Thermal Condensation in Solid State of N-Hydroxyalkyl-2-imidazolidinone

Abstract

Abstract N-(1-Hydroxyalkyl)-2-imidazolidinones (1) were prepared by a reaction of 2-imidazolidinone with form-, acet-, propion-, and butyraldehyde. In all of these reactions, 1 were unstable and moisture-sensitive substances. The pyrolysis reaction of 1 was found to be a thermal decomposition via a condensation reaction stage after a molten state. The condensation stage obeyed 1/2- and the first-order kinetics. The kinetic data regarding the condensation reaction were evaluated by analyses of the dependences of the area of isothermal DSC curves upon the reaction time. It may be concluded that the difference provided by the reaction order and the activation parameters were caused by the number of the hydrogen atoms on the β-carbon atom adjacent to the carbon attacked the hydroxyl group of side chain in 1. In the decomposition by electron impact of 1 and dimer of 1, the cleavage of the five-membered ring which corresponded to the molecular-ion peak for 2-imidazolidinone (m⁄z 86) was considered to take place after a successive cleavage of the side chain. On the basis of both kinetic studies and ESR or Mass spectral observations, the dimerization mechanism is fully discussed.