Dehydroacetic acid

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]

Dehydroacetic acid^[1]

Kekulé, skeletal formula of dehydroacetic acid
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 Y
3D model (JSmol)	Interactive image
Abbreviations	DHAA
ChEBI	CHEBI:137426
ChEMBL	ChEMBL284127 N
ChemSpider	10177 Y
ECHA InfoCard	100.007.541
EC Number	208-293-9
E number	E265 (preservatives)
MeSH	dehydroacetic+acid
PubChem CID	122903
UNII	2KAG279R6R Y
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 N Key: JEQRBTDTEKWZBW-UHFFFAOYSA-N 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). N verify (what is YN ?) Infobox references

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]