Kinetics of thermoinitiated oligomerization of 3,3′-(2,4,6-triethyl-1,3-phenylene)bis(5-methyl-1,2,4-oxadiazole)

The crystal structure of 3,3′-(2,4,6-triethyl-1,3-phenylene)bis(5-methyl-1,2,4-oxadiazole), which models the cross-linking fragment of polynitriles by benzodinitrile oxides, was determined by X-ray diffraction analysis. The kinetic regularities of its thermoinitiated oligomerization were studied by isothermal calorimetry and spectrophotometry. The process proceeds with self-acceleration, and the Arrhenius dependences of the initial and maximum reaction rates were determined. The reaction accelaration is determined by an increase in the viscosity of the reaction medium. Possible mechanisms were proposed for oligomerization.