2,2,4-Trimethylpentane

2,2,4-Trimethylpentane

Names
IUPAC name 2,2,4-Trimethylpentane
Other names 224TMP Iso-octane Isobutyltrimethylmethane
Properties
Chemical formula	C8H18
Molar mass	114.23 g/mol
Appearance	Colorless liquid
Odor	Gasoline-like
Density	0.692 g/cm3
Melting point	−107.38 °C (−161.28 °F; 165.77 K)
Boiling point	99.30 °C (210.74 °F; 372.45 K)
Solubility in water	Almost insoluble in water
Solubility	Miscible with acetone, benzene, carbon disulfide, carbon tetrachloride, chloroform, dichloromethane, diethyl ether, dimethylformamide, ethanol, heptane, toluene, xylene
Vapor pressure	5.5 kPa (at 21 °C)
Thermochemistry
Std molar entropy (So298)	328.03 J·K−1·mol−1
Std enthalpy of formation (ΔfHo298)	−260.6 to −258.0 kJ·mol−1
Hazards
Safety data sheet	Sigma-Aldrich
Flash point	−12 °C (10 °F; 261 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

2,2,4-Trimethylpentane, also known as iso-octane or simply 224TMP, is an organic compound, an isomer of octane (C₈H₁₈).

This particular isomer is an important component of gasoline and the standard 100 point on the octane rating scale (with 0 point being heptane).

Properties

Chemical

2,2,4-Trimethylpentane is exceedingly flammable in the presence of oxygen, and when ignited will burn to release carbon dioxide and water vapors.

C₈H₁₈ + 25/2 O₂ → 8 CO₂ + 9 H₂O

Physical

2,2,4-Trimethylpentane is an odorless colorless liquid, insoluble in water but miscible with many organic solvents. It lighter than water, with a density of 0.692 g/l. 224TMP has a boiling point of 99.1 °C and a melting point of −107.44 °C. It is very flammable, with a flash point of -12 °C and an autoignition temperature of 396 °C.

Availability

2,2,4-Trimethylpentane is available in high octane gasoline, and can be extracted via fractional distillation or rectification, depending on the composition of gasoline.

Preparation

Industrially it is produced by distillation of petroleum.

Another route involves the dimerization of isobutylene, using an Amberlyst catalyst, method that produces a mixture of iso-octenes. This mixture is hydrogenated to yield 2,2,4-trimethylpentane.

Projects

• Organic extractions
• Pepsin extraction

Handling

Safety

2,2,4-Trimethylpentane poses little toxicity, though its vapors are irritant to the nose, lungs and eyes.

Storage

224TMP should be stored in closed glass or PE bottles away from any heat source.

Disposal

2,2,4-Trimethylpentane can be safely burned.