Urea Preparation by Oxidative Carbonylation of Ammonia

Effective one-stage method of urea preparation by catalytic oxidative carbonylation of ammonia in liquid phase is developed. The method allows to prepare urea with productivity of ~530 g/(L·h) in sufficiently mild conditions (total pressure ~30 bar, 45 °C). The process is characterized by high selectivity (near 100%) i.e. byproducts separation is not needed. Almost all CO is consumed during the process, this substantially diminishes the waste-gas purification costs and raises the process environmental characteristics; the only byproduct is water.