Sodium citrate (CAS 68-04-2) — Citrus N/A Note Fragrance Ingredient
Sodium citrate
CAS 68-04-2
What Is Sodium citrate?
Sodium citrate is a synthetic salt commonly used as a pH regulator and preservative in foods, cosmetics, and pharmaceuticals. It’s found in everything from soft drinks to skincare products. While odorless itself, it plays a crucial role in stabilizing fragrances by maintaining optimal acidity levels, preventing degradation of delicate scent compounds.
Safety Profile
GENERALLY SAFEWhat Does Sodium citrate Smell Like?
Sodium citrate is completely odorless. As a buffering agent, its primary function in perfumery is chemical stabilization rather than olfactive contribution. It works behind the scenes to maintain fragrance integrity by preventing pH drift that could alter scent profiles or accelerate decomposition of active ingredients.
2D Molecular Structure
SMILES: [Na+].[Na+].[Na+].OC(CC([O-])=O)(CC([O-])=O)C([O-])=O
Chemistry, Properties & Perfumer Guide
The Chemistry
Trisodium citrate is the sodium salt of citric acid with the chemical formula Na₃C₆H₅O₇. Industrially produced through neutralization of citric acid with sodium hydroxide, it exists as white crystalline powder or granules. The compound acts as an excellent chelating agent and buffer, maintaining solutions at pH ~7.6. Its three carboxylate groups give strong water solubility and metal-binding capacity.
Physical & Chemical Properties
| Melting Point | >300 °C (decomposes) |
|---|---|
| Solubility | 72 g/100 mL (water, 25°C) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fragrance Stabilization | 0.1-0.5% | Up to 2% | pH buffer in alcohol-based perfumes |
| Cosmetic Formulations | 0.5-3% | Up to 5% | Preservative booster and chelator |
Classic Accords
Tip: Use as a 10% aqueous solution for precise pH adjustment in fragrance bases.
Alternatives & Comparisons
For more aggressive pH lowering when higher acidity is required in specific formulations.
When combined antimicrobial preservation is needed alongside pH stabilization.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions – commonly used as processing aid rather than fragrance ingredient.
RIFM Assessment
Not evaluated by RIFM as it is not a direct fragrance material.
Sustainability
Produced from citric acid derived via fermentation of carbohydrates, typically from corn or beet molasses. The synthetic process is energy-efficient with high yield. Biodegradable and non-bioaccumulative, though large-scale production relies on agricultural feedstocks.
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References
- PubChem Compound Summary for CID 6224, Sodium citrate PubChem
- FDA Code of Federal Regulations Title 21, Sec. 184.1751 FDA GRAS
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPerfumers Notes
Regulatory Status
FEMA GRAS #3026
Standard Dilution
10% in DPG (standard dilution for most fragrance materials)
Typical Usage Levels
FEMA GRAS (#3026) — typical use 0.01-5% in fragrance.
Ingredient Data Sheet
CAS 68-04-2Physical Properties
| Molecular Weight | 258.07 g/mol🔬 PubChem |
| Vapor Pressure | 0 mmHg @ 25°C📊 OPERA |
| SMILES | C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])O.[Na+].[Na+].[Na+]🔬 PubChem |
Odor & Flavor
| Functional Groups | alcohol💻 RDKit |
| Sodium citrate is odorless and has a pleasant, acid taste. Sodium citrate is anhydrous or contains two molecules of water of crystallization.📖 Fenaroli | |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID2026363
Physical Properties
| Molecular Weight | 258.07 g/mol🔬 PubChem |
| Density | 1.857 g/cm^3🔬 EPA CTX |
| Boiling Point | 318 °C📊 OPERA |
| Melting Point | 175 °C📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | -2.25 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | -6.02 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | -7.92 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.91 Log10 unitless📊 OPERA |
| Water Solubility | 1.136 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0 mmHg📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 140.62 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 7 count💻 Computed |
| Rotatable Bonds | 5 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 29.2 cm^3/mol💻 Computed |
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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