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Alkanes are saturated hydrocarbons with general formula C_nH_{2n+2}.
The category "C15-19 alkanes" refers to technical mixtures made up primarily of linear (n-alkanes) and branched alkanes whose carbon counts fall between 15 and 19.
While discrete pure compounds exist (e.g., pentadecane C15H32, hexadecane C16H34, heptadecane C17H36, octadecane C18H38, nonadecane C19H40), industrially supplied C15-19 products are typically complex mixtures produced by petroleum fractionation and/or synthetic/biotechnological routes.
This review considers the chemical, physical, toxicological, environmental, regulatory, and application-relevant aspects of C15-19 alkane mixtures.
The review is intended for chemists, formulators, toxicologists, regulatory specialists, and environmental scientists needing a deep, applied understanding of this ingredient class.
CAS number(s): 64742-46-7; other vendor references include 64741-76-0 and related petroleum distillate CAS ranges.
Synonyms / INCI / alternate names: C15-19 Alkane; C15-C19 alkane; Alkanes, C15–C19 (branched and linear); hemisqualane (in trade use for certain bio-derived C15-19 fractions); isododecane (related C12 but sometimes confused); "C15-19 ALKANE" (INCI name in cosmetics); petroleum distillates (hydrotreated middle fractions) containing C15–C19.
Molecular structures
The constituents are alkanes (paraffins). Straight-chain examples and formulas:
Pentadecane (n‑C15H32)
Hexadecane (n‑C16H34)
Heptadecane (n‑C17H36)
Octadecane (n‑C18H38)
Nonadecane (n‑C19H40)
Each straight-chain alkane has many structural isomers when branched isomers are included; branched isomers commonly appear in technical mixtures (isoalkanes).
INCI and trade names
In cosmetics and personal care, the INCI name is typically listed as C15-19 ALKANE.
Trade names for specific grades exist (e.g., hemisqualane-type products, proprietary emollients) and may be derived from plant-based feedstocks or petroleum.
CAS registry and EC numbers
Technical C15-19 alkane mixtures are commonly referenced using CAS 64742-46-7 (a hydrotreating/distillate petroleum fraction) or related distillate CAS identifiers used by suppliers. Different suppliers may list additional CAS identifiers for specific grades or production routes.
Production and sourcing
Petroleum-based production
Historically, mid‑chain alkanes are obtained by fractional distillation and hydrotreatment of kerosene or middle distillate fractions of crude oil.
Hydrotreating and hydrocracking/refining steps remove aromatics, sulfur, and nitrogen impurities, giving low-aromatic, saturated hydrocarbon fractions that can be further fractionated to enrich C15‑C19 carbon numbers.
Additional processes include isomerization to increase branched isoalkane content for improved volatility and sensory properties.
Synthetic and bio-based production
Modern routes include catalytic hydrogenation of olefins or oligomerization/hydroformylation sequences to produce linear or branched alkanes.
Biotechnology routes—starting from sugars (e.g., sugarcane, beet) followed by fermentation to fatty acids or long‑chain alcohols and catalytic conversion (hydrodeoxygenation/hydrogenation)—enable renewable-sourced C15‑C19 fractions marketed as "plant-derived" hemisqualane or C15‑C19 alkanes with high renewable carbon content.
Purification and formulation grades
Commercial grades vary by purity, aromatic content (<2% aromatics is common for cosmetic grades), viscosity, and origin (petroleum vs. renewable).
Suppliers provide technical data sheets (TDS) specifying aromatic content, flash point, kinematic viscosity, and maximum impurities.
Physicochemical properties
The key properties of C15‑C19 alkanes depend on exact composition. Typical ranges and behaviour:
Physical state at 20 °C: liquid (low‑melting mid‑chain alkanes; longer linear alkanes can be waxy solids but mixtures are usually liquid at room temperature)
Density: ~0.75–0.78 g·cm⁻³ (approximate; increases slightly with chain length)
Viscosity: low viscosity; suitable as lightweight emollients and solvents
Boiling range: generally mid‑distillate range (~250–360 °C depending on composition)
Vapor pressure: very low at room temperature (practically non‑volatile compared with low‑MW hydrocarbons)
Solubility: insoluble in water; soluble in non‑polar organic solvents; miscible with many oils and silicone fluids
Reactivity: chemically inert under normal conditions; stable to oxygen except slow oxidative processes at elevated temperatures; resistant to hydrolysis; can be hydrogenated/refined further
Detailed tables with specific property values for pentadecane through nonadecane and for representative isoalkanes are included in the Appendix.
Analytical characterization
Analytical techniques commonly used to characterize C15‑19 alkane mixtures include:
Gas chromatography (GC) and GC–MS
High‑resolution GC with flame ionization detection (GC‑FID) or mass spectrometry (GC‑MS) is the standard for composition analysis, isomer profiling, and purity checks.
Capillary columns (e.g., non‑polar stationary phases) separate n‑alkanes and branched isomers; retention indices and MS fragmentation patterns support identification.
Simulated distillation (ASTM D2887 / ASTM D6352)
Used for boiling point distribution of complex hydrocarbon mixtures.
Provides distillation curve and fractionation data useful for refining and specification.
NMR spectroscopy
¹H and ¹³C NMR provide information on branching (methyl/ methylene ratios) and can be used for quality control when combined with chromatographic separation.
FT‑IR and Raman
Useful for functional group absence/presence checks (confirming saturated hydrocarbon fingerprint; absence of significant oxygenated or aromatic functionality).
Other methods
Elemental analysis (CHN), sulfur/nitrogen speciation (ASTM methods), and aromatic content by HPLC or UV methods may be required for regulatory compliance.
Behavior in formulations and mechanisms of action
In cosmetic and topical formulations, C15‑19 alkanes act primarily as light emollients and solvents. Their attributes:
High spreadability: low surface tension supports smooth application and rapid spread on skin
Non‑greasy feel: mid‑chain alkanes provide dry, powdery sensory profiles compared with heavier oils
Solubilizing capability: useful for dissolving non‑polar actives, fragrances, and UV filters
Compatibility: mix well with silicones, esters, and many vegetable oils; can replace or dilute cyclomethicone or volatile silicones in formulations
Evaporation profile: depending on branching, some grades have slight volatility (giving a dry finish) while linear fractions persist as emollients
SAFETY INFORMATION ABOUT C15-19 ALKANE
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
