Facile activation of dihydrogen by long-lived carbonium ions on silica–alumina catalysts. An example of a simple [2 + 2]-type reaction

Abstract

Silica–alumina catalyses the gas phase hydrogenation of norbornadiene and 1-chloroadamantane at the surprisingly moderate temperature of 90 °C showing that when the carbonium ion intermediates are long-lived the R⁺⋯ O^–—surface species reacts with dihydrogen in a [2 + 2]-type reaction, and does so far more readily than the corresponding H⁺⋯ O^–—cation–anion pair.