Aromatization of propene and n-butene over H-galloaluminosilicate (ZSM-5 type) zeolite

• Published in: Applied catalysis. A, General Vol. 231; no. 1; pp. 243 - 251
• Main Authors: Choudhary, Vasant R., Panjala, Devadas, Banerjee, Subhabrata
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10.05.2002; Elsevier
• Subjects: Aromatization of n-butene; Aromatization of propene; Catalysis; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; H-galloaluminosilicate (ZSM-5 type) zeolite; Reaction path for olefin aromatization; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Aromatization of n-butene; Reaction path for olefin aromatization; Aromatization of propene; H-galloaluminosilicate (ZSM-5 type) zeolite; Catalytic reaction; Gallium Aluminosilicates; Hydrocarbon; Zeolite; Experimental study; Molecular sieve; Heterogeneous catalysis; Aromatization; Propene; Preparation; Kinetic parameter; Catalyst activity; Butene; Ethylenic compound
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/S0926-860X(02)00061-3

Aromatization of propene and n-butene (at 400 °C and atmospheric pressure) over H-GaAlMFI zeolite (bulk Si/Al=37.5, bulk Si/Ga=24.3, framework (FW) Si/Al=40.3, FW Si/Ga=49.9, non-FW Ga=0.32 mmol g −1, crystal size=5.5±1.5 μm) having high acidity (pyridine chemisorbed at 400 °C=0.46 mmol g −1) has been investigated at different space velocities (3100–58,100 cm 3 g −1 h −1). The catalyst was found to have a high olefin aromatization activity and high aromatics selectivity, these are attributed to the presence of a large number of both non-framework Ga-species and protonic acid sites. The product selectivity and distribution were strongly influenced by the space velocity. The distributions of aromatics and xylene isomers are found to be similar for the aromatization of both propene and n-butene, but that of aliphatic hydrocarbons differed in the two cases. The propene and n-butene aromatization reactions involve both the protonic acid sites mediated hydride transfer reactions and the direct dehydrogenation reactions over non-framework Ga-species, probably in combination with the zeolitic protons. A reaction path for the propene/ n-butene aromatization is proposed.