Butylated hydroxyanisole (CAS 25013-16-5) — Woody Non-olfactive Note Fragrance Ingredient
Butylated hydroxyanisole
CAS 25013-16-5
What Is Butylated hydroxyanisole?
Butylated hydroxyanisole (BHA) is a synthetic antioxidant commonly found in processed foods, cosmetics, and pharmaceuticals to prevent rancidity. It extends product shelf life by inhibiting oxidative degradation of fats and oils. While effective, BHA’s use in fragrances is limited due to its weak odor profile and primary function as a preservative rather than a scent contributor. Its presence matters because it demonstrates how non-fragrance chemicals play crucial roles in product stability, though perfumers must balance preservation needs with olfactory impact.
Safety Profile
USE WITH AWARENESSWhat Does Butylated hydroxyanisole Smell Like?
BHA has a faint, slightly phenolic odor reminiscent of stale wax or old candles, with subtle medicinal undertones. It lacks the complexity of traditional fragrance ingredients, presenting more as a background chemical note than a deliberate scent. In formulations, its odor is usually masked by other components. The dry-down reveals barely perceptible waxy nuances that dissipate quickly, making it functionally odor-neutral in most applications where preservation is the primary goal.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
2D Molecular Structure
SMILES: COC1=CC=C(O)C=C1.CC(C)(C)* |c:7,t:2,4,lp:1:2,6:2,m:13:8.7|
Chemistry, Properties & Perfumer Guide
The Chemistry
Butylated hydroxyanisole is a synthetic phenolic compound derived from 4-methoxyphenol. It functions as a radical scavenger, interrupting the autoxidation chain reaction in fats. Industrially produced by alkylation of hydroquinone with isobutylene, it exists as a mixture of two isomers (2-BHA and 3-BHA). The ortho-isomer (3-BHA) shows greater antioxidant activity due to steric hindrance at the phenolic oxygen. Its efficacy increases synergistically when combined with butylated hydroxytoluene (BHT) or citric acid in chelating systems.
Physical & Chemical Properties
| Boiling Point | N/A |
|---|---|
| Melting Point | 48-55 °C |
| Flash Point | N/A |
| Density | N/A |
| Vapor Pressure | N/A |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Food Preservation | 0.02% | Up to 0.1% | Primary antioxidant function |
| Cosmetics | 0.1-0.5% | Up to 1% | Prevents oil rancidity |
| Pharmaceuticals | 0.005-0.1% | As needed | Stabilizes formulations |
Classic Accords
Tip: Use minimal effective concentrations to avoid potential sensitization while achieving preservation goals.
Alternatives & Comparisons
Another synthetic antioxidant with similar functionality but different regulatory status and solubility profile.
Natural vitamin E antioxidants preferred in clean-label formulations despite lower efficacy.
Plant-derived antioxidant complex offering natural preservation with additional aromatic benefits.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not directly restricted by IFRA but use may be limited by end-product regulations.
EU Allergen Declaration
Not classified as an EU allergen.
GHS Classification
RIFM Assessment
RIFM has evaluated BHA primarily for its antioxidant rather than fragrance use, with recommendations to minimize skin contact.
Sustainability
As a petrochemical derivative, BHA’s production carries typical environmental burdens of synthetic organics. While effective at low doses, some markets are shifting toward naturally derived antioxidants due to regulatory and consumer preference pressures. Proper disposal is required to prevent aquatic contamination given its phenolic structure.
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References
- National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 31404. PubChem BHA
- EFSA Panel on Food Additives (2011). Scientific Opinion on the re-evaluation of butylated hydroxyanisole – BHA (E 320) as a food additive. EFSA Journal. EFSA Assessment
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 25013-16-5Physical Properties
| Molecular Weight | 180.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.2🔬 PubChem |
| Boiling Point | 263.9 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0025 mmHg @ 25°C📊 OPERA |
| Flash Point | 156.1 °C🔬 EPA CompTox |
| Involatility Index | 0.0002💻 Calculated |
| log Kp (skin permeability) | -1.527💻 Calculated |
| SMILES | CC(C)(C)C1=C(C=CC(=C1)OC)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 4.9 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | balsamicwoody• leffingwell |
| Functional Groups | phenoletheraromatic💻 RDKit |
| “Very faint phenolic type odor.”📖 Arctander | |
| BHA and BHT (butylated hydroxytoluene) are monohydric phenolic antioxidants that, prior to their introduction and acceptance in the food industry, were used to protect petroleum against oxidative degumming. Chemically, BHA is a mixture of two isomers, 3tertiary-butyl-4-hydroxyanisole (90%) and 2-tertiary-butyl-4-hydroxyanisole (10%). Both BHA and BHT assert a good carry-through effect, although BHA is slightly better than BHT in this respect. BHT is, however, more effective in suppressing oxidation of animal fats than vegetable oils. Among its multiple applications, BHA is particularly useful in protecting the flavors and color of essential oils and is considered the most effective of all food-approved antioxidants for this application. BHA is particularly effective in controlling the oxidation of short-chain fatty acids, such as those found in coconut and palm kernel oils that are used typically in cereal and confectionary products.📖 Fenaroli | |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID7020215
Physical Properties
| Molecular Weight | 180.24 g/mol🔬 PubChem |
| Density | 0.678 g/cm^3🔬 EPA CTX |
| Boiling Point | 268 °C🔬 EPA CTX |
| Melting Point | 52.877 °C🔬 EPA CTX |
| Flash Point | 138.601 °C🔬 EPA CTX |
Partition & Solubility
| LogP (Octanol-Water) | 1.91 Log10 unitless🔬 EPA CTX |
| Water Solubility | 0.01 mol/L🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.002 mmHg🔬 EPA CTX |
Molecular Descriptors
| Topological Polar Surface Area | 29.46 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 53.36 cm^3/mol💻 Computed |
Data Sources:
🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.
