2-Isopropyl-p-cresol (CAS 4427-56-9) — Woody Middle Note Fragrance Ingredient
2-Isopropyl-p-cresol
CAS 4427-56-9
What Is 2-Isopropyl-p-cresol?
2-Isopropyl-p-cresol is a synthetic fragrance ingredient used in perfumery for its woody, spicy character. It’s found in niche fragrances and some masculine-leaning compositions. This molecule contributes depth and warmth to fragrance formulas, often used as a modifier for woody accords.
Safety Profile
USE WITH AWARENESSWhat Does 2-Isopropyl-p-cresol Smell Like?
2-Isopropyl-p-cresol presents a dry, woody aroma with distinct spicy undertones reminiscent of aged cedar and clove. The initial impression is sharp and phenolic, evolving into a smoother heart with leathery facets. In dry-down, it reveals a persistent warmth that blends well with amber bases. The character is more refined than crude cresols, with less medicinal harshness.
2D Molecular Structure
SMILES: CC(C)C1=C(O)C=CC(C)=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Isopropyl-p-cresol belongs to the alkylphenol class, synthesized through Friedel-Crafts alkylation of p-cresol with isopropyl alcohol. The isopropyl group at the 2-position creates steric hindrance that modifies both reactivity and odor profile compared to simpler cresols. Industrial production typically uses acid catalysts like aluminum chloride.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Approx. 230-235 °C (estimated) |
| Density | Approx. 0.95-1.00 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Woody-spicy modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Leather accord component |
Classic Accords
Tip: Use in trace amounts to add phenolic complexity to woody bases without overwhelming the composition.
Alternatives & Comparisons
Herbal-thymic alternative with similar phenolic structure but different odor profile.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under current IFRA standards (Amendment 49).
GHS Classification
RIFM Assessment
Limited safety data available. Recommended for professional use only.
Sustainability
As a synthetic material, production involves petrochemical feedstocks. No known ecological concerns at current usage levels, but energy-intensive manufacturing process.
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References
- Bauer et al. (2001). Common Fragrance and Flavor Materials.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID2052104
Physical Properties
| Molecular Weight | 150.221 g/mol🔬 EPA CompTox |
| Density | 0.979 g/cm^3📊 OPERA |
| Boiling Point | 228.5 °C🔬 EPA CTX |
| Melting Point | 36.5 °C🔬 EPA CTX |
| Flash Point | 97.041 °C📊 OPERA |
| Refractive Index | 1.523 Dimensionless📊 OPERA |
| Molar Volume | 154.211 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.207 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.207 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.206 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.59 Log10 unitless📊 OPERA |
| Water Solubility | 0.011 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.023 mmHg📊 OPERA |
| Viscosity | 8.422 cP📊 OPERA |
| Surface Tension | 34.504 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.89 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 | 1 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 47.144 cm^3/mol📊 OPERA |
| Polarizability | 18.689 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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