic model; Liquid phase conditions; n-Octane; Mordenite; Hydroisomerization; USY; Zeolite; Experimental investigation; Beta; Octane; Experimental data; Expérimental investigation; Liquid phase; Conversion; Dispersion; Composite material; Molecular sieve; Operating conditions; Isomer; Geometry; Heterogeneous catalysis; Pore size; Acids; Bêta; Activation energy; Catalyst
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2008.07.009

Liquid phase n-octane hydroisomerization was investigated over a series of zeolites containing 1 wt% Pt. PtBETA was the most active catalyst followed by PtMOR and PtUSY. The isomer yields on PtMOR were somewhat lower than on PtBETA and PtUSY. A kinetic model fitted adequately the experimental data on PtBETA and PtUSY, while more dispersion was observed with catalyst PtMOR. These modelling results were related to pore sizes and geometry and average acid strength. ▪ The hydroisomerization of n-octane in the liquid phase was investigated over beta, USY and mordenite zeolites loaded with 1 wt% Pt in a stirred semi-batch microautoclave. The total pressure ranged form 5 to 9 MPa and the temperature from 523 to 563 K with an initial catalyst/ n-octane ratio of 7   g catalyst /mo l n - C 8 . PtBETA was the most active catalyst at all operating conditions, followed by PtMOR and PtUSY. The isomer yields on PtMOR were somewhat lower than on PtBETA and PtUSY. Increasing the total pressure always resulted in a decrease in the n-octane conversion, which is indicative of so-called ideal hydroisomerization. The n-octane hydroisomerization experiments were simulated with a kinetic model based on a parallel/consecutive reaction scheme involving reversible mono- and multibranching and irreversible cracking from mono- as well as multibranched isomers. The model fitted adequately the experimental data on PtBETA and PtUSY. However, more dispersion was observed with catalyst PtMOR. The ratio of the composite rate coefficients for cracking to that for monobranching was significantly higher on PtMOR than on PtUSY and PtBETA. The composite activation energy for monobranching was 20 kJ mol −1 higher on USY if compared to that of mordenite and beta. These modelling results were related to pore sizes and geometry and average acid strength.