Sodium hydroxide (CAS 1310-73-2) — Citrus N/A Note Fragrance Ingredient

ByThe Good Scents
Citrus · Floral

Sodium hydroxide

CAS 1310-73-2

Origin
synthetic
Note
N/A
IFRA
Professional use
Data as of: Apr 2026

What Is Sodium hydroxide?

Sodium hydroxide, commonly known as lye, is a highly alkaline chemical used in soap making, drain cleaners, and industrial processes. It’s not typically found in finished fragrances but may be used in saponification during soap production. This inorganic compound is crucial for pH adjustment in cosmetic formulations and plays a behind-the-scenes role in creating some fragrance delivery systems.

Safety Profile

PROFESSIONAL USE
Generally safeUse with awarenessProfessional use
⚠ Severe skin and eye irritant
✗ Requires protective equipment
CAS
1310-73-2
Formula
Mixture
MW
Variable
Odor Family
Citrus · Floral
Layer 1 · Enthusiast

What Does Sodium hydroxide Smell Like?

Layer 2

Chemistry, Properties & Perfumer Guide

The Chemistry

Sodium hydroxide (NaOH) is an inorganic ionic compound consisting of sodium cations and hydroxide anions. It is produced industrially through the chloralkali process by electrolysis of sodium chloride solutions. The compound forms a strongly alkaline solution in water, dissociating completely into ions. In perfumery, its primary use is in saponification reactions to convert fatty acids into soap bases that can carry fragrance.

Physical & Chemical Properties

Melting Point318 °C
Solubility111 g/100 mL (20°C)

Perfumer Guide

Note Position
N/A
Volatility
N/A
Blending
N/A
ApplicationTypical %RangeNotes
Soap MakingVariableAs neededFor saponification calculations
pH AdjustmentTrace<0.1%Formula stabilization

Classic Accords

Tip: Always add sodium hydroxide to water (never water to NaOH) to prevent dangerous exothermic reactions.

Alternatives & Comparisons

1
Potassium hydroxide CAS 1310-58-3

Used similarly for liquid soap production, creates softer soaps than NaOH.

2
Triethanolamine CAS 102-71-6

Milder alkaline agent for pH adjustment in cosmetic formulations.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

Not regulated by IFRA as it’s not a fragrance material

GHS Classification

H290 May be corrosive to metals H314 Causes severe skin burns and eye damage

RIFM Assessment

Not evaluated by RIFM as it’s not a fragrance ingredient

Sustainability

Industrial production of sodium hydroxide is energy intensive but essential for many chemical processes. Modern chloralkali plants have implemented mercury-free membrane cell technology to reduce environmental impact. While not renewable, it is widely recycled in industrial applications. Proper handling prevents environmental release of this highly alkaline material.

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References

    Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

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