Urethane reaction kinetics of butanediols catalyzed by Zr(acac)4

The urethane reaction of isocyanate was carried out with zirconium acetyl acetonate (Zr(acac)₄) as catalyst. 1,2‐Butanediol and 1,4‐butanediol were used as model compounds to investigate the reaction kinetics. It was shown that hydroxyl groups in 1,2‐butanediol appeared to have different reaction rate when reacting with phenyl isocyanate, which was labeled as k_fast and k_slow. It was very surprising that the reaction rate of 1,4‐butanediol (k_con) was very similar to the value of k_slow at the same temperature although there is only primary hydroxyl group in its molecule. Furthermore, activation energy (E_a), activation enthalpy (ΔH), and activation entropy (ΔS) for the reaction were calculated out, from which some catalytic properties of Zr(acac)₄ were revealed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013