Diketene

Last updated
Diketene
Diketene-2D-skeletal.png
Diketene-from-xtal-3D-balls.png
Names
Preferred IUPAC name
4-Methylideneoxetan-2-one
Other names
γ-Methylenepropiolactone
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.010.562 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 211-617-1
PubChem CID
RTECS number
  • RQ8225000
UNII
UN number 2521
  • InChI=1S/C4H4O2/c1-3-2-4(5)6-3/h1-2H2 Yes check.svgY
    Key: WASQWSOJHCZDFK-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C4H4O2/c1-3-2-4(5)6-3/h1-2H2
    Key: WASQWSOJHCZDFK-UHFFFAOYAM
  • O=C1OC(=C)C1
Properties
C4H4O2
Molar mass 84.074 g·mol−1
Density 1.09 g cm−3
Melting point −7 °C (19 °F; 266 K)
Boiling point 127 °C (261 °F; 400 K)
Viscosity 0.88 mPa.s
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-acid.svg GHS-pictogram-skull.svg GHS-pictogram-exclam.svg
Danger
H226, H301, H302, H315, H318, H330, H331, H332, H335
P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P280, P284, P301+P310, P301+P312, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P311, P312, P320, P321, P330, P332+P313, P362, P370+P378, P403+P233, P403+P235, P405, P501
Flash point 33 °C (91 °F; 306 K)
275
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Diketene is an organic compound with the molecular formula C4H4O2, and which is sometimes written as (CH2CO)2. It is formed by dimerization of ketene, H2C=C=O. Diketene is a member of the oxetane family. It is used as a reagent in organic chemistry. [1] It is a colorless liquid.

Contents

Production

Diketene is produced on commercial scale by dimerization of ketene. [2]

Reactions

Heating or irradiation with UV light [3] regenerates the ketene monomer:

Alkylated ketenes also dimerize with ease and form substituted diketenes.

Diketene readily hydrolyzes in water forming acetoacetic acid. Its half-life in water is approximately 45 min. a 25 °C at 2 < pH < 7. [4]

Certain diketenes with two aliphatic chains, such as alkyl ketene dimers (AKDs), are used industrially to improve hydrophobicity in paper.

At one time acetic anhydride was prepared by the reaction of ketene with acetic acid: [5]

Acetoacetylation

Diketene also reacts with alcohols and amines to the corresponding acetoacetic acid derivatives. The process is sometimes called acetoacetylation. An example is the reaction with 2-aminoindane: [6]

DiketeneReaction.svg

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. [7] A typical reaction is:

These acetoacetamides are precursors to arylide yellow and diarylide pigments. [8]

Use

Diketenes with two alkyl chains are used in the manufacture of paper for sizing of paper in order to improve their printability (by hydrophobization). Besides the rosin resins with about 60% share of world consumption, long chain diketenes called alkylketene dimers (AKD) are with 16% share the most important synthetic paper sizes, they are usually used in concentrations of 0.15%, meaning 1.5 kg solid AKD/t paper.

The preparation of AKD is carried out by chlorination of long chain fatty acids (such as stearic acid, using chlorinating agents such as thionyl chloride) to give the corresponding acid chlorides and subsequent elimination of HCl by amines (for example triethylamine) in toluene or other solvents: [9]

AKD synthesis 2.svg

Furthermore, diketenes are used as intermediates in the manufacture of pharmaceuticals, insecticides and dyes. For example pyrazolones are formed from substituted phenylhydrazines, they were used as analgetics but are now largely obsolete. With methylamine diketenes reacts to N,N'-dimethylacetoacetamide which is chlorinated with sulfuryl chloride and reacted with trimethyl phosphite to the highly toxic insecticide monocrotophos (especially toxic to bees). Diketenes react with substituted aromatic amines to acetoacetanilides, which are important precursors for mostly yellow, orange or red azo dyes and azo pigments.

Exemplary for the synthesis of arylides by the reaction of diketenes with aromatic amines is:

Acetoacetanilid from diketene.svg

Aromatic diazonium coupling with arylides to form azo dyes, such as Pigment Yellow 74:

Synthese von Brilliantgelb.svg

The industrial synthesis of the sweetener acesulfam-K is based on the reaction of diketene with sulfamic acid and cyclization by sulfur trioxide (SO3). [10]

Safety

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 adducts. [11]

Related Research Articles

<span class="mw-page-title-main">Amine</span> Chemical compounds and groups containing nitrogen with a lone pair (:N)

In chemistry, amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally 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, trimethylamine, and aniline. Inorganic derivatives of ammonia are also called amines, such as monochloramine.

<span class="mw-page-title-main">Ketene</span> Organic compound of the form >C=C=O

In organic chemistry, a ketene is an organic compound of the form RR'C=C=O, where R and R' are two arbitrary monovalent chemical groups. The name may also refer to the specific compound ethenone H2C=C=O, the simplest ketene.

<span class="mw-page-title-main">Acetoacetic acid</span> Chemical compound

Acetoacetic acid is the organic compound with the formula CH3COCH2COOH. It is the simplest beta-keto acid, and like other members of this class, it is unstable. The methyl and ethyl esters, which are quite stable, are produced on a large scale industrially as precursors to dyes. Acetoacetic acid is a weak acid.

In organic chemistry, a nitrile is any organic compound that has a −C≡N functional group. The name of the compound is composed of a base, which includes the carbon of the −C≡N, suffixed with "nitrile", so for example CH3CH2C≡N is called "propionitrile". The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons.

<span class="mw-page-title-main">Acyl halide</span> Oxoacid compound with an –OH group replaced by a halogen

In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.

Organochlorine chemistry is concerned with the properties of organochlorine compounds, or organochlorides, organic compounds containing at least one covalently bonded atom of chlorine. The chloroalkane class includes common examples. The wide structural variety and divergent chemical properties of organochlorides lead to a broad range of names, applications, and properties. Organochlorine compounds have wide use in many applications, though some are of profound environmental concern, with TCDD being one of the most notorious.

In chemistry, a dehydration reaction is a chemical reaction that involves the loss of water from the reacting molecule or ion. Dehydration reactions are common processes, the reverse of a hydration reaction.

<span class="mw-page-title-main">Sulfonic acid</span> Organic compounds with the structure R−S(=O)2−OH

In organic chemistry, sulfonic acid refers to a member of the class of organosulfur compounds with the general formula R−S(=O)2−OH, where R is an organic alkyl or aryl group and the S(=O)2(OH) group a sulfonyl hydroxide. As a substituent, it is known as a sulfo group. A sulfonic acid can be thought of as sulfuric acid with one hydroxyl group replaced by an organic substituent. The parent compound is the parent sulfonic acid, HS(=O)2(OH), a tautomer of sulfurous acid, S(=O)(OH)2. Salts or esters of sulfonic acids are called sulfonates.

<span class="mw-page-title-main">Benzoyl chloride</span> Organochlorine compound (C7H5ClO)

Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C7H5ClO. It is a colourless, fuming liquid with an irritating odour, and consists of a benzene ring with an acyl chloride substituent. It is mainly useful for the production of peroxides but is generally useful in other areas such as in the preparation of dyes, perfumes, pharmaceuticals, and resins.

<span class="mw-page-title-main">Azo dye</span> Class of organic compounds used as dye

Azo dyes are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl and substituted aryl groups. They are a commercially important family of azo compounds, i.e. compounds containing the C-N=N-C linkage. Azo dyes are synthetic dyes and do not occur naturally. Most azo dyes contain only one azo group but there are some that contain two or three azo groups, called "diazo dyes" and "triazo dyes" respectively. Azo dyes comprise 60-70% of all dyes used in food and textile industries. Azo dyes are widely used to treat textiles, leather articles, and some foods. Chemically related derivatives of azo dyes include azo pigments, which are insoluble in water and other solvents.

<span class="mw-page-title-main">Diazonium compound</span> Group of organonitrogen compounds

Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group [R−N+≡N]X− where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide.

In organic chemistry, an azo coupling is an reaction between a diazonium compound and another aromatic compound that produces an azo compound. In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile, and the activated carbon, serves as a nucleophile. Classical coupling agents are phenols and naphthols. Usually the diazonium reagent attacks at the para position of the coupling agent. When the para position is occupied, coupling occurs at a ortho position, albeit at a slower rate.

<span class="mw-page-title-main">Vinylacetylene</span> Chemical compound

Vinylacetylene is the organic compound with the formula C4H4. The colourless gas was once used in the polymer industry. It is composed of both alkyne and alkene groups and is the simplest enyne.

<span class="mw-page-title-main">Organolead chemistry</span>

Organolead chemistry is the scientific study of the synthesis and properties of organolead compounds, which are organometallic compounds containing a chemical bond between carbon and lead. The first organolead compound was hexaethyldilead (Pb2(C2H5)6), first synthesized in 1858. Sharing the same group with carbon, lead is tetravalent.

In inorganic chemistry, sulfonyl halide groups occur when a sulfonyl functional group is singly bonded to a halogen atom. They have the general formula RSO2X, where X is a halogen. The stability of sulfonyl halides decreases in the order fluorides > chlorides > bromides > iodides, all four types being well known. The sulfonyl chlorides and fluorides are of dominant importance in this series.

The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be effected by many reagents. The nitro group was one of the first functional groups to be reduced. Alkyl and aryl nitro compounds behave differently. Most useful is the reduction of aryl nitro compounds.

<span class="mw-page-title-main">Ethenone</span> Organic compound with the formula H2C=C=O

In organic chemistry, ethenone is the formal name for ketene, an organic compound with formula C2H2O or H2C=C=O. It is the simplest member of the ketene class. It is an important reagent for acetylations.

Ketene cycloadditions are the reactions of the pi system of ketenes with unsaturated compounds to provide four-membered or larger rings. [2+2], [3+2], and [4+2] variants of the reaction are known.

<span class="mw-page-title-main">Acetyl nitrate</span> Chemical compound

Acetyl nitrate is the organic compound with the formula CH3C(O)ONO2. It is classified as the mixed anhydride of nitric and acetic acids. It is a colorless explosive liquid that fumes in moist air.

<span class="mw-page-title-main">Alkyl ketene dimer</span> Class of chemical compounds

Alkyl ketene dimers (AKDs) are a family of organic compounds based on the 4-membered ring system of oxetan-2-one, which is also the central structural element of propiolactone and diketene. Attached to the oxetane ring of technically relevant alkyl ketene dimers there is a C12 – C16 alkyl group in the 3-position and a C13 – C17 alkylidene group in the 4-position.

References

  1. ↑ Beilstein E III/IV 17: 4297.
  2. ↑ Miller, Raimund; Abaecherli, Claudio; Said, Adel; Jackson, Barry (2001). "Ketenes". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a15_063. ISBN   978-3-527-30385-4.
  3. ↑ Susana Breda; Igor Reva; Rui Fausto (2012). "UV Induced Unimolecular Photochemistry of Diketene Isolated in Cryogenic Inert Matrices". J. Phys. Chem. A . 116 (9): 2131–2140. Bibcode:2012JPCA..116.2131B. doi:10.1021/jp211249k. PMID   22273010.
  4. ↑ Rafael Gómez-Bombarelli; Marina González-Pérez; María Teresa Pérez-Prior; José A. Manso; Emilio Calle; Julio Casado (2008). "Kinetic Study of the Neutral and Base Hydrolysis of Diketene". J. Phys. Org. Chem. 22 (5): 438–442. doi:10.1002/poc.1483.
  5. ↑ Arpe, Hans-Jürgen (2007), Industrielle organische Chemie: Bedeutende vor- und Zwischenprodukte (in German) (6th ed.), Weinheim: Wiley-VCH, pp. 200–1, ISBN   978-3-527-31540-6 [ permanent dead link ]
  6. ↑ Kiran Kumar Solingapuram Sai; Thomas M. Gilbert; Douglas A. Klumpp (2007). "Knorr Cyclizations and Distonic Superelectrophiles". J. Org. Chem. 72 (25): 9761–9764. doi:10.1021/jo7013092. PMID   17999519.
  7. ↑ Ashford's Dictionary of Industrial Chemicals, Third Edition, 2011, pages 3241-2.
  8. ↑ Hunger, K.; Herbst, W. (2012). "Pigments, Organic". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a20_371. ISBN   978-3527306732.
  9. ↑ Wolf S. Schultz: Sizing Agents in Fine Paper [ permanent dead link ] Retrieved 1 March 2012.
  10. ↑ EP 0218076 Process for the preparation of the non-toxic salts of 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-on-2,2-dioxide.
  11. ↑ Rafael Gómez-Bombarelli; Marina González-Pérez; María Teresa Pérez-Prior; José A. Manso; Emilio Calle; Julio Casado (2008). "Chemical Reactivity and Biological Activity of Diketene". Chem. Res. Toxicol. 21 (10): 1964–1969. doi:10.1021/tx800153j. PMID   18759502.
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