It is an amide derivative of carbamic acid (NH2.COOH). Hence it is also called Carbamide. Its IUPAC name is Amino Methanamide. It is an important compound. Urea is formed due to the decomposition of proteins in the body.
About 30 grams of urea is excreted through urine daily in a healthy human body. It is the first organic compound made in the laboratory. Roulle first obtained it from Urine in 1773. Hence it is named simple urea.
After evaporating the urine, the concentrated nitric acid is added to it, causing the nitrate to separate into crystals. On filtering it, urine is produced by reaction with barium carbonate. It is separated by crystallization.
In the laboratory urea is produced by the action of ammonia on carbonyl chloride or ethyl carbonate.
Urea is the first organic compound made in the laboratory. It was first created in the laboratory by Friedrich Wöhler in 1828 by heating a mixture of Potassium cyanate and ammonium sulfate. Ammonium cyanate is formed due to the ionic reaction of potassium cyanate and ammonium sulfate. In which urea is formed by reorganization of atoms.
Ammonium carbamate is formed by heating a mixture of liquid ammonia and liquid carbon dioxide in autoclave at high temperature. Which is obtained by heating to 150°C at 50 atmospheric pressure.
2NH3 + CO2 → NH2COONH4
NH2COONH4 → NH2CONH2 + H2O
In this method, firstly, the mixture of calcium carbide and nitrogen to calcium cyanamide and carbon is obtained according to the following reaction. This mixture is called nitrolimeand is used as fertilizer.
CaC2 + N2 → CaCN2 + C
This mixture is reacted with dilute sulfuric acid. Dilute sulfuric acid converts calcium cyanamide into cyanamide. This is followed by urea from partial water decomposition of Cyanamide.
CaCN2 + H2SO4 → H2N-C≡N + CaSO4
H2N-C≡N + H2O → H2N-CO-NH2
Urea is a white crystal substance. Its melting point is 132°C. It is more fusion between alcohol and water but is insoluble in ether.
Water Decomposition: Water decomposition of urea occurs when heated with water at high pressure or boiled with alkali or acid. Which gives carbon dioxide and ammonia gas.
Water decomposition of urea occurs quickly when urea is heated with an aqueous solution of NaOH or KOH. Ammonia gas is obtained in this reaction. This reaction can be used to test urea.
NH2CONH2 + 2NaOH → Na2CO3 + 2NH3
Reaction with Acids: Aqueous solution of urea is a weak alkali-like behavior.
Example: It reacts with concentrated nitric acid and concentrated oxalic acid to make urea nitrate and urea oxylate respectively.