4-Isopropylphenol (CAS 99-89-8) — Woody Middle Note Fragrance Ingredient
4-Isopropylphenol
CAS 99-89-8
What Is 4-Isopropylphenol?
4-Isopropylphenol is a synthetic aromatic compound used in industrial fragrances and disinfectants. Consumers may encounter it in household cleaners or as a minor component in some masculine colognes. This phenol derivative matters because it contributes medicinal, smoky facets to fragrances while requiring careful handling due to its potential skin sensitivity.
Safety Profile
USE WITH AWARENESSWhat Does 4-Isopropylphenol Smell Like?
4-Isopropylphenol presents a sharp, medicinal phenolic character reminiscent of disinfectants or tar, with a secondary smoky leather nuance. The initial punch evolves into a dry, woody-herbal persistence that lingers stubbornly. While harsh at full strength, when diluted it can add intriguing antiseptic facets to masculine fougères or leather accords.
Chemistry, Properties & Perfumer Guide
The Chemistry
This simple alkylphenol consists of a phenol ring substituted with an isopropyl group at the 4-position. Synthesized via Friedel-Crafts alkylation of phenol with isopropyl alcohol or propylene. Lacks chirality due to its symmetrical structure. The electron-donating isopropyl group increases the phenol’s reactivity compared to unsubstituted phenol.
Physical & Chemical Properties
| Boiling Point | 232-234 °C |
|---|---|
| Melting Point | 61-63 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Max 1% | Used sparingly for phenolic effects |
| Functional Fragrances | 0.05-0.2% | Max 0.5% | Disinfectant character |
Classic Accords
Tip: Always test at 10% dilution first – phenolic character can overwhelm blends.
Alternatives & Comparisons
Less aggressive phenolic alternative with similar medicinal character but lower irritation potential.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not specifically restricted under IFRA, but falls under general phenol limitations (Amendment 49).
GHS Classification
RIFM Assessment
No specific RIFM evaluation found – treat as potential sensitizer based on phenol structure.
Sustainability
Produced petrochemically with moderate environmental impact. No natural sources known. Waste streams require phenol-specific treatment due to toxicity. Not considered renewable.
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References
- PubChem Compound Summary for 4-Isopropylphenol PubChem CID 7274
- IFRA Standards Library Amendment 49 IFRA Amendment 49
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
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