Span 40
Non-ionic Emulsifier with Low HLB Value
Span 40 (Sorbitan Monopalmitate) is a non-ionic emulsifier and stabilizer primarily used in water-in-oil (W/O) emulsions.
It is produced by the esterification of sorbitol with palmitic acid and is widely used across food, cosmetic, pharmaceutical, and chemical industries due to its excellent compatibility with oils and fats, thermal stability, and natural origin.
Chemical Composition and Structure
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Chemical Name: Sorbitan Monopalmitate
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Molecular Formula: C₂₂H₄₂O₆
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Molecular Weight: 402.56 g/mol
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CAS Number: 26266-57-9
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Chemical Type: Non-ionic fatty acid ester
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HLB Value: ~6.7 (ideal for W/O emulsions)
Molecular Structure:
Span 40 consists of a hydrophilic sorbitol backbone esterified with a lipophilic palmitic acid chain, providing balanced emulsifying and stabilizing properties.
Physical and Chemical Properties
| Property | Typical Value |
|---|---|
| Appearance | Yellowish to light brown wax or powder |
| Odor | Mild, nearly odorless |
| Density (20°C) | ≈ 1.03 g/cm³ |
| Melting Point | 42–47°C |
| Solubility | Soluble in oils and organic solvents; insoluble in water |
| HLB Value | ~6.7 |
| Thermal Stability | Stable under normal food and cosmetic processing conditions |
| Ionic Nature | Non-ionic |
Applications
1. Food Industry
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Acts as an emulsifier and stabilizer in margarine, chocolate, confectionery creams, and dairy products
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Prevents fat and sugar crystallization
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Improves texture, consistency, and product stability
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Approved for food use under FAO/WHO (E495) regulations
2. Cosmetics and Personal Care
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Used in creams, lotions, balms, and skincare products as an emulsifier and stabilizer
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Enhances oil phase dispersion and skin feel
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Reduces stickiness and improves texture
3. Pharmaceutical Applications
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Provides emulsion stability in semi-solid formulations such as creams and ointments
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Enhances bioavailability of lipophilic active ingredients
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Suitable for controlled-release drug delivery systems
4. Chemical and Industrial Uses
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Emulsion stabilizer in lubricants, industrial oils, and protective coatings
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Homogenizing agent for oil-based formulations
Advantages
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Naturally derived and environmentally friendly
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Excellent thermal and chemical stability
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Non-toxic and safe within permitted usage levels
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Highly compatible with vegetable and animal fats
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Improves emulsion stability, shelf life, and product appearance
Limitations
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Insoluble in water — often blended with high-HLB emulsifiers (e.g., Tween 40) for O/W systems
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High concentrations may affect product texture
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Must comply with FAO/WHO and FDA food-grade usage standards
Safety and Handling
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Hazard Classification: Non-hazardous under normal conditions
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Personal Protective Equipment (PPE): Wear protective gloves, dust mask, and safety goggles when handling solid or powdered form
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Storage Conditions:
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Keep in tightly sealed, moisture-resistant containers
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Store at 15–30°C in a cool, dry, well-ventilated area
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Protect from direct sunlight, heat sources, and oxidizing agents
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Shelf Life: Minimum 24 months under recommended conditions
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Typical Packaging: 25 kg bags or 200 kg drums
Summary
Span 40 (Sorbitan Monopalmitate) is a versatile, natural-origin, non-ionic emulsifier ideal for water-in-oil systems.
It offers excellent stability, compatibility with oils, and safe performance across a wide range of food, cosmetic, pharmaceutical, and industrial formulations. Its balance of hydrophilic and lipophilic properties makes it a reliable choice for stable, high-quality emulsions.
