Octadecane Chemical Properties

Melting point:

28 °C

Boiling point:

317 °C(lit.)

Density 

0.777 g/mL at 25 °C(lit.)

vapor density 

8.8 (vs air)

vapor pressure 

1 mm Hg ( 119 °C)

refractive index 

1.4390

Flash point:

330 °F

storage temp. 

room temp

solubility 

<0.0001g/l insoluble

form 

Crystalline Mass/Melt

Specific Gravity

0.7822

color 

White

Water Solubility 

No rapid reaction with water.

Thermal Conductivity

0.138 W/(m·K) at 25 ℃

BRN 

1740138

Henry's Law Constant

1.6×10^-6 mol/(m³Pa) at 25℃, Eastcott et al. (1988)

Stability:

Stable. Combustible. Incompatible with strong oxidizing agents.

Major Application

petroleum

Cosmetics Ingredients Functions

SOLVENT
PERFUMING
SKIN CONDITIONING
SKIN CONDITIONING - EMOLLIENT

InChI

1S/C18H38/c1-3-5-7-9-11-13-15-17-18-16-14-12-10-8-6-4-2/h3-18H2,1-2H3

InChIKey

RZJRJXONCZWCBN-UHFFFAOYSA-N

SMILES

CCCCCCCCCCCCCCCCCC

LogP

9.32 at 20℃

CAS DataBase Reference

593-45-3(CAS DataBase Reference)

NIST Chemistry Reference

Octadecane(593-45-3)

EPA Substance Registry System

Octadecane (593-45-3)

Safety Information

Hazard Codes 

Xi,Xn

Risk Statements 

36/37/38-66-65

Safety Statements 

26-36-62-24-23

WGK Germany 

3

Autoignition Temperature

455 °F

TSCA 

TSCA listed

HS Code 

29011000

Storage Class

10 - Combustible liquids

Hazard Classifications

Asp. Tox. 1

Hazardous Substances Data

593-45-3(Hazardous Substances Data)

MSDS

• Language:English Provider:ACROS
• Language:English Provider:SigmaAldrich
• Language:English Provider:ALFA

Octadecane Usage And Synthesis

Description

Octadecane is an alkane hydrocarbon that has the molecular formula CH3(CH2)16CH3. It is a straight-chain alkane that carries 18 carbon atoms. Octadecane has a role as a plant metabolite and a bacterial metabolite. It is found in alcoholic beverages, hop oil, aband other plant resources. Octadecane is a colorless liquid that has a fuel-like smell. It is soluble in water, slightly soluble in ethanol and soluble. It is also soluble in acetone, ethyl ether, chloroform, petroleum, ether, and coal tar hydrocarbons.

Chemical Properties

white crystals or powder

Uses

n-octadecane is used as a solvent, a lubricant, transformer oil and an anti-corrosion agent. It is also used in paraffin and as a chemical intermediate in organic synthesis. It plays an important role in pheromones as a chemical messenger. N-Octadecane/ molecular sieve 5A composites find application as thermal storage material.

Definition

ChEBI: A straight-chain alkane carrying 18 carbon atoms.

Synthesis Reference(s)

The Journal of Organic Chemistry, 52, p. 472, 1987 DOI: 10.1021/jo00379a037
Tetrahedron Letters, 31, p. 5093, 1990 DOI: 10.1016/S0040-4039(00)97814-6

General Description

Colorless liquid.

Reactivity Profile

Saturated aliphatic hydrocarbons, such as Octadecane, may be incompatible with strong oxidizing agents like nitric acid. Charring of the hydrocarbon may occur followed by ignition of unreacted hydrocarbon and other nearby combustibles. In other settings, aliphatic saturated hydrocarbons are mostly unreactive. They are not affected by aqueous solutions of acids, alkalis, most oxidizing agents, and most reducing agents. When heated sufficiently or when ignited in the presence of air, oxygen or strong oxidizing agents, they burn exothermically to produce carbon dioxide and water.

Fire Hazard

Combustible.

Purification Methods

Crystallise it from acetone and distil it from sodium in a vacuum. [Beilstein 1 IV 553.]

Properties and Applications

Octadecane (n-Octadecane) is part of the paraffin family; its chemical formula is C₁₈H₃₈, and it is a solid at room temperature. Its melting point lies between 28 and 30 °C, its heat capacity is 2.22 J/K·g, and its viscosity is 4.21 mPa·s (20 °C). During the phase transition, the thermal conductivity changes from 0.198 W/m·K (solid) to 0.222 W/m·K (liquid). Octadecane can be used as a phase-change material (PCM) to prepare novel phase-change composites suitable for building cooling applications. Recycled aluminium was added to these composites at concentrations of 7% and 7.5% (by volume) as a thermal conductivity enhancer to prevent sinking during the molten phase and to improve thermal conductivity. Furthermore, research has shown that, compared to octadecane, the addition of aluminium shavings can increase the thermal conductivity of the composite by 100% (octadecane-short aluminium) and 600% (octadecane-long aluminium), whereas the mass increase remains relatively low^[1].

References

[1] Nicoleta Cobîrzan. (2025). Properties of n-Octadecane PCM Composite with Recycled Aluminum as a Thermal Enhancer. Materials, 18 24. https://doi.org/10.3390/ma18245638

Octadecane(593-45-3)Related Product Information

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