Mechanistic and kinetic studies of the copolymerization of citronellol and acrylonitrile initiated by benzoylperoxide

Abstract

The radical copolymerization of citronellol with acrylonitrile (AN) in xylene at 75 ± 0.1°C for 1 h in the presence of benzoylperoxide (BPO) follows ideal kinetics with bimolecular termination and results in the formation of an alternating copolymer as evidenced from the values of reactivity ratios as r ₁ (acrylonitrile) = 0.0062 and r ₂ (citronellol) = 0.0003, which have been calculated using the Kelen–Tüdos method. The overall activation energy is computed as 30 kJ/mol. The IR spectrum of the copolymer shows the presence of brands at 3500 cm^-1, assigned to the alcoholic group, and 2240 cm^-1, assigned to the cyanide group. The ¹H-NMR spectrum of the copolymer shows peaks between 7 and 7.7 δ, assigned to the alcoholic group of citronellol. The nitrogen percentage was evaluated by elemental analysis. The Alfrey–Price Q–e parameters for citronellol has been calculated as -0.46 and 0.97. The copolymer is highly thermally stable and has a glass transition temperature (T _g) of 102°C, as evaluated by Differential Scanning Calorimetry (DSC) studies. The mechanism has also been elucidated.

Keywords:

• Citronellol
• acrylonitrile
• copolymerization
• reactivity ratios.