Clean synthesis of propylene carbonate from urea and 1,2‐propylene glycol over zinc–iron double oxide catalyst

A series of zinc–iron double oxide catalysts has been prepared. The suitable preparation conditions are as follows: zinc nitrate and iron nitrate as precursors, molar ratio of Zn/Fe 2:1, ammonia as the precipitant, precipitation end‐point pH 8.04, and calcination temperature 450 °C. The clean synthesis of propylene carbonate (PC) via urea and 1,2‐propylene glycol (PG) over the zinc–iron double oxide catalyst has been studied. The optimal reaction conditions are as follows: reaction temperature 170 °C, reaction time 2 h, catalyst concentration 1.4% (wt), and molar ratio of urea to PG 1:4. The highest yield of PC was 78.6%. XRD, CO 2 ‐TPD and XPS techniques have been employed for catalyst characterization. Two kinds of crystal phase, ZnO and ZnFe 2 O 4 , have been detected and their synergistic effect promotes the catalytic activity of the oxide catalysts. Copyright © 2006 Society of Chemical Industry