2-tert-Butyl-4-methoxyphenol (CAS 121-00-6) — Balsamic Base Note Fragrance Ingredient
2-tert-Butyl-4-methoxyphenol
CAS 121-00-6
What Is 2-tert-Butyl-4-methoxyphenol?
2-tert-Butyl-4-methoxyphenol is a synthetic antioxidant commonly used in food, cosmetics, and fragrances to prevent oxidation. It’s often listed as BHA (butylated hydroxyanisole) on product labels. This ingredient helps extend shelf life by protecting against rancidity and spoilage in oils and fats.
Safety Profile
USE WITH AWARENESSWhat Does 2-tert-Butyl-4-methoxyphenol Smell Like?
2-tert-Butyl-4-methoxyphenol has a faint phenolic odor with waxy, slightly medicinal undertones. In fragrance applications, it contributes a subtle stabilizing effect rather than a dominant scent profile. At higher concentrations, it can impart a characteristic phenolic sharpness that requires careful balancing with other ingredients.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as an antioxidant stabilizer to preserve the delicate aldehyde notes and prevent rancidity in the floral bouquet.
Helps maintain the integrity of the vanilla base notes against oxidation in this classic oriental fragrance.
2D Molecular Structure
SMILES: COC1=CC=C(O)C(=C1)C(C)(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
2-tert-Butyl-4-methoxyphenol belongs to the phenol class of synthetic antioxidants. It’s produced through the alkylation of p-methoxyphenol with isobutylene. The tert-butyl group provides steric hindrance that enhances its antioxidant properties. This compound demonstrates excellent radical scavenging capabilities, particularly in lipid systems where it donates hydrogen atoms to terminate oxidation chain reactions.
Physical & Chemical Properties
| Boiling Point | 264-270 °C |
|---|---|
| Melting Point | 48-55 °C |
| Flash Point | >110 °C |
| Density | 1.06 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.5% | Primarily as stabilizer |
| Cosmetics | 0.01-0.1% | Up to 0.5% | Antioxidant protection |
Classic Accords
Tip: Use at minimum effective concentration to prevent any phenolic off-notes in delicate compositions.
Alternatives & Comparisons
Alternative synthetic antioxidant with similar properties but different molecular structure and solubility profile.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA, but usage should follow general antioxidant guidelines.
GHS Classification
RIFM Assessment
RIFM has evaluated this material and recommends following standard safety guidelines for phenolic compounds.
Sustainability
As a synthetic material, 2-tert-Butyl-4-methoxyphenol is produced through petrochemical processes. While effective at low concentrations, its environmental persistence requires careful disposal considerations. Some manufacturers are developing more biodegradable antioxidant alternatives.
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References
- 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 Journal 2011
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID7040788
Physical Properties
| Molecular Weight | 180.247 g/mol🔬 EPA CompTox |
| Density | 0.79 g/cm^3🔬 EPA CTX |
| Boiling Point | 268 °C🔬 EPA CTX |
| Melting Point | 54.7 °C🔬 EPA CTX |
| Flash Point | 127.886 °C🔬 EPA CTX |
| Refractive Index | 1.508 Dimensionless📊 OPERA |
| Molar Volume | 178.553 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.9 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.169 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.169 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.78 Log10 unitless📊 OPERA |
| Water Solubility | 0.005 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.002 mmHg🔬 EPA CTX |
| Viscosity | 5.025 cP📊 OPERA |
| Surface Tension | 32.878 dyn/cm📊 OPERA |
| Thermal Conductivity | 130.559 mW/(m*K)📊 OPERA |
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 | 53.2 cm^3/mol📊 OPERA |
| Polarizability | 21.09 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.
