Selective rhodium-containing zeolite catalysts for cyclodimerization of bicyclo[2.2.1]hepta-2,5-diene

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 1996, Vol.106 (1), p.159-168
• Main Authors: Gol'dshleger, Nataliya F., Azbel', Boris I., Isakov, Yakov I., Shpiro, Efim S., Minachev, Khabib M.
• Format: Article
• Language: English
• Subjects: Cyclodimerization; Norbornadiene; Rhodium; Zeolite
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/1381-1169(95)00255-3

It has been shown that norbornadiene (NBD) is dimerized in the presence of rhodium zeolite systems forming hexacyclodimers, exo-endo- and endo-endo-hexacyclo[9.2.1.0 4.6.0 3.8.0 2.10.0 5.9]tetradec-12-enes preferentially. The effect of the structure, preparation procedure and pretreatment of the catalysts on their activity and selectivity in norbornadiene cyclodimerization and the change in the rhodium electronic state in the course of the reaction have been studied. Alcohols (nortricyclan-3-ol and norbornen-5-ol) and ethers (3-tricyclo[2.2.1.0 2.6]-heptyloxy-3′)bicyclo[2.2.1]hept-5-ene and 3,3′-oxydinortricyclane) as well as norbornadiene cyclodimers were formed when the catalysts containing both the rhodium and acid sites were pretreated with retaining adsorbed water. Interaction of the Rh Na-ZSM-5 catalyst with H 2 or norbornadiene under mild conditions (130–150°C) leads to the stabilization of a significant portion of rhodium in the form of Rh(I), and apparently a complex formed is like that of [NBD-Rh(I)]-O zeol. Norbornadiene cyclodimerization takes place with the participation of the active centres localized on the outside surface of the zeolite crystals.