Dehydroacetic acid
{{missing information|etymology/history of discovery (where does the dehydro come from?); biocide mechanism of action; pKa|date=August 2022}}
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 450974443
| Reference = Merck Index, 11th Edition, 2855
| ImageFile = Dehydroacetic acid.svg
| ImageFile_Ref = {{chemboximage|correct|??}}
| ImageSize = 150px
| ImageName = Kekulé, skeletal formula of dehydroacetic acid
| PIN = 3-Acetyl-2-hydroxy-6-methyl-4H-pyran-4-one
| OtherNames = Biocide 470F{{Citation needed|date = October 2011}}
Methylacetopyronone{{Citation needed|date = October 2011}}
|Section1={{Chembox Identifiers
| Abbreviations = DHAA
| CASNo = 520-45-6
| CASNo_Ref = {{cascite|correct|CAS}}
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 284127
| ChEBI = 137426
| PubChem = 122903
| ChemSpiderID = 10177
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| UNII = 2KAG279R6R
| UNII_Ref = {{fdacite|correct|FDA}}
| EINECS = 208-293-9
| MeSHName = dehydroacetic+acid
| SMILES = CC(=O)C1=C(O)OC(C)=CC1=O
| StdInChI = 1S/C8H8O4/c1-4-3-6(10)7(5(2)9)8(11)12-4/h3,11H,1-2H3
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = JEQRBTDTEKWZBW-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
}}
|Section2={{Chembox Properties
| C=8 | H=8 | O=4
| Appearance = White crystals
| Density=
| MeltingPtK = 382
| BoilingPtK = 543
}}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|302}}
| PPhrases = {{P-phrases|264|270|301+312|330|501}}
| NFPA-H = 1
| NFPA-F = 1
| NFPA-R = 0
}}
}}
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.{{cite journal |last1=Jilalat |first1=Alae Eddine |display-authors=etal |date=2017 |title=DEHYDROACETIC ACID (Part 1): CHEMICAL AND PHARMACOLOGICAL PROPERTIES |url=http://revues.imist.ma/index.php?journal=JMCH&page=article&op=view&path%5B%5D=8199 |journal=Journal Marocain de Chimie Hétérocyclique |volume=16 |issue=1 |pages=1–47 |issn= 1114-7792|access-date= July 3, 2017}}
Preparation
It is prepared by the base-catalysed dimerization of diketene.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}} Commonly used organic bases include imidazole, DABCO, and pyridine.{{cite book|last1=Clemens|first1=Robert J.|last2=Witzeman|first2=J. Stewart|editor1-last=Agreda|editor1-first=Victor H.|editor2-last=Zoeller|editor2-first=Joseph R.|title=Acetic Acid and its Derivatives|date=1993|publisher=Marcel Dekker, Inc.|location=New York|isbn=9780824787929|page=202|url=https://books.google.com/books?id=3MjdGp1v1YIC&pg=PA202}}
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.Harold William Rossmoore. Handbook of Biocide and Preservative Use, p. 341. {{ISBN|0-7514-0212-5}} 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.
- 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.{{cite journal |last1=Cook |first1=Denys |title=The Preparation, Properties, and Structure of 2,6-bis-(Alkyamino)-2,5-heptadien-4-ones |journal=Canadian Journal of Chemistry |date=1963 |volume=41 |issue=6 |pages=1435–1440 |doi=10.1139/v63-195|doi-access=free }}