The difference between urea and uric acid

The difference between urea and uric acid

The difference between urea and uric acid

Although many get confused, urea and uric acid are two different compounds, which are different from each other. Urea is also excreted from the body through sweat. Uric acid is also excreted from the body, but it is the end product of urine metabolism. Therefore, it is always excreted in the urine.

Urea synthetic reactions

A urea plant using ammonium carbamate briquettes, Fixed Nitrogen Research Laboratory, was developed in 1922, also named after the discoverers of the Bosch-Meiser urea process. Different commercial urea processes are characterized by the conditions under which the urea is formed and how the unconverted reactants are further processed. This process involves two main equilibrium reactions, with incomplete conversion of the reactants.

  • The first carbamate formation is: rapid exothermic reaction of liquid ammonia with gaseous carbon dioxide (CO2) at high temperature and pressure to form ammonium carbamate. 

2 NH3+CO2 ⇌ H2N-COONH4

  • The second is urea conversion: the slower endothermic decomposition of ammonium carbamate into urea and water


The overall conversion of NH3 and CO2 to urea is exothermic, the heat of reaction resulting from the first reaction is the second factor. Like all chemical equilibria, these reactions also behave according to Lochatelier’s principle, and conditions that favor carbamate formation have an adverse effect on the urea conversion equilibrium. In direct urea plants, it is produced by reducing the pressure of the system to the atmosphere, so that the carbamate decomposes again into ammonia and carbon dioxide.

Urea in the body

Administering urea increases the osmolality of blood plasma and as a result increases the flow of water from tissues such as the brain, cerebrospinal fluid and eyes into interstitial fluids and plasma, as a result the pressure in these tissues decreases and urine flow increases. . Urea molecule is a polar molecule. Urea is a compound that contains nitrogen and is excreted through the kidneys. This substance is also the main component of urine. The body uses it in many processes, especially to eliminate nitrogen. The liver forms it by combining two molecules of ammonia (NH3) with one molecule of carbon dioxide (CO2) in the urea cycle.


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