Shape-selective isopropylation of biphenyl over H-mordenites

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

“…On the other hands, the internal acid sites are not significantly deactivated by the adsorbed propene due to the steric limitation of the channels, and effectively work as the catalytic sites for the isopropylation. Similar deactivation at the external acid sites by propene adsorption was observed in the isopropylation of BP over MOR [6,7,[30][31][32].…”

“…In addition, we note that no significant isomerization of 1-IPN to 2-IPN and 2,6-DIPN to 2,7-DIPN occurred during the isopropylation of NP over MOR at the conditions. The similar features of the catalysis were observed in the isopropylation of BP over MOR in our previous works [3,4,6,7,30,31] We discuss, in the next sections, where and how the selective formation of the least bulky 2,6-DIPN occurs in the isopropylation of NP from the aspects of the selectivities for DIPN isomers in bulk and encapsulated DIPN isomers, and attempt to clarify the roles of internal and external acid sites of H-MOR. Figure M a n u s c r i p t…”

“…We have previously proposed that the encapsulated products are "finger prints of the catalysis" for the explanation of the catalysis in zeolite channels in the isopropylation of NP and BP [4,6,7,12,31,32]. In this paper, we describe the relationships between bulk and encapsulated DIPN isomers from low to high conversions under various reaction parameters in the isopropylation of NP with propene over MOR, and discuss where and how the shape-selective catalysis occurs.…”

“…Some of the physicochemical properties of MOR have been described elsewhere [12,31]. NP was purchased from Aldrich Australia, Sydney, NSW, Australia.…”

“…We observed the isomerization of 4,4'-diisopropylbiphenyl (4,4'-DIPB) in the isopropylation of BP over MOR [3,4,6,7,31,32]. The isopropylation of BP was highly selective for the formation of 4,4'-DIPB at moderate reaction conditions; however, the decrease in the selectivities for 4,4'-DIPB occurred at reaction conditions, such as high temperature, low propene pressure, and/or large amount of catalyst, resulting in the increase in the selectivities for bulky and thermodynamically stable 3,4'-and 3,3'-DIPB.…”