What are the uses for ammonia

Hazard classes + category

Flammable gases 2
Gases under pressure, compressed. gas
Acute toxicity inhalation 3
Skin corrosion / irritation 1B
Acute aquatic hazard 1
HP rates (See note)

H 221, 280, 314, 331, 400, EUH071
P 210, 260, 273, 280.1-3 + 7, 303 + 361 + 353, 304 + 340,
305+351+338, 315, 377, 381, 403, 405

disposal special instructions
GHS 04
GHS 05
GHS 06
GHS 09
Special notes for the school
Do not keep gas bottles with ammonia in schools! To demonstrate the properties, the gas can be expelled from concentrated ammonia solution by heating. You have to work in the fume cupboard. Safety glasses and protective gloves must be worn. The fountain experiment itself is possible in the technical room as a demo experiment with good ventilation, since a closed apparatus is used. As a brief vacuum occurs, the spectators must also wear protective goggles or a protective screen is used.

Risk assessment Germany (also EU)
GBU Working with ammonia: experiment with a fountain

Security assessment of Switzerland

SB Working with ammonia: fountain experiment
Effect on the human body

The information in the literature on the odor threshold up to the lethal dose varies greatly. This is probably also due to the fact that the effects of ammonia vary from person to person. Based on the available literature and our own experiments, the odor threshold should be between 0.1 ppm and 3 ppm. From around 100 ppm to 200 ppm, irritation of the mucous membranes and eyes can occur. In the beginning, the entire amount of ammonia absorbed is absorbed by the fluid in the nasal and oral mucosa. The nose feels dry, the mucous membranes and eyes become irritated. Even higher concentrations attack the upper respiratory tract and cause coughing, breathing difficulties or nausea. In allergy sufferers and asthmatics, this effect occurs even at lower concentrations. Above 1700 ppm there is danger to life [Lit. Gestis, 2013], a lethal effect occurs at 2000 ppm [lit. Daunderer 1987] up to 5000 ppm [LCLo value, Lit. ChemIdPlus, 2013]. Brief exposure to high concentrations can lead to inflammation in the airways or pulmonary edema. Then there is an acute danger to life. The absorption of ammonia solution into the stomach causes gastric bleeding and circulatory collapse.

Reaction of ammonia with hydrogen chloride.

Fountain experiment with ammonia.

Chemical-physical properties

Ammonia is a colorless, pungent smelling gas. It is extremely soluble in water; 520 liters of gas dissolve in one liter of water at 20 ° C. The solution of the gas in water is called ammonia solution or ammonia. Ammonia combines with acids to form ammonium salts; when it comes into contact with hydrogen chloride, a white ammonium chloride smoke is formed in a neutralization process.

NH3 + HCl NH4Cl

The gas is relatively stable at room temperature. At higher temperatures under the influence of catalysts or when exposed to UV light or an electrical spark discharge, ammonia breaks down into nitrogen and hydrogen:

2 NH3  N2 + 3 H.2   ΔHR. = +92 kJ / mol

Ammonia-air mixtures are explosive within the explosion limits. At higher temperatures, ammonia can be burned:

4 NH3 + 3 O2  2 N2 + 6 H.2O ΔHR. = −1532 kJ / mol

With nitric acid, ammonium nitrate is formed:

ENT3 + NH3  NH4NO3 
Even the ancient Egyptians produced salmiac through the putrefaction of nitrogen-containing organic waste such as urine or animal manure. In 1727 Stephen Hales (1677–1771) obtained gaseous ammonia by heating a mixture of lime and ammonia. Carl Wilhelm Scheele (1742–1786) and Humphry Davy (1778–1829) were involved in determining the chemical composition. In the second half of the 19th century, ammonia was produced in industry as a by-product in the washing water of coal gasification. In 1898 F. Rothe discovered the manufacturing process using the calcium cyanamide process. Calcium carbide and nitrogen initially formed calcium cyanamide (calcium cyanamide, CaCN2) which, when heated with steam, decomposed into calcium carbonate and ammonia. The so-called Rothe-Frank-Caro process enabled the industrial production of ammonia for the first time:

CaC2 + N2  CaCN2 + C
CaCN2 + 3 H.2O CaCO3 + 2 NH3   

In 1900 Wilhelm Ostwald (1853–1932) registered a patent "Production of ammonia and ammonia compounds from free nitrogen and hydrogen" at. He succeeded on a laboratory scale "Suitable contact substances or catalysts even with low heating to 250 to 300 ° C" To produce ammonia. In the same patent he recommended performing under high pressure, "Because the relative amount of ammonia in the gas mixture increases with increasing pressure". Ostwald sold the patent to BASF. From his idea, Fritz Haber (1868–1934) and Carl Bosch (1874–1940) were able to develop an industrial process for the production of ammonia on an industrial scale. The Haber-Bosch process is the most important today.

In the laboratory, ammonia can be produced by heating ammonia solution saturated with calcium chloride or by heating a mixture of calcium hydroxide and ammonium chloride:

2 NH4Cl + Ca (OH)2  CaCl2 + 2 NH3 + 2H2O