Kinetics and Mechanism of Carbamate Reaction of 4-Hydroxybenzyl Alcohol with Phenyl Isocyanate

Abstract

The reaction of 4-hydroxybenzyl alcohol with phenyl isocyanate in 1,4-dioxane was investigated, using in-situ FT-IR as the main tool. It was found that there was a remarkable induction phase in the reaction. Further, the reaction between isocyanate and the two types of hydroxyl groups in 4-hydroxybenzyl alcohol falls into two phases, with the phenolic hydroxyl being unexpectedly more reactive than the alcoholic hydroxyl. The reaction kinetics were also studied, and the activation energies were calculated to be 46.4 kJ mol−1, 35.2 kJ mol−1 and 41.5 kJ mol−1 for the induction, phenolic and alcoholic phases, respectively.