Polyureas, which contain the –NHCONH– unit in their backbone, have a wide variety of uses, such as in foams, fibres and biomedical applications. Traditionally, they are made via a process that uses toxic carbonylating agents such as phosgene or isocyanate, and the by-products of the reaction are also hard to recycle. Needless to say, it would be desirable to produce polyureas by a more environmentally friendly method.
In this paper, the authors report one such technique. They have synthesised a polyurea, -oligourea, with a microwave assisted method that uses a green carbonylating agent and an organocatalyst. After optimising the experimental conditions, they found that with 10W of fixed-mode microwave energy applied to the reactants, they were able to achieve almost 100% yield. The by-products of the reaction are also more easily recycled than from traditional methods.
This synthetic method opens the way to producing polyureas in a eco-friendly, efficient way.
Read their paper to find out more:
Highly efficient isocyanate-free microwave-assisted synthesis of -oligourea
Abdussalam K. Qaroush, Asmaa S. Al-Hamayda, Yasmeen K. Khashman, Sergei I. Vagin, Carsten Troll and Bernhard Rieger
Catal. Sci. Technol., 2013, Advance Article
DOI: 10.1039/C3CY00117B, Paper