Castor Oil Chemical Overview
Castor oil is a natural oil obtained from the seeds of the Ricinus communis plant (castor bean plant). It is also known as ricinus oil, palma christi oil, or castor seed oil and has pharmaceuticals, cosmetics, agriculture, and manufacturing uses. Thanks to its viscosity, excellent lubricity, and unique chemical composition, it serves as a useful and indispensable product in many industries.
Cold-pressed and refined castor oil has been employed for thousands of years because of its anti-inflammatory, emollient and lubricating effects. Nowadays, castor oil plays an important role in laxatives, skin creams, hair conditioners, lubricants, coatings and most unusual biodiesel.
Because of its versatility, and plant-based origins, castor oil has a growing global demand and is expected to exceed a $1.8 billion market value by 2028. This article describes the properties, uses, and sourcing considerations associated with castor oil so you can assess which grade of castor oil to incorporate into your process and products.
An Overview of the Properties of Castor Oil
Castor oil has a distinct chemical profile that differentiates it from other vegetable oils. Its high concentration of ricinoleic acid gives it unique physical and chemical properties that influence how it performs in personal care products, pharmaceuticals, and industrial formulations. By knowing these key properties, formulators and buyers can evaluate its performance, compatibility, and stability in different applications.
Key Facts About Castor Oil:
- Compound Name: Castor Oil
- Synonyms: Ricinus oil, Oil of Palma Christi, Castor seed oil
- Chemical Nature: Mixture of triglycerides, primarily containing ricinoleic acid (a monounsaturated omega-9 fatty acid
- Main compound: Ricinoleic acid
- Chemical formula (ricinoleic acid): C₁₈H₃₄O₃
- CAS Numbers:
- Castor oil (whole): 8001-79-4
- Ricinoleic acid: 141-22-0
- Molar Mass:
- Castor oil: Not applicable (mixture)
- Ricinoleic acid: 298.49 g/mol
- Appearance: Pale yellow to nearly colorless viscous liquid with a smooth texture and mild characteristic odor
Density
Castor oil’s density ranges between 0.960 and 0.970 g/cm³ at 20 °C. This is a higher density than most vegetable oils and therefore contributes to its performance in lubricating and thickening applications.
Boiling and Melting Points
The boiling point of castor oil is around 313 °C (595 °F), making it suitable for use in high-temperature industrial and mechanical processes. Its melting point ranges from -10 °C to -18 °C (14 °F to 0 °F), which allows it to remain liquid in typical storage and handling environments.
Castor Oil is a vital ingredient in skin treatments and skincare products. Skincare and dermatology labs in the United States looking for Castor Oil, call Lab Alley at 512-668-9918 to order the ideal size and grade for your application.
Solubility Profile
Castor oil is insoluble in water. Its long hydrocarbon chains and hydrophobic nature prevent it from mixing with aqueous systems, making it an excellent choice for water-repellent formulations.
Castor oil is also soluble in alcohol, chloroform, ether, acetic acid, and other organic solvents. This profile enables its use in a wide range of organic formulations and chemical processes, including cosmetic and pharmaceutical products.
pH Level
Because castor oil is non-aqueous, it does not have a measurable pH value. It is considered neutral and skin-compatible when formulated correctly, which contributes to its popularity in personal care products.
Reactivity
The hydroxyl groups present in ricinoleic acid make castor oil chemically reactive and versatile. It is commonly used in esterification processes for plasticizers and lubricants, transesterification for biodiesel production, and polymerization for creating polyurethanes and resins.
While it blends well with many oils and additives, Castor oil should be stored away from strong oxidizing agents to prevent degradation or unsafe reactions.
Castor Oil sold by Lab Alley comes in multiple grades and sizes, ranging from 500mL to 55-gallon drums.
Uses & Benefits
Thanks to its rich composition and multifunctional properties, castor oil is an important ingredient across industries, ranging from large-scale manufacturing to personal care products. It is a valuable choice for formulators looking for performance, stability, and plant-based solutions.
Industrial Applications
In manufacturing, castor oil serves as a raw material for lubricants, greases, and coatings. It delivers performance in high-temperature and high-stress environments. In paints and varnishes, castor oil acts as a plasticizer and stabilizer, improving flexibility and durability.
The polymer industry uses castor oil to produce polyurethanes, nylon 11, and bio-based plastics. Adhesives and sealants include castor oil for better adhesion, elasticity, and chemical resistance.
Scientific & Laboratory Uses
In laboratories, castor oil works as a reagent and carrier medium for organic synthesis and chemical processing. It provides stability in pH-controlled formulations and helps adjust viscosity in experimental products. Castor oil also serves as an embedding medium for microscopy and supports research on drug delivery, bio-lubrication, and biopolymer performance.
Consumer & Household Uses
In the consumer market, castor oil has a long history of use in skin and hair care products. You can find it in moisturizers, shampoos, soaps, and hair oils, where it helps retain hydration and adds shine. For home care, pharmaceutical-grade castor oil is traditionally used as a laxative under medical supervision. It is also applied topically as a massage oil or to help soothe sore muscles.
Specialized Applications
Castor oil has important roles in several specialized fields. In pharmaceuticals for instance, castor oil acts as an excipient in oral and topical medications and as a vehicle for injectable drugs.
In cosmetics, it is common in lipsticks, conditioners, and cleansing products. On the other hand, agriculture relies on castor oil as a natural pesticide and fungicide and in some soil treatments. And in food processing, food-grade castor oil serves as a mold inhibitor and release agent for baking.
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Safety Information
Castor oil has a low hazard profile compared to many other industrial chemicals. It is non-flammable, non-corrosive, and generally well-tolerated when used correctly.
Keep in mind that prolonged or repeated skin contact can cause mild irritation in sensitive individuals and ingesting large amounts has a laxative effect. Avoid inhaling mists or aerosolized forms of the oil.
Personal Protective Equipment (PPE)
It’s important to use basic protective equipment when handling castor oil in industrial or laboratory settings: wear nitrile or chemical-resistant gloves to protect your skin and use safety goggles or a face shield when handling large volumes or if splashing is possible.
A lab coat or protective apron can provide additional protection during handling. Make sure to work in well-ventilated areas, especially when heating the oil or working with sprays and mists.
Storage Guidelines
Castor oil should be stored at room temperature between 15°C and 25°C (59°F to 77°F). Keep it in tightly sealed, inert containers such as HDPE or glass bottles. Protect it from heat and direct sunlight to prevent degradation.
While castor oil is stable under normal conditions, exposure to air over time can lead to oxidation. Keep it away from strong oxidizing agents to prevent unwanted chemical reactions.
Spill & Disposal Procedures
In the event of a spill, absorb the oil using inert materials like sand, earth, or commercial absorbents. Clean the affected area thoroughly with detergent and water. Prevent large quantities from entering drains or natural water sources.
Dispose of small amounts as non-hazardous waste according to local regulations. For larger volumes, use a licensed waste disposal contractor and follow regional and federal guidelines.
For more detailed information, including first aid instructions, ecological data, and regulatory compliance, consult the Safety Data Sheet (SDS) for castor oil.
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FAQs
What is castor oil and where does it come from?
Castor oil is a vegetable oil extracted from the seeds of the Ricinus communis plant. It’s rich in ricinoleic acid, a unique fatty acid known for its moisturizing, anti-inflammatory, and mild laxative properties.
Are there any side effects of using castor oil?
How should castor oil be stored?
Does castor oil expire?
Yes, castor oil can expire. The typical shelf life of castor oil is 12 to 24 months, depending on purity, formulation, packaging, and storage conditions. High-quality, properly packaged castor oil can remain stable for up to two years if unopened and stored correctly.
