Bromoacetone is a chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 ₃CCH₂. This colorless liquid is a lachrymatory agent

Lachrymatory agent

Tear gas, formally known as a lachrymatory agent or lachrymator , is a non-lethal chemical weapon that stimulates the corneal nerves in the eyes to cause tears, pain, and even blindness...

. It is a precursor to other organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s.

Bromoacetone was first prepared in the 19th century. It was used in World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 as a chemical weapon, called BA by British and B-Stoff (white cross) by Germans. Due to its toxicity, it is obsolete as a riot control agent and is not used anymore.

Occurrence

Bromoacetone is naturally present (less than 1%) in the essential oil

Essential oil

An essential oil is a concentrated hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile oils, ethereal oils or aetherolea, or simply as the "oil of" the plant from which they were extracted, such as oil of clove...

 of a seaweed

Seaweed

Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...

 from the vicinity of the Hawaiian Islands

Hawaiian Islands

The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...

. In atmosphere it is degraded by the photochemically produced hydroxyl

Hydroxyl

A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

 radicals

Radical (chemistry)

Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...

.

Synthesis

Bromoacetone is available commercially, sometimes stabilized with magnesium oxide

Magnesium oxide

Magnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...

.

Bromoacetone is prepared by reacting bromine

Bromine

Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...

 and acetone

Acetone

Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...

, with catalytic acid. If you use a base you will obtain bromoform instead.
CH₃C(O)CH₃ + Br₂ → CH₃C(O)CH₂Br + HBr

As with all ketones, acetone enol

Enol

Enols are alkenes with a hydroxyl group affixed to one of the carbon atoms composing the double bond. Alkenes with a hydroxyl group on both sides of the double bond are called enediols. Deprotonated anions of enols are called enolates...

izes in the presence of acids or bases. The alpha carbon then undergoes electrophilic substitution

Electrophilic substitution

Electrophilic substitution reactions are chemical reactions in which an electrophile displaces a group in a compound, typically but not always hydrogen. Electrophilic aromatic substitution is characteristic of aromatic compounds and is an important way of introducing functional groups onto benzene...

 with bromine. The main difficulty with this method is over-bromination, resulting in di- and tribrominated products.

Applications

Bromoacetone is a versatile reagent

Reagent

A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...

 in organic synthesis

Organic synthesis

Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...

. It is, for example, the precursor to hydroxyacetone (b.p. 35–47°/12 mm, CAS #116-09-6).