Thermal unimolecular decomposition of 1,1,3,3-tetramethylcyclobutane

Abstract

The thermal decomposition of 1,1,3,3-tetramethylcyclobutane has been investigated in the range 410–522°. In an aged reaction vessel the decomposition is homogeneous and first order and the primary product is isobutene. Rate constants, which were independent of pressure in the range 7–50 torr, fit the Arrhenius equation, k= 10^16·31 exp(–65,160 cal./RT) sec.^–1. Some decomposition of the isobutene occurs at the reaction temperatures but this is considerably slower than the rate of the cyclobutane decomposition. The results obtained are compared with those for other alkylcyclobutanes and the nature of the transition complex is discussed.