Diketen

Structural formula
General
Surname	Diketen
other names	4-methylene-2-oxetanone
Molecular formula	C 4 H 4 O 2
Brief description	Flammable, very reactive, colorless liquid with a pungent odor
External identifiers / databases
EC number	211-617-1
ECHA InfoCard	100.010.562
PubChem	12661
Wikidata	Q418541
properties
Molar mass	84.08 g mol −1
Physical state	liquid
density	1.09 g cm −3
Melting point	−7 ° C
boiling point	127 ° C
Vapor pressure	10 h Pa (20 ° C)
solubility	Decomposes in water
Refractive index	1.4379 (20 ° C)
safety instructions
H and P phrases	H: 226-302-330-315-318-335
	P: 210-260-280-303 + 361 + 353-304 + 340-305 + 351 + 338-308 + 310
Thermodynamic properties
ΔH f 0	−233.1 kJ / mol
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Diketene is the common name of the chemical compound 4-methylene-2-oxetanone from the group of lactones .

Extraction and presentation

Diketene is made by the dimerization of ketene . The dimerization takes place spontaneously at room temperature.

properties

Diketene is a very reactive, colorless liquid that is formed by the dimerization of ketene at room temperature and tends to polymerize spontaneously. It can be converted back into keten by heating.

Alkylated ketenes also readily dimerize to the correspondingly substituted diketenes.

Nucleophilic reaction of diketene

Diketene reacts easily with alcohols and amines to form derivatives of acetoacetic acid .

use

Diketene with two longer alkyl chains (so-called "ketene wax") is used in paper production for sizing ( hydrophobing ) paper to improve printability. In addition to the colophony resins with about 60% share of world consumption, the long-chain diketenes, also known as alkyl ketene dimers (AKD), with 16% share, are the most important synthetic paper sizing agents and are usually used in concentrations of 0.15%, i.e. H. 1.5 kg solid AKD / t paper used. AKD is produced by producing the acid chlorides of long-chain fatty acids - such as stearic acid - using, for example, thionyl chloride and subsequent elimination of HCl by tertiary amines - for example triethylamine - in toluene , other solvents, or in bulk without solvents. The monomeric ketene formed first quickly dimerizes to the diketene.

Synthesis of alkyl ketene dimer (AKD)

Diketene is also used as an intermediate in the manufacture of pharmaceuticals, insecticides and dyes. With substituted phenylhydrazines, the pyrazolones, which are now largely obsolete as analgesics, are created . Diketene reacts with methylamine to form methylacetoacetamide, which is chlorinated with sulfuryl chloride and converted with trimethyl phosphite to form the highly toxic (especially for bees) insecticide monocrotophos . Diketene reacts with substituted aromatic amines to form acetoacetanilides (arylides), which are important precursors for mostly yellow, orange or red azo dyes and azo pigments .

The preparation of acetoacetanilide is an example of the synthesis of arylides by reacting diketene with aromatic amines :

Acetoacetanilide from Diketene - Synthesis of Arylides

Aromatic diazonium compounds couple with arylides to form azo dyes, such as. B. Brilliant Yellow (Pigment Yellow 74).

Synthesis of Pigment Yellow 74

The industrial synthesis of the sweetener acesulfame-K is based on the conversion of diketene with amidosulfonic acid and cyclization using SO ₃

safety instructions

The vapors of 4-methylene-2-oxetanone can form an explosive mixture with air ( flash point 33 ° C, ignition temperature 275 ° C).

literature

Beilstein E III / IV 17: 4297 ff

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on 4-methylene-2-oxetanone in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-186.
↑ Entry on But-3-en-3-olide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-25.
↑ Andreas Pingel Keuth: Paper manufacture: From cellulose to filter bags, writing paper, ... In: Chemistry in our time . 39, 6, Wiley-VCH, Weinheim 2005, pp. 403-409. DOI: 10.1002 / ciuz.200500234
↑ Patent USUS5344943A : Long-chain ketene dimers. Applied December 30, 1991 , published December 29, 1992 , applicant: Akzo Nobel NV, inventor: Nils Brolund. ‌
↑ Wolf S. Schultz: Sizing Agents in Fine Paper.Retrieved March 1, 2012.
↑ G. Heckmann, F. Previdoli, T. Riedel, D. Ruppen, D. Veghini, U. Zacher: Process development and production concepts for the manufacturing of organic fine chemicals . In: CHIMIA . tape 60 , no. 9 , 2006, p. 530-533 , doi : 10.2533 / chimia.2006.530 .
↑ Patent EP0218076B1 : Process for the production of the non-toxic salts of 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one-2,2-dioxide. Filed on Aug. 27, 1986 , published on January 3, 1990 , Applicant: Hoechst , inventors Dieter Reusch Ling, Adolf Linkies et al ..

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on 4-methylene-2-oxetanone in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .

[CRC90_3_186-2] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-186.

[CLP_100.010.562-3] Entry on But-3-en-3-olide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[CRC90_5_25-4] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-25.

[5] Andreas Pingel Keuth: Paper manufacture: From cellulose to filter bags, writing paper, ... In: Chemistry in our time . 39, 6, Wiley-VCH, Weinheim 2005, pp. 403-409. DOI: 10.1002 / ciuz.200500234

[6] Patent USUS5344943A : Long-chain ketene dimers. Applied December 30, 1991 , published December 29, 1992 , applicant: Akzo Nobel NV, inventor: Nils Brolund. ‌

[7] Wolf S. Schultz: Sizing Agents in Fine Paper.Retrieved March 1, 2012.

[8] G. Heckmann, F. Previdoli, T. Riedel, D. Ruppen, D. Veghini, U. Zacher: Process development and production concepts for the manufacturing of organic fine chemicals . In: CHIMIA . tape 60 , no. 9 , 2006, p. 530-533 , doi : 10.2533 / chimia.2006.530 .

[9] Patent EP0218076B1 : Process for the production of the non-toxic salts of 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one-2,2-dioxide. Filed on Aug. 27, 1986 , published on January 3, 1990 , Applicant: Hoechst , inventors Dieter Reusch Ling, Adolf Linkies et al ..