Urea as an efficient reagent for the synthesis of 3-ethyl-3-(hydroxymethyl)oxetane: A novel component in cationic ring-opening polymerisation

Urea is a very attractive chemical raw material for large-scale production as it combines low cost with virtually unlimited supply and essentially no toxic effects. Here, we present a study on its use in the dehydration of tr imethylolpropane with formation of 3-ethyl-3-(hydroxymethyl)oxetane. The re action consists of carbonylation of trimethylolpropane and subsequent extru sion of carbon dioxide. The first step was run at a temperature of 120-160 degreesC at a pressure of approximately 300 mmHg for 1-5 h. Most likely, ca rbamates of TMP constitute the major product. In the latter step, the tempe rature was increased to 195-215 degreesC, the pressure was reduced to 10-50 mmHg, and the final product was isolated by distillation. A spiroorthocarb onate of TMP was formed as an unexpected byproduct. The process has been de monstrated on a multikilograin scale. Toxicological screening revealed 3-et hyl-3-(hydroxymethyl)oxetane to be irritating to eye but not to skin.