Butylated hydroxytoluene (CAS 128-37-0) — Woody N/A Note Fragrance Ingredient
Butylated hydroxytoluene
CAS 128-37-0
What Is Butylated hydroxytoluene?
Butylated hydroxytoluene (BHT) is a synthetic antioxidant commonly found in processed foods, cosmetics, and pharmaceuticals. It prevents rancidity by inhibiting oxidation. While ubiquitous in consumer products, BHT has sparked debate about its safety profile at high concentrations, making it a regulated ingredient in many applications.
Safety Profile
USE WITH AWARENESSWhat Does Butylated hydroxytoluene Smell Like?
BHT has a faint phenolic odor reminiscent of old books or printer ink. Its scent profile is dry and slightly medicinal, with a waxy undertone that lingers subtly. In formulations, it behaves more as a stabilizer than a fragrance note, though it can contribute a faintly chemical top note that dissipates quickly.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
N/A
2D Molecular Structure
SMILES: CC1=CC(=C(O)C(=C1)C(C)(C)C)C(C)(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
BHT is a synthetic phenolic antioxidant belonging to the class of hindered phenols. It is produced industrially by the alkylation of p-cresol with isobutylene. The molecule’s effectiveness comes from its ability to donate hydrogen atoms to free radicals, terminating oxidation chain reactions. Its symmetrical structure and tert-butyl groups provide steric hindrance that enhances stability.
Physical & Chemical Properties
| Boiling Point | 265 °C |
|---|---|
| Melting Point | 70 °C |
| Density | 1.048 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Food Preservation | 0.02% | Up to 0.1% | Prevents rancidity in fats and oils |
| Cosmetics | 0.1% | Up to 0.5% | Antioxidant in creams and lipsticks |
Classic Accords
Tip: Use minimal quantities as stabilizer rather than fragrance component.
Alternatives & Comparisons
Natural antioxidant alternative derived from vitamin E, preferred in clean beauty formulations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted by IFRA but subject to regional limits in food and cosmetic applications.
EU Allergen Declaration
Not classified as an EU allergen.
GHS Classification
RIFM Assessment
RIFM has evaluated BHT as safe at current use levels in fragrances.
Sustainability
As a petrochemical derivative, BHT raises sustainability concerns. Manufacturers are increasingly replacing it with plant-derived antioxidants in response to consumer demand for cleaner ingredients. Proper disposal is required to prevent environmental persistence.
Explore Butylated hydroxytoluene
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References
- PubChem. Butylated hydroxytoluene. PubChem CID 31404
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 128-37-0Physical Properties
| Molecular Weight | 220.35 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 5.3🔬 PubChem |
| Boiling Point | 265 °C🔬 EPA CompTox |
| Vapor Pressure | 0.01 mmHg @ 25°C📊 OPERA |
| Flash Point | 126.7 °C🔬 EPA CompTox |
| Involatility Index | 0.0007💻 Calculated |
| log Kp (skin permeability) | -0.281💻 Calculated |
| SMILES | CC1=CC(=C(C(=C1)C(C)(C)C)O)C(C)(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | citruswoody• leffingwell |
| Functional Groups | phenolaromatic💻 RDKit |
| 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. BHT has a very faint, musty, occasional cresylictype odor. BHA and BHT are extensively used in foods as antioxidants. Most fats, oils and fat-containing foods are naturally susceptible to rapid rancification and other oxidative reactions that produce compounds having objectionable taste and odor, making foods containing them unpalatable. Lipid oxidation is autocatalytic and proceeds as a complex of chain reactions, the nature and speed of which vary with the substrate, temperature, light, availability of oxygen and presence or absence of oxidation catalysts. Antioxidants like BHT act as “chain breaks” in the autooxidation processes under the usual conditions of processing, storage and use of fat-containing foods (Burdock, 1997).📖 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: DTXSID2020216
Physical Properties
| Molecular Weight | 220.356 g/mol🔬 EPA CompTox |
| Density | 0.986 g/cm^3🔬 EPA CTX |
| Boiling Point | 265.167 °C🔬 EPA CTX |
| Melting Point | 70.384 °C🔬 EPA CTX |
| Flash Point | 124.518 °C🔬 EPA CTX |
| Refractive Index | 1.499 Dimensionless📊 OPERA |
| Molar Volume | 237.514 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 5.007 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 5.086 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 5.086 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 9.29 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.003 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.011 mmHg🔬 EPA CTX |
| Surface Tension | 30.031 dyn/cm📊 OPERA |
| Thermal Conductivity | 111.008 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 20.23 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 69.734 cm^3/mol📊 OPERA |
| Polarizability | 27.645 Å^3📊 OPERA |
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.
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