Sulfated Castor Oil
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Sulfated castor oil is the first synthetic surfactant which can be used in hard water.
Previously, alizarin was used to stain turkey red, sulfated castor oil was a necessary mordant, also known as turkey red oil.
Sulfation reaction of castor oil is a complex reaction process. Sulfuric acid can react with hydroxyl groups of castor oil, also can react with C=C double bond; in addition, the process of reaction, also accompanies by the hydrolysis of castor oil. Therefore, the product of sulfated castor oil is a complex mixture, wherein ricinoleic acid sulfate sodium salt is one of the main products.
Usually the reaction process as follows:
(1), 100 parts castor oil is added to the kettle, drip 25 parts concentrated sulfuric acid at 30 - 35°C (no more than 35°C), finish within 4 - 6h, continue to stir 2 - 4h.
(2), At 40 - 50°C, clean with equal amount of warm water, remove excess sulfuric acid, stand, remove water. Continue to clean with 10 parts sodium chloride solution (6%, wt), stand, remove water. The reaction products are soluble in water, but not soluble in dilute acid and sodium chloride solution.
(3), Neutralize by 10 - 15% NaOH solution, and when the reaction liquid transforms from emulsion to clarification, stop adding alkali, the expected product is obtained.
Quality Standards & Test Methods
1. Physical and chemical indexes
Physical and chemical indexes
Actives, %, ≥
50.0 - 60.0
pH (25°C, 1% solution)
7.0 - 9.5
Density, 25°C, g/mL, approx
Test Methods
(1), Actives
GB/T 5173 Surface active agents and detergents-Determination of anionic-active matter by direct two-phase titration procedure
ISO 2271 Surface active agents -- Detergents -- Determination of anionic-active matter by manual or mechanical direct two-phase titration procedure