Ammonium carbonate is a salt with the chemical formula (NH₄)₂CO₃. Since it readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a

leavening agent In cooking, a leavening agent () or raising agent, also called a leaven () or leavener, is any one of a number of substances used in doughs and batters that cause a foaming action (gas bubbles) that lightens and softens the mixture. An altern ...

and also as

smelling salt Smelling salts, also known as ammonia inhalants, spirit of hartshorn or sal volatile, are chemical compounds used as stimulants to restore consciousness after fainting. Usage The usual active compound is ammonium carbonate—a colorless-to-w ...

. It is also known as baker's ammonia and is a predecessor to the more modern leavening agents

baking soda Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cation ( Na+) and a bicarbonate anion ( HCO3� ...

and

baking powder Baking powder is a dry chemical leavening agent, a mixture of a carbonate or bicarbonate and a weak acid. The base and acid are prevented from reacting prematurely by the inclusion of a buffer such as cornstarch. Baking powder is used to increas ...

. It is a component of what was formerly known as sal volatile and salt of hartshorn, and produces a pungent smell when baked.

Production

Ammonium carbonate is produced by combining carbon dioxide and aqueous ammonia. About 80,000 tons/year were produced as of 1997. An orthorhombic monohydrate is known. It crystallizes in an ammonia solution exposed in a carbon dioxide-rich atmosphere.

Decomposition

Ammonium carbonate slowly decomposes at

standard temperature and pressure Standard temperature and pressure (STP) are standard sets of conditions for experimental measurements to be established to allow comparisons to be made between different sets of data. The most used standards are those of the International Union ...

through two pathways. Thus any initially pure sample of ammonium carbonate will soon become a mixture including various byproducts. Ammonium carbonate can spontaneously

decompose Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ...

into

ammonium bicarbonate Ammonium bicarbonate is an inorganic compound with formula (NH4)HCO3. The compound has many names, reflecting its long history. Chemically speaking, it is the bicarbonate salt of the ammonium ion. It is a colourless solid that degrades readily to ...

and

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...

: : (NH₄)₂CO₃ → NH₄HCO₃ + NH₃ Which further decompose to

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

and another molecule of

: : NH₄HCO₃ → H₂O + CO₂ + NH₃

Uses

Leavening agent

Ammonium carbonate may be used as a

in traditional recipes, particularly those from northern Europe and Scandinavia (e.g. Amerikaner,

Speculoos Speculoos (sold as Biscoff in the United States and the United Kingdom) is a biscuit originally manufactured in Belgium. Although the name is similar to speculaas, speculoos is a different product. The biscuits are made without the mixture of spic ...

, Tunnbröd or

Lebkuchen (), or , are a honey-sweetened German cake molded cookie or bar cookie that has become part of Germany's Christmas traditions. It is similar to gingerbread. Etymology The etymology of ''Leb-'' in the term ''Lebkuchen'' is uncertain. Pro ...

). It was the precursor to today's more commonly used baking powder. Originally made from ground deer horn and called hartshorn, today it is called baker's ammonia. It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard, white or translucent mass. It acts as a heat activated leavening agent and breaks down into carbon dioxide (leavening), ammonia (which needs to dissipate) and water. It is sometimes combined with sodium bicarbonate to mimic as a double acting baking powder and to help mask any ammonia smell not baked out. It also serves as an

acidity regulator Acidity regulators, or pH control agents, are food additives used to change or maintain pH (acidity or basicity). They can be organic or mineral acids, bases, neutralizing agents, or buffering agents. Typical agents include the following acids ...

and has the

E number E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

E503. It can be replaced with baking powder, but this may affect both the taste and texture of the finished product. Baker's ammonia should be used to create thin dry baked goods like crackers and cookies. This allows the strong ammonia smell to bake out. It should not be used to make moist baked items like cake since ammonia is hydrophilic and will leave a strong bitter taste. Its use as a leavening agent, with associated controversy, goes back centuries:

Other uses

Ammonium carbonate is the main component of

smelling salts Smelling salts, also known as ammonia inhalants, spirit of hartshorn or sal volatile, are chemical compounds used as stimulants to restore consciousness after fainting. Usage The usual active compound is ammonium carbonate—a colorless-to-w ...

, although the commercial scale of their production is small. Buckley's cough syrup from Canada today uses ammonium carbonate as an active ingredient intended to help relieve symptoms of bronchitis. It is also used as an

emetic Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteritis ...

. It is also found in smokeless tobacco products, such as Skoal, and it is used in aqueous solution as a photographic lens cleaning agent, such as Eastman Kodak's "Kodak Lens Cleaner." It is also used for luring of apple maggots in

Washington State Washington (), officially the State of Washington, is a U.S. state, state in the Northwestern United States, Pacific Northwest region of the Western United States. Named for George Washington—the first President of the United States, U.S. p ...

, to monitor the spread of the infestation and adjust the borders of the Apple Maggot Quarantine Area. It is also used to reduce the amount of actual cocoa in a product, such as in Oreo cookies.“Mondelez develops enviro-friendly cocoa powder for Oreos” — Confectionery news.com
‘''Mondelez’s research subsidiary, Kraft Foods UK R&D, hinted in its patent application that the invention could allow Oreo cookies to use “significantly less cocoa powder”.''’

References