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

Abstract

A series of zinc-iron double oxide catalysts has been prepared. The suitable preparation condition 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, CO2-TPD and XPS techniques have been employed for catalyst characterization. Two kinds of crystal phase, ZnO and ZnFe2O4, have been detected and their synergistic effect promotes the catalytic activity of the oxide catalysts. © 2006 Society of Chemical Industry.