Infra-red Study of the Reactions between Ethyl Isocyanate and the Surface of Magnesium Oxide

Abstract

Ethyl isocyanate reacts at 306 K with isolated hydroxyl groups on the surface of magnesium oxide to form a urethane. The adsorption reaction is reversed by evacuation at high temperatures. Adjacent interacting hydroxyl groups and molecular water on magnesium oxide react with ethyl isocyanate to give 1,3-diethylurea which is adsorbed on the oxide as a perturbed “carboxylate-type complex” and carbon dioxide which with water gives a surface bicarbonate species. The 1,3-diethylurea complex decomposes to surface ethyl magnesium carbonate on evacuation at elevated temperatures. The latter species is also formed when ethyl isocyanate reacts with the surface of magnesium oxide at 673 K. Other products of the high temperature reaction include cyanide and isocyanate groups as ligands of surface magnesium ions, adsorbed carbonate ions, and products of the polymerization reactions of ethyl isocyanate, isocyanic acid, and hydrogen cyanide.