Methanol is insoluble in hydrocarbaons such as hexane. Moreover, methanol has lower energy density than ethanol and is more toxic.

Thank you Mario, but do you know why is it use in the range of 3-5 % in some countries.

The use of methanol for octane in gasoline has been shown to have environmental benefits, as methanol blends reduce HC, CO, PM and other exhaust emissions from most vehicles .

Methanol's high octane and oxygen content produce a cleaner burning gasoline which significantly lowers vehicle exhaust emissions. When produced from natural gas or biomass, methanol fuel has a lower carbon intensity (or carbon footprint) than gasoline produced from petroleum.

One of the most important disadvantages of using methanol in gasoline:

A bigger concern is the corrosive effects of methanol. It is safe to use in small amounts, but uncontrolled and unregulated mixing can result in concentrations high enough to cause additional wear and damage over time to sensitive gaskets and hoses in the fuel system.

the most important is preferential dissolution. It is completely and mutually soluble in water that results in case separation. the lower water phase will initiate corrosion and release and some carry over of some deposits. Problems are complex, if the methanol is admixed into the carburettor or fuel line this is beneficial to the environment in terms of emissions features. Historically methanol has been present in gasoline blends in form of MTBE, that has been banned and was substituted by ETBE.

Thanks Andras and Bahram,

Methanol is used in some country, such as China, and also, uses as an azeotrope mixture with other oxygenated compounds to overcome the solubility in water.

Do you think this mixture can overcome the corrosion problem?

Thanks,

Gobara.

as long as water is present just a proper mix of additives can do

corrosivity is a problem. Besides, some non-metallic parts (e.g. some rubbers) tend to swell when in contact with methanol. Also, methanol needs quite a lot of heat for evaporation.

In concentrations higher than 17% the mixture will separate.

Thanks Jerry and Robert,

So, do you think cars need a modification(s) in carburetor or engen to use methanol or other oxygenated compounds?

Gobara