What chem. is used to increase octane in gas?

Question

I have heard that rubbing alcohol or moth balls would do it does anyone know about these things?

Answer 1

benzene

Answer 2

The octane number of a fuel was originally increased by the addition of metal compounds such as tetraethyl lead(TEL). This increased the octane number of the fuel, but the effect was to increase the rate at which the fuel burnt in the engine. Due to the toxicity of the metals and in particular lead this has now been discontinued. The phenomenon caused by the slow combustion of the fuel in the engine is called "knocking" due to the noise it makes in the engine. These additives are generically called anti knocking agents

Antiknock agents are grouped into "high percentage" additives, such as alcohol, and "low percentage" additives based on heavy elements. Since the main problem with TEL is its lead content, many alternative additives that contain less poisonous metals have been examined. A manganese-carrying additive, methylcyclopentadienyl manganese tricarbonyl (MMT or methylcymantrene), is used as an antiknock agent in Canada, but its use as a fuel additive had been banned in the US until 1995. Ferrocene, an organometallic compound of iron, has also been reported as an effective antiknock agent.

High-percentage additives are organic compounds that do not contain metals, but they require much higher blending ratios, such as 20-30% for benzene and ethanol. Oxygenates, mainly methanol-derived MTBE and ethanol-derived ETBE have largely substituted the need for TEL. MTBE has environmental risks of its own and there are also bans on its use. ETBE, on the other hand, requires more expensive ethanol as a starting material.

Improvements of the gasoline itself decrease the need for separate antiknock agents. Synthetic iso-octane and alkylate are examples of such blending stocks. Benzene and other high-octane aromatics can be also blended to raise the octane number, but they are disfavored today because of toxicity and carcinogenity.

If you are looking for some do-it -yourself additive for home use, there are many such products available from any auto hardware shop. You must decide for yourself whether the claims made by the manufacturers are justified.