Well-Defined CeO₂ as Efficient Catalysts for the Green Synthesis of Pentamethylene Dicarbamate via Carbonylation of 1,5-Pentanediamine with Methyl Carbamate

Bio-based pentamethylene dicarbamate (PDC) belongs to N-substituted carbamates, which are important fine chemicals and organic intermediates. In this work, well-defined CeO2 rods, cubes, and octahedrons were successfully prepared to catalyze the synthesis of PDC by carbonylation of 1,5-pentanediamine (PDA) with methyl carbamate (MC). Among them, CeO2 rods with higher amounts of acid–base sites and abundant oxygen vacancies showed superior intrinsic activity in the PDA carbonylation reaction. In situ FTIR results showed that intermediate polyureas were readily formed in the reaction, and then, CeO2 rods promoted the alcoholysis of polyureas to PDC. In situ DRIFTS results indicated that the surface of CeO2 rods is more favorable for the adsorption and activation of the reactants. CeO2 rods can also be used for the efficient synthesis of a series of N-substituted carbamates. We believe that this work will contribute to the efficient, green, and sustainable production of N-substituted carbamates.