Urethane reaction kinetics of butanediols catalyzed by Zr(acac)_4

摘要

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.