2,2,4-Trimethylpentane
IUPAC name	2,2,4-Trimethylpentane
Other names	Isooctane
Identifiers
CAS number	540-84-1 Y
RTECS number	SA3320000
SMILES	CC(C)(C)CC(C)C
Properties
Molecular formula	C8H18
Molar mass	114.23 g mol−1
Appearance	colorless liquid
Density	688 kg/m3, liquid
Melting point	-107.38 °C, 166 K, -161 °F
Boiling point	99.3 °C, 372 K, 211 °F
Solubility in water	Immiscible
Thermochemistry
Std enthalpy of formation ΔfHo298	−259 kJ/mol
Std enthalpy of combustion ΔcHo298	−5461 kJ/mol
Standard molar entropy So298	328 J·K−1·mol−1
Hazards
MSDS	MSDS
EU classification	Flammable (F) Harmful (Xn) Dangerous for the environment (N)
R-phrases	R11 R38 R50/53 R65 R67
S-phrases	(S2) S9 S16 S29 S33 S60 S61 S62
Flash point	4.5 °C
Autoignition temperature	417 °C
Explosive limits	1.1–6.0%
Related compounds
Related alkanes	Heptane Octane
Related compounds	Hexadecane
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

2,2,4-Trimethylpentane, also known as isooctane or iso-octane, is an octane isomer which defines the 100 point on the octane rating scale (the zero point is n-heptane). It is an important component of gasoline.

Isooctane is produced on a massive scale in the petroleum industry, usually as a mixture with related hydrocarbons. The alkylation process alkylates isobutane with isobutylene using a strong acid catalyst. In the NExOCTANE process, isobutylene is dimerized into isooctene and then hydrogenated to isooctane.^[1]

Dimerisation of isobutylene to create isooctane or 2,2,4-trimethylpentane

[edit] Hazards

This compound is very hazardous to the human body. When 2,2,4-trimethylpentane is inhaled it can cause confusion, dizziness, headaches, nausea, and severe vomiting. If the substance comes into contact with human skin it can cause the area to become dry, turn red, and become extremely painful. A study was done on the long term exposure to isooctane in male rats. The study showed that it caused kidney damage, altered renal functions and a higher production of alphZuglobulin protein. ^[2]

When 2,2,4-trimethylpentane is exposed to air moisture it can explode. It must be kept in a well ventilated room or container so moisture does not build up and cause the compound to explode. It is also very flammable and needs to be kept at a stable room temperature around 20C. ^[3]

Isooctane is a hydrocarbon molecule which means it has Carbon-Hydrogen bonds as a base. This compound is classified an organic compound because of its Carbon-Hydrogen bonds.

[edit] Discovering the Uses

Knocking occurred in many automobiles of the 1920’s. This caused many problems not only to the engine but it also caused them to be less fuel efficient. Knocking was considered to be several chemical reactions taking place in the fuel-air mixture. The first chemical reaction that toke place happened in the fuel-air mixture as soon as it is drawn into the cylinder during the intake stroke. As this mixture is heated rapidly by the cylinder walls, by compression prior to the power stroke and by the burning gases after the spark plug fires, some of the hydrocarbons undergo a series of creaking and oxidation reactions which produce unstable compounds. The spreading flame front sweeps across the combustion chamber heating and compressing the unburned portion of the fuel so that these unstable compounds auto ignite and detonate throughout the cylinder instantaneously. The piston is then given a sharp, hard rap to which it cannot respond because it is physically connected to the crankshaft.

In 1919 Charles Kettering and Thomas Midgley Jr, began experimenting with different compounds to identify the source of the knocking, and how to stop it. After several tests they discovered a very important compound called TEL or tetraehyllead. This helped Graham Edgar in 1926 discover 2,2,4-trimethylpentane in gasoline. Graham added different kinds and amounts of n-heptane and figured out that the knocking stopped when 2,2,4-trimethylpentane was added. This was how the octane rating scale was started.^[4]

[edit] Extras

- The best anti-knock agent is Lead, but because lead is very harmful to the environment the gasoline manufacturers, went back to using 2,2,4-trimethylpentane.

- Many anti-knock agents have been manufactured but 2,2,4-trimethylpentane is still the most widely used.^[5]

- Experiments have been done to see the effect of pressure on 2,2,4-trimethylpentane mobility of electrons. The mobility increased at room temperature with high pressures and decreased with the same pressure but high temperatures.^[6]

[edit] See also

• Oil refinery
• Antiknock agents

[edit] References

1. ^ NExOCTANE - Neste Jacobs
2. ^ http://www.epa.gov/iris/subst/0614.htm
3. ^ http://webbook.nist.gov/cgi/cbook.cgi?ID=540-84-1
4. ^ http://books.google.ca/books?id=J_AkNu-Y1wQC&pg=PA62&lpg=PA62&dq=Graham+Edgar+2,2,4-trimethylpentane&source=bl&ots=j-EpdKDSiw&sig=Wcig6ufy1YJ3cyI-G41AyInkWwU&hl=en&ei=66YmS_nFLcGwlAfTurGMCg&sa=X&oi=book_result&ct=result&resnum=5&ved=0CBgQ6AEwBA#v=onepage&q=Graham%20Edgar%202%2C2%2C4-trimethylpentane&f=false
5. ^ http://www.scientificamerican.com/article.cfm?id=carbon-hooch
6. ^ http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVT-459GYX7-5&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1135605829&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=485e953eb85c8df4e7789c0e19a3feb1

[edit] External links

• International Chemical Safety Card 0496