Isomerization of n-butane to isobutane over Pt-SAPO-5, SAPO-5, Pt-H-mordenite and H-mordenite catalysts

• Published in: Catalysis today 2005-02, Vol.100 (3), p.355-361
• Main Authors: Kumar, Narendra, Villegas, Jose Ignacio, Salmi, Tapio, Murzin, Dmitry Yu, Heikkilä, Teemu
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Ion-exchange; Isomerization; Mordenite; n-Butane; Pt-mordenite; Pt-SAPO-5; SAPO-5; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zeolites: preparations and properties
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2004.10.023

Aluminium sulphate, sodium aluminate, aluminium oxide and pseudo-boehmite were used as sources of aluminium in the synthesis of SAPO-5. The samples were characterized using XRD, SEM, XRF, FTIR and nitrogen adsorption. The formation of SAPO-5 phase, morphology, surface area and catalytic properties were found to be influenced by the source of aluminium used in the synthesis. The sample synthesized using pseudo-boehmite as a source of aluminium showed most phase pure silicoaluminophosphate, whereas syntheses using aluminium phosphate or sodium aluminate only formed quartz and berlinite. The FT-IR spectra exhibited the presence of Brønsted and Lewis acid sites in the Pt-SAPO-5, SAPO-5, Pt-H-mordenite and H-mordenite catalysts. Modification of SAPO-5 and mordenite by Pt impregnation did not influence the structures of these catalytic materials. The Pt-H-mordenite and H-mordenite catalysts with stronger Brønsted acidity exhibited higher conversion of n-butane and yield to isobutane than Pt-SAPO-5 and SAPO-5 catalysts with weak acid sites. Introduction of Pt in SAPO-5 and mordenite played a positive role in the isomerization of n-butane to isobutane.