In Situ FT-IR Studies of the Zirconium (IV) Acetylacetonate Catalyzed Urethane Reaction of Butanediols

Abstract

A comparative kinetic study of the urethane reactions of phenyl isocyanate and 1,2-, 1,3-, and 1,4-butanediol was carried out in dichloromethane solution with zirconium (IV) acetylacetonate as catalyst. In situ FT-IR was used to follow the kinetics of the reactions at a constant temperature of 15°–30°C. The rate constants for the reaction of the primary hydroxyl group and the secondary hydroxyl group were calculated as k _prim and k _sec, respectively. Analysis of the second-order rate constants of these systems indicated that k _prim follows 1,2-butanediol >1,3-butanediol >1,4-butanediol. The ratio of k _prim/k _sec in 1,2-butanediol was the highest and the order followed was the same as with the reaction rate. Activation energies and Eyring parameters were also determined for the urethane reaction of butanediols.

Keywords:

• Butanediol
• Catalyst
• In situ FT-IR
• Polyurethane

Acknowledgments

The authors are grateful for the financial support from the National Natural Science Foundation committee of China (No. 21176147).