Dehydroacetic Acid is a well-established specialty cosmetic ingredient used as a preservative. It belongs to the pyran-2,4-dione chemical family and is identified by CAS 520-45-6, EC 208-293-9, molecular formula C₈H₈O₄, and molecular weight 168.15 g/mol.
The ingredient is particularly relevant to cosmetic and personal-care formulations where controlled preservation is required. Its suitability depends on formulation composition, concentration, pH, processing conditions and the regulations applicable to the target market.
Dehydroacetic Acid is chemically described as 3-acetyl-6-methylpyran-2,4(3H)-dione. It is also known as 3-acetyl-6-methyl-2H-pyran-2,4(3H)-dione and Methylacetopyronone.
Unlike parabens such as methylparaben, propylparaben and butylparaben, Dehydroacetic Acid is structurally different and belongs to a pyran-dione class of compounds.
Dehydroacetic Acid is listed in European cosmetic ingredient and preservative documentation as a preservative. The EU cosmetic framework specifically identifies Dehydroacetic Acid and its salts under preservative entry 13.
This makes Dehydroacetic Acid an important ingredient for manufacturers and formulators evaluating preservation systems for personal-care products.
| Property | Value |
|---|---|
| Chemical Name | 3-Acetyl-6-methylpyran-2,4(3H)-dione |
| CAS Number | 520-45-6 |
| EC Number | 208-293-9 |
| Molecular Formula | C₈H₈O₄ |
| Molecular Weight | 168.15 g/mol |
| Chemical Class | Pyran-2,4-dione |
| IUPAC Name | 3-Acetyl-6-methylpyran-2,4-dione |
These chemical identity values are documented by PubChem and European regulatory records.
Published chemical data report a melting point of approximately 109–111°C, with the material reported to sublime. PubChem also reports very limited water solubility at 25°C, while providing higher solubility in certain organic solvents.
For an SDP commercial specification, the actual approved melting-point and solubility requirements should be used instead of automatically adopting literature values.
Dehydroacetic Acid has very low solubility in water. PubChem's referenced data report less than 0.1% solubility in water at 25°C, while higher solubility is reported in solvents including acetone and methanol.
This characteristic is important during formulation development. Formulators should select an appropriate incorporation method and evaluate the compatibility of the ingredient with the complete formulation system.
Dehydroacetic Acid is recognized in the EU cosmetic ingredient framework as a preservative. The European regulatory ingredient inventory also identifies its function as preservative.
Preservative performance depends on the finished formulation rather than the ingredient alone. Factors such as pH, concentration, water activity, packaging, manufacturing hygiene and interaction with other formulation ingredients should be evaluated.
When using Dehydroacetic Acid as a cosmetic ingredient, formulators should consider:
Appropriate formulation and preservative-efficacy testing should be completed before commercialization.
The EU Cosmetics Regulation lists Dehydroacetic Acid and sodium dehydroacetate under preservative entry 13. The listed maximum concentration is 0.6% as acid, with the condition that it is not to be used in aerosol dispensers (sprays).
Therefore, the product page can accurately describe Dehydroacetic Acid as a regulated cosmetic preservative ingredient, but the regulatory limit should not be presented as a universal worldwide usage limit. Cosmetic regulations vary by market and can be amended over time.
A commercial Dehydroacetic Acid Cosmetic Ingredient should be evaluated against an approved specification. Depending on the product specification, quality control can include:
Numerical acceptance criteria should come from the current SDP specification and COA.
Dehydroacetic Acid should be stored according to the approved product specification and SDS.
General storage practices include:
| Parameter | Specification |
|---|---|
| Appearance | White or colourless crystals / white powder |