Thermal analysis of `exploding' [n]rotanes

Abstract The thermal decomposition behavior of four different perspirocyclopropanated macrocyclic oligodiacetylenes, also known as `exploding' [ n ]rotanes, was characterized by DSC and EGA. The influence of ring size, number of diethynylcyclopropane segments and permethylation of the cyclopropyl groups on the thermal decomposition is shown. The heat of decomposition surpasses that of conventional explosives. For example, the heat of explosion of [6]rotane calculated by adiabatic thermodynamics is 3426±87 kJ/mol. The kinetic constants of the EGA profile of permethylated [6]rotane are reaction order n =1, activation energy Δ E a =135.3±6.1 kJ/mol and preexponential factor log Z =12.82±1.04. Besides quantities of soot, acetylene, methane and ethene were recorded as decomposition products, and tetramethylethene for permethylated [6]rotane, indicating that the first step in the thermal decomposition of `exploding' [ n ]rotanes is the cleavage of the cyclopropane bond.