Remarkable Ammonia NH3 Properties, Synthesis, Reactions and Applications: Complete Guide

Ammonia is an inorganic substance with the formula NH3. The trigonal pyramidal structure of the ammonia molecule has a 106.7° bond angle. At room temperature and atmospheric pressure, it is an odorless gas with an unpleasant smell that is also very soluble in water. One of the most significant and popular industrial chemicals is ammonia. It is naturally present in the environment and has a wide range of uses in many different industries, including agriculture, refrigeration, chemical manufacturing, and cleaning.

It’s vital to remember that inhaling large volumes of poisonous ammonia gas can be bad for your health. Primarily, ammonia is utilized as a crucial ingredient in the manufacturing of fertilizers. It is a fantastic supplier of nitrogen, which is crucial for plant growth.

It is a chemical that is formed from nitrogenous plants and animal tissue and is present on Earth in minute amounts. Patagonia Guano has been found to contain ammonium bicarbonate crystals. Additionally, the planets Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto also contain ammonia.

Ammonia is a byproduct of the nitrogen metabolism in living things. Nitrogen-containing molecules are converted into ammonia by a variety of organisms, including bacteria, plants, and mammals, using processes like nitrogen fixation, nitrification, and ammonification.

Physical Properties:

  1. Molecular Weight: 17.03 g/mol-1.
  2. Density: Ammonia has a lower density than air, about 0.73 g/L-1.
  3. Freezing Point: Ammonia freezes into a white crystalline substance at -77.73°C (-107.91°F).
  4. Boiling Point: Ammonia boiling point is at -33.34°C.
  5. Solubility: It forms a strongly alkaline solution known as ammonium hydroxide when dissolved in water.

Chemical Properties:

  • Reactivity: It is a substance with a high level of reactivity. It performs the function of a base, rapidly taking up protons (H+) to create ammonium ions (NH4+). In some reactions, it can also take the role of a nucleophile.
  • Basicity: Ammonia act as a weak base. It can give up a single pair of electrons to join with an acid proton in a coordinating covalent connection.
  • Combustibility: It burns when oxygen is present. When burned in the air, it produces water vapour (H2O) and nitrogen gas (N2). Ammonia gas itself, however, is not flammable.
  • Reducing Agent: In some reactions, ammonia can function as a reducing agent, donating electrons to another material.

NH3 Synthesis/ production:

Haber process:

The most prevalent and economically feasible technique for synthesising ammonia is the highly energy-intensive Haber-Bosch process. Nitrogen gas (N2) from the air and hydrogen gas (H2) are combined during the process while being subjected to high pressure, high temperature conditions, and the presence of a catalyst.

1. Raw materials preparation:

Nitrogen gas is generated by passing air through an air separation device and then separating it. Nitrogen gas is separated from other components like oxygen after the air has been compressed and chilled to liquefy it. Steam reform is a common method for producing hydrogen gas from natural gas or other hydrocarbon sources. It involves the creation of hydrogen gas and carbon dioxide because of the interaction between steam (H2O) and natural gas (CH4) in the presence of a catalyst.

2. Gases Compression:

To raise the pressure, nitrogen and hydrogen gas are compressed after being extracted from their respective sources. To advance the reaction and produce larger ammonia yields, compression is required.

3. Mixing:

The correct stoichiometric ratio of compressed nitrogen gas and hydrogen gas is then combined. As the balanced equation to produce ammonia is, the optimal ratio is three molecules of hydrogen gas (H2) to one molecule of nitrogen gas (N2).

N2 + 3H2 → 2NH3.

4. Reaction Chamber:

The mixed gases are introduced into the reaction chamber, which is normally a sizable container made of steel or another suitable material that can handle high pressure and temperature. High pressure and a high temperature are among the ideal conditions the reaction chamber is made to offer for the synthesis of ammonia.

5. Reaction Prerequisites:

Between 100 and 250 atm of pressure is used to conduct the reaction. Normally, the temperature is between 350 and 550 oC. To speed up the reaction and increase process effectiveness, a catalyst is used. Iron or molybdenum are the most common catalysts used in the Haber process, and they are frequently coupled with modest amounts of promoters like aluminum oxide (Al2O3) or potassium oxide (K2O).

6. Reaction and Ammonia Formation:

In the presence of the catalyst, nitrogen gas and hydrogen gas undertake a chemical reaction to create ammonia gas at high pressures and temperatures. Exothermic means that while ammonia is generated, heat is released throughout the reaction.

7. Collection and Separation:

Following the reaction, the gas mixture that includes ammonia, unreacted nitrogen, unreacted hydrogen, and any byproducts is cooled to condense the ammonia gas. The condensed ammonia is gathered and put through additional purification steps, usually absorption or fractional distillation.

8. Purification and storage:

Any leftover impurities, such as residues of unreacted gases or other pollutants, are taken out of the collected ammonia during purification. Purified ammonia is subsequently transported or stored in the proper containers for industrial use in a variety of applications.

Ammonium salts electrolysis:

  • Using this technique, ammonia can be created by electrolyzing ammonium compounds such as ammonium sulphate (NH4)2SO4 or ammonium chloride NH4Cl. The ammonium salt solution is electrolyzed by running an electric current across it, which causes the salt to break down into byproducts like ammonia gas (NH3) and hydrogen gas (H2). It is possible to gather and further purify the ammonia gas for use.

Nitrogrn fixation:

  • Certain bacteria, referred to as nitrogen-fixing bacteria, can transform atmospheric nitrogen (N2) into ammonia through biological processes. These microorganisms coexist in soil independently or in symbiotic partnerships with specific plants, such as legumes. In a process known as nitrogen fixation, the bacteria use nitrogenase enzymes to turn nitrogen gas into ammonia. Nitrogen fixing bacteria can release ammonia into the soil, increasing the amount of nutrients there. However, it is currently not possible to harness this biological mechanism for the large-scale manufacture of ammonia.

Chemical reactions:

Ammonia is a flexible substance that can go through a variety of chemical processes because of the electronic lone pair present at the nitrogen atom. It is a key player in several industrial, inorganic, and organic chemical reactions because of its reactivity and capacity to function as a base and a nucleophile.

Acid-Base Reactions:

Ammonia functions as a base and easily forms ammonium salts when combined with acids. A single pair of electrons from the ammonia molecule are given to the acid’s proton as part of the reaction.

NH3 + HCl → NH4Cl (ammonium chloride)

NH3 + HNO3 → NH4NO3 (ammonium nitrate)

Redox Reactions:

Depending on the conditions of the reaction, ammonia can function as both an oxidizing and a reducing agent.

(a) Oxidizing reaction: 8NH3 + 3O2 → 6H2O + 4NO (nitric oxide)

(b) Reducing reaction: 2NH3 + 3CuO → 3H2O + N2 + 3Cu (reduction of copper oxide)

Combustion:

Ammonia can ignite in a combustion reaction with enough oxygen present to produce water and nitrogen gas. The reaction produces a lot of heat.

4NH3 + 3O2 → 6H2O + 2N2

Reaction with Halogens:

Halide salts can be created when ammonia reacts with halogens like chlorine (Cl2) and bromine (Br2).

NH3 + Cl2 → NH2Cl (chloramine)

NH3 + Br2 → NH2Br + HBr (formation of bromamine)

Reaction with Metals:

Ammonia and some metals can combine to generate metal amides or imides. In these processes, the hydrogen atom in ammonia is frequently exchanged out for a metal atom. 

2NH3 + 2Na → 2NaNH2 + H2 (sodium amide)

Reaction with Aldehydes and Ketones:

Ammonia can generate imines or iminium salts when it interacts with aldehydes and ketones. The Amine Formation Reaction is the name given to this process.

CH3CHO + NH3 → CH3CH=NH + H2O (methylamine)

Dehydration:

Ammonia can dehydrate at high temperatures, releasing nitrogen and hydrogen gases. The progression of this reversible process demands high temperatures.

2NH3 ⇌ N2 + 3H2

Versatile applications:

Ammonia (NH3) has a wide range of applications across various industries. Its unique chemical properties make it useful in several processes.

  • Food and Beverage business: Ammonia is utilized as a pH regulator and antibacterial agent in the food and beverage business. It can function as a leavening agent in baking and aids in maintaining the pH balance in food products.
  • Textile Industry: Ammonia is used in the dyeing, printing, and finishing stages of several textile processes. It contributes to the fixing of dyes and helps make textile materials more colorfast.
  • Nitrogen Cycling: The nitrogen cycle is the method through which nitrogen is changed and recycled in ecosystems. Ammonia is a crucial part of this process. It is possible for plants to use nitrites and nitrates as nutrients by converting ammonia, which is produced by decomposers and other organisms.
  • Cleaning and Disinfection: Cleaning solutions with an ammonia basis are frequently used in households, especially on surfaces made of glass, stainless steel, and ceramic. 5–10% by weight ammonia solutions are used as cleaning agents around the house, especially for glass. The mucous membranes of the respiratory and digestive systems, as well as the eyes, are irritated by these solutions, but the skin is only slightly affected. Ammonia is a powerful cleaning agent because of its alkaline nature, which makes it useful for eliminating stains, grease, and dirt.
  • Wastewater Treatment: Ammonia is used to eliminate pollutants, notably nitrogen compounds, from wastewater. This is a critical step in the process. It facilitates the transformation of poisonous nitrogenous molecules into less dangerous forms like nitrate or nitrogen gas.
  • Fertilizer production: Ammonia is a crucial ingredient in the manufacture of nitrogen-based fertilizers like urea and ammonium nitrate. It gives plants an easy way to get the nitrogen they need for optimum growth and development. It contributes to higher crop yields for crops like wheat and maize when applied to the soil.
  • Industrial compounds: Nitric acid, sulfuric acid, and hydrogen cyanide are just a few of the compounds that ammonia is used to make. Explosives, dyes, polymers, pharmaceuticals, and other significant goods are produced using these compounds.
  • Air conditioning and refrigeration: Ammonia is frequently utilized as a refrigerant in substantial air conditioning and refrigeration systems. In comparison to some synthetic refrigerants, it is regarded as having great thermodynamic qualities and being more environmentally benign.
  • Protein production: Ammonia is a necessary ingredient to produce proteins in living things.  Through a process known as transamination, ammonia is converted into amino acids, which serve as the building blocks of proteins, in cells. Cells employ these amino acids to create the proteins required for numerous biological processes.

Safety considerations:

  • Ammonia can burn severely and irritate the skin and eyes when it comes in touch with them. When handling ammonia, personal protective equipment such gloves, goggles, and protective clothes should be worn to avoid getting it in your eyes or on your skin.
  • Ammonia is not flammable by itself, but when other compounds, such as oxidizers, are present, it can act as a fuel and facilitate combustion. Ammonia should be stored in proper ammonia storage containers such as pressure tanks or cylinders.
  •  Avoid storing or utilizing ammonia close to open flames, sparks, or other ignition sources. Storage spaces should be secure, well-ventilated, and far from compounds that are incompatible. To avoid unintentional exposure or misuse, storage spaces and container labels must be properly applied.
  • Ammonia gas causes severe respiratory system irritation. High amounts can be inhaled and cause severe discomfort, coughing, and breathing problems.
  • When handling or utilizing ammonia, it’s crucial to work in well-ventilated spaces. Make sure the right ventilation systems are in place if you’re working inside.

Conclusion:

In conclusion, ammonia is a versatile substance with a variety of uses in cleaning, agriculture, refrigeration, and chemical production. Due to its significance in these industries, it is an essential component for many different economic sectors.

Is ammonia poisonous to living things?

Ammonia is a naturally occurring byproduct of biological processes, but at large concentrations, it can be hazardous to living things. Ammonia detoxification and conversion into less harmful molecules are processes that organisms have developed. Ammonia is predominantly converted to urea in animals, including humans, in the liver through a process known as the urea cycle, which is ultimately eliminated from the body through urine.

What are the natural origins of ammonia?

It can be obtained from the waste products by fish and other aquatic species, and at high concentrations, it can be hazardous to them. Ammonia is transformed by some aquatic microorganisms, such as nitrifying bacteria, into less poisonous nitrites and nitrates, which are then used as nutrients by plants and algae. Several aquatic invertebrates and even amphibians directly emit ammonia as their main nitrogenous waste product. They can conserve water owing to this adaptation, but they need to reside in areas with plenty of water to eliminate and dilute the harmful ammonia.