1. Technical Overview
Sodium Ricinoleate ($C_{18}H_{33}NaO_3$) is the sodium salt of Ricinoleic acid, derived from high-purity castor oil through a controlled saponification process. It is a powerful, bio-based anionic surfactant known for its unique combination of emulsifying, dispersing, and bactericidal properties. Unlike standard sodium soaps (like sodium stearate), Sodium Ricinoleate contains a secondary hydroxyl group and a double bond, which significantly increases its solubility in water and its ability to act as a specialized wetting agent. In industrial R&D, it is valued for its performance in transparent soaps, textile lubricants, and as a stabilizer in pharmaceutical and dental formulations.
2. Chemical Structure & Composition
The molecular structure of Sodium Ricinoleate is defined by the substitution of the hydrogen in the carboxyl group with a sodium ion.
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Hydrophilic Head: The ionic carboxylate group ($–COONa$) provides high water solubility.
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Hydrophobic Tail: An 18-carbon chain featuring a hydroxyl group at C12 and a cis-double bond at C9.
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Trifunctionality: Retains the chemical reactivity of the parent ricinoleic chain, allowing for further modifications.
The unique geometry caused by the hydroxyl group prevents the molecules from packing tightly, which is why Sodium Ricinoleate soaps remain much more soluble and lower in viscosity than other long-chain fatty acid soaps.
3. Physical & Chemical Properties
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Appearance: Pale yellow to amber viscous liquid or paste (depending on concentration).
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Solubility: Highly soluble in water, forming clear or slightly opalescent solutions. Also soluble in alcohol.
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pH: Typically alkaline (pH 9.5 – 11.5) in aqueous solution.
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Odor: Faint, characteristic fatty odor.
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Active Matter: Usually supplied in 30% to 50% aqueous solutions or as a concentrated paste.
4. Reaction Chemistry
Sodium Ricinoleate functions as a multi-purpose chemical agent:
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Emulsification: It drastically reduces the interfacial tension between oil and water, creating stable micro-emulsions.
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Micelle Formation: At the Critical Micelle Concentration (CMC), it forms spherical aggregates that can encapsulate hydrophobic active ingredients.
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Bactericidal Action: Due to the hydroxyl group, it exhibits mild antiseptic properties, particularly effective in inhibiting the growth of certain oral and skin bacteria.
5. When to Use vs. When NOT to Use
Use Sodium Ricinoleate when:
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Manufacturing transparent “glycerin” soaps where high clarity and solubility are required.
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Formulating specialized toothpastes or mouthwashes to help dissolve dental plaque and provide mild antiseptic benefits.
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Seeking a bio-based wetting agent for textile processing or leather fat-liquoring.
Do NOT use Sodium Ricinoleate when:
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The formulation is highly acidic (pH < 7), as the soap will revert to free Ricinoleic acid and precipitate out of the solution.
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The application requires a high-foaming detergent (it provides a stable, creamy lather rather than high-volume bubbles).
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Use in “hard water” without chelating agents, as it will form insoluble calcium/magnesium curds (soap scum).
6. Compatibility Profile
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With Anionic Surfactants: Highly compatible with SLES and other fatty acid soaps.
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With Non-ionic Surfactants: Synergistic with ethoxylated castor oils for stable emulsion systems.
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With Electrolytes: Sensitivity to high salt concentrations can cause “salting out” of the soap.
7. Manufacturing Process (Product Focus)
Nova Industries produces Sodium Ricinoleate via a precision saponification method:
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Hydrolysis/Saponification: High-purity Ricinoleic acid or Refined Castor Oil is reacted with a standardized Sodium Hydroxide ($NaOH$) solution.
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Temperature Control: The reaction is kept within a specific thermal range to ensure complete conversion without darkening the product.
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Refining: The resulting soap is filtered to remove any trace particulates or unsaponifiable matter.
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Standardization: The active matter and pH are adjusted to meet the specific requirements of the end-user (liquid or paste form).
8. Technical Specifications Table
| Parameter |
Specification (Aqueous Solution Grade) |
| Appearance |
Pale Yellow to Amber Viscous Liquid |
| Active Matter |
35% – 40% (Customizable) |
| Free Alkali (as $NaOH$) |
0.5% Max |
| pH (1% Solution) |
9.5 – 11.0 |
| Total Fatty Matter |
30% Min |
| Color (Gardner) |
4.0 Max |
9. Quality Grade Analysis
Nova Industries monitors the Free Alkali and Total Fatty Matter (TFM). Excessive free alkali can be irritating in personal care products, while low TFM indicates a diluted product. Our process ensures a high-TFM soap with minimal free alkali, providing a safe and efficient surfactant for sensitive applications.
10. Impact of Impurities
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Residual Glycerin: If made directly from castor oil, glycerin remains in the product, which is beneficial for moisturizing but may affect the drying speed in industrial coatings.
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Unreacted Oil: Can cause haziness in transparent soaps and reduce the cleaning efficiency.
11. Industry-Wise Application 1: Personal Care & Hygiene
Widely used in the manufacture of high-quality shaving creams, transparent bar soaps, and medicated shampoos. It provides a smooth, lubricious feel and helps in the stable suspension of fragrances.
12. Industry-Wise Application 2: Oral Care
In the dental industry, Sodium Ricinoleate is used in specialized oral hygiene products. It is effective at detoxifying bacterial byproducts and is often used in formulations targeting gingivitis and periodontal health.
13. Industry-Wise Application 3: Textile & Leather Auxiliaries
Acts as a powerful wetting and leveling agent in the dyeing of cotton and silk. In leather processing, it is used for emulsifying fats to ensure deep and uniform penetration into the hides (fat-liquoring).
14. Industry-Wise Application 4: Industrial Emulsifiers
Used in the production of cutting oils, soluble oils, and pesticide emulsifiable concentrates (EC). It helps maintain the stability of the oil-in-water emulsion under varying temperature conditions.
15. Formulation Guide
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Clear Soaps: Use at 5% to 15% of the total fatty matter to improve transparency and solubility.
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Liquid Sprays: For odor control or antiseptic use, a 1% to 2% active concentration is typically sufficient.
16. Sustainability Data
Sodium Ricinoleate is 100% bio-based (excluding the sodium component). It is readily biodegradable, non-toxic to aquatic life at standard dilutions, and provides an eco-friendly alternative to synthetic alkyl sulfates.
17. Packaging & Logistics (Technical)
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Standard: 50kg or 200kg HDPE Drums.
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Bulk: 1000kg IBC Tanks.
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Logistics: Non-hazardous for transport. Protect from extreme cold, as the product may thicken or partially solidify (reversible upon warming).
18. Storage Science
Should be stored in a cool, dry area. Because it is an alkaline soap, it should be kept in plastic or epoxy-lined containers to prevent corrosion of metallic drums. Keep containers tightly sealed to prevent the absorption of atmospheric $CO_2$, which could lower the pH and destabilize the soap.
19. Troubleshooting Guide
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Problem: Product has turned cloudy. Solution: Check the pH; if it has dropped below 9.0, add a small amount of dilute $NaOH$ to restore clarity.
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Problem: Thickening or gelling in the drum. Solution: This is natural for high-concentration soaps in cold weather; gently warm the drum to 30-40°C.
20. Regulatory Compliance
Our Sodium Ricinoleate is REACH Compliant and manufactured under strict quality control. It is listed on major global chemical inventories (TSCA, DSL, AICS).
21. Safety (SDS Summary)
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Handling: Wear protective gloves and eyewear; the alkaline nature can cause skin and eye irritation.
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First Aid: Flush with water for 15 minutes if contact occurs.
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Environment: Biodegradable; do not discharge concentrated soap into small water bodies.
22. Sample Validation Process
Test for Active Matter and pH. For personal care applications, a “Foam Stability Test” and a “Clarity Test” in your specific formulation are recommended.
23. Commercial Efficiency
By sourcing standardized Sodium Ricinoleate from Nova Industries, manufacturers can bypass the complex saponification step in their own plants. This ensures a consistent, high-purity surfactant that simplifies the production of high-end soaps and emulsions.
24. Technical FAQs
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Is Sodium Ricinoleate the same as Castor Soap? Yes, it is the primary component of soap made exclusively from castor oil.
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Can it be used in organic products? Yes, it is derived from natural vegetable oil and is a traditional soap-making ingredient.
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Is it safe for oral use? Yes, it has a long history of use in toothpaste and mouthwashes at low concentrations.
25. Contact CTA
For Technical Data Sheets (TDS), customized active matter concentrations, or to request a sample, please contact our export department: export@novaind.in
