Synthesis of Ureas from CO2

Abstract

Ureas are an important class of bioactive organic compounds in organic chemistry and exist widely in natural products, agricultural pesticides, uron herbicides, pharmaceuticals. Even though urea itself has been synthesized from CO and ammonia for a long time, the selective and efficient synthesis of substituted ureas is still challenging due to the difficulty of dehydration processes. Efficient and economic fixation of CO is of great importance in solving the problems of resource shortages, environmental issues, global warming, etc. During recent decades, chemists have developed different catalytic systems to synthesize ureas from CO and amines. Herein, we focus on catalytic synthesis of ureas using CO and amines.

Recent Advances in the Chemical Fixation of Carbon Dioxide: A Green Route to Carbonylated Heterocycle Synthesis

“…The synthesis of urea itself was the founder of modern organic chemistry. However, the selective and efficient synthesis of substituted ureas and in particular of cyclic ureas from CO 2 and amines is still challenging [188,189].…”

“…The direct carboxylation of diamines with carbon dioxide is another attractive manufacture of cyclic ureas. In the past years some catalysts have been introduced for this reaction and have been discussed in the reviews cited at the top of this section [188,189]. However, in the time range covered by us other interesting papers appeared in the literature.…”

Thermal and Thermoelectric Properties of Molecular Junctions

“…where G 0 is the quantum of electrical conductance and has a value of 2 77.48 S 2 e h ≈ µ and E F is the Fermi energy (chemical The above expressions (Equations (1) and (2)) assume that an electron remains phase coherent as it passes from one electrode to the another and does not undergo inelastic scattering. [19b] However, as the length of a molecule increases, the probability of inelastic scattering (e.g., from phonons or other electrons) becomes non-negligible and the above expressions may require further correction or modification.…”

A Thermomorphic Polyethylene‐Supported Imidazolium Salt for the Fixation of CO2 into Cyclic Carbonates

“…For instance, CO 2 is mainly used for the direct carboxylation of organic substrates, for incorporation into heterocycles and for methylation reactions . Additionally, carbon dioxide is already used to produce urea on an industrial scale (120 Mt/year) . Another industrial application is the synthesis of propylene carbonate from propylene oxide and CO 2 with 100% atom economy.…”