K. Y. Koltunov, S. Walspurger, J. Sommer
Nov 1, 2004
Citations
0
Influential Citations
13
Citations
Journal
Catalysis Letters
Abstract
Reactions of benzaldehyde (1) and related compounds–3-pyridinecarboxaldehyde (9) and acetophenone with benzene, chlorobenzene, o-dichlorobenzene and cyclohexane in the presence of superacids or H-form zeolite, HUSY were (re)investigated. In accordance with previous data, 1 condenses with benzene in triflic acid (CF3SO3H) as well as on HUSY to give triphenylmethane. At elevated temperature 1 also reacts with chlorobenzene but is inert towards o-dichlorobenzene. While 1 does not react with cyclohexane in CF3SO3H−SbF5, 9 undergoes readily selective ionic hydrogenation to give 3-pyridilcarbinol (14). In the presence of excess of AlCl3, however, as well as on HUSY, 1 reacts with cyclohexane to produce toluene. The mechanistic aspects of these reactions are discussed. Opposed to earlier, repeatedly cited suggestions that the reactivity of 1 involves, as in case of 9, superelectrophilic diprotonated species, we show that a monocationic intermediate is the best rationale for these results