Chemical reaction involving repeated halogenation of an acetyl group (–COCH3)
Haloform reaction
Named after
Adolf Lieben
Reaction type
Substitution reaction
Identifiers
Organic Chemistry Portal
haloform-reaction
RSC ontology ID
RXNO:0000689
In chemistry, the haloform reaction is a chemical reaction in which a haloform (CHX3, where X is a halogen) is produced by the exhaustive halogenation of an acetyl group (R−C(=O)CH3, where R can be either a hydrogen atom, an alkyl or an aryl group), in the presence of a base.[1][2][3] The reaction can be used to transform acetyl groups into carboxyl groups (R−C(=O)OH) or to produce chloroform (CHCl3), bromoform (CHBr3), or iodoform (CHI3). Note that fluoroform (CHF3) can't be prepared in this way.
Haloform reaction scheme
^March, Jerry; Smith, Michael B. (2007). Knipe, A.C. (ed.). March's Advanced Organic Chemistry Reactions, Mechanisms, and Structure (6th ed.). Hoboken: John Wiley & Sons. p. 484. ISBN 9780470084946.
^Reynold C. Fuson and Benton A. Bull (1934). "The Haloform Reaction". Chemical Reviews. 15 (3): 275–309. doi:10.1021/cr60052a001.
^Chakrabartty, in Trahanovsky, Oxidation in Organic Chemistry, pp. 343–370, Academic Press, New York, 1978
In chemistry, the haloformreaction is a chemical reaction in which a haloform (CHX3, where X is a halogen) is produced by the exhaustive halogenation...
of the haloforms — specifically, chloroform (CHCl3), bromoform (CHBr3), and iodoform (CHI3) — are easy to prepare through the haloformreaction, although...
reduction With halogens to form an α-haloketone, a reaction that proceeds via an enol (see Haloformreaction) With heavy water to give an α-deuterated ketone...
independently by John Thomas Cooper. It is synthesized in the haloformreaction by the reaction of iodine and sodium hydroxide with any one of these four...
Friedel-Crafts halogenation, using chlorine and a Lewis acid catalyst. The haloformreaction, using chlorine and sodium hydroxide, is also able to generate alkyl...
The haloformreaction can also occur inadvertently in domestic settings. Bleaching with hypochlorite generates halogenated compounds in side reactions; chloroform...
the haloformreaction Base-catalyzed cleavage of non-enolizable ketones, especially aryl ketones: R−C(=O)−Ar + H2O → R−CO2H + ArH Many reactions produce...
or carboxylic acids. Calcium hypochlorite can also be used in the haloformreaction to manufacture chloroform. Calcium hypochlorite can be used to oxidize...
with water to form a carboxylate (−C(=O)O−) in what is known as the haloformreaction. The regioselectivity also differs: The halogenation of an unsymmetrical...
product can undergo a subsequent retro-aldol reaction, giving an overall process similar to the haloformreaction. For example, nitric oxide reacts with acetone...
often as acyl hypohalites (see the Hunsdiecker reaction). Sodium hypohalite is used in the haloformreaction as a test for methyl ketones. The Cl-O bond...
Cl2 + CH3CH2OH + H2O → Cl3C−CH(OH)2 + 5 HCl In basic conditions the haloformreaction takes place and chloral hydrate is decomposed by hydrolysis to form...
Friedel-Crafts halogenation, using chlorine and a Lewis acid catalyst. The haloformreaction, using chlorine and sodium hydroxide, is also able to generate alkyl...
preparation of chloroform from chloral. Bromoform can be prepared by the haloformreaction using acetone and sodium hypobromite, by the electrolysis of potassium...
the corresponding haloform (CHX3, where X = Cl, Br, I). This conversion is called the haloformreaction. An intermediate in the reaction with chlorine is...
Justus von Liebig (Germany), all of them using variations of the haloformreaction. Dandelin–Gräffe method, aka Lobachevsky method – an algorithm for...
products. If a base is present, bromoform is obtained instead, by the haloformreaction. It was used in World War I as a chemical weapon, called BA by British...
Berlin," "Gazzetta Chimica Italiana, Palermo," etc. Lieben haloformreaction Hunsdiecker reaction This article incorporates text from a publication now in...
strong base; for example, phenyllithium will abstract HX from a haloform (CHX3). Such reactions typically require phase-transfer conditions.[citation needed]...
and triphenylphosphine; the co-products are haloform and triphenylphosphine oxide. In the Mitsunobu reaction, the reagents are any nucleophile, triphenylphosphine...
formula CHF3. It is a hydrofluorocarbon as well as being a part of the haloforms, a class of compounds with the formula CHX3 (X = halogen) with C3v symmetry...
aldehydes (RCHO) -> (E)-haloalkenes (RCH:CHX) conversion by means of a haloform-chromous chloride system". Journal of the American Chemical Society. 108...
trifluoromethyl free radical. Reagents such as bromotrifluoromethane and haloform have been used for this purpose but in response to the Montreal Protocol...
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