HYDROXYSTEARIC

Hydroxystearic, more precisely 12-hydroxystearic acid or 12-hydroxyoctadecanoic acid (12-HSA), is a saturated C18 hydroxy fatty acid with CAS No 106-14-9 and the formula C18H36O3, obtained mainly from hydrogenated castor oil and supplied as off-white flakes or powder for use as a grease thickener, oil gelling and structuring agent, emulsifier base and chemical intermediate in lubricants, cosmetics, coatings, inks, adhesives and plastics.
The hydroxy fatty acid is valued because one molecule carries two polar groups, a carboxylic acid at the end of the chain and a hydroxyl group in the middle, which allows it to form strong hydrogen-bonded networks in oils and to give metal soaps with an exceptional thickening power and heat resistance.
The castor-derived structurant works either as the free acid, which self-assembles into fine fibrous crystals that gel hydrocarbons, esters and some silicones, or as a soap such as lithium 12-hydroxystearate, which builds the fiber network that turns base oil into a stable lubricating grease.

CAS No: 106-14-9
EC No: 203-366-1
Molecular formula: C18H36O3
Molecular weight: 300.48 g/mol
INCI name: Hydroxystearic Acid
Appearance: Off-white to light yellow flakes or powder
Melting point: approx. 72–80 °C (technical grades)
Flash point: > 210 °C
Acid value: approx. 175–185 mg KOH/g
Hydroxyl value: approx. 150–165 mg KOH/g
Water solubility: Insoluble

COMMON PRODUCT & CHEMICAL NAMES OF HYDROXYSTEARIC:

Hydroxystearic, Hydroxystearic Acid, 12-Hydroxystearic Acid, 12-Hydroxy Stearic Acid, 12-HSA, HSA, 12-Hydroxyoctadecanoic Acid, DL-12-Hydroxystearic Acid, (±)-12-Hydroxyoctadecanoic Acid, Octadecanoic Acid, 12-hydroxy-, Stearic Acid, 12-hydroxy-, 12-Hydroxy Stearic Acid Flakes, 12-HSA Technical Grade, Hydrofol Acid 200, Loxiol G 21, Ceroxin GL, Barolub FTO, Cerit Fac 3

Hydroxystearic Acid is the INCI name of Hydroxystearic, while 12-hydroxyoctadecanoic acid and "octadecanoic acid, 12-hydroxy-" are the systematic and CAS index names. 12-HSA is the abbreviation used throughout the grease and lubricant industry. The prefixes DL- and (±)- indicate the racemic form, because the hydroxyl-bearing carbon is a stereocenter, commercial material made from castor oil is mainly the (R)-isomer. Hydrofol Acid 200, Loxiol G 21, Ceroxin GL, Barolub FTO and Cerit Fac 3 are trade names used by different producers.
The hydroxylated fatty acid should not be confused with stearic acid (octadecanoic acid, CAS 57-11-4), which has no hydroxyl group, or with ricinoleic acid, the unsaturated hydroxy fatty acid of castor oil. Hydrogenated castor oil (castor wax), lithium 12-hydroxystearate, methyl 12-hydroxystearate, poly(12-hydroxystearic acid) and PEG hydroxystearates are derivatives of Hydroxystearic with their own CAS numbers and properties.

WHAT IS HYDROXYSTEARIC?

The hydroxylated fatty acid is a long-chain fatty acid with 18 carbon atoms, a carboxylic acid group at one end and a secondary hydroxyl group on carbon 12. It is the saturated counterpart of ricinoleic acid, which makes up about 85–90 % of the fatty acids in castor oil.
Industrially, Hydroxystearic is produced in two main steps. First, castor oil is hydrogenated to saturate the double bond of ricinoleic acid, giving hydrogenated castor oil (castor wax), which is mainly the triglyceride of 12-hydroxystearic acid. Second, this wax is hydrolyzed (split) to release the free fatty acids and glycerin. The fatty acid fraction is then washed, dried and flaked.
Because castor oil also contains small amounts of other fatty acids, technical Hydroxystearic is not a pure compound. It typically contains a notable proportion of stearic acid and smaller amounts of other fatty acids. For this reason, commercial grades are specified by acid value, hydroxyl value, iodine value, melting point and color rather than by purity alone. High-purity grades are available for laboratory and special uses.

The hydroxy fatty acid is usually delivered as off-white to pale yellow flakes or as a powder. It is practically insoluble in water but dissolves in hot oils, many organic solvents and molten waxes. On cooling, it forms fine fibrous crystals that trap the surrounding liquid, which is the basis of its gelling ability.
The hydroxyl group raises the melting point of Hydroxystearic compared with stearic acid and gives it more polarity. Technical grades melt at roughly 72–80 °C, while highly purified material melts at around 80 °C.

Most of the world's Hydroxystearic goes into lubricating greases. When it is reacted with lithium hydroxide in base oil, it forms lithium 12-hydroxystearate, the most widely used grease thickener. Greases built on this soap combine good mechanical stability, water resistance and a high dropping point, and they serve as multipurpose greases in vehicles, bearings and industrial machinery. The hydroxy fatty acid is also used in calcium and lithium complex greases.
In cosmetics and personal care, Hydroxystearic is a structuring and gelling agent for oils. It helps build the body of sticks, balms, pencils and anhydrous gels, supports pigment dispersion in color cosmetics and, when neutralized in situ, forms soaps that act as oil-in-water emulsifiers. Its higher melting point compared to stearic acid gives firmer, more heat-resistant structures.
In technical applications, Hydroxystearic serves as a thickener, rheology modifier, lubricant, release agent and dispersing aid in coatings, inks, hot-melt adhesives, polishes, wax blends, rubber and plastics, and as a raw material for esters, amides, metal soaps and polyesters.

FOR FORMULATORS, HYDROXYSTEARIC OFFERS A RENEWABLE, CASTOR-OIL-BASED RAW MATERIAL THAT CAN TRANSFORM LIQUID OILS INTO GELS OR GREASES AT LOW USE LEVELS.
For end users, products formulated with Hydroxystearic can mean greases that stay in place under load and heat, sticks that do not soften in warm weather, and coatings with controlled flow and sag resistance.
The castor-derived structurant can be evaluated in lithium and calcium greases, lithium complex greases, cosmetic sticks and gels, antiperspirants, lipsticks and pencils, hair styling waxes, creams and lotions, soaps, inks, paints, hot-melt adhesives, polishes and specialty ester production.

CAS NO, EC / EINECS NO AND CHEMICAL IDENTIFICATION OF HYDROXYSTEARIC

Product name: Hydroxystearic (12-Hydroxystearic Acid)
Common abbreviation: 12-HSA
Chemical name: 12-Hydroxyoctadecanoic acid
INCI name: Hydroxystearic Acid
CAS No: 106-14-9 (other CAS numbers, such as 36377-33-0, are used in some listings for specific isomeric forms)
EC / EINECS No: 203-366-1
Molecular formula: C18H36O3
Molecular weight: 300.48 g/mol
Chemical class: Hydroxy fatty acid, saturated C18 carboxylic acid with a secondary hydroxyl group
Main functions: Grease thickener (via metal soaps), oil gelling and structuring agent, emulsifier base, dispersing aid, lubricant, intermediate for esters, amides and polyesters

The CAS number 106-14-9 identifies the chemical substance, but commercial Hydroxystearic always contains some stearic acid and other fatty acids. Two products with the same CAS number can differ in hydroxyl value, acid value, color and melting point, which directly affects grease yield and gelling performance.
The castor-derived structurant is listed in the EU CosIng database under its INCI name Hydroxystearic Acid and has been reviewed by the US Cosmetic Ingredient Review panel for use in cosmetics. A USP reference standard is also available for analytical purposes.

CHEMICAL STRUCTURE AND MOLECULAR PROPERTIES OF HYDROXYSTEARIC

The molecule of Hydroxystearic can be written as CH3(CH2)5–CH(OH)–(CH2)10–COOH. It consists of a straight saturated chain with a carboxylic acid group at carbon 1 and a hydroxyl group at carbon 12.
This structure gives Hydroxystearic two separate hydrogen-bonding sites. The carboxylic acid groups pair up in head-to-head dimers, while the mid-chain hydroxyl groups form chains of hydrogen bonds along the length of the crystal. Together they drive the molecules to stack into long, thin, twisted fibers rather than plates. These fibers entangle into a three-dimensional network that can immobilize many times their own weight of oil. For this reason Hydroxystearic is one of the best-known low-molecular-weight organogelators.
Carbon 12 is a chiral center. Hydroxystearic made from natural castor oil is mainly the (R)-enantiomer, which forms particularly efficient fibrous gels. Racemic material produced by other routes tends to give weaker gels.

The carboxylic acid group reacts with bases to form soaps. With lithium hydroxide, Hydroxystearic forms lithium 12-hydroxystearate, with calcium hydroxide, calcium 12-hydroxystearate. In greases, these soaps crystallize into fibers that hold the base oil. The hydroxyl group strengthens the fiber network through additional hydrogen bonding, which explains the higher dropping point and better mechanical stability of 12-hydroxystearate greases compared with plain stearate greases.
The carboxylic acid and hydroxyl groups can also be esterified. Self-condensation gives poly(12-hydroxystearic acid), a polymeric dispersant, reaction with ethylene oxide gives PEG hydroxystearates used as nonionic solubilizers, and esterification with methanol gives methyl 12-hydroxystearate.
Because Hydroxystearic is fully saturated, it has good oxidative stability and a low iodine value.

HOW DOES HYDROXYSTEARIC WORK AT THE MOLECULAR LEVEL?
 
Hydroxystearic, the common short name for 12-hydroxystearic acid, can be understood most clearly by comparing it with ordinary stearic acid. Both are saturated C18 fatty acids, but the hydroxystearic molecule carries one extra hydroxyl group on carbon 12. That single polar group in the middle of an otherwise non-polar chain changes how the molecule packs, how it interacts with oils and water, and what can be built from it chemically.
 
What the extra hydroxyl changes in the solid: In stearic acid, chains pack side by side mainly through weak van der Waals forces, and carboxyl groups pair into dimers at the ends. In hydroxystearic, the mid-chain hydroxyl groups add a second row of hydrogen bonds running along the packed chains. This extra cohesion raises the melting range, makes crystals harder and more brittle, and strongly favours elongated, fibre-like crystal growth instead of flat plates.
 
What it changes in oils: Because of these directional hydrogen bonds, the molecule behaves very differently from stearic acid when it crystallises from a hot oil. Rather than settling out as separate crystals, it builds a fine, interconnected fibrillar network that holds the oil in place. A small proportion can therefore turn liquid oils into firm, thermoreversible gels. This behaviour is used to structure sticks, balms, oil-based gels and greases without relying on large amounts of hard fat or wax.
 
What it changes in water-based systems: When the carboxyl group is neutralised, hydroxystearic forms an anionic soap. The mid-chain hydroxyl makes this soap more polar than ordinary stearate and alters how it packs at oil–water interfaces and in liquid-crystalline phases. Partially neutralised mixtures combine soap molecules at interfaces with crystalline free acid in the oil phase, giving emulsions that are both emulsified and internally structured.
 
What it changes in metal soaps: In lithium and calcium soaps used as grease thickeners, the hydroxyl groups add hydrogen bonding between soap molecules. Fibres become stronger and more stable at higher temperatures than those built from plain stearate soaps, giving greases a higher dropping point and better resistance to mechanical breakdown.
 
A molecule that can react with itself: Unlike stearic acid, hydroxystearic carries both a carboxylic acid group and an alcohol group. It can therefore form esters with other molecules of its own kind. Short self-condensation products, called estolides, are branched oligoesters with good lubricity and low-temperature flow, making them useful as bio-based lubricant components. Longer polymers, poly(hydroxystearic acid), provide bulky hydrocarbon chains that stabilise pigment particles and water droplets in oils by steric repulsion.
 
Building block for emollients and solubilisers: The carboxyl group can be esterified with alcohols to give liquid or soft esters, such as ethylhexyl hydroxystearate, that act as emollients and pigment wetting agents in cosmetics. The hydroxyl group remains free and improves pigment dispersion and skin feel. Alternatively, ethylene oxide can be added to the molecule to form polyethylene glycol hydroxystearates. These non-ionic surfactants combine the hydrophobic hydroxystearic tail with a long water-loving chain and are used to solubilise poorly water-soluble active substances in pharmaceutical and cosmetic formulations.
 
Surface behaviour on metals and polymers: At metal surfaces, the acid head anchors to the oxide layer while the chains form a protective hydrophobic film, and the hydroxyl groups strengthen lateral cohesion within that film. In plastics, metal hydroxystearates reduce friction between polymer melt and processing equipment and between polymer chains, acting as lubricants and release aids.
 
Metabolic fate: In the body, hydroxystearic is handled by fatty acid oxidation pathways, with the hydroxyl-bearing segment processed along the way. Safety assessments of its esters and salts take this metabolic route into account.
 
The effects obtained depend on purity and isomer content, concentration, degree of neutralisation or esterification, solvent polarity, cooling rate and the other ingredients present. Hydroxystearic dosage and process conditions should therefore be confirmed through laboratory trials.

PHYSICAL AND CHEMICAL PROPERTIES OF HYDROXYSTEARIC

GENERAL TECHNICAL SPECIFICATIONS:

PHYSICAL APPEARANCE: OFF-WHITE TO LIGHT YELLOW FLAKES, POWDER OR LUMPS
Odor: Faint fatty odor or nearly odorless
Chemical character: Saturated hydroxy fatty acid, weak organic acid
Molecular formula: C18H36O3
Molecular weight: 300.48 g/mol
CAS No: 106-14-9
EC / EINECS No: 203-366-1
Purity: Technical grades contain mainly 12-HSA with some stearic acid, laboratory grades are offered at higher purity
Acid value: Typically approx. 175–185 mg KOH/g
Saponification value: Typically approx. 180–192 mg KOH/g
Hydroxyl value: Typically min. approx. 150–155 mg KOH/g
Iodine value: Typically max. approx. 3–5 g I2/100 g
Color (Gardner): Typically max. approx. 5–7
Melting point: Approx. 72–80 °C (technical), approx. 80 °C (high purity)
Titer: Approx. 72–74 °C
Boiling point: > 300 °C (decomposes)
Flash point: > 210 °C
Water solubility: Insoluble
Solubility in other media: Soluble in hot oils, esters, alcohols and many organic solvents, gels many oils on cooling
Reactivity: Stable under normal conditions, reacts with bases to form soaps, avoid strong oxidizing agents

The hydroxyl value is the most important parameter for grease makers. A higher hydroxyl value means a higher content of 12-HSA relative to stearic acid and generally gives better thickening efficiency and higher dropping points. Acid value is used to calculate the amount of alkali needed for saponification.
Color and iodine value indicate the degree of hydrogenation and the quality of refining. For cosmetic use, low color and low odor are preferred.
These values are typical data from supplier documentation and do not form a binding specification for a particular delivery. For the current specification of the supplied Hydroxystearic grade, please contact Ataman Kimya.

HOW DOES HYDROXYSTEARIC WORK?

AS A GREASE THICKENER
In grease making, Hydroxystearic is saponified in part of the base oil with lithium hydroxide (or calcium hydroxide). The resulting soap is dissolved at high temperature and then cooled under controlled conditions. During cooling, the soap crystallizes into long fibers that form a sponge-like network. The base oil is held in this network by capillary forces and adsorption, so the grease stays in place yet releases oil to the contact zone during operation. The hydroxyl group of 12-HSA strengthens the fiber network and improves the dropping point and shear stability of the grease.

AS AN OIL GELLING AND STRUCTURING AGENT
When free Hydroxystearic is dissolved in a hot oil and then cooled, it self-assembles into fibrous crystals. At concentrations of only a few percent, these crystals create a gel that does not flow. The strength and clarity of the gel depend on the oil type, the 12-HSA concentration, the cooling rate and the presence of other waxes.

AS AN EMULSIFIER BASE
Neutralized in situ with bases such as triethanolamine, sodium hydroxide or potassium hydroxide, Hydroxystearic forms soaps that act as oil-in-water emulsifiers and also thicken the emulsion.

AS A DISPERSING AID AND RHEOLOGY MODIFIER
In inks, coatings and cosmetics, the polar groups of Hydroxystearic adsorb on pigment surfaces while the hydrocarbon chain extends into the oil phase. This improves pigment wetting and dispersion, and the crystal network can provide anti-settling and anti-sag properties.

THE MAIN FUNCTIONS OF HYDROXYSTEARIC CAN BE SUMMARIZED AS:

THICKENER FOR LITHIUM, CALCIUM AND COMPLEX SOAP GREASES
Gelling and structuring agent for oils, esters and some silicones
Hardening agent for sticks, balms and pencils
Emulsifier base when neutralized
Pigment dispersing aid
Rheology modifier and anti-settling agent
Lubricant and release agent in plastics and rubber
Intermediate for esters, amides, metal soaps and polyesters

HYDROXYSTEARIC IN LUBRICATING GREASES

Lubricating greases are the largest application of Hydroxystearic. A grease consists of base oil (usually 80–95 %), a thickener and performance additives.

Lithium 12-hydroxystearate greases
These are the most common multipurpose greases worldwide. They offer a dropping point typically in the range of about 190–200 °C, good water resistance, good mechanical stability and good response to additives. They are used in wheel bearings, chassis lubrication, electric motors, industrial bearings and general machinery.

LITHIUM COMPLEX GREASES
In complex greases, Hydroxystearic is combined with a complexing agent, usually a short-chain dicarboxylic acid such as azelaic or sebacic acid, or with boric acid. The complex soap raises the dropping point above about 250 °C and improves high-temperature performance.

Calcium 12-hydroxystearate greases
Anhydrous calcium greases based on Hydroxystearic offer very good water resistance and are used in marine, food-processing (with suitable registered formulations) and water-exposed applications.

FACTORS THAT INFLUENCE GREASE QUALITY:

HYDROXYL VALUE AND PURITY OF THE HYDROXYSTEARIC
Exact stoichiometry of the alkali
Water content during saponification
Maximum process temperature and holding time
Cooling rate and shear during cooling
Base oil type and viscosity
Milling and homogenization
Additive package

HYDROXYSTEARIC IN COSMETICS AND PERSONAL CARE

In cosmetic formulations, Hydroxystearic is used at relatively low levels as a structuring agent, co-emulsifier and texture modifier.

TYPICAL COSMETIC USES:

ANTIPERSPIRANT AND DEODORANT STICKS
Lipsticks, lip balms and cosmetic pencils
Sun protection sticks
Hair styling waxes and pomades
Anhydrous gels and oil gels
Creams and lotions as co-emulsifier or consistency factor
Soaps and cleansing products
Color cosmetics as pigment dispersing aid

The hydroxylated fatty acid is generally added to the hot oil phase above its melting point. In anhydrous products, it gels the oils on cooling, in emulsions, it can be neutralized to form an emulsifier or used as a co-structurant with fatty alcohols and waxes.
Cosmetic use requires a grade with suitable color, odor and purity. The final product must be assessed according to the cosmetic legislation of the target market.

IN WHICH SECTORS IS HYDROXYSTEARIC USED?

MAIN AREAS OF USE:

LUBRICATING GREASES (LITHIUM, LITHIUM COMPLEX, CALCIUM)
Cosmetics and personal care
Coatings and paints (rheology and dispersion)
Printing inks
Hot-melt adhesives
Polishes and wax blends
Rubber and plastics processing (lubricant, release agent)
Textile auxiliaries (lubricants)
Specialty chemicals (esters, amides, polyesters, metal soaps)
Pharmaceutical excipient production (as raw material for PEG hydroxystearates)

Grease producers mainly look at hydroxyl value, acid value and consistency of quality from batch to batch. Cosmetic producers focus on color, odor and purity. Coating and ink producers look at dispersion performance and compatibility with their binder system.

IS HYDROXYSTEARIC USED IN COSMETIC, FOOD, AND PHARMACEUTICAL APPLICATIONS?

Cosmetics: Yes. The hydroxy fatty acid is listed in CosIng with the INCI name Hydroxystearic Acid and is used in sticks, balms, creams, lotions and soaps. It has been reviewed by the CIR panel for cosmetic use. Suitable cosmetic grades should be used.
Food: Hydroxystearic is not a food additive and has no E number. Certain derivatives, such as hydroxystearic acid–polyethylene glycol block polymers, are permitted under US FDA indirect food additive regulations for specific uses in paper and paperboard manufacturing. Greases based on Hydroxystearic can be used for incidental food contact only when formulated and registered for this purpose.
Pharmaceuticals: Free Hydroxystearic is not a common excipient, but it is the raw material for macrogol (PEG) 15 hydroxystearate, a pharmacopoeial nonionic solubilizer used in injectable and oral formulations. A USP reference standard for Hydroxystearic exists for analytical purposes.
Technical grades intended for greases and industrial applications should not be used in cosmetic, food or pharmaceutical products.

INDUSTRIAL APPLICATIONS OF HYDROXYSTEARIC

COATINGS AND PAINTS
Purpose: To control rheology, prevent sagging and help disperse pigments.
Role of Hydroxystearic: Forms a fiber network in solvent-borne systems and acts as a dispersing aid.
Limitations: Activation temperature and solvent compatibility must be controlled, overheating can destroy the network.

PRINTING INKS
Purpose: To improve pigment wetting and flow.
Role of Hydroxystearic: Dispersing aid and rheology modifier.

HOT-MELT ADHESIVES AND WAX BLENDS
Purpose: To adjust melting behavior, hardness and setting time.
Role of Hydroxystearic: Structuring and crystallization-controlling component.

RUBBER AND PLASTICS
Purpose: To improve processing and mold release.
Role of Hydroxystearic: Internal and external lubricant, raw material for metal soaps used as stabilizers and lubricants.

SPECIALTY CHEMICALS
Purpose: To produce esters, amides, polyesters and metal soaps.
Role of Hydroxystearic: Bifunctional building block with acid and hydroxyl groups.

WHICH PROBLEMS CAN HYDROXYSTEARIC HELP SOLVE?

LIQUID OILS THAT NEED TO STAY IN PLACE
Lubricants that run off bearings or cosmetic oils that leak from sticks can be structured with Hydroxystearic or its soaps.

GREASE SOFTENING AT HIGH TEMPERATURE
Simple stearate greases soften at relatively low temperatures. Lithium 12-hydroxystearate and complex greases based on Hydroxystearic offer higher dropping points and better heat resistance.

STICKS THAT BEND OR SWEAT IN WARM CONDITIONS
Adding Hydroxystearic can increase the firmness and heat stability of cosmetic sticks and reduce oil sweating.

POOR PIGMENT DISPERSION
Pigments that agglomerate in oils or binders can be better dispersed with the help of Hydroxystearic.

SAGGING AND SETTLING IN COATINGS
The crystal network formed by Hydroxystearic derivatives can reduce sagging on vertical surfaces and settling of pigments during storage.

These effects depend on the complete formulation and process, Hydroxystearic should be evaluated in trials for each system.

THINGS TO CONSIDER WHEN USING HYDROXYSTEARIC

The most common mistake with Hydroxystearic is to ignore the effect of processing conditions. Gel and grease structure depend strongly on heating temperature, cooling rate and shear, not only on the amount of 12-HSA used.

POINTS TO CONSIDER:

CHOOSE THE GRADE (TECHNICAL, COSMETIC, HIGH PURITY) SUITABLE FOR THE APPLICATION.
Use hydroxyl value and acid value to calculate dosing and alkali requirements.
Dissolve Hydroxystearic completely above its melting point before cooling.
Control cooling rate and shear to obtain reproducible gel or grease structure.
Avoid prolonged overheating, which can darken the product or cause side reactions.
Check compatibility with other waxes, oils and additives.
In emulsions, adjust the neutralizing agent and pH carefully.
Avoid dust formation when handling powder or fine flakes.
Ground equipment when handling large quantities of powder.

The castor-derived structurant is not classified as hazardous under GHS according to supplier safety data sheets, but fine dust may form combustible dust concentrations in air. Dust may cause mechanical irritation of the eyes and respiratory tract. Handling should be done with dust control, safety glasses and gloves, and ignition sources should be kept away from areas where dust may form.

INITIAL FORMULATION APPROACHES FOR HYDROXYSTEARIC

The examples below are laboratory starting points for evaluating Hydroxystearic. They are not validated commercial formulations. Raw material grades, equipment and process conditions can strongly affect the results, so each example must be adapted and checked for performance and safety.

The percentage compositions added below are illustrative laboratory starting mixtures (% w/w), not validated commercial recipes. Each totals 100 % on the stated basis, confirm ingredient grades and optimise processing, performance and stability.

EXAMPLE 1: LABORATORY LITHIUM 12-HYDROXYSTEARATE GREASE

Objective: To evaluate the effect of Hydroxystearic level on the consistency, dropping point and mechanical stability of a lithium grease in mineral base oil.

INITIAL COMPONENTS:

Hydroxystearic: approx. 8, 10 and 12 % of the final grease
Lithium hydroxide monohydrate: stoichiometric amount calculated from the acid value of the Hydroxystearic
Mineral base oil (e.g. ISO VG 100–220): balance
Water: small amount for saponification, removed during processing
Antioxidant: approx. 0.5 %, added during cooling

APPLICATION APPROACH:

Part of the base oil and the Hydroxystearic are charged to a heated kettle and melted at about 80–90 °C.
Lithium hydroxide is added as an aqueous solution or slurry, and saponification is carried out under stirring.
Water is removed by heating, and the soap-oil mixture is heated further to dissolve the soap completely, typically to around 200 °C, depending on the formulation.
The remaining base oil is added to cool the batch under controlled conditions.
Additives are added at a suitable lower temperature, and the grease is milled or homogenized.
Cone penetration, dropping point, mechanical stability, oil separation and water resistance are measured.
Hot oil, caustic solutions and steam must be handled with suitable protective equipment.

ILLUSTRATIVE INITIAL REACTION CHARGE FOR THE 10 % ACID EVALUATION (% W/W)
Hydroxystearic: 10.00 %
Lithium hydroxide monohydrate: 1.35 %
Mineral base oil: 86.15 %
Water for saponification: 2.00 %
Antioxidant: 0.50 %
Total: 100.00 %
This illustrates an initial charge, not a final grease with exactly 10 % acid-derived material. Calculate alkali from the actual acid value and hydroxide purity, the stated amount approximates an acid value of 180 mg KOH/g. Water removal changes the final mass fractions. Recalculate and renormalise each 8 and 12 % target trial on the intended final-grease basis.

EXAMPLE 2: OIL GEL STRUCTURED WITH HYDROXYSTEARIC

Objective: To determine the minimum Hydroxystearic level required to gel different oils and to compare gel hardness and oil separation.

INITIAL APPROACH:

Hydroxystearic (cosmetic grade): approx. 2, 4, 6 and 8 %
Oils: mineral oil, a light ester (e.g. isopropyl myristate or caprylic/capric triglyceride) and a vegetable oil, tested separately
Optional co-structurant: a small amount of wax for comparison

APPLICATION APPROACH:

Hydroxystearic is dispersed in the oil and heated to about 85–90 °C until completely dissolved.
The clear solution is poured into molds and cooled at two different rates (room temperature and fast cooling).
Gelation, appearance, hardness and oil separation after storage are evaluated.
The effect of oil polarity and cooling rate on gel strength is compared.

ILLUSTRATIVE INITIAL OIL-GEL COMPONENTS (% W/W)
Hydroxystearic (cosmetic grade): 4.00 %
Selected oil, tested separately: 96.00 %
Total: 100.00 %
For the 2, 6 and 8 % acid trials, use respectively 98, 94 and 92 % selected oil. An optional co-structurant replaces an equal mass of oil and must be included in the 100 % total.

EXAMPLE 3: HYDROXYSTEARIC AS A CO-STRUCTURANT IN A DEODORANT STICK

Objective: To evaluate how partial replacement of stearyl alcohol or wax by Hydroxystearic affects stick hardness, heat stability and skin feel.

INITIAL APPROACH:

Stearyl alcohol: approx. 15–20 %, reduced as Hydroxystearic is added
Hydroxystearic: approx. 0, 2, 4 and 6 %
Hydrogenated castor oil: approx. 2–4 %, kept constant
Emollient oil or ester: balance of the oil phase
Active ingredient and powders: according to product type, kept constant

APPLICATION APPROACH:

All structuring materials and oils are melted together at about 80–85 °C.
Powders and actives are dispersed under stirring.
The mixture is cooled slightly and poured into stick containers.
Hardness, pay-off, heat stability, whitening and skin feel are evaluated.
The formulation is tested for stability at different temperatures.

ILLUSTRATIVE INITIAL COMPONENTS FOR THE 4 % ACID STICK TRIAL (% W/W)
Stearyl alcohol: 16.00 %
Hydroxystearic: 4.00 %
Hydrogenated castor oil: 3.00 %
Emollient oil or ester: 57.00 %
Active ingredient and powder package: 20.00 %
Total: 100.00 %
This holds stearyl alcohol plus acid at 20 %. For the 0, 2 and 6 % acid trials, use respectively 20, 18 and 14 % stearyl alcohol, the final level extends the initial alcohol range to preserve the replacement comparison. The active/powder fraction is illustrative: select its identity and level for the intended product and applicable requirements, then rebalance emollient to 100 %.

HYDROXYSTEARIC SIMILAR PRODUCTS AND ALTERNATIVES

HYDROXYSTEARIC AND STEARIC ACID
Stearic acid is cheaper and widely used for simple soaps and emulsions, but lacks the hydroxyl group. Stearate greases have lower dropping points and weaker fiber networks than 12-hydroxystearate greases.

HYDROXYSTEARIC AND HYDROGENATED CASTOR OIL
Hydrogenated castor oil (castor wax) is the triglyceride of 12-HSA. It is used as a wax and rheology additive but does not form soaps directly unless it is saponified. In some grease processes, it can be used as a source of 12-HSA through in-situ saponification.

Hydroxystearic and lithium 12-hydroxystearate
Pre-formed lithium 12-hydroxystearate can be dispersed in oil to make grease without an in-house saponification step. It is more convenient but generally more expensive than making the soap from Hydroxystearic.

HYDROXYSTEARIC AND OTHER THICKENERS
In greases, polyurea, calcium sulfonate complex, aluminum complex and clay (bentonite) thickeners are alternatives for special requirements. In cosmetics and coatings, waxes, fumed silica, organoclays, polyamides and ethylcellulose are alternative structuring agents.

The choice of alternative should be confirmed through laboratory testing in the target system.

QUALITY CONTROL AND PURCHASING CRITERIA FOR HYDROXYSTEARIC

RECOMMENDED INFORMATION TO REVIEW BEFORE PURCHASING:

PRODUCT GRADE (TECHNICAL, COSMETIC, HIGH PURITY)
Physical form (flakes, powder, lumps)
Acid value
Saponification value
Hydroxyl value
Iodine value
Color (Gardner)
Melting point or titer
Moisture
Ash and metal content
Fatty acid composition (12-HSA and stearic acid content)
Origin (castor oil source) and certifications if required
Technical Data Sheet (TDS)
Safety Data Sheet (SDS)
Certificate of Analysis (COA)
Batch number and production date
Packaging type and net quantity
Storage conditions and shelf life
REACH registration information

The COA confirms the analysis of a specific batch, the TDS describes the typical properties of the grade, and the SDS covers hazards and safe handling. For grease production, batch-to-batch consistency of hydroxyl and acid values is especially important.

STORAGE AND HANDLING OF HYDROXYSTEARIC

HYDROXYSTEARIC SHOULD BE STORED IN TIGHTLY CLOSED BAGS OR CONTAINERS IN A COOL, DRY, WELL-VENTILATED PLACE, PROTECTED FROM HEAT, MOISTURE AND DIRECT SUNLIGHT.
Because the melting point is around 72–80 °C, flakes can stick together if stored at high temperatures or under heavy stacking. Pallets should not be stored near heat sources.
The product should be kept away from strong oxidizing agents and from strong bases unless used in a controlled reaction.
Dust formation should be minimized during handling. Equipment used for conveying or milling powder should be grounded to prevent static discharge.
Transport: Hydroxystearic is not regulated as dangerous goods for road, sea or air transport according to supplier safety data sheets and has no UN number.
In case of spillage, the material should be swept up or vacuumed with minimal dust generation and placed in suitable containers for reuse or disposal. Release to drains and water should be avoided.

SAFETY INFORMATION OF HYDROXYSTEARIC

Hazard classification: Hydroxystearic is not classified as hazardous under GHS according to supplier safety data sheets. Some safety data sheets note that fine dust may form combustible dust concentrations in air.
Eyes: Dust may cause mechanical irritation. Rinse with water for several minutes.
Skin: Generally low irritation potential, wash with soap and water after contact. Molten product can cause burns.
Inhalation: Avoid inhaling dust, move to fresh air if irritation occurs.
Ingestion: Rinse mouth, seek medical advice if discomfort occurs.
Fire: Hydroxystearic is a combustible solid with a flash point above 210 °C. Suitable extinguishing media are water spray, foam, dry chemical and carbon dioxide. Combustion produces carbon oxides.
Personal protection: Safety glasses, gloves and dust protection where dust is generated, heat-resistant gloves and face protection when handling molten product.
Environment: Large quantities should not be released into drains, soil or surface water.
Waste: Dispose of according to local regulations.

WHAT SHOULD BE CONSIDERED WHEN BUYING HYDROXYSTEARIC?

BEFORE PURCHASING, THE FOLLOWING INFORMATION SHOULD BE CLARIFIED:

APPLICATION (GREASE, COSMETICS, COATINGS, INKS, ADHESIVES, CHEMICAL SYNTHESIS)
Required grade and physical form
Minimum hydroxyl value and acid value range
Maximum iodine value and color
Melting point or titer requirement
Origin, sustainability or quality declarations, if required
Quantity and packaging (25 kg bags, big bags)
Documentation (TDS, SDS, COA, REACH)
Current product specification if replacing an existing supply

The price of Hydroxystearic depends mainly on castor oil prices, which are influenced by harvests in the main producing countries, as well as hydrogen and energy costs, grade, order volume, packaging and logistics.

SUPPLY OF HYDROXYSTEARIC FROM ATAMAN KIMYA

The hydroxylated fatty acid is a castor-oil-based hydroxy fatty acid used mainly in lubricating greases, cosmetics, coatings, inks and specialty chemicals. Companies planning to purchase it should define the required grade, specification and packaging in advance.
Ataman Kimya can provide information on available grades, specifications, packaging and price quotations for Hydroxystearic.
Current stock, origin and specification details should be confirmed with Ataman Kimya before ordering.

SHARING THE FOLLOWING INFORMATION HELPS PREPARE A QUOTATION FOR HYDROXYSTEARIC:

APPLICATION AND TARGET MARKET
Required grade and key specification limits
Estimated quantity
Packaging preference
Required documents

FREQUENTLY ASKED QUESTIONS ABOUT HYDROXYSTEARIC

WHAT IS HYDROXYSTEARIC?
Hydroxystearic (12-hydroxystearic acid, 12-HSA) is a saturated C18 fatty acid with a hydroxyl group on carbon 12. It is made from hydrogenated castor oil and used as a grease thickener, oil gelling agent and chemical intermediate.

WHAT IS THE CAS NUMBER OF HYDROXYSTEARIC?
The CAS number is 106-14-9.

WHAT IS THE EC NUMBER OF HYDROXYSTEARIC?
The EC number is 203-366-1.

WHAT IS THE CHEMICAL FORMULA OF HYDROXYSTEARIC?
The formula is C18H36O3 and the molecular weight is 300.48 g/mol.

WHAT IS THE INCI NAME OF HYDROXYSTEARIC?
The INCI name is Hydroxystearic Acid.

IS HYDROXYSTEARIC THE SAME AS STEARIC ACID?
No. Stearic acid has no hydroxyl group. Hydroxystearic has a hydroxyl group on carbon 12, which gives it a higher melting point and much stronger gelling and thickening properties.

HOW IS HYDROXYSTEARIC MADE?
Castor oil is hydrogenated to give hydrogenated castor oil, which is then hydrolyzed to release Hydroxystearic and glycerin.

WHAT IS HYDROXYSTEARIC USED FOR?
It is used mainly to make lithium and calcium greases, and also as a gelling and structuring agent in cosmetics, coatings, inks, adhesives and polishes, and as an intermediate for esters and other derivatives.

HOW DOES HYDROXYSTEARIC THICKEN GREASE?
It is converted into lithium or calcium soap, which crystallizes into a fiber network that holds the base oil.

HOW MUCH HYDROXYSTEARIC IS USED IN GREASE?
Lithium greases typically contain around 6–14 % soap thickener, depending on the desired consistency and base oil.

IS HYDROXYSTEARIC USED IN COSMETICS?
Yes. It is used in sticks, balms, lipsticks, pencils, hair waxes, creams, lotions and soaps as a structuring agent and co-emulsifier.

IS HYDROXYSTEARIC SOLUBLE IN WATER?
No. It is insoluble in water but dissolves in hot oils and many organic solvents.

WHAT IS THE MELTING POINT OF HYDROXYSTEARIC?
Technical grades melt at about 72–80 °C, high-purity material melts at about 80 °C.

IS HYDROXYSTEARIC HAZARDOUS?
It is not classified as hazardous under GHS according to supplier safety data sheets, but fine dust may form combustible dust concentrations in air.

WHAT IS THE UN NUMBER OF HYDROXYSTEARIC?
It is not regulated as dangerous goods for transport and has no UN number.

DOES HYDROXYSTEARIC HAVE AN E NUMBER?
No. It is not a food additive.

IS THERE AN ALTERNATIVE TO HYDROXYSTEARIC?
Stearic acid, hydrogenated castor oil, pre-formed lithium 12-hydroxystearate, polyurea, calcium sulfonate complex, organoclays, waxes and polyamides can be alternatives depending on the application.

HOW SHOULD HYDROXYSTEARIC BE STORED?
In closed packaging in a cool, dry and well-ventilated place, away from heat, moisture and strong oxidizing agents.

WHAT DOCUMENTS SHOULD BE REQUESTED WHEN BUYING HYDROXYSTEARIC?
TDS, SDS and COA, together with REACH information and any origin or quality declarations required.

WHAT TECHNICAL SPECIFICATIONS ARE IMPORTANT WHEN BUYING HYDROXYSTEARIC?
Hydroxyl value, acid value, saponification value, iodine value, color, melting point or titer and moisture.

HYDROXYSTEARIC – TECHNICAL SUMMARY

Hydroxystearic (12-hydroxystearic acid, 12-HSA, CAS 106-14-9, EC 203-366-1, C18H36O3, 300.48 g/mol) is a saturated C18 hydroxy fatty acid made from hydrogenated castor oil. It is supplied as off-white flakes or powder with a melting point of about 72–80 °C.
Its carboxylic acid and mid-chain hydroxyl groups allow it to form fibrous crystal networks, making it an efficient organogelator and the basis of lithium and calcium 12-hydroxystearate greases.
Technical grades contain some stearic acid and are specified mainly by hydroxyl value, acid value, iodine value, color and melting point.
The hydroxy fatty acid is used in lubricating greases, cosmetics, coatings, inks, hot-melt adhesives, polishes, rubber and plastics, and as an intermediate for esters, polyesters, metal soaps and PEG hydroxystearates.
It is not classified as hazardous under GHS according to supplier safety data sheets and is not regulated for transport, but dust formation should be controlled.
Companies planning to source Hydroxystearic through Ataman Kimya are advised to share their application, required grade, specifications, quantity and documentation needs to confirm current product, stock, origin, packaging and quotation details.

The castor-derived structurant can be sourced from ATAMAN KİMYA. For further information and supply inquiries about Hydroxystearic, please contact ATAMAN KİMYA.