Urea as an Efficient Reagent for the Synthesis of 3-Ethyl-3-(hydroxymethyl)oxetane:  A Novel Component in Cationic Ring-Opening Polymerisation

• Published in: Organic process research & development 2001-11, Vol.5 (6), p.568-571
• Main Authors: Annby, Ulf, Rehnberg, Nicola, Samuelsson, Jesper, Teichert, Oliver
• Format: Article
• Language: English
• ISSN: 1083-6160; 1520-586X
• DOI: 10.1021/op010037j

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 trimethylolpropane with formation of 3-ethyl-3-(hydroxymethyl)oxetane. The reaction consists of carbonylation of trimethylolpropane and subsequent extrusion of carbon dioxide. The first step was run at a temperature of 120−160 °C at a pressure of approximately 300 mmHg for 1−5 h. Most likely, carbamates of TMP constitute the major product. In the latter step, the temperature was increased to 195−215 °C, the pressure was reduced to 10−50 mmHg, and the final product was isolated by distillation. A spiroorthocarbonate of TMP was formed as an unexpected by-product. The process has been demonstrated on a multikilogram scale. Toxicological screening revealed 3-ethyl-3-(hydroxy-methyl)oxetane to be irritating to eye but not to skin.