Intramolecular insertion of isobutylidene in the vacuum ultra-violet photolysis of isobutane

Abstract

The direct photolysis of isobutane was carried out at the Xe resonance line (1470 Å) at 25°C over the pressure range 5.3–410 torr, with and without added nitrogen. Evidence was found for the intramolecular insertion of isobutylidene resulting from the carbene elimination of H₂. From the C₄ product distribution at the highest pressure it was deduced that the ratio of isomerization of isobutylidene to intramolecular cyclization is 19 : 1.