Synthesis of diethylcarbonate by ethanolysis of urea: A study on the recoverability and recyclability of new Zn-based heterogeneous catalysts

• New Zn-based heterogeneous catalysts for the ethanolysis of urea are described.
• The role of different frameworks on the stabilization of Zn centres has been determined.
• The Zn-leaching in the reaction medium is strongly reduced with respect to pure ZnO.
• The new catalysts have a higher specific activity (per Zn-centre) with respect to ZnO.
• The heterogeneous catalysts are easily recovered and recycled.

New Zn-based catalysts are described that act as heterogenized or heterogeneous catalysts, with easy recovery and re-utilization with a limited or even zero Zn-leaching. For stabilizing in the heterogeneous form the catalytically active Zn centre, mixed oxides, ZIF-8 and Zn-tethered systems have been synthesized and found to sensibly reduce the leaching of Zn in solution with respect to ZnO, making possible their recovery and reuse. ZIF-8 can be used for long time of reaction, reaching high DEC yields (comparable or higher than those obtained with ZnO) without any significant loss of zinc.

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