Diketene
Encyclopedia
Diketene is an organic compound
formed by dimerization of ketene
. Diketene is a member of the oxetane
family. It is used as a chemical reagent in organic chemistry
. It is a colorless liquid and heating regenerates the ketene monomer. Alkylated ketenes also dimerize with ease and form substituted diketenes.
Diketene readily hydrolyses in water forming acetoacetic acid
, its half-life
in pure water is approximately 45 minutes a 25°C at 2<pH
<7. Diketene also reacts with alcohol
s and amine
s to the corresponding acetoacetic acid derivatives. An example is the reaction with 2-aminoindane
:
Despite its high reactivity as an alkylating agent, and unlike analogue β-lactones propiolactone
and β-butyrolactone, diketene is inactive as a carcinogen, possibly due to the instability of its DNA adduct
s.
Diketene is an important industrial intermediate used for the production of acetoacetate esters and amides as well as substituted 1-phenyl-3-methylpyrazolones. The latter are used in the manufacture of dyestuffs and pigments.
Certain diketenes with two aliphatic chain
s, such as alkyl ketene dimer (AKD), are used industrially to improve hydrophobicity
in paper
.
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...
formed by dimerization of ketene
Ketene
A ketene is an organic compound of the form R'RC=C=O. The term is also used specifically to mean ethenone, the simplest ketene, where R' and R are hydrogen atoms.Ketenes were first studied as a class by Hermann Staudinger.-Formation:...
. Diketene is a member of the oxetane
Oxetane
Oxetane, or 1,3-propylene oxide, is an heterocyclic organic compound with the molecular formula C3H6O, having a four-membered ring with three carbon atoms and one oxygen atom....
family. It is used as a chemical reagent in organic chemistry
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
. It is a colorless liquid and heating regenerates the ketene monomer. Alkylated ketenes also dimerize with ease and form substituted diketenes.
Diketene readily hydrolyses in water forming acetoacetic acid
Acetoacetic acid
Acetoacetic acid is the organic compound with the formula CH3CCH2CO2H. It is the simplest beta-keto acid group and like other members of this class is unstable.- Synthesis and properties :...
, its half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
in pure water is approximately 45 minutes a 25°C at 2<pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
<7. Diketene also reacts with alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
s and amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
s to the corresponding acetoacetic acid derivatives. An example is the reaction with 2-aminoindane
Indane
Indane or indan is a hydrocarbon petrochemical compound.-Derivatives:Derivatives include compounds such as 1-methyl-indane and 2-methyl-indane , 4-methyl-indane and 5-methyl-indane , various dimethyl-indanes, and various pharmaceutical derivatives...
:
Despite its high reactivity as an alkylating agent, and unlike analogue β-lactones propiolactone
Propiolactone
β-Propiolactone is an organic compound of the lactone family, with a four-membered ring. It is a clear, colorless liquid with a slightly sweet odor, highly soluble in water and miscible with ethanol, acetone, diethyl ether and chloroform...
and β-butyrolactone, diketene is inactive as a carcinogen, possibly due to the instability of its DNA adduct
DNA adduct
In molecular genetics, a DNA adduct is a piece of DNA covalently bonded to a chemical. This process could be the start of a cancerous cell, or carcinogenesis. DNA adducts in scientific experiments are used as biomarkers of exposure and as such are themselves measured to reflect quantitatively,...
s.
Diketene is an important industrial intermediate used for the production of acetoacetate esters and amides as well as substituted 1-phenyl-3-methylpyrazolones. The latter are used in the manufacture of dyestuffs and pigments.
Certain diketenes with two aliphatic chain
Aliphatic compound
In organic chemistry, aliphatic compounds are acyclic or cyclic, non-aromatic carbon compounds.Thus, aliphatic compounds are opposite to aromatic compounds.- Structure :...
s, such as alkyl ketene dimer (AKD), are used industrially to improve hydrophobicity
Hydrophobe
In chemistry, hydrophobicity is the physical property of a molecule that is repelled from a mass of water....
in paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
.