The isopropylation of naphthalene with propene over H-mordenite: The catalysis at the internal and external acid sites

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 2014-12, Vol.395, p.543-552
• Main Authors: Sugi, Yoshihiro, Anand, Chokkalingam, Subramaniam, Vishnu Priya, Stalin, Joseph, Choy, Jin-Ho, Cha, Wang Soo, Elzatahry, Ahmed A., Tamada, Hiroshi, Komura, Kenichi, Vinu, Ajayan
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Exact sciences and technology; External acid sites; General and physical chemistry; Ion-exchange; Isomerization; Mordenite; Naphthalene; Shape-selective catalysis; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zeolites: preparations and properties
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2014.08.035

•Mordenite has a shape-selective nature for the isopropylation of naphthalene.•Selective formation of 2,6-diisopropylnaphthalene (2,6-DIPN) inside the channels.•Decrease in selectivities for 2,6-DIPN by the isomerization at external acid sites. The isopropylation of naphthalene (NP) with propene over H-Mordenite (MOR) was studied under a wide range of reaction parameters: temperature, propene pressure, period, and NP/MOR ratio. Selective formation of 2,6-diisopropylnaphthalene (2,6-DIPN) was observed at reaction conditions, such as at low reaction temperature, under high propene pressure, and/or with high NP/MOR ratio. However, the decrease in the selectivities for 2,6-DIPN was observed at reaction conditions such as at high temperature, under low propene pressure, and/or with low NP/MOR ratio. The selectivities for 2,6-DIPN in the encapsulated products were remained high and constant under all reaction conditions. These results indicate that the selective formation of 2,6-DIPN occurs through the least bulky transition state due to the exclusion of the bulky isomers by the MOR channels. The decrease in the selectivities for 2,6-DIPN are due to the isomerization of 2,6-DIPN to 2,7-DIPN at the external acid sites, directing towards thermodynamic equilibrium of DIPN isomers.