POLYGLYCERYL-2 TRIISOSTEARATE

Polyglyceryl‑2 Triisostearate is a nonionic, lipophilic polyglycerol ester widely used in cosmetic and personal care formulations as an emollient, dispersing agent (notably for pigments), and a mild emulsifier for W/O and O/W systems depending on the system design. 
Polyglycerol esters have gained traction as ‘‘mild’’ and often plant‑derived alternatives to PEG‑based esters, dovetailing with increasing consumer and regulatory interest in low‑PEG, non‑ethoxylated surfactants and emulsifiers. 
The polyglyceryl‑2 family represents low polymerization degree polyglycerols (degree of polymerization ≈2), which provide an optimal balance between hydrophilicity and lipophilicity for numerous personal care uses.

Historically, the development of polyglycerol esters built on glycerides chemistry combining polycondensed glycerol oligomers (diglycerol, polyglycerol) with fatty acids (including branched isostearic acid). 
Manufacturers formulated variants (mono‑, di‑ and tri‑esters; isostearate vs stearate) to tune HLB, melting point, and compatibility with pigments and silicones.

Synonyms: Polyglycerol‑2 Tristearate; Polyglyceryl‑2 Tristearate; Polyglycerol-2 Triisostearate; Polyglyceryl-2 Isostearate (commercial variant naming); Isooctadecanoic acid, triester with oxybispropanediol
CAS number: 120486‑24‑0

The following properties are typical or reported by suppliers; exact values should be confirmed from the specific Technical Data Sheet (TDS) for each commercial grade.
Appearance: pale yellow to amber viscous liquid or low-melting waxy material depending on grade and iodine value of the fatty acids.
Odour: faint fatty odour.
pH: not applicable (nonionic); stable across a wide pH range but ester hydrolysis can occur at extreme pH and high temperatures.
Density: ≈0.90–0.95 g·cm⁻³ (typical for C18 ester oils); consult TDS for specific gravity at 20 °C.
Viscosity: grade dependent; low to moderate viscosity fluids at 25 °C; some grades are tacky/higher viscosity — suppliers publish kinematic viscosity ranges.
HLB (Hydrophilic‑Lipophilic Balance): very low HLB (highly lipophilic) — useful as an oil‑soluble emulsifier/dispersant and emollient. 
Exact HLB is not straightforward due to polydisperse structure, but functionally PG‑2 triisostearate behaves as a lipophilic co‑emulsifier or W/O emulsifier building block.

Solubility: miscible/soluble in oils, esters, and many nonpolar solvents. 
Dispersible in water to an extent when combined with co‑emulsifiers or under high shear; suppliers often describe it as ‘dispersible in water’ depending on system and co‑surfactants.
Melting point / softening point: low melting point due to branched isostearic chains; often liquid or semi‑solid at ambient.
Cloud point / Pour point: grade dependent.
Refractive index: supplier specific; useful for QC.
Acid value, saponification value, peroxide value: reported on certificates of analysis and used to evaluate raw material quality.
Interpretation: the branched chains of isostearic acid lower crystallinity and permit transparent/non‑crystalline oily phases — a valuable property for modern lightweight emulsions and pigment dispersions.

Production and synthetic routes
Raw materials
Polyglycerol‑2 (diglycerol): prepared by controlled condensation of glycerol under catalytic conditions (acidic catalysts or enzymatic routes), then fractionated to yield low‑DP oligomers.
Isostearic acid: produced by isomerization of natural stearic/oleic feedstocks or via synthetic routes that produce methyl‑branched C18 acids; commercial isostearic acid is typically a mixture of positional isomers.
Catalysts: acid catalysts (sulfonic acids, zeolites, or solid acid catalysts) are commonly used for esterification; industrial producers may use esterification under dehydration and reduced pressure to shift equilibrium.
Reactors: batch esterification with vacuum, thin‑film evaporators for water removal or continuous esterification depending on scale.

Typical esterification process
Charge polyglycerol‑2 and isostearic acid in stoichiometric ratios (slight excess of fatty acid or polyglycerol depending on desired distribution of tri/di/mono‑esters).
Heat under inert atmosphere while removing water formed during esterification (vacuum or azeotropic distillation).
Use acidic catalyst (homogeneous or heterogeneous) to accelerate conversion; monitor acid value to endpoint.
Neutralize catalyst (if homogeneous) and deodorize/lightly strip volatiles if necessary.
Filter and polish the product; adjust specifications (e.g., acid value) and package under dry conditions.
Variants and process controls
Controlling reaction stoichiometry, temperature and vacuum determines the degree of esterification (mono/di/tri‑ester distribution).
Use of branched isostearic acid requires managing its lower melting point and viscosity for process handling.
Quality control: acid value, hydroxyl value, HPLC (or GC after derivatization) for residual polyglycerol/glycerol, and GPC for molecular weight distribution are commonly used.

Typical commercial specifications and quality attributes
Typical specification items found on a TDS/C.O.A. include:
INCI name and CAS
Appearance (colour, appearance)
Viscosity at 25 °C (or Brookfield viscosity at specified rpm and spindle)
Acid value (mg KOH/g)
Saponification value
Hydroxyl value
Water content (Karl Fischer)
Peroxide value (if applicable for oxidative stability monitoring)
Refractive index
Heavy metals (ppm) and residual catalysts
Microbial limits (especially for water‑containing products or where microbial growth is possible)
Quality can vary by supplier; for high‑performance pigment dispersions, lower water and peroxide values are desirable.

Analytical and characterization methods
Key methods used to characterize polyglyceryl esters:
FTIR (ATR): confirm ester carbonyl stretch (~1735 cm⁻¹) and C–O stretches.
NMR (¹H, ¹³C): verify ester formation, fatty acid chain composition, and glycerol backbone signals; branching patterns from isostearic acid are evident in methyl and methylene resonances.
GC‑MS (after hydrolysis/derivatization): fatty acid profile (to confirm isostearic acid signature vs linear stearate); often methylation (FAME) used.
GPC / SEC: molecular weight distribution (detect polyglycerol oligomer distribution and degree of polymerization).
HPLC (evaporative light scattering or MS detection): to separate mono/di/triester distribution.
Karl Fischer titration: water content.
Acid value titration (ASTM / ISO methods): residual free fatty acid.
Hydroxyl value: residual hydroxyl groups from under‑esterified polyglycerol.
Differential Scanning Calorimetry (DSC): thermal transitions and crystallinity information.
Rheology: viscosity profiling across temperatures and shear rates.

SAFETY INFORMATION ABOUT POLYGLYCERYL-2 TRIISOSTEARATE

First aid measures:
Description of first aid measures:
General advice:
Consult a physician. 
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
 
If inhaled:
If breathed in, move person into fresh air. 
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately. 
Wash off with soap and plenty of water.
Consult a physician.
 
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
 
If swallowed:
Do NOT induce vomiting. 
Never give anything by mouth to an unconscious person. 
Rinse mouth with water. 
Consult a physician.
 
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
 
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment. 
 
Avoid breathing vapours, mist or gas. 
Evacuate personnel to safe areas.
 
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste. 
Keep in suitable, closed containers for disposal.
 
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
 
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place. 
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
 
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
 
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles. 
Faceshield (8-inch minimum). 
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
 
Skin protection:
Handle with gloves. 
Gloves must be inspected prior to use. 
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product. 
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. 
Wash and dry hands.
 
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
 
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. 
 
If the respirator is the sole means of protection, use a full-face supplied air respirator. 
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so. 
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions. 
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
 
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company. 
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product