In the specialty chemical industry, choosing between Methyl 12-Hydroxy Stearate (M12HSA) and Methyl Ricinoleate (MR) is a choice between saturation and unsaturation. While both are methyl esters derived from castor oil, their physical states and chemical reactivities are polar opposites.
Below is the professional, A-to-Z comparison formatted specifically for your Buyer
For formulators working with lubricants, cosmetics, and plastic additives, understanding the functional difference between Methyl 12-Hydroxy Stearate and Methyl Ricinoleate is critical. Although both molecules share a similar chemical backbone, the presence (or absence) of a double bond completely changes their industrial application.
This article provides a deep-dive comparison into the specifications, performance, and best-use cases for these two high-value castor derivatives.
Executive Summary
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Methyl 12-Hydroxy Stearate (M12HSA): A saturated ester produced by the esterification of 12-HSA. It is a solid, waxy material at room temperature, known for its high melting point and stability.
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Methyl Ricinoleate (MR): An unsaturated ester produced by the transesterification of castor oil. it is a clear, oily liquid at room temperature, prized for its fluid lubricity and chemical reactivity.
Technical Specification Comparison Table
| Parameter | Methyl 12-Hydroxy Stearate (M12HSA) | Methyl Ricinoleate (MR) |
| Appearance | White to Creamish Waxy Solid | Clear, Pale Yellow Liquid |
| Chemical Nature | Saturated (No double bonds) | Unsaturated (Contains double bonds) |
| Melting Point | 48°C – 53°C | Below -10°C (Liquid at RT) |
| Iodine Value | Max 4.0 (Low reactivity) | 82 – 90 (Highly reactive) |
| Acid Value | Max 5.0 mg KOH/g | Max 2.0 mg KOH/g |
| Hydroxyl Value | 155 – 165 | 150 – 160 |
| Saponification Value | 175 – 185 | 175 – 185 |
| Color (Gardner) | Max 2 – 4 | Max 2 – 4 |
Key Differentiators: From A to Z
1. Physical State and Handling
The most striking difference is the physical form. M12HSA is a hard wax that must be melted before use in liquid formulations. Methyl Ricinoleate is a fluid oil, making it much easier to blend at room temperature in lubricants, fuels, and liquid cosmetics.2
2. Oxidative Stability
Because M12HSA is saturated (it has no double bonds), it is extremely resistant to oxidation and rancidity. It can withstand high temperatures without darkening or breaking down. Methyl Ricinoleate, being unsaturated, is more prone to oxidation but offers better low-temperature performance because it does not solidify easily.
3. Solvent and Plasticizing Power
Methyl Ricinoleate is an exceptional bio-based solvent and plasticizer.3 Its liquid nature allows it to penetrate and soften polymers effectively. M12HSA, while used as a lubricant in plastics, acts more as an internal processing aid that provides a smooth finish to the final molded part.
4. Chemical Reactivity
The double bond in Methyl Ricinoleate makes it a versatile intermediate for further chemical reactions, such as epoxidation or sulfonation. M12HSA is chemically “quieter,” making it the preferred choice when you need a stable, non-reactive ingredient that simply provides structural integrity or lubrication.
Industry Applications
Where to use Methyl 12-Hydroxy Stearate (M12HSA):
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Lubricating Greases: Used as a component in high-performance grease thickeners.
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Cosmetics: Acts as an opacifier and structural agent in lipsticks, deodorants, and stick-form products.
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Plastic Processing: Excellent internal lubricant for PVC and other engineering plastics.
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Polishes: Used in automotive and furniture waxes for a hard, durable shine.
Where to use Methyl Ricinoleate (MR):
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Bio-Fuels & Fuel Additives: Used to improve the lubricity of low-sulfur diesel fuels.
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Plasticizers: A primary bio-plasticizer for nitrocellulose and rubber compounds.
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Cutting Oils: Acts as a high-performance additive in metalworking fluids.
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Surfactants: A starting material for specialized wetting agents and detergents.
Pros and Cons
Methyl 12-Hydroxy Stearate (M12HSA)
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Pros: Excellent thermal stability, high melting point, non-reactive, long shelf life.
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Cons: Requires heating to incorporate into liquid systems; not suitable as a low-temp plasticizer.
Methyl Ricinoleate (MR)
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Pros: Liquid at room temperature, superior low-temperature properties, excellent solvent power.
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Cons: Lower oxidative stability than M12HSA; can darken over time if not stored correctly.
The Verdict: Which one should you choose?
If your application requires a solid wax that provides heat stability and structural rigidity (like in a lipstick or a hard plastic lubricant), Methyl 12-Hydroxy Stearate (M12HSA) is the standard choice.
If you need a liquid additive that provides lubricity, plasticization, or acts as a chemical intermediate (like in fuel additives or metalworking fluids), Methyl Ricinoleate (MR) is the superior option.
