520-45-6 Usage
Chemical Properties
Dehydroacetic acid is a white to cream-coloured powder that is only very slightly soluble in water (less than 0.1 %). However, the sodium salt hydrate (CSH7Na04.H20) has a solubility of 33% in water at 25°C, and 48% in propylene glycol. The acid is 22% soluble in acetone, 18% in benzene, and I g dissolves in about 35 ml of ethanol.It is used to reduce pickle bloating, and as a pesticide and preservative for squash and strawberries. Its permissible use level is 65ppm.Dehydroacetic acid is one of the food additives found in red wine and was determined by ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS).To assay dehydroacetic acid, add 500 mg to a 250-ml Erlenmeyer flask and dissolve in 75 ml of neutral alcohol. Following the addition of phenolphthalein T.S., titrate with 0.1 N NaOH to a pink end-point that persists for at least 30 s. Each ml of 0.1 N NaOH = 16.82 mg of dehydroacetic acid (National Academy of Sciences, 1963).Dehydroacetic acid is a synthetic chemical (no plant-based preservatives that meet our efficacy standards currently exist) that is considered to be a low hazard for human health and for the environment.
Uses
Different sources of media describe the Uses of 520-45-6 differently. You can refer to the following data:
1. Dehydroacetic acid (DHS) is used as stabilizer for cosmetic and pharmaceutical products due to its fungicide and bactericide activity, as additive for PVC-stabilizers and for the syntheses of veterinary medicines. Product Data Sheet
2. Geogard(R) 111a preservative is based on dehydroacetic acid (DHA) and therefore are recognized by major cosmetic, toiletry and fragrance regulatory authorities worldwide for use in cosmetic and personal care products.
3. Geogard(R) 221 preservative is based on dehydroacetic acid (DHA) and benzyl alcohol, and therefore is recognized by major cosmetic, toiletry and fragrance regulatory authorities worldwide for use in cosmetic and personal care products.
4. Geogard(R) 361 preservative is based on six synergistic components, all with wide global regulatory acceptance: dehydroacetic acid (DHA); salicylic acid; benzoic acid; phenoxyethanol; benzyl alcohol; and benzethonium chloride.
5. antifungal, antibacterial
6. dehydroacetic acid is a preservative with low sensitizing potential. This is a weak acid used as a fungi-and bacteria-destroying agent in cosmetics. The presence of organic matter decreases its effective ness. It is not irritating or allergy causing when applied on the skin.
7. Dehydroacetic Acid (DHA) is a preservative that is a crystalline powder with a solubility of less than 0.1 g in 100 g of water at 25°C. It can undergo a variety of chemical reactions which give it utility in many applications. It is used at 0.01–0.5% for microbiological growth inhibition in various foods. It is used for cut or peeled squash, with no more than 65 ppm remaining in or on the prepared squash.
Synthesis Reference(s)
The Journal of Organic Chemistry, 49, p. 5105, 1984 DOI: 10.1021/jo00200a018
General Description
Dehydroacetic acid is a pyrone derivative, that is typically synthesized by the base-catalyzed dimerization of diketene. It is used as a preservative in pharmaceutical, food and cosmetic products.Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.
Flammability and Explosibility
Notclassified
Safety Profile
Poison by ingestion.
Moderately toxic by intraperitoneal route.
Questionable carcinogen with experimental
tumorigenic data. Combustible when
exposed to heat or flame. When heated to
decomposition it emits acrid smoke and
irritating fumes.
Check Digit Verification of cas no
The CAS Registry Mumber 520-45-6 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 5,2 and 0 respectively; the second part has 2 digits, 4 and 5 respectively.
Calculate Digit Verification of CAS Registry Number 520-45:
(5*5)+(4*2)+(3*0)+(2*4)+(1*5)=46
46 % 10 = 6
So 520-45-6 is a valid CAS Registry Number.
InChI:InChI=1/C8H8O4/c1-4-3-6(10)7(5(2)9)8(11)12-4/h3,7H,1-2H3
520-45-6Relevant articles and documents
Sodium carbonate as a solid-phase reagent for the generation of acetylketene
Bell, Kelcey,Sadasivam, Dhandapani V.,Gudipati, Indra Reddy,Ji, Hua,Birney, David
body text, p. 1295 - 1297 (2009/09/06)
Reaction of a toluene solution of 3-oxobutanoyl chloride (14) with Na2CO3 in the presence of a catalytic amount of triethylamine at -78 °C generates a solution of acetylketene (2), the dimer of which was isolated. Acetylketene (2) was trapped with 2-propanone, 2-propanol, and ethyl vinyl ether.
Gas-Phase Kinetics of Elimination Reactions of Pentane-2,4-Dione Derivatives
Al-Awadi, Nouria A.,El-Nagdi, Mohamed H.,Mathew, Tommy
, p. 517 - 524 (2007/10/02)
Gas-phase elimination reactions of pentane-2,4-dione, methyl acetoacetate, ethyl acetoacetate, 3-phenylhydroazopentane-2,4-dione, and ethyl 3-oxo-2-phenylhydrazonobutyrate have been measured in the temperature ranges of 744-783, 662-695, 614-663, 604-664, and 503-555 K, respectively, using a flow-thermolysis technique.These compounds undergo unimolecular first-order elimination reactions, for which log A = 11.9, 11.2, 11.7, 11.5, and 11.7 s-1 and Ea = 198.3, 167.1, 141.7, 165.6, and 141.7 kJ mol-1, respectively.The kinetic data and product analysis shows that the reactions are highly affected by the electronic nature of the substituents at the carbonyl and methylene carbon atoms of the substrates investigated.
