Alumina-anchored cobalt porphine catalysts for the conversion of quadricyclane to norbornadiene

Methods are described for the preparation of cobalt(II) deuteroporphyrin and cobalt(II) tetrakis(p-sulfonatophenyl)porphine anchored on alumina beads coated with polyaminesulfone-A. Wavelength dispersive X-ray microanalysis showed that the cobalt(II) porphine distributes within the catalyst outer surface layer of ca. 100 μm depth. The catalysts are highly active for the cycloreversion of quadricyclane to norbornadiene. A detailed kinetics of the isomerization using an isothermal recycle reactor gave a rate expression of Langmuir–Hinshelwood type. The catalysts gradually lose their activity, which can be regenerated completely by heating the catalysts at 200 °C in vacuo.