How do you convert methane to gasoline at home?

Answer 1

It is possible to convert methane to gasoline at home, but it would be extremely expensive and to do it legally, your house would have to be in a properly zoned area and you would need a lot of different permits.

But theoretically speaking, it is possible to convert methane into C4 to C12 alkanes, with practically no alkenes. You would have to form a lot of carbon-carbon bonds, meaning that somehow you would have to get one methane molecule to react with another one, then continue adding carbons until there is a blend of alkanes containing from four to 12 carbon atoms. If the blend has a volatility within a certain range, then it would probably qualify as gasoline by someone's standards, although it would have a very poor octane rating.

Methane is nearly chemically inert under normal conditions except that of course it will react with oxygen very quickly if a source of high heat such a spark or an open flame is brought near a methane-oxygen mixture that is within the upper and lower flammability limits. I'm not a petroleum expert, but I can foresee two ways to get methane molecules to bond together, and both of them are radical processes.

This could be extremely dangerous unless the reaction is carried out at a low pressure AND the reaction is attempted first with a relatively very small number of UV photons. The number of UV photons is s-l-o-w-l-y increased until a slow reaction takes place. Then, it's not extremely dangerous because bromine reacts with alkanes much more slowly than chlorine, and especially fluorine.

If methane were blended with bromine gas in an approximately 1:0.25-0.50 molar ratio, the mixture would react if the right number of ultraviolet light photons were shone through the mixture. This would have to be done at a pressure far below atmospheric, the number of photons of UV light would need to be correctly calculated, and it should only be done in some kind of cask capable of handling a very high pressure in case of an accident that could otherwise result in an explosion. A chain reaction would take place, and a controlled chain reaction is what you need as methane is continuously bled into the reaction vessel. Once the methane addition is stopped, the chain reaction would die out in a short amount of time. This procedure would need to be carried out numerous times because a carbon-carbon bond is only formed during one of the chain-termination steps. Eventually, you will have liquids (alkanes) in the container. If they do not contain enough carbon atoms, the chain reaction can be performed in the liquid phase by adding [liquid] bromine and initiating a chain reaction with an organic peroxide. In the end, the products of the reaction would be quite a mess, but there should be a significant amount of brominated alkanes, mostly branched ones, which is what is desired, and some unbrominated alkanes.

Next, the liquid alkane bromides are drained off and diluted in diethyl ether so that a Grignard reaction can be performed in a hood by adding small pieces of magnesium metal to the mixture. Keep adding Mg until no more reaction (bubbles coming off the Mg pieces) takes place. At this point, you will have converted the alkane bromides into the alkane magnesium bromides. When water or ethanol (which reacts more slowly) is very slowly added to the mixture, the alkane magnesium bromides are converted into the respective alkanes. The ether can be evaporated off in a Roto-Vap™ leaving a mixture of mostly branched alkanes. If you are lucky, the bromination steps went far enough to form butanes through dodecanes, and you will have a crude form of gasoline. Just add about 10% diisopropyl ether to boost the octane, and it should run fine in about any car.