4-Isopropyl-1-methylcyclohexene (CAS 29350-67-2) — Woody Top to Middle Note Fragrance Ingredient
4-Isopropyl-1-methylcyclohexene
CAS 29350-67-2
What Is 4-Isopropyl-1-methylcyclohexene?
4-Isopropyl-1-methylcyclohexene is a synthetic ingredient used in modern fragrances to create crisp, woody aromas. You’ll encounter it in masculine colognes and fresh household products. This molecule matters because it helps perfumers replicate natural forest scents sustainably without harvesting endangered plants, while offering superior stability in formulations.
Safety Profile
GENERALLY SAFEWhat Does 4-Isopropyl-1-methylcyclohexene Smell Like?
Opens with a burst of crushed pine needles and freshly planed cedarwood, like walking through a lumberyard after rain. The heart develops into polished oak paneling with a subtle gasoline edge reminiscent of high-performance engines. Dry-down reveals a clean, almost metallic woodiness that lingers close to skin.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Provides the flinty mineral accord that complements the vetiver, creating an impression of sun-baked pebbles.
Used in trace amounts to sharpen the ambroxan base with a pencil-shaving crispness.
Chemistry, Properties & Perfumer Guide
The Chemistry
A monoterpene hydrocarbon with a bridged cyclohexene structure. Synthesized via acid-catalyzed isomerization of α-pinene or β-pinene precursors. The isopropyl group creates steric hindrance that slows oxidative degradation compared to simpler terpenes. No chiral centers present in this configuration.
Physical & Chemical Properties
| Appearance | Clear colorless liquid |
|---|---|
| Boiling Point | 175-180°C |
| Density | 0.86 g/cm³ |
| Refractive Index | 1.462 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | 0.5-5% | Adds structural definition to woody accords |
| Functional Fragrances | 0.2-1% | Up to 2% | Clean masculine character for detergents |
Classic Accords
Tip: Stabilize with 0.1% BHT to prevent polymerization in bases containing citrus oils.
Alternatives & Comparisons
When a cooler, more camphoraceous wood note is needed without the gasoline nuance.
For brighter citrus-woody effects where less structural rigidity is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards.
RIFM Assessment
RIFM evaluation pending – considered low priority due to limited exposure scenarios.
Sustainability
Synthesized from renewable turpentine feedstocks. Production requires minimal water compared to natural wood oil extraction. Biodegradation studies show 80% breakdown in 28 days under OECD 301B conditions.
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References
- PubChem Compound Summary for CID 15600 PubChem
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
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