Dehydroacetic acid

Dehydroacetic acid^[1]
Names
	Preferred IUPAC name 3-Acetyl-2-hydroxy-6-methyl-4H-pyran-4-one
	Other names Biocide 470F[citation needed]; Methylacetopyronone[citation needed]
Identifiers
CAS Number	520-45-6 ;
3D model (JSmol)	Interactive image;
Abbreviations	DHAA
ChEBI	CHEBI:137426;
ChEMBL	ChEMBL284127 ;
ChemSpider	10177 ;
ECHA InfoCard	100.007.541
EC Number	208-293-9;
E number	E265 (preservatives)
MeSH	dehydroacetic+acid
PubChem CID	122903;
UNII	2KAG279R6R ;
CompTox Dashboard (EPA)	DTXSID801015814 DTXSID6020014, DTXSID801015814 ;
	InChI InChI=1S/C8H8O4/c1-4-3-6(10)7(5(2)9)8(11)12-4/h3,11H,1-2H3 Key: JEQRBTDTEKWZBW-UHFFFAOYSA-N ;
	SMILES CC(=O)C1=C(O)OC(C)=CC1=O;
Properties
Chemical formula	C8H8O4
Molar mass	168.148 g·mol−1
Appearance	White crystals
Melting point	109 °C; 228 °F; 382 K
Boiling point	270 °C; 518 °F; 543 K
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302
Precautionary statements	P264, P270, P301+P312, P330, P501
NFPA 704 (fire diamond)	1 1 0
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Dehydroacetic acid is an organic compound which has several industrial applications. The compound is classified as a pyrone derivative. It presents as an odorless, colorless to white crystalline powder, almost insoluble in water and moderately soluble in most organic solvents.^[2]

Preparation

It is prepared by the base-catalysed dimerization of diketene.^[3] Commonly used organic bases include imidazole, DABCO, and pyridine.^[4]

Uses

Industrially, dehydroacetic acid has several uses which include the following:

as a fungicide and bactericide. The sodium salt, sodium dehydroacetate, is often used in place of dehydroacetic acid because of its greater solubility in water.
as a food preservative to prevent pickle bloating in squash and strawberries.^[5] When used as a food additive, dehydroacetic acid is referred to using the International Numbering System for Food Additives or E number 265.
as a plasticizer in synthetic resins.^[1]
as an antienzyme in toothpastes.
as a precursor for dimethyl-4-pyridones. The compounds are synthesized when dehydroacetic acid is exposed to aqueous solutions containing primary amines.^[6]

References

^ ^a ^b Merck Index, 11th Edition, 2855
^ Jilalat, Alae Eddine; et al. (2017). "DEHYDROACETIC ACID (Part 1): CHEMICAL AND PHARMACOLOGICAL PROPERTIES". Journal Marocain de Chimie Hétérocyclique. 16 (1): 1–47. ISSN 1114-7792. Retrieved July 3, 2017.
^ Raimund Miller, Claudio Abaecherli, Adel Said, Barry Jackson. "Ketenes". In Ullmann's Encyclopedia of Industrial Chemistry. 2001, Wiley-VCH, Weinheim. doi:10.1002/14356007.a15_063
^ Clemens, Robert J.; Witzeman, J. Stewart (1993). Agreda, Victor H.; Zoeller, Joseph R. (eds.). Acetic Acid and its Derivatives. New York: Marcel Dekker, Inc. p. 202. ISBN 9780824787929.
^ Harold William Rossmoore. Handbook of Biocide and Preservative Use, p. 341. ISBN 0-7514-0212-5
^ Cook, Denys (1963). "The Preparation, Properties, and Structure of 2,6-bis-(Alkyamino)-2,5-heptadien-4-ones". Canadian Journal of Chemistry. 41 (6): 1435–1440. doi:10.1139/v63-195.

[Merck-1] Merck Index, 11th Edition, 2855

[2] Jilalat, Alae Eddine; et al. (2017). "DEHYDROACETIC ACID (Part 1): CHEMICAL AND PHARMACOLOGICAL PROPERTIES". Journal Marocain de Chimie Hétérocyclique. 16 (1): 1–47. ISSN 1114-7792. Retrieved July 3, 2017.

[3] Raimund Miller, Claudio Abaecherli, Adel Said, Barry Jackson. "Ketenes". In Ullmann's Encyclopedia of Industrial Chemistry. 2001, Wiley-VCH, Weinheim. doi:10.1002/14356007.a15_063

[4] Clemens, Robert J.; Witzeman, J. Stewart (1993). Agreda, Victor H.; Zoeller, Joseph R. (eds.). Acetic Acid and its Derivatives. New York: Marcel Dekker, Inc. p. 202. ISBN 9780824787929.

[5] Harold William Rossmoore. Handbook of Biocide and Preservative Use, p. 341. ISBN 0-7514-0212-5

[6] Cook, Denys (1963). "The Preparation, Properties, and Structure of 2,6-bis-(Alkyamino)-2,5-heptadien-4-ones". Canadian Journal of Chemistry. 41 (6): 1435–1440. doi:10.1139/v63-195.

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